JP2010164339A - Gnss reception system and geolocation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the effect of a multipath and to improve the measurement accuracy. <P>SOLUTION: This GNSS reception system, performing a geolocation operation based on a geolocation signal transmitted from a GNSS satellite, includes a plurality of antennas which are so disposed that phase differences arise among direct wave and reflected waves, in a state where the GNSS reception system picks up the geolocation signal from the same GNSS satellite; a pseudo-range calculating part which determines a pseudo-range between the GNSS satellite and the GNSS reception system, using a code contained in the geolocation signal from the same GNSS satellite; a pseudo-range difference calculating part which determines a difference of each pseudo-range; a determining part which determines that the geolocation signal from the GNSS satellite is affected by the multipath, based on the difference; a location estimating part which estimates the location of the GNSS reception system, based on information other than the geolocation signal from the GNSS satellite; and a location information output part which outputs location information estimated by the location estimating part, when the geolocation signal is affected by the multipath. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a GNSS receiver and a positioning method for receiving and positioning a signal from a GNSS orbiting satellite.

  The Global Navigation Satellite System (GNSS) is a system that obtains the distance from each GNSS satellite by capturing three navigation satellites (GNSS orbiting satellites) (hereinafter referred to as GNSS satellites) from the aircraft, It is a navigation system that can obtain the flight position in three dimensions of the aircraft by adjusting the time with the signal from the eye navigation satellite. Satellite navigation includes the Global Positioning System (GPS), Galileo, and others.

  For example, a GNSS receiver is mounted on a moving body and measures the position and speed of the moving body. For example, the GNSS receiver receives the radio waves from a plurality of GNSS satellites to measure the distances (pseudo distances) from the plurality of GNSS satellites to the GNSS receiver, and based on the pseudo distances, the GNSS reception Measures the moving object equipped with the device. The signal emitted by the GNSS satellite arrives at the GNSS receiver with a delay in the distance between the GNSS satellite and the GNSS receiver by the time the radio wave propagates. Therefore, if the time required for radio wave propagation is obtained for a plurality of GNSS satellites, the position of the GNSS receiver can be obtained by positioning calculation. For example, for radio waves emitted by a plurality of GNSS satellites, the distance from each GNSS satellite to the GNSS receiver is determined by the distance measuring unit of the GNSS receiver. Then, the positioning calculation unit obtains the position of the GNSS receiver based on the distance obtained by the ranging unit.

JP 2000-346655 A JP 2003-279635 A

  In the GNSS receiver, there may be a case where a reflected wave that is reflected by a building or the like is received in addition to a direct wave that arrives through a route directly connecting the GNSS receiver and the GNSS satellite. As described above, a phenomenon in which radio waves from a GNSS satellite are received by a GNSS receiver through two or more paths is called multipath. When the GNSS receiver obtains the pseudo distance based on the reflected wave instead of the direct wave, the arrival time of the reflected wave is longer than that of the direct wave, so that the error is larger than the pseudo distance obtained by the direct wave.

  For example, in a GPS receiver, a correlation between a received signal from a GPS satellite and a replica signal of the received signal is obtained, and a pseudo distance is obtained from the position of the correlation peak. In a multipath environment, when a pseudorange is obtained based on received signals from a plurality of GPS satellites, the received signal includes a reflected wave. Therefore, the position of the correlation peak between the received signal and a replica signal of the received signal The variation of the is increased. Since the variation in the position of the correlation peak between the received signal and the replica signal of the received signal becomes large, the variation in the pseudo distance also increases, and the error in the positioning result also increases.

  On the other hand, as a method for estimating the position of a moving body, there is navigation called INS (Inertial Navigation System) navigation. In INS navigation, the position of a moving body is estimated by integrating the movement of the moving body based on an acceleration detector mounted on the moving body itself called an IMU (Inertial Measurement Unit).

  As a countermeasure against multipath, information indicating whether radio waves sent from GPS satellites are affected by the multipath is stored for each section, and whether there is an influence of the multipath around the measured position. Discloses a method of correcting the positioning result (see, for example, Patent Document 1).

  In addition, the multipath size is calculated from the positioning position using the satellite signal and the estimated position using the moving speed and azimuth angle of the moving body, and moves according to the multipath signal corresponding to the multipath size. A technique for obtaining the position of the body is disclosed (for example, see Patent Document 2).

  The present invention has been made in view of the above points, and an object of the present invention is to provide a GNSS receiver and a positioning method that can reduce the influence of multipath and improve positioning accuracy.

In order to solve the above problems, the GNSS receiver
A GNSS receiver that performs a positioning operation based on a positioning signal transmitted from a GNSS satellite,
In a state where the GNSS receiver captures a positioning signal from the same GNSS satellite, a plurality of antennas arranged so as to cause a phase difference between the direct wave and the reflected wave,
Using a code included in a positioning signal from the same GNSS satellite received by each antenna, a pseudorange calculation unit for obtaining a pseudorange between the GNSS satellite and the GNSS receiver,
A pseudo-range difference calculation unit for obtaining a difference between the pseudo-ranges obtained by the pseudo-range calculation unit;
A determination unit that determines that a positioning signal from the GNSS satellite is affected by a multipath based on the difference obtained by the pseudorange difference calculation unit;
A position estimation unit that estimates the position of the GNSS receiver based on information other than the positioning signal from the GNSS satellite;
A position information output unit that outputs the position information estimated by the position estimation unit when the determination unit determines that it is affected by multipath.

In other examples,
The plurality of antennas are arranged in the direction perpendicular to the traveling direction of the GNSS receiver by being separated by an interval of 1/4 to 1/2 of the wavelength of the positioning signal.

In other examples,
The determination unit determines that there is no influence of multipath when the difference obtained by the pseudo-range difference calculation unit is zero.

This GNSS receiver
A GNSS receiver that performs a positioning operation based on a positioning signal transmitted from a GNSS satellite,
Multiple antennas,
Using a code included in a positioning signal from