JP7111298B2 - Satellite selection device and program - Google Patents

Description

The present invention relates to a satellite selection device and program.

Conventionally, when receiving signals from multiple satellites and calculating one's own position, among the signals from multiple satellites, some of the satellite signals are not used to calculate the position of one's own position. A device is known (Patent Document 1). In this position detection device, the difference between the Doppler frequency generated by the relative velocity between the receiver that receives the signal from the satellite and the satellite, the difference between the measured value measured while the receiver is stationary and the predicted value is greater than the threshold It calculates its own position without using signals from

Also, there is known a navigation satellite receiver that calculates the distance from a satellite to a receiver and calculates the position of the receiver without using the distances calculated for some satellites (Patent Document 2). . In this navigation satellite receiver, the estimated distance from the satellite to the receiver is used as an approximate distance, and the distance from the satellite to the receiver is calculated based on the time difference between the time when the signal was sent from the satellite and the time when the signal was received by the receiver. The resulting distance is obtained as a pseudo distance. The position of the receiver is calculated without using the approximate and pseudoranges for satellites whose difference between these pseudoranges and approximate ranges (hereinafter referred to as pseudorange residuals) exceeds a threshold.

JP-A-11-118903 JP-A-2003-57327

However, when receiving signals from a plurality of satellites and calculating its own position, it is affected by multipaths in which signals reflected from buildings and the like and direct signals from the satellites coexist. In Patent Document 1, when the difference between the measured value and the predicted value of the Doppler frequency is equal to or greater than a threshold, it is determined that the signal is affected by multipath, and the signal from the satellite is not used. Calculate the position of At this time, a method of setting a threshold according to the speed of the moving object has been proposed. However, since the speed of the mobile object is irrelevant to whether or not there is a multipath environment, it is difficult for this method to set an appropriate threshold that takes into account the Doppler frequency prediction error due to the influence of multipath. For example, if the threshold is too large, satellites with large multipath errors cannot be excluded, and if the threshold is too small, satellites not affected by multipath may be excluded.

Moreover, the above-mentioned Patent Document 2 describes that the position of the receiver is calculated in consideration of the influence of multipath. However, when there is a large error in the obtained pseudorange residual, it is difficult to determine whether or not the error is affected by multipath, so it is difficult to set an appropriate threshold.

Here, the pseudorange includes a distance error caused by an estimation error of the receiver position and an estimation error of the receiver time shift. In order to suppress the estimation error of the receiver time lag, instead of using the pseudorange residual as it is, the pseudorange residual of the satellite with the highest elevation angle is used as the reference value, and the reference value of the pseudorange residual and each satellite Based on the difference from the pseudorange residual (difference of pseudorange residual), it is conceivable to discriminate a satellite with a large pseudorange error affected by multipath. Since the receiver time lag error is common to each satellite, the influence of the receiver time lag error can be excluded.

On the other hand, the estimation error of the receiver position does not have the same effect on the calculation accuracy of the pseudorange residual for each satellite. For example, if a position error occurs in the direction of approaching the satellite with the highest elevation angle, the pseudorange residual with the highest elevation satellite will be small, while the pseudorange residual with other satellites can be large. have a nature. Therefore, it is difficult to reduce the influence of position estimation accuracy.

The present invention has been made in consideration of the above facts, and provides a satellite selection device and program capable of selecting satellites capable of accurate calculation when obtaining at least one of the position and velocity of a mobile object on the earth. intended to

In order to achieve the above object, a first aspect of the present disclosure is a positioning device that calculates the position on the earth of a location to be positioned on a mobile body that is different from installation locations of a plurality of satellite antennas installed on the mobile body. A satellite selection device for selecting a satellite to be used, comprising information on the position of each of the plurality of satellites transmitted from each of the plurality of satellites and information on the distance between each of the plurality of satellites and the mobile object a satellite information acquisition unit that acquires satellite information including information; and information on the plurality of satellites observed at each installation location of the plurality of satellite antennas based on the satellite information acquired by the satellite information acquisition unit. an observation pseudo-range deriving unit that derives observation pseudo-range information indicating a distance between each of the plurality of satellite antennas and each of the plurality of satellite antennas; each of the plurality of satellites and each of the plurality of satellite antennas according to each position from the position to be measured calculated based on the positional relationship obtained by the satellite information acquisition unit and the satellite information acquired by the satellite information acquisition unit; an estimated pseudorange calculation unit for estimating estimated pseudorange information indicating the distance between the a residual derivation unit for deriving a residual between the observed pseudorange information and the estimated pseudorange information estimated by the estimated pseudorange calculation unit; and each of the plurality of satellite antennas derived by the residual derivation unit. a satellite selection unit that selects a satellite to be excluded from the satellites to be used based on the residual difference of the satellite selection device.

A second aspect of the present disclosure is the satellite selection device according to the first aspect, wherein the satellite selection unit excludes satellites corresponding to residual differences equal to or greater than a predetermined threshold from the satellites to be used.

A third aspect of the present disclosure, in the satellite selection device of the first aspect or the second aspect, further includes a reliability determination unit that determines the reliability of each time error of each receiver of the plurality of satellite antennas, The satellite selection unit selects a satellite to be excluded from the satellites to be used based on the residual difference of each of the plurality of satellite antennas only when the reliability determination unit determines that the reliability is high. do.

A fourth aspect of the present disclosure is the satellite selection device according to the third aspect, wherein the reliability determination unit determines which of the residuals derived by the residual derivation unit for a predetermined number of different satellites. or when the residual of one satellite antenna is within a threshold with respect to the residual of the other satellite antennas, it is determined that the reliability of the time error of the receiver is high.

A fifth aspect of the present disclosure is a satellite that selects a satellite to be used in a speed measuring device that calculates the speed on the earth of a positioning target location on a mobile object that is different from installation locations of a plurality of satellite antennas installed on the mobile object. A selection device for selecting satellite information including information on the position of each of the plurality of satellites transmitted from each of the plurality of satellites and information on the relative velocity between each of the plurality of satellites and the mobile body a satellite information acquisition unit that acquires; each of the plurality of satellites and the plurality of satellites observed at installation locations of each of the plurality of satellite antennas based on the satellite information acquired by the satellite information acquisition unit; an observed Doppler frequency derivation unit for deriving observed Doppler frequency information indicating relative velocities with respect to each of the satellite antennas; a velocity relationship between the installation location of each of the plurality of satellite antennas and the positioning target location; and the satellite information an estimated Doppler frequency calculator for estimating estimated Doppler frequency information indicating relative velocities between each of the plurality of satellites and each of the plurality of satellite antennas based on the satellite information obtained by the obtaining unit; , the observed Doppler frequency information derived by the observed Doppler frequency derivation unit and the estimated Doppler frequency estimated by the estimated Doppler frequency calculation unit for each of the plurality of satellite antennas for each of the plurality of satellites a residual derivation unit for deriving a residual with respect to frequency information; and a satellite selection unit for selecting a satellite to be used from the satellites.

A sixth aspect of the present disclosure is the satellite selection device according to the fifth aspect, wherein the satellite selection unit excludes satellites corresponding to residual differences equal to or greater than a predetermined threshold from the satellites to be used.

A seventh aspect of the present disclosure is the satellite selection device of the fifth aspect or the sixth aspect, comprising The satellite selection unit further includes, only when the reliability determination unit determines that the reliability is high, based on the residual difference of each of the plurality of satellite antennas, the satellite selection unit excludes from the satellites to be used Choose a satellite.

An eighth aspect of the present disclosure is the satellite selection device according to the seventh aspect, wherein the reliability determination unit selects the plurality of residuals derived by the residual derivation unit for a predetermined number of different satellites. If the residual error of any one of the satellite antennas is within a threshold with respect to the residual errors of the other satellite antennas, it is determined that the reliability of the amount of change in the time error of the receiver is high.

