JP2019120515A - Radar device, and object detection method of radar device - Google Patents

Abstract

To correctly detect both objects existing far and near.SOLUTION: A radar device has: transmission means (a selection unit 15, and transmission antennas 16-1 and 16-2) that transmits a first pulse signal with prescribed amplitude, and a second pulse signal with amplitude larger than the first pulse signal, respectively; reception means (reception antennas 17-1 to 17-4, and selection unit 18) that receives a reflection signal having the first pulse signal and the second pulse signal reflected by an object; sampling means (an A/D conversion unit 22) that conducts sampling of the reflection signal with respect to the first pulse signal in a first cycle, and conducts sampling of the reflection signal with respect to the second pulse signal in a second cycle longer than the first cycle; and detection means that detects an object present in a prescribed area on the basis of data obtained by being sampled in the first cycle, and detects an object far from the prescribed area on the basis of data obtained by being sampled in the second cycle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a radar device and an object detection method for the radar device.

  In Patent Document 1, an intensity modulation unit is disposed between a voltage control oscillation unit (VCO) and a transmission antenna, a pulse signal is generated by modulating a carrier wave by the intensity modulation unit, and an object is detected by the pulse signal. A technique related to a radar device is disclosed.

JP, 2015-40765, A

  However, in the technique shown in Patent Document 1, when the intensity of the transmission signal is increased to detect an object located far away, the reflected signal from the object located near the radar device saturates and is accurately detected. There is a problem that it can not do.

  An object of the present invention is to provide a radar device and an object detection method of a radar device capable of accurately detecting both a distant object and a nearby object.

In order to solve the above problems, the present invention transmits a first pulse signal having a predetermined amplitude and a second pulse signal having a larger amplitude than the first pulse signal in a radar device for detecting an object. Transmitting means, receiving means for receiving the reflected signal in which the first pulse signal and the second pulse signal are reflected by the object, and sampling the reflected signal for the first pulse signal in a first cycle Sampling means for sampling the reflected signal with respect to the second pulse signal in a second period longer than the first period, and the object in a predetermined region based on data obtained by sampling in the first period The object which is distant from the predetermined area based on data obtained by detecting an object and sampling the second period And having a detecting means for detecting an elephant was the.
According to such a configuration, it is possible to accurately detect both an object located far away and an object located nearby.

Further, the present invention is characterized in that the sampling means performs equivalent time sampling.
According to such a configuration, it is possible to perform sampling at different cycles for the first pulse signal and the second pulse signal, with the sampling cycle of the A / D conversion unit kept constant.

Further, the present invention is characterized in that the number of fields constituting the equivalent time sampling with respect to the first pulse signal is larger than the number of fields constituting the equivalent time sampling with respect to the second pulse signal.
According to such a configuration, it is possible to prevent an unnecessary increase in the amount of data stored in the main area.

Further, according to the present invention, the products of the sampling means, the number of times of performing the equivalent time sampling for the first pulse signal and the second pulse signal, and the number of fields constituting the equivalent time sampling coincide with each other. It is characterized in that it is set to
According to such a configuration, the resolution of the distance is improved instead of narrowing the detection speed range for the first pulse signal, and the detection speed range is widened instead of decreasing the distance resolution for the second pulse signal. Can.

Further, the invention is characterized in that the transmitting means alternately transmits the first pulse signal and the second pulse signal.
According to such a configuration, it is possible to shorten the time for preventing a weak reflection signal.

Further, according to the present invention, determination means for determining whether or not the data obtained by the sampling in the second period is saturated, and data obtained by the sampling in the second period by the determination means Is determined to be saturated, it is characterized by including selection means for selecting the data obtained by the sampling in the first period.
According to such a configuration, the occurrence of false detection can be reduced even when an object having a high reflectance is present in the vicinity.

Further, according to the present invention, in an object detection method of a radar apparatus for detecting an object, a first pulse signal having a predetermined amplitude and a second pulse signal having an amplitude larger than the first pulse signal are respectively transmitted. Transmitting, receiving the first pulse signal and the reflection signal reflected by the second pulse signal, and sampling the reflection signal with respect to the first pulse signal in a first period, Said target object being in a predetermined region based on a sampling step of sampling said reflected signal with respect to said second pulse signal in a second period longer than said first period, and data obtained by sampling in said first period And, based on the data obtained by sampling in the second period, away from the predetermined area A detection step of detecting that the object, characterized by having a.
According to such a method, it is possible to accurately detect both an object located far away and an object located nearby.

  According to the present invention, it is possible to provide a radar device and an object detection method of the radar device capable of accurately detecting both a distant object and a near object.

