JP5055207B2 - Velocity measuring device and displacement measuring device - Google Patents

Description

  The present invention relates to a speed measurement device that measures the speed of a reception point using positioning data based on radio waves received from a positioning satellite. The present invention also relates to a displacement measuring device that measures the displacement of a receiving point.

Conventionally, speed measurement using a carrier phase of a positioning satellite such as GPS (Global Positioning System) has been performed. For example, Patent Document 1 describes that the speed of a reception point is measured using a Doppler frequency shift amount that is a speed component of a carrier phase.
JP 2006-105635 A

  In conventional speed measurement, an external device acquires various data such as a carrier wave phase obtained by a receiver through communication, and the external device calculates a speed. In such a configuration, in order to reduce communication costs or increase the number of samples that can be communicated at a limited communication speed to improve accuracy, the data size of the carrier phase per sample must be reduced. There is a time.

  When the carrier phase data observed at the receiver has a data size limited to the lower digits excluding the upper digits, range restriction occurs in the range of velocity component data calculated from the carrier phase data. To do. In this state, if the satellite direction component of the speed of the reception point exceeds the value range, the speed of the reception point cannot be obtained.

For example, for the L1 carrier phase (frequency: 1575.42 MHz / wavelength: about 19 cm) of GPS satellites observed at 40 msec intervals, if the observed data is only fractional part data with the integer part omitted, the satellite and receiving point The measurement range of the change amount of the L1 carrier phase (Doppler frequency shift) due to the relative speed is 0.0 [km / h] to approximately 17.1 [km / h] (see the following formula (1)) when expressed in positive numbers. Become.
0.19 [m] /0.04 [sec] = 4.75 [m / s] = 17.1 [km / h] (1)

  Therefore, even if the speed of the reception point is reflected in the “speed component data of the carrier wave phase”, the speed component data has a range restriction of about 17.1 [km / h]. Therefore, when measuring in a moving body such as a passenger car, speed measurement in a practical range (0 to 180 km / h, etc.) becomes difficult.

  The present invention has been made in view of the above-described problems. Even when data having a limit in the range is used, by using the concept of indeterminacy based on a newly defined indeterminate value, the speed of the reception point is obtained. It is an object of the present invention to provide a speed measuring device capable of obtaining the displacement and a displacement measuring device capable of obtaining the displacement of the reception point.

  The present invention has been made to solve the above-described problem, and receives the radio wave from the positioning satellite and acquires the positioning data based on the radio wave, and the positioning data including the carrier phase data. A first velocity component calculation unit that calculates a velocity component of the carrier phase based on the carrier phase, and an indefinite value calculation that calculates an indefinite value of the velocity component of the carrier phase according to a data size or a time interval related to the data of the carrier phase A second velocity component calculation unit that calculates the velocity component of the carrier phase that has resolved indefiniteness by adding the indefinite value to the velocity component of the carrier phase, and the second velocity component calculation unit. A speed measurement apparatus comprising: a reception point speed calculation unit that calculates a speed of a reception point based on the calculated velocity component of the carrier phase and a direction cosine.

  In the velocity measuring device according to the present invention, the indefinite value calculating unit calculates the indefinite value based on a velocity component of the carrier phase and an approximate velocity of a reception point.

  Further, the present invention calculates a Doppler frequency shift based on a receiving unit that receives radio waves from a positioning satellite and acquires positioning data based on the radio waves, and the positioning data including Doppler frequency data. A first Doppler frequency deviation calculating unit; an indeterminate value calculating unit for calculating an indeterminate value of the Doppler frequency deviation according to a data size related to the Doppler frequency data; and adding the indeterminate value to the Doppler frequency deviation. By doing so, the second Doppler frequency shift calculation unit for calculating the Doppler frequency shift in which the indefiniteness is eliminated, the Doppler frequency shift and the direction cosine calculated by the second Doppler frequency shift calculation unit A speed measurement device comprising a reception point speed calculation unit that calculates a speed of a reception point based on the reception point.

  In the speed measurement device of the present invention, the indeterminate value calculating unit calculates the indeterminate value based on the Doppler frequency shift and the approximate speed of the reception point.

  Further, the present invention calculates a velocity component of a carrier phase based on the receiving unit that receives radio waves from a positioning satellite and acquires positioning data based on the radio waves, and the positioning data including carrier phase data. A first velocity component calculating unit that calculates an indefinite value of a single difference between satellites in the velocity component of the carrier phase according to a data size or a time interval related to the carrier phase data, and the carrier A second velocity component calculating unit that calculates the inter-satellite single difference of the velocity component of the carrier phase in which the indeterminacy is eliminated by adding the indefinite value to the inter-satellite single difference of the phase velocity component; And a reception point velocity calculation unit for calculating the velocity of the reception point based on a single-satellite single difference between the velocity components of the carrier phase calculated by the velocity component calculation unit and a direction cosine. With speed measuring device That.

  In the speed measurement device of the present invention, the indeterminate value calculating unit calculates the indeterminate value based on a single difference between satellites in a velocity component of the carrier phase and an approximate speed of a reception point. .

  Further, the present invention calculates a Doppler frequency shift based on a receiving unit that receives radio waves from a positioning satellite and acquires positioning data based on the radio waves, and the positioning data including Doppler frequency data. A first Doppler frequency deviation calculating unit; an indeterminate value calculating unit for calculating an indefinite value of a single difference between satellites of the Doppler frequency deviation according to a data size related to the Doppler frequency data; and the Doppler frequency deviation. A second Doppler frequency shift calculation unit for calculating a single difference between the satellites of the Doppler frequency shift in which the indefiniteness is eliminated by adding the indefinite value to the single difference between the satellites of the second satellite, and the second Doppler A receiving point speed calculating unit that calculates the speed of the receiving point based on the inter-satellite single difference and the direction cosine of the Doppler frequency shift calculated by the frequency shift calculating unit; A velocity measuring device, characterized in that the.