A ninth aspect of the present disclosure is for selecting a satellite to be used in a positioning device that calculates the position on the earth of a positioning target location on a mobile object that is different from installation locations of a plurality of satellite antennas installed on the mobile object. satellite information including information on the position of each of the plurality of satellites transmitted from each of the plurality of satellites and information on the distance between each of the plurality of satellites and the mobile body each of the plurality of satellites and the plurality of satellites observed at installation locations of each of the plurality of satellite antennas based on the satellite information acquired by the satellite information acquisition section; an observation pseudo-range derivation unit for deriving observation pseudo-range information indicating a distance to each of the satellite antennas; a predetermined positional relationship between each installation location of the plurality of satellite antennas and the positioning target location; estimating a distance between each of the plurality of satellites and each of the plurality of satellite antennas according to each position from the location to be measured calculated based on the satellite information acquired by the information acquisition unit; an estimated pseudorange calculation unit for estimating pseudorange information; for each of the plurality of satellites, for each satellite antenna of the plurality of satellite antennas, the observed pseudorange information derived by the observed pseudorange derivation unit; a residual derivation unit for deriving a residual from the estimated pseudorange information estimated by the pseudorange calculation unit; and a difference in the residual of each of the plurality of satellite antennas derived by the residual derivation unit. Based on this, the program functions as a satellite selection unit that selects satellites to be excluded from the satellites to be used.

A tenth aspect of the present disclosure is for selecting a satellite to be used in a speed measuring device that calculates the speed on the earth of a positioning target location on a mobile object that is different from installation locations of a plurality of satellite antennas installed on the mobile object. comprising information on the position of each of the plurality of satellites transmitted from each of the plurality of satellites and information on the relative velocity between each of the plurality of satellites and the mobile body a satellite information acquisition unit that acquires satellite information; each of the plurality of satellites observed at each of the plurality of satellite antennas based on the satellite information acquired by the satellite information acquisition unit; Observation Doppler frequency deriving unit for deriving observation Doppler frequency information indicating relative velocity between each of the plurality of satellite antennas, velocity relationship between installation location of each of the plurality of satellite antennas and the positioning target location, and the satellite an estimated Doppler frequency calculator for estimating estimated Doppler frequency information indicating relative velocities between each of the plurality of satellites and each of the plurality of satellite antennas based on the satellite information obtained by the information obtaining unit; , the observed Doppler frequency information derived by the observed Doppler frequency derivation unit and the estimated Doppler frequency estimated by the estimated Doppler frequency calculation unit for each of the plurality of satellite antennas for each of the plurality of satellites a residual derivation unit for deriving a residual from frequency information; This is a program for functioning as a satellite selection unit that selects a satellite to be used from among the satellites of the

Note that the storage medium that stores the program of the present disclosure is not particularly limited, and may be a hard disk or a ROM. Also, it may be a CD-ROM, a DVD disk, a magneto-optical disk, or an IC card. Furthermore, the program may be downloaded from a server or the like connected to a network.

Advantageous Effects of Invention According to the present disclosure, it is possible to obtain the effect of being able to select a satellite capable of accurate calculation when obtaining at least one of the position and velocity of a mobile object on the earth.

1 is a block diagram showing a positioning device according to a first embodiment; FIG. FIG. 4 is a diagram showing an example in which two GPS antennas are installed with the vehicle center as the location to be measured. FIG. 5 is a diagram showing an example of a vehicle attitude angle calculation result at a certain time; FIG. 4 is a diagram for explaining a positional relationship calculation method between a positioning target location and an antenna installation location in the ENU coordinate system; 4 is a flow chart showing the content of a positioning processing routine in a computer of the positioning device according to the first embodiment; FIG. 3 is a block diagram showing a positioning device according to a second embodiment; FIG. 9 is a flow chart showing the contents of a positioning processing routine in a computer of the positioning device according to the second embodiment; FIG. 11 is a block diagram showing a velocity measuring device according to a third embodiment; FIG. FIG. 5 is a diagram showing an example of the angular velocity and attitude angle calculation results of a vehicle at a certain time; FIG. 4 is a diagram for explaining a speed relationship calculation method between a positioning target location and an antenna installation location in the ENU coordinate system; 14 is a flow chart showing contents of a speed measurement processing routine in a computer of the speed measurement device according to the third embodiment; FIG. 11 is a block diagram showing a velocity measuring device according to a fourth embodiment; FIG.

Hereinafter, embodiments for implementing the technology of the present disclosure will be described in detail with reference to the drawings. In the present embodiment, a case where the technology of the present disclosure is applied to a positioning device that is mounted on a vehicle and performs positioning by acquiring GPS information transmitted from GPS satellites will be described as an example.

<Overview of this embodiment>
When positioning is performed using multiple GNSS antennas, the positioning target location and the GNSS antenna installation location where observation values are obtained do not match. Positions and velocities calculated with satellite information from the affected satellites are less accurate than those not affected by multipath errors.

In this embodiment, by appropriately considering the positional relationship and speed relationship between the positioning target location and each GNSS antenna installation location, and excluding satellites affected by multipath errors in advance, Using only the satellite information, it is possible to calculate the position and velocity of the location to be positioned with high accuracy.

<First Embodiment>
FIG. 1 shows an example of the configuration of the positioning device according to the first embodiment.
As shown in FIG. 1, a positioning device 10 according to the first embodiment includes a plurality of GPS antennas 12A and 12B for receiving radio waves from GPS satellites, and a plurality of GPS antennas 12A and 12B for receiving radio waves from GPS satellites. A plurality of receivers 14A and 14B that acquire received signals, an attitude angle sensor 16, the received signals from the GPS satellites received by the plurality of receivers 14A and 14B, and the detection values of the attitude angle sensor 16, It comprises a satellite selection device 18 that selects a GPS satellite to be used, and a position derivation unit 40 that executes positioning processing for estimating the position of the own vehicle. The satellite selection device 18 includes a computer 30 that executes satellite selection processing for selecting GPS satellites to be used for deriving the position of a positioning target location, and an output unit 20 .

FIG. 2 shows an example of installation locations of the plurality of GPS antennas 12A and 12B.
For example, as shown in FIG. 2, the plurality of GPS antennas 12A and 12B are installed in the interior of the vehicle 50, and are installed at locations different from the locations targeted for positioning. In this embodiment, an example is considered in which the location to be measured is the center of the vehicle, and two GPS antennas 12A and 12B and receivers 14A and 14B are installed at the positions shown in FIG. Here, it is assumed that the distances of the respective GPS antennas 12A and 12B from the location to be positioned (vehicle center) can be accurately grasped by manual measurement.

The receivers 14A and 14B are provided for each of the GPS antennas 12A and 12B. The receivers 14A and 14B receive radio waves from a plurality of GPS satellites via the GPS antennas 12A and 12B and GPS satellite information such as GPS satellite number, GPS satellite orbital information (ephemeris), time when GPS satellite transmitted radio waves, strength of received signal, frequency, etc. 30.
The attitude angle sensor 16 is, for example, a geomagnetic sensor and detects geomagnetism.

The computer 30 in the satellite selection device 18 is composed of a CPU, a ROM storing a program for realizing processing described later, a RAM temporarily storing data, and a storage device such as an HDD.

If the computer 30 is represented by functional blocks, as shown in FIG. A satellite discriminator 37 is provided. The satellite information acquisition unit 31 according to the first embodiment is an example of the satellite information acquisition unit and the observation pseudorange derivation unit of the present disclosure. The estimated pseudorange calculation unit 34 is an example of the estimated pseudorange derivation unit of the present disclosure. The pseudorange residual calculation unit 35 is an example of the residual derivation unit of the present disclosure. The excluded satellite determination unit 37 is an example of the satellite selection unit of the present disclosure.

The satellite information acquisition unit 31 acquires GPS satellite information for all GPS satellites that have received radio waves, and calculates and acquires GPS pseudorange data, Doppler frequencies, and GPS satellite position coordinates. Specifically, the satellite information acquisition unit 31 acquires GPS satellite information from each of the receivers 14A and 14B for all GPS satellites that have received radio waves, and also obtains the time when the GPS satellites transmitted radio waves and the vehicle. GPS pseudo-range data is calculated based on the time when the radio waves are received at . Further, the satellite information acquisition unit 31 determines the Doppler frequency of the signal received from each GPS satellite based on the known frequency of the signal transmitted from each GPS satellite and the frequency of the received signal received from each GPS satellite. calculate. The Doppler frequency is obtained by observing the Doppler shift amount of the carrier frequency due to the relative velocity between the GPS satellite and the own vehicle. The satellite information acquisition unit 31 also calculates the position coordinates of the GPS satellites based on the orbital information of the GPS satellites and the time when the GPS satellites transmitted radio waves.

The antenna position/receiver time error calculation unit 32 calculates the positional relationship between the location on the earth where each of the GPS antennas 12A and 12B is installed and the location to be positioned, which is calculated based on the attitude angle of the own vehicle, and the acquired satellite information. Based on the positions of the positioning target points determined using the GPS antennas 12A and 12B, the positions of the GPS antennas 12A and 12B and the time errors of the receivers 14A and 14B are calculated.

