JP2008298443A - Multipath detection device, positioning device, attitude azimuth orientation device, multipath detection method, and multipath detection program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To orient highly accurately a position and an attitude angle based on observation information of a carrier wave with no influence by a multipath. <P>SOLUTION: A phase difference calculation part 130 calculates a single difference or a double difference of a carrier wave phase between each GPS antenna 951 relative to each carrier wave from each GPS satellite, based on each carrier wave phase showing a distance between each GPS satellite and each GPS antenna 951 by the number of carrier waves. A LOS vector calculation part 140 calculates a LOS vector to each GPS satellite based on a navigation message and a single positioning result. A baseline length calculation part 150 calculates the baseline length between each GPS antenna 951 based on the single difference or the double difference of the carrier wave phase and the LOS vector. A multipath determination part 160 determines whether or not a multipath wave is included in each carrier wave used for calculating an observation baseline length by comparing the calculated observation baseline length with a known baseline length. A position attitude azimuth orientation part 120 orients a position attitude based on observation information of the carrier wave which is not a multipath wave. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to, for example, a multipath detection device, a multipath detection method, a multipath detection program, and a positioning device / attitude orientation determination device having a multipath removal function using a plurality of GPS (Global Positioning System) receivers. It is.

GPS measures the propagation time of positioning signals (carrier waves, radio waves) from satellites that have arrived at the antenna, observes the distance from the satellite of the antenna, and calculates the position of the satellite from the navigation message indicated by the positioning signal. It is a system that measures the position of the antenna by the principle of triangulation based on this information. In GPS, multipath, which is an event that arrives at an antenna after being reflected by a building or the like rather than directly from a satellite, causes a delay in the propagation time of the positioning signal. Become.
As a method for suppressing multipath, there are a ground plane, a choke ring, a radio wave absorber, an antenna and a correlator. However, it is difficult to detect a multipath completely with only one means, and it is ideal to take measures as much as possible.
The GPS can also be used for attitude determination, and in this case, a plurality of antennas are necessarily required.
JP-A-11-94573

  An object of the present invention is, for example, to determine a position and an attitude angle with high accuracy based on observation information of a carrier wave that is not affected by multipath.

  The multipath detection apparatus according to the present invention is configured such that a plurality of GPS (Global Positioning System) antennas are transmitted from each GPS satellite and received by each GPS antenna in a moving body in which a relative position between the GPS antennas is fixed. Is a multipath detection device that detects whether or not a multipath wave is included therein, and receives carrier phase information indicating the distance between each GPS satellite and each GPS antenna in terms of the number of carrier waves. Based on the information, a phase difference calculation unit that calculates a carrier phase difference between the GPS antennas with the same GPS satellite using a CPU (Central Processing Unit), and a carrier phase between the GPS antennas calculated by the phase difference calculation unit Specific GPS antennas identified by difference and any method LOS (Line Of Light) vector indicating the direction from the GPS to a specific GPS satellite is input, and the baseline length indicating the distance between the GPS antennas is observed based on the input carrier phase difference and the input LOS vector. A baseline length calculation unit that is calculated using a CPU, a known baseline length that indicates a distance between GPS antennas that is calculated in advance, and an observation baseline length that is calculated by the baseline length calculation unit are compared using the CPU. A multipath determination unit that determines that a multipath wave is included in each carrier wave used for calculation of the observation baseline length when the length differs from a known baseline length by a predetermined threshold or more. And

  According to the present invention, for example, it is possible to specify a carrier wave that is not affected by multipath, and therefore it is possible to determine the position and attitude angle with high accuracy based on observation information of a carrier wave that is not affected by multipath.

Embodiment 1 FIG.
FIG. 1 is a schematic diagram of a configuration of a position and orientation determination system 100 according to the first embodiment.
The position / orientation locating system 100 includes a position (for example, three-dimensional coordinates) and a posture angle (for example, roll [rotation angle], pitch) of a moving body (for example, a vehicle) in which a platform 954 as shown in FIG. (Elevation angle) and yaw [azimuth angle] in three axis directions).
A plurality of GPS antennas 951 and a gyro 953 that measures angular velocities in three axial directions are fixedly disposed on the platform 954. That is, the relative positional relationship between the plurality of GPS antennas 951 is restricted and does not change.

  The position / orientation locating system 100 is based on the relationship with the length of the baseline vector between the GPS antennas 951 (hereinafter referred to as the baseline length) that is fixed even if the moving body moves due to the relative positional relationship being constrained. Then, it is determined whether the carrier wave of the positioning signal reaching the GPS antenna 951 from the GPS satellite is a multipath wave. Then, the position / orientation determination system 100 determines the position and the attitude angle of the moving body based on the GPS observation information obtained by the GPS receiver 952 for the carrier wave determined not to be a multipath wave.

Here, the base line vector is a vector indicating the distance and direction between two points, for example, the vector from the master station to the slave station (1) or the vector from the master station to the slave station (2) in FIG. It is.
In addition, the multipath wave is a wave in which a carrier wave transmitted from a GPS satellite arrives at the GPS antenna 951 after being reflected directly on a feature such as a building, and the multipath wave from the GPS satellite to the GPS antenna 951. Since the propagation time includes a delay time, the positioning result calculated based on the propagation time of the multipath wave includes a large error. Therefore, the position / orientation locating apparatus 101 determines a multipath wave, and determines the position and attitude angle of the moving body based on observation information of a carrier other than the multipath wave. Hereinafter, a carrier wave that is a non-multipath wave reflected by a feature and directly reaches the GPS antenna 951 from a GPS satellite is referred to as a direct wave.

  Further, as long as the relative positional relationship between the plurality of GPS antennas 951 can be maintained, the platform 954 is not necessarily provided as shown in FIG.

Furthermore, although the position and orientation determination system 100 shown in FIG. 1 includes three GPS antennas 951 and GPS receivers 952 on the platform 954, the number may be two or four or more.
For example, if at least two of the three GPS receivers 952 can receive a carrier wave from a GPS satellite via the GPS antenna 951, the position and orientation locator 101 can determine multipath waves, and the three-dimensional coordinates of the moving object can be obtained. Can be identified. Further, one base line vector is determined based on observation information of the carrier waves that have reached the two GPS antennas 951, and the azimuth angle and elevation angle of the moving body corresponding to the base line vector are determined based on the one base line vector. Further, another base line vector is determined based on the observation information of the carrier wave that has reached the other GPS antenna 951, and the rotation angle of the moving body is determined by the two base line vectors.

FIG. 2 is a hardware configuration diagram of the position and orientation determination system 100 according to the first embodiment.
The position and orientation determination system 100 includes a plurality of GPS antennas 951, a GPS receiver 952 connected to each GPS antenna 951, and three axial directions (roll angle [rotation angle], pitch angle [elevation angle], and yaw angle [azimuth angle]). A gyro 953 for measuring the angular velocity of the head and a position / orientation locator 101.
The gyro 953 measures and outputs an angular velocity (also referred to as an angular rate) in three axial directions (roll angle, pitch angle, and yaw angle).
Each GPS receiver 952 is a navigation message indicated by the phase information of the carrier wave and the positioning signal propagated by the carrier wave with respect to the carrier wave of the positioning signal (L1, L2, L5, etc.) arriving from the GPS satellite to the GPS antenna 951 to which it is connected. (Satellite orbit information), GPS antenna 951 calculated based on carrier wave propagation time and GPS satellite distance (pseudo distance), GPS antenna 951 position calculated based on pseudo distance (single positioning result), etc. Output as information.

The phase information of the carrier wave output as GPS observation information by the GPS receiver 952 indicates the number of carrier waves corresponding to the propagation time of the carrier wave if the integer value bias included therein is removed by some method, and indicates the propagation distance of the carrier wave. To express. The number of carrier waves indicated by the phase information is represented by an “integer” part and a “decimal part”, and the “decimal part” corresponds to the phase of the carrier wave when reaching the GPS antenna 951.
Hereinafter, the “integer” portion of the carrier indicated by the phase information is referred to as “number of carriers”, the “decimal” portion of the carrier indicated by the phase information is referred to as “phase”, and the number of carriers indicated by the phase information (“integer” + “decimal”) ) Is “carrier phase”.