  In the speed measurement device of the present invention, the indeterminate value calculating unit calculates the indeterminate value based on a single difference between satellites in the Doppler frequency shift and an approximate speed of a reception point.

  In addition, the present invention includes the above-described speed measurement device, and a reception point displacement calculation unit that calculates the displacement of the reception point by integrating the speeds of the reception points calculated by the reception point speed calculation unit. It is a displacement measuring device.

  According to the speed measurement device of the present invention, the speed of the reception point can be obtained by using the concept of indefiniteness based on a newly defined indeterminate value even when data having a limit in the range is used. The effect that it can be obtained. In addition, according to the displacement measuring apparatus of the present invention, the displacement of the reception point is obtained by using the concept of indeterminacy based on a newly defined indeterminate value even when data having a limit in the range is used. The effect that it can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the technical idea of the present invention applied to this embodiment will be described. As described above, when the carrier phase data observed by the receiver has a data size limited to the lower digits excluding the upper digits, the range of velocity component data calculated from the carrier phase data is A range limitation occurs. In this state, if the satellite direction component of the speed of the reception point exceeds the value range, the speed of the reception point cannot be obtained.

  Here, the inventors pay attention to the characteristic that the range of the velocity component data of the carrier phase is limited according to the “data size” and the “use data time interval” (for example, the observation time interval) of the carrier phase, We have invented a method and apparatus for obtaining the value of the original velocity component (the value when there is no limit in the range) using the “limit of the range” having this characteristic. The method using this characteristic is a speed limited by intentionally setting the data size and the data interval used based on the above characteristics according to the speed range, required accuracy, frequency, and communication speed of the measurement target. Use the component value range size (hereinafter referred to as the speed component data unit), or use the speed component value range limited in advance in the existing device configuration, and use the constant value as an integer. By calculating the double offset amount for each satellite and adding it to the original data value of each satellite (the data value of the velocity component whose range is limited), the value of the original velocity component for all observed satellites And a speed of the reception point is calculated.

  However, in the process of the present invention, since the integer value for calculating the offset amount is unknown, it is necessary to separately obtain the integer value. Here, the unknown integer value is defined as “unknown integer value”, and the value of the offset amount of the uncertain speed component is defined as “undefined value of the speed component”. When this definition is applied to the corresponding part of the present invention, “a solution of an unknown integer value (integer solution) is obtained for each satellite, and the product of“ data unit of velocity component ”and the calculated“ solution of unknown integer value ”. The specific solution of “obtaining the original value by adding the solution of the indefinite value of the velocity component” to the original data value of each satellite can be derived.

In the present invention in which the concept of indefiniteness as described above is newly introduced, the definition formula for the velocity component of the carrier phase is shown below. First, when “amount corresponding to the data size of the carrier phase” is S and “use data time interval” is Δt, the data unit Uv of the velocity component of the carrier phase can be defined by the following equation (2). .
Uv = S / Δt (2)

  Hereinafter, it will be described that the “data unit Uv of the velocity component” defined by the equation (2) matches the measurement range in which the range is limited. For example, as in the case described above, for the L1 carrier phase (frequency: 1575.42 MHz / wavelength: about 19 cm) of the GPS satellite observed at 40 msec intervals, the observed data is only the fractional part with the integer part omitted. In this case, the measurement range of the change amount (observation amount) of the L1 carrier phase due to the relative velocity between the satellite and the receiving point is expressed as a positive number from 0.0 [km / h] to about 17.1 [km / h] (described above (1) (See formula). Also, due to normalization at half wavelength, the observed value range is ± 8.56 [km / h].

  Therefore, even if the speed of the reception point is reflected in the observation amount, since the integer part of the carrier phase data is omitted, the observation amount is about 17.1 [based on one wavelength of the L1 frequency that is a unit of the data size. km / h] exists. Here, based on the newly introduced concept of indefiniteness, this “measurement range based on the observed amount limitation” is regarded as “a data unit with the limited range as one unit” and the defined equation (2) is applied. To do. At this time, S in the formula (2) is about 0.19 [m], Δt is 0.04 [sec], Uv is 17.1 [km / h], and the “velocity component data unit Uv” according to this definition matches the measurement range. .

  For the GPS satellite L1 carrier phase (frequency: 1575.42 MHz / wavelength: about 19 cm) observed at 40 msec intervals, the observed data is only the fractional part with the integer part omitted, and the usage data time interval is 200 msec. When set to, the measurement range of the change amount (observation amount) of the L1 carrier phase due to the relative velocity between the satellite and the receiving point is expressed as a positive number from 0.0 [km / h] to about 3.42 [km / h] (the following (See equation (3)). Also, due to normalization at half wavelength, the observed value range is ± 1.71 [km / h].

Therefore, even if the speed of the receiving point is reflected in the observation amount, there is a limit of about 3.42 [km / h] in the observation amount. Here, this “measurement range based on the observed amount limit” is defined as “a data unit with the limit range as one unit” based on the newly introduced concept of indeterminacy, as in the previous example. Apply equation (2). At this time, S in the formula (2) is about 0.19 [m], Δt is 0.2 [sec], Uv is 3.42 [km / h], and the “velocity component data unit Uv” according to this definition matches the measurement range. .
0.19 [m] /0.2 [sec] = 0.95 [m / s] = 3.42 [km / h] (3)

Furthermore, the “carrier phase velocity component” obtained by adding indefinite values can be defined by the following equation (4). Here, an "indefinite value of the speed component" of (Uv · ^N i v) is the satellite i.
^{Φ i vu = Φ i v +} (Uv · N i v) ··· (4)
Φ ⁱ vu: Velocity component of carrier phase of satellite i (addition of indefinite value)
Φ ⁱ v: velocity component of carrier phase of satellite i (value range is the range of data unit)
Uv: Data unit of velocity component N ⁱ v: Unknown integer value of satellite i

  As a supplementary explanation, “integer value indefiniteness” (also referred to as integer value ambiguity, etc.), which is generally considered in relative positioning based on the GPS carrier phase, is a characteristic on the system that indicates the observed phase in the positioning. This indicates that the integer wave number is indeterminate. Therefore, the unit of indefiniteness is fixed at 1 [cycle]. Further, it is unrelated to the “use data time interval” of the carrier phase data. That is, the “data value indefiniteness” in the present invention based on an arbitrary data unit based on the “data size” and the “use data time interval” of the carrier phase is the above-mentioned general “integer value indefiniteness” It is a different concept.