Specifically, the antenna position/receiver time error calculator 32 calculates the attitude angle of the host vehicle from the detection value of the attitude angle sensor 16 as a first step. In this embodiment, the attitude angle of the own vehicle at the time is calculated by using the detection value of the attitude angle sensor 16 as the attitude angle of the own vehicle. In the present embodiment, a geomagnetic sensor is used as the attitude angle sensor 16 to calculate the attitude angle of the vehicle. However, the present invention is not limited to this. The attitude angle of the host vehicle may be calculated using the velocity vector of the vehicle calculated by , the acceleration and angular velocity of the vehicle detected by the 6-axis gyro sensor, and the like.

FIG. 3 shows an example of the attitude angle of the own vehicle 50 at a certain time. FIG. 3(A) shows the attitude angle of the own vehicle 50 with respect to the road surface from directly above, and FIG. 3(B) shows the attitude angle of the own vehicle 50 from the side with respect to the road surface. Hereinafter, as shown in FIG. 3, it is assumed that the attitude angle of the host vehicle 50 at a certain time is yaw angle=θ (clockwise is positive with due north being zero), pitch angle=α, and roll angle=0. .

Next, as a second step, the antenna position/receiver time error calculation unit 32 determines the location of each of the GPS antennas 12A and 12B on the earth based on the calculated attitude angle of the own vehicle. , to calculate the positional relationship with the location to be positioned. Specifically, first, the antenna position/receiver time error calculation unit 32 calculates the distance between the location where each GPS antenna 12A and 12B is installed on the earth and the location to be measured, and each GPS Based on the angles of the installation locations of the antennas 12A and 12B and the detected attitude angle of the own vehicle, the absolute position relationship on the earth between the location to be measured (vehicle center) and the installation location of each GPS antenna is calculated. do. Specifically, it is calculated in the following procedure. Here, the case where the GPS antenna 12A is targeted will be described.

(Procedure 1) The positional relationship in the ENU (East-North-Up) coordinate system is calculated by the following formula (1).
FIG. 4 shows an example of the positional relationship between the location to be positioned (vehicle center) and the installation location of the GPS antenna 12A. FIG. B) shows the positional relationship viewed from the side with respect to the road surface, and FIG. 4C shows the positional relationship projected onto the ground surface (EN coordinate plane).

（１）

(1)

(Procedure 2) By converting from the ENU coordinate system to the ECEF (Earth-Centered Earth-Fixed) coordinate system according to the following equation (2), the relationship of the absolute position on the earth is calculated. Similarly, the positional relationship with the location to be measured is calculated for the location where the GPS antenna 12B is installed. Hereinafter, the calculation result of the positional relationship obtained in this way will be described as "the installation location of the GPS antenna 12A=F _A (position to be measured)".

（２）

(2)

here,

Also, α is the major axis [m] of the earth, and f is the oblateness.

Then, as a third step, the antenna position/receiver time error calculation unit 32 uses the calculated positional relationship and the acquired satellite information to calculate the position of the positioning target point on the earth and the position of each receiver. Compute the time error. Specifically, the antenna position/receiver time error calculation unit 32 uses the position of the positioning target location and the time error of each of the plurality of GPS antennas 12A and 12B as unknowns, and calculates the position of the positioning target location and the positioning target location. Using the absolute position relationship on the earth between (vehicle center) and each antenna installation location, an equation describing the location of the installation location of the plurality of GPS antennas 12A and 12B, and each of the plurality of GPS antennas 12A and 12B Based on the pseudo-range observed at each of the installation locations of the plurality of GPS antennas 12A and 12B, the position of the positioning target location and the time error of each receiver are calculated. This pseudorange is the distance between the GPS satellite and the GPS antenna according to the GPS pseudorange data.

More specifically, the total 5 of the three-dimensional position vector (x, y, z) in the ECEF coordinate system of the positioning target location and the time error (hereinafter also referred to as clock bias) of the two receivers 14A and 14B are unknown, and the three-dimensional position vectors in the ECEF coordinate system of the installation locations of the GPS antennas 12A and 12B are F _A (x, y, z) and F _B (x, y, z). (Positioning by one GPS antenna) By formulating equation (3) for each GPS antenna 12A, 12B and for each satellite (here, only the GPS antenna 12A is described. The same is true for the GPS antenna 12B. ), and the position (x, y, z) of the location to be measured is calculated using observation results from a total of five or more satellites of the GPS antennas 12A and 12B. It also calculates the time error of each of the receivers 14A and 14B. When the number of GPS antennas installed is N, the position (x, y, z) of the location to be measured is calculated using observation results from a total of (N+3) or more satellites.

・・・（３）

... (3)

Here, the position of the GPS antenna 12A is represented by the following formula.

Also, (x, y, z) is the position of the location to be positioned, and Cb _A is the clock bias [m] of the receiver 14A of the GPS antenna 12A (distance converted by multiplying by the speed of light). Also, PR _i is the observed pseudorange [m] for satellite i, and (X _si , Y _si , Z _si ) is the position of satellite i.

In this way, by appropriately considering the positional relationship between the positioning target location and the antenna installation location, the position of the positioning target location can be determined with high accuracy even when using pseudoranges observed at a location different from the positioning target location. can be calculated.

Next, as a fourth step, the antenna position/receiver time error calculation unit 32 uses the positional relationship between the installation location of the GPS antenna and the positioning target location obtained as described above, and the position of the positioning target location. , the position of each of the GPS antennas 12A, 12B. That is, by applying the position of the positioning target location on the earth calculated in the third step to the positional relationship between the installation location of each of the GPS antennas 12A and 12B and the positioning target location calculated in the second step, The position of each of the GPS antennas 12A, 12B is derived.

The estimated pseudorange calculation unit 34 estimates, for each of the GPS antennas 12A and 12B, each of all the GPS satellites from which radio waves are received in common by the GPS antennas 12A and 12B. A pseudorange (hereinafter referred to as an estimated pseudorange) is calculated. Specifically, the position of each of the GPS antennas 12A and 12B and the time error of each of the receivers 14A and 14B derived by the antenna position/receiver time error calculator 32 are substituted into equation (3). , the estimated pseudorange is calculated for each of the GPS antennas 12A and 12B.

The pseudorange residual calculator 35 calculates the difference between the observed pseudorange (hereinafter referred to as the observed pseudorange) and the estimated pseudorange (hereinafter referred to as the pseudorange residual ) is calculated. Specifically, among all the GPS satellites from which radio waves have been received, for each of all the GPS satellites from which radio waves are commonly received by the GPS antennas 12A and 12B, for each of the GPS antennas 12A and 12B, according to Equation (4), Compute the pseudorange residuals.
(residual error of pseudorange) = | (observed pseudorange) - (estimated pseudorange) | (4)

The excluded satellite determination unit 37 is used when estimating the position of the vehicle based on the difference in the pseudorange residuals of the GPS antennas 12A and 12B of each of the GPS satellites calculated by the pseudorange residual calculation unit 35. The GPS satellites to be excluded from the GPS satellites are discriminated. Specifically, the excluded satellite determination unit 37 calculates the pseudorange of the GPS antenna 12A calculated by the pseudorange residual calculation unit 35 for each of all the GPS satellites whose radio waves are commonly received by the GPS antennas 12A and 12B. A difference between the residual and the pseudorange residual of the GPS antenna 12B (hereinafter referred to as a pseudorange residual difference) is calculated. Then, a GPS satellite with a GPS antenna whose absolute value of the difference in the pseudorange residual calculated for each GPS satellite is equal to or greater than a threshold is determined as a GPS satellite to be excluded from all GPS satellites that commonly receive radio waves. do. In this way, it is possible to preliminarily exclude satellites affected by multipath errors by appropriately considering the positional relationship and velocity relationship between the positioning target location and each GNSS antenna installation location.

The position derivation unit 40 derives the position of the positioning target point on the earth using the information of the GPS satellites. Specifically, for example, the satellite information from the GPS satellites other than the excluded GPS satellites is used to calculate the position of the positioning target location. It should be noted that the derivation of the position of the location to be measured by the position derivation unit 40 can be derived, for example, by the same processing as the calculation from the first step to the third step in the antenna position/receiver time error calculation unit 32. detailed description is omitted.

