JP6681641B1 - Ultrasonic detecting device and method, ultrasonic detecting program - Google Patents

Abstract

An object of the present invention is to provide an ultrasonic detection device capable of preventing interference with ultrasonic waves generated by other devices. The ultrasonic detection device 11 of the present invention is a device that detects the object A1 based on the ultrasonic waves W generated by the own device. The ultrasonic detection device 11 includes ultrasonic sensors 21 and 22, a parameter changing unit and a signal determining unit. The ultrasonic sensors 21 and 22 transmit a burst wave of the ultrasonic waves W defined by a plurality of types of parameters as a transmission signal W1 and receive a reflected wave thereof as a reception signal W2. The parameter changing means changes the parameter of the transmission signal W1 a plurality of times. The signal determining means determines whether or not the parameters of the reception signal W2 change in the same tendency in association with the change of the parameter, and reflects the transmission signal W1 generated by the own device when the reception signal W2 is not interlocked. Discard it as not a wave and eliminate it. Selection diagram: Figure 2

Description

  The present invention eliminates the influence of ultrasonic waves emitted by other devices by repeatedly applying ultrasonic waves, and an ultrasonic detection device that detects an object based on the ultrasonic waves emitted by the own device, an ultrasonic detection method, and The present invention relates to an ultrasonic wave detection program therefor.

  2. Description of the Related Art Conventionally, as an ultrasonic wave detecting device for irradiating ultrasonic waves to detect an object, for example, a fish finder for detecting a fish school has been known. The fish finder has an ultrasonic sensor that transmits ultrasonic waves as a transmission signal and receives reflected waves of ultrasonic waves as a reception signal, and detects underwater by repeatedly emitting ultrasonic waves from the ultrasonic sensor. It is like this. The ultrasonic sensor generally includes a disk-shaped piezoelectric element and an acoustic matching layer bonded to the piezoelectric element.

  However, in recent years, the number of ships equipped with the same fish finder is increasing, and thus interference with other ships tends to occur. Therefore, change the values of parameters (frequency, transmission interval, etc.) in the transmission signal, and determine whether the reception signal is the reflected wave of the transmission signal generated by the own device or the transmission signal generated by another device. Various techniques have been proposed for preventing interference by performing the above (see, for example, Patent Documents 1 to 6).

Japanese Patent Laid-Open No. 2019-32207 (paragraphs [0002], [0007], etc.) JP, 2018-179676, A (claim 1, paragraph [0003], [0010], etc.) JP, 2016-85036, A (paragraph [0007] etc.) JP-A-54-103700 (claim 1 etc.) JP-A-9-21869 (claim 13, paragraph [0006], etc.) JP, 2010-185706, A (paragraph [0006] etc.)

  By the way, the process of changing the parameter value of the transmission signal is usually performed based on a predetermined program. However, if the ultrasonic sensor installed in another device changes the transmission signal based on a program similar to its own program, the parameter of the transmission signal of the other device is the parameter of the transmission signal of its own device. It may be changed in the same manner as described above. In this case, the parameter value of the transmission signal of the other device may be the same as the parameter value of the transmission signal of the own device. It is not possible to determine whether it is a wave or a transmission signal generated by another device, which may cause interference.

  The present invention has been made in view of the above problems, and an object thereof is to provide an ultrasonic detection device, an ultrasonic detection method, and an ultrasonic detection program capable of preventing interference with ultrasonic waves emitted from other devices. To provide.

  In order to solve the above-mentioned problems, the invention according to claim 1 eliminates the influence of ultrasonic waves emitted from other machines by repeatedly irradiating ultrasonic waves, and the object based on the ultrasonic waves emitted from the own machine. Is a device for detecting an ultrasonic wave, which transmits an ultrasonic burst wave defined by a plurality of types of parameters including frequency, transmission interval, amplitude, and burst length as a transmission signal, and receives the reflected wave as a reception signal. The ultrasonic sensor, a parameter changing unit that changes the type and value of the parameter in the transmission signal a plurality of times, and the value of the parameter in the reception signal changes in the same tendency in association with the change in the value of the parameter. And a signal discriminating means for discriminating the received signal when it is not interlocked and discriminating that the received signal is not a reflected wave of the transmitted signal generated by the own device. An ultrasonic detection device according to the gist thereof.

  Therefore, according to the invention of claim 1, the parameter changing means changes at least one of the type and value of the parameter in the transmission signal so that there is no regularity (claim 2). The parameters of the transmission signal of the machine can be different from the parameters of the transmission signal of the other machine. In this case, if the signal determining means determines whether or not the parameter values in the received signal change in the same tendency in association with the change in the parameter value in the transmitted signal, the received signal is transmitted by the own device. It is possible to reliably determine whether the signal is a reflected wave. As a result, it is possible to prevent interference with a transmission signal generated by another device.

  According to a third aspect of the present invention, in the learning according to the first or second aspect, a method for learning a method for shortening a time required to determine the received signal based on a change mode of the type and value of the parameter of the transmitted signal is learned. Section, a storage section for storing the learning result by the learning section, and a change mode of the parameter type and value based on the learning result stored in the storage section, and according to the determined content. The gist of the present invention is to include a change operation execution unit that causes the parameter change means to perform the change operation.

  Therefore, according to the third aspect of the present invention, the mode of changing the type and value of the parameter of the transmission signal is optimized based on the learning result by the learning unit, so that the parameter of the transmission signal is optimized according to the optimized content. By changing, it is possible to surely shorten the time required to determine the received signal.

  A fourth aspect of the present invention is a learning method according to the first or second aspect, which learns a method for shortening a time required to determine the reception signal based on a change mode of the type and value of the parameter of the transmission signal. Based on the storage unit that stores the result in advance and the learning result stored in the storage unit, a change mode of the type and value of the parameter is determined, and the change is performed by the parameter changing unit according to the determined content. The gist of the present invention is to include a change operation execution unit that causes an operation.

  Therefore, according to the invention as set forth in claim 4, the mode of changing the type and value of the parameter of the transmission signal is optimized based on the learning result stored in the storage unit. By changing the parameter of the transmission signal, it is possible to surely shorten the time required to determine the reception signal.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the parameter changing unit is configured to detect the object based on a time period from the transmission of the transmission signal to the reception of the reception signal. It is a gist to calculate the distance up to and shorten the transmission interval of the transmission signal as the distance is shorter, and lengthen the transmission interval of the transmission signal as the distance is longer.

  Therefore, according to the invention described in claim 5, since the transmission interval of the transmission signal is shortened as the distance to the target object is shorter, the transmission signal is transmitted even when the own device is closer to the target object. The object can be reliably reflected by the object, and the reception signal, which is the reflected wave of the transmission signal, can be reliably received by the ultrasonic sensor. Therefore, the received signal can be surely discriminated by the signal discriminating means.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the parameter changing unit reduces the amplitude of the transmission signal when the amplitude of the reception signal is large, and the amplitude of the reception signal. It is a gist to increase the amplitude of the transmission signal when is small.

  Therefore, according to the sixth aspect of the invention, the amplitude of the transmission signal is controlled so that the amplitude of the reception signal, which is the reflected wave of the transmission signal of interest, has a magnitude suitable for signal processing. In this case, in the receiving circuit which is a processing circuit of the received signal, the variable range of the amplification factor of the received signal can be made relatively small, or the dynamic range of AD conversion can be made relatively narrow, so that low-cost reception is possible. Circuitry can be employed. Further, when the amplitude of the received signal is large, the amplitude of the transmitted signal is made small, so that unnecessary noise can be suppressed from being dissipated and use of energy more than necessary can be suppressed. On the contrary, when the amplitude of the received signal is small, the amplitude of the transmitted signal is increased in order to avoid the calculation process with the weak received signal, so that the received signal can be reliably discriminated by the signal discriminating means.

  According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the parameter changing unit compares the frequency of the transmission signal with the frequency of the reception signal, and the frequency of the reception signal is When the frequency of the transmission signal is higher than the frequency of the transmission signal, while the frequency of the transmission signal is lowered, when the frequency of the reception signal is lower than the frequency of the transmission signal, the frequency of the transmission signal is increased. To do.

  Therefore, according to the invention described in claim 7, by lowering the frequency of the transmission signal when the frequency of the reception signal is high, the frequency of the reception signal is lowered, while the frequency of the transmission signal is reduced when the frequency of the reception signal is low. By increasing the frequency, the frequency of the received signal is increased. As a result, the frequency of the changed transmission signal can be kept within the frequency band of the ultrasonic sensor. Therefore, the reception signal, which is the reflected wave of the transmission signal, can be reliably received by the ultrasonic sensor.

  According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the ultrasonic sensor includes a first ultrasonic sensor that transmits the transmission signal and a first ultrasonic sensor. The gist of the present invention is that the second ultrasonic sensor is provided separately and receives the reception signal.

  For example, when the ultrasonic sensor is one sensor having a function of transmitting a transmission signal and a function of receiving a reception signal, the reception signal cannot be received while the transmission signal is being transmitted. For example, when the distance to the object is short, the reflected wave (reception signal) of the transmission signal returns during the transmission of the transmission signal, so that the signal discrimination means cannot discriminate the reception signal. There's a problem. Therefore, in the invention described in claim 8, the ultrasonic sensor is divided into a first ultrasonic sensor that transmits a transmission signal and a second ultrasonic sensor that receives a reception signal. The reception signal can be received by the second ultrasonic sensor even during transmission of the transmission signal from the ultrasonic sensor. Therefore, the received signal can be surely discriminated by the signal discriminating means.