  Next, using the concept of indefiniteness of data values based on “data size” and “usage data time interval”, a method for obtaining the speed of a reception point using data on the velocity component of the carrier phase having a limit in the range Will be explained. FIG. 1 shows the configuration of a velocity and displacement measuring apparatus according to this embodiment. In FIG. 1, an antenna 1 receives radio waves from positioning satellites 4a to 4d such as GPS.

  The positioning processing unit 2 is provided in the receiver main body and includes a satellite receiving unit 2a and a positioning unit 2b. The satellite receiver 2a processes an electrical signal based on the radio wave received by the antenna 1, outputs the positioning data to the positioning unit 2b, and also uses the carrier phase (or Doppler frequency) that is the positioning data and the navigation message. Data is output to the data processing unit 3. The positioning unit 2b calculates the approximate position and time of the reception point based on the positioning data from the satellite receiving unit 2a, and outputs the calculation result data and the receiver clock bias to the data processing unit 3. The approximate position of the reception point is obtained using the code phase.

  The data processing unit 3 is provided in a device outside the receiver, and calculates the speed and displacement of the reception point based on various data input from the positioning processing unit 2. Although FIG. 1 shows the positioning satellites 4a to 4d, the number of positioning satellites is not limited as long as the number is three or more.

  Hereinafter, the calculation method of the reception point velocity and the reception point displacement will be described along the procedure shown in FIG. The data processing unit 3 includes a volatile or non-volatile memory that can read and write data, stores various data received from the satellite receiver 2a and the positioning unit 2b in the memory, and stores the various data in the memory. Read from the memory as appropriate and execute the following calculation. In addition, the data processing unit 3 stores the calculation result in each step in the memory, and in subsequent steps, appropriately reads the calculation result in the previous step from the memory and executes the calculation.

(Step S100)
First, the data processing unit 3 receives the data of the approximate position / time of the receiving point and the receiver clock bias from the positioning unit 2b.

(Step S110)
Subsequent to step S100, the data processor 3 receives the carrier phase (or Doppler frequency) and navigation message data from the satellite receiver 2a, and executes the following processing. First, the data processing unit 3 calculates the approximate speed of the reception point and the approximate clock drift of the receiver. The approximate speed of the reception point is obtained from the amount of change per unit time of the approximate position of the reception point (latitude, longitude, altitude three components, or three components x, y, and z of the coordinate system fixed to the earth). In addition, when the low pass filter process is performed on the approximate position of the reception point calculated by the positioning unit 2b, it is desirable to match the filter time constant with the filter time constant of the carrier phase. Further, the approximate speed of the reception point may be obtained from the output value of an external sensor (vehicle speed pulse, tide meter, magnetic azimuth sensor, inclinometer, etc.). The approximate clock drift of the receiver is determined from the rate of change of the receiver clock bias. In this embodiment, it is assumed that the approximate speed of the reception point is calculated outside the GPS receiver. However, as another form, the approximate speed of the reception point may be calculated inside the GPS receiver. Good.

(Step S120)
Subsequent to step S110, the data processing unit 3 verifies the calculation result of the approximate speed of the reception point. By this test, the calculation result of the approximate speed is determined as OK or NG. In the following cases, it is impossible or invalid to calculate the approximate speed of the reception point, and it is determined that the calculation result is NG. The first case is a case where the approximate speed cannot be obtained without calculating the approximate position of the reception point at the observation timing of the carrier phase due to the low frequency of measurement of the approximate position of the reception point. The second case is a case where an abnormality occurs in the approximate position of the reception point, and the reliability of the approximate speed is reduced and becomes invalid.

  The reliability of the approximate speed can be determined by comparing the difference between the change amount of the approximate speed and the integrated value of the reception point acceleration separately calculated at the same time with a predetermined reference value. A method of calculating the reception point acceleration will be described later. If it is determined in step S120 that the calculation result is OK, the process proceeds to step S140. If it is determined that the calculation result is NG, the process proceeds to step S130.

(Step S130)
When it is determined in step S120 that the calculation result is NG, the data processing unit 3 adds the integrated value of the reception point acceleration calculated separately to the effective reception point approximate speed calculated in the past. Then, an estimated value of the approximate reception point speed is calculated. Thereafter, the process proceeds to step S140.

(Step S140)
The data processing unit 3 calculates the velocity component (observation amount) of the carrier phase. As shown in the following equations (5) and (6), the data processing unit 3 calculates a velocity component of the carrier phase by taking a time difference with respect to the carrier phase acquired at the observation time.
Φ ⁱ v (t _k ) = (Φ ⁱ (t _k ) −Φ ⁱ (t _k−1 )) / Δt (5)
Δt = t _k −t _k−1 (k = 1, 2, 3,...) (6)
Φ ⁱ (t _k ): carrier phase of satellite i observed at time t _k Φ ⁱ v (t _k ): velocity component of carrier phase of satellite i at time t _k t _k : observation time of carrier phase Δt: observation time interval

In the above, although the latest time t _k of the velocity component of the carrier phase [Phi ^{i v} (t _k) observation time the time that defines the (from time t _k-1 to time t _k), the observation time intermediate time It is good also as tm (refer the following (7) Formula). In this case, the following equation (8) is used instead of the above equation (5). In all cases where velocity components such as error components and reception point velocity components are calculated, the velocity component is calculated according to this definition.
tm = (t _k + t _k−2 ) / 2 (7)
Φ ⁱ v (tm) = (Φ ⁱ (t _k ) −Φ ⁱ (t _k−1 )) / Δt (8)
Φ ⁱ v (tm): velocity component of carrier phase of satellite i at time tm