As described above, by appropriately considering the positional relationship and velocity relationship between the positioning target location and each GNSS antenna installation location, and excluding satellites affected by multipath errors in advance, It is possible to calculate the position and speed of the location to be positioned with high accuracy using only the satellite information from.

Next, operation of the positioning device 10 according to the first embodiment will be described.
FIG. 5 shows an example of the contents of the satellite selection processing routine in the computer of the satellite selection device 18 in the positioning device.

When the attitude angle sensor 16 detects geomagnetism and the GPS antennas 12A, 12B and receivers 14A, 14B receive radio waves from a plurality of GPS satellites, the computer 30 of the satellite selection device 18 displays the The positioning processing routine shown is repeatedly executed.

In step S100, information of a plurality of GPS satellites is obtained from the GPS receivers 14A and 14B, and GPS pseudorange data, Doppler frequencies, and position coordinates of the GPS satellites of the plurality of GPS satellites are calculated and obtained. GPS information for a plurality of GPS satellites acquired at the same time is acquired as a GPS information group.

Next, in step S102, the positions of the installation locations of the GPS antennas 12A and 12B and the time errors of the receivers 14A and 14B are calculated.

Specifically, in the first step, the attitude angle of the own vehicle is calculated based on the detected value from the attitude angle sensor 16 . Next, in the second step, the previously obtained distances between the installation locations of the GPS antennas 12A and 12B on the earth and the locations to be positioned, the angles of the installation locations of the GPS antennas 12A and 12B, and Based on the detected attitude angle of the host vehicle, the positional relationship in the ECEF coordinate system between the location to be positioned (vehicle center) and each antenna installation location is calculated. Then, in the third stage, the position of the location to be measured and the time error of each of the receivers 14A and 14B corresponding to the plurality of GPS antennas 12A and 12B are set as unknowns, and the position of the location to be measured and the location to be measured (vehicle center) and each antenna installation location in the ECEF coordinate system, an equation describing the location of the installation location of the plurality of GPS antennas 12A and 12B, and each of the plurality of GPS antennas 12A and 12B. Based on the pseudo-range observed at each installation location of the GPS antennas 12A and 12B, the position of the location to be positioned is calculated. Also, the time errors of the receivers 14A, 14B of the GPS antennas 12A, 12B are calculated. Next, in the fourth step, the position of the positioning target location on the earth calculated in the third step is added to the positional relationship between the installation location of each of the GPS antennas 12A and 12B and the positioning target location calculated in the second step. to derive the position of each of the GPS antennas 12A, 12B.

Then, based on the GPS information group, the positions of the GPS antennas 12A and 12B, and the time errors of the receivers 14A and 14B corresponding to the GPS antennas 12A and 12B, among the GPS satellites that are commonly received, Set GPS satellites to be excluded.

Specifically, in step S106, any one GPS satellite (i = 1), and in the next step S108, using the position of each of the GPS antennas 12A and 12B and the time error of each of the receivers 14A and 14B derived in step S102, each of the GPS antennas 12A and 12B Calculate the estimated pseudorange of Next, in step S110, the absolute value obtained by subtracting the estimated pseudorange calculated in step S112 from the observed pseudorange, which is the observed pseudorange, is calculated for each of the GPS antennas 12A and 12B. is calculated (see formula (4)).

In the next step S112, the difference between the pseudorange residual of the GPS antenna 12A calculated for the corresponding GPS satellite and the pseudorange residual of the GPS antenna 12B is calculated. Then, in the next step S114, it is determined whether or not the absolute value of the pseudorange residual difference is equal to or greater than the threshold. is set as a GPS satellite to be excluded from all GPS satellites that have received radio waves, and output by the output unit 20 . This makes it possible to appropriately consider the positional relationship and velocity relationship between the positioning target location and each GNSS antenna installation location, and to preliminarily exclude satellites affected by multipath errors.

On the other hand, if the determination in step S114 is negative, the process proceeds to step S118. In step S118, it is determined whether or not the above process has been completed for all GPS satellites (i≧n) by discriminating whether or not there are GPS satellites that have not been subjected to the above process. If there are GPS satellites that have not been subjected to the above process, the result in step S118 is NO, and after setting the next GPS satellite (i=i+1) in step S120, the process returns to step S108. On the other hand, if the above process has been completed for all GPS satellites, the determination in step S118 is affirmative, and the process returns to step S100.

In the positioning device 10 according to the present embodiment, when a GPS satellite to be excluded is selected as described above, the position deriving unit 40 obtains satellite information from GPS satellites other than the selected GPS satellite to be excluded. is used to calculate the position of the location to be positioned. As a result, the position on the earth can be accurately calculated by excluding GPS satellites that are presumed to have been affected by multipath errors for positioning target locations that are different from the locations where multiple GPS antennas are installed on the vehicle. be able to.

As described above, according to the positioning device according to the first embodiment, the satellite selection device 18 appropriately considers the positional relationship between the positioning target location and each GPS antenna installation location, and determines the effects of multipath errors. By preliminarily excluding the GPS satellites that are presumed to have received the signal, it is possible to accurately calculate the position on the earth of the location to be positioned on the vehicle.

In addition, even if the positioning target point is not the center of gravity of each GPS antenna installation point, or even if the positioning target point and each GPS antenna installation point are far apart, the position of the positioning target point can be calculated with high accuracy. is possible.

<Second embodiment>
Next, a second embodiment will be described. In addition, regarding the positioning device of the second embodiment, the same components as those of the positioning device 10 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the second embodiment, only when the reliability of the calculated time errors of the receivers 14A and 14B is high, GPS satellites estimated to be affected by multipath errors are excluded in advance. is mainly different from the embodiment of

FIG. 6 shows an example of the configuration of a positioning device according to the second embodiment.
As shown in FIG. 6, the computer 230 of the satellite selection device 218 in the positioning device 210 according to the second embodiment includes a satellite information acquisition unit 31, an antenna position/receiver time error calculation unit 32, an estimated pseudorange calculation unit 34 , a pseudorange residual calculation unit 35 , a receiver time error reliability determination unit 232 , and an excluded satellite determination unit 237 . The receiver time error reliability determination unit 232 is an example of the reliability determination unit of the present disclosure.

The receiver time error reliability determination unit 232 determines the reliability of the receiver time error calculated by the antenna position/receiver time error calculation unit 32 . Specifically, the reliability of the time error of the receiver may be determined according to the variation of the pseudorange residual in the GPS antenna. For example, an error in the receiver's time error will have a common effect on each pseudorange residual for all GPS satellites. Therefore, when the pseudorange residuals for all GPS satellites are larger than a certain level, there is a high possibility that the time error calculation of the receiver is erroneous, that is, the reliability is considered to be low. On the other hand, if the pseudorange residuals for all GPS satellites are less than a certain value, it is considered that there is a low possibility that the time error calculation of the receiver is erroneous, that is, the reliability is high.

More specifically, the receiver time error reliability determination unit 232 uses the pseudorange residual calculated by the pseudorange residual calculation unit 35 to determine all For GPS satellites, pseudorange residuals are calculated for each GPS antenna. Next, for all GPS satellites that are commonly received, if the pseudorange residual of one GPS antenna is greater than the pseudorange residual of the other GPS antenna by a predetermined threshold or more, the pseudorange residual is It is determined that the reliability of the time error of the receiver connected to the larger GPS antenna is low. This is because an error in the calculation of the time error of the receiver commonly affects the pseudorange residuals of all GPS satellites that are commonly received, so that the pseudorange residuals for all GPS satellites are This is because it is highly likely that the time error calculation of the receiver is erroneous if it is greater than a certain amount. Also, if the pseudorange residual of one GPS antenna is less than the threshold relative to the pseudorange residual of the other GPS antenna, it means that the reliability of the time error of the receiver connected to the GPS antenna is high. judge.

The excluded satellite determination unit 237 determines the GPS antenna of each GPS satellite calculated by the pseudorange residual calculation unit 35 based on the reliability of the receiver time error determined by the receiver time error reliability determination unit 232. A GPS satellite to be excluded from the GPS satellites to be used for estimating the position of the vehicle is determined from the difference between the pseudorange residuals of 12A and 12B.

Specifically, when the pseudorange residuals for all GPS satellites are less than the threshold and the receiver time error reliability determination unit 232 determines that the reliability of the receiver time error is high, As in the first embodiment, GPS satellites to be excluded are determined based on the difference in the pseudorange residuals of the GPS antennas 12A and 12B of all the GPS satellites.