  According to a ninth aspect of the present invention, in the eighth aspect, the frequency band of the first ultrasonic sensor is wider than the frequency band of the second ultrasonic sensor, and the parameter changing unit includes the The gist of the invention is to determine the amount of change in the frequency of the transmission signal so that the second ultrasonic sensor can receive the reception signal near the center frequency.

  Therefore, according to the invention of claim 9, since the frequency band of the first ultrasonic sensor is wider than the frequency band of the second ultrasonic sensor, the frequency of the transmission signal transmitted from the first ultrasonic sensor. Can be varied over a wide range. In addition, since the amount of change in the frequency of the transmission signal is determined so that the second ultrasonic sensor can receive near the center frequency, the reception signal can be reliably received by the second ultrasonic sensor. . Moreover, since it is sufficient to prepare a second ultrasonic sensor having a relatively narrow frequency band, the manufacturing cost of the second ultrasonic sensor can be suppressed.

  The invention according to claim 10 is a method for eliminating the influence of ultrasonic waves emitted by other devices by repeatedly applying ultrasonic waves, and detecting an object based on the ultrasonic waves emitted by the device itself. A parameter changing step of changing the type and value of the parameter of the ultrasonic burst wave defined by a plurality of types of parameters including frequency, transmission interval, amplitude and burst length, and the burst wave having the parameter changed. A transmission step of transmitting as a transmission signal, a reception step of receiving a reflected wave of the transmission signal as a reception signal, and the value of the parameter in the reception signal changes in the same tendency in association with the change in the value of the parameter. Signal judgment step of judging whether or not the received signal in the case of non-interlocking is not a reflected wave of the transmitted signal generated by the own device and eliminating the signal. The ultrasound detecting method for performing a plurality of times as its gist.

  Therefore, according to the invention of claim 10, in the parameter changing step, if at least one of the kind and the value of the parameter in the transmission signal is changed so as to have no regularity, the parameter of the transmission signal of the own device is changed. Can be different from the parameter of the transmission signal of the other device. In this case, in the signal determination step, if it is determined whether or not the parameter values in the received signal change in the same tendency in association with the change in the parameter value in the transmitted signal, the received signal is transmitted by the own device. It is possible to reliably determine whether the signal is a reflected wave. As a result, it is possible to prevent interference with a transmission signal generated by another device.

  The invention according to claim 11 eliminates the influence of ultrasonic waves emitted from other devices by repeatedly applying ultrasonic waves, and controls a device for detecting an object based on the ultrasonic waves emitted from the computer itself. , A parameter changing step of changing the type and value of the parameter of the ultrasonic burst wave defined by a plurality of parameters including frequency, transmission interval, amplitude and burst length, and the burst in which the parameter is changed. A transmission step of transmitting a wave to the ultrasonic sensor as a transmission signal, a reception step of receiving a reflected wave of the transmission signal as a reception signal to the ultrasonic sensor, and in the reception signal in association with a change in the value of the parameter. It is determined whether or not the values of the parameters change in the same tendency, and the received signal in the case of non-interlocking is the opposite of the transmitted signal generated by the own device. The ultrasound detecting program for executing the signal determination step and a plurality of times in sequence to eliminate to determine that it is not the wave as its gist.

  Therefore, according to the invention described in claim 11, the parameter changing step is executed based on the ultrasonic detection program, and at least one of the type and the value of the parameter in the transmission signal is changed so as not to have regularity. For example, the parameter of the transmission signal of the own device can be different from the parameter of the transmission signal of the other device. In this case, if the signal determination step is executed based on the ultrasonic detection program and it is determined whether or not the parameter values in the received signal change in the same tendency in conjunction with the change in the parameter value in the transmitted signal, It is possible to reliably determine whether or not the received signal is a reflected wave of the transmitted signal generated by the own device. As a result, it is possible to prevent interference with a transmission signal generated by another device.

  As described above in detail, according to the invention described in claims 1 to 9, it is possible to provide an ultrasonic wave detection device capable of preventing interference with an ultrasonic wave generated by another machine. Further, according to the invention described in claim 10, it is possible to provide an ultrasonic wave detection method capable of preventing interference with an ultrasonic wave generated by another machine. Further, according to the invention described in claim 11, it is possible to provide an ultrasonic wave detection program capable of preventing interference with an ultrasonic wave generated by another device.

Explanatory drawing which shows the fishing boat carrying the fish finder of 1st Embodiment. The schematic block diagram which shows a fish finder. Sectional drawing which shows an ultrasonic sensor. The block diagram which shows the electric constitution of a fish finder. The time chart which shows a transmission signal. Transmission interval change amount pattern distribution table. The flowchart which shows the arithmetic processing performed by CPU of a control apparatus. The flowchart which shows the arithmetic processing performed by CPU of a control apparatus. Frequency variation pattern distribution table. The block diagram which shows the electric constitution of the fish finder in 3rd Embodiment. The block diagram which shows the electric constitution of the fish finder in 4th Embodiment.

[First Embodiment]
Hereinafter, a first exemplary embodiment of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the fish finder 11 (ultrasonic wave detection device) of the present embodiment is used by being mounted on the bottom of a fishing boat 10 (ship). The fish finder 11 is a device that detects an object A1 such as a fish school present in water, based on the ultrasonic waves W emitted by the ship (own ship) into the water.

  As shown in FIG. 2, the fish finder 11 includes a first ultrasonic sensor 21 and a second ultrasonic sensor 22 provided separately from the first ultrasonic sensor 21. Both ultrasonic sensors 21 and 22 are sensors having the same structure. However, the frequency band of the first ultrasonic sensor 21 is wider than the frequency band of the second ultrasonic sensor 22. More specifically, in the frequency band of the first ultrasonic sensor 21 of the present embodiment, the lower limit frequency (lower limit frequency f1) is, for example, 140 kHz, and the upper limit frequency (upper limit frequency f2) is, for example, 240 kHz. is there. In this case, the center frequency fm, which is an intermediate value between the lower limit frequency f1 and the upper limit frequency f2, is about 190 kHz, and the frequency bandwidth Δf, which indicates the difference between the lower limit frequency f1 and the upper limit frequency f2, is about 100 kHz. The ratio band Δf / fm, which indicates the ratio between the frequency band width Δf and the center frequency fm, is about 53%. On the other hand, the frequency band of the second ultrasonic sensor 22 of the present embodiment is a frequency range in which the lower limit frequency f1 is, for example, 180 kHz and the upper limit frequency f2 is, for example, 220 kHz. In this case, since the center frequency fm is about 200 kHz and the frequency bandwidth Δf is about 40 kHz, the specific bandwidth Δf / fm is about 20%.

  As shown in FIG. 3, the ultrasonic sensors 21 and 22 include an acoustic matching layer 23 and a piezoelectric element 24. The acoustic matching layer 23 is, for example, a disk-shaped resin-made plate-like material formed using glass epoxy (FR-4). In addition, the piezoelectric element 24 is, for example, a disk-shaped ceramic plate-like object formed by using lead zirconate titanate (PZT) which is piezoelectric ceramics. The piezoelectric element 24 has a front surface 25 bonded to the acoustic matching layer 23 and a back surface 26 opposite to the front surface 25. Further, a front surface side electrode layer (not shown) is formed on the front surface 25 of the piezoelectric element 24, and a back surface side electrode layer (not shown) is formed on the back surface 26 of the piezoelectric element 24. In this embodiment, the entire front surface 25 of the piezoelectric element 24 is bonded to the acoustic matching layer 23 via the front electrode layer and the adhesive layer (not shown).

  The ultrasonic sensors 21 and 22 are configured by housing the piezoelectric element 24 in the case 30. More specifically, the case 30 is made of a resin material such as ABS resin (acrylonitrile butadiene styrene resin) and has a bottomed cylindrical shape with one end open. The opening of the case 30 is closed by the acoustic matching layer 23 of the ultrasonic sensors 21 and 22.

  Further, as shown in FIG. 3, the first lead wire 31 is connected to the front side electrode layer of the piezoelectric element 24, and the second lead wire 32 is connected to the back side electrode layer of the piezoelectric element 24. There is. The first lead wire 31 is connected to a side terminal (not shown) extending outward from the front electrode layer by soldering or the like. The second lead wire 32 is connected to the outer peripheral portion of the back electrode layer by soldering or the like. Then, the first lead wire 31 and the second lead wire 32 are bound by the wiring tube 33 and drawn out of the case 30.

  Next, the electrical configuration of the fish finder 11 will be described.

  As shown in FIG. 4, the fish finder 11 includes a control device 40 that integrally controls the entire device. The control device 40 is composed of a well-known computer including a CPU 41, a ROM 42, a RAM 43, and the like. The CPU 41 is electrically connected to the first ultrasonic sensor 21 via the transmitting circuit 44 and electrically connected to the second ultrasonic sensor 22 via the receiving circuit 45. The transmission circuit 44 outputs an electric signal to the first ultrasonic sensor 21 to drive the first ultrasonic sensor 21. As a result, the first ultrasonic sensor 21 emits (transmits) the burst wave of the ultrasonic waves W as the transmission signal W1. Further, the second ultrasonic sensor 22 receives the reflected wave of the ultrasonic wave W as a reception signal W2. The reception circuit 45 receives an electric signal generated when the second ultrasonic sensor 22 receives the reception signal W2. Then, the electric signal input to the receiving circuit 45 is input to the CPU 41.