(Step S150)
Subsequent to step S140, the data processing unit 3 calculates the satellite position when the observed carrier phase is launched, using the propagation time of the carrier wave and the satellite orbit information obtained from the navigation message. Based on the satellite position and the approximate position of the reception point, the data processing unit 3 calculates the velocity component of the distance between the satellite and the receiver as indicated by the following expressions (9) to (14). Similarly to the case of calculating the velocity component of the carrier phase, the data processing unit 3 calculates the velocity component of the satellite-receiver distance by taking the time difference with respect to the satellite-receiver distance. In addition, the two observation times of the satellite-receiver distance used for calculating the time difference are the same as the time used for calculating the observation amount. Further, the approximate position Q of the reception points used when calculating the velocity component of the satellite-receiver distance is the same position at two time sets (t _k , t _k-1 ). The propagation time of the carrier wave can be calculated from the optical path difference equation.
D ⁱ v (t _k ) = (D ⁱ (t _k ) −D ⁱ (t _k−1 )) / Δt (9)
D ⁱ (t _k ) = | P ′ ⁱ (t _k ) −Q | (10)
D ⁱ (t _k−1 ) = | P ′ ⁱ (t _k−1 ) −Q | (11)
P ′ ⁱ (t _k ) = P ⁱ (t _k −τ ⁱ (t _k )) (12)
P ′ ⁱ (t _k−1 ) = P ⁱ (t _k−1 −τ ⁱ (t _k−1 )) (13)
Δt = t _k −t _k−1 (k = 1, 2, 3,...) (14)
D ⁱ v (t _k ): velocity component of the distance between the satellite and the receiver due to the movement of the satellite i at the time t _k D ⁱ (t _k ): the distance between the satellite i and the approximate position of the reception point at the time t _k P ′ ⁱ (t _k ): satellite position P ⁱ (t _k ) when the carrier phase of satellite i observed at time t _k is launched from satellite i: position τ ⁱ (t _k ) of satellite i at time t _k : The propagation time of the carrier wave of satellite i observed at time t _k Q: the approximate position of the receiving point t _k : the observation time of the carrier phase Δt: the observation time interval

  Further, the data processing unit 3 calculates a satellite clock error, an ionospheric delay amount in each satellite direction, and a tropospheric delay amount in each satellite direction. The satellite clock error and the ionospheric delay amount in each satellite direction can be calculated by the method described in the GPS interface specification ICD-GPS-200. Further, the estimated value of the tropospheric delay amount in each satellite direction can be calculated by various model equations. The satellite position, satellite clock error, ionospheric delay amount in each satellite direction, and tropospheric delay amount in each satellite direction may be corrected using the SBAS information.

  Further, the data processing unit 3 takes the time difference at the generation time of each data corresponding to the time of the observation amount for the satellite clock error, the ionospheric delay amount in each satellite direction, and the tropospheric delay amount in each satellite direction, The velocity component of the satellite clock error, the velocity component of the ionospheric delay amount in each satellite direction, and the velocity component of the tropospheric delay amount in each satellite direction are calculated. The speed component of the satellite-receiver distance, the speed component of the satellite clock error, the speed component of the ionospheric delay in each satellite direction, and the speed component of the tropospheric delay in each satellite direction are error components. And

(Step S160)
Subsequent to step S150, the data processing unit 3 removes the velocity component (error component) other than the reception point calculated in step S150 from the velocity component (observation amount) of the carrier phase calculated in step S140, and Normalized to the range of data units, the reception point velocity component of the carrier phase is calculated. Further, the approximate clock drift of the receiver calculated here in step S110 may be removed. Moreover, you may remove the influence by the relativistic effect and the motion of the earth.

(Step S170)
Subsequent to step S160, the data processing unit 3 calculates an indefinite value of the reception point velocity component of the carrier phase. Hereinafter, the method for calculating the indefinite value will be described with reference to FIG. First, the data processing unit 3, a schematic velocity vector _{V O} of the receiving points based on the estimated value of the outline speed or schematic speed reception points calculated in step S110 and S130, each satellite i (i = 1, 2, 3, ...) To obtain the vector V _O ⁱ (satellite direction component of the approximate velocity at the reception point).

Subsequently, the data processing unit 3 uses the data component of the velocity component and the unknown integer value for the reception point velocity component Φ ⁱ vr of the carrier phase calculated in step S160 (the data value of the velocity component with a limited range). The reception point speed of the carrier wave phase is obtained by adding a value (candidate value of an indefinite value of the speed component) multiplied by the candidate value (..., -2, -1, 0, 1, 2,. Component candidate values 300 and 300a are calculated. The data processing unit 3 selects the candidate value 300a (reception point velocity vector V) that is closest to the value of the vector V _O ⁱ from among the candidate values 300 and 300a of the reception point velocity component of the carrier phase calculated as described above. ₍ corresponding to a vector value obtained by projecting _r in the direction of satellite i). The indeterminate value candidate value used when calculating the candidate value is the indefinite value solution.

(Step S180)
Subsequent to step S170, the data processing unit 3 adds the solution of the indeterminate value calculated in step S170 to the reception point velocity component of the carrier phase, thereby calculating the reception point velocity component of the carrier phase in which the indefiniteness is eliminated. .

(Step S190)
Subsequent to step S180 or step S210 described later, the data processing unit 3 calculates a direction cosine from the approximate position of the reception point and the satellite position. Subsequently, the data processing unit 3 receives the carrier phase reception point velocity component, direction cosine and unknown number (four unknowns of the three-dimensional velocity of the reception point and the receiver clock drift) for which the indefiniteness has been resolved for four or more satellites. The speed of the reception point is calculated by an equation (the following equation (15)).
Rv = H · Xv (15)
Rv: reception point velocity component matrix of carrier phase with indeterminateness H: direction cosine matrix Xv: reception point velocity and receiver clock drift (4 unknowns)

  When the number of satellites is 3, the smoothed latest receiver clock drift rate is added to the latest receiver clock drift obtained in the past, and an estimated value of the receiver clock drift is calculated. By using the estimated value of the receiver clock drift and solving an equation in which the three reception point velocity components are unknown, the reception point velocity can be obtained even with three satellites. When the number of satellites is four or more, the indeterminate value in step S170 is determined by using the value obtained by removing the estimated value of the receiver clock drift for the reception point velocity component of the carrier phase of each satellite. It is possible to improve the reliability of the solution.