On the other hand, if the pseudorange residuals for all GPS satellites are equal to or greater than the threshold and the receiver time error reliability determination unit 232 determines that the reliability of the receiver time error is low, the GPS satellites to be excluded Do not discriminate. For example, the GPS satellites received by any of the GPS antennas 12A and 12B are output without being excluded.

In this manner, satellite selection similar to that of the first embodiment is performed only when it is determined that the reliability of the time error is high in both receivers of the GPS antennas 12A and 12B. This allows for pre-exclusion of satellites affected by multipath errors, taking into account the reliability of the receiver's time error determined based on the pseudorange residuals for all GPS satellites. .

Next, operation of the positioning device 210 according to the second embodiment will be described. It should be noted that the same reference numerals are assigned to portions that are processed in the same manner as in the first embodiment, and detailed description thereof will be omitted.
FIG. 7 shows an example of the contents of a satellite selection processing routine in the computer of the satellite selection device 18 as main processing in the positioning device according to the second embodiment.

While the GPS antennas 12A, 12B and the receivers 14A, 14B are receiving radio waves from a plurality of GPS satellites, the computer 230 repeatedly executes the positioning processing routine shown in FIG.

In step S100, information of a plurality of GPS satellites is obtained from the GPS receivers 14A and 14B, and GPS pseudorange data, Doppler frequencies, and position coordinates of the GPS satellites of the plurality of GPS satellites are calculated and obtained. GPS information for a plurality of GPS satellites acquired at the same time is acquired as a GPS information group.

Next, in the same manner as described above, in step S102, the positions of the installation locations of the GPS antennas 12A and 12B and the time errors of the receivers 14A and 14B of the GPS antennas 12A and 12B are calculated. Then, among the GPS satellites commonly received by each of the GPS antennas 12A and 12B, the GPS satellites to be excluded are set.

First, in step S106, any one GPS satellite is set among all the GPS satellites from which radio waves are commonly received by the plurality of GPS antennas 12A and 12B. Then, in step S108, estimated pseudoranges for each of the GPS antennas 12A and 12B are calculated, and in step S110, pseudorange residuals are calculated for each of the GPS antennas 12A and 12B.

In step S200, it is determined whether or not the above processes have been completed for all GPS satellites by determining whether or not there remain GPS satellites that have not yet been subjected to the estimated pseudorange and pseudorange residual calculation processing. . If there are GPS satellites that have not been subjected to the above process, the result in step S200 is NO, and after setting the next GPS satellite in step S202, the process returns to step S200. On the other hand, if the above process has been completed for all GPS satellites, the result of step S200 is affirmative, and the process proceeds to step S204.

In step S204, it is determined whether or not there is a GPS antenna with a pseudorange residual equal to or greater than a threshold among the pseudorange residuals for each GPS antenna for all GPS satellites commonly received by the GPS antennas 12A and 12B. do. If there is a GPS antenna whose pseudorange residual is equal to or greater than the threshold, the result of step S204 is affirmative, and the process returns to step S100 without executing the process of selecting GPS satellites to be excluded, which will be described later. On the other hand, if all of the pseudorange residuals are less than the threshold, the result in step S204 is negative, and the process proceeds to step S206 to select GPS satellites to be excluded.

In step S206, any one GPS satellite is set among all the GPS satellites from which radio waves are commonly received by the plurality of GPS antennas 12A and 12B. Then, in step S108, estimated pseudoranges for each of the GPS antennas 12A and 12B are calculated, and in step S110, pseudorange residuals are calculated for each of the GPS antennas 12A and 12B.

In the next step S208, a pseudorange residual difference between the pseudorange residual of the GPS antenna 12A and the pseudorange residual of the GPS antenna 12B is calculated. In the next step S210, it is determined whether or not the absolute value of the difference of the pseudorange residuals is equal to or greater than the threshold.If the determination is affirmative, in step S212, radio waves are commonly received from the currently set GPS satellites. It is set as a GPS satellite to be excluded from all GPS satellites and output by the output unit 20 . This allows the satellites affected by multipath errors to be excluded in advance, taking into account the reliability of the receiver's time error.

On the other hand, if the determination in step S210 is negative, the process proceeds to step S214. In step S214, it is determined whether or not the above process has been completed for all GPS satellites by determining whether there are GPS satellites that have not been subjected to the above process. If there are GPS satellites that have not been subjected to the above process, the result in step S214 is NO, and after setting the next GPS satellite in step S216, the process returns to step S208. On the other hand, if execution of the above process has been completed for all GPS satellites, affirmative determination is made in step S214, and the process returns to step S100.

As described above, according to the positioning device according to the second embodiment, the satellite selection device 18 selects the positioning target location only when the reliability of the time error of the receiver connected to the GPS antenna is high. By appropriately considering the positional relationship with each GPS antenna installation location and excluding in advance GPS satellites that are presumed to have been affected by multipath errors, the position of the target location on the vehicle can be accurately determined on the earth. can be calculated well.

<Third Embodiment>
Next, a third embodiment will be described. In the third embodiment, an example will be described in which the technology of the present disclosure is applied to a speed measuring device that calculates the speed of the own vehicle. In the velocity measuring device of the third embodiment, the same components as those of the positioning device 10 of the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

FIG. 8 shows an example of the configuration of a velocity measuring device according to the third embodiment.
As shown in FIG. 8, a velocity measuring device 310 according to the third embodiment includes a plurality of GPS antennas 12A and 12B, a plurality of receivers 14A and 14B, an attitude angle sensor 16, a gyro sensor 316, a plurality of A satellite selection device 318 that selects a GPS satellite to be used based on the received signals from the GPS satellites received by the receivers 14A and 14B and the detection values of the attitude angle sensor 16 and the gyro sensor 316; and a speed derivation unit 340 that executes speed derivation processing for deriving . The satellite selection device 318 includes a computer 330 that performs satellite selection processing for selecting GPS satellites to be used to derive the speed of the host vehicle, and an output unit 20 .

When the computer 330 is represented by functional blocks, as shown in FIG. 8, a satellite information acquisition unit 31, an antenna velocity/receiver time error change amount calculation unit 332, an estimated Doppler frequency calculation unit 334, and a Doppler frequency residual calculation unit A section 335 and an exclusion satellite determination section 337 are provided. The satellite information acquisition unit 31 according to the third embodiment is an example of the satellite information acquisition unit and observed Doppler frequency derivation unit of the present disclosure. The estimated Doppler frequency calculator 334 is an example of the estimated Doppler frequency derivation unit of the present disclosure. The Doppler frequency residual calculator 335 is an example of the residual derivation unit of the present disclosure. The excluded satellite determination unit 337 is an example of the satellite selection unit of the present disclosure.

The antenna speed/receiver time error change amount calculation unit 332 calculates the speed relationship between the installation location on the earth of each of the GPS antennas 12A and 12B and the positioning target location calculated based on the attitude angle of the own vehicle, and the acquired satellite The velocity of each of the GPS antennas 12A and 12B is calculated based on the velocity of the location to be determined using the information. Also, the amount of change in the time error of the receivers 14A and 14B of the GPS antennas 12A and 12B (hereinafter referred to as clock drift) is calculated.

Specifically, the antenna velocity/receiver time error change amount calculator 332 calculates the angular velocity of the host vehicle at the time by using the detection value of the gyro sensor 316 as the first step. Next, the antenna velocity/receiver time error change amount calculator 332 calculates the attitude angle of the host vehicle from the detection value of the attitude angle sensor 16 as a second step.
FIG. 9 shows an example of the attitude angle of the own vehicle 50 at a certain time. FIG. 9A shows the attitude angle of the own vehicle 50 with respect to the road surface from directly above, and FIG. 9B shows the attitude angle of the own vehicle 50 from the side with respect to the road surface. Hereinafter, as shown in FIG. 9, the angular velocity at a certain time is yaw rate=ω, pitch rate=0, roll rate=0, and the attitude angle is yaw angle=θ ), pitch angle=α, and roll angle=0.