  The transmission signal W1 shown in FIG. 5 is defined by a plurality of types of parameters including the frequency f, the transmission interval L1, the amplitude L2, the burst length L3, and the sound pressure. The transmission interval L1 indicates the length from the start point of the first burst wave to the start point of the next burst wave. The burst length L3 indicates the length from the start point to the end point of one burst wave.

  Further, in the timer storage area of the RAM 43 shown in FIG. 4, various timers that are appropriately rewritten while the fish finder 11 is operating are stored (set). Further, in the random number storage area of the RAM 43, various random numbers used for determining parameters of the transmission signal W1 and the like are stored. Further, in the ROM 42, a transmission interval variation pattern distribution table (FIG. 6) in which a plurality of transmission interval variation patterns Pa-1 to Pa-8 indicating the variation (ms) of the transmission interval L1 of the transmission signal W1 are distributed. (Refer to) is stored.

  Then, the CPU 41 controls the transmission circuit 44 to emit the transmission signal W1 from the first ultrasonic sensor 21. Further, the CPU 41 receives, via the receiving circuit 45, the reception signal W2 that is generated when the second ultrasonic sensor 22 receives the reflected wave. When the reception signal W2 is input, the CPU 41 stores the reception information (parameter or the like) specified by the reception signal W2 in the storage area of the RAM 43.

  Further, the CPU 41 shown in FIG. 4 calculates the distance to the object A1 based on the time (arrival time t) from the transmission of the transmission signal W1 to the reception of the reception signal W2. Specifically, when the first ultrasonic sensor 21 starts transmitting the transmission signal W1, the CPU 41 sets (stores) a timer (0 ms) in the timer storage area of the RAM 43. Further, the CPU 41 adds the timer set at the start of transmission of the transmission signal W1 for each interrupt (for example, 4 ms). Then, when the second ultrasonic sensor 22 receives the reception signal W2, the CPU 41 stops the timer, calculates the product of the time (arrival time t) at that time point and the sound velocity of the ultrasonic wave W, and calculates the calculated product. One half of the above is set as a one-way distance to the object A1.

  Then, the CPU 41 changes the value of the transmission interval L1 (parameter) in the transmission signal W1 so as to have no regularity, based on the pattern selected by the random number lottery. That is, the CPU 41 has a function as "parameter changing means". Specifically, the CPU 41 performs a process of shortening the transmission interval L1 of the transmission signal W1 as the calculated distance is shorter, and a process of lengthening the transmission interval L1 of the transmission signal W1 as the calculated distance is longer. . In the present embodiment, the process of shortening the transmission interval L1 is performed when the calculated distance is less than 10 m, and the process of increasing the transmission interval L1 is performed when the calculated distance is 10 m or more. More specifically, when the calculated distance is less than 10 m, the CPU 41 is distributed to the transmission interval change amount pattern distribution table (see FIG. 6) based on the value of the transmission interval distribution random number acquired from the RAM 43. Among the transmission interval change amount patterns Pa-1 to Pa-8, a plurality of transmissions in which the change amount is negative (in the present embodiment, -0.1 ms, -0.2 ms, -0.3 ms, -0.4 ms). One transmission interval change amount pattern is determined from the interval change amount patterns Pa-1 to Pa-4. On the other hand, when the calculated distance is 10 m or more, the CPU 41, based on the value of the transmission interval distribution random number acquired from the RAM 43, the transmission interval change amount pattern Pa− that is distributed to the transmission interval change amount pattern distribution table. 1 to Pa-8, a plurality of transmission interval change amount patterns Pa-5 to Pa-8 in which the change amount is positive (+0.1 ms, +0.2 ms, +0.3 ms, +0.4 ms in the present embodiment). One of the transmission interval change amount patterns is determined from among the above. Then, the CPU 41 stores the determined transmission interval change amount pattern in the RAM 43. Further, the CPU 41 changes the value of the transmission interval L1 in the transmission signal W1 based on the amount of change in the transmission interval L1 indicated by the transmission interval change amount pattern stored in the RAM 43.

  Then, the CPU 41 shown in FIG. 4 determines whether or not the value of the transmission interval (that is, the reception interval) in the reception signal W2 changes in the same tendency in association with the change in the value of the transmission interval L1 in the transmission signal W1. To judge. Specifically, when the transmission interval L1 is shortened, the CPU 41 determines whether or not the reception interval indicated by the reception information stored in the RAM 43 becomes shorter in conjunction with the shorter transmission interval L1. . Even when the shortening amount of the reception interval is different from the shortening amount of the transmission interval L1, the CPU 41 determines that the value of the reception interval changes in the same tendency in association with the change of the value of the transmission interval L1. . On the other hand, when increasing the transmission interval L1, the CPU 41 determines whether or not the reception interval indicated by the reception information stored in the RAM 43 increases in conjunction with the increase in the transmission interval L1. Even when the extension amount of the reception interval is different from the extension amount of the transmission interval L1, the CPU 41 determines that the value of the reception interval changes in the same tendency in association with the change of the value of the transmission interval L1. .

  Then, when it is determined that the value of the reception interval changes in the same tendency in association with the change of the value of the transmission interval L1, the CPU 41 causes the reception signal W2 to be a reflected wave of the transmission signal W1 emitted by the ship. Presumed to be On the other hand, when it is determined that the value of the reception interval does not change in the same tendency in association with the change of the value of the transmission interval L1, the CPU 41 determines that the reception signal W2 is the reflected wave of the transmission signal W1 emitted by the ship. If not, it is excluded (that is, the received signal W2 is ignored as noise). That is, the CPU 41 has a function as "signal discrimination means".

  Further, the CPU 41 shown in FIG. 4 changes the value of the frequency f (parameter) in the transmission signal W1. Specifically, the CPU 41, in the reception signal W2 received by the second ultrasonic sensor 22, the reception signal W2 in which the value of the reception interval changes in the same tendency in association with the change in the value of the transmission interval L1. Is selected. Next, the CPU 41 compares the frequency f of the transmission signal W1 with the frequency f ′ of the selected reception signal W2. Then, when the frequency f ′ of the reception signal W2 is higher than the frequency f of the transmission signal W1, the CPU 41 performs the process of lowering the frequency f of the transmission signal W1 while the frequency f ′ of the reception signal W2 is the transmission signal W1. If the frequency f is lower than the frequency f, the process of increasing the frequency f of the transmission signal W1 is performed. Further, the CPU 41 sets the frequency f of the transmission signal W1 so that the second ultrasonic sensor 22 can receive the reception signal W2 near the center frequency fm (about 200 kHz in the present embodiment) where the sensitivity is maximum. Determine the change amount of.

  More specifically, Doppler shift occurs under the situation where the ship and the target A1 are relatively moving. Therefore, when the object A1 is approaching at the relative speed v, for example, the CPU 41 sets the frequency f ′ of the reception signal W2 as f ′ = f × (V + v) / (V−v) when the sound velocity is V. Calculated from the formula. If f = 180 kHz, V = 1500 m / s, and v = 10 m / s, then f′≈182.4 kHz. On the other hand, when the target A1 is moving away at the relative speed v, for example, the CPU 41 calculates the frequency f ′ from the formula of f ′ = f × (V−v) / (V + v). Under the same conditions as when the object A1 is approaching at the relative speed v, f′≈177.6 kHz.

  Next, the CPU 41 shown in FIG. 4 changes the frequency f of the transmission signal W1 used for the next transmission so as to cancel the Doppler shift. As described above, when the frequency f of the transmission signal W1 is 180 kHz and the frequency f ′ of the reception signal W2 is calculated to be about 182.4 kHz, that is, when the target A1 is approaching, the CPU 41 determines Then, control is performed to lower the frequency f of the transmission signal W1 by about 2.4 kHz so that the frequency f ′ of the reception signal W2 becomes 180 kHz. On the other hand, when the frequency f of the transmission signal W1 is 180 kHz and the frequency f ′ of the reception signal W2 is calculated to be about 177.6 kHz, that is, when the object A1 is moving away, the CPU 41 causes the reception signal Control is performed to increase the frequency f of the transmission signal W1 by about 2.4 kHz so that the frequency f ′ of W2 becomes 180 kHz.

  Then, the CPU 41 determines whether or not the value of the frequency f ′ in the reception signal W2 changes in the same tendency in association with the change in the value of the frequency f in the transmission signal W1. Specifically, when lowering the frequency f of the transmission signal W1, the CPU 41 determines that the frequency f ′ of the reception signal W2 indicated by the reception information stored in the RAM 43 is lower than the frequency f of the transmission signal W1. It is determined whether or not it will be lowered in conjunction with this. Even when the decrease amount of the frequency f ′ of the reception signal W2 is different from the decrease amount of the frequency f of the transmission signal W1, the CPU 41 interlocks with the change of the value of the frequency f of the transmission signal W1. It is determined that the values of f ′ are changing in the same tendency. On the other hand, when increasing the frequency f of the transmission signal W1, the CPU 41 increases the frequency f ′ of the reception signal W2 indicated by the reception information stored in the RAM 43 in association with the increase of the frequency f of the transmission signal W1. Or not. Even when the amount of increase in the frequency f ′ of the reception signal W2 is different from the amount of increase in the frequency f of the transmission signal W1, the CPU 41 interlocks with the change in the value of the frequency f of the transmission signal W1. It is determined that the values of f ′ are changing in the same tendency.