(Step S200)
Subsequent to step S190, the data processing unit 3 determines the reliability (OK / NG) of the reception point speed calculated in step S190 by using one or more of the following three methods.
(A) Indeterminate that the index value due to the residual of the receiving point velocity component of the carrier phase based on each indeterminate value is minimum in the vicinity of the indeterminate value solution obtained for each satellite (for example, the solution of unknown integer value ± 1). A combination of values is obtained, and when the combination matches the first obtained solution combination, it is determined as OK.
(B) In the vicinity of an indeterminate value solution obtained for each satellite, a first candidate for a combination of indeterminate values that minimizes an index value due to the residual of the receiving point velocity component of the carrier phase based on each indeterminate value, and the index value Is determined to be the second smallest candidate, and when the combination of the first candidates matches the first combination of solutions of indeterminate values, the ratio between the index values of the first candidate and the second candidate is set to a predetermined reference value. To determine reliability.
(C) The difference between the change amount of the receiving point velocity component of the carrier phase based on the solution of the indeterminate value obtained for each satellite and the integrated value of the receiving point acceleration component of the carrier phase calculated separately at the same time is a predetermined reference value Reliability is determined by comparing with.

  If it is determined in step S200 that the reliability of the reception point speed is OK, that is, the reception point speed is reliable, the process proceeds to step S220, and the reliability of the reception point speed is NG, that is, the reception point speed is unreliable. If it is determined, the process proceeds to step S210.

(Step S210)
In step S200, when it is determined that the reliability of the reception point speed is NG, the data processing unit 3 uses all the satellites used in the calculation of the reception point speed or the satellite that is determined to be NG. The estimated value of the receiving point velocity component of the carrier phase is calculated by adding the integrated value of the receiving point acceleration component of the carrier phase calculated separately to the receiving point velocity component of the effective carrier phase calculated in the past. To do. Thereafter, the process returns to step S190.

(Step S220)
Subsequent to step S210, the data processing unit 3 calculates the displacement of the reception point by integrating the reception point speed according to the following equation (16).

(Step S230)
Subsequent to step S220, the data processing unit 3 applies a low-pass filter to the reception point velocity and reception point displacement calculated as described above to remove noise components. By repeating the processes of steps S100 to S230, the data processing unit 3 calculates the reception point velocity and the reception point displacement. Note that the process of step S230 may be omitted as appropriate.

Next, a method for calculating the reception point acceleration component will be described. As shown in the following equation (17), the data processing unit 3 calculates the acceleration component (observation amount) of the carrier phase by taking a double time difference for the carrier phase acquired at the observation time. Further, as shown in the following equation (18), it is assumed that the time intervals of the three observation times (t _k , t _k−1 , t _k−2 ) of the carrier phase used for calculating the time difference are equal.
Φ ⁱ a (t _k ) = {(Φ ⁱ (t _k ) −Φ ⁱ (t _k−1 )) − (Φ ⁱ (t _k−1 ) −Φ ⁱ (t _k−2 ))} / Δt ² ... (17)
Δt = t _k −t _k−1 = t _k−1 −t _k−2 (k = 2, 3, 4,...) (18)
Φ ⁱ (t _k ): carrier phase of satellite i observed at time t _k Φ ⁱ a (t _k ): acceleration component of carrier phase of satellite i at time t _k t _k : observation time of carrier phase Δt: observation time interval

In the above, the time at which the acceleration component Φ ⁱ a (t _k ) of the carrier phase is defined is the latest time t _k of the observation time (from time t _k−2 to time t _k ). It is good also as tm (refer the following (19) Formula). In this case, the following equation (20) is used instead of the above equation (17). Further, in all cases where acceleration components such as an error component and a reception point acceleration component are calculated, the acceleration component is calculated according to this definition.
tm = (t _k + t _k−2 ) / 2 (19)
Φ ⁱ a (tm) = {(Φ ⁱ (t _k ) −Φ ⁱ (t _k−1 )) − (Φ ⁱ (t _k−1 ) −Φ ⁱ (t _k−2 ))} / Δt ^2. (20)
Φ ⁱ a (tm): acceleration component of the carrier phase of satellite i at time tm

Subsequently, based on the satellite position when the observed carrier phase is launched and the approximate position of the reception point, the data processing unit 3 determines the satellite as shown in the following expressions (21) to (27). -Calculate the acceleration component of the distance between the receivers. As in the case of calculating the acceleration component of the carrier phase, the data processing unit 3 calculates the acceleration component of the satellite-receiver distance by taking a double time difference for the satellite-receiver distance. In addition, the three observation times of the satellite-receiver distance used for calculating the time difference are the same as the time used in the calculation of the observation amount, and the three observation times are as shown in the following equation (28). The time intervals shall be equal. Furthermore, the approximate position Q of the reception point used when calculating the acceleration component of the satellite-receiver distance is the same position at the three sets of time (t _k , t _k−1 , t _k−2 ). And The propagation time of the carrier wave can be calculated from the optical path difference equation.
^{_{D i a (t k) =}} {(D i (t k) -D i (t k-1)) - (D i (t k-1) -D i (t k-2))} / Δt 2 ... (21)
D ⁱ (t _k ) = | P ′ ⁱ (t _k ) −Q | (22)
D ⁱ (t _k−1 ) = | P ′ ⁱ (t _k−1 ) −Q | (23)
D ⁱ (t _k−2 ) = | P ′ ⁱ (t _k−2 ) −Q | (24)
P ′ ⁱ (t _k ) = P ⁱ (t _k −τ ⁱ (t _k )) (25)
P ′ ⁱ (t _k−1 ) = P ⁱ (t _k−1 −τ ⁱ (t _k−1 )) (26)
P ′ ⁱ (t _k−2 ) = P ⁱ (t _k−2− τ ⁱ (t _k−2 )) (27)
Δt = t _k −t _k−1 = t _k−1 −t _k−2 (k = 2, 3, 4,...) (28)
D ⁱ a (t _k ): acceleration component of the distance between the satellite and the receiver due to the movement of the satellite i at the time t _k D ⁱ (t _k ): the distance P ′ between the satellite i and the approximate position of the reception point at the time t _k ⁱ (t _k ): satellite position P ⁱ (t _k ) when the carrier phase of satellite i observed at time t _k is launched from satellite i: position τ ⁱ (t _k ) of satellite i at time t _k : The propagation time of the carrier wave of satellite i observed at time t _k Q: the approximate position of the receiving point t _k : the observation time of the carrier phase Δt: the observation time interval

