WO2008065915A1 - Mobile position positioning device - Google Patents
Mobile position positioning device Download PDFInfo
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- WO2008065915A1 WO2008065915A1 PCT/JP2007/072315 JP2007072315W WO2008065915A1 WO 2008065915 A1 WO2008065915 A1 WO 2008065915A1 JP 2007072315 W JP2007072315 W JP 2007072315W WO 2008065915 A1 WO2008065915 A1 WO 2008065915A1
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- satellite
- pseudo
- pseudo distance
- vehicle
- moving body
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
- G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/40—Correcting position, velocity or attitude
Definitions
- the present invention relates to a moving body position positioning device that measures the position of a moving body based on satellite signals.
- a technique is known that removes high-frequency fluctuations in the pseudorange by filtering the difference (see, for example, Patent Document 1). This type of filtering is known as so-called carrier smoothing.
- Patent Document 1 JP-A-7-198821
- Navigation Satellite System eliminates the function of measuring the carrier phase of the satellite signal, so the pseudo-range variation used for filtering (smoothing) from the Doppler component of the satellite signal carrier from the GPS satellite signal Cannot be calculated. Therefore, if the GNSS receiver, which is powerful and inexpensive, can calculate the pseudorange change by another means and perform pseudorange filtering, the positioning accuracy can be improved, which is useful. . Also, GNSS receivers equipped with a function to measure the carrier wave phase of satellite signals may degrade the Doppler component measurement accuracy depending on the surrounding environment when mounted on a mobile object. It is useful to enable pseudorange filtering by calculating the pseudorange change by other means other than the measurement result of the carrier phase. [0004] In particular, when the moving body is stopped!
- the present invention provides a pseudo-range filter by estimating the pseudo-range change amount by another means without using the measurement result of the carrier phase of the satellite signal under the situation where the moving body is stopped. It is an object of the present invention to provide a mobile body positioning device that enables a ring.
- a mobile body positioning apparatus includes a pseudo distance calculation means for calculating a pseudo distance between a satellite and a mobile body based on a received satellite signal, Stop determination means for determining whether or not the body has stopped;
- Satellite position calculating means for calculating the position of the satellite from which the satellite signal is transmitted; pseudo distance change estimating means for estimating the pseudo distance change;
- a positioning means for positioning the position of the moving body based on the pseudo distance calculated by the pseudo distance calculating means and the pseudo distance change estimated by the pseudo distance change estimating means;
- the pseudo-range change amount estimation means uses the satellite position change history calculated by the satellite position calculation means when the stop determination means determines that the moving body is stopped.
- a second invention is the mobile body positioning apparatus according to the first invention
- the pseudo distance change amount estimating means estimates the pseudo distance change amount using a movement vector of the moving body when the stop determining means determines that the moving body is not stopped. To do.
- a third invention is the mobile body positioning apparatus according to the second invention.
- a fourth invention is the mobile body positioning apparatus according to the third invention.
- the pseudo-range change amount estimating means calculates a relative movement vector of the satellite with reference to the moving body by using the moving tuttle of the moving body and the movement vector of the satellite, and the satellite position calculating means Using the calculated position of the satellite and the position of the moving body measured by the positioning means, the position vector of the satellite with respect to the moving body is calculated, and the inner product of the calculated relative movement vector and the position vector is calculated as a pseudorange. It is characterized by being estimated as the amount of change.
- a fifth invention is the mobile body positioning apparatus according to any one of the second to fourth inventions, wherein the movement vector of the mobile body is detected by a sensor mounted on the mobile body. It is calculated based on information related to the amount of movement and the amount of change in the Doppler frequency of the carrier wave of the satellite signal.
- a sixth invention is the mobile body positioning apparatus according to any one of the first to fifth inventions, wherein the pseudo-range change amount estimating means determines that the moving body is stopped by the stop determining means.
- the satellite movement vector derived based on the satellite position change history calculated by the satellite position calculation means, the satellite position calculated by the satellite position calculation means, and the movement measured by the positioning means It is characterized in that the inner product of the position vector of the satellite with respect to the moving body derived based on the position of the body is estimated as the pseudo-range change amount.
- a seventh invention is the mobile body positioning device according to any one of the first to sixth inventions, wherein the pseudo distance calculation is performed using the pseudo distance change amount estimated by the pseudo distance change amount estimation means.
- Filter means for filtering the pseudorange calculated by the means are the pseudo distance change amount estimated by the pseudo distance change amount estimation means.
- the positioning means measures the position of the moving body based on the pseudo distance filtered by the filter means.
- the pseudo-range change amount is estimated by another means without using the measurement result of the carrier wave phase of the satellite signal under the situation where the moving body stops and becomes V.
- a mobile body positioning device capable of filtering can be obtained.
- FIG. 1 is a system configuration diagram showing an overall configuration of GPS to which a mobile body positioning device according to the present invention is applied.
- FIG. 2 is a schematic system configuration diagram showing an embodiment of a GPS receiver 1 mounted on the vehicle 90 in FIG.
- FIG. 3 is a diagram showing the relationship between the world coordinate system and the local coordinate system.
- FIG. 4 is a flowchart showing a main part of a pseudo distance change amount estimation process by a pseudo distance change amount estimation unit 50A according to the first embodiment.
- FIG. 5 is a schematic system configuration diagram showing the main configuration of a GPS receiver 2 according to a second embodiment.
- FIG. 6 is a flowchart showing a main part of pseudo distance change amount estimation processing by a pseudo distance change amount estimation unit 50A according to the second embodiment.
- FIG. 7 is a schematic system configuration diagram showing the main configuration of a GPS receiver 3 according to Example 3.
- FIG. 8 is a flowchart showing a main part of an example of pseudo distance change amount estimation processing by a pseudo distance change amount estimation unit 50C according to the third embodiment.
- FIG. 1 is a system configuration diagram showing an overall configuration of a GPS (Global Positioning System) to which a mobile body positioning device according to the present invention is applied.
- GPS Global Positioning System
- the vehicle 90 is merely an example of a moving body, and other moving bodies include information terminals such as motorcycles, railways, ships, airplanes, hawk lifts, robots, and mobile phones that move as people move. And so on.
- the GPS satellite 10 constantly broadcasts navigation messages (satellite signals) toward the earth.
- the navigation message includes satellite orbit information (F-Merith and Almanac) for the corresponding GPS satellite 10, clock correction values, and ionospheric correction factors.
- the navigation message is spread by the C / A code and carried on the L1 wave (frequency: 1575.42 MHz), and is constantly broadcast to the earth.
- the L1 wave is a combined wave of a sine wave modulated with a C / A code and a Cos wave modulated with a P code (Precision Code), and is orthogonally modulated.
- the C / A code and the P code are pseudo noise codes, which are code strings in which 1 and 1 are arranged irregularly and periodically.
- GPS satellites 10 orbit the earth at an altitude of about 20, OOOKm, and each of the four GPS satellites 10 is evenly distributed on six orbiting earth orbits inclined by 55 degrees. It is arranged. Therefore, as long as the sky is open, at least 5 GPS satellites 10 can be observed at any time on the earth.
- the vehicle 90 is equipped with a GPS receiver 1 as a mobile body positioning device.
- the GPS receiver 1 measures the position of the vehicle 90 based on the satellite signal from the GPS satellite 10 as described in detail below.
- FIG. 2 is a schematic system configuration diagram showing an embodiment of the GPS receiver 1 mounted on the vehicle 90 of FIG. Figure 2 shows only one GPS satellite 10 (the subscript is the satellite number) to avoid complexity.
- the signal processing related to GPS satellite 10 power and other satellite signals will be explained as a representative.
- the signal processing related to the satellite signal of the GPS satellite 10 power is the same as the signal processing related to the satellite signal from other GPS satellites 10 and 10 etc. It is substantially the same.
- the GPS receiver 1 of the present embodiment includes, as main functional units, a receiving unit 20A, a filter 30, a positioning calculation unit 40, a pseudo-range change amount estimating unit 50A, a satellite position calculating unit. 60 and a stop determination unit 70 are provided.
- the receiving unit 20A receives a satellite signal from which 10 GPS satellites are transmitted via the GPS antenna 22, and performs C / A code synchronization using a replica C / A code generated internally.
- the navigation message is extracted, and the pseudo distance p between the GPS satellite 10 and the vehicle 90 (more precisely, the GPS receiver 1) is calculated.
- the pseudorange p is different from the true distance between the GPS satellite 10 and the vehicle 90, and includes errors due to clock error (clock bias) and changes in radio wave propagation speed.
- the method of C / A code synchronization can vary widely, and any appropriate method may be employed. For example, DDL (Delay— Locked
- Loop may be used to track the code phase at which the correlation value of the replica C / A code with respect to the received C / A code becomes a peak.
- “′” added to the pseudo distance p indicates that a filter process described later is executed! /,! /.
- the pseudo distance p relative to the GPS satellite 10, may be calculated as follows, for example.
- N corresponds to the number of bits of the C / A code between the GPS satellite 10 and the vehicle 90, and is calculated based on the phase of the replication C / A code and the receiver clock inside the GPS receiver 1.
- the number 300 is derived from the fact that the length of 1 bit of C / A coding power is 13 and the length corresponding to 1 bit is about 300 m (l ⁇ s X speed of light).
- a signal representing the pseudo distance P ′ calculated in this way is input to the filter 30.
- the pseudo-range change amount estimation unit 50A estimates the pseudo-range change amount ⁇ p (corresponding to the relative movement amount of the GPS satellite 10 with respect to the vehicle 90 during the observation period) during the observation period. Details of the estimation method will be described later.
- the filter processing of the pseudorange ⁇ ′ is executed.
- the pseudo distance ⁇ after filtering is derived according to the following arithmetic expression. [0027] [Equation 1]
- (i) represents the current value
- (i 1) represents the previous value
- M is a weighting factor.
- the value of M is appropriately determined in consideration of accuracy and responsiveness.
- the term of time integration of ⁇ corresponds to the pseudorange change amount in the observation period, and the pseudorange change amount ⁇ estimated by the pseudorange change amount estimation unit 50 ⁇ is substituted as described above.
- the filtering (smoothing) in the filter 30 can also be realized using a filter other than the above-described hatch filter, for example, a Kalman filter.
- a signal representing the pseudorange ⁇ after filtering is input to the positioning calculation unit 40.
- the satellite position calculation unit 60 calculates the current position (X, ⁇ , ⁇ ) of the GPS satellite 10 in the world coordinate system based on the satellite orbit information of the navigation message and the current time. Since the GPS satellite 10 is one of artificial satellites, its movement is limited to a certain plane (orbital plane) including the center of gravity of the earth. The orbit of the GPS satellite 10 is an elliptical motion with the center of gravity of the earth as one focal point, and the position of the GPS satellite 10 on the orbital plane can be calculated by sequentially calculating the Kepler equation.
- the position of the GPS satellite 10 (X, ⁇ , ⁇ ) is determined based on the rotational relationship between the orbital plane of the GPS satellite 10 and the equatorial plane of the world coordinate system. It can be obtained by converting the position into a three-dimensional rotational coordinate. As shown in Fig. 3, the field coordinate system is defined by the X axis and the X axis that are orthogonal to each other in the equator plane, and the X axis that is orthogonal to both axes with the center of gravity of the earth as the origin. Signals representing the satellite positions (X, ⁇ , ⁇ ) are input to the positioning calculation unit 40 and the pseudo-range change estimation unit 50 ⁇ .
- the positioning calculation unit 40 measures the position (X, ⁇ , ⁇ ) of the vehicle 90 based on the calculation result of the satellite position and the calculation result of the pseudo distance ⁇ supplied from the filter 30.
- Positioning calculation cycle May be, for example, an observation period (eg, lms) or a predetermined number of observation periods (eg, 50 ms or 100 ms).
- the positioning result is supplied to the pseudo distance change amount estimation unit 50A and also supplied to, for example, a navigation system.
- the position of the vehicle 90 may be derived on the principle of triangulation using the respective pseudoranges p and satellite positions obtained for the three GPS satellites 10.
- the positioning method of the position of the vehicle 90 is not limited to the single positioning as described above, but may be interference positioning (a method in which received data at a fixed station installed at a known point is used in combination). In the case of interference positioning, the position of the vehicle 90 is measured using the single phase difference or double phase difference of the pseudo distance p obtained by the fixed station and the vehicle 90 as described above.
- the stop determination unit 70 determines whether or not the vehicle 90 is stopped based on the output signal of the wheel speed sensor. Specifically, the stop determination unit 70 determines that the vehicle 90 stops and is! / When the index value based on the output value (vehicle speed) of the wheel speed sensor falls below a predetermined threshold.
- the index value may be, for example, a vehicle speed, or may be a value obtained by integrating the vehicle speed over time.
- the predetermined threshold may be experimentally adapted according to the characteristics of the index values when the vehicle is stopped and when moving.
- the wheel speed sensor may be mounted on each wheel of the vehicle 90 and output a vehicle speed panel according to the rotational speed of the wheel.
- the stop determination unit 70 may make the determination based on the output signals from all the wheel speed sensors, or may make the determination based on the output signals from any of the wheel speed sensors.
- the stop determination unit 70 uses other in-vehicle sensors that can output a physical quantity related to the vehicle speed, such as a sensor that measures the rotation speed of the output shaft of the transmission instead of or in addition to the wheel speed sensor. Thus, it may be determined whether or not the vehicle 90 is stopped.
- the stop determination unit 70 may determine whether or not the vehicle 90 is stopped based on the positioning result that can be acquired from the positioning calculation unit 40. Specifically, the stop determination unit 70 determines that the vehicle 90 is stopped when the index value based on the position information of the vehicle 90 falls below a predetermined threshold.
- the index value may be, for example, a time change of the vehicle position (that is, the speed of the vehicle 90) based on the positioning result of the positioning calculation unit 40, or may be a value obtained by integrating the time.
- the predetermined threshold depends on the characteristics of the index value when the vehicle is stopped and moving. It may be adapted experimentally accordingly.