  When it is determined that the value of the frequency f ′ in the reception signal W2 changes in the same tendency in association with the change in the value of the frequency f in the transmission signal W1, the CPU 41 shown in FIG. It is estimated that W2 is a reflected wave of the transmission signal W1 emitted by the ship. After that, the CPU 41 continues the arithmetic processing on the reception signal W2 estimated to be the reflected wave of the transmission signal W1 emitted by the own ship. Specifically, the CPU 41 measures the time (arrival time t) from the transmission of the transmission signal W1 to the reception of the reception signal W2 by using the reception signal W2 determined to be linked to the transmission signal W1. . Then, the CPU 41 calculates the distance L from the own ship to the object A1 based on the measured arrival time t from the formula L = V × t / 2. Further, the CPU 41 uses the reception signal W2 determined to be linked to the transmission signal W1, and based on the frequency f of the transmission signal W1 and the frequency f ′ of the reception signal W2, the relative speed v between the ship and the target A1. Is calculated from the above Doppler shift equation (f ′ = f × (V + v) / (V−v) or f ′ = f × (V−v) / (V + v)).

  On the other hand, when it is determined that the value of the frequency f ′ in the reception signal W2 does not change in the same tendency in association with the change in the value of the frequency f in the transmission signal W1, the CPU 41 illustrated in FIG. It is determined that W2 is not a reflected wave of the transmission signal W1 emitted by the ship (that is, interference is occurring), and the reception signal W2 is eliminated (that is, the reception signal W2 is ignored as noise).

  Next, by repeatedly irradiating the ultrasonic wave W (transmission signal W1) into the water, the influence of the ultrasonic wave W3 (see FIG. 2) emitted by the other ship (other machine) is eliminated, and the own ship (fish finder 11) A method (ultrasonic wave detecting method) for detecting the object A1 (see FIG. 1) based on the ultrasonic wave W emitted by the user will be described. Here, the processing (arithmetic processing) performed by the CPU 41 of the control device 40 will be described. Note that this processing is executed based on the ultrasonic wave detection program. The ultrasonic wave detection program causes the CPU 41 to sequentially execute the parameter changing step, the transmitting step, the receiving step, and the signal determining step a plurality of times.

  First, the power (not shown) of the fish finder 11 is turned on. Next, in step S10 shown in FIG. 7, the CPU 41 determines the parameters of the transmission signal W1, specifically, the frequency f, the transmission interval L1 (see FIG. 5), the burst length L3 (see FIG. 5) and the sound pressure. The determination is made, and the process proceeds to step S20. In step S20, the CPU 41 controls to apply (output) a voltage (electrical signal) from the transmission circuit 44 to the first ultrasonic sensor 21 to drive the first ultrasonic sensor 21. As a result, the piezoelectric element 24 forming the first ultrasonic sensor 21 vibrates, and the burst wave of the ultrasonic wave W is emitted (transmitted) from the first ultrasonic sensor 21 to the water as the transmission signal W1.

  Then, when the transmission signal W1 reaches the object A1, the transmission signal W1 is reflected by the object A1 to become a reflected wave, propagates toward the fish finder 11, and is received as the reception signal W2 by the second ultrasonic sensor 22. Is input (received) to. After that, the reception signal W2 received by the second ultrasonic sensor 22 is converted into an electric signal and input to the CPU 41 via the reception circuit 45.

  In subsequent step S30, the CPU 41 determines whether or not the reception signal W2 received by the second ultrasonic sensor 22 includes a signal whose frequency f ′ (frequency f) and reception interval (transmission interval L1) are close to the transmission signal W1. Determine whether or not. In the present embodiment, the CPU 41 has a difference of frequency f (frequency f ′) from the transmission signal W1 of less than 5% and a difference of transmission interval L1 (reception interval) from the transmission signal W1 of less than 5%. It is determined whether there is the received signal W2. When there is no reception signal W2 close to the transmission signal W1 (step S30: NO), the CPU 41 shifts to the processing of step S40. In step S40, the CPU 41 performs a process of increasing the sound pressure of the transmission signal W1. Specifically, the CPU 41 increases the amplitude of the transmission signal W1 within the range of the capability of the control device 40 until the reception signal W2 close to the transmission signal W1 can be received.

  After that, the CPU 41 shifts to the processing of step S20. The process performed in the order of steps S20, S30, and S40 is repeated until the frequency f ′ (frequency f) and the reception interval (transmission interval L1) can receive the reception signal W2 close to the transmission signal W1. Then, when the reception signal W2 close to the transmission signal W1 can be received (step S30: YES), the CPU 41 selects a reflected wave to be noted at a relatively short distance among the reception waves targeted for the reception signal W2. Then, the amplitude of the transmission signal W1 is adjusted so that the amplitude of the received wave falls within a range suitable for signal processing. After that, the CPU 41 shifts to the processing of step S50.

  In step S50, the CPU 41 assumes that the reception signal W2 found in step S30 is a reflected wave of the transmission signal W1 from the own ship. Then, the CPU 41 measures the time (arrival time t) from the transmission of the transmission signal W1 to the reception of the reception signal W2, and based on the measured arrival time t, the distance L from the own ship to the object A1. To calculate.

  In the following step S60 (parameter changing step), the CPU 41 performs a process of changing the value of the transmission interval L1 (parameter) of the burst wave of the transmission signal W1. Specifically, the CPU 41 shortens the transmission interval L1 of the transmission signal W1 when the distance L to the object A1 is short (for example, less than 10 m). More specifically, the CPU 41, based on the value of the transmission interval distribution random number acquired from the RAM 43, the transmission interval change amount patterns Pa-1 to Pa distributed in the transmission interval change amount pattern distribution table (see FIG. 6). Among -8, one transmission interval change amount pattern is determined from a plurality of transmission interval change amount patterns Pa-1 to Pa-4 whose change amount is negative (-). Further, the CPU 41 lengthens the transmission interval L1 of the transmission signal W1 when the distance L to the object A1 is long (for example, 10 m or more). More specifically, the CPU 41 selects one of the transmission interval change amount patterns Pa-1 to Pa-8 distributed in the transmission interval change amount pattern distribution table based on the value of the transmission interval distribution random number acquired from the RAM 43. One transmission interval change amount pattern is determined from a plurality of transmission interval change amount patterns Pa-5 to Pa-8 in which the change amount is positive (+).

  In the following step S70 (transmission step), the CPU 41 transmits the burst wave with the transmission interval L1 changed as the transmission signal W1, and proceeds to the processing of step S80. In step S80 (reception step), the CPU 41 receives the reflected wave of the transmission signal W1 as the reception signal W2, and proceeds to the processing of step S90.

  In step S90 (signal determination step), the CPU 41 determines whether or not the value of the transmission interval (reception interval) in the reception signal W2 changes in the same tendency in association with the change in the value of the transmission interval L1. Specifically, when the transmission interval L1 is shortened in step S60, the CPU 41 determines whether or not the reception interval of the reception signal W2 becomes shorter in conjunction with the shorter transmission interval L1. On the other hand, when the transmission interval L1 is lengthened in step S60, the CPU 41 determines whether or not the reception interval of the reception signal W2 becomes longer as the transmission interval L1 becomes longer.

  When it is determined that the value of the reception interval of the reception signal W2 does not change in the same tendency in association with the change of the value of the transmission interval L1 (step S90: NO), the CPU 41 proceeds to the process of step S100. In step S100 (signal determination step), the CPU 41 determines that the non-interlocked reception signal W2 is not a reflected wave of the transmission signal W1 emitted by the ship and eliminates it (that is, ignores the reception signal W2 as noise). To do. In addition, when the interlocked reception signal W2 cannot be detected at all, the CPU 41 proceeds to the process of step S40.

  On the other hand, when it is determined in step S90 that the value of the reception interval of the reception signal W2 changes in the same tendency in association with the change of the value of the transmission interval L1 (step S90: YES), the CPU 41 determines that the reception signal W2 is changed. It is estimated that this is a reflected wave of the transmission signal W1 emitted by the own ship, and the process proceeds to step S110 shown in FIG. In step S110 (parameter changing step), the CPU 41 changes the parameter type of the transmission signal W1 used for determining the reception signal W2 from the transmission interval L1 to the frequency f. Then, the CPU 41 compares the frequency f of the transmission signal W1 with the frequency f ′ of the reception signal W2, and shifts to the processing of step S120.