Next, as a third step, the antenna velocity/receiver time error change amount calculation unit 332 calculates the GPS antenna 12A, 12B, the velocity relationship between the location where the GPS antenna is installed on the earth and the location to be positioned is calculated.
Specifically, first, the antenna velocity/receiver time error change amount calculation unit 332 calculates the distance between the installation location of each GPS antenna 12A and 12B on the earth and the location to be measured, which is obtained in advance, and Based on the angles of the installation locations of the GPS antennas 12A and 12B and the detected attitude angle and angular velocity of the own vehicle, the velocity relationship on the earth between the location to be positioned (vehicle center) and each GPS antenna installation location is calculated. calculate. More specifically, it is calculated by the following procedure. Here, the case where the GPS antenna 12A is targeted will be described.

(Procedure 1) The velocity relationship in the ENU (East-North-Up) coordinate system is calculated by the following formula (5).
FIG. 10 shows an example of the speed relationship between the location to be positioned (vehicle center) and the location where the GPS antenna 12A is installed. 10(B) shows the velocity relationship when viewed from the side of the road surface, and FIG. 10(C) shows the velocity relationship when viewed on the ground surface (EN coordinate plane).

（５）

(5)

(Procedure 2) A velocity relationship on the earth is calculated by converting from the ENU coordinate system to the ECEF (Earth-Centered Earth-Fixed) coordinate system by the following formula (6). Similarly, the speed relationship with the position to be measured is calculated for the location where the GPS antenna 12B is installed. Hereinafter, the calculation result of the velocity relationship obtained in this manner will be expressed as "velocity at location where GPS antenna _12A is installed=GA (velocity at location to be measured)".

（６）

(6)

here,

Also, α is the major axis [m] of the earth, and f is the oblateness.

Then, as a fourth step, the antenna speed/receiver time error change amount calculation unit 332 uses the calculated speed relationship and the acquired satellite information to calculate the speed of the location to be positioned on the earth and a plurality of Calculate the receiver clock drift for each of the GPS antennas.
Specifically, the antenna velocity/receiver time error change amount calculation unit 332 uses the velocity of the location to be measured and the time error of each of the plurality of GPS antennas 12A and 12B as unknowns, and the velocity of the location to be measured and the positioning Using the velocity relationship on the earth between the target location (vehicle center) and each antenna installation location, an equation describing the velocity of the installation location of the plurality of GPS antennas 12A and 12B, and each of the plurality of GPS antennas 12A and 12B Based on the relative velocity with the satellite obtained from the Doppler frequency observed at each installation location of the plurality of GPS antennas 12A and 12B, the velocity of the positioning target location and the clock drift of each receiver are calculated. .

More specifically, the three-dimensional velocity vector (Vx, Vy, Vz) in the ECEF coordinate system of the positioning target location, and the clock drift, which is the amount of change in the clock bias of the two receivers 14A and 14B, are five in total. is an unknown quantity, and the three-dimensional velocity vectors in the ECEF coordinate system of the installation locations of the GPS antennas 12A and 12B are G _A (Vx, Vy, Vz) and G _B (Vx, Vy, Vz), and the known By formulating equation (7) for each GPS antenna 12A, 12B and for each satellite (here, only the GPS antenna 12A is described. GPS The same applies to the antenna 12B), and the velocities (Vx, Vy, Vz) of the location to be positioned are calculated using observation results from a total of five or more satellites of the GPS antennas 12A and 12B. An example of velocity calculation using a single GPS antenna is described in Y. Kojima, "Proposal for a new localization method using tightly coupled integration based on a precise estimation of trajectory from GPS Doppler", Proceedings of AVEC2010, Laughborough UK, 2010. ) can be mentioned. If the number of GPS antennas installed is N, the velocity (Vx, Vy, Vz) and clock drift of the positioning target location are calculated using observation results from a total of (N+3) or more satellites. .

・・・（７）

... (7)

Here, the speed of the GPS antenna 12A is represented by the following formula.

Also, (Vx, Vy, Vz) is the velocity of the location to be positioned, and Cbv _A is the clock drift [m/s] of the receiver 14A of the GPS antenna 12A (converted to velocity by multiplying by the speed of light). . (x _A , y _A , z _A ) is the position of the GPS antenna 12A. Also, D _i is the Doppler frequency [Hz] observed for satellite i, (X _si , Y _si , Z _si ) is the position of satellite i, and r _i is expressed by the following equation.

Also, f ₁ is the carrier frequency (1575.42×10 ⁶ ) [Hz], C is the speed of light (2.99792458×10 ⁸ ) [m/s], and (V _xsi , V _ysi , V _zsi ) is the satellite is the velocity of i.

In this way, by appropriately considering the velocity relationship between the location to be determined and the location where the antenna is installed, even if Doppler frequencies observed at locations different from the location to be determined are used, the velocity of the location to be determined can be determined with high accuracy. can be calculated.

Next, as a fifth step, the antenna speed/receiver time error change amount calculation unit 332 calculates the velocity relationship between the installation location of the GPS antenna and the positioning target location obtained as described above, and the position of the positioning target location. is used to derive the velocity of each of the GPS antennas 12A, 12B. That is, by applying the speed of the positioning target location on the earth calculated in the fourth step to the speed relationship between the installation location of each of the GPS antennas 12A and 12B and the positioning target location calculated in the third step, Derive the velocity of each of the GPS antennas 12A, 12B.

The estimated Doppler frequency calculator 334 estimates for each of the GPS antennas 12A and 12B, among all the GPS satellites from which radio waves are received, all GPS satellites from which radio waves are commonly received by the GPS antennas 12A and 12B. A Doppler frequency (hereinafter referred to as an estimated Doppler frequency) is calculated. Specifically, the speed of each of the GPS antennas 12A and 12B and the clock drift of each of the receivers 14A and 14B derived by the antenna speed/receiver time error variation calculator 332 are substituted into equation (7). By doing so, the estimated Doppler frequency is calculated for each of the GPS antennas 12A and 12B.

The Doppler frequency residual calculator 335 calculates the difference between the observed Doppler frequency (hereinafter referred to as the observed Doppler frequency) and the estimated estimated Doppler frequency (hereinafter referred to as the Doppler frequency residual) for each of the GPS antennas 12A and 12B. ) is calculated. Specifically, among all the GPS satellites from which radio waves have been received, for each of all the GPS satellites from which radio waves are commonly received by the GPS antennas 12A and 12B, for each of the GPS antennas 12A and 12B, according to Equation (8), Calculate the Doppler frequency residual.
(Doppler frequency residual) = | (Observed Doppler frequency) - (Estimated Doppler frequency) |
... (8)

The excluded satellite determination unit 337 is used when estimating the speed of the own vehicle based on the difference between the Doppler frequency residuals of the GPS antennas 12A and 12B of each of the GPS satellites calculated by the Doppler frequency residual calculation unit 335. The GPS satellites to be excluded from the GPS satellites are discriminated. Specifically, the excluded satellite determination unit 337 determines the Doppler frequency of the GPS antenna 12A calculated by the Doppler frequency residual calculation unit 335 for each of all the GPS satellites whose radio waves are commonly received by the GPS antennas 12A and 12B. A difference between the residual and the Doppler frequency residual of the GPS antenna 12B (hereinafter referred to as the Doppler frequency residual difference) is calculated. Then, a GPS satellite with a GPS antenna whose absolute value of the difference in Doppler frequency residual calculated for each GPS satellite is equal to or greater than a threshold is discriminated as a GPS satellite to be excluded from all GPS satellites that commonly receive radio waves. do. In this way, it is possible to preliminarily exclude satellites affected by multipath errors by appropriately considering the velocity relationship between the positioning target location and each GNSS antenna installation location.

Velocity derivation unit 340 derives the velocity of a location to be positioned on the earth using GPS satellite information. Specifically, for example, the satellite information from the GPS satellites other than the excluded GPS satellites is used to calculate the velocity of the positioning target location. It should be noted that the derivation of the velocity of the location to be measured by the velocity derivation unit 340 can be derived, for example, by the same processing as the calculation from the first step to the fourth step in the antenna velocity/receiver time error change amount calculation unit 332. , detailed description is omitted.

As described above, by appropriately considering the velocity relationship between the positioning target location and each GNSS antenna installation location and excluding satellites affected by multipath errors in advance, satellite Using only the information, it is possible to calculate the position and speed of the location to be positioned with high accuracy.

Next, the action of the speed measuring device 310 according to the third embodiment will be described.
FIG. 11 shows an example of the contents of the satellite selection processing routine in the computer of the satellite selection device 318 in the velocity measurement device.