- the stop determination unit 70 may determine whether or not the vehicle 90 is stopped based on output signals from the acceleration sensor and the parallel sensor. Specifically, the stop determination unit 70 time-differentiates each output value of the acceleration sensor and the parallel sensor, and when the respective differential value falls below a threshold value set for each, the vehicle 90 is Judge that it is stopped.
- the acceleration sensor and the single rate sensor preferably detect acceleration along three axes that are orthogonal to each other and a high rate around the three axes.
- the differential values (index values) of the six types of output values are individually compared with the threshold values set for each.
- the stop determination unit 70 determines that the vehicle 90 is stopped when all the differential values of the six types of output values are below the respective threshold values set for each.
- Each threshold value may be experimentally adapted according to the difference in characteristics of each index value (differential value) when the vehicle is stopped and when the vehicle is moving.
- the stop determination unit 70 determines whether or not the vehicle 90 is stopped! /, Using the determination results of all or any two combinations of the above three types of determination methods as AND conditions. It's okay.
- the determination result by the stop determination unit 70 is supplied to the pseudo distance change amount estimation unit 50A.
- the determination result by the stop determination unit 70 may be expressed by a stop / movement flag. Specifically, when the stop determination unit 70 determines that the vehicle 90 is stopped, for example, a stop / movement flag is set. On the other hand, if it is determined that the vehicle 90 has not stopped, the stop / movement flag is cleared. The state of the stop / movement flag is referred to by the pseudo distance change amount estimation unit 50A.
- FIG. 4 is a flowchart showing a main part of an example of the pseudo distance change estimation process performed by the pseudo distance change estimation unit 50A.
- the processing routine shown in FIG. 4 may be repeatedly executed every predetermined cycle (for example, every positioning calculation cycle of the positioning calculation unit 40).
- step 100 the pseudo distance change amount estimation unit 50A acquires the determination result by the stop determination unit 70.
- the pseudo-range variation estimating unit 50A receives the guard from the satellite position calculating unit 60. Based on the star position information, the movement vector of GPS satellite 1 ( ⁇ is calculated, and based on the satellite position information from the satellite position calculation unit 60 and the position information of the vehicle 90 from the positioning calculation unit 40, the vehicle 90 Calculates the position vector of GPS satellite 10 based on the position (hereinafter referred to as “line of sight line”), specifically, the movement vector of GPS satellite 10 is the position of GPS satellite 10 obtained in this cycle.
- line of sight line the position of GPS satellite 10 obtained in this cycle.
- the line-of-sight vector can be derived from the position (X i Y i), Z (i)) of the GPS satellite lC ⁇ obtained in the current cycle, and the position of the vehicle 90 (X It may be derived by subtracting (i-1), Y (i-1), Z (i-1)), and the movement vector may be calculated by the satellite position calculation unit 60.
- the processing order of steps 100 and 110 may be reversed.
- step 120 the pseudo distance change amount estimation unit 50A determines the determination result by the stop determination unit 70.
- step 140 the process proceeds to step 130.
- step 130 the pseudo distance change amount estimation unit 50A does not estimate the pseudo distance change amount ⁇ p.
- the stop determination unit 70 determines that the vehicle 90 is not stopped
- the pseudo distance change amount ⁇ p is not estimated by the pseudo distance change amount estimation unit 50A.
- the function of the filter 30 described above is substantially stopped. That is, the positioning calculation unit 40 performs positioning by directly using the pseudo distance P ′ from the receiving unit 20A.
- the pseudo-range change estimation unit 50A estimates the pseudo-range change ⁇ p using the movement vector and the line-of-sight vector of the GPS satellite 10 obtained from step 110 described above.
- pseudorange change amount delta P may be derived by the inner product of the movement vector and the viewing vector.
- the line-of-sight vector uses the position of the vehicle 90 obtained in the previous cycle as described above. However, when the vehicle 90 is stopped, the position of the vehicle 90 that should be obtained in the current cycle is obtained in the previous cycle. This is not inconvenient because it can be considered to be the same as the position of the vehicle 90 to be mounted.
- the pseudo distance change amount estimation unit 50 ⁇ can be obtained by subtracting the magnitude L (i) of the line-of-sight vector in the current cycle and the magnitude L (i 1) of the line-of-sight vector in the previous cycle.
- the magnitude L (i) of the line-of-sight vector in the current cycle is obtained by using the position of the GPS satellite 10 (X (i), Y ( i), Z (i)), the size of the vector obtained by subtracting the position (X (i-1), Y (i-1), Z (i--1)) of the vehicle 90 obtained in the previous cycle May be derived.
- the magnitude L (i 1) of the line-of-sight vector in the previous cycle is the position of the GPS satellite 10 obtained in the previous cycle (X (i-1), Y (i-l), Z (i-l )) Is derived by subtracting the position (X (i- 1), Y (i- 1), Z (i 1)) of the vehicle 90 obtained in the previous cycle.
- the pseudo-range change ⁇ p estimated in this way is input to the filter 30 as described above and used for smoothing the pseudo-range p ′.
- the second embodiment is different from the first embodiment in that the pseudo-range change amount ⁇ p is estimated in different estimation modes when the vehicle 90 is in a moving state and when it is in a stopped state. Different.
- the configuration peculiar to the second embodiment will be described mainly. Other configurations may be the same as those in the first embodiment.
- FIG. 5 is a schematic system configuration diagram showing the main configuration of the GPS receiver 2 according to the second embodiment.
- the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
- the signal processing related to the satellite signal of 10 GPS satellites will be described as a representative.
- the receiving unit 20B transmits a satellite signal from which GPS satellite 10 power is transmitted via the GPS antenna 22.
- the C / A code is synchronized using the replica C / A code generated internally, and the navigation message is taken out, and between the GPS satellite 10 and the vehicle 90 (precisely the GPS receiver 2).
- the receiving unit 20B has a function of measuring the carrier wave phase of the satellite signal, and has a function of measuring the Doppler frequency change amount ⁇ f of the Doppler-shifted received carrier wave using a replica carrier generated inside.
- the Doppler frequency variation A f is the replica carrier frequency fr and the known carrier frequency f (1575.42M
- This function is a PLL (Phase—Locked) that uses a replica carrier to calculate the carrier correlation value and track the received carrier.
- a signal representing the Doppler frequency change amount A f is input to the pseudo-range change amount estimation unit 50B.
- FIG. 6 is a flowchart illustrating a main part of an example of the pseudo distance variation estimation process by the pseudo distance variation estimation unit 50B according to the second embodiment.
- the processing routine shown in FIG. 6 may be repeatedly executed every predetermined period (for example, every positioning calculation period).
- predetermined period for example, every positioning calculation period.
- the same processes as those shown in FIG. 4 according to the first embodiment are denoted by the same step numbers and the description thereof is omitted.
- the pseudo distance change amount estimating unit 50B estimates the pseudo distance change amount ⁇ p based on the Doppler frequency change amount A f obtained from the receiving unit 20B. For example, the relative speed ⁇ between the GPS satellite 10 and the vehicle 90 is calculated based on the Doppler frequency change amount A f using, for example, the following relational expression.
- a f AV-f / (c AV)
- the pseudo-range change ⁇ is derived by time-integrating the relative speed ⁇ .
- the integration period may correspond to the period of the processing routine.
- the pseudo-range variation ⁇ estimated in this way is input to the filter 30 as described above, and is substituted into the term of the time integration of ⁇ in the above-described equation 1, thereby smoothing the pseudo-range ⁇ ′ (so-called Used for carrier smoothing.
- the vehicle 90 When the vehicle 90 is stopped, it is based on the satellite position information in the same manner as in the first embodiment.
- the pseudo-range change ⁇ p is estimated and the pseudo-range change ⁇ p is estimated using the Doppler frequency change A f when the vehicle 90 is moving.
- the pseudo distance P ′ can be smoothed. As a result, the accuracy of the pseudo distance p and the accuracy of the position of the vehicle 90 can be improved in both the moving / stopping state of the vehicle 90.
- the pseudorange change ⁇ p can be accurately estimated when the satellite position information is used.
- the pseudo distance change amount ⁇ p is accurately changed according to the state of the vehicle 90 by switching the estimation method of the pseudo distance change amount ⁇ p between the stopped state and the moving state of the vehicle 90. As a result, it is possible to improve the accuracy of the pseudorange P, and hence the accuracy of the position of the vehicle 90.
- the relative velocity ⁇ between the GPS satellite 10 and the vehicle 90 may be calculated by the filter 30 and introduced into the filter equation shown in Equation 1.
- the third embodiment is different from the first embodiment in that the pseudo-range change amount ⁇ is estimated in different estimation modes when the vehicle 90 is in a moving state and when it is in a stopped state. Different.
- the configuration peculiar to the third embodiment will be described mainly. Other configurations may be the same as those in the first embodiment.
- FIG. 7 is a schematic system configuration diagram showing the main configuration of the GPS receiver 3 according to the third embodiment.
- the same reference numerals are used for the same configurations as in the first embodiment. The description is omitted.
- the signal processing related to the satellite signal from the GPS satellite lC ⁇ will be described as a representative.
- the external sensor 80 is connected to the GPS receiver 3.
- the external sensor 80 may be incorporated in the force GPS receiver 3 which is a sensor provided outside the GPS receiver 3.
- the external sensor 80 is a sensor that acquires information (hereinafter referred to as “vehicle information”) related to the movement amount and direction (azimuth) of the vehicle 90, and may be a combination of a plurality of types of sensors.
- vehicle information information
- the external sensor 80 may be a combination of a magnetic impedance sensor (geomagnetic sensor) that detects the direction of the vehicle 90 and an acceleration sensor that detects the acceleration of the vehicle 90.
- the external sensor 80 may be a combination (that is, an INS sensor) of an acceleration sensor and a parallel sensor (gyro sensor) that detects the speed (angular speed) of the vehicle 90 in the single direction.
- the vehicle information from the external sensor 80 is input to the pseudo distance change amount estimation unit 50C at every predetermined period.
- FIG. 8 is a flowchart illustrating a main part of an example of the pseudo distance variation estimation process by the pseudo distance variation estimation unit 50C according to the third embodiment.
- the processing routine shown in FIG. 8 may be repeatedly executed every predetermined period (for example, every positioning calculation period).
- predetermined period for example, every positioning calculation period.
- the pseudo distance change amount estimation unit 50C calculates the movement vector of the vehicle 90 (more precisely, the GPS receiver 3) based on the vehicle information from the external sensor 80.
- the movement vector is a movement vector between the previous cycle and the current cycle.
- the direction of the movement vector is derived based on the direction of the vehicle 90 (for example, information from the geomagnetic sensor), and the amount of movement of the vehicle 90 (the magnitude of the movement vector) is calculated based on the acceleration signal ( It may be derived by integrating twice after filtering).
- the movement vector may be calculated on the external sensor 80 side and acquired by the pseudo distance change amount estimation unit 50C.
- the pseudo-range variation estimation unit 50C calculates the movement vector of the GPS satellite 10 based on the satellite position information from the satellite position calculation unit 60 and the satellite from the satellite position calculation unit 60. Based on the position information and the position information of the vehicle 90 from the positioning calculation unit 40 And the line-of-sight vector is calculated.
- the movement vector of GPS satellite 1 ( ⁇ is the GPS vector obtained in the previous cycle from the position (X (i), Y (i), Z (i)) of GPS satellite 10 obtained in this cycle. It may be derived by subtracting the position of satellite 10 (X (i-1), Y (i-1), Z (i-1)), and the line-of-sight vector is the GPS satellite lC obtained in this cycle. From the position of ⁇ (X i Y (i), Z (i)), the estimated position of the vehicle 90 in this cycle (X (i), Y (i), Z (i))
- Vehicle 90 position (X (i-1), Y (i-l), Z (i--1)) or similar estimated position (X (i-1), Y (i-1)) , Z (i 1)) and estimate from previous cycle to current cycle Estimate Estimate
- It may be estimated based on the movement vector of the vehicle 90 at (the calculation result of step 113 above).
- the movement vector of the GPS satellite 10 may be calculated by the satellite position calculation unit 60. Further, the processing order of steps 100, 113, and 115 may be arbitrary.
- the pseudo distance change estimation unit 50C estimates the pseudo distance change ⁇ based on the vehicle information from the external sensor 80 and the satellite position information from the satellite position calculation unit 60. Specifically, the pseudo distance change amount estimation unit 50C uses the movement vector of the vehicle 90 obtained in step 113 above, and the movement vector and line-of-sight vector of the GPS satellite 10 obtained from step 115 above. Then, the pseudo-range change amount ⁇ is estimated. In this case, the movement vector of the vehicle 90 and the movement vector of the GPS satellite 10 are used to obtain the relative movement vector of the GPS satellite 10 with respect to the vehicle 90, and the inner product of the relative movement vector and the line-of-sight vector is changed by the pseudorange change. The quantity ⁇ may be calculated.
- (i) —L (i ⁇ 1)) may be estimated as the pseudorange change ⁇ p.
- the magnitude L (i) of the line-of-sight vector in this cycle is calculated from the position (X (i), Y (i), Z (i)) of the GPS satellite 10 obtained in this cycle.
- the size of the vector obtained by subtracting the estimated position (X (i), Y (i), Z (i)) of the vehicle 90 is estimated Estimated Estimated
- the magnitude L (i 1) of the line-of-sight vector in the previous cycle is the position of the GPS satellite 10 obtained in the previous cycle (X (i-1), Y (i-l), Z (i-l) ) From the estimated position of vehicle 90 in the previous cycle (X (i-1), Y (i-1), Z (i-l)) u estimation u estimation U estimation May be derived by obtaining the magnitude of the vector obtained by subtracting.
- the pseudo-range variation ⁇ p estimated in this way is input to the filter 30 as described above, and is used for smoothing the pseudo-range ⁇ , by substituting it into the time integral term of ⁇ in Equation 1 above. Is done.
- the stopped state of the [0059] vehicle 90 in the same manner as in Example 1 above, estimates the pseudorange change amount delta P and based on the satellite position information, the moving state of the vehicle 90, from the external sensor 80 Since the pseudo distance change amount ⁇ is estimated using vehicle information or the like, the pseudo distance ⁇ ′ can be smoothed in any of the movement / stop states of the vehicle 90.