The position and orientation determination apparatus 101 includes a CPU 911 (Central Processing Unit) that executes a program. The CPU 911 is connected to a storage device 920 including storage devices such as a RAM, a ROM, and a magnetic disk device via a bus.
The storage device 920 stores an operating system (OS) 921, a program group 923, and a file group 924. The program group 923 is executed by the CPU 911 and the OS 921.
The program group 923 stores a program for executing a function described as “˜unit” in the description of the embodiment. The program is read and executed by the CPU 911.
Various types of data are stored in the file group 924. In the description of the embodiment, data described as “to information”, data indicating a determination result / calculation result when a function described as “to part” is executed, “ Data to be transferred between programs that execute the function described as “˜part” is stored as “˜file”. For example, the GPS observation information acquired from the GPS receiver 952, the determination result as to whether or not the carrier wave is a multipath wave, and information such as the position / attitude angle of the determined moving body are stored as “˜file”.
Further, in the description of the embodiments, the arrows in the flowcharts and the configuration diagrams mainly indicate data input / output, and the data for the data input / output is stored in the storage device 920 or a signal line or other transmission medium. It is transmitted by.
In addition, what is described as “˜unit” in the description of the embodiment may be realized by firmware stored in the ROM. Alternatively, it may be implemented by software alone, hardware alone, a combination of software and hardware, or a combination of firmware.

FIG. 3 is a functional configuration diagram of the position and orientation determination apparatus 101 according to the first embodiment.
A functional configuration of the position / orientation locating apparatus 101 included in the position / orientation locating system 100 according to Embodiment 1 will be described below with reference to FIG.

  In FIG. 3, a position / orientation locating device 101 (multipath detection device, positioning device, orientation / orientation locating device) uses a CPU to detect whether or not an observed carrier wave is a multipath wave. And a position / orientation orientation determination unit 120 (positioning unit, attitude determination unit) for determining the position and orientation angle of the moving body using a CPU based on observation information of a carrier wave that is not a multipath wave, and the position and orientation angle of the moving body, GPS An orientation storage unit that stores location information and information used for orientation, such as GPS observation information of the receiver 952, a measured value (rate) of the gyro 953, a known baseline length between GPS antennas 951, which will be described later, and the like. 190.

  The multipath detection unit 110 includes a phase difference calculation unit 130, a LOS vector calculation unit 140, a baseline length calculation unit 150, and a multipath determination unit 160.

  The phase difference calculation unit 130 inputs carrier phase information indicating the distance between each GPS satellite and each GPS antenna by the number of carriers, and based on the inputted carrier phase information, the same GPS satellites between the GPS antennas are the same. A difference in carrier phase at time (single difference or double difference in carrier phase described later) is calculated using a CPU.

  The LOS vector calculation unit 140 inputs a navigation message indicating the position of each GPS satellite propagated by the carrier wave and positioning information indicating the position of the GPS antenna measured based on the carrier wave, and each of the navigation messages indicated by the input navigation message indicates Based on the position of the GPS satellite and the position of each GPS antenna indicated by the input positioning information, a LOS (Line Of Light) vector indicating the direction from the GPS antenna to the GPS satellite is calculated using the CPU.

  Baseline length calculation unit 150 receives the difference in carrier phase between GPS antennas calculated by phase difference calculation unit 130 and the LOS vector indicating the direction from a specific GPS antenna specified by an arbitrary method to a specific GPS satellite. Then, based on the input carrier phase difference and the input LOS vector, the base line length indicating the distance between the GPS antennas is calculated using the CPU as the observation base line length.

  The multipath determination unit 160 compares the known baseline length indicating the distance between the GPS antennas calculated in advance with the observation baseline length calculated by the baseline length calculation unit 150 using the CPU, and the observation baseline length is calculated from the known baseline length. When the difference is equal to or greater than a predetermined threshold, it is determined that a multipath wave is included in each carrier wave used for calculating the observation baseline length.

FIG. 4 is a flowchart showing the position / orientation locating method according to the first embodiment.
A position and orientation determination method (an example of a multipath detection method, a positioning method, and an orientation and orientation determination method) of the position and orientation determination system 100 according to the first embodiment will be described below with reference to FIG.

<S110: GPS observation processing>
First, each GPS receiver 952 receives a positioning signal carrier wave from a GPS satellite that has reached a connected GPS antenna 951, and outputs GPS observation information for the received positioning signal carrier wave.
The GPS observation information includes, for example, carrier phase information (carrier phase), a navigation message (satellite orbit information) indicated by a positioning signal propagated by the carrier, and a distance between the GPS antenna 951 and the GPS satellite based on the propagation time of the carrier ( Pseudo distance), the position of the GPS antenna 951 based on the pseudo distance (single positioning result), and the like.

<S120: Multipath detection processing>
Next, the multipath detection unit 110 of the position / orientation locating apparatus 101 calculates the difference in carrier phase of the carrier wave from the same GPS satellite between the GPS antennas 951 based on the GPS observation information (single difference or double difference in distance) from the CPU. Based on the calculated carrier phase difference and the known baseline length between the GPS antennas 951, which is a fixed length, a carrier wave that is a multipath wave is detected using a CPU.
For example, the multipath detection unit 110 uses the difference between the carrier wave phases and the LOS (Line Of Light) vector indicating the direction from the GPS antenna 951 that has received the carrier to the GPS satellite that has transmitted the carrier. Calculate the baseline length as the observed baseline length, compare the observed baseline length with the known baseline length, and if the observed baseline length differs from the known baseline length by a predetermined threshold or more, the carrier used to calculate the observed baseline length is a multipath wave Is determined.
Further, for example, the multipath detection unit 110 calculates a distance difference between the GPS antennas 951 and the same GPS satellite as the estimated distance difference based on the known base line length, the attitude angle of the moving body based on the measured value of the gyro 953, and the LOS vector. When the observation distance difference indicated by the difference in carrier phase is different from the estimated distance difference by a predetermined threshold or more, the carrier corresponding to the observation distance difference is determined to be a multipath wave.
Details of the multipath detection process (S120) will be described later.

<S130: Position / Orientation Orientation Processing>
Then, the position / orientation orientation determination unit 120 of the position / orientation determination apparatus 101 determines the position and the attitude angle of the moving body based on GPS observation information of a carrier wave that is not a multipath wave.
For example, when there is no carrier determined to be a multipath wave, the position / orientation orientation determination unit 120 uses the single positioning result included in the GPS observation information as the position of the moving object.
In addition, for example, the position / orientation orientation determination unit 120 measures the position of the moving object based on pseudoranges or carrier phases for four or more carriers determined to be not multipath waves.
Further, for example, the position / orientation orientation determination unit 120 calculates two baseline vectors between the GPS receivers 952 based on the carrier phase of the carrier determined to be not a multipath wave, and the mobile object based on the calculated two baseline vectors The attitude angle of is calculated.
Further, for example, the position / orientation orientation determination unit 120 determines the mobile body-GPS based on the position of the mobile body calculated by the pseudorange or carrier phase of the carrier wave determined to be not a multipath wave and the dead reckoning and the position of the GPS satellite indicated by the navigation message. Based on the difference with the distance between the satellites (pseudo-range residual), the error of the position and posture angle of the moving object calculated by dead reckoning is estimated by Kalman filter processing, and the position and posture angle of the moving object calculated by dead reckoning are calculated. The position and posture angle of the moving body are determined by correcting based on the estimation error.
Details of the position / orientation orientation processing (S130) will be described later.

FIG. 5 is a flowchart showing the multipath detection process (S120) in the first embodiment.
The multipath detection process (S120) executed by the multipath detection unit 110 of the position and orientation determination apparatus 101 in the first embodiment will be described below with reference to FIG.
Each unit of the multipath detection unit 110 executes the following processes described with reference to FIG. 5 using the CPU.