  Further, the data processing unit 3 calculates a satellite clock error, an ionospheric delay amount in each satellite direction, and a tropospheric delay amount in each satellite direction. The satellite clock error and the ionospheric delay amount in each satellite direction can be calculated by the method described in the GPS interface specification ICD-GPS-200. Further, the estimated value of the tropospheric delay amount in each satellite direction can be calculated by various model equations. The satellite position, satellite clock error, ionospheric delay amount in each satellite direction, and tropospheric delay amount in each satellite direction may be corrected using the SBAS information.

  Further, the data processing unit 3 takes a double time difference at the generation time of each data corresponding to the time of the observation amount for the satellite clock error, the ionospheric delay amount in each satellite direction, and the tropospheric delay amount in each satellite direction. Thus, the acceleration component of the satellite clock error, the acceleration component of the ionospheric delay amount in each satellite direction, and the acceleration component of the tropospheric delay amount in each satellite direction are calculated. These acceleration components other than the receiving point are the acceleration component of the satellite-receiver distance, the acceleration component of the satellite clock error, the acceleration component of the ionospheric delay in each satellite direction, and the acceleration component of the tropospheric delay in each satellite direction. And

  Subsequently, the data processing unit 3 removes the acceleration component (error component) other than the reception point calculated as described above from the acceleration component (observed amount) of the carrier phase, and normalizes the acceleration component in the data unit range. And the reception point acceleration component of the carrier wave phase is calculated.

Subsequently, the data processing unit 3 calculates a direction cosine from the approximate position of the reception point and the satellite position. Further, the data processing unit 3 is configured to receive the reception point acceleration component of the carrier phase, the direction cosine, and the unknown number (four unknowns of the three-dimensional acceleration of the reception point and the receiver clock drift rate) from which error components are removed for four or more satellites. The acceleration at the reception point is calculated using an equation (the following equation (29)).
Ra = H · Xa (29)
Ra: receiving point acceleration component matrix of carrier phase H: direction cosine matrix Xa: receiving point acceleration and receiver clock drift rate (4 unknowns)

  By calculating the reception point acceleration in parallel with the calculation of the reception point velocity and reception point displacement described above, it is possible to calculate the reception point velocity, reception point acceleration, and reception point displacement at each observation time. is there. In the acceleration measurement, the range of the value is limited as in the velocity measurement. Therefore, by setting the data size and the use data time interval to appropriate sizes in advance, it is possible to avoid the occurrence of an unmeasurable range based on the range limit for the acceleration range to be measured. However, in practice, in acceleration measurement, an unmeasurable range based on the range limit is less likely to occur than in speed measurement.

For example, as in the case described above, for the L1 carrier phase (frequency: 1575.42 MHz / wavelength: about 19 cm) of the GPS satellite observed at 40 msec intervals, the observed data is only the fractional part with the integer part omitted. In this case, the unit of the limit range of the acceleration range is about 118.9 [m / s ² ] (about 12.1G) (see the following equation (30)). In this case, in the practical range (0 to 3G, etc.), the limitation of the range is not a problem.
0.19 [m] /0.04 [sec] /0.04 [sec] = 118.9 [m / s ² ] (about 12.1G) (1G = 9.80665 [m / s ² ]) (30)

  Next, a modification of this embodiment will be described. The data unit of the velocity component of the carrier phase in the above is described as a predetermined constant value for all observed satellites, but a different constant value may be set individually for each satellite.

Alternatively, the reception point velocity may be calculated using a single difference between satellites in the reception point velocity component of the carrier wave phase described below. The single-satellite single difference of receiving point velocity components is a difference between receiving point velocity components of different satellites that are independent from each other. For example, the receiving point velocity components of satellites i and j can be expressed as in the following equations (31) and (32) in consideration of indefinite values. However, the condition is that the data units Uv of the satellites i and j are equal.
^{Φ i vru = Φ i vr +} (Uv · N i v) ··· (31)
Φ ^j vru = Φ ^j vr + (Uv · N ^j v) (32)
Φ ⁱ vru: satellite i reception point velocity component (value added with indefinite value)
Φ ^j vru: the receiving point velocity component of satellite j (value added with indefinite value)
Φ ⁱ vr: component of receiving speed of satellite i (value normalized in data units)
Φ ^j vr: satellite j reception point velocity component (value normalized in data units)
N ⁱ v: Unknown integer value of velocity component of satellite i N ^j v: Unknown integer value of velocity component of satellite j Uv: Data unit of velocity component

By taking the difference between equation (31) and equation (32), the single-satellite single difference of the reception point velocity component is expressed by equation (33) below.
^{Φ j vru-Φ i vru =} (Φ j vr-Φ i vr) + (Uv · (N j v-N i v)) ··· (33)

When the difference portion in the equation (33) is replaced with a variable having a single difference, the following equation (34) is obtained.
ΔΦ ^ji vru = ΔΦ ^ji vr + (Uv · ΔN ^ji v) (34)
ΔΦ ^ji vru: Single difference between satellites in the velocity component of the reception point between satellite i and satellite j (value added with indefinite value)
ΔΦ ^ji vr: Single difference between satellites in the velocity component of the reception point by satellite i and satellite j (value normalized by data unit)
ΔN ^ji v: Single difference between satellites of unknown integer value based on data unit of satellite i and satellite j Uv: Data unit of velocity component

  As shown in the above equation (34), when the data unit of the velocity component of one set (two) of satellites has the same size, the single difference between the satellites of the reception point velocity component is based on the data unit. It can be considered to have indefiniteness. If this characteristic is used, an indefinite value solution is calculated after canceling common components (receiver clock drift, etc.) caused by the inside of the receiver due to the single difference between satellites in the “received point velocity component of the carrier phase”. The reception point speed can be obtained.