  In step S120 (parameter changing step), the CPU 41 performs a process of changing the value of the frequency f (parameter) of the burst wave of the transmission signal W1. Specifically, the CPU 41 lowers the frequency f of the transmission signal W1 when the frequency f ′ of the reception signal W2 is higher than the frequency f of the transmission signal W1. In addition, the CPU 41 increases the frequency f of the transmission signal W1 when the frequency f ′ of the reception signal W2 is lower than the frequency f of the transmission signal W1. In addition, Doppler shift occurs under the situation where the ship and the target A1 are relatively moving. Therefore, when the object A1 is approaching at the relative speed v, for example, the CPU 41 sets the frequency f ′ of the reception signal W2 as f ′ = f × (V + v) / (V−v) when the sound velocity is V. Calculated from the formula. In this case, the calculated frequency f ′ is higher than the frequency f of the transmission signal W1. Then, the CPU 41 changes the frequency f of the transmission signal W1 so as to cancel the Doppler shift. Specifically, the CPU 41 controls to lower the frequency f of the transmission signal W1 so that the frequency f ′ of the reception signal W2 becomes equal to the frequency f of the transmission signal W1 at the present time.

  On the other hand, when the object A1 is moving away at the relative speed v, for example, the CPU 41 calculates the frequency f ′ of the reception signal W2 from the formula of f ′ = f × (V−v) / (V + v). In this case, the calculated frequency f'is smaller than the frequency f. Then, the CPU 41 performs control to increase the frequency f of the transmission signal W1 so that the frequency f ′ of the reception signal W2 becomes equal to the frequency f of the transmission signal W1 at the present time.

  In the following step S130 (transmission step), the CPU 41 transmits the burst wave with the frequency f changed as the transmission signal W1, and proceeds to the processing of step S140. In step S140 (reception step), the CPU 41 receives the reflected wave of the transmission signal W1 as the reception signal W2, and proceeds to the processing of step S150.

  In step S150 (signal determination step), the CPU 41 determines whether or not the value of the frequency f ′ in the reception signal W2 changes in the same tendency in association with the change in the value of the frequency f in the transmission signal W1. Specifically, when the frequency f of the transmission signal W1 is lowered in step S120, the CPU 41 lowers the frequency f ′ of the reception signal W2 in conjunction with the reduction of the frequency f of the transmission signal W1. Determine whether or not. On the other hand, when the frequency f of the transmission signal W1 is increased in step S120, the CPU 41 determines whether or not the frequency f ′ of the reception signal W2 increases in conjunction with the increase of the frequency f of the transmission signal W1. To do.

  Then, when it is determined that the value of the frequency f ′ of the reception signal W2 does not change in the same tendency in association with the change of the value of the frequency f in the transmission signal W1 (step S150: NO), the CPU 41 performs the process of step S160. Move to. In step S160 (signal determination step), the CPU 41 determines that the non-interlocked reception signal W2 is not a reflected wave of the transmission signal W1 emitted by the ship and eliminates it (that is, ignores the reception signal W2 as noise). To do. After that, the CPU 41 ends the processing here.

  On the other hand, when it is determined in step S150 that the frequency f ′ of the reception signal W2 changes in the same tendency in association with the change of the value of the frequency f in the transmission signal W1 (step S150: YES), the CPU 41 causes the reception signal It is determined that W2 is a reflected wave of the transmission signal W1 emitted by the ship. At this point, the object A1 is detected. That is, in the present embodiment, the parameter changing step (step S60 or step S120), the transmitting step (step S70 or step S130), the receiving step (step S80 or step S140) and the signal determining step (step S90, S100 or step S150, The object A1 is detected by sequentially repeating S160) twice.

  In the following step S170, the CPU 41 measures the time (arrival time t) from the transmission of the transmission signal W1 to the reception of the reception signal W2 by using the reception signal W2 determined to be linked to the transmission signal W1. The distance L from the ship to the object A1 is calculated based on the measured arrival time t. In the following step S180, the CPU 41 calculates the relative speed v based on the difference between the frequency f of the transmission signal W1 and the frequency f ′ of the reception signal W2 using the reception signal W2 determined to be linked to the transmission signal W1. . In subsequent step S190, the CPU 41 performs feedback regarding a desired operation (capture of the target object A1 such as a school of fish in the present embodiment) based on the calculated distance L to the target object A1 and the relative speed v. For example, when the distance L is short and the relative speed v is small, the risk of collision with another ship is high. Therefore, by shortening the transmission interval L1 of the transmission signal W1, the reception interval (observation interval) of the reception signal W2 is shortened. To do. Then, the CPU 41 ends the processing here.

  Thereafter, when the worker turns off the power, the control device 40 stops the transmission circuit 44 and the reception circuit 45, and the irradiation of the transmission signal W1 and the reception of the reception signal W2 are completed.

  If it is determined in step S150 that the frequency f ′ of the reception signal W2 changes in the same tendency in association with the change of the value of the frequency f in the transmission signal W1 (step S150: YES), it is necessary. In this case (if there is still a suspicion of interference), the burst length L3 value may be changed. In this case, the CPU 41 performs step S210 (parameter changing step) immediately after step S150, and performs processing for changing the burst length L3 of the transmission signal W1. By the way, the burst length of the reception signal W2 becomes longer than the burst length L3 of the transmission signal W1 due to factors such as the occurrence of reverberation, the presence of a plurality of objects A1 near the ship, and the spread of the propagation path of the ultrasonic waves W. Often occurs. Therefore, in the present embodiment, when the burst length of the reception signal W2 is longer than the previously recognized reverberation length as compared with the burst length L3 of the transmission signal W1, the CPU 41 shortens the burst length L3. Perform processing to By doing so, even when there are a plurality of objects A1, it is possible to try to separate the reception signal W2 (reflected wave). If possible, the CPU 41 changes the burst length L3 of the transmission signal W1 within the range where the reflected waves can be separated.

  In the following step S220 (transmission step), the CPU 41 transmits the burst wave in which the burst length L3 is changed as the transmission signal W1, and shifts to the processing in step S230. In step S230 (reception step), the CPU 41 receives the reflected wave of the transmission signal W1 as the reception signal W2, and proceeds to the processing of step S240.

  In step S240 (signal determination step), the CPU 41 determines whether or not the burst length value in the reception signal W2 changes in the same tendency in association with the change in the burst length L3 value in the transmission signal W1. When it is determined that the burst length value of the reception signal W2 does not change in the same tendency in association with the change of the burst length L3 of the transmission signal W1 (step S240: NO), the CPU 41 performs the process of step S160. Move to. On the other hand, when it is determined that the burst length of the reception signal W2 changes in the same tendency in association with the change of the value of the burst length L3 of the transmission signal W1 (step S240: YES), the CPU 41 shifts to the processing of step S170. .

  Therefore, according to this embodiment, the following effects can be obtained.

  (1) In the fish finder 11 of this embodiment, the CPU 41 randomly changes the value of the parameter (transmission interval L1) in the transmission signal W1. Therefore, even if there is another fishing boat (another ship) that changes the parameter of the transmission signal in the same modification mode as the parameter of the transmission signal W1 of the own ship, the parameter of the transmission signal W1 of the own ship is transmitted to the other ship. It can be different than the signal parameters. In this case, the CPU 41 determines whether or not the reception interval of the reception signal W2 changes in the same tendency in association with the change of the transmission interval L1 of the transmission signal W1, so that the reception signal W2 is emitted by the ship. It is possible to reliably determine whether or not it is the reflected wave of the transmission signal W1. As a result, it is possible to prevent interference with a transmission signal emitted by another ship.

  (2) In the present embodiment, two types of parameter value interlock determination are performed by changing the parameter type (specifically, the reception interval of the reception signal W2 tends to have the same tendency in association with the change of the transmission interval L1 of the transmission signal W1. And whether or not the frequency f ′ of the reception signal W2 changes in the same tendency in conjunction with the change of the frequency f of the transmission signal W1). Only when the determination results of both determinations are affirmative, the received signal W2 is determined to be the reflected wave of the transmitted signal W1 emitted by the ship. As a result, the received signal W2 can be determined more accurately than in the case where the determination of the parameter is performed in only one step, so that it is possible to reliably prevent interference with the transmitted signal generated by another ship.

  (3) In the related art described in Patent Document 4, "the noise is distinguished from the received signal reflected by the moving body by switching the transmission frequency of the ultrasonic signal. An "identification means" is disclosed. However, under a situation in which a plurality of moving bodies are mounted with the same ultrasonic wave detection device (ultrasonic wave sensor) to perform sensing, interference cannot be avoided. Because the Doppler shift occurs under the condition that each moving body is relatively moving, the received ultrasonic wave is an ultrasonic wave whose frequency is switched or an ultrasonic wave which is affected by the Doppler shift. This is because it is difficult to determine whether In this case, there is a problem that a transmission signal emitted by another device is erroneously determined as a reflected wave of the transmission signal emitted by the own device.

  On the other hand, in the present embodiment, if the parameter value of the reception signal W2 is not linked to the change of the parameter value of the transmission signal W1, regardless of whether the reception signal W2 is affected by the Doppler shift, It is possible to determine that the received signal W2 is not a reflected wave of the transmitted signal W1 emitted by the ship and eliminate it. Therefore, it is possible to reliably prevent interference with the transmission signal emitted by another ship.

  (4) In Patent Document 5, a reflected wave of a transmission signal of its own device is provided by assigning an ID number to an ultrasonic wave (transmission signal) to be transmitted or performing FM modulation (frequency modulation) on the transmission signal. A technique for making it easier to distinguish the received signal) is disclosed. It should be noted that the method of discriminating the reflected wave using the ID number is similar to, for example, the idea of “recognizing the reflected wave that matches the key prepared in advance as the reflected wave of the transmission signal of the own device”. I can say. However, since the number of keys is finite, it is difficult to distinguish many reflected waves. Further, in Patent Document 5, since it is necessary to perform complex signal processing such as FM modulation, the transmission / reception circuit becomes large, and the ultrasonic detection device tends to be expensive and heavy.