- the accuracy of the pseudo distance ⁇ and the accuracy of the position of the vehicle 90 can be improved in both the moving / stopping state of the vehicle 90.
- the pseudo distance change ⁇ in the moving state of the vehicle 90 as described above is estimated based on vehicle information from the external sensor 80, etc., when carrying out the carrier smoothing of the pseudo distance ⁇ '. It is not necessary to derive the amount of change in Doppler frequency necessary for. Therefore, even when the inexpensive GPS receiver 3 that saves the function of measuring the carrier wave phase of the satellite signal is used, the pseudorange ⁇ can be smoothed in the moving state of the vehicle 90.
- the pseudo-range change can be accurately changed according to the state of the vehicle 90 by switching the estimation method of the pseudo-range change amount ⁇ between the stopped state and the moving state of the vehicle 90.
- the force for deriving the pseudorange ⁇ using the C / A code is based on the L1 wave ⁇ code and / or the L2 wave ⁇ code.
- the present invention can be applied to a configuration for calculating the pseudorange ⁇ ′ for the GPS satellite 10.
- the P code may be extracted by a DLL using the cross correlation method. Pseudorange p, based on P code,
- the power of the present invention applied to GPS is shown.
- the present invention is applied to satellite systems other than GPS, for example, other GNSS (Global Navigation Satellite System) such as Galileo. Applicable.
- GNSS Global Navigation Satellite System
- Galileo Galileo Applicable.
- the mobile body positioning device is realized by the GPS receivers 1, 2, 3; however, the mobile body positioning device is connected to the GPS receivers 1, 2, 3, and the GPS receivers 1, 2, 3 It may be realized in cooperation with other electronic components.
- the above-described second and third embodiments can be appropriately combined depending on the situation.
- the vehicle 90 when the vehicle 90 is in a moving state, when the ionospheric activity is active (a refraction error is likely to increase! /), Or when the vehicle 90 is present in an urban area (such as blocking radio waves or reflected waves)
- the pseudo distance change ⁇ p is estimated by the processing of step 160 in the above-described third embodiment.
- the pseudo-range change ⁇ p may be estimated by the process of step 150 in the second embodiment.
- the movement amount (the magnitude of the movement vector) of the vehicle 90 is a parameter that represents the vehicle speed, such as an output signal of the wheel speed sensor, instead of the acceleration from the acceleration sensor.
Abstract
Mobile position positioning devices (1, 2, 3) comprise means (20A, 20B) for calculating pseudo range ρ' between a satellite (10) and a vehicle (90), a stop judgment means (70) for judging whether a mobile has stopped or not, a satellite position calculation means (60) for calculating the position of the satellite, means (50A, 50B, 50C) for estimating a pseudo range variation Δρ, and a means (40) for positioning the mobile position based on the pseudo range and the pseudo range variation, wherein the means for estimating the pseudo range variation estimates the pseudo range variation using a variation record of the satellite position calculated by the satellite position calculation means when stoppage of the mobile is judged by the stop judgment means.
Description
明 細 書 Specification
移動体位置測位装置 Mobile positioning device
技術分野 Technical field
[0001] 本発明は、衛星信号に基づ V、て移動体の位置を測位する移動体位置測位装置に 関する。 TECHNICAL FIELD [0001] The present invention relates to a moving body position positioning device that measures the position of a moving body based on satellite signals.
背景技術 Background art
[0002] 従来から、この種の移動体位置測位装置にお!/、て、 GPS衛星信号に含まれる PN コードに基づいて GPS衛星信号からの擬似距離を算出する手段と、 GPS衛星信号 力、らの衛星信号の搬送波のドップラー成分を所定時点から積算することで当該時点 からの擬似距離の変化量を算出する手段とを備え、それぞれ算出した擬似距離と擬 似距離変化量との差分を求め、当該差分にフィルタをかけることで擬似距離の高周 波揺らぎを取り除く技術が知られている(例えば、特許文献 1参照)。この種のフィルタ リングは、いわゆるキャリアスムージングとして知られている。 [0002] Conventionally, in this type of mobile positioning device, a means for calculating a pseudorange from a GPS satellite signal based on a PN code included in the GPS satellite signal, a GPS satellite signal power, And a means for calculating the amount of change in pseudorange from that point by accumulating the Doppler component of the satellite signal carrier from a predetermined point in time, and calculating the difference between the calculated pseudorange and the amount of change in pseudorange. A technique is known that removes high-frequency fluctuations in the pseudorange by filtering the difference (see, for example, Patent Document 1). This type of filtering is known as so-called carrier smoothing.
特許文献 1 :特開平 7— 198821号公報 Patent Document 1: JP-A-7-198821
発明の開示 Disclosure of the invention
発明が解決しょうとする課題 Problems to be solved by the invention
[0003] しかしながら、安価な GNSS(Global [0003] However, inexpensive GNSS (Global
Navigation Satellite System)受信機では、衛星信号の搬送波位相を測定する機能を 省いているため、 GPS衛星信号からの衛星信号の搬送波のドップラー成分から、フィ ルタリング (スム一ジング)に用いる擬似距離変化量を算出することができない。従つ て、力、かる安価な GNSS受信機において、別の手段により擬似距離変化量を算出し て、擬似距離のフィルタリングを行うことができれば、測位精度を高めることができるの で、有用である。また、衛星信号の搬送波位相を測定する機能を備える GNSS受信 機においても、移動体に搭載される場合には周囲環境等に依存してドップラー成分 の測定精度が悪化する場合があるので、衛星信号の搬送波位相の計測結果以外の 別の手段により擬似距離変化量を算出して、擬似距離のフィルタリングを可能にして おくことは有用である。
[0004] また、特に移動体が停止して!/、る状態では、移動体が停止して!/、ることを利用する ことで、衛星信号の搬送波位相の計測結果から擬似距離変化量を算出するよりも、 誤差の少ない態様で、擬似距離変化量を算出することが可能である(これにより、ひNavigation Satellite System) receiver eliminates the function of measuring the carrier phase of the satellite signal, so the pseudo-range variation used for filtering (smoothing) from the Doppler component of the satellite signal carrier from the GPS satellite signal Cannot be calculated. Therefore, if the GNSS receiver, which is powerful and inexpensive, can calculate the pseudorange change by another means and perform pseudorange filtering, the positioning accuracy can be improved, which is useful. . Also, GNSS receivers equipped with a function to measure the carrier wave phase of satellite signals may degrade the Doppler component measurement accuracy depending on the surrounding environment when mounted on a mobile object. It is useful to enable pseudorange filtering by calculating the pseudorange change by other means other than the measurement result of the carrier phase. [0004] In particular, when the moving body is stopped! /, It is possible to use the fact that the moving body stops! /, To obtain the pseudorange change amount from the measurement result of the carrier wave phase of the satellite signal. It is possible to calculate the pseudo-range change amount with less error than to calculate (this makes it possible to calculate
V、ては擬似距離及び測位結果の精度が向上する)。 V, and the accuracy of pseudorange and positioning results will improve).
[0005] そこで、本発明は、移動体が停止している状況下で、衛星信号の搬送波位相の計 測結果を用いずに別の手段により擬似距離変化量を推定して、擬似距離のフィルタ リングを可能とする移動体位置測位装置の提供を目的とする。 [0005] Therefore, the present invention provides a pseudo-range filter by estimating the pseudo-range change amount by another means without using the measurement result of the carrier phase of the satellite signal under the situation where the moving body is stopped. It is an object of the present invention to provide a mobile body positioning device that enables a ring.
課題を解決するための手段 Means for solving the problem
[0006] 上記目的を達成するため、第 1の発明に係る移動体位置測位装置は、受信した衛 星信号に基づいて衛星と移動体の間の擬似距離を算出する擬似距離算出手段と、 移動体が停止したか否かを判定する停止判定手段と、 [0006] In order to achieve the above object, a mobile body positioning apparatus according to a first aspect of the present invention includes a pseudo distance calculation means for calculating a pseudo distance between a satellite and a mobile body based on a received satellite signal, Stop determination means for determining whether or not the body has stopped;
前記衛星信号の発信元の衛星の位置を算出する衛星位置算出手段と、 擬似距離変化量を推定する擬似距離変化量推定手段と、 Satellite position calculating means for calculating the position of the satellite from which the satellite signal is transmitted; pseudo distance change estimating means for estimating the pseudo distance change;
前記擬似距離算出手段により算出された擬似距離と、前記擬似距離変化量推定 手段により推定された擬似距離変化量とに基づ V、て、移動体の位置を測位する測位 手段とを備え、 A positioning means for positioning the position of the moving body based on the pseudo distance calculated by the pseudo distance calculating means and the pseudo distance change estimated by the pseudo distance change estimating means;
前記擬似距離変化量推定手段は、前記停止判定手段により移動体の停止が判定 された場合に、前記衛星位置算出手段により算出される衛星の位置の変化履歴を用 The pseudo-range change amount estimation means uses the satellite position change history calculated by the satellite position calculation means when the stop determination means determines that the moving body is stopped.
V、て、前記擬似距離変化量を推定することを特徴とする。 V, and the pseudo distance change amount is estimated.
[0007] 第 2の発明は、第 1の発明に係る移動体位置測位装置において、 [0007] A second invention is the mobile body positioning apparatus according to the first invention,
前記擬似距離変化量推定手段は、前記停止判定手段により移動体が停止してい ないと判定された場合に、前記移動体の移動ベクトルを用いて、前記擬似距離変化 量を推定することを特徴とする。 The pseudo distance change amount estimating means estimates the pseudo distance change amount using a movement vector of the moving body when the stop determining means determines that the moving body is not stopped. To do.
[0008] 第 3の発明は、第 2の発明に係る移動体位置測位装置において、 [0008] A third invention is the mobile body positioning apparatus according to the second invention,
前記擬似距離変化量推定手段は、前記停止判定手段により移動体が停止してい ないと判定された場合に、前記移動体の移動ベクトルと、前記衛星位置算出手段に より算出される衛星の位置の変化履歴に基づいて導出される衛星の移動ベクトルと を用いて、前記擬似距離変化量を推定することを特徴とする。
[0009] 第 4の発明は、第 3の発明に係る移動体位置測位装置において、 The pseudo-distance change amount estimating means determines the movement vector of the moving object and the position of the satellite calculated by the satellite position calculating means when the stop determining means determines that the moving object is not stopped. The pseudo-range change amount is estimated using a satellite movement vector derived based on the change history. [0009] A fourth invention is the mobile body positioning apparatus according to the third invention,
前記擬似距離変化量推定手段は、前記移動体の移動 タトルと、前記衛星の移動 ベクトルとを用いて、移動体を基準とした前記衛星の相対移動ベクトルを算出すると 共に、前記衛星位置算出手段により算出される衛星の位置と、前記測位手段により 測位される移動体の位置とを用いて、移動体に対する衛星の位置ベクトルを算出し、 該算出した相対移動ベクトルと位置ベクトルとの内積を擬似距離変化量として推定す ることを特徴とする。 The pseudo-range change amount estimating means calculates a relative movement vector of the satellite with reference to the moving body by using the moving tuttle of the moving body and the movement vector of the satellite, and the satellite position calculating means Using the calculated position of the satellite and the position of the moving body measured by the positioning means, the position vector of the satellite with respect to the moving body is calculated, and the inner product of the calculated relative movement vector and the position vector is calculated as a pseudorange. It is characterized by being estimated as the amount of change.
[0010] 第 5の発明は、第 2〜4のいずれかの発明に係る移動体位置測位装置において、 前記移動体の移動ベクトルは、移動体に搭載されたセンサにより検出される移動体 の姿勢と移動量に関連する情報、又は、衛星信号の搬送波のドップラー周波数変化 量に基づいて算出されることを特徴とする。 [0010] A fifth invention is the mobile body positioning apparatus according to any one of the second to fourth inventions, wherein the movement vector of the mobile body is detected by a sensor mounted on the mobile body. It is calculated based on information related to the amount of movement and the amount of change in the Doppler frequency of the carrier wave of the satellite signal.
[0011] 第 6の発明は、第 1〜5のいずれかの発明に係る移動体位置測位装置において、 前記擬似距離変化量推定手段は、前記停止判定手段により移動体の停止が判定 された場合に、前記衛星位置算出手段により算出される衛星の位置の変化履歴に 基づいて導出される衛星の移動ベクトルと、前記衛星位置算出手段により算出される 衛星の位置及び前記測位手段により測位される移動体の位置に基づいて導出され る移動体に対する衛星の位置ベクトルとの内積を、前記擬似距離変化量として推定 することを特徴とする。 [0011] A sixth invention is the mobile body positioning apparatus according to any one of the first to fifth inventions, wherein the pseudo-range change amount estimating means determines that the moving body is stopped by the stop determining means. In addition, the satellite movement vector derived based on the satellite position change history calculated by the satellite position calculation means, the satellite position calculated by the satellite position calculation means, and the movement measured by the positioning means. It is characterized in that the inner product of the position vector of the satellite with respect to the moving body derived based on the position of the body is estimated as the pseudo-range change amount.
[0012] 第 7の発明は、第 1〜6のいずれかの発明に係る移動体位置測位装置において、 前記擬似距離変化量推定手段により推定された擬似距離変化量を用いて、前記 擬似距離算出手段により算出された擬似距離にフィルタをかけるフィルタ手段を更に 備え、 [0012] A seventh invention is the mobile body positioning device according to any one of the first to sixth inventions, wherein the pseudo distance calculation is performed using the pseudo distance change amount estimated by the pseudo distance change amount estimation means. Filter means for filtering the pseudorange calculated by the means,
前記測位手段は、前記フィルタ手段によりフィルタがかけられた擬似距離に基づレ、 て、移動体の位置を測位することを特徴とする。 The positioning means measures the position of the moving body based on the pseudo distance filtered by the filter means.