<S210: Phase difference calculation process>
First, the phase difference calculation unit 130 receives the phase information (carrier phase) of the carrier included in the GPS observation information output from the GPS receiver 952, and based on the carrier phase indicated by the input phase information of the carrier, between the GPS antennas 951. The carrier phase difference (single distance difference, double difference) is calculated.

In the phase difference calculation process (S210), the phase difference calculation unit 130 calculates the single phase difference of the carrier wave phase when each GPS receiver 952 operates based on the same time information, and each GPS receiver 952 has a different time. When operating based on information, a double difference in carrier phase is calculated.
Here, the difference between the observation values of two GPS receivers 952 for one same GPS satellite (observation values for the carrier waves that have reached each of the two GPS antennas 951 from the same GPS satellite) is received by GPS. The single phase difference between the two aircraft 952 is the difference between the carrier phase transmitted from the same GPS satellite and observed by each of the two GPS receivers 952.
The difference between two single differences is called a double difference, and the double difference in carrier phase is the difference between the single differences in carrier phase obtained for different GPS satellites.

For example, in FIG. 6, when GPS observation is performed based on the same time information via two GPS antennas 951 located at points a and b, the phase difference calculation unit 130 determines the carrier wave transmitted from the GPS satellite i. The difference between the carrier phase observed via the GPS antenna 951 located at point a and the carrier phase observed via the GPS antenna 951 located at point b is calculated as a single difference in carrier phase.
In FIG. 6, the single difference in the carrier phase at points a and b for the carrier from the GPS satellite i is the distance ρ _a ⁱ between the GPS satellite i and the point a indicated by the carrier phase observed at the point _a , The difference between the GPS satellite i and the distance ρ _b ⁱ indicated by the carrier phase observed at the point b is expressed by the following formula 1.

  Similarly, the phase difference calculation unit 130 calculates a single difference in carrier phase for all GPS satellites for which carrier waves are observed by the two GPS antennas 951. For example, when the carrier wave from the GPS satellite i, the carrier wave from the GPS satellite j, and the carrier wave from the GPS satellite k are observed via both of the two GPS antennas 951, the phase difference calculation unit 130 determines whether the GPS satellite i and the GPS satellite A single difference in the carrier phase is calculated for each of the satellite j and the GPS satellite k.

Further, for example, in FIG. 6, when GPS observation is performed based on different time information via two GPS antennas 951 located at points a and b, the phase difference calculation unit 130 uses a carrier wave transmitted from a GPS satellite i. The single phase difference between the points a and b is calculated for the carrier wave, and the single phase difference between the points a and b is calculated for the carrier wave transmitted from the GPS satellite j. The difference of the single difference is calculated as the double difference of the carrier phase.
In FIG. 6, the double difference in the carrier phase at points a and b for the carrier from GPS satellite i and the carrier from GPS satellite j is the single difference in carrier phase for the carrier from GPS satellite i and GPS. The difference between the carrier phase from the satellite j and the single phase of the carrier phase is expressed by Equation 2 below.

  Similarly, the phase difference calculation unit 130 calculates the double difference in the carrier phase for all GPS satellites for which carrier waves are observed by the two GPS antennas 951. For example, when the carrier from the GPS satellite i, the carrier from the GPS satellite j, the carrier from the GPS satellite k, and the carrier from the GPS satellite l are observed via both of the two GPS antennas 951, the phase difference calculation unit 130 Is the difference in carrier phase for GPS satellite i and GPS satellite j, by taking the difference in carrier phase for GPS satellite i, GPS satellite j, and the difference in carrier phase for GPS satellite i. The double difference, the double difference of the carrier phase for the GPS satellite i and the GPS satellite k, and the double difference of the carrier phase for the GPS satellite i and the GPS satellite l are calculated.

  In the following, the phase difference calculation unit 130 calculates a single phase difference in the carrier phase when each GPS receiver 952 operates based on the same time information in the phase difference calculation process (S210), and each GPS receiver 952 The reason for calculating the double difference of the carrier phase when operating based on different time information will be described.

First, the carrier phase Φ ⁱ _a for the satellite i (one of the GPS satellites) observed by the receiver a (one of the GPS receivers 952) can be expressed by Equation 3 below.

In the above formula 1, the ionospheric delay _dion in the carrier phase observation is negative, contrary to that at the pseudorange calculated based on the C / A code indicated by the positioning signal, and apparently exceeds the speed of light. A typical amount of ionospheric delay d _ion is about 5 m near the zenith, and depends on the elevation angle (hereinafter referred to as the elevation angle of the satellite) at which the satellite is viewed from the antenna.
The tropospheric delay _d.sub.trop can be divided into a dry term and a wet term due to its nature. Dry terms account for 90 percent of the tropospheric delay d _trop but can be estimated stably accurately by appropriately measure for that. On the other hand, the wet term changes depending on the temperature, the atmospheric pressure, the humidity, and the elevation angle of the satellite. Tropospheric Delay _{d trop} spans the 5～25M, largely depends on the elevation angle of the satellite.
On the other hand, the observation error of the carrier phase is very small, the noise ε (Φ _γx ) of the receiver is usually 1% or less of the wavelength λ, and the carrier phase error is about 5 cm at L1.
The antenna phase center offset ε (Φ _ant ) is an offset amount of the phase center with respect to the geometric center of the antenna, and the amount varies depending on the antenna model, but is generally said to be 1 to 2 cm. ing. In the embodiment, between the GPS antennas 951 indicates an antenna phase center that is a phase center of a received carrier wave in the GPS antenna 951.

Here, for a common satellite, the difference between the carrier phase observation values obtained by two different receivers is called the single difference between the receivers. The clock error dt ⁱ can be canceled.
Equation 4 below shows the receiver-to-receiver single difference for Equation 3 representing the carrier phase.

In the receiver-to-receiver single difference represented by Equation 4 above, the clock error dt ^{i of} satellite ⁱ is canceled with respect to Equation 3 above.

Further, the double difference is a difference between single receivers for different satellites (for example, satellite i and satellite j), and the receiver a , B can cancel the clock error dT _ab .
Equation 5 for the double difference with respect to Equation 4 representing the single difference between the receivers is shown below.

  When taking the double difference, a single difference between the receivers is usually taken with the zenith satellite as the primary satellite, and a single difference between the receivers for the remaining plurality of slave satellites is taken. For example, when n satellites can be observed by two receivers in common, the double difference observation value is n-1.

In the double difference represented by the above equation 5, the clock errors (dt ⁱ , dT _a ) are canceled for both the satellite and the receiver with respect to the above equation 1.

Here, when used for applications such as attitude determination by GPS, since the two antennas are installed in the attitude determination object, the span of the two antennas is not so large, the orbit error of the satellite, the group delay due to the troposphere, and The effect of ionospheric delay is almost the same when observed by each receiver.
Therefore, the above equations 4 and 5 can be expressed as the following equations 6 and 7.

  In an attitude determination dedicated GPS receiver (GPS gyro) using a plurality of antennas, a multi-channel receiver having a common clock is often used. In this case, since there is no clock error between the receivers, a single difference with less noise than a double difference can be used, which is ideal. When using non-dedicated receivers whose clocks are not common, it is effective not only to cancel the clock error of the receiver, but also to take a double difference in order to cancel the difference in cable length.

  Therefore, in the phase difference calculation process (S210), the phase difference calculation unit 130 calculates a single phase difference of the carrier phase when each GPS receiver 952 operates based on the same time information, and each GPS receiver 952 has a different time. When operating based on information, a double difference in carrier phase is calculated.

Returning to FIG. 5, the description of the multipath detection process (S120) will be continued.
In the subsequent processing, the multipath detection unit 110 calculates a baseline vector between the GPS antennas 951 based on the carrier phase difference calculated in the phase difference calculation processing (S210), and calculates the length of the calculated baseline vector and the length of the baseline vector in advance. The measured baseline length is compared to determine whether the carrier wave is a multipath wave or a direct wave.
Hereinafter, description will be made assuming that three or more single phase differences or double differences of the carrier phase are calculated in the phase difference calculation process (S210). The number of single or double differences in the carrier phase indicates the number of GPS satellites on which the carrier was observed, and the single difference in the three carrier phases indicates that three GPS satellite carriers were observed. The double difference in phase indicates that four GPS satellite carriers were observed.