Attitude angle sensor 16 detects geomagnetism, gyro sensor 316 detects angular acceleration, and GPS antennas 12A, 12B and receivers 14A, 14B receive radio waves from a plurality of GPS satellites. In computer 330 of device 318, the velocity measurement processing routine shown in FIG. 11 is repeatedly executed.

In step S300, information on a plurality of GPS satellites is obtained from the GPS receivers 14A and 14B, and GPS pseudorange data, Doppler frequencies, and position coordinates of the GPS satellites are calculated and obtained for the plurality of GPS satellites. GPS information for a plurality of GPS satellites acquired at the same time is acquired as a GPS information group.

Next, in step S302, the speed at each installation location of the GPS antennas 12A and 12B is calculated. Specifically, in the first step, the detected value of the gyro sensor 316 is used to calculate the angular velocity of the vehicle at that time, and in the second step, the detected value of the attitude angle sensor 16 is used to Calculate In the next third step, for each of the GPS antennas 12A and 12B, the velocity relationship between the installation location of the GPS antenna on the earth and the location to be positioned is calculated. In the next fourth step, using the calculated velocity relationship and the acquired satellite information, the velocity of the location to be positioned on the earth is calculated. It also calculates the clock drift of the receivers 14A, 14B of each of the GPS antennas 12A, 12B. Then, in the fifth step, the velocity of each of the GPS antennas 12A and 12B is derived using the velocity relationship between the location where the GPS antenna is installed and the location to be measured and the position of the location to be determined.

Then, based on the GPS information group, the positions of the GPS antennas 12A and 12B, and the clock drifts of the receivers 14A and 14B corresponding to the GPS antennas 12A and 12B, among the GPS satellites that are commonly received, Set GPS satellites to be excluded.

Specifically, in step S306, any one GPS satellite (i=1 ), and in the next step S308, using the velocity of each of the GPS antennas 12A, 12B and the clock drift of each of the receivers 14A, 14B derived in step S304, Calculate the estimated Doppler frequency. Next, in step S310, the absolute value obtained by subtracting the estimated Doppler frequency calculated in step S308 from the observed Doppler frequency, which is the observed Doppler frequency, is calculated for each of the GPS antennas 12A and 12B. is calculated (see formula (8)).

In the next step S312, the difference between the Doppler frequency residual of the GPS antenna 12A calculated for the corresponding GPS satellite and the Doppler frequency residual of the GPS antenna 12B is calculated. Then, in the next step S314, it is determined whether or not the absolute value of the Doppler frequency residual difference is equal to or greater than the threshold. is set as a GPS satellite to be excluded from all GPS satellites that have received radio waves, and output by the output unit 20 . This makes it possible to appropriately consider the positional relationship and velocity relationship between the positioning target location and each GNSS antenna installation location, and to preliminarily exclude satellites affected by multipath errors.

On the other hand, if the determination in step S314 is negative, the process proceeds to step S318. In step S318, it is determined whether or not the above process has been completed for all GPS satellites (i≧n) by determining whether or not there are any GPS satellites that have not been subjected to the above process. If there are GPS satellites that have not been subjected to the above process, the result in step S318 is NO, and after setting the next GPS satellite (i=i+1) in step S320, the process returns to step S308. On the other hand, if the above process has been completed for all GPS satellites, affirmative determination is made in step S318, and the process returns to step S300.

In the speed measuring device 310 according to the present embodiment, when a GPS satellite to be excluded is selected as described above, the speed derivation unit 340 obtains satellite information from GPS satellites other than the selected GPS satellite to be excluded. is used to calculate the velocity of the location to be positioned. As a result, GPS satellites that are presumed to have been affected by multipath errors are excluded in advance for positioning targets that are different from the locations where multiple GPS antennas are installed on the vehicle, thereby accurately calculating velocities on the earth. be able to.

As described above, according to the speed measurement device according to the third embodiment, the satellite selection device 318 appropriately considers the speed relationship between the positioning target location and each GPS antenna installation location, and calculates the multipath error. By preliminarily excluding the GPS satellites that are presumed to have been affected, it is possible to accurately calculate the velocity on the earth for the location to be positioned on the vehicle.

<Fourth Embodiment>
Next, a fourth embodiment will be described. In the speed measuring device of the fourth embodiment, the same components as those of the speed measuring device 310 of the third embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

The fourth embodiment differs from the third embodiment in that GPS satellites that are estimated to be affected by multipath errors are excluded in advance only when the reliability of the calculated clock drift of each receiver is high. differ mainly in morphology.

FIG. 12 shows an example of the configuration of the velocity measuring device according to the fourth embodiment.
As shown in FIG. 12, the computer 430 of the satellite selection device 418 in the speed measurement device 410 according to the fourth embodiment includes a satellite information acquisition unit 31, an antenna speed/receiver time error change amount calculation unit 332, an estimation A Doppler frequency calculator 334 , a Doppler frequency residual calculator 335 , a receiver clock drift reliability determiner 436 , and an excluded satellite determiner 437 are provided. Receiver clock drift reliability determiner 436 is an example of a reliability determiner of the present disclosure.

The receiver clock drift reliability determination unit 436 determines the reliability of the receiver clock drift calculated by the antenna velocity/receiver time error change amount calculation unit 332 . Specifically, the reliability of the clock drift of the receiver may be determined according to the variation of the Doppler frequency residual in the GPS antenna. For example, an error in receiver clock drift will have a common effect on each Doppler frequency residual of all GPS satellites. Therefore, if the Doppler frequency residuals for all GPS satellites are larger than a certain level, it is highly likely that the receiver's calculation of the clock drift is erroneous, that is, the reliability is low. On the other hand, if the Doppler frequency residuals for all GPS satellites are less than a certain value, it is considered that the receiver's clock drift calculation is unlikely to be erroneous, that is, the reliability is high.

More specifically, the receiver clock drift reliability determination unit 436 uses the Doppler frequency residual calculated by the Doppler frequency residual calculation unit 335 to determine all For the GPS satellites, the Doppler frequency residual is calculated for each GPS antenna. Next, for all GPS satellites that are commonly received, if the Doppler frequency residual of one GPS antenna is larger than the Doppler frequency residual of the other GPS antenna by a predetermined threshold or more, the Doppler frequency It is determined that the clock drift of the receiver connected to the GPS antenna with the larger residual is less reliable. This is because an error in the calculation of the clock drift of the receiver commonly affects the Doppler frequency residuals of all GPS satellites that are being received in common. This is because it is highly likely that the calculation of the clock drift of the receiver in question is erroneous when is greater than a certain level. In addition, if the Doppler frequency residual of one GPS antenna is less than the threshold for the Doppler frequency residual of the other GPS antenna, the reliability of the clock drift of the receiver connected to the GPS antenna is judged to be high.

The excluded satellite determination unit 437 determines the GPS antenna of each GPS satellite calculated by the Doppler frequency residual calculation unit 335 based on the receiver clock drift reliability determined by the receiver clock drift reliability determination unit 436. A GPS satellite to be excluded from the GPS satellites to be used when estimating the speed of the own vehicle is discriminated from the difference between the Doppler frequency residuals of 12A and 12B.

Specifically, when the Doppler frequency residuals for all GPS satellites are less than the threshold and the receiver clock drift reliability determination unit 436 determines that the reliability of the receiver clock drift is high, the As in the third embodiment, GPS satellites to be excluded are determined based on the differences in Doppler frequency residuals of the GPS antennas 12A and 12B of all GPS satellites.

On the other hand, if the Doppler frequency residuals for all GPS satellites are equal to or greater than the threshold and the receiver clock drift reliability determination unit 436 determines that the reliability of the receiver clock drift is low, the GPS satellites to be excluded Do not discriminate. For example, the GPS satellites received by either of the GPS antennas 12A and 12B are output without being excluded.

In this manner, satellite selection similar to that of the third embodiment is performed only when it is determined that the reliability of the clock drift is high in both receivers of the GPS antennas 12A and 12B. This allows for pre-exclusion of satellites affected by multipath errors considering the reliability of the receiver clock drift determined based on the Doppler frequency residuals for all GPS satellites. .

Other configurations and actions of the speed measuring device 410 according to the fourth embodiment are the same as those of the second and third embodiments, and thus description thereof is omitted.

As described above, according to the speed measuring device according to the fourth embodiment, only when the reliability of the detected clock drift of the receiver of the own vehicle is high, the speed of the location to be positioned on the earth is calculated. By doing so, it is possible to stably calculate the velocity on the earth for the location to be positioned.