It is a figure showing an example of composition of a radar installation concerning an embodiment of the present invention. It is a figure which shows an example of the transmission signal of the radar apparatus shown in FIG. It is a figure which shows the detail of equivalent time sampling with respect to main pulse Pm shown in FIG. It is a figure which shows the detail of equivalent time sampling with respect to the subpulse Ps shown in FIG. It is a figure which shows the mode of equivalent time sampling with respect to the transmission signal shown in FIG. It is a flowchart for demonstrating an example of the process performed in embodiment shown in FIG. It is a flowchart for demonstrating the detail of the subpulse reception process shown in FIG. It is a flowchart for demonstrating the detail of the main pulse reception process shown in FIG. It is a flowchart for demonstrating the detail of the process performed in the calculating part shown in FIG. It is a flowchart for demonstrating the detail of the process performed in the calculating part shown in FIG. It is a figure which shows the measurement result of embodiment shown in FIG.

  Next, an embodiment of the present invention will be described.

(A) Description of the Configuration of an Embodiment of the Present Invention FIG. 1 is a view showing an example of the configuration of a radar apparatus according to an embodiment of the present invention. As shown in this figure, the radar device 10 according to the embodiment of the present invention is mounted on a vehicle such as an automobile, for example, and detects an object such as another vehicle, a pedestrian or an obstacle existing around the vehicle Do.

  Here, the radar apparatus 10 includes a control unit 11, an oscillation unit 12, a pulse shaping unit 13, a variable amplification unit 14, a selection unit 15, transmission antennas 16-1 to 16-2, reception antennas 17-1 to 17-4, Main configuration of selection unit 18, amplification unit 19, multiplication unit 20, IF (Intermediate Frequency) amplification unit 21, A / D (Analog to Digital) conversion unit 22, selection unit 23, storage unit 24, and calculation unit 25 It is an element.

  Here, the control unit 11 includes, for example, a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and a field programmable gate array (FPGA), and controls each unit of the apparatus. Do. In addition, the arrow of the broken line in the figure has shown the control line.

  The oscillating unit 12 generates and outputs a local oscillation signal of a predetermined frequency according to the control of the control unit 11.

  The pulse shaping unit 13 shapes and outputs a signal having a pulse waveform corresponding to a sub pulse and a main pulse, which will be described later, based on the control of the control unit 11.

  The variable amplification unit 14 amplifies and outputs the local oscillation signal according to a pulse waveform having a waveform corresponding to the sub pulse and the main pulse supplied from the pulse shaping unit 13. Thereby, the local oscillation signal is shaped so as to have the sub-pulse and the main pulse envelope. The variable amplification unit 14 may be configured by a current control amplification circuit, a voltage control amplification circuit, or the like.

  The selection unit 15 selects any one of the transmission antennas 16-1 to 16-2 according to the control of the control unit 11, and supplies an output signal from the variable amplification unit 14.

  The transmission antennas 16-1 to 16-2 transmit the output signals from the variable amplification unit 14 toward the target as electromagnetic waves.

  The receiving antennas 17-1 to 17-4 receive the reflected signals transmitted by the transmitting antennas 16-1 to 16-2 and reflected by the object, convert the signals into electrical signals (RF (Radio Frequency) signals), and The data is supplied to the selection unit 18.

  The selection unit 18 selects any one of the electrical signals supplied from the reception antennas 17-1 to 17-4 and outputs the selected one to the amplification unit 19.

  The amplification unit 19 amplifies the electric signal output from the selection unit 18 with a predetermined gain and supplies the amplified signal to the multiplication unit 20.

  The multiplication unit 20 multiplies the local oscillation signal supplied from the oscillation unit 12 and the reception signal supplied from the amplification unit 19 to generate and output an IF signal.

  The IF amplifying unit 21 amplifies the IF signal output from the multiplying unit 20 with a predetermined gain and outputs the amplified signal.

  The A / D conversion unit 22 converts the IF signal output from the IF amplification unit 21 into digital data under the control of the control unit 11 and outputs the digital data.

  Under the control of the control unit 11, the selection unit 23 stores the digital data output from the A / D conversion unit 22 in the corresponding storage unit. More specifically, the selection unit 23 stores digital data corresponding to the sub pulse in the sub area 242 and stores digital data corresponding to the main pulse in the main area 241.

  The calculation unit 25 includes detection processing units 251 and 252, a saturation detection unit 253, and an integration processing unit 254.

  The detection processing unit 251 detects an object from digital data corresponding to the main pulse stored in the main area 241 and supplies the target to the saturation detection unit 253.

  The detection processing unit 252 detects an object from digital data corresponding to the sub pulse stored in the sub area 242 and supplies the target to the integration processing unit 254.

  The saturation detection unit 253 detects whether the digital data to be processed by the detection processing unit 251 is not saturated and notifies the detection processing unit 251 of it.

  The integration processing unit 254 executes a process of integrating the data supplied from the detection processing unit 251 and the data supplied from the detection processing unit 252, and the integrated data is, for example, a higher-level device (not shown) (for example, It is supplied to an application processing unit in the radar device 10 or an ECU (Electric Control Unit) outside the radar device 10 or the like.