<S230: LOS vector calculation process>
The LOS vector calculation unit 140 calculates a LOS vector indicating the direction from the GPS antenna 951 that has received the carrier to the GPS satellite that has transmitted the carrier for the carrier for which the phase difference calculation unit 130 has calculated the carrier phase difference in S210. To do.
At this time, the LOS vector calculation unit 140 inputs observation information of the carrier wave observed by the GPS antenna 951 that is a target for calculating the LOS vector, and calculates a LOS vector based on the input observation information.

For example, in FIG. 6, when the phase difference calculation unit 130 calculates a single difference in carrier phase between two GPS antennas 951 located at points a and b for a carrier wave transmitted from a GPS satellite i, an LOS vector calculation unit 140 denotes a GPS antenna 951 positioned at point a based on the position a of the GPS antenna 951 indicated by the single positioning result included in the GPS observation information and the position of the GPS satellite i indicated by the navigation message included in the GPS observation information. A LOS vector e _a ⁱ indicating the direction to the GPS satellite i is calculated.
Further, for example, in FIG. 6, the phase difference calculation unit 130 determines the carrier phase of two GPS antennas 951 located at points a and b with respect to the carrier transmitted from the GPS satellite i and the carrier transmitted from the GPS satellite j. When the double difference is calculated, the LOS vector calculation unit 140 calculates the position a of the GPS antenna 951 indicated by the single positioning result included in the GPS observation information and the position of the GPS satellites i and j indicated by the navigation message included in the GPS observation information. LOS vector e _a ⁱ indicating the direction from GPS antenna 951 located at point a to GPS satellite i, and LOS vector e _a ^j indicating the direction from GPS antenna 951 located at point a to GPS satellite j, Is calculated.
Similarly, the LOS vector calculation unit 140 calculates the LOS vector for each GPS satellite for which the single phase difference or double difference of the carrier phase is calculated. For example, when the single phase difference of the carrier phase is calculated for three carriers, that is, the carrier from the GPS satellite i, the carrier from the GPS satellite j, and the carrier from the GPS satellite k, the LOS vector calculation unit 140 is positioned at point a. The LOS vectors e _a ⁱ , e _a ⁱ and e _a ⁱ from the GPS antenna 951 to the GPS satellites i, j and k are calculated. That is, the LOS vector calculation unit 140 calculates the LOS vector for the three GPS satellites when the single difference of the three carrier phases is calculated, and when the double difference of the three carrier phases is calculated. Calculate LOS vectors for four GPS satellites.

  In the above LOS vector calculation method, the single positioning result obtained from the GPS receiver 952 has low accuracy and includes an error of several meters, but compared with the distance (about 20,000 km) between the GPS antenna 951 and the GPS satellite. Since the error is extremely small, the LOS vector obtained even if the single positioning result of the GPS receiver 952 is used has very high accuracy and represents an accurate direction.

The LOS vector may be obtained for one GPS antenna 951. When the LOS vector calculation unit 140 calculates the LOS vector for the GPS antenna 951 located at the point a, the LOS vector is calculated for the GPS antenna 951 located at the point b. You don't have to.
Further, the LOS vector calculation unit 140 may calculate the LOS vector using an arbitrary method. For example, the mobile body indicated by the angular velocity of the posture of the mobile body indicated by the measurement value of the gyro 953 and the measurement value of the odometer (not shown). Alternatively, the LOS vector may be calculated using the position of the GPS antenna 951 determined by dead reckoning based on the speed of.

<S240: Baseline length calculation process>
Baseline length calculation section 150 calculates the baseline length between GPS antennas 951 based on the carrier phase difference calculated by phase difference calculation section 130 in S210 and the LOS vector calculated by LOS vector calculation section 140 in S230.

FIG. 6 is a relationship diagram of the carrier phase difference, the LOS vector, and the baseline vector in the first embodiment.
A method for calculating the baseline length between the GPS antennas 951 by the baseline length calculation unit 150 will be described below with reference to FIG.

  In FIG. 6, the GPS antenna 951 is located at each of the points a and b, and both the GPS antenna 951 located at the point a and the GPS antenna 951 located at the point b are a carrier wave and a GPS satellite from the GPS satellite i. Assume that a carrier wave from j is received. Further, the following description will be made assuming that the GPS satellite is “satellite” and the GPS antenna 951 is “receiver”.

Here, the distance difference between the distance [rho _b ⁱ to receiver b from the distance [rho _a ⁱ and the satellite i to the receiver a satellite i showing single difference carrier phase of the receiver a receiver b is Since this corresponds to the inner product of the base line vector b _ab indicating the distance and direction from the receiver a to the receiver b and the LOS vector e _a ⁱ indicating the direction of the satellite i as viewed from the receiver a, The difference can be expressed by Equation 8 below.
Similarly, the double difference in the carrier phase can be expressed by Equation 9 below.

Here, in order to obtain the baseline vector b _ab in three-dimensional coordinates, the above equations 8 and 9 are generated for the single difference or double difference of the three carrier phases, and the following equations 10 and 11 are obtained.

From the equations 10 and 11, the base line vector b _ab can be expressed by the following equation 12.

The baseline length calculation unit 150 substitutes the single phase difference or double difference of the carrier phase calculated by the phase difference calculation unit 130 in S210 for “w”, and sets the LOS vector calculated by the LOS vector calculation unit 140 to “A” in S230. The base line vector is calculated by substituting and calculating the above equation 12, and the length of the calculated base line vector is calculated as the base line length.
At this time, if four or more carrier phase single or double differences are calculated in the phase difference calculation process (S210), the base line length calculation unit 150 calculates three single or double differences for each carrier phase. A baseline length is calculated for each combination.

  Returning to FIG. 5, the description of the multipath detection process (S120) will be continued.

<S250: Multipath determination processing A>
The multipath determination unit 160 calculates the baseline length between the GPS antennas 951 calculated in the baseline length calculation process (S240) (hereinafter referred to as the observation baseline length) (hereinafter referred to as the known baseline length between the GPS antennas 951). Multipath determination of the carrier wave used for calculation of the observation baseline length compared to the baseline length).
Here, the multipath determination unit 160 selects a multipath determination process to be executed based on the number of single differences or double differences of the carrier phase calculated in the phase difference calculation process (S210), and performs a single difference or two of the carrier phase. When the number of multiple differences is three, it is determined whether each carrier used for calculating the single difference or double difference of the three carrier phases includes a multipath wave, and the single difference or double of the carrier phase is determined. When the number of differences is four or more, a multipath wave is specified from each carrier used for calculating the single difference or the double difference of the four or more carrier phases.

  First, the multipath determination process A (S250) when three single differences or double differences of the carrier phase are calculated in the phase difference calculation process (S210) will be described.

When three single differences or double differences of the carrier phase are calculated in the phase difference calculation process (S210), the multipath determination unit 160 determines that the difference between the observation baseline length and the known baseline length is less than a predetermined threshold value. The carrier wave from each GPS satellite used to calculate the observation baseline length is determined not to include multipath, and if the difference between the observation baseline length and the known baseline length is equal to or greater than a predetermined threshold, the observation baseline length It is determined that a multipath is included in the carrier wave from each GPS satellite used for the calculation.
Then, as a determination result, for example, the multipath determination unit 160 determines whether or not the GPS observation information on the carrier wave used for calculation of the observation baseline length includes an observation error due to the multipath. Output to.

  Here, the known baseline length is determined by the platform 954 as shown in FIG. 1, which is installed on the moving body and the relative positional relationship between the GPS antennas 951 is fixed. GPS observation is performed in a plaza where multipath is unlikely to occur, and a relative position between GPS antennas 951 is obtained and calculated by DGPS (differential GPS) or static interference positioning, and stored in the orientation storage unit 190. However, the known baseline length may be obtained by an arbitrary method as long as the accuracy is higher than the estimation accuracy of the observed baseline length when calculated based on the multipath wave (for example, an error of several mm to several cm). For example, a design value of the base line length between the GPS antennas 951 in the platform 954 may be used.