発明の効果 The invention's effect
[0013] 本発明によれば、移動体が停止して V、る状況下で、衛星信号の搬送波位相の計測 結果を用いずに別の手段により擬似距離変化量を推定して、擬似距離のフィルタリ ングを可能とする移動体位置測位装置が得られる。
図面の簡単な説明 [0013] According to the present invention, the pseudo-range change amount is estimated by another means without using the measurement result of the carrier wave phase of the satellite signal under the situation where the moving body stops and becomes V. A mobile body positioning device capable of filtering can be obtained. Brief Description of Drawings
[0014] [図 1]本発明に係る移動体位置測位装置が適用される GPSの全体的な構成を示す システム構成図である。 FIG. 1 is a system configuration diagram showing an overall configuration of GPS to which a mobile body positioning device according to the present invention is applied.
[図 2]図 1の車両 90に搭載される GPS受信機 1の一実施例を示す概略的なシステム 構成図である。 FIG. 2 is a schematic system configuration diagram showing an embodiment of a GPS receiver 1 mounted on the vehicle 90 in FIG.
[図 3]ワールド座標系とローカル座標系との関係を示す図である。 FIG. 3 is a diagram showing the relationship between the world coordinate system and the local coordinate system.
[図 4]実施例 1に係る擬似距離変化量推定部 50Aによる擬似距離変化量推定処理 の要部を示すフローチャートである。 FIG. 4 is a flowchart showing a main part of a pseudo distance change amount estimation process by a pseudo distance change amount estimation unit 50A according to the first embodiment.
[図 5]実施例 2に係る GPS受信機 2の要部構成を示す概略的なシステム構成図であ FIG. 5 is a schematic system configuration diagram showing the main configuration of a GPS receiver 2 according to a second embodiment.
[図 6]実施例 2に係る擬似距離変化量推定部 50Aによる擬似距離変化量推定処理 の要部を示すフローチャートである。 FIG. 6 is a flowchart showing a main part of pseudo distance change amount estimation processing by a pseudo distance change amount estimation unit 50A according to the second embodiment.
[図 7]実施例 3に係る GPS受信機 3の要部構成を示す概略的なシステム構成図であ FIG. 7 is a schematic system configuration diagram showing the main configuration of a GPS receiver 3 according to Example 3.
[図 8]実施例 3に係る擬似距離変化量推定部 50Cによる擬似距離変化量推定処理 の一例の要部を示すフローチャートである。 FIG. 8 is a flowchart showing a main part of an example of pseudo distance change amount estimation processing by a pseudo distance change amount estimation unit 50C according to the third embodiment.
符号の説明 Explanation of symbols
[0015] 1,2, 3 GPS受信機 [0015] 1,2, 3 GPS receiver
10 GPS衛星 10 GPS satellite
20A, 20B 受信部 20A, 20B receiver
30 フィルタ 30 filters
40 測位演算部 40 Positioning calculator
50A,50B,50C 擬似距離変化量推定部 50A, 50B, 50C Pseudo-range change estimation unit
60 衛星位置算出部 60 Satellite position calculator
70 停止判定部 70 Stop judgment section
80 外部センサ 80 External sensor
90 車両 90 vehicles
発明を実施するための最良の形態
[0016] 以下、図面を参照して、本発明を実施するための最良の形態の説明を行う。 BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
実施例 1 Example 1
[0017] 図 1は、本発明に係る移動体位置測位装置が適用される GPS (Global Positioning System)の全体的な構成を示すシステム構成図である。図 1に示すように、 GPSは、 地球周りを周回する GPS衛星 10と、地球上に位置し地球上を移動しうる車両 90とか ら構成される。尚、車両 90は、あくまで移動体の一例であり、その他の移動体として は、自動二輪車、鉄道、船舶、航空機、ホークリフト、ロボットや、人の移動に伴い移 動する携帯電話等の情報端末等がありうる。 FIG. 1 is a system configuration diagram showing an overall configuration of a GPS (Global Positioning System) to which a mobile body positioning device according to the present invention is applied. As shown in Fig. 1, GPS is composed of a GPS satellite 10 that orbits the earth and a vehicle 90 that is located on the earth and can move on the earth. The vehicle 90 is merely an example of a moving body, and other moving bodies include information terminals such as motorcycles, railways, ships, airplanes, hawk lifts, robots, and mobile phones that move as people move. And so on.
[0018] GPS衛星 10は、航法メッセージ (衛星信号)を地球に向けて常時放送する。航法メ ッセージには、対応する GPS衛星 10に関する衛星軌道情報(エフヱメリスやアルマ ナク)、時計の補正値、電離層の補正係数が含まれている。航法メッセージは、 C/A コードにより拡散され L1波(周波数: 1575.42MHz)に乗せられて、地球に向けて常 時放送されている。尚、 L1波は、 C/Aコードで変調された Sin波と Pコード(Precisio n Code)で変調された Cos波の合成波であり、直交変調されている。 C/Aコード及 び Pコードは、擬似雑音(Pseudo Noise)符号であり、— 1と 1が不規則に周期的に並 ぶ符号列である。 [0018] The GPS satellite 10 constantly broadcasts navigation messages (satellite signals) toward the earth. The navigation message includes satellite orbit information (F-Merith and Almanac) for the corresponding GPS satellite 10, clock correction values, and ionospheric correction factors. The navigation message is spread by the C / A code and carried on the L1 wave (frequency: 1575.42 MHz), and is constantly broadcast to the earth. The L1 wave is a combined wave of a sine wave modulated with a C / A code and a Cos wave modulated with a P code (Precision Code), and is orthogonally modulated. The C / A code and the P code are pseudo noise codes, which are code strings in which 1 and 1 are arranged irregularly and periodically.
[0019] 尚、現在、 24個の GPS衛星 10が高度約 20, OOOKm上空で地球を一周しており、 各 4個の GPS衛星 10が 55度ずつ傾いた 6つの地球周回軌道面に均等に配置され ている。従って、天空が開けている場所であれば、地球上のどの場所にいても、常時 、少なくとも 5個以上の GPS衛星 10が観測可能である。 [0019] Currently, 24 GPS satellites 10 orbit the earth at an altitude of about 20, OOOKm, and each of the four GPS satellites 10 is evenly distributed on six orbiting earth orbits inclined by 55 degrees. It is arranged. Therefore, as long as the sky is open, at least 5 GPS satellites 10 can be observed at any time on the earth.
[0020] 車両 90には、移動体位置測位装置としての GPS受信機 1が搭載される。 GPS受信 機 1は、以下で詳説する如ぐ GPS衛星 10からの衛星信号に基づいて、車両 90の 位置を測位する。 [0020] The vehicle 90 is equipped with a GPS receiver 1 as a mobile body positioning device. The GPS receiver 1 measures the position of the vehicle 90 based on the satellite signal from the GPS satellite 10 as described in detail below.
[0021] 図 2は、図 1の車両 90に搭載される GPS受信機 1の一実施例を示す概略的なシス テム構成図である。図 2には、説明の複雑化を避けるため、 GPS衛星 10 (下付きの 符号は、衛星番号)が 1つだけ示されている。ここでは、 GPS衛星 10力、らの衛星信 号に関する信号処理について代表して説明する。 GPS衛星 10力 の衛星信号に 関する信号処理は、他の GPS衛星 10 , 10等からの衛星信号に関する信号処理と
実質的に同じである。 FIG. 2 is a schematic system configuration diagram showing an embodiment of the GPS receiver 1 mounted on the vehicle 90 of FIG. Figure 2 shows only one GPS satellite 10 (the subscript is the satellite number) to avoid complexity. Here, the signal processing related to GPS satellite 10 power and other satellite signals will be explained as a representative. The signal processing related to the satellite signal of the GPS satellite 10 power is the same as the signal processing related to the satellite signal from other GPS satellites 10 and 10 etc. It is substantially the same.
[0022] 本実施例の GPS受信機 1は、図 2に示すように、主要な機能部として、受信部 20A 、フィルタ 30、測位演算部 40、擬似距離変化量推定部 50A、衛星位置算出部 60、 及び、停止判定部 70を備える。 As shown in FIG. 2, the GPS receiver 1 of the present embodiment includes, as main functional units, a receiving unit 20A, a filter 30, a positioning calculation unit 40, a pseudo-range change amount estimating unit 50A, a satellite position calculating unit. 60 and a stop determination unit 70 are provided.
[0023] 受信部 20Aは、 GPS衛星 10力も発信されている衛星信号を GPSアンテナ 22を介 して受信し、内部で発生させたレプリカ C/Aコードを用いて C/Aコード同期を行い 、航法メッセージを取り出すと共に、 GPS衛星 10と車両 90 (正確には GPS受信機 1 )との間の擬似距離 p,を算出する。擬似距離 p,とは、 GPS衛星 10と車両 90との 間の真の距離とは異なり、時計誤差 (クロックバイアス)や電波伝搬速度変化による誤 差を含む。 C/Aコード同期の方法は、多種多様でありえ、任意の適切な方法が採 用されてよい。例えば、 DDL (Delay— Locked [0023] The receiving unit 20A receives a satellite signal from which 10 GPS satellites are transmitted via the GPS antenna 22, and performs C / A code synchronization using a replica C / A code generated internally. The navigation message is extracted, and the pseudo distance p between the GPS satellite 10 and the vehicle 90 (more precisely, the GPS receiver 1) is calculated. The pseudorange p is different from the true distance between the GPS satellite 10 and the vehicle 90, and includes errors due to clock error (clock bias) and changes in radio wave propagation speed. The method of C / A code synchronization can vary widely, and any appropriate method may be employed. For example, DDL (Delay— Locked
Loop)を用いて、受信した C/Aコードに対するレプリカ C/Aコードの相関値がピー クとなるコード位相を追尾する方法であってよい。尚、符号の意味として、擬似距離 p に付された「 '」は、後述のフィルタ処理が実行されて!/、な!/、ことを示す。 Loop) may be used to track the code phase at which the correlation value of the replica C / A code with respect to the received C / A code becomes a peak. In addition, as a meaning of a code, “′” added to the pseudo distance p indicates that a filter process described later is executed! /,! /.
[0024] ここで、 GPS衛星 10に対する擬似距離 p,は、例えば以下のように算出されてよ い。 Here, the pseudo distance p, relative to the GPS satellite 10, may be calculated as follows, for example.
p ' =N X 300 p '= N X 300
ここで、 Nは、 GPS衛星 10と車両 90との間の C/Aコードのビット数に相当し、レプリ 力 C/Aコードの位相及び GPS受信機 1内部の受信機時計に基づいて算出される。 尚、数ィ直 300は、 C/Aコード力 1ビットの長さが 1 3であり、 1ビットに相当する長さ が約 300m (l μ s X光速)であることに由来する。このようにして算出された擬似距離 P 'を表す信号は、フィルタ 30に入力される。 Here, N corresponds to the number of bits of the C / A code between the GPS satellite 10 and the vehicle 90, and is calculated based on the phase of the replication C / A code and the receiver clock inside the GPS receiver 1. The The number 300 is derived from the fact that the length of 1 bit of C / A coding power is 13 and the length corresponding to 1 bit is about 300 m (l μ s X speed of light). A signal representing the pseudo distance P ′ calculated in this way is input to the filter 30.
[0025] 擬似距離変化量推定部 50Aは、観測周期間の擬似距離変化量 Δ p (観測周期間 の車両 90に対する GPS衛星 10の相対移動量に相当)を推定する。推定方法の詳 細については後述する。 The pseudo-range change amount estimation unit 50A estimates the pseudo-range change amount Δ p (corresponding to the relative movement amount of the GPS satellite 10 with respect to the vehicle 90 during the observation period) during the observation period. Details of the estimation method will be described later.
[0026] フィルタ 30では、擬似距離変化量推定部 50Aにより推定される擬似距離変化量 Δ [0026] In the filter 30, the pseudo distance change amount Δ estimated by the pseudo distance change amount estimation unit 50A
βを用いて、擬似距離 ρ 'のフィルタ処理が実行される。フィルタ 30では、例えば以 下の演算式に従って、フィルタ処理後の擬似距離 ρが導出される。
[0027] [数 1] Using β, the filter processing of the pseudorange ρ ′ is executed. In the filter 30, for example, the pseudo distance ρ after filtering is derived according to the following arithmetic expression. [0027] [Equation 1]
ここで、 (i)は今回値を表し、(i 1)は前回値を表し、 Mは、重み係数である。 Mの値 は、精度と応答性を考慮しつつ適切に決定される。 Δνの時間積分の項は、観測周 期間の擬似距離変化量に相当し、上述の如く擬似距離変化量推定部 50Αにより推 定される擬似距離変化量 Δ ρが代入されることになる、尚、フィルタ 30でのフィルタリ ング(スム一ジング)は、上述のハッチフィルタ以外のフィルタ、例えばカルマンフィル タを用いて実現することも可能である。フィルタ処理後の擬似距離 ρを表す信号は、 測位演算部 40に入力される。 Here, (i) represents the current value, (i 1) represents the previous value, and M is a weighting factor. The value of M is appropriately determined in consideration of accuracy and responsiveness. The term of time integration of Δν corresponds to the pseudorange change amount in the observation period, and the pseudorange change amount Δρ estimated by the pseudorange change amount estimation unit 50 推定 is substituted as described above. The filtering (smoothing) in the filter 30 can also be realized using a filter other than the above-described hatch filter, for example, a Kalman filter. A signal representing the pseudorange ρ after filtering is input to the positioning calculation unit 40.