(B) Description of Operation of Embodiment Next, the operation of the embodiment of the present invention will be described. In the following, the operation of the embodiment of the present invention will be described, and then the detailed operation will be described with reference to the flowcharts of FIGS.

  First, the operation of the present invention will be described with reference to FIGS. When the engine of a vehicle (not shown) equipped with the radar device 10 is started, supply of source power is started to each part of the radar device 10 shown in FIG.

  When the supply of power source power is started, the control unit 11 causes the oscillation unit 12 to start output of the local oscillation signal after a predetermined activation process (for example, device initialization and the like), and the pulse shaping unit A rectangular wave is supplied to 13 to generate a pulse signal. As a result, pulse signals shown in FIG. 2 are output from the transmitting antennas 16-1 to 16-2.

  FIG. 2 is a view showing an example of a transmission signal transmitted from the radar device 10 shown in FIG. As shown in FIG. 2B, the transmission signal includes a sub-pulse Ps having a small amplitude (relatively low power) and a main pulse Pm having a large amplitude (relatively high power).

  The sub pulse Ps is a pulse signal for detecting an object present in a short distance range of, for example, about 0 to 3 m from the radar device 10, and in a range of 0 to 3 m, such as a track, The amplitude As is set so that the received signal does not saturate even when an object having a high electromagnetic wave reflectance is present.

  The main pulse Pm is, for example, a pulse signal for detecting an object present in a range including a long distance of about 70 to 100 m from the radar device 10, including a short distance targeted by the sub pulse Ps described above. If there is an object with a high electromagnetic wave reflectivity, such as a track, etc., at a short distance (for example, in the range of 0 to 3 m), although the received signal is saturated, The amplitude Am is set such that a detectable reflected signal is obtained.

  The period from the sub pulse Ps to the main pulse Pm is T1, and the period from the main pulse Pm to the next sub pulse Ps is T2, as shown in FIG. 2A, a period in which the sub pulse Ps and the main pulse Pm are summed. Is T0, and transmission of the sub-pulses Ps and the main pulse Pm is repeated with a period T0 as a repetition cycle.

  The period T1 is set according to the time from the transmission of the sub-pulses Ps to the arrival of the reflection signal from an object present at a short distance (for example, a range of 0 to 3 m). Further, the period T2 is set according to the time from the transmission of the main pulse Pm to the arrival of the reflection signal from an object present at a long distance (for example, in the range of 70 to 100 m).

  FIG. 2C shows an example of a signal supplied from the pulse shaping unit 13 to the variable amplification unit 14. When the signal supplied from the pulse shaping unit 13 is “H”, the variable amplification unit 14 amplifies and outputs the local oscillation signal supplied from the oscillating unit 12, and the signal supplied from the pulse shaping unit 13 Is not "L", the local oscillation signal supplied from the oscillation unit 12 is not output. As shown in FIG. 2C, the signal supplied from the pulse shaping unit 13 is a pulse so that the amplitude of the pulse signal output from the variable amplification unit 14 becomes As and Am shown in FIG. 2B. Widths Ws and Wm are set.

  In the present embodiment, in the pulse repetition period T0, a transmission signal having a sub-pulse Ps and a main pulse Pm as shown in FIG. 2B is transmitted from one of the transmission antennas 16-1 and 16-2.

  The subpulses Ps transmitted from any one of the transmission antennas 16-1 and 16-2 are reflected by the object and captured as reception signals by the reception antennas 17-1 to 17-4. Similarly, the main pulse Pm transmitted from any one of the transmitting antennas 16-1 and 16-2 is reflected by the object and captured as a reflected signal by the receiving antennas 17-1 to 17-4.

  Since the selection unit 18 selects any one of the reception antennas 17-1 to 17-4, the reflected signal captured by the reception antennas 17-1 to 17-4 selected by the selection unit 18 is an electrical signal. It is converted and supplied to the amplification unit 19.

  Since the subpulse Ps has a small amplitude, the reflected signal is attenuated and hardly captured by the receiving antennas 17-1 to 17-4 when the subpulse Ps is reflected by a distant object. On the other hand, since the main pulse Pm has a larger amplitude than the subpulse Ps, the reflected signal is captured by the receiving antennas 17-1 to 17-4 even when the main pulse Pm is reflected by a distant object. .

  The amplification unit 19 amplifies the electric signal supplied from the selection unit 18 with a predetermined gain and outputs the amplified signal. The multiplication unit 20 performs down conversion by converting the reception signal supplied from the amplification unit 19 by the local oscillation signal supplied from the oscillation unit 12 and converts it into an IF signal and outputs it.

  The IF amplification unit 21 amplifies and outputs the IF signal supplied from the multiplication unit 20. The A / D conversion unit A / D converts and outputs the IF signal supplied from the IF amplification unit 21.