  On the other hand, the ultrasonic detection device (fish finder 11) of the present embodiment only needs to change the values of the parameters (transmission interval L1, frequency f, etc.) originally specified in the transmission signal W1, and the reflected wave (reception signal). Since the determination of W2) is performed, it is not necessary to assign an ID number or perform complicated signal processing. Therefore, the ultrasonic detection device can be manufactured at a relatively low cost, and the weight of the ultrasonic detection device can be reduced. Therefore, the ultrasonic detection device of this embodiment is suitable for mounting on an aerial drone that moves in the air.

  (5) In the present embodiment, the ultrasonic sensor that transmits and receives the ultrasonic wave W is divided into a first ultrasonic sensor 21 that transmits the transmission signal W1 and a second ultrasonic sensor 22 that receives the reception signal W2. ing. In this case, since the second ultrasonic sensor 22 can receive the signal even when the transmission signal W1 is transmitted from the first ultrasonic sensor 21, the reflected wave of the transmission signal W1 is directly received as the reception signal W2. Therefore, it is possible to reliably perform the parameter comparison (comparison between the transmission interval L1 and the reception interval, comparison between the frequency f and the frequency f ′) between the transmission signal W1 and the reception signal W2. Further, even if the characteristics of the ultrasonic sensors 21 and 22 change due to changes in the environment or deterioration over time, the parameters themselves can be compared, and therefore erroneous determination due to changes in the characteristics can be prevented.

[Second Embodiment]
A second embodiment of the present invention will be described below with reference to the drawings. Here, the description will focus on the parts that are different from the first embodiment. In this embodiment, the mode of changing the value of the frequency f is different from that in the first embodiment.

  More specifically, in the fish finder 11 of the present embodiment, both the frequency band of the first ultrasonic sensor 21 and the frequency band of the second ultrasonic sensor 22 have a lower limit frequency f1 of 140 kHz and an upper limit frequency f2 of 240 kHz. The frequency range is Further, in the ROM 42 of the control device 40, a frequency change amount pattern distribution table in which a plurality of frequency change amount patterns Pb-1 to Pb-8 indicating the change amount (kHz) of the frequency f of the transmission signal W1 is distributed (FIG. 9) is stored.

  By the way, although the process of step S150 (see FIG. 8) is performed in the first embodiment, there is a reception signal W2 that cannot be identified as a reflected wave of the transmission signal W1 emitted by the own ship, and the reception thereof is received. The value of the frequency f ′ of the signal W2 may be close to the value of the frequency f of the transmission signal W1. In this case, the CPU 41 of the present embodiment changes the value of the frequency f (parameter) in the transmission signal W1 so as to have no regularity between 160 kHz and 220 kHz based on the pattern selected by random number lottery, for example.

  Specifically, the CPU 41, based on the value of the random number for frequency distribution acquired from the RAM 43, allocates a plurality of frequency change patterns Pb-1 to Pb-1 to the frequency change pattern distribution table (see FIG. 9). One frequency variation pattern is determined from Pb-8. Then, the CPU 41 stores the determined frequency change amount pattern in the RAM 43. Further, the CPU 41 changes the value of the frequency f in the transmission signal W1 based on the amount of change in the frequency f indicated by the frequency change amount pattern stored in the RAM 43.

  Next, the CPU 41 determines whether or not the value of the frequency f ′ in the reception signal W2 changes in the same tendency in association with the change in the value of the frequency f in the transmission signal W1. Then, when it is determined that the value of the frequency f ′ changes in the same tendency in association with the change of the value of the frequency f, the CPU 41 determines that the reception signal W2 is the reflected wave of the transmission signal W1 emitted by the ship. Presumed to be On the other hand, when it is determined that the value of the frequency f ′ does not change in the same tendency in association with the change of the value of the frequency f, the CPU 41 determines that the reception signal W2 is the reflected wave of the transmission signal W1 emitted by the ship. If not, it is excluded (that is, the received signal W2 is ignored as noise).

[Third Embodiment]
A third embodiment of the present invention will be described below with reference to the drawings. Here, the description will focus on the parts that are different from the first embodiment. In this embodiment, the electrical configuration of the fish finder is different from that of the first embodiment.

  More specifically, as shown in FIG. 10, in the fish finder 51 (ultrasonic wave detection device) of the present embodiment, the CPU 53 of the control device 52 (computer) functions as the learning unit 54 and the change operation execution unit 55. have. Further, the RAM 56 of the control device 52 has a function as the storage unit 57.

  Further, the learning unit 54 learns a method of shortening the time (discrimination time) required to discriminate the reception signal W2 based on the type of parameter of the transmission signal W1 and the changing mode of the value. For example, the learning unit 54 uses which parameter among a plurality of types of parameters (frequency f, transmission interval L1, amplitude L2, burst length L3, sound pressure, etc.) that define the transmission signal W1, and to what extent the swing width is. It is learned whether the discrimination time T1 can be shortened by changing the (variation amount). More specifically, first, the learning unit 54 selects one parameter from a plurality of types of parameters. Next, the learning unit 54 sets the timer (0 ms) in the timer storage area of the RAM 56 (stores) at the start of the parameter changing step (see steps S60 and S120 of FIGS. 7 and 8) for changing the value of the selected parameter. ) Do. Further, the learning unit 54 adds the timer set at the start of the parameter changing step for each interrupt (for example, 4 ms). Thereafter, the transmission step (see steps S70 and S130), the reception step (see steps S80 and S140), and the signal determination step (see steps S90 and S150) are sequentially performed on the transmission signal W1 with the parameter value changed. Let Then, at the end of the signal determination step, the learning unit 54 stops the timer and measures the time (discrimination time T1) at that time. After that, the learning unit 54 can obtain the learning result G1 about “which parameter should be used to shorten the discrimination time T1” by measuring the discrimination time T1 for each parameter.

  Further, in which order among the plurality of types of parameters described above, the learning unit 54 shown in FIG. 10 can determine the parameters to shorten the time required to determine the received signal W2 (determination time T2). To learn. More specifically, first, the learning unit 54 selects one parameter (for example, the transmission interval L1) from a plurality of types of parameters. Next, the learning unit 54 causes the parameter changing step, the transmitting step, the receiving step, and the signal determining step to be executed in order for the selected parameter. Further, the learning unit 54 sets (stores) a timer (0 ms) in the timer storage area of the RAM 56 at the start of the parameter changing step, and adds the set timer for each interrupt (for example, 4 ms).

  After the completion of the first signal determination step, the learning unit 54 selects a parameter (for example, frequency f) different from the previously selected parameter from the plurality of types of parameters, and also regarding the selected another parameter, The parameter changing step, the transmitting step, the receiving step, and the signal determining step are executed in order. Then, at the end of the second signal discrimination step, the learning unit 54 stops the timer and measures the time (discrimination time T2) at that time. After that, the learning unit 54 causes the parameter changing step, the transmitting step, the receiving step, and the signal determining step to be executed in order even in another combination (for example, the first time: the burst length L3, the second time: the transmission interval L1, etc.), and makes a determination Measure time T2. As a result, it is possible to obtain the learning result G2 regarding "in what order should the parameters be determined to reduce the determination time T2".

  Further, the learning unit 54 shown in FIG. 10 learns how to change the value of the parameter for each parameter so as to shorten the time (determination time T3) required to determine the reception signal W2. . More specifically, first, the learning unit 54 selects one parameter (here, the frequency f) from a plurality of types of parameters. Next, the learning unit 54 performs a parameter changing step to increase the value of the selected parameter. Further, the learning unit 54 sets (stores) a timer (0 ms) in the timer storage area of the RAM 56 at the start of the parameter changing step, and adds the set timer for each interrupt (for example, 4 ms). Further, the learning unit 54 sequentially executes the transmission step, the reception step, and the signal determination step. Then, at the end of the signal determination step, the learning unit 54 stops the timer and measures the time at that point (determination time T3).

  Next, the learning unit 54 reduces the value of the selected parameter (here, the frequency f) in the parameter changing step, and then sequentially executes the transmitting step, the receiving step, and the signal determining step to measure the determining time T3. To do. Then, the learning unit 54 compares the measured time T3 when the parameter value is increased with the measured time T3 when the parameter value is decreased. As a result, the learning unit 54 can obtain the learning result G3 regarding "how to change the value of the parameter to shorten the determination time T3". The learning unit 54 also measures the discrimination time T3 for different parameters (transmission interval L1, amplitude L2, burst length L3, sound pressure, etc.) when the parameter value is increased and when it is decreased, and both parameters are measured. The learning result G3 can be obtained by comparing In this embodiment, the signal determination step (see steps S90 and S150) for confirming whether or not the parameters are interlocked with each other is performed, but the information on whether or not the erroneous determination in the signal determination step is corrected is also acquired. However, it may be included in the learning result.

  The learning unit 54 shown in FIG. 10 stores data indicating the obtained learning results G1 to G3 in the storage unit 57. Then, the change operation execution unit 55 determines the change mode of the parameter type and the value based on the learning results G1 to G3 stored in the storage unit 57, and the change operation by the CPU 53 is performed according to the determined contents. Let it be done.