[0028] 衛星位置算出部 60は、航法メッセージの衛星軌道情報及び現在の時間に基づレ、 て、 GPS衛星 10の、ワールド座標系での現在位置 (X、 Υ、 Ζ )を計算する。尚、 G PS衛星 10は、人工衛星の 1つであるので、その運動は、地球重心を含む一定面内 (軌道面)に限定される。また、 GPS衛星 10の軌道は地球重心を 1つの焦点とする 楕円運動であり、ケプラーの方程式を逐次数値計算することで、軌道面上での GPS 衛星 10の位置が計算できる。また、 GPS衛星 10の位置 (X、 Υ、 Ζ )は、 GPS衛 星 10の軌道面とワールド座標系の赤道面が回転関係にあることを考慮して、軌道面 上での GPS衛星 10の位置を 3次元的な回転座標変換することで得られる。尚、ヮー ルド座標系とは、図 3に示すように、地球重心を原点として、赤道面内で互いに直交 する X軸及び Υ軸、並びに、この両軸に直交する Ζ軸により定義される。衛星位置 (X 、 Υ、 Ζ )を表す信号は、測位演算部 40及び擬似距離変化量推定部 50Αに入力さ れる。 [0028] The satellite position calculation unit 60 calculates the current position (X, Υ, Ζ) of the GPS satellite 10 in the world coordinate system based on the satellite orbit information of the navigation message and the current time. Since the GPS satellite 10 is one of artificial satellites, its movement is limited to a certain plane (orbital plane) including the center of gravity of the earth. The orbit of the GPS satellite 10 is an elliptical motion with the center of gravity of the earth as one focal point, and the position of the GPS satellite 10 on the orbital plane can be calculated by sequentially calculating the Kepler equation. In addition, the position of the GPS satellite 10 (X, Υ, 、) is determined based on the rotational relationship between the orbital plane of the GPS satellite 10 and the equatorial plane of the world coordinate system. It can be obtained by converting the position into a three-dimensional rotational coordinate. As shown in Fig. 3, the field coordinate system is defined by the X axis and the X axis that are orthogonal to each other in the equator plane, and the X axis that is orthogonal to both axes with the center of gravity of the earth as the origin. Signals representing the satellite positions (X, Υ, Ζ) are input to the positioning calculation unit 40 and the pseudo-range change estimation unit 50Α.
[0029] 測位演算部 40は、衛星位置の算出結果と、フィルタ 30から供給される擬似距離 ρ の算出結果に基づいて、車両 90の位置 (X , Υ , Ζ )を測位する。測位の演算周期
は、例えば観測周期(例えば lms)或いは所定数の観測周期(例えば 50msや 100 ms)であってよい。測位結果は、擬似距離変化量推定部 50Aに供給されると共に、 例えばナビゲーシヨンシステムに供給される。車両 90の位置は、 3つの GPS衛星 10 に対して得られるそれぞれの擬似距離 p及び衛星位置を用いて、三角測量の原理 で導出されてよい。この場合、擬似距離 pは上述の如く時計誤差を含むので、 4つ目 の GPS衛星 10に対して得られる擬似距離 p及び衛星位置を用いて、時計誤差成分 が除去される。尚、車両 90の位置の測位方法としては、上述のような単独測位に限ら れず、干渉測位 (既知の点に設置された固定局での受信データを併用する方式)で あってもよい。干渉測位の場合、上述の如く固定局及び車両 90にてそれぞれ得られ る擬似距離 pの一重位相差や 2重位相差等を用いて車両 90の位置が測位されるこ とになる。 [0029] The positioning calculation unit 40 measures the position (X, Υ, Ζ) of the vehicle 90 based on the calculation result of the satellite position and the calculation result of the pseudo distance ρ supplied from the filter 30. Positioning calculation cycle May be, for example, an observation period (eg, lms) or a predetermined number of observation periods (eg, 50 ms or 100 ms). The positioning result is supplied to the pseudo distance change amount estimation unit 50A and also supplied to, for example, a navigation system. The position of the vehicle 90 may be derived on the principle of triangulation using the respective pseudoranges p and satellite positions obtained for the three GPS satellites 10. In this case, since the pseudo distance p includes a clock error as described above, the clock error component is removed using the pseudo distance p and the satellite position obtained for the fourth GPS satellite 10. The positioning method of the position of the vehicle 90 is not limited to the single positioning as described above, but may be interference positioning (a method in which received data at a fixed station installed at a known point is used in combination). In the case of interference positioning, the position of the vehicle 90 is measured using the single phase difference or double phase difference of the pseudo distance p obtained by the fixed station and the vehicle 90 as described above.
停止判定部 70は、車輪速センサの出力信号に基づいて、車両 90が停止している か否かを判定する。具体的には、停止判定部 70は、車輪速センサの出力値(車速) に基づく指標値が所定閾値を下回った場合に、車両 90が停止して!/、ると判定する。 指標値は、例えば、車速であってもよいし、車速を時間積分したものであってもよい。 所定閾値は、車両停止時と移動時の指標値の特性に応じて実験的に適合されてよ い。車輪速センサは、車両 90の各輪に搭載され、車輪の回転速度に応じた車速パ ノレスを出力するものであってよい。この場合、停止判定部 70は、四輪全ての車輪速 センサの出力信号に基づいて判定してもよいし、何れかの車輪速センサの出力信号 に基づいて判定してもよい。また、停止判定部 70は、車輪速センサに代えて若しくは それに加えて、トランスミッションの出力軸の回転数を測定するセンサ等のような、車 速に関連する物理量を出力できる他の車載センサを用いて、車両 90が停止している か否かを判定してもよい。或いは、停止判定部 70は、測位演算部 40から取得可能な 測位結果に基づいて、車両 90が停止しているか否かを判定してもよい。具体的には 、停止判定部 70は、車両 90の位置情報に基づく指標値が所定閾値を下回った場合 に、車両 90が停止していると判定する。指標値は、例えば、測位演算部 40の測位結 果に基づく車両位置の時間変化(即ち車両 90の速度)であってもよいし、それを時間 積分したものであってもよい。所定閾値は、車両停止時と移動時の指標値の特性に
応じて実験的に適合されてよい。或いは、停止判定部 70は、加速度センサ及びョー レートセンサの出力信号に基づいて、車両 90が停止しているか否かを判定してもよ い。具体的には、停止判定部 70は、加速度センサ及びョーレートセンサのそれぞれ の出力値を時間微分し、当該それぞれの微分値が、それぞれに対して設定された閾 値を下回った場合に、車両 90が停止していると判定する。尚、加速度センサ及びョ 一レートセンサは、好ましくは、互いに直交する 3軸に沿った加速度、及び、 3軸まわ りのョーレートを検出する。この場合、 6種類の出力値の微分値 (指標値)が、それぞ れ別々に、それぞれに対して設定された閾値と比較されることになる。この場合、停 止判定部 70は、 6種類の出力値の微分値が全て、それぞれに対して設定された各 閾値を下回った場合に、車両 90が停止していると判定する。各閾値は、車両停止時 と移動時の各指標値 (微分値)の特性の相違に応じて実験的に適合されてよい。或 いは、停止判定部 70は、上述の 3種類の判定方法の全て若しくは任意の 2つの組み 合わせの判定結果をアンド条件として、車両 90が停止して!/、るか否かを判定してもよ い。 The stop determination unit 70 determines whether or not the vehicle 90 is stopped based on the output signal of the wheel speed sensor. Specifically, the stop determination unit 70 determines that the vehicle 90 stops and is! / When the index value based on the output value (vehicle speed) of the wheel speed sensor falls below a predetermined threshold. The index value may be, for example, a vehicle speed, or may be a value obtained by integrating the vehicle speed over time. The predetermined threshold may be experimentally adapted according to the characteristics of the index values when the vehicle is stopped and when moving. The wheel speed sensor may be mounted on each wheel of the vehicle 90 and output a vehicle speed panel according to the rotational speed of the wheel. In this case, the stop determination unit 70 may make the determination based on the output signals from all the wheel speed sensors, or may make the determination based on the output signals from any of the wheel speed sensors. The stop determination unit 70 uses other in-vehicle sensors that can output a physical quantity related to the vehicle speed, such as a sensor that measures the rotation speed of the output shaft of the transmission instead of or in addition to the wheel speed sensor. Thus, it may be determined whether or not the vehicle 90 is stopped. Alternatively, the stop determination unit 70 may determine whether or not the vehicle 90 is stopped based on the positioning result that can be acquired from the positioning calculation unit 40. Specifically, the stop determination unit 70 determines that the vehicle 90 is stopped when the index value based on the position information of the vehicle 90 falls below a predetermined threshold. The index value may be, for example, a time change of the vehicle position (that is, the speed of the vehicle 90) based on the positioning result of the positioning calculation unit 40, or may be a value obtained by integrating the time. The predetermined threshold depends on the characteristics of the index value when the vehicle is stopped and moving. It may be adapted experimentally accordingly. Alternatively, the stop determination unit 70 may determine whether or not the vehicle 90 is stopped based on output signals from the acceleration sensor and the parallel sensor. Specifically, the stop determination unit 70 time-differentiates each output value of the acceleration sensor and the parallel sensor, and when the respective differential value falls below a threshold value set for each, the vehicle 90 is Judge that it is stopped. Note that the acceleration sensor and the single rate sensor preferably detect acceleration along three axes that are orthogonal to each other and a high rate around the three axes. In this case, the differential values (index values) of the six types of output values are individually compared with the threshold values set for each. In this case, the stop determination unit 70 determines that the vehicle 90 is stopped when all the differential values of the six types of output values are below the respective threshold values set for each. Each threshold value may be experimentally adapted according to the difference in characteristics of each index value (differential value) when the vehicle is stopped and when the vehicle is moving. Alternatively, the stop determination unit 70 determines whether or not the vehicle 90 is stopped! /, Using the determination results of all or any two combinations of the above three types of determination methods as AND conditions. It's okay.
[0031] 停止判定部 70による判定結果は、擬似距離変化量推定部 50Aに供給される。例 えば、停止判定部 70による判定結果は、停止/移動フラグで表現されてもよい。具 体的には、停止判定部 70は、車両 90が停止していると判定した場合、例えば、停止 /移動フラグを立てる。一方、車両 90が停止していないと判定した場合、停止/移 動フラグを降ろす。この停止/移動フラグの状態は、擬似距離変化量推定部 50Aに より参照されることになる。 The determination result by the stop determination unit 70 is supplied to the pseudo distance change amount estimation unit 50A. For example, the determination result by the stop determination unit 70 may be expressed by a stop / movement flag. Specifically, when the stop determination unit 70 determines that the vehicle 90 is stopped, for example, a stop / movement flag is set. On the other hand, if it is determined that the vehicle 90 has not stopped, the stop / movement flag is cleared. The state of the stop / movement flag is referred to by the pseudo distance change amount estimation unit 50A.
[0032] 次に、図 4を参照して、擬似距離変化量推定部 50Aによる擬似距離変化量推定処 理について説明する。図 4は、擬似距離変化量推定部 50Aによる擬似距離変化量 推定処理の一例の要部を示すフローチャートである。図 4に示す処理ルーチンは、 所定周期毎 (例えば、測位演算部 40の測位の演算周期毎)に繰り返し実行されてよ い。 Next, with reference to FIG. 4, the pseudo distance change estimation processing by the pseudo distance change estimation unit 50A will be described. FIG. 4 is a flowchart showing a main part of an example of the pseudo distance change estimation process performed by the pseudo distance change estimation unit 50A. The processing routine shown in FIG. 4 may be repeatedly executed every predetermined cycle (for example, every positioning calculation cycle of the positioning calculation unit 40).
[0033] ステップ 100では、擬似距離変化量推定部 50Aは、停止判定部 70による判定結果 を取得する。 [0033] In step 100, the pseudo distance change amount estimation unit 50A acquires the determination result by the stop determination unit 70.
[0034] ステップ 110では、擬似距離変化量推定部 50Aは、衛星位置算出部 60からの衛
星位置情報に基づいて、 GPS衛星 1(^の移動ベクトルを算出すると共に、衛星位置 算出部 60からの衛星位置情報及び測位演算部 40からの車両 90の位置情報に基づ いて、車両 90の位置を基準とした GPS衛星 10の位置ベクトル(以下、「視線べタト ノレ」と称する)を算出する。具体的には、 GPS衛星 10の移動ベクトルは、今回周期 で得られる GPS衛星 10の位置 (X (i)、Y (i)、Z (i) )から、前回周期で得られる G ps衛星 10の位置 (X (i— υ、γ (ί— υ、 ζ (i—υ)を差し引くことで導出されても よい。また、視線ベクトルは、今回周期で得られる GPS衛星 lC^の位置 (X i Y i) 、 Z (i) )から、前回周期で得られる車両 90の位置 (X (i- 1) , Y (i- 1) , Z (i- 1) ) を差し引くことで導出されてもよい。尚、移動ベクトルは、衛星位置算出部 60にて算 出されてもよい。また、ステップ 100と 110の処理順序は逆であってもよい。 [0034] In step 110, the pseudo-range variation estimating unit 50A receives the guard from the satellite position calculating unit 60. Based on the star position information, the movement vector of GPS satellite 1 (^ is calculated, and based on the satellite position information from the satellite position calculation unit 60 and the position information of the vehicle 90 from the positioning calculation unit 40, the vehicle 90 Calculates the position vector of GPS satellite 10 based on the position (hereinafter referred to as “line of sight line”), specifically, the movement vector of GPS satellite 10 is the position of GPS satellite 10 obtained in this cycle. Subtract the position (X (i— υ, γ (ί— υ, ζ (i—υ)) of the G ps satellite 10 obtained in the previous cycle from (X (i), Y (i), Z (i)) The line-of-sight vector can be derived from the position (X i Y i), Z (i)) of the GPS satellite lC ^ obtained in the current cycle, and the position of the vehicle 90 (X It may be derived by subtracting (i-1), Y (i-1), Z (i-1)), and the movement vector may be calculated by the satellite position calculation unit 60. In addition, The processing order of steps 100 and 110 may be reversed.
[0035] ステップ 120では、擬似距離変化量推定部 50Aは、停止判定部 70による判定結果 In step 120, the pseudo distance change amount estimation unit 50A determines the determination result by the stop determination unit 70.
(停止/移動フラグの状態)に基づいて、車両 90が停止しているか否かを判定する。 停止判定部 70により車両 90が停止していると判定されている場合には、ステップ 14 0に進み、それ以外の場合には、ステップ 130に進む。 Based on (the state of the stop / movement flag), it is determined whether or not the vehicle 90 is stopped. If it is determined by the stop determination unit 70 that the vehicle 90 is stopped, the process proceeds to step 140. Otherwise, the process proceeds to step 130.