  Further, the multipath determination unit 160 performs a hypothesis test using, for example, a standard deviation of 3σ (sigma) as a threshold used for comparison between the observation baseline length and the known baseline length. At this time, the multipath determination unit 160 determines whether or not the observation baseline length is included in the standard deviation (3σ) with the average value of the known baseline length, and if it is not included in the standard deviation (3σ) It is determined that a multipath is included in the carrier wave from each GPS satellite used for observation of the observation baseline length. The multipath determination unit 160 performs multipath determination using a predetermined threshold, thereby removing an error due to random noise of the GPS receiver 952 that falls within the predetermined threshold, and an observation error other than the random noise of the GPS receiver 952 That is, it is possible to determine the carrier wave in which the observation error due to multipath is included in the GPS observation information. Other observation errors such as GPS satellite clock error, GPS receiver clock error, ionospheric delay, and tropospheric delay are eliminated by calculating the single difference or double difference of the carrier as described above.

  Next, the multipath determination process A (S250) when four or more single phase differences or double differences of the carrier phase are calculated in the phase difference calculation process (S210) will be described.

When four or more carrier phase single or double differences are calculated in the phase difference calculation process (S210), three single or double carrier phase differences are combined in the baseline length calculation process (S240). A plurality of values are calculated for the observation baseline length between the two GPS antennas 951.
Therefore, the multipath determination unit 160 performs multipath determination by comparing each observation baseline length with a known baseline length.
Then, as a determination result, the multipath determination unit 160 uses, for example, the GPS observation information of the carrier wave used for calculation of each observation baseline length whose difference from the known baseline length is within a predetermined threshold as the position / orientation orientation determination unit 120. Notify

For example, when the single difference i, j, k, l of four carrier phases is calculated based on the respective carriers of the GPS satellites i, j, k, l in the phase difference calculation process (S210), the baseline length calculation process In (S240), the observation baseline length is calculated for a combination of the following single carrier phase single differences.
(1) Observation baseline length A: Combination of carrier phase single differences i, j, k (2) Observation baseline length B: Combination of carrier phase single differences i, j, l (3) Observation baseline length C: Carrier phase (4) Observation baseline length D: Combination of carrier phase single differences j, k, l At this time, the multipath determination unit 160 uses the observation baseline length A, observation baseline length B, observation Each of the baseline length C and the observation baseline length D is compared with a known baseline length.
As a result of the comparison determination, for example, when only the observation baseline length A is within a predetermined threshold range with respect to the known baseline length, the multipath determination unit 160 does not include a single carrier wave phase difference only in the observation baseline length A. The carrier wave from the GPS satellite l is identified as a multipath wave. Then, the multipath determination unit 160 observes the GPS observation information for each of the carrier wave from the GPS satellite i, the carrier wave from the GPS satellite j, and the carrier wave from the GPS satellite k used for calculating the observation baseline length A by multipath. The position / orientation orientation determination unit 120 is notified as GPS observation information that does not include an error.

Further, for example, in the phase difference calculation process (S210), GPS satellites i and j, GPS satellites i and k, GPS satellites i and l, and GPS satellite i based on the respective carriers of GPS satellites i, j, k, l, and m. When the double differences ij, ik, il, im of the four carrier phases for m and m are calculated, the baseline length for the following four combinations of the four carrier phase double differences is calculated in the baseline length calculation process (S240). Calculated.
(1) Observation baseline length A ′: Combination of carrier phase double differences ij, ik, il (2) Observation baseline length B ′: Combination of carrier phase double differences ij, ik, im (3) Observation baseline length C ′: Carrier phase double difference ij, il, im combination (4) Observation baseline length D ′: Carrier phase double difference ik, il, im combination At this time, the multipath determination unit 160 determines the observation baseline length. Each of A, observation baseline length B, observation baseline length C, and observation baseline length D is compared with a known baseline length.
As a result of the comparison determination, for example, when only the observation baseline length A is within a predetermined threshold range with respect to the known baseline length, the multipath determination unit 160 includes a double difference in the carrier phase only in the observation baseline length A. A carrier wave from a non-GPS satellite m is identified as a multipath wave. Then, the multipath determination unit 160 obtains GPS observation information for each of the carrier from the GPS satellite i, the carrier from the GPS satellite j, and the carrier from the GPS satellite k and the GPS satellite l used for the calculation of the observation baseline length A. The position / orientation orientation determination unit 120 is notified as GPS observation information that does not include observation errors due to multipath.

  As described above, the multipath determination unit 160 performs the multipath determination by comparing each observation baseline length calculated based on the single difference or double difference combination of each carrier phase with the known baseline length. A carrier wave that is not a wave can be identified. Further, when one multipath wave is included, the multipath determination unit 160 can specify the multipath wave as described above.

Next, the details of the position / orientation orientation processing (S130) in the first embodiment described with reference to FIG. 4 will be described.
In the position / orientation orientation determination process (S130), the position / orientation orientation determination unit 120 obtains GPS observation information of a carrier wave that is not a multipath wave based on the multipath determination result of the multipath detection unit 110 in the multipath detection process (S120). Use to locate the position and posture angle of the moving object.
The position / orientation orientation determination unit 120 may determine the position and orientation angle of the moving object by any method, and an example thereof is shown below.

FIG. 7 is a diagram illustrating an example of the configuration of the position / orientation orientation determination unit 120 according to the first embodiment.
FIG. 8 is a flowchart illustrating an example of the position / orientation orientation determination process (S130) according to the first embodiment.
An example of the position / orientation orientation determination process (S130) in the first embodiment will be described below with reference to FIGS.

  In FIG. 7, the position / orientation orientation determination unit 120 (positioning unit, orientation determination unit) includes a pseudo-range positioning unit 210, a baseline vector orientation determination unit 220, and a dead reckoning unit 230, and each unit will be described below with reference to FIG. Each process is executed using the CPU.

<S310: Positioning Method Determination Process>
First, the position / orientation orientation determination unit 120 selects a method for determining the position of the moving object according to the number of carriers (number of GPS satellites) determined not to be a multipath wave in the multipath detection process (S120).
Here, the number of carrier waves is the number of GPS satellites that have transmitted the carrier waves, and indicates the number of GPS satellites that can observe the carrier waves.

<S320: Pseudo distance positioning process>
When there are four or more GPS satellites in which the carrier wave can be observed as a direct wave instead of a multipath wave, the pseudorange positioning unit 210 performs GPS positioning based on the pseudorange to determine the position of the moving body.
For example, the pseudorange positioning unit 210 uses the four or more pseudoranges indicated by the GPS observation information of the carrier wave from the GPS satellite to calculate the three-dimensional coordinates of each GPS antenna 951 or any one of the GPS antennas 951 based on the principle of triangulation. Calculate the absolute position. At this time, if pseudoranges are observed for four carriers that have reached a specific GPS antenna 951 (for example, the main station in FIG. 1), the position of the GPS antenna 951 can be calculated. 210 may calculate the position of the GPS antenna 951 by the least square method using five or more pseudoranges. By positioning by the least square method using five or more pseudo distances, it is possible to obtain a positioning result with higher accuracy than the positioning results using four pseudo distances.
Then, the pseudo-range positioning unit 210 specifies the position of the moving body based on the calculated absolute position of the GPS antenna 951 and the installation position of the GPS antenna 951 in the moving body (relative position of the GPS antenna 951 with respect to the moving body).
Further, for example, the pseudo-range positioning unit 210 uses four or more carrier phases (corresponding to the distance between the GPS satellite and the GPS antenna 951) indicated by the GPS observation information of the carrier from the GPS satellite, as described above, Specify the position of the moving object.

<S330: Dead Reckoning Positioning Processing>
When the number of GPS satellites that can observe the carrier wave as a direct wave instead of a multipath wave is three or less, the dead reckoning unit 230 measures the measurement value of the gyro 953 and the odometer (not shown) from the previous positioning. The position of the moving body is measured by dead reckoning based on the angular velocity of the posture of the moving body indicated by the measurement value of the gyro 953 and the speed of the moving body indicated by the measurement value of the odometer.