  The selection unit 23 selects and stores the sub region 242 for the data related to the sub pulse Ps in the digital data output from the A / D conversion unit 22. In addition, the selection unit 23 selects and stores the main area 241 for data related to the main pulse Pm among the digital data output from the A / D conversion unit 22.

  The detection processing unit 251 reads the data stored in the main area 241, executes presumming processing, FFT (Fast Fourier Transform) processing, clustering processing, tracking processing, and the like, and detects an object existing around the vehicle. Identify. Similarly, the detection processing unit 252 reads the data stored in the sub area 242, executes presumming processing, FFT processing, clustering processing, tracking processing, and the like, and identifies an object present around the vehicle.

  FIG. 3 is a diagram showing an example of equivalent time sampling processing for the main pulse Pm. FIG. 3A shows the main pulse Pm. Moreover, FIG. 3 (B)-(G) has shown the field in equivalent time sampling. More specifically, when the main pulse Pm shown in FIG. 3A is transmitted, as shown in FIG. 3B, in the first field, the A / D conversion unit starts from the timing when the high frequency pulse signal peaks. 22 performs sampling at a sampling period t1. In the example of FIG. 3, in each field, five samplings are performed as indicated by the arrows. As shown in FIG. 3C, in the second field, sampling is started offset by time τ1 as compared to the first field. The sampling period is t1 as in the first field. As shown in FIG. 3D, in the third field, sampling is started offset by time .tau.1 in comparison with the second field, and similarly, as shown in FIGS. In the third to sixth fields, sampling is started after being offset by time τ1 as compared with the immediately preceding field.

  Although details are not shown in FIG. 3, for example, one high frequency pulse signal is transmitted and received for each of the transmitting antennas 16-1 and 16-2 and the receiving antennas 17-1 to 17-4 in each field. And sampling is performed with the same offset. That is, in the first field, for example, the main pulse Pm is transmitted from the transmission antenna 16-1, and the reflection signal is sampled at each timing shown in FIG. 3B by the reception antenna 17-1. Next, the antenna is switched to the receiving antenna 17-2, and the reflected signal is sampled at each timing shown in FIG. 3 (B). Next, the reflected signals are respectively sampled at the respective timings shown in FIG. 3B by the receiving antennas 17-3 to 17-4. Subsequently, the transmitting antenna 16-2 is switched to the receiving antenna 17-1 to 17-4, and the reflection signal is sampled at each timing shown in FIG. 3B. Assuming that the above operation is one cycle, such a cycle is performed, for example, once for the first field, and data in the first field is acquired. When sampling of the first field is completed, sampling of the second to sixth fields is subsequently performed. When sampling of all fields is completed, the process returns to sampling of the first field again. After repeating such equivalent time sampling processing a predetermined number of times (for example, 2,048 times), processing for detecting an object is executed. Although the number of times of sampling for each field is five in FIG. 3, the number of times for sampling may be other than this (for example, 40 to 50). In each field, one cycle is performed once, but may be repeated other times.

  FIG. 4 is a diagram showing an example of equivalent time sampling processing for the sub pulse Ps. FIG. 4A shows the sub pulse Ps. Moreover, FIG. 4 (B)-(Y) have shown the field in equivalent time sampling. More specifically, when the main pulse Pm shown in FIG. 4A is transmitted, as shown in FIG. 4B, in the first field, the A / D conversion unit starts from the timing when the high frequency pulse signal peaks. 22 performs sampling at a sampling period t1. In the example of FIG. 4, in each field, two samplings are performed as indicated by the arrows. As shown in FIG. 4C, in the second field, sampling is started offset by time τ2 as compared to the first field. Note that τ2 <τ1 and in the present embodiment, τ1 = τ2 × 4 as an example. Of course, other relationships may be set. The sampling period is t1 as in the first field. As shown in FIG. 4 (D), in the third field, sampling is started offset by time .tau.2 compared to the second field, and similarly, as shown in FIGS. 3 (E) to (Y), In the 3 to 24 fields, sampling is started after being offset by time τ 2 as compared with the immediately preceding field.

  Although details are not shown in FIG. 4, for example, one high frequency pulse signal is transmitted and received for each of the transmitting antennas 16-1 and 16-2 and the receiving antennas 17-1 to 17-4 in each field. And sampling is performed with the same offset. That is, in the first field, for example, the sub-pulse Ps is transmitted from the transmission antenna 16-1, and the reflection signal is sampled at each timing shown in FIG. 4B by the reception antenna 17-1. Next, the antenna is switched to the receiving antenna 17-2, and the reflected signal is sampled at each timing shown in FIG. 4 (B). Next, the reflected signals are similarly sampled at the respective timings shown in FIG. 4B by the receiving antennas 17-3 to 17-4. Subsequently, the antenna is switched to the transmitting antenna 16-2, and the reflected signal is sampled at each timing shown in FIG. 4B by the receiving antennas 17-1 to 17-4. Assuming that the above operation is one cycle, such a cycle is performed, for example, once for the first field, and data in the first field is acquired. When sampling of the first field is completed, sampling of the second to sixth fields is subsequently performed. Then, when sampling of all fields is completed, the process returns to the first field again. After repeating such equivalent time sampling processing a predetermined number of times (for example, 512 times), processing for detecting an object is executed. Although the number of times of sampling for each field is two in FIG. 4, the number of times for sampling may be other than this (for example, four to five). In each field, one cycle is performed once, but may be repeated other times.