[0036] ステップ 130では、擬似距離変化量推定部 50Aは、擬似距離変化量 Δ pを推定し ない。即ち、停止判定部 70により車両 90が停止していないと判定されている間には 、擬似距離変化量推定部 50Aにより擬似距離変化量 Δ pが推定されない。この場 合、上述のフィルタ 30の機能は実質的に停止した状態となる。即ち、測位演算部 40 は、受信部 20Aからの擬似距離 P 'を直接用いて測位を実行する。 In step 130, the pseudo distance change amount estimation unit 50A does not estimate the pseudo distance change amount Δp. In other words, while the stop determination unit 70 determines that the vehicle 90 is not stopped, the pseudo distance change amount Δp is not estimated by the pseudo distance change amount estimation unit 50A. In this case, the function of the filter 30 described above is substantially stopped. That is, the positioning calculation unit 40 performs positioning by directly using the pseudo distance P ′ from the receiving unit 20A.
[0037] ステップ 140では、擬似距離変化量推定部 50Aは、上記のステップ 110から得られ る GPS衛星 10の移動ベクトルと視線ベクトルとを用いて、擬似距離変化量 Δ pを推 定する。具体的には、擬似距離変化量 Δ Pは、移動ベクトルと視線ベクトルとの内積 により導出されてよい。尚、視線ベクトルは、上述の如く前回周期で得られる車両 90 の位置を用いているが、車両 90が停止した状態のときは、今回周期で得られるべき 車両 90の位置は、前回周期で得られる車両 90の位置と同一であるとみなすことがで きるので不都合はない。或いは、擬似距離変化量推定部 50Αは、今回周期での視 線ベクトルの大きさ L (i)力、ら前回周期での視線ベクトルの大きさ L (i 1)を差し引レ、 て得られる差分値( = L (i) L (i 1) )を、擬似距離変化量 Δ pとして推定してもよ
い。この場合、今回周期での視線ベクトルの大きさ L (i)は、車両 90が停止しているこ とを利用して、今回周期で得られる GPS衛星 10の位置 (X (i)、Y (i)、Z (i) )から、 前回周期で得られる車両 90の位置 (X (i- 1) , Y (i- 1) , Z (i— 1) )を差し引いて 得られるベクトルの大きさを求めることで、導出されてよい。同様に、前回周期での視 線ベクトルの大きさ L (i 1)は、前回周期で得られる GPS衛星 10 の位置(X (i- 1) 、Y (i—l)、Z (i—l) )から、前回周期で得られる車両 90の位置 (X (i- 1) , Y (i- 1) , Z (i 1) )を差し引いて得られるベクトルの大きさを求めることで、導出されてよ い。このようにして推定された擬似距離変化量 Δ pは、上述の如くフィルタ 30に入力 され、擬似距離 p 'のスムージングに利用される。 [0037] In step 140, the pseudo-range change estimation unit 50A estimates the pseudo-range change Δp using the movement vector and the line-of-sight vector of the GPS satellite 10 obtained from step 110 described above. Specifically, pseudorange change amount delta P may be derived by the inner product of the movement vector and the viewing vector. The line-of-sight vector uses the position of the vehicle 90 obtained in the previous cycle as described above. However, when the vehicle 90 is stopped, the position of the vehicle 90 that should be obtained in the current cycle is obtained in the previous cycle. This is not inconvenient because it can be considered to be the same as the position of the vehicle 90 to be mounted. Alternatively, the pseudo distance change amount estimation unit 50Α can be obtained by subtracting the magnitude L (i) of the line-of-sight vector in the current cycle and the magnitude L (i 1) of the line-of-sight vector in the previous cycle. The difference value (= L (i) L (i 1)) may be estimated as the pseudorange change Δ p. Yes. In this case, the magnitude L (i) of the line-of-sight vector in the current cycle is obtained by using the position of the GPS satellite 10 (X (i), Y ( i), Z (i)), the size of the vector obtained by subtracting the position (X (i-1), Y (i-1), Z (i--1)) of the vehicle 90 obtained in the previous cycle May be derived. Similarly, the magnitude L (i 1) of the line-of-sight vector in the previous cycle is the position of the GPS satellite 10 obtained in the previous cycle (X (i-1), Y (i-l), Z (i-l )) Is derived by subtracting the position (X (i- 1), Y (i- 1), Z (i 1)) of the vehicle 90 obtained in the previous cycle. Good. The pseudo-range change Δp estimated in this way is input to the filter 30 as described above and used for smoothing the pseudo-range p ′.
[0038] 以上説明した実施例 1による構成によれば、とりわけ、以下のような優れた効果が奏 される。 [0038] According to the configuration of the first embodiment described above, the following excellent effects can be obtained.
[0039] 上述の如ぐ車両 90の停止状態において擬似距離 ρ 'のスムージングを行うことで 、車両 90の停止状態における擬似距離 pの精度、ひいては車両 90の位置の精度を 高めること力 Sできる。また、擬似距離変化量 Δ pを衛星位置情報に基づいて推定す るので、擬似距離 p 'のキャリアスムージングを行う際に必要なドップラー周波数変化 量を導出する必要がなくなる。従って、衛星信号の搬送波位相を測定する機能を省 いた安価な GPS受信機 1を用いた場合であっても、車両 90の停止状態において擬 似距離 p 'のスムージングを行うことができる。 [0039] By performing the smoothing of the pseudo distance ρ 'when the vehicle 90 is stopped as described above, it is possible to increase the accuracy S of the pseudo distance p when the vehicle 90 is stopped, and hence the accuracy of the position of the vehicle 90. In addition, since the pseudo distance change Δp is estimated based on the satellite position information, it is not necessary to derive the Doppler frequency change necessary for carrier smoothing of the pseudo distance p ′. Therefore, even when the inexpensive GPS receiver 1 that omits the function of measuring the carrier wave phase of the satellite signal is used, the pseudo distance p ′ can be smoothed when the vehicle 90 is stopped.
実施例 2 Example 2
[0040] 実施例 2は、上述の実施例 1に対して、車両 90が移動状態にあるときと停止状態に あるときとで、擬似距離変化量 Δ pを異なる推定態様で推定する点が主に異なる。 以下では、実施例 2特有の構成について重点的に説明する。その他の構成につい ては、上述の実施例 1と同様であってよい。 [0040] The second embodiment is different from the first embodiment in that the pseudo-range change amount Δp is estimated in different estimation modes when the vehicle 90 is in a moving state and when it is in a stopped state. Different. In the following, the configuration peculiar to the second embodiment will be described mainly. Other configurations may be the same as those in the first embodiment.
[0041] 図 5は、実施例 2に係る GPS受信機 2の要部構成を示す概略的なシステム構成図 である。図 5において、上述の実施例 1と同様の構成については同一の参照符号が 付されており、それらの説明は省略する。また、 GPS衛星 10力 の衛星信号に関す る信号処理にっレ、て代表して説明する。 FIG. 5 is a schematic system configuration diagram showing the main configuration of the GPS receiver 2 according to the second embodiment. In FIG. 5, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In addition, the signal processing related to the satellite signal of 10 GPS satellites will be described as a representative.
[0042] 受信部 20Bは、 GPS衛星 10力も発信されている衛星信号を GPSアンテナ 22を介
して受信し、内部で発生させたレプリカ C/Aコードを用いて C/Aコード同期を行い 、航法メッセージを取り出すと共に、 GPS衛星 10と車両 90 (正確には GPS受信機 2 )との間の擬似距離 P 'を算出する。更に、受信部 20Bは、衛星信号の搬送波位相を 測定する機能を備え、内部で発生させたレプリカキャリアを用いて、ドップラーシフトし た受信搬送波のドップラー周波数変化量 Δ fを測定する機能を備える。ドップラー周 波数変化量 A fは、レプリカキャリアの周波数 frと既知の搬送波周波数 f (1575.42M[0042] The receiving unit 20B transmits a satellite signal from which GPS satellite 10 power is transmitted via the GPS antenna 22. The C / A code is synchronized using the replica C / A code generated internally, and the navigation message is taken out, and between the GPS satellite 10 and the vehicle 90 (precisely the GPS receiver 2). Calculate the pseudorange P ′ of. Furthermore, the receiving unit 20B has a function of measuring the carrier wave phase of the satellite signal, and has a function of measuring the Doppler frequency change amount Δf of the Doppler-shifted received carrier wave using a replica carrier generated inside. The Doppler frequency variation A f is the replica carrier frequency fr and the known carrier frequency f (1575.42M
Hz)の差分( = fr— f )として測定される。この機能は、レプリカキャリアを用いてキヤリ ァ相関値を演算して受信キャリアを追尾する PLL (Phase— Locked Hz) difference (= fr – f). This function is a PLL (Phase—Locked) that uses a replica carrier to calculate the carrier correlation value and track the received carrier.
Loop)により実現されてよい。ドップラー周波数変化量 A fを表す信号は、擬似距離 変化量推定部 50Bに入力される。 Loop). A signal representing the Doppler frequency change amount A f is input to the pseudo-range change amount estimation unit 50B.
[0043] 図 6は、実施例 2に係る擬似距離変化量推定部 50Bによる擬似距離変化量推定処 理の一例の要部を示すフローチャートである。図 6に示す処理ルーチンは、所定周 期毎 (例えば、測位の演算周期毎)に繰り返し実行されてよい。図 6に示す処理のうち 、上述の実施例 1に係る図 4に示す処理と同様の処理については、同一のステップ 番号を付して説明を省略する。 FIG. 6 is a flowchart illustrating a main part of an example of the pseudo distance variation estimation process by the pseudo distance variation estimation unit 50B according to the second embodiment. The processing routine shown in FIG. 6 may be repeatedly executed every predetermined period (for example, every positioning calculation period). Among the processes shown in FIG. 6, the same processes as those shown in FIG. 4 according to the first embodiment are denoted by the same step numbers and the description thereof is omitted.
[0044] ステップ 150では、擬似距離変化量推定部 50Bは、受信部 20Bから得られるドッブ ラー周波数変化量 A fに基づいて、擬似距離変化量 Δ pを推定する。例えば、ドッブ ラー周波数変化量 A fに基づいて、 GPS衛星 10と車両 90との間の相対速度 Δνが 、例えば以下の関係式を用いて、算出される。 [0044] In step 150, the pseudo distance change amount estimating unit 50B estimates the pseudo distance change amount Δp based on the Doppler frequency change amount A f obtained from the receiving unit 20B. For example, the relative speed Δν between the GPS satellite 10 and the vehicle 90 is calculated based on the Doppler frequency change amount A f using, for example, the following relational expression.
A f = AV-f / (c AV) A f = AV-f / (c AV)
c c
ここで、 cは光速である。次いで、擬似距離変化量 Δ ρは、相対速度 Δνを時間積分 することにより導出される。積分期間は、処理ルーチンの周期に対応するものであつ てよい。このようにして推定された擬似距離変化量 Δ ρは、上述の如くフィルタ 30に 入力され、上述の式 1の Δνの時間積分の項に代入されることにより、擬似距離 ρ ' のスムージング(いわゆるキャリアスムージング)に利用される。 Where c is the speed of light. Next, the pseudo-range change Δρ is derived by time-integrating the relative speed Δν. The integration period may correspond to the period of the processing routine. The pseudo-range variation Δρ estimated in this way is input to the filter 30 as described above, and is substituted into the term of the time integration of Δν in the above-described equation 1, thereby smoothing the pseudo-range ρ ′ (so-called Used for carrier smoothing.
[0045] 以上説明した実施例 1による構成によれば、とりわけ、以下のような優れた効果が奏 される。 [0045] According to the configuration of the first embodiment described above, the following excellent effects can be obtained.
[0046] 車両 90の停止状態では、上述の実施例 1と同様の方法で、衛星位置情報に基づ
いて擬似距離変化量 Δ pを推定し、車両 90の移動状態では、ドップラー周波数変 化量 A fを用いて擬似距離変化量 Δ pを推定するので、車両 90の移動/停止状態 のいずれにおいても擬似距離 P 'のスムージングを行うことができる。これにより、車 両 90の移動/停止状態のいずれにおいても擬似距離 pの精度、ひいては車両 90 の位置の精度を高めることができる。 [0046] When the vehicle 90 is stopped, it is based on the satellite position information in the same manner as in the first embodiment. The pseudo-range change Δp is estimated and the pseudo-range change Δp is estimated using the Doppler frequency change A f when the vehicle 90 is moving. The pseudo distance P ′ can be smoothed. As a result, the accuracy of the pseudo distance p and the accuracy of the position of the vehicle 90 can be improved in both the moving / stopping state of the vehicle 90.
[0047] また、車両 90の停止状態では、衛星位置情報に基づ!/、て推定した擬似距離変化 量 A pを用いて擬似距離 p 'のスムージングを行うことで、車両 90の移動状態及び 停止状態の双方でドップラー周波数変化量 Δ fに基づいて推定した擬似距離変化量 Δ pを用いて擬似距離 p,のスムージングを行う従来構成に比べて、車両 90の停止 状態における擬似距離 Pの精度、ひいては車両 90の位置の精度を高めることがで きる。これは、受信搬送波には、電離層の影響や自然界の存在する熱雑音、反射波 等の影響によりノイズが乗りやすぐかかるノイズが、受信した衛星信号に含まれる場 合には、ドップラー周波数変化量 A fの誤差が大きくなるからである。一方、衛星位置 情報は、力、かるノイズの影響を受けな!/、ので、衛星位置情報を用いた場合には擬似 距離変化量 Δ pを精度良く推定することができる。このように、本実施例 2では、車両 90の停止状態と移動状態とで、擬似距離変化量 Δ pの推定方法を切り替えることで 、車両 90の状態に応じて精度良く擬似距離変化量 Δ pを推定することでき、この結 果、擬似距離 Pの精度、ひいては車両 90の位置の精度を高めることができる。 [0047] When the vehicle 90 is stopped, smoothing of the pseudo distance p 'is performed using the pseudo distance change amount A p estimated based on the satellite position information! Compared to the conventional configuration in which the pseudorange p is smoothed using the pseudorange change Δp estimated based on the Doppler frequency change Δf in both stopped states, the accuracy of the pseudorange P when the vehicle 90 is stopped As a result, the accuracy of the position of the vehicle 90 can be increased. This is because the received carrier wave includes noise that is received or immediately applied due to the effects of the ionosphere, thermal noise in the natural world, reflected waves, etc., in the received carrier signal. This is because the error of A f becomes large. On the other hand, since the satellite position information is not affected by force or noise, the pseudorange change Δp can be accurately estimated when the satellite position information is used. As described above, in the second embodiment, the pseudo distance change amount Δ p is accurately changed according to the state of the vehicle 90 by switching the estimation method of the pseudo distance change amount Δ p between the stopped state and the moving state of the vehicle 90. As a result, it is possible to improve the accuracy of the pseudorange P, and hence the accuracy of the position of the vehicle 90.