<S340: Attitude Determination Method Determination Process>
Next, the position / orientation orientation determination unit 120 selects a method for determining the attitude angle of the moving object according to the number of carriers (number of GPS satellites) determined not to be multipath waves in the multipath detection process (S120). .

<S350: Baseline Vector Posture Orientation Processing>
Baseline vector attitude determination unit 220 operates when each GPS receiver 952 operates based on the same time information and there are three or more GPS satellites that can observe direct waves, and each GPS receiver 952 is different. When there are four or more GPS satellites that have been operated based on the time information and have been able to observe direct waves, the attitude angle of the moving body is determined based on the two baseline vectors.
The baseline vector attitude locating unit 220 uses GPS observation information about a carrier wave (direct wave) that is not a multipath wave, and performs the same as the baseline length calculation process (S240) by the baseline length calculation unit 150 of the multipath detection unit 110. Two baseline vectors are calculated. Then, the baseline vector posture locating unit 220 calculates a three-dimensional posture angle (rotation angle [roll angle], elevation angle [pitch angle], azimuth angle [yaw angle]) of the moving body based on the calculated two baseline vectors. . One baseline vector indicates an elevation angle and an azimuth angle, and the rotation angle is specified by the two baseline vectors.
For example, in FIG. 1, the baseline vector posture locating unit 220 calculates two baseline vectors, a baseline vector from the master station to the slave station (1) and a baseline vector from the master station to the slave station (2), and the posture of the moving object. Identify the corner.

<S360: Dead Reckoning Posture Orientation Processing>
The dead reckoning unit 230 operates when each GPS receiver 952 operates based on the same time information and the number of GPS satellites that can observe a direct wave is two or less, or when each GPS receiver 952 has a different time. When the number of GPS satellites that have been operated based on information and have been able to observe direct waves is 3 or less, the measured value of the gyro 953 from the time of the previous attitude angle determination indicates the measured value of the gyro 953 The posture angle of the moving body is determined by dead reckoning based on the angular velocity of the posture.

In the above, the following has been described.
The position / orientation locating system 100 is installed so that the relative positional relationship between the phase centers of each antenna is not shifted, and a plurality of GPS antennas in which the distance between the phase centers of any two antennas, that is, the baseline length is measured in advance, A GPS receiver and, if necessary, a sensor such as a gyro that measures the angular velocities of these multiple antennas are configured. The position / orientation positioning system 100 can calculate with a very high accuracy from the single or double difference between the receivers of the carrier phase, which can observe the distance between itself and the GPS satellite in millimeter order, and the GPS navigation message. Multipath detection is performed using a LOS vector from a self to a GPS satellite, and a highly accurate position and orientation orientation without multipath influence is determined.

  Considering clock errors of satellites and receivers, if at least 3 or 4 satellites can be observed in common with 2 antennas, use the single phase difference or double difference between the receivers of the carrier phase, Baseline vectors representing the three-dimensional positional relationship between the respective antenna phase centers can be obtained. However, if there is a multipath in the received positioning signal, the baseline vector is affected by this and cannot be obtained correctly. Therefore, the presence / absence of multipath can be detected by comparing the length of the obtained baseline vector with the baseline length measured in advance. The position / orientation locator 101 is a device that detects multipath based on such a principle.

  Further, according to the above principle, if any one of the satellite positioning signals for the three or four receivers has a multipath, it cannot be determined which one is the multipath. However, if satellite positioning signals for 4 or more aircraft can be received by 2 antennas, positioning can be received from which satellite by combining any 3 or 4 devices and performing multipath detection according to the above principle. It can be determined whether a multipath is included in the signal. The position / orientation locating device 101 is also a device that identifies a multipath based on such a principle.

  Further, the position / orientation locating device 101 is a device that performs positioning using GPS observation information (for example, a single phase difference or double difference between receivers of a carrier phase) from which multipath has been removed by the multipath detection mechanism described above. .

  Further, the position / orientation locating device 101 is a device for locating an attitude angle using GPS observation information (for example, a single difference or a double difference between receivers of a carrier wave phase) from which multipaths are removed by the multipath detection mechanism. But there is.

Embodiment 2. FIG.
In the position / orientation azimuth locating method in the first embodiment, multipath waves cannot be determined when three or more single or double differences in the carrier phase cannot be obtained.
Therefore, in the second embodiment, a method of detecting a multipath wave when three or more single phase differences or double differences of carrier phases cannot be obtained will be described.
Hereinafter, matters different from those of the first embodiment will be described, and items omitted from the description will be the same as those of the first embodiment.

FIG. 9 is a functional configuration diagram of the position and orientation determination apparatus 101 according to the second embodiment.
The position / orientation locating apparatus 101 according to the second embodiment includes a distance difference calculation unit 170 in addition to the functional configuration according to the first embodiment.

  The distance difference calculation unit 170 is a specific GPS antenna specified by an arbitrary method and a known baseline length indicating a distance between GPS antennas, a measured value of a gyro installed in a mobile body equipped with each GPS antenna, and an arbitrary method. The LOS vector indicating the direction from the GPS to a specific GPS satellite is input, and the distance difference between the GPS antennas between the GPS antennas is calculated based on the input known baseline length, the input gyro measurement value, and the input LOS vector. The estimated distance difference is calculated using the CPU.

  In addition, the multipath determination unit 160 compares the observation distance difference corresponding to the carrier wave phase difference between GPS antennas calculated by the phase difference calculation unit 130 and the estimated distance difference calculated by the distance difference calculation unit 170 using the CPU. When the observation distance difference is different from the estimated distance difference by a predetermined threshold or more, it is determined that each carrier wave used for calculation of the observation distance difference includes a multipath wave.

FIG. 10 is a flowchart showing the multipath detection process (S120) in the second embodiment.
The multipath detection process (S120) in the second embodiment determines whether three or more single phase differences or double differences in the carrier phase have been calculated in the phase difference calculation process (S210) with respect to the first embodiment. (S220: branching process A), when three or more single phase differences or double differences of the carrier phase cannot be calculated, the GPS satellites between the GPS antennas 951 based on the known baseline length, the measured value of the gyro 953, and the LOS vector Is calculated (S260: distance difference calculation process) and the calculated distance difference is compared with the single difference or double difference of the carrier phase to perform multipath determination (S270: multipath determination process B). It is characterized by.
The distance difference calculation process (S260) and the multipath determination process B (S270) will be described below.

<S260: Distance difference calculation process>
In the phase difference calculation process (S210), when three or more single phase differences or double differences cannot be calculated, the distance difference calculation unit 170 performs GPS based on the known baseline length, the measured value of the gyro 953, and the LOS vector. The distance difference between the antennas 951 and the GPS satellites is calculated.

When the single phase difference of the carrier wave phase is calculated in the phase difference calculation process (S210), the distance difference calculation unit 170 determines the posture angle of the moving body by dead reckoning based on the measured value of the gyro 953 from the previous posture angle determination time. The direction of the baseline vector between the GPS antennas 951 corresponding to the attitude angle of the moving body (hereinafter referred to as the baseline direction) is calculated. Then, the distance difference calculation unit 170 calculates the baseline vector indicated by the calculated baseline direction and the known baseline length, and the LOS vector to the GPS satellite from which the single phase difference of the carrier phase is calculated from the GPS antenna 951 as the base point of the baseline vector. To calculate the length of the LOS vector component of the known baseline length.
The length of the LOS vector component of this known baseline length corresponds to a single difference in the carrier phase for the GPS satellite between the GPS antennas 951. Hereinafter, the length corresponding to the single difference or double difference of the carrier phase calculated by the distance difference calculation unit 170 is set as the estimated distance difference.
For example, in FIG. 6, the length of the LOS vector _e ^{a i} component of the baseline vector _{b ab} is the distance between the carrier phase and the point b -GPS satellite i indicating the distance _[rho ^{a i} between a point -GPS satellite i [rho _b ^{This corresponds} to the difference (ρ _a ⁱ −ρ _b ⁱ ) from the carrier phase indicating ⁱ , that is, the single phase difference of the carrier phase for the GPS satellite i between the GPS antenna 951 at point a and the GPS antenna 951 at point b.
The method for calculating the known baseline length and the LOS vector is the same as in the first embodiment.