  FIG. 5 is a schematic diagram showing the equivalent time sampling for the main pulse Pm shown in FIG. 3 and the result of the equivalent time sampling for the sub pulse Ps shown in FIG. 4 together. As shown in FIG. 5, equivalent sampling for the sub-pulse Ps is performed with a time period τ2 as a sampling cycle, and equivalent sampling for the main pulse Pm is performed with a time period τ1 as a sampling cycle. Here, assuming that τ1 = τ2 × 4, the sampling with respect to the sub-pulse Ps is performed at a density four times higher, so the resolution of the distance with respect to the sub-pulse Ps is four times higher than the main pulse Pm. It is.

  In the present embodiment, an object present in the vicinity of the radar device 10 is detected by the sub pulse Ps. The offset interval with respect to the sub-pulse Ps is τ2, and for example, the resolution of the distance is set to be about 15 cm, so it is possible to detect an object present nearby with high resolution. Further, an object present at a long distance from the radar device 10 is detected by the main pulse Pm. The offset interval for the main pulse Pm is τ1 and, for example, the resolution of the distance is set to be about 60 cm, so a distant object can be reliably detected with a smaller data density compared to the subpulse Ps can do. Since the sub-pulse Ps has a small amplitude, it is attenuated before reaching the receiving antennas 17-1 to 17-4 even when it is reflected by a distant object, so in the equivalent time sampling for the main pulse Pm It is sampled and false detection does not occur.

  Data obtained by the above equivalent time sampling is added with a predetermined number of data by presum processing. The data obtained by the presum processing is subjected to FFT processing and converted from the time domain to the frequency domain.

  The detection processing units 251 and 252 execute clustering processing and tracking processing based on the data obtained by the FFT processing to specify an object.

  The saturation detection unit 253 refers to data to be processed by the detection processing unit 251 (for example, data read from the main area 241), and detects the presence or absence of saturation of the reception signal. For example, when part of the data read from the main area 241 is clipped, it can be determined that the data is saturated. The detection processing unit 251 supplies the integration processing unit 254 with the result of the detection processing and the detection result of the presence or absence of saturation.

  The integration processing unit 254 executes processing to integrate data supplied from the detection processing unit 251 and the detection processing unit 252. More specifically, an object detected by the detection processing by the detection processing unit 251 is adopted for a distant object, and an object detected by the detection processing by the detection processing unit 252 is adopted for a nearby object. . In addition, for example, when an object (for example, a track) with a high reflectance is present in a region to be a detection range by the main pulse Pm, a reflected signal from the object may be saturated because the intensity is large. is there. In such a case, since the saturation detection unit 253 detects saturation, the saturated data is not adopted, but the data detected by the sub-pulse Ps is adopted. Even when the reflection signal by the main pulse Pm is saturated, the sub-pulse Ps has a small amplitude, so it is possible to obtain a reflection signal that is not saturated. For this reason, even when an object (for example, a track or the like) having a high reflectance is present nearby, the object can be detected reliably.

  As described above, according to the embodiment of the present invention, the sub pulse Ps and the main pulse Pm are continuously transmitted, and the equivalent time sampling for the sub pulse Ps and the equivalent time sampling for the main pulse Pm are made independent. , And τ1 and τ2 shown in FIGS. 3 and 4 were set such that τ1> τ2. The reflection signal of the subpulse Ps can be sampled with a short period, so that nearby objects can be detected with high resolution. Therefore, when the vehicle is parked, an approaching object can be detected with high resolution, so that contact with the vehicle can be avoided.

  Next, an example of the process performed in the embodiment shown in FIG. 1 will be described with reference to FIGS.

  FIG. 6 is an example of a flowchart for explaining the flow of main processing performed in the embodiment shown in FIG. When the process of the flowchart shown in FIG. 6 is started, the following steps are performed.

  In step S10, the control unit 11 substitutes an initial value 1 into a variable k for counting the number of times of processing.

  In step S11, the control unit 11 substitutes an initial value 1 into a variable j for counting the number of times of processing.

  In step S12, the control unit 11 substitutes an initial value 1 into a variable i for counting the number of times of processing.

  In step S13, the control unit 11 controls the selection unit 15 to select the j-th transmission antenna. The transmission antenna 16-1 and the transmission antenna 16-2 are defined as a first transmission antenna and a second transmission antenna, respectively. Therefore, when j = 1, the transmission antenna 16-1 is selected, and when j = 2, the transmission antenna 16-2 is selected.