[0048] 尚、本実施例 2においては、以下のような変形例が考えられる。 [0048] In the second embodiment, the following modifications can be considered.
[0049] 例えば、 GPS衛星 10と車両 90との間の相対速度 Δ νは、フィルタ 30にて算出さ れて、数 1で示したフィルタ式に導入されてもよい。 [0049] For example, the relative velocity Δν between the GPS satellite 10 and the vehicle 90 may be calculated by the filter 30 and introduced into the filter equation shown in Equation 1.
実施例 3 Example 3
[0050] 実施例 3は、上述の実施例 1に対して、車両 90が移動状態にあるときと停止状態に あるときとで、擬似距離変化量 Δ ρを異なる推定態様で推定する点が主に異なる。 以下では、実施例 3特有の構成について重点的に説明する。その他の構成につい ては、上述の実施例 1と同様であってよい。 [0050] The third embodiment is different from the first embodiment in that the pseudo-range change amount Δρ is estimated in different estimation modes when the vehicle 90 is in a moving state and when it is in a stopped state. Different. In the following, the configuration peculiar to the third embodiment will be described mainly. Other configurations may be the same as those in the first embodiment.
[0051] 図 7は、実施例 3に係る GPS受信機 3の要部構成を示す概略的なシステム構成図 である。図 7において、上述の実施例 1と同様の構成については同一の参照符号が
付されており、それらの説明は省略する。また、 GPS衛星 lC^からの衛星信号に関す る信号処理にっレ、て代表して説明する。 FIG. 7 is a schematic system configuration diagram showing the main configuration of the GPS receiver 3 according to the third embodiment. In FIG. 7, the same reference numerals are used for the same configurations as in the first embodiment. The description is omitted. In addition, the signal processing related to the satellite signal from the GPS satellite lC ^ will be described as a representative.
[0052] GPS受信機 3は、外部センサ 80が接続される。外部センサ 80は、 GPS受信機 3の 外部に設けられるセンサである力 GPS受信機 3に内蔵されてもよい。外部センサ 80 は、車両 90の移動量及び向き(方位)に関連する情報(以下、「車両情報」という)を 取得するセンサであり、複数種のセンサの組み合わせであってよい。例えば、外部セ ンサ 80は、車両 90の方位を検出する磁気インピーダンスセンサ(地磁気センサ)と、 車両 90の加速度を検出する加速度センサとの組み合わせであってよい。或いは、外 部センサ 80は、加速度センサと、車両 90のョ一方向の速度(角速度)を検出するョー レートセンサ(ジャイロセンサ)との組み合わせ(即ち、 INSセンサ)であってもよい。外 部センサ 80からの車両情報は、所定周期毎に、擬似距離変化量推定部 50Cに入力 される。 [0052] The external sensor 80 is connected to the GPS receiver 3. The external sensor 80 may be incorporated in the force GPS receiver 3 which is a sensor provided outside the GPS receiver 3. The external sensor 80 is a sensor that acquires information (hereinafter referred to as “vehicle information”) related to the movement amount and direction (azimuth) of the vehicle 90, and may be a combination of a plurality of types of sensors. For example, the external sensor 80 may be a combination of a magnetic impedance sensor (geomagnetic sensor) that detects the direction of the vehicle 90 and an acceleration sensor that detects the acceleration of the vehicle 90. Alternatively, the external sensor 80 may be a combination (that is, an INS sensor) of an acceleration sensor and a parallel sensor (gyro sensor) that detects the speed (angular speed) of the vehicle 90 in the single direction. The vehicle information from the external sensor 80 is input to the pseudo distance change amount estimation unit 50C at every predetermined period.
[0053] 図 8は、実施例 3に係る擬似距離変化量推定部 50Cによる擬似距離変化量推定処 理の一例の要部を示すフローチャートである。図 8に示す処理ルーチンは、所定周 期毎 (例えば、測位の演算周期毎)に繰り返し実行されてよい。図 8に示す処理のうち 、上述の実施例 1に係る図 4に示す処理と同様の処理については、同一のステップ 番号を付して説明を省略する。 FIG. 8 is a flowchart illustrating a main part of an example of the pseudo distance variation estimation process by the pseudo distance variation estimation unit 50C according to the third embodiment. The processing routine shown in FIG. 8 may be repeatedly executed every predetermined period (for example, every positioning calculation period). Of the processes shown in FIG. 8, the same processes as those shown in FIG. 4 according to Example 1 described above are denoted by the same step numbers and description thereof is omitted.
[0054] ステップ 113では、擬似距離変化量推定部 50Cは、外部センサ 80からの車両情報 に基づいて、車両 90 (正確には GPS受信機 3)の移動ベクトルを算出する。ここでは 、移動ベクトルは、前回周期と今回周期間での移動ベクトルとする。この際、例えば、 移動ベクトルの向きは、車両 90の向き(例えば地磁気センサからの情報)に基づいて 導出され、車両 90の移動量 (移動ベクトルの大きさ)は、加速度センサからの加速度 信号 (フィルタ後でもよい)を 2回積分することで導出されてよい。尚、移動ベクトルは 、外部センサ 80側で算出され、擬似距離変化量推定部 50Cにより取得されてもよい In step 113, the pseudo distance change amount estimation unit 50C calculates the movement vector of the vehicle 90 (more precisely, the GPS receiver 3) based on the vehicle information from the external sensor 80. Here, the movement vector is a movement vector between the previous cycle and the current cycle. At this time, for example, the direction of the movement vector is derived based on the direction of the vehicle 90 (for example, information from the geomagnetic sensor), and the amount of movement of the vehicle 90 (the magnitude of the movement vector) is calculated based on the acceleration signal ( It may be derived by integrating twice after filtering). The movement vector may be calculated on the external sensor 80 side and acquired by the pseudo distance change amount estimation unit 50C.
[0055] ステップ 115では、擬似距離変化量推定部 50Cは、衛星位置算出部 60からの衛 星位置情報に基づいて、 GPS衛星 10の移動ベクトルを算出すると共に、衛星位置 算出部 60からの衛星位置情報及び測位演算部 40からの車両 90の位置情報に基づ
いて、視線ベクトルを算出する。具体的には、 GPS衛星 1(^の移動ベクトルは、今回 周期で得られる GPS衛星 10の位置 (X (i)、Y (i)、Z (i))から、前回周期で得られ る GPS衛星 10の位置 (X (i— 1)、Y (i— 1)、Z (i—l))を差し引くことで導出され てもよい。また、視線ベクトルは、今回周期で得られる GPS衛星 lC^の位置 (X i Y (i)、 Z (i) )から、今回周期での車両 90の推定位置 (X (i) , Y (i) , Z (i) )[0055] In step 115, the pseudo-range variation estimation unit 50C calculates the movement vector of the GPS satellite 10 based on the satellite position information from the satellite position calculation unit 60 and the satellite from the satellite position calculation unit 60. Based on the position information and the position information of the vehicle 90 from the positioning calculation unit 40 And the line-of-sight vector is calculated. Specifically, the movement vector of GPS satellite 1 (^ is the GPS vector obtained in the previous cycle from the position (X (i), Y (i), Z (i)) of GPS satellite 10 obtained in this cycle. It may be derived by subtracting the position of satellite 10 (X (i-1), Y (i-1), Z (i-1)), and the line-of-sight vector is the GPS satellite lC obtained in this cycle. From the position of ^ (X i Y (i), Z (i)), the estimated position of the vehicle 90 in this cycle (X (i), Y (i), Z (i))
1 1 u推定 u推定 u推定 を差し引くことで導出されてもよい。推定位置 (x ω,γ ω, ζ ω)は、前 推定 推定 推定 1 1 u-estimation u-estimation u-estimation may be subtracted. Estimated position (x ω, γ ω, ζ ω)
回周期で得られる車両 90の位置 (X (i-1), Y (i—l), Z (i— 1))又は同様の推定 位置 (X (i-1), Y (i-1), Z (i 1))と、前回周期から今回周期に至るま 推定 推定 推定 Vehicle 90 position (X (i-1), Y (i-l), Z (i--1)) or similar estimated position (X (i-1), Y (i-1)) , Z (i 1)) and estimate from previous cycle to current cycle Estimate Estimate
での車両 90の移動ベクトル(上記のステップ 113の算出結果)に基づいて推定され てよい。 It may be estimated based on the movement vector of the vehicle 90 at (the calculation result of step 113 above).
[0056] 尚、 GPS衛星 10の移動ベクトルは、衛星位置算出部 60にて算出されてもよい。ま た、ステップ 100, 113、 115の処理順序は任意であってもよい。 Note that the movement vector of the GPS satellite 10 may be calculated by the satellite position calculation unit 60. Further, the processing order of steps 100, 113, and 115 may be arbitrary.
[0057] ステップ 160では、擬似距離変化量推定部 50Cは、外部センサ 80からの車両情報 と衛星位置算出部 60からの衛星位置情報に基づいて、擬似距離変化量 Δ ρを推定 する。具体的には、擬似距離変化量推定部 50Cは、上記のステップ 113で得られる 車両 90の移動ベクトルと、上記のステップ 115から得られる GPS衛星 10の移動べク トルと視線ベクトルとを用いて、擬似距離変化量 Δ ρを推定する。この場合、車両 90 の移動ベクトルと GPS衛星 10の移動ベクトルとを用いて、車両 90を基準とした GPS 衛星 10の相対移動ベクトルを求め、当該相対移動ベクトルと視線ベクトルとの内積 を擬似距離変化量 Δ ρとして算出してよい。或いは、擬似距離変化量推定部 50Αは 、今回周期での視線ベクトルの大きさ L(i)から前回周期での視線ベクトルの大きさ L( i— 1)を差し引いて得られる差分値(=L (i)— L (i— 1) )を、擬似距離変化量 Δ pと して推定してもよい。この場合、今回周期での視線ベクトルの大きさ L(i)は、今回周 期で得られる GPS衛星 10の位置 (X (i)、Y (i)、Z (i))から、今回周期での車両 9 0の推定位置 (X (i), Y (i), Z (i))を差し引いて得られるベクトルの大きさ 推定 推定 推定 In step 160, the pseudo distance change estimation unit 50C estimates the pseudo distance change Δρ based on the vehicle information from the external sensor 80 and the satellite position information from the satellite position calculation unit 60. Specifically, the pseudo distance change amount estimation unit 50C uses the movement vector of the vehicle 90 obtained in step 113 above, and the movement vector and line-of-sight vector of the GPS satellite 10 obtained from step 115 above. Then, the pseudo-range change amount Δρ is estimated. In this case, the movement vector of the vehicle 90 and the movement vector of the GPS satellite 10 are used to obtain the relative movement vector of the GPS satellite 10 with respect to the vehicle 90, and the inner product of the relative movement vector and the line-of-sight vector is changed by the pseudorange change. The quantity Δρ may be calculated. Alternatively, the pseudo distance change amount estimation unit 50Α calculates a difference value (= L) obtained by subtracting the line-of-sight vector size L (i−1) in the previous cycle from the line-of-sight vector size L (i) in the current cycle. (i) —L (i−1)) may be estimated as the pseudorange change Δp. In this case, the magnitude L (i) of the line-of-sight vector in this cycle is calculated from the position (X (i), Y (i), Z (i)) of the GPS satellite 10 obtained in this cycle. The size of the vector obtained by subtracting the estimated position (X (i), Y (i), Z (i)) of the vehicle 90 is estimated Estimated Estimated
を求めることで、導出されてよい。同様に、前回周期での視線ベクトルの大きさ L(i 1)は、前回周期で得られる GPS衛星 10の位置 (X (i-1), Y (i—l)、Z (i—l)) から、前回周期での車両 90の推定位置 (X (i-1), Y (i-1), Z (i—l)) u推定 u推定 U推定
を差し引いて得られるベクトルの大きさを求めることで、導出されてよい。このようにし て推定された擬似距離変化量 Δ pは、上述の如くフィルタ 30に入力され、上述の式 1の Δνの時間積分の項に代入されることにより、擬似距離 ρ,のスムージングに利用 される。 May be derived. Similarly, the magnitude L (i 1) of the line-of-sight vector in the previous cycle is the position of the GPS satellite 10 obtained in the previous cycle (X (i-1), Y (i-l), Z (i-l) ) From the estimated position of vehicle 90 in the previous cycle (X (i-1), Y (i-1), Z (i-l)) u estimation u estimation U estimation May be derived by obtaining the magnitude of the vector obtained by subtracting. The pseudo-range variation Δp estimated in this way is input to the filter 30 as described above, and is used for smoothing the pseudo-range ρ, by substituting it into the time integral term of Δν in Equation 1 above. Is done.
[0058] 以上説明した実施例 3による構成によれば、とりわけ、以下のような優れた効果が奏 される。 [0058] According to the configuration of the third embodiment described above, the following excellent effects can be obtained.
[0059] 車両 90の停止状態では、上述の実施例 1と同様の方法で、衛星位置情報に基づ いて擬似距離変化量 Δ Pを推定し、車両 90の移動状態では、外部センサ 80からの 車両情報等を用いて擬似距離変化量 Δ ρを推定するので、車両 90の移動/停止 状態のいずれにおいても擬似距離 ρ 'のスムージングを行うことができる。これによりThe stopped state of the [0059] vehicle 90, in the same manner as in Example 1 above, estimates the pseudorange change amount delta P and based on the satellite position information, the moving state of the vehicle 90, from the external sensor 80 Since the pseudo distance change amount Δρ is estimated using vehicle information or the like, the pseudo distance ρ ′ can be smoothed in any of the movement / stop states of the vehicle 90. This
、車両 90の移動/停止状態のいずれにおいても擬似距離 ρの精度、ひいては車両 90の位置の精度を高めることができる。 Therefore, the accuracy of the pseudo distance ρ and the accuracy of the position of the vehicle 90 can be improved in both the moving / stopping state of the vehicle 90.