  Details will be described below. First, the reception point velocity component of the carrier phase from which the error component is removed from the observation amount is obtained, and the single unit difference between three or more sets of satellites in which the data units of each set of velocity components are equal and independent from each other is calculated. This "single-satellite single difference of receiving point velocity component" has indefiniteness based on the data unit as described above.

Subsequently, vectors V _O ⁱ and V _O ^j (reception) are obtained by projecting the approximate velocity vector V _O of the reception point in the direction of the satellite (for example, i and j) used in the “single difference between the satellites of the reception point velocity component”. The satellite direction component of the approximate point velocity is obtained, and the single-satellite single difference V _O ^ji (substantially single difference) is calculated. Then, a candidate value closest to the “substantially single difference ΔV _O ^ji ” is selected from candidate values of “single difference between satellites of receiving point velocity component” having indefiniteness, and this candidate value is calculated. The “undefined value of the single difference between satellites” used sometimes is obtained as a solution.

Furthermore, solve 3 or more independent equations by "single difference between satellites of reception point velocity component of carrier phase", direction cosine, and unknown number (three-dimensional component of reception point velocity) that solved indefiniteness. Thus, the reception point speed is obtained. For example, an equation using a single difference between satellites by a mutually independent combination, such as the following formulas (35) to (37), may be solved.
ΔΦ ²¹ vrun = Δh ²¹ · Vr (35)
ΔΦ ³¹ vrun = Δh ³¹ · Vr (36)
ΔΦ ⁴¹ vrun = Δh ⁴¹ · Vr (37)
ΔΦ ^ji vrun: “Single difference between satellites in the velocity component of the receiving phase of the carrier phase” that solved the indefiniteness of satellite i and satellite j
Δh ^ji : Single difference between satellites in direction cosine by satellite i and satellite j Vr: Speed of reception point (3 unknowns)

  Next, a modified example of this embodiment in the indefinite value solution will be described. In the indefinite value solution method, in this embodiment, the candidate value closest to the vector value obtained by projecting the approximate velocity vector in the direction of each satellite is selected from the candidate values of the reception point velocity component for each satellite. However, as a modification, an index for directly searching for the reception point velocity vector may be newly defined, and the solution of the reception point velocity may be determined based on the index value.

  First, with respect to the vector value obtained by projecting the approximate velocity vector in the direction of each satellite, a plurality of reception point velocity vector candidates (referred to as candidate vectors) based on indefinite value candidates limited to the periphery thereof are calculated. Here, an index indicating the degree of similarity between the candidate vector and the approximate speed vector is newly defined. Then, a candidate vector determined to have the highest similarity according to the index value may be used as a solution. As an index of similarity, for example, when the magnitude of the difference between a three-dimensional candidate vector and an approximate speed vector is defined as an index, the candidate vector when the index value is the minimum is the solution of the reception point speed.

  In addition, when calculating a candidate vector in this modification, the above-described “single difference between speed components between satellites” may be used. In other words, based on the vector value obtained by projecting the approximate velocity vector in the direction of each satellite, a single difference between satellites by a combination of each satellite is obtained, and based on “candidates for indefinite values of single difference between satellites” limited to the periphery Thus, it is possible to calculate a plurality of candidate vectors using the above-described single difference equation between satellites.

  In addition, by using the concept of unknown integer value based on the data unit defined in the present invention and the approximate velocity vector, it is possible to use various integer solution search methods used in relative positioning based on the existing GPS carrier phase. it can. For example, a real value of an unknown integer value based on the data unit corresponding to a vector value obtained by projecting the approximate velocity vector in the direction of each satellite or a single difference between the satellites is calculated. Then, an integer solution of an unknown integer value is obtained by obtaining an integer solution (generally called a float solution and a fix solution) from the real number solution using an index (generally called a cost function) in an existing integer solution search method. The solution of the receiving point speed can be obtained by fixing.

  In addition, as a method of calculating the indefinite value of the reception point velocity component of the carrier phase, the observation is performed with five or more satellites, and for all combinations of indeterminate values satisfying the required measurement range, the sum of squares of the respective satellite residuals. (Or an index value based on the residual) is calculated, and a combination of indefinite values that minimizes the value may be used as the solution. However, in this method, five or more satellites are required, and the number of combinations of indefinite values increases exponentially as the number of satellites increases, and a solution is obtained in real time as the CPU processing load increases. It becomes difficult.

  In this embodiment, the “component due to satellite movement”, which is one of the error components in the velocity component and acceleration component of the carrier phase, will be described using the velocity component and acceleration component of the satellite-receiver distance. However, the direction cosine component of the velocity and acceleration of the satellite calculated based on the satellite position in the earth fixed coordinate system may be used as the “component due to the movement of the satellite”.

  In the above description, the velocity component and acceleration component of the carrier phase are used as the observation amount. Instead, the Doppler frequency shift (corresponding to the velocity component of the carrier phase) and the amount of change (speed component of the Doppler frequency shift) are used instead. May be used as an observable. When Doppler frequency data that is a speed component is used, it is not necessary to take a time difference, so the data unit of the speed component depends only on the data size.

  Further, in the calculation of the reception point acceleration, the indefiniteness of the data value may be solved as in the case of the calculation of the reception point velocity.