  In step S14, the control unit 11 controls the selection unit 18 to select the ith receiving antenna. In addition, each of the receiving antenna 17-1 to the receiving antenna 17-4 is defined as a first receiving antenna to a fourth receiving antenna. Therefore, in the case of i = 1, in the case of i = 2, in the case of i = 2, in the case of i = 3, in the case of i = 4, in the case of i = 4. And the receiving antenna 17-4 is selected.

  In step S15, the control unit 11 transmits the subpulse Ps. More specifically, the control unit 11 controls the oscillation unit 12 to output a local oscillation signal, and supplies the pulse shaping unit 13 with a rectangular wave having a width Ws shown in FIG. 2C. As a result, the local oscillation signal supplied from the oscillation unit 12 is modulated by the signal having the waveform of the sub-pulse Ps supplied from the pulse shaping unit 13 in the variable amplification unit 14, and the amplitude shown in FIG. Sub-pulses Ps are generated. Such subpulses Ps are transmitted from the transmitting antenna selected by the selection unit 15 in step S13.

  In step S16, a sub-pulse reception process is performed. The details of the sub-pulse reception process will be described later with reference to FIG.

  In step S17, the control unit 11 transmits the main pulse Pm. More specifically, the control unit 11 controls the oscillation unit 12 to output a local oscillation signal, and supplies a rectangular wave having a width Wm shown in FIG. 2C to the pulse shaping unit 13. As a result, the local oscillation signal supplied from the oscillation unit 12 is modulated by the signal having the waveform of the main pulse Pm supplied from the pulse shaping unit 13 in the variable amplification unit 14, and the amplitude shown in FIG. A main pulse Pm of Am is generated. Such a main pulse Pm is transmitted from the transmitting antenna selected by the selection unit 15 in step S13.

  In step S18, main pulse reception processing is performed. The details of the main pulse reception process will be described later with reference to FIG.

  In step S19, the control unit 11 increments the variable i for counting the number of times of processing by one.

  In step S20, the control unit 11 determines whether the value of the variable i is larger than 4 and if it is determined to be larger than 4 (step S20: Y), the process proceeds to step S21, otherwise In step S14, the process returns to step S14 to repeat the same process. By repeating the process of step S14 to step S20, the receiving antennas 17-1 to 17-4 are sequentially selected and the receiving process is executed.

  In step S21, the control unit 11 increments the variable j for counting the number of times of processing by one.

  In step S22, the control unit 11 determines whether or not the value of the variable j is larger than 2 and when it is determined that the value is larger than 2 (step S22: Y), the process proceeds to step S23. In step S12, the process returns to step S12 to repeat the same process. By repeating the process of step S12 to step S22, the transmission antennas 16-1 to 16-2 are sequentially selected and the transmission process is executed.

  In step S23, the control unit 11 increments the variable k for counting the number of times of processing by one.

  In step S24, the control unit 11 determines whether or not the value of the variable k is larger than n, and when it is determined that it is larger than n (step S24: Y), the process ends. In step S11, the process returns to step S11 to repeat the same process. By repeating the process of steps S11 to S24, equivalent time sampling shown in FIGS. 3 and 5 is performed. Here, n is the number of repetitions, and is 12,288 in this embodiment. That is, in the main pulse Pm, 2,048 times 6 fields are the number of repetitions, and in the subpulse Ps, 512 times 24 fields are the number of repetitions, and their product is set to 12,288 It is because

  Next, the details of the sub-pulse reception process shown in FIG. 6 will be described with reference to FIG. When the process of the flowchart shown in FIG. 7 is started, the following steps are performed.

  In step S30, the detection processing unit 252 substitutes an initial value 1 into a variable m for counting the number of times of processing.

  In step S31, a reflected signal is received. More specifically, the electromagnetic wave captured by the receiving antenna selected by the selection unit 18 is amplified by the amplification unit 19, multiplied by the local oscillation signal by the multiplication unit 20, and converted into an IF signal, thereby the A / D conversion unit 22 is supplied.

  In step S32, the control unit 11 controls the A / D conversion unit 22 to convert the reflection signal (IF signal) into digital data by A / D conversion. At this time, the control unit 11 controls the offset time τ1.

  In step S33, the control unit 11 controls the selection unit 23, and stores the data output from the A / D conversion unit 22 in the sub area 242 of the storage unit 24.

  In step S34, the control unit 11 increments the variable m for counting the number of times of processing by one.

  In step S35, control unit 11 determines whether or not the value of variable m is larger than 2. If m> 2 is satisfied (step S35: Y), the process proceeds to step S36, otherwise (step S35) In S35: N), the process returns to step S32, and the same process as described above is repeated. Note that, as shown in FIG. 4, two samplings in each field are performed by the processes of step S32 to step S35.