  Therefore, according to the present embodiment, the mode of changing the type and value of the parameter of the transmission signal W1 is optimized based on the learning results G1 to G3 by the learning unit 54. By changing the parameter of W1, it is possible to surely shorten the time required to determine the reception signal W2. Moreover, if the learning section 54 increases the number of learning opportunities, the mode of changing the parameter of the transmission signal W1 is further optimized, and thus the time required to determine the reception signal W2 can be further shortened.

[Fourth Embodiment]
Hereinafter, a fourth embodiment embodying the present invention will be described with reference to the drawings. Here, the description will focus on the parts that are different from the third embodiment. In this embodiment, the electrical configuration of the fish finder is slightly different from that of the third embodiment.

  More specifically, as shown in FIG. 11, in the fish finder 61 (ultrasonic wave detection device) of the present embodiment, the CPU 63 of the control device 62 (computer) has a function as the change operation execution unit 64. However, it does not have the function as the learning unit 54 of the third embodiment. Further, the RAM 65 of the control device 62 has a function as a storage unit 66. The storage unit 66 stores in advance learned data indicating the same learning result as the learning results G1 to G3 of the third embodiment. Then, the change operation execution unit 64 determines the type of parameter and the change mode of the value based on the learning result stored in the storage unit 66, and causes the CPU 63 to perform the change operation according to the determined content.

  Therefore, according to the present embodiment, the mode of changing the type and value of the parameter of the transmission signal W1 is optimized based on the learning result stored in the storage unit 66, and the transmission is performed according to the optimized content. By changing the parameter of the signal W1, it is possible to surely shorten the time required to determine the received signal W2.

  The above embodiments may be modified as follows.

  In the above embodiment, the value of the parameter (transmission interval L1) of the transmission signal W1 is changed so as to have no regularity, while the type of parameter of the transmission signal W1 is changed regularly (transmission interval L1 → frequency f). However, the parameter value of the transmission signal W1 may be changed so as not to have regularity, while the parameter value of the transmission signal W1 may be changed regularly. Further, both the type and the value of the parameter in the transmission signal W1 may be changed so that there is no regularity.

  In the above-described embodiment, whether or not the reception signal W2 is a reflected wave of the transmission signal W1 emitted by the own ship is performed by performing the process of changing the transmission interval L1 of the transmission signal W1 and the frequency f of the transmission signal W1. Was determined. However, by changing at least one of the process of changing the transmission interval L1 and the process of changing the frequency f to the process of changing the amplitude L2, the burst length L3, the sound pressure, etc. of the transmission signal W1, the reception signal W2 is automatically changed. You may determine whether it is the reflected wave of the transmitted signal W1 which the ship emitted. Further, in addition to the process of changing the transmission interval L1 and the process of changing the frequency f, at least one of the process of changing the amplitude L2, the process of changing the burst length L3, and the process of changing the sound pressure is performed. It may be determined whether the received signal W2 is a reflected wave of the transmitted signal W1 emitted by the ship.

  In the above-described embodiment, after performing the processes of steps S50 to S100 (the process of changing the transmission interval L1 and determining whether the reception interval of the reception signal W2 also changes in association with the change), step S110. The processes from S160 to S160 (the process of changing the frequency f and determining whether or not the frequency f'of the received signal W2 also changes in association with the change) are performed. However, the processes of steps S50 to S100 may be performed after the processes of steps S110 to S160.

  In the above embodiment, when the distance L to the object A1 is short (for example, less than 10 m), the transmission interval L1 of the transmission signal W1 is shortened, and when the distance L to the object A1 is long (for example, 10 m or more). In the above case), the process of increasing the transmission interval L1 of the transmission signal W1 (see step S60 in FIG. 7) was performed. However, in step S60, even if the transmission interval L1 is significantly shortened when the distance L to the object A1 is short, and the transmission interval L1 is slightly shortened when the distance L to the object A1 is long, Good. In addition, in step S60, even if the transmission interval L1 is slightly lengthened when the distance L to the object A1 is short, and the transmission interval L1 is significantly lengthened when the distance L to the object A1 is long, Good. Further, in step S60, the transmission interval L1 may be lengthened when the distance L to the object A1 is short, and the transmission interval L1 may be shortened when the distance L to the object A1 is long. However, when the target A1 is not a school of fish but another ship (another machine), it is preferable to shorten the transmission interval L1 of the transmission signal W1 when the distance L to the target A1 is short. By doing so, the reception interval of the reception signal W2 is shortened, so that the reception signal W2 can be quickly discriminated, and the operation for avoiding a collision with another ship can be swiftly performed based on the discrimination result. it can. As a result, the risk of collision with another ship is reduced.

  In the above embodiment, a process of shortening the transmission interval L1 of the transmission signal W1 when the distance L to the target A1 is short and lengthening the transmission interval L1 of the transmission signal W1 when the distance L to the target A1 is long. (See step S60 in FIG. 7). However, in step S50, the amplitude of the reception signal W2 is measured, and in step S60, when the amplitude of the reception signal W2 is large, the amplitude L2 (see FIG. 5) of the transmission signal W1 is reduced and the amplitude of the reception signal W2 is small. In that case, a process of increasing the amplitude L2 of the transmission signal W1 may be performed. With this configuration, the amplitude L2 of the transmission signal W1 is controlled so that the amplitude of the reception signal W2, which is the reflected wave of the transmission signal W1 of interest, has a magnitude suitable for signal processing. In this case, in the receiving circuit 45, which is a processing circuit for the received signal W2, the variable range of the amplification factor of the received signal W2 can be made relatively small, and the dynamic range of AD conversion can be made relatively small, so that it is low. A cost receiver circuit 45 can be employed. Further, when the amplitude of the reception signal W2 is large, the amplitude L2 of the transmission signal W1 is reduced, so that unnecessary noise can be suppressed from being dissipated and use of energy more than necessary can be suppressed. On the contrary, when the amplitude of the reception signal W2 is small, the amplitude L2 of the transmission signal W1 is increased in order to avoid the calculation processing with the weak reception signal W2, and therefore the CPU 41 must reliably determine the reception signal W2. You can

  -In the said embodiment, you may perform the process which lowers the frequency f of the transmission signal W1 when the distance L to the target object A1 is short. That is, when the distance L to the object A1 becomes shorter, the frequency f ′ of the reception signal W2 becomes higher due to the Doppler shift, so the frequency f of the transmission signal W1 may be lowered so as to cancel the Doppler shift. By doing so, the frequency f ′ of the reception signal W2 can be made constant, and the frequency f ′ of the reception signal W2 can be aligned near the center frequency fm of the second ultrasonic sensor 22, so that the reception signal It is possible to prevent the frequency f ′ of W2 from deviating from the frequency band of the second ultrasonic sensor 22. Moreover, since it is sufficient to prepare the second ultrasonic sensor 22 having a relatively narrow frequency band, the manufacturing cost of the second ultrasonic sensor 22 can be suppressed.

  In the above embodiment, the sound pressure of the transmission signal W1 is reduced when the distance L to the object A1 is short, and the sound pressure of the transmission signal W1 is increased when the distance L to the object A1 is long. May be. With this configuration, the sound pressure of the reception signal W2 at the time of reception by the second ultrasonic sensor 22 becomes constant.

  In the above embodiment, the reception determination step of determining whether or not the second ultrasonic sensor 22 has received the reception signal W2 may be performed at the timing between step S20 and step S30. Then, when it is determined that the second ultrasonic sensor 22 does not receive the reception signal W2, the parameter changing step (steps S60, S120, S210), the transmitting step (steps S70, S130, S220), the receiving step (Steps S80, S140, S230) and the signal determination step (Steps S90, S100, S150, S160, S240) may not be performed.

  In the above embodiment, the CPU 41 compares the time-series change amount ΔL of the distance L (see step S170 of FIG. 8) with the distance change amount calculated from the relative speed v (see step S180 of FIG. 8). You may perform the process to do. In this case, whether or not there is a measurement error is determined by determining whether or not the change amount ΔL deviates from the distance change amount (that is, whether or not the value of the change amount ΔL is substantially equal to the value of the distance change amount). Can be determined. The distance change amount is obtained by the product of the relative speed v and the elapsed time Δt.

  The learning unit 54 of the third embodiment learns a method of shortening the time required to determine the reception signal W2 based on the type of change of the parameter and the value of the transmission signal W1. May be learned. For example, the learning unit 54 may learn a method of accurately determining the reception signal W2. More specifically, the learning unit 54 determines which of the plural types of parameters (frequency f, transmission interval L1, amplitude L2, burst length L3, sound pressure, etc.) that define the transmission signal W1 as the reception signal W2. It may be one that learns whether it can be accurately determined. In addition, the learning unit 54 may learn the order in which the parameter of the plurality of types of parameters should be determined to accurately determine the reception signal W2. Further, the learning unit 54 may learn how to change (for example, add or subtract) the value of the parameter for each parameter to accurately determine the reception signal W2.