  As described above, according to the present embodiment, the concept of indeterminacy based on a newly defined indeterminate value is used even when data of a velocity component (or Doppler frequency) of a carrier phase having a limit in the range is used. By using this, the reception point velocity and the reception point displacement can be obtained. Therefore, the data size can be reduced, and when the reception point speed or the like is calculated by an external device of the receiver, data acquired at a higher sampling frequency can be transmitted from the receiver to the external device. As a result, the followability of measurement is improved as compared with the prior art, and the accuracy is improved because the number of data increases. Alternatively, when data having the same frequency as the conventional one is transmitted, the communication cost can be reduced by reducing the data size.

  In addition, measurement can be performed with high accuracy by using the carrier wave phase. Furthermore, since the receiving point velocity can be obtained by observing the carrier phase at two consecutive times, the measurement can be performed in a short observation time. Furthermore, a low-cost measurement system can be configured without requiring a reference receiver.

  In addition, by calculating the reception point velocity from which an error component such as receiver clock drift is removed, it is possible to calculate a highly accurate reception point displacement by integrating the reception point velocities.

  In addition, by calculating the reception point velocity using the single-point difference between the satellites of the reception point velocity component, the reception point velocity is calculated after canceling the common component caused by the inside of the receiver. The speed can be calculated. In addition, the reliability of the indefinite value solution obtained in the process is improved.

  As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the above-described embodiments, and includes design changes and the like without departing from the gist of the present invention. . For example, in the present embodiment, the data processing unit 3 is described as being provided in a device outside the receiver. However, the data processing unit 3 is provided in the receiver together with the satellite receiving unit 2a and the positioning unit 2b. It may be.

It is a block diagram which shows the structure of the speed and displacement measuring device by one Embodiment of this invention. It is a flowchart which shows the procedure in which the velocity and displacement measuring device by one Embodiment of this invention calculates a receiving point speed and receiving point displacement. In one Embodiment of this invention, it is explanatory drawing for demonstrating the calculation method of an indefinite value.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Antenna, 2 ... Positioning processing part, 2a ... Satellite receiving part, 2b ... Positioning part, 3 ... Data processing part, 4a, 4b, 4c, 4d ... Satellite for positioning

Claims (9)

A receiving unit that receives radio waves from a positioning satellite and acquires positioning data based on the radio waves;
A first velocity component calculator that calculates a velocity component of the carrier phase based on the positioning data including the carrier phase data;
An indeterminate value calculating unit that calculates an indeterminate value of the velocity component of the carrier phase according to a data size or a time interval related to the data of the carrier phase;
A second velocity component calculator that calculates the velocity component of the carrier phase that has been resolved by adding the indefinite value to the velocity component of the carrier phase;
A receiving point speed calculating unit that calculates a speed of a receiving point based on the speed component of the carrier phase and the direction cosine calculated by the second speed component calculating unit;
A speed measuring device comprising:   The speed measurement apparatus according to claim 1, wherein the indeterminate value calculation unit calculates the indeterminate value based on a speed component of the carrier phase and an approximate speed of a reception point. A receiving unit that receives radio waves from a positioning satellite and acquires positioning data based on the radio waves;
A first Doppler frequency shift calculation unit that calculates a Doppler frequency shift based on the positioning data including Doppler frequency data;
An indeterminate value calculating unit that calculates an indeterminate value of the Doppler frequency shift according to a data size related to the data of the Doppler frequency;
A second Doppler frequency shift calculator that calculates a Doppler frequency shift that has solved the indeterminacy by adding the indefinite value to the Doppler frequency shift;
A reception point speed calculation unit that calculates a speed of the reception point based on the Doppler frequency shift and the direction cosine calculated by the second Doppler frequency shift calculation unit;
A speed measuring device comprising:   The speed measurement device according to claim 3, wherein the indeterminate value calculation unit calculates the indeterminate value based on the Doppler frequency shift and the approximate speed of a reception point. A receiving unit that receives radio waves from a positioning satellite and acquires positioning data based on the radio waves;
A first velocity component calculator that calculates a velocity component of the carrier phase based on the positioning data including the carrier phase data;
An indeterminate value calculating unit that calculates an indeterminate value of a single difference between satellites of a velocity component of the carrier phase according to a data size or a time interval related to the data of the carrier phase;
A second velocity component calculator that calculates the inter-satellite single difference of the velocity component of the carrier phase with the indeterminacy eliminated by adding the indefinite value to the inter-satellite single difference of the velocity component of the carrier phase;
A receiving point speed calculating unit that calculates the speed of the receiving point based on the single-satellite single difference and the direction cosine of the speed component of the carrier phase calculated by the second speed component calculating unit;
A speed measuring device comprising:   6. The speed measurement apparatus according to claim 5, wherein the indeterminate value calculation unit calculates the indeterminate value based on a single difference between satellites in a velocity component of the carrier phase and an approximate speed of a reception point. A receiving unit that receives radio waves from a positioning satellite and acquires positioning data based on the radio waves;
A first Doppler frequency shift calculation unit that calculates a Doppler frequency shift based on the positioning data including Doppler frequency data;
An indeterminate value calculating unit that calculates an indeterminate value of a single difference between satellites of the Doppler frequency shift according to a data size related to the data of the Doppler frequency;
A second Doppler frequency shift calculating unit that calculates the inter-satellite single difference of the Doppler frequency shift by eliminating the indeterminacy by adding the indefinite value to the inter-satellite single difference of the Doppler frequency shift;
A reception point speed calculation unit that calculates a speed of a reception point based on a single difference between satellites of the Doppler frequency shift calculated by the second Doppler frequency shift calculation unit and a direction cosine;
A speed measuring device comprising:   The speed measurement device according to claim 7, wherein the indeterminate value calculation unit calculates the indeterminate value based on a single difference between satellites in the Doppler frequency shift and an approximate speed of a reception point. The speed measuring device according to any one of claims 1 to 8,
A receiving point displacement calculating unit that integrates the speeds of the receiving points calculated by the receiving point speed calculating unit and calculates a displacement of the receiving point;
A displacement measuring apparatus comprising:

Images