In the above embodiments, the case where the technology of the present disclosure is applied to the positioning device or the speed measuring device mounted on a vehicle has been described as an example, but the movement in which the positioning device or the speed measuring device of the present disclosure is mounted is described as an example. Bodies are not limited to vehicles. For example, a positioning device or a speed measuring device may be mounted on the robot.

Further, in the above embodiment, the case where the technique of the present disclosure is applied to the positioning device or the speed measuring device mounted on the vehicle has been described as an example. and velocity, the technique of the present disclosure may be applied.

Also, the case of using GPS as a satellite navigation system has been described as an example, but other satellite positioning systems (GLONASS, BeiDou, Galileo, QZSS) may be used, or these may be used in combination.

10, 210 positioning devices 12A, 12B GPS antennas 14A, 14B receiver 16 attitude angle sensors 18, 218, 318, 418 satellite selection device 20 output units 30, 230, 330, 340 computer 31 satellite information acquisition unit 32 antenna position/reception Machine time error calculator 34 Estimated pseudorange calculator 35 Pseudorange residual calculator 37 Excluded satellite discriminator 40 Position derivation unit 310, 410 Speed measuring device

Claims (8)

A satellite selection device for selecting a satellite to be used in a positioning device for calculating a position on the earth of a location to be positioned on a mobile body different from installation locations of a plurality of satellite antennas installed on the mobile body,
a satellite information acquisition unit for acquiring satellite information including information on the position of each of the plurality of satellites transmitted from each of the plurality of satellites and information on the distance between each of the plurality of satellites and the mobile object; ,
based on the satellite information acquired by the satellite information acquisition unit, between each of the plurality of satellites and each of the plurality of satellite antennas observed at each installation location of the plurality of satellite antennas; an observation pseudorange derivation unit for deriving observation pseudorange information indicating a distance;
calculating each of the plurality of satellites based on a predetermined positional relationship between the installation location of each of the plurality of satellite antennas and the positioning target location and the satellite information acquired by the satellite information acquiring unit; an estimated pseudo-range calculation unit for estimating estimated pseudo-range information indicating the distance between each of the plurality of satellite antennas by each position from the positioning target location to be determined;
the observed pseudorange information derived by the observed pseudorange derivation unit and the estimated pseudorange estimated by the estimated pseudorange calculation unit for each of the plurality of satellite antennas for each of the plurality of satellites; a residual derivation unit for deriving residuals with information;
a reliability determination unit that determines the reliability of each time error of each receiver of the plurality of satellite antennas;
Excluded from the satellites to be used based on the difference of the residuals of each of the plurality of satellite antennas derived by the residual derivation unit only when the reliability determination unit determines that the reliability is high a satellite selection unit for selecting a satellite to
Satellite selection device including. 2. The satellite selection device according to claim 1, wherein the satellite selection unit excludes satellites corresponding to residual differences equal to or greater than a predetermined threshold from the satellites to be used. The reliability determination unit determines that the residual of any one of the residuals derived by the residual derivation unit is equal to the residual of the other satellite antenna for a predetermined number of different satellites. Determine that the reliability of the time error of the receiver is high if it is within the threshold for
A satellite selection device according to claim 1 or claim 2 . A satellite selection device for selecting a satellite to be used in a speed measuring device for calculating the speed on the earth of a location to be positioned on a mobile object different from installation locations of a plurality of satellite antennas installed on the mobile object,
A satellite information acquisition unit for acquiring satellite information including information on the position of each of the plurality of satellites transmitted from each of the plurality of satellites and information on the relative velocity between each of the plurality of satellites and the mobile object. When,
based on the satellite information acquired by the satellite information acquisition unit, between each of the plurality of satellites and each of the plurality of satellite antennas observed at each installation location of the plurality of satellite antennas; an observed Doppler frequency derivation unit for deriving observed Doppler frequency information indicating relative velocity;
each of the plurality of satellites and the plurality of satellites based on the velocity relationship between the installation location of each of the plurality of satellite antennas and the positioning target location and the satellite information acquired by the satellite information acquisition unit; an estimated Doppler frequency calculator for estimating estimated Doppler frequency information indicative of relative velocity between each of the antennas;
the observed Doppler frequency information derived by the observed Doppler frequency deriving unit and the estimated Doppler frequency estimated by the estimated Doppler frequency calculator for each of the plurality of satellite antennas for each of the plurality of satellites; a residual derivation unit for deriving residuals with information;
a reliability determination unit that determines the reliability of each amount of change in the time error of each receiver of the plurality of satellite antennas;
Only when the reliability determination unit determines that the reliability is high , based on the residual difference of each of the plurality of satellite antennas derived by the residual derivation unit of each of the plurality of satellites , a satellite selection unit that selects a satellite to be used from a plurality of satellites;
Satellite selection device including. The satellite selection unit excludes from the satellites to be used a satellite corresponding to the residual difference equal to or larger than a predetermined threshold.
5. A satellite selection device according to claim 4 . The reliability determination unit determines that, of the residuals derived by the residual derivation unit, for a predetermined number of different satellites, the residual of any one of the plurality of satellite antennas is the residual of the other satellite antennas. If the residual error of the satellite antenna is within the threshold, it is determined that the reliability of the amount of change in the time error of the receiver is high
A satellite selection device according to claim 4 or claim 5 . A program for selecting a satellite to be used in a positioning device for calculating the position on the earth of a location to be positioned on a mobile body different from installation locations of a plurality of satellite antennas installed on the mobile body,
the computer,
a satellite information acquisition unit that acquires satellite information including information on the position of each of the plurality of satellites transmitted from each of the plurality of satellites and information on the distance between each of the plurality of satellites and the mobile object;
based on the satellite information acquired by the satellite information acquisition unit, between each of the plurality of satellites and each of the plurality of satellite antennas observed at each installation location of the plurality of satellite antennas; an observation pseudorange derivation unit for deriving observation pseudorange information indicating a distance;
calculating each of the plurality of satellites based on a predetermined positional relationship between the installation location of each of the plurality of satellite antennas and the positioning target location and the satellite information acquired by the satellite information acquiring unit; an estimated pseudo-range calculation unit for estimating estimated pseudo-range information indicating the distance between each of the plurality of satellite antennas by each position from the location to be measured,
the observed pseudorange information derived by the observed pseudorange derivation unit and the estimated pseudorange estimated by the estimated pseudorange calculation unit for each of the plurality of satellite antennas for each of the plurality of satellites; a residual derivation unit for deriving a residual with information;
a reliability determination unit that determines the reliability of each time error of the receiver of each of the plurality of satellite antennas; and
Excluded from the satellites to be used based on the difference of the residuals of each of the plurality of satellite antennas derived by the residual derivation unit only when the reliability determination unit determines that the reliability is high a satellite selection unit for selecting a satellite to
A program to function as A program for selecting a satellite to be used in a speed measuring device that calculates the speed on the earth of a location to be positioned on a mobile object that is different from installation locations of a plurality of satellite antennas installed on the mobile object,
the computer,
A satellite information acquisition unit for acquiring satellite information including information on the position of each of the plurality of satellites transmitted from each of the plurality of satellites and information on the relative velocity between each of the plurality of satellites and the mobile object. ,
based on the satellite information acquired by the satellite information acquisition unit, between each of the plurality of satellites and each of the plurality of satellite antennas observed at each installation location of the plurality of satellite antennas; an observed Doppler frequency derivation unit for deriving observed Doppler frequency information indicative of relative velocity;
each of the plurality of satellites and the plurality of satellites based on the velocity relationship between the installation location of each of the plurality of satellite antennas and the positioning target location and the satellite information acquired by the satellite information acquisition unit; an estimated Doppler frequency calculator for estimating estimated Doppler frequency information indicative of relative velocity between each of the antennas;
the observed Doppler frequency information derived by the observed Doppler frequency deriving unit and the estimated Doppler frequency estimated by the estimated Doppler frequency calculator for each of the plurality of satellite antennas for each of the plurality of satellites; a residual derivation unit for deriving a residual with information;
a reliability determination unit that determines the reliability of each amount of change in the time error of each receiver of the plurality of satellite antennas;
Only when the reliability determination unit determines that the reliability is high,
a satellite selection unit that selects a satellite to be used from a plurality of satellites based on the difference in the residual of each of the plurality of satellite antennas derived by the residual derivation unit for each of the plurality of satellites;
A program to function as

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