  In the control device 52 of the third embodiment, the CPU 53 has the functions of the learning unit 54 and the change operation execution unit 55, and the RAM 56 has the function of the storage unit 57. However, the CPU of the control device other than the control device 52 may have the functions of the learning unit 54 and the change operation executing unit 55, or the RAM of the control device different from the control device 52 is the storage unit. It may have the function of 57. Similarly, in the control device 62 of the fourth embodiment, the CPU 63 has a function as the changing operation executing unit 64, and the RAM 65 has a function as the storing unit 66. However, the CPU of the control device different from the control device 62 may have the function as the variation operation execution unit 64, and the RAM of the control device different from the control device 62 may have the function as the storage unit 66. You may have.

  In the fourth embodiment, the storage unit 66 stores in advance the learned data indicating the same learning result as the learning results G1 to G3 of the third embodiment. However, the learned data may be transmitted to the control device 62 via communication means such as Bluetooth (registered trademark of Bluetooth SIG, Incorporated), infrared communication, internet line (telephone line, etc.). The learned data may be transmitted to the control device 62 by connecting a USB (Universal Serial Bus) flash memory or the like to a USB terminal provided in the control device 62, or may be transmitted to the control device 62 electrically. It may be transmitted to the control device 62 by mounting an IC card (integrated circuit card) on the IC card reader / writer connected electrically.

  In the first embodiment, the frequency band of the first ultrasonic sensor 21 is wider than the frequency band of the second ultrasonic sensor 22. In the second embodiment, the frequency band of the first ultrasonic sensor 21 is the same as the frequency band of the second ultrasonic sensor 22. However, the frequency band of the first ultrasonic sensor 21 may be narrower than the frequency band of the second ultrasonic sensor 22. Further, an amplification circuit is provided in the reception circuit 45 to which an electric signal generated when the reception signal W2 is received by the second ultrasonic sensor 22 is input, and the amplification factor is adjusted according to the level of the reception signal W2. You may adjust.

  In each of the above-described embodiments, the ultrasonic sensor includes the first ultrasonic sensor 21 that transmits the transmission signal W1 and the second ultrasonic sensor 22 that receives the reception signal W2. However, the ultrasonic sensor may be one ultrasonic sensor having the function of transmitting the transmission signal W1 and the function of receiving the reception signal W2.

  In each of the above-described embodiments, the fish finder 11, 51, 61 that does not change the irradiation direction of the ultrasonic wave W is used as the ultrasonic detection device, but the sonar that changes the irradiation direction of the ultrasonic wave W is ultrasonically detected. It may be used as a device. When the irradiation direction of the ultrasonic wave W is changed, the detection range of the object A1 can be widened. Further, although the ultrasonic detection device of each of the above-described embodiments is mounted on the fishing boat 10 and used, it may be mounted on another boat such as a marine exploration boat and used. Furthermore, the ultrasonic detection device may be mounted on a moving body other than a ship, such as an aerial drone, an underwater drone, an automobile, or the like. Although the target A1 in each of the above-described embodiments is a school of fish, the target may be another moving body (another machine).

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiment will be listed below.

  (1) In any one of claims 1 to 9, the parameter changing unit indicates a change amount of at least one of a change amount of a frequency of the transmission signal and a change amount of a transmission interval of the transmission signal. An ultrasonic detection device, characterized in that it is determined by selecting one pattern from a plurality of patterns, and the value of the parameter is changed based on the determined amount of change.

  (2) In claim 10, each time the type of the parameter is changed in the parameter changing step, the value of the parameter in the received signal has the same tendency in the signal determining step in association with the change in the value of the parameter. It is characterized in that the received signal is determined to be a reflected wave of the transmission signal generated by itself, when the determination results of all the determinations are affirmative. Ultrasonic detection method.

  (3) In claim 10, in the case where it is determined that the ultrasonic sensor has not received the reception signal, a reception determination step of determining whether the ultrasonic sensor has received the reception signal is performed. The ultrasonic detecting method is characterized in that the parameter changing step, the transmitting step, the receiving step, and the signal determining step are not performed.

11, 51, 61 ... Fish finder 21 as ultrasonic detecting device ... First ultrasonic sensor 22 as ultrasonic sensor ... Second ultrasonic sensor 40, 52, 62 as ultrasonic sensor ... Computer Control devices 41, 53, 63 ... CPU as parameter changing means and signal determining means
54 ... Learning unit 57, 66 ... Storage unit 55, 64 ... Change operation executing unit A1 ... Object f ... Transmission signal frequency f '... Received signal frequency fm ... Center frequencies G1 to G3 ... Learning result L ... Object Distance L1 ... Transmission interval L2 ... Amplitude L3 ... Burst length W ... Ultrasonic wave W1 generated by the device itself ... Transmitted signal W2 ... Received signal W3 ... Ultrasonic wave generated by another device

Claims (11)

A device that eliminates the influence of ultrasonic waves emitted by other devices by repeatedly irradiating ultrasonic waves, and detects an object based on the ultrasonic waves emitted by itself.
An ultrasonic sensor that transmits, as a transmission signal, a burst wave of ultrasonic waves defined by a plurality of types of parameters including frequency, transmission interval, amplitude, and burst length, and an ultrasonic sensor that receives the reflected wave as a reception signal,
Parameter changing means for changing the type and value of the parameter in the transmission signal a plurality of times,
It is determined whether or not the value of the parameter in the received signal changes in the same tendency in association with the change in the value of the parameter, and the received signal in the case of non-interlocking of the transmitted signal of its own device An ultrasonic wave detection device, comprising: a signal discriminating means that discriminates that the wave is not a reflected wave and eliminates it.   The ultrasonic detecting apparatus according to claim 1, wherein the parameter changing unit changes at least one of the type and the value of the parameter in the transmission signal so as to have no regularity. A learning unit that learns a method for shortening the time required to determine the received signal based on the type of the parameter of the transmission signal and the manner of changing the value of the parameter;
A storage unit for storing the learning result by the learning unit;
A change operation execution unit that determines a change mode of the type and value of the parameter based on the learning result stored in the storage unit, and causes the parameter change unit to perform a change operation according to the determined content; The ultrasonic detection device according to claim 1 or 2, further comprising: A storage unit that stores in advance a learning result obtained by learning a method for shortening the time required to determine the received signal based on the change type of the parameter and the value of the transmission signal;
A change operation execution unit that determines a change mode of the type and value of the parameter based on the learning result stored in the storage unit, and causes the parameter change unit to perform a change operation according to the determined content; The ultrasonic detection device according to claim 1 or 2, further comprising:   The parameter changing means calculates the distance to the object based on the time from the transmission of the transmission signal to the reception of the reception signal, and the shorter the distance, the shorter the transmission interval of the transmission signal. However, the ultrasonic detection device according to any one of claims 1 to 4, wherein the transmission interval of the transmission signal is set longer as the distance is longer.   The parameter changing means decreases the amplitude of the transmission signal when the amplitude of the reception signal is large, and increases the amplitude of the transmission signal when the amplitude of the reception signal is small. The ultrasonic detection device according to any one of 5 above.   The parameter changing unit compares the frequency of the transmission signal with the frequency of the reception signal, and when the frequency of the reception signal is higher than the frequency of the transmission signal, lowers the frequency of the transmission signal, The ultrasonic detection device according to claim 1, wherein the frequency of the transmission signal is increased when the frequency of the reception signal is lower than the frequency of the transmission signal.   The ultrasonic sensor includes a first ultrasonic sensor that transmits the transmission signal and a second ultrasonic sensor that is provided separately from the first ultrasonic sensor and that receives the reception signal. The ultrasonic detection device according to any one of claims 1 to 7. The frequency band of the first ultrasonic sensor is wider than the frequency band of the second ultrasonic sensor,
9. The parameter changing unit determines the amount of change in the frequency of the transmission signal so that the second ultrasonic sensor can receive the reception signal near the center frequency. The ultrasonic detection device described. A method of eliminating the influence of ultrasonic waves emitted by other devices by repeatedly applying ultrasonic waves, and detecting an object based on the ultrasonic waves emitted by the own device,
A frequency, a transmission interval, a parameter changing step of changing the type and value of the parameter of the ultrasonic burst wave defined by a plurality of types of parameters including amplitude and burst length,
A transmission step of transmitting the burst wave whose parameters have been changed as a transmission signal,
A reception step of receiving a reflected wave of the transmission signal as a reception signal,
It is determined whether or not the value of the parameter in the received signal changes in the same tendency in association with the change in the value of the parameter, and the received signal in the case of non-interlocking of the transmitted signal of its own device An ultrasonic detection method in which a signal determination step of determining that the reflected wave is not a reflected wave and excluding it is sequentially executed a plurality of times. The computer that controls the device that detects the object based on the ultrasonic waves emitted by itself, eliminating the influence of ultrasonic waves emitted by other devices by repeatedly applying ultrasonic waves,
A frequency, a transmission interval, a parameter changing step of changing the type and value of the parameter of the ultrasonic burst wave defined by a plurality of types of parameters including amplitude and burst length,
A transmission step of transmitting the burst wave whose parameters have been changed as a transmission signal to an ultrasonic sensor,
A reception step of causing the ultrasonic sensor to receive a reflected wave of the transmission signal as a reception signal,
It is determined whether or not the value of the parameter in the received signal changes in the same tendency in association with the change in the value of the parameter, and the received signal in the case of non-interlocking of the transmitted signal of its own device An ultrasonic detection program for sequentially executing a signal determination step of determining that the reflected wave is not a reflected wave and eliminating the signal.

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