  In step S36, the control unit 11 determines whether the result of (k mod 24) is 0 or not. If 0 (step S36: Y), the process proceeds to step S37, otherwise (step S36: In N), the process proceeds to step S38. Here, mod is an operator for calculating the remainder of dividing k by 24. Here, k is one cycle shown in FIG. 4 (one cycle of transmission processing by both transmission antennas 16-1 to 16-2 and one reception processing by all reception antennas 17-1 to 17-4) is performed. And the value is incremented by one. In the sub-pulse reception process, in one field, one cycle is executed once to advance to the next field, and when the field is advanced to the 24th field, the process returns to the first field to repeat the same process. Therefore, if (k mod 24) becomes 0, the process returns to the first field, otherwise proceeds to the next field.

  In step S37, the control unit 11 shifts to processing of the next field. For example, when the processing of the first field of FIG. 4 is completed at present, the process shifts to the second field.

  In step S38, the control unit 11 returns to the first field. For example, when the processing of the 24th field in FIG. 4 is completed at present, the processing returns to the first field.

  Next, details of the main pulse reception process shown in FIG. 6 will be described with reference to FIG. When the process of the flowchart shown in FIG. 8 is started, the following steps are performed.

  In step S50, the detection processing unit 251 substitutes an initial value 1 into a variable m for counting the number of times of processing.

  In step S51, a reflected signal is received. More specifically, the electromagnetic wave captured by the receiving antenna selected by the selection unit 18 is amplified by the amplification unit 19, multiplied by the local oscillation signal by the multiplication unit 20, and converted into an IF signal, thereby the A / D conversion unit 22 is supplied.

  In step S52, the control unit 11 controls the A / D conversion unit 22 to convert the reflection signal (IF signal) into digital data by A / D conversion. At this time, the control unit 11 controls the offset time τ2.

  In step S53, the control unit 11 controls the selection unit 23, and stores the data output from the A / D conversion unit 22 in the main area 241 of the storage unit 24.

  In step S54, the control unit 11 increments the variable m for counting the number of times of processing by one.

  In step S55, control unit 11 determines whether the value of variable m is larger than 5 or not, and if m> 5 is satisfied (step S55: Y), the process proceeds to step S56, otherwise (step S55) In S55: N), the process returns to step S52, and the same process as described above is repeated. Note that, as shown in each field of FIG. 3, five samplings are performed by the processes of steps S52 to S55.

  In step S56, the control unit 11 determines whether the result of (k mod 6) is 0 or not. If 0 (step S56: Y), the process proceeds to step S57, otherwise (step S56: In N), the process proceeds to step S58. Here, mod is an operator for obtaining the remainder of dividing k by 6 as described above. In the main pulse reception process, in one field, one cycle is executed once to advance to the next field, and when the sixth field is reached, the process returns to the first field to repeat the same process. Therefore, if (k mod 6) becomes 0, the process returns to the first field, otherwise proceeds to the next field.

  In step S57, the control unit 11 returns to the first field. For example, when the processing of the sixth field in FIG. 3 is completed at present, the processing returns to the first field.

  In step S58, the control unit 11 shifts to processing of the next field. For example, when the processing of the first field of FIG. 3 is completed at present, the process shifts to the second field.

  Next, with reference to FIG. 9, a process performed on data for the main pulse Pm in the operation unit 25 shown in FIG. 1 will be described. When the process of the flowchart shown in FIG. 9 is started, the following steps are performed.

  In step S70, the saturation detection unit 253 refers to the data to be processed by the detection processing unit 251 and detects whether part of the data is saturated.

  In step S71, the detection processing unit 251 executes an object detection process. More specifically, the detection processing unit 251 acquires data stored in the main area 241, performs presum processing, FFT processing, clustering processing, tracking processing, and the like, and detects an object. The presum processing need not necessarily be performed.

  In step S72, the integration processing unit 254 acquires the processing result on the sub pulse side from the detection processing unit 252.

  In step S73, the integration processing unit 254 performs integration processing on the processing result on the sub pulse side acquired from the detection processing unit 252 and the processing result on the main pulse side acquired from the saturation detection unit 253. More specifically, the processing result on the main pulse side is adopted for an object present at a distance from the radar device 10, and the processing result on the sub-pulse side is adopted for an object present in the vicinity of the radar device 10. Integrate. In addition, for data whose saturation is detected by the saturation detection unit 253, the processing result on the sub pulse side is adopted.

  In step S74, the integration processing unit 254 outputs the result of the integration processing to a higher-level device (for example, an ECU).

  Next, with reference to FIG. 10, processing to be performed on data for sub-pulse Ps in operation unit 25 shown in FIG. 1 will be described. When the process of the flowchart shown in FIG. 10 is started, the following steps are performed.

  In step S90, the detection processing unit 252 executes an object detection process. More specifically, the detection processing unit 252 acquires data stored in the sub area 242, executes presumming processing, FFT processing, clustering processing, tracking processing and the like, and detects an object. The presum processing need not necessarily be performed.

  In step S91, the detection processing unit 252 supplies the detection result to the integration processing unit 254 as a processing result on the sub pulse side.

  According to the above processing, the above-described operation can be realized.

(C) Description of Modified Embodiments It goes without saying that the above embodiment is an example, and the present invention is not limited only to the case as described above. For example, in the above embodiment, the sub-pulses Ps have 24 fields as shown in FIG. 4, and each field performs sampling twice, and the main pulse Pm is shown in FIG. In addition to the six fields, each field performs sampling five times, but it may have another number of fields and may have another sampling number.

  In the above embodiment, sampling for the sub-pulse Ps and the main pulse Pm is performed at the same sampling cycle t1, but the sampling cycle is changed between the sub-pulse Ps and the main pulse Pm, or sampling cycle is the same. It may be done.

  In the above embodiment, although the pulse repetition period T0 shown in FIG. 2 is fixed, in order to prevent a pulse signal of the previous cycle from being received in the next pulse cycle and occurrence of false detection, For example, false detection may be prevented by changing T0.

  Further, in the above embodiment, as the integration process, although adopting one of the data is described as an example, in addition to this, for example, an object detected by the main pulse Pm, and a sub-pulse The same target object may be specified with the target object detected by Ps, and when the target object moves from a distance to a nearby position, a handover process may be performed between them.

  Further, although the sub-pulses Ps and the main pulse Pm are alternately transmitted in the above embodiment, they may be transmitted by other methods.

  Further, in the above embodiment, although the four-wheeled vehicle was described as an example of the vehicle, a motorcycle, a bicycle or the like may be detected other than this. That is, in the present specification, a vehicle is not limited to a four-wheeled vehicle.

  Further, it is needless to say that the processes of the flowcharts shown in FIGS. 6 to 10 are one example, and the present invention is not limited to the processes of these flowcharts.

  In addition, it may be determined whether or not saturation occurs based on whether the intensity of the reflected signal of the main pulse Pm is equal to or higher than a predetermined power intensity.

Reference Signs List 10 radar device 11 control unit 12 oscillation unit 13 pulse shaping unit 14 variable amplification unit 15 selection unit 16-1 to 16-2 transmission antenna 17-1 to 17-2 reception antenna 18 selection unit 19 amplification unit 20 multiplication unit 21 IF amplification Unit 22 A / D conversion unit 23 Selection unit 24 Storage unit 25 Operation unit 241 Main area 242 Sub-region 251 Detection processing unit 252 Detection processing unit 253 Saturation detection unit 254 Integration processing unit

Claims (7)

In a radar device for detecting an object,
Transmitting means for transmitting a first pulse signal having a predetermined amplitude and a second pulse signal having a larger amplitude than the first pulse signal;
Receiving means for receiving a reflected signal in which the first pulse signal and the second pulse signal are reflected by the object;
Sampling means for sampling the reflection signal for the first pulse signal at a first period, and sampling the reflection signal for the second pulse signal at a second period longer than the first period;
While detecting the said target object in a predetermined area | region based on the data obtained by sampling in the said 1st period, it is distant from the said predetermined area | region based on the data obtained by sampling in the said 2nd period Detection means for detecting a certain target object;
The radar apparatus characterized by having.   The radar apparatus according to claim 1, wherein the sampling means performs equivalent time sampling.   The radar apparatus according to claim 2, wherein the number of fields constituting the equivalent time sampling for the first pulse signal is larger than the number of fields constituting the equivalent time sampling for the second pulse signal.   The sampling means is set such that the product of the number of times of performing the equivalent time sampling on the first pulse signal and the second pulse signal and the number of fields constituting the equivalent time sampling is equal to each other The radar apparatus according to claim 2 or 3, wherein   The radar apparatus according to any one of claims 1 to 4, wherein the transmitting means transmits the first pulse signal and the second pulse signal alternately. A determination unit that determines whether the data obtained by the sampling in the second period is saturated or not;
Selecting means for selecting the data obtained by the sampling in the first cycle when it is judged by the judging means that the data obtained by the sampling in the second cycle is saturated;
The radar apparatus according to any one of claims 1 to 5, comprising: In an object detection method of a radar device for detecting an object,
A transmitting step of transmitting a first pulse signal having a predetermined amplitude and a second pulse signal having a larger amplitude than the first pulse signal;
Receiving the first pulse signal and the reflected signal that the second pulse signal is reflected by the object;
Sampling the reflected signal with respect to the first pulse signal at a first period, and sampling the reflected signal with respect to the second pulse signal at a second period longer than the first period;
While detecting the said target object in a predetermined area | region based on the data obtained by sampling in the said 1st period, it is distant from the said predetermined area | region based on the data obtained by sampling in the said 2nd period Detecting a certain target object;
A method of detecting an object of a radar device, comprising:

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