[0060] また、上述の如ぐ車両 90の移動状態における擬似距離変化量 Δ ρを、外部セン サ 80からの車両情報等に基づいて推定するので、擬似距離 ρ 'のキヤリアスムージ ングを行う際に必要なドップラー周波数変化量を導出する必要がなくなる。従って、 衛星信号の搬送波位相を測定する機能を省 V、た安価な GPS受信機 3を用いた場合 であっても、車両 90の移動状態において擬似距離 ρ,のスムージングを行うことがで きる。 [0060] Further, since the pseudo distance change Δρ in the moving state of the vehicle 90 as described above is estimated based on vehicle information from the external sensor 80, etc., when carrying out the carrier smoothing of the pseudo distance ρ '. It is not necessary to derive the amount of change in Doppler frequency necessary for. Therefore, even when the inexpensive GPS receiver 3 that saves the function of measuring the carrier wave phase of the satellite signal is used, the pseudorange ρ can be smoothed in the moving state of the vehicle 90.
[0061] また、上述の実施例 2と同様、車両 90の停止状態と移動状態とで、擬似距離変化 量 Δ ρの推定方法を切り替えることで、車両 90の状態に応じて精度良く擬似距離変 化量 Δ Pを推定することでき、この結果、擬似距離 ρの精度、ひいては車両 90の位 置の精度を高めることができる。 [0061] Further, similarly to the above-described second embodiment, the pseudo-range change can be accurately changed according to the state of the vehicle 90 by switching the estimation method of the pseudo-range change amount Δρ between the stopped state and the moving state of the vehicle 90. We can estimate the reduction amount delta P, As a result, the accuracy of the pseudorange [rho, can be enhanced and thus the accuracy of the position of the vehicle 90.
[0062] 以上、本発明の好ましい実施例について詳説したが、本発明は、上述した実施例 に制限されることはなぐ本発明の範囲を逸脱することなぐ上述した実施例に種々の 変形及び置換を加えることができる。 The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions may be made to the above-described embodiments without departing from the scope of the present invention. Can be added.
[0063] 例えば、上述の実施例では、 C/Aコードを用いて擬似距離 ρ,を導出している力 本発明は、 L1波の Ρコード及び/又は L2波の Ρコードに基づいて、同様に、 GPS衛 星 10に対する擬似距離 ρ 'を算出する構成にも適用可能である。尚、 Ρコードの場合
、 Wコードで暗号化されているので、 Pコード同期を行う際に、クロス相関方式を利用 した DLLにより、 Pコードを取り出すこととしてよい。 Pコードに基づく擬似距離 p, は [0063] For example, in the above-described embodiment, the force for deriving the pseudorange ρ using the C / A code. The present invention is based on the L1 wave Ρ code and / or the L2 wave Ρ code. In addition, the present invention can be applied to a configuration for calculating the pseudorange ρ ′ for the GPS satellite 10. In case of Ρ code Because it is encrypted with the W code, when performing P code synchronization, the P code may be extracted by a DLL using the cross correlation method. Pseudorange p, based on P code,
P P
、 GPS衛星 10で Pコードが 0ビット目であるとして Pコードの Mビット目が車両 90に Assuming that the P code is the 0th bit in the GPS satellite 10, the M bit of the P code is
1 P て受信されている力、を計測することで、 =M X 30として求めること力 Sできる。 By measuring the force received at 1 P, the force S can be obtained as = M X 30.
P P P P
[0064] また、上述の実施例では、 GPSに本発明が適用された例を示した力 本発明は、 G PS以外の衛星システム、例えばガリレオ等の他の GNSS (Global Navigation Satellite System)にも適用可能である。 [0064] Further, in the above-described embodiments, the power of the present invention applied to GPS is shown. The present invention is applied to satellite systems other than GPS, for example, other GNSS (Global Navigation Satellite System) such as Galileo. Applicable.
[0065] また、上述の実施例では、移動体位置測位装置が GPS受信機 1 , 2, 3により実現 されているが、移動体位置測位装置は、 GPS受信機 1 , 2, 3とそれに接続される他 の電子部品とにより協働して実現されてもよい。 [0065] In the above-described embodiment, the mobile body positioning device is realized by the GPS receivers 1, 2, 3; however, the mobile body positioning device is connected to the GPS receivers 1, 2, 3, and the GPS receivers 1, 2, 3 It may be realized in cooperation with other electronic components.
[0066] また、上述の実施例 2と実施例 3とは、状況に応じて適切に組み合わせることも可能 である。例えば、車両 90が移動状態にある状況下で、電離層の活動が活発のとき( 屈折誤差の増大が生じやす!/、とき)や、市街地に車両 90が存在するとき(電波遮断 や反射波の影響を受けて誤差が出やすい環境下に車両 90が存在するとき)等のよう な、電波環境が悪いときには、上述の実施例 3におけるステップ 160の処理により擬 似距離変化量 Δ pを推定し、逆に電波環境が良好な場合には、上述の実施例 2に おけるステップ 150の処理により擬似距離変化量 Δ pを推定することとしてもよい。 [0066] Also, the above-described second and third embodiments can be appropriately combined depending on the situation. For example, when the vehicle 90 is in a moving state, when the ionospheric activity is active (a refraction error is likely to increase! /), Or when the vehicle 90 is present in an urban area (such as blocking radio waves or reflected waves) When the radio wave environment is poor, such as when the vehicle 90 is present in an environment where error is likely to occur, the pseudo distance change Δp is estimated by the processing of step 160 in the above-described third embodiment. On the other hand, when the radio wave environment is good, the pseudo-range change Δp may be estimated by the process of step 150 in the second embodiment.
[0067] また、上述の実施例 3において、車両 90の移動量 (移動ベクトルの大きさ)は、加速 度センサからの加速度に代えて、車輪速センサの出力信号のような車速を表すパラ メータを用いて導出されてもょレ、。 In the third embodiment, the movement amount (the magnitude of the movement vector) of the vehicle 90 is a parameter that represents the vehicle speed, such as an output signal of the wheel speed sensor, instead of the acceleration from the acceleration sensor. Derived using
[0068] 尚、本国際出願は、 2006年 11月 27日に出願した日本国特許出願 2006— 3188 47号に基づく優先権を主張するものであり、その全内容は本国際出願にここでの参 照により援用されるものとする。
[0068] This international application claims priority based on Japanese Patent Application 2006-318847 filed on November 27, 2006, the entire contents of which are hereby incorporated into this international application. It shall be incorporated by reference.
Claims
[1] 受信した衛星信号に基づいて衛星と移動体の間の擬似距離を算出する擬似距離 算出手段と、 [1] a pseudo-range calculating means for calculating a pseudo-range between the satellite and the moving object based on the received satellite signal;
移動体が停止したか否かを判定する停止判定手段と、 Stop determination means for determining whether or not the moving body has stopped;
前記衛星信号の発信元の衛星の位置を算出する衛星位置算出手段と、 擬似距離変化量を推定する擬似距離変化量推定手段と、 Satellite position calculating means for calculating the position of the satellite from which the satellite signal is transmitted; pseudo distance change estimating means for estimating the pseudo distance change;
前記擬似距離算出手段により算出された擬似距離と、前記擬似距離変化量推定 手段により推定された擬似距離変化量とに基づ V、て、移動体の位置を測位する測位 手段とを備え、 A positioning means for positioning the position of the moving body based on the pseudo distance calculated by the pseudo distance calculating means and the pseudo distance change estimated by the pseudo distance change estimating means;
前記擬似距離変化量推定手段は、前記停止判定手段により移動体の停止が判定 された場合に、前記衛星位置算出手段により算出される衛星の位置の変化履歴を用 いて、前記擬似距離変化量を推定することを特徴とする、移動体位置測位装置。 The pseudo distance change estimation means uses the satellite position change history calculated by the satellite position calculation means to calculate the pseudo distance change when the stop determination means determines that the moving body is stopped. A mobile object positioning apparatus characterized by estimating.
[2] 前記擬似距離変化量推定手段は、前記停止判定手段により移動体が停止してい ないと判定された場合に、前記移動体の移動ベクトルを用いて、前記擬似距離変化 量を推定する、請求項 1に記載の移動体位置測位装置。 [2] The pseudo distance change amount estimation means estimates the pseudo distance change amount using a movement vector of the moving body when the stop determination means determines that the moving body is not stopped. The mobile body positioning device according to claim 1.
[3] 前記擬似距離変化量推定手段は、前記停止判定手段により移動体が停止してい ないと判定された場合に、前記移動体の移動ベクトルと、前記衛星位置算出手段に より算出される衛星の位置の変化履歴に基づいて導出される衛星の移動ベクトルと を用いて、前記擬似距離変化量を推定する、請求項 2に記載の移動体位置測位装 置。 [3] The pseudo-range change amount estimating means is a satellite calculated by the movement vector of the moving object and the satellite position calculating means when the stop determining means determines that the moving object is not stopped. The mobile position measurement apparatus according to claim 2, wherein the pseudo-range change amount is estimated using a movement vector of a satellite derived based on a position change history of.
[4] 前記擬似距離変化量推定手段は、前記移動体の移動 タトルと、前記衛星の移動 ベクトルとを用いて、移動体を基準とした前記衛星の相対移動ベクトルを算出すると 共に、前記衛星位置算出手段により算出される衛星の位置と、前記測位手段により 測位される移動体の位置とを用いて、移動体に対する衛星の位置ベクトルを算出し、 該算出した相対移動ベクトルと位置ベクトルとの内積を擬似距離変化量として推定す る、請求項 3に記載の移動体位置測位装置。 [4] The pseudo-distance change amount estimation means calculates a relative movement vector of the satellite with reference to the moving body, using the movement tuttle of the moving body and the movement vector of the satellite, and the position of the satellite Using the position of the satellite calculated by the calculation means and the position of the moving body measured by the positioning means, the position vector of the satellite with respect to the moving body is calculated, and the inner product of the calculated relative movement vector and the position vector 4. The mobile body positioning device according to claim 3, wherein is estimated as a pseudo-range change amount.
[5] 前記移動体の移動ベクトルは、移動体に搭載されたセンサにより検出される移動体 の姿勢と移動量に関連する情報、又は、衛星信号の搬送波のドップラー周波数変化
量に基づいて算出される、請求項 2〜4のいずれかに記載の移動体位置測位装置。 [5] The movement vector of the moving object is information related to the attitude and movement amount of the moving object detected by a sensor mounted on the moving object, or a change in Doppler frequency of the carrier wave of the satellite signal. The mobile body positioning device according to any one of claims 2 to 4, wherein the mobile body positioning device is calculated based on a quantity.
[6] 前記擬似距離変化量推定手段は、前記停止判定手段により移動体の停止が判定 された場合に、前記衛星位置算出手段により算出される衛星の位置の変化履歴に 基づいて導出される衛星の移動ベクトルと、前記衛星位置算出手段により算出される 衛星の位置及び前記測位手段により測位される移動体の位置に基づいて導出され る移動体に対する衛星の位置ベクトルとの内積を、前記擬似距離変化量として推定 する、請求項;!〜 5のいずれかに記載の移動体位置測位装置。 [6] The pseudo-range change amount estimation means is a satellite derived based on a satellite position change history calculated by the satellite position calculation means when the stop determination means determines that the moving body is stopped. The pseudo-range is the inner product of the movement vector of the satellite and the position vector of the satellite with respect to the moving object derived based on the position of the satellite calculated by the satellite position calculating means and the position of the moving object determined by the positioning means. The moving body position measuring apparatus according to claim 5, wherein the moving body position measuring apparatus estimates the amount of change.
[7] 前記擬似距離変化量推定手段により推定された擬似距離変化量を用いて、前記 擬似距離算出手段により算出された擬似距離にフィルタをかけるフィルタ手段を更に 備え、 [7] The apparatus further comprises filter means for filtering the pseudo distance calculated by the pseudo distance calculation means using the pseudo distance change estimated by the pseudo distance change estimation means,
前記測位手段は、前記フィルタ手段によりフィルタがかけられた擬似距離に基づレ、 て、移動体の位置を測位する、請求項;!〜 6のいずれかに記載の移動体位置測位装 置。
7. The moving body position measuring device according to claim 6, wherein the positioning means measures the position of the moving body based on the pseudo distance filtered by the filter means.
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JPH042913A (en) * | 1990-04-20 | 1992-01-07 | Mitsubishi Electric Corp | Navigator for spacecraft |
JPH0763838A (en) * | 1993-08-26 | 1995-03-10 | Japan Radio Co Ltd | Gps receiver |
JPH07198821A (en) * | 1994-01-06 | 1995-08-01 | Japan Radio Co Ltd | Gps receivr and its positoning method |
JPH10111137A (en) * | 1996-10-07 | 1998-04-28 | Hitachi Ltd | Gps navigator |
JPH11118903A (en) * | 1997-10-16 | 1999-04-30 | Matsushita Electric Ind Co Ltd | Position detecting device |
JP2006242706A (en) * | 2005-03-02 | 2006-09-14 | Matsushita Electric Ind Co Ltd | Positioning system |
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JPH042913A (en) * | 1990-04-20 | 1992-01-07 | Mitsubishi Electric Corp | Navigator for spacecraft |
JPH0763838A (en) * | 1993-08-26 | 1995-03-10 | Japan Radio Co Ltd | Gps receiver |
JPH07198821A (en) * | 1994-01-06 | 1995-08-01 | Japan Radio Co Ltd | Gps receivr and its positoning method |
JPH10111137A (en) * | 1996-10-07 | 1998-04-28 | Hitachi Ltd | Gps navigator |
JPH11118903A (en) * | 1997-10-16 | 1999-04-30 | Matsushita Electric Ind Co Ltd | Position detecting device |
JP2006242706A (en) * | 2005-03-02 | 2006-09-14 | Matsushita Electric Ind Co Ltd | Positioning system |
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