When the double phase difference of the carrier phase is calculated in the phase difference calculation process (S210), the distance difference calculation unit 170 calculates the LOS with the known baseline length for each of the two GPS satellites for which the double phase difference of the carrier phase has been calculated. The length of the vector component is calculated, and the difference (estimated distance difference) between the lengths of the two known baseline lengths of the LOS vector components is calculated.
The difference between the lengths of the LOS vector components of the two known baseline lengths corresponds to a double difference in carrier phase between the two GPS satellites between the GPS antennas 951.
For example, in FIG. 6, the distance difference calculation unit 170 corresponds to a double difference in carrier phase between the GPS satellite i and the GPS satellite j at the GPS antenna 951 at the point a and the GPS antenna 951 at the point b. For the baseline vector b _ab , the difference between the length of the LOS vector e _a ⁱ component and the length of the LOS vector e _a ^j component is calculated.

The distance difference calculation unit 170 calculates the estimated distance difference as described above for each of the single difference or double difference of each carrier phase calculated in the phase difference calculation process (S210).
For example, when the single phase difference of the carrier phase is calculated for the GPS satellite i, j, the distance difference calculation unit 170 calculates the estimated distance difference corresponding to the single phase difference of the carrier phase for the GPS satellite i and the carrier phase for the GPS satellite j. An estimated distance difference corresponding to a single difference is calculated.

  Next, the multipath determination process B (S270) in FIG. 10 will be described.

<S270: Multipath determination process B>
The multipath determination unit 160 uses the single difference or double difference (observation distance difference) of the carrier phase calculated in the phase difference calculation process (S210) as the single difference or two of the carrier phase calculated in the distance difference calculation process (S260). The multipath determination of the carrier used for calculating the single difference or double difference (observation distance difference) of the carrier phase is performed in comparison with the estimated distance difference corresponding to the multiple difference.
At this time, the multipath determination unit 160 performs the single phase difference or double difference of the carrier phase in the same manner as the processing for the observation baseline length and the known baseline length in the multipath determination processing A (S250) described in the first embodiment. If the difference between the (observation distance difference) and the estimated distance difference is less than a predetermined threshold, the carrier wave from the GPS satellite used to calculate the single or double difference (observation distance difference) of the carrier phase is not a multipath wave. If the difference between the single difference or double difference (observation distance difference) of the carrier phase and the estimated distance difference is equal to or greater than a predetermined threshold, the single difference or double difference (observation distance difference) of the carrier phase is calculated. It is determined that the carrier wave from the used GPS satellite is a multipath wave.

FIG. 11 is a diagram illustrating an example of the configuration of the position / orientation orientation determination unit 120 according to the second embodiment.
FIG. 12 is a flowchart illustrating an example of the position / orientation orientation processing (S130) according to the second embodiment.
An example of the position / orientation orientation determination process (S130) in the second embodiment will be described below with reference to FIGS.

  11, the position / orientation orientation determination unit 120 includes a dead reckoning unit 230, a Kalman filter unit 240, and a position / orientation correction unit 250, and each unit executes each process described below based on FIG. 12 using a CPU.

The Kalman filter unit 240 executes an extended Kalman filter process in the position / orientation orientation process (S130).
The extended Kalman filter process is a process for estimating an error of a state quantity based on both equations of a state equation that models the dynamics of the state quantity and an observation equation that formulates the relationship between the observed quantity and the state quantity. In particular, the extended Kalman filter performs error estimation based on a nonlinear state equation and observation equation, whereas the Kalman filter performs error estimation based on a linear state equation and observation equation. However, the Kalman filter unit 240 may perform normal Kalman filter processing.

<S410: Dead Reckoning Process>
The dead reckoning unit 230 uses the gyro 953 measurement value and the odometer measurement value from the previous position / orientation determination to determine the angular velocity of the moving body indicated by the gyro 953 measurement value and the measurement value of the odometer (not shown). The position and posture angle of the moving body are calculated by dead reckoning based on the speed of the moving body shown.

<S420: Kalman filter processing>
The Kalman filter unit 240 performs an extended Kalman filter process using an observation residual of a single difference or a double difference of the carrier phase as an observation amount, and the position and posture angle of the moving object calculated in the dead reckoning process (S410) and the dead reckoning process ( An error is estimated for the state quantity such as the output rate (measured value) of the gyro 953 used in S410.
At this time, the position / orientation orientation determination unit 120 calculates the difference between the single difference or double difference of the carrier phase and the estimated distance difference calculated in the multipath determination process B (S270) as the single difference or double difference of the carrier phase. It is an observation residual.

<S430: Position / Orientation Correction Process>
The position / orientation correction unit 250 corrects (adds) the position and posture angle of the moving object calculated in the dead reckoning process (S410) using the error estimated by the Kalman filter process (S420) as a correction amount. And orientation angle.
The dead reckoning unit 230 performs dead reckoning using the output rate (measured value) of the gyro 953 corrected with the error estimated by the Kalman filter process (S420) in the next and subsequent dead reckoning processes (S410).

  Similarly to the first embodiment, the position / orientation / orientation determination unit 120 determines the position and orientation angle of the moving object based on the pseudo distance and the baseline vector, if possible, and based on the pseudo distance and the baseline vector. As described above, the position or posture angle of the moving body that cannot be determined may be determined by dead reckoning and Kalman filter processing.

In the above, the following has been described.
The multipath detection process (S120) in the first embodiment cannot be applied when the number of satellites that can be commonly observed by two or three antennas is two or three or less. However, if the angular velocity of the antenna by the gyro sensor is used, the baseline vector calculated when three or four or more satellites are observed in common with two or three antennas is integrated to obtain the current baseline vector. Can be predicted. By combining this with the single phase difference or double difference between the receivers of the carrier phase, multipath detection is performed even if the number of commonly observed satellites is one (two in the case of a double difference). I can do it. The position / orientation locator 101 is a device that detects multipath based on such a principle.

Embodiment 3 FIG.
FIG. 13 is a flowchart showing multipath detection processing (S120) in the third embodiment.
As shown in FIG. 13, even if the number of single-phase or double-differences in the carrier phase calculated in the phase difference calculation process (S210, refer to Embodiment 1 above) is different, the distance difference calculation process (S260, The multipath may be detected by performing the above-described second embodiment) and the multipath determination process B (S270, see the second embodiment).
Other matters in the third embodiment are the same as those in the first embodiment or the second embodiment.

1 is a schematic diagram of a configuration of a position / orientation orientation system 100 according to Embodiment 1. FIG. 1 is a hardware configuration diagram of a position and orientation determination system 100 according to Embodiment 1. FIG. FIG. 3 is a functional configuration diagram of a position / orientation locating apparatus 101 according to the first embodiment. 3 is a flowchart showing a position / orientation locating method according to the first embodiment. 5 is a flowchart showing multipath detection processing (S120) in the first embodiment. FIG. 4 is a relationship diagram of a carrier phase difference, a LOS vector, and a baseline vector in the first embodiment. FIG. 3 is a diagram illustrating an example of a configuration of a position / orientation orientation determination unit 120 according to the first embodiment. 5 is a flowchart illustrating an example of a position / orientation orientation process (S130) according to the first embodiment. FIG. 4 is a functional configuration diagram of a position / orientation locating apparatus 101 according to a second embodiment. 9 is a flowchart showing multipath detection processing (S120) in the second embodiment. FIG. 10 is a diagram illustrating an example of a configuration of a position / orientation orientation determination unit 120 according to Embodiment 2. 9 is a flowchart illustrating an example of a position / orientation orientation process (S130) according to the second embodiment. 10 is a flowchart showing multipath detection processing (S120) in the third embodiment.

Explanation of symbols

  100 position and orientation determination system, 101 position and orientation determination device, 110 multipath detection unit, 120 position and orientation direction determination unit, 130 phase difference calculation unit, 140 LOS vector calculation unit, 150 baseline length calculation unit, 160 multipath determination unit, 170 Distance difference calculation unit, 190 orientation storage unit, 210 pseudorange positioning unit, 220 baseline vector attitude determination unit, 230 dead reckoning unit, 240 Kalman filter unit, 250 position and orientation correction unit, 911 CPU, 920 storage device, 921 OS, 923 program Group, 924 file group, 951 GPS antenna, 952 GPS receiver, 953 gyro, 954 platform.

Claims (11)

A multipath wave is included in each carrier wave transmitted from each GPS satellite and received by each GPS antenna in a moving body in which a plurality of GPS (Global Positioning System) antennas are installed with the relative positions between the GPS antennas fixed. Multipath detection device that detects whether or not
Information on the carrier phase indicating the distance between each GPS satellite and each GPS antenna in terms of the number of carriers is input, and based on the input carrier phase information, the difference in the carrier phase between the GPS antennas and the same GPS satellite is determined by the CPU (Central A phase difference calculation unit that calculates using Processing Unit),
Input a carrier phase difference between GPS antennas calculated by the phase difference calculation unit and a LOS (Line Of Light) vector indicating a direction from a specific GPS antenna specified by an arbitrary method to a specific GPS satellite, A baseline length calculation unit that calculates a baseline length indicating a distance between GPS antennas as an observation baseline length based on the input carrier phase difference and the input LOS vector using a CPU;
When the known baseline length indicating the distance between GPS antennas calculated in advance and the observed baseline length calculated by the baseline length calculation unit are compared using a CPU, and the observed baseline length differs from the known baseline length by a predetermined threshold or more A multipath detection apparatus comprising: a multipath determination unit that determines that a multipath wave is included in each carrier wave used for calculating the observation baseline length. The multipath detection device further includes:
The navigation message indicating the position of each GPS satellite propagated by the carrier wave and the positioning information indicating the position of the GPS antenna positioned based on the carrier wave are input, and the position of each GPS satellite indicated by the input navigation message is input. A LOS vector calculation unit that calculates a LOS vector indicating a direction from the GPS antenna to the GPS satellite based on the position of each GPS antenna indicated by the positioning information using a CPU;
The multipath detection device according to claim 1, wherein the baseline length calculation unit calculates the observation baseline length based on the LOS vector calculated by the LOS vector calculation unit. The phase difference calculation unit calculates four or more carrier phase differences,
The baseline length calculation unit calculates the observation baseline length for each combination of carrier phase differences by combining three carrier phase differences calculated by the phase difference calculation unit,
The multipath determination unit determines each observation baseline length calculated by the baseline length calculation unit, and identifies a multipath wave based on a determination result for each observation baseline length. The multipath detection device according to claim 2. The phase difference calculation unit inputs carrier phase information observed based on the same time information for three or more GPS satellites, and a single carrier phase indicating a difference in carrier phase with the same GPS satellite between GPS antennas. The multipath detection device according to claim 1, wherein the difference is calculated for each GPS satellite. The phase difference calculator inputs carrier phase information for four or more GPS satellites, and calculates the difference between the carrier phase of the first GPS satellite between the GPS antennas and the second GPS satellite between the GPS antennas. The multipath detection device according to any one of claims 1 to 3, wherein a double difference in carrier phase indicating a difference from a difference in carrier phase is calculated for each GPS satellite. A multipath wave is included in each carrier wave transmitted from each GPS satellite and received by each GPS antenna in a moving body in which a plurality of GPS (Global Positioning System) antennas are installed with the relative positions between the GPS antennas fixed. Multipath detection device that detects whether or not
Information on the carrier phase indicating the distance between each GPS satellite and each GPS antenna in terms of the number of carriers is input, and based on the input carrier phase information, the difference in the carrier phase between the GPS antennas and the same GPS satellite is determined by the CPU (Central A phase difference calculation unit that calculates using Processing Unit),
From a specific GPS antenna specified by any method and a measured value of a gyroscope installed on the moving body having each GPS antenna and a known baseline length indicating a distance between GPS antennas calculated in advance to a specific GPS satellite A LOS (Line Of Light) vector indicating the direction of the GPS is input, and the distance difference between the GPS antennas between the GPS antennas is estimated based on the input known baseline length, the input gyro measurement value, and the input LOS vector. A distance difference calculation unit that calculates using a CPU as a distance difference;
The observed distance difference corresponding to the carrier phase difference between the GPS antennas calculated by the phase difference calculator is compared with the estimated distance difference calculated by the distance difference calculator using the CPU, and the observed distance difference is the estimated distance difference. A multipath detection unit comprising: a multipath determination unit that determines that each carrier wave used for calculating the observation distance difference includes a multipath wave when the difference is more than a predetermined threshold. apparatus. The multipath detection device according to any one of claims 1 to 6,
A positioning unit that measures the position of the moving body using a CPU based on observation information of a carrier wave determined by the multipath determination unit of the multipath detection device as not a multipath wave. apparatus. The multipath detection device according to any one of claims 1 to 6,
And a posture locating unit that calculates a posture angle of the moving body using a CPU based on observation information of a carrier wave determined by the multipath determination unit of the multipath detection device as not a multipath wave. Posture orientation locating device. A multipath wave is included in each carrier wave transmitted from each GPS satellite and received by each GPS antenna in a moving body in which a plurality of GPS (Global Positioning System) antennas are installed with the relative positions between the GPS antennas fixed. A multipath detection method of a multipath detection device for detecting whether or not
The phase difference calculation unit inputs carrier phase information indicating the distance between each GPS satellite and each GPS antenna by the number of carriers, and based on the inputted carrier phase information, the carrier phase of the same GPS satellite between the GPS antennas is input. A phase difference calculation process for calculating the difference using a CPU (Central Processing Unit) is performed.
The LOS (Line Of Light) vector indicating the difference in the carrier wave phase between the GPS antennas calculated by the phase difference calculation unit and the direction from the specific GPS antenna specified by an arbitrary method to the specific GPS satellite by the baseline length calculation unit And, based on the input carrier phase difference and the input LOS vector, the base line length indicating the distance between the GPS antennas is calculated as the observation base line length using the CPU,
The multipath determination unit compares the known baseline length indicating the distance between the GPS antennas calculated in advance with the observation baseline length calculated by the baseline length calculation unit using the CPU, and the observation baseline length is determined from the known baseline length. Multipath detection of a multipath detection device, which performs multipath determination processing for determining that each carrier wave used for calculation of the observation baseline length includes a multipath wave when different from a threshold value Method. A multipath wave is included in each carrier wave transmitted from each GPS satellite and received by each GPS antenna in a moving body in which a plurality of GPS (Global Positioning System) antennas are installed with the relative positions between the GPS antennas fixed. A multipath detection method of a multipath detection device for detecting whether or not
The phase difference calculation unit inputs carrier phase information indicating the distance between each GPS satellite and each GPS antenna by the number of carriers, and based on the inputted carrier phase information, the carrier phase of the same GPS satellite between the GPS antennas is input. A phase difference calculation process for calculating the difference using a CPU (Central Processing Unit) is performed.
A distance difference calculation unit calculates a known baseline length indicating a distance between GPS antennas, a measured value of a gyro installed in the moving body including each GPS antenna, and a specific GPS antenna specified by an arbitrary method. A LOS (Line Of Light) vector indicating the direction to a specific GPS satellite is input, and the same GPS satellite between the GPS antennas based on the input known baseline length, the input gyro measurement, and the input LOS vector A distance difference calculation process is performed in which the distance difference is calculated using the CPU as an estimated distance difference,
The multipath determination unit compares the observation distance difference corresponding to the carrier phase difference between the GPS antennas calculated by the phase difference calculation unit with the estimated distance difference calculated by the distance difference calculation unit using the CPU, and the observation distance Multipath determination processing is performed to determine that a multipath wave is included in each carrier used for calculation of the observation distance difference when the difference is different from the estimated distance difference by a predetermined threshold or more. Multipath detection method of multipath detection apparatus.   A multipath detection program for causing a computer to execute the multipath detection method according to claim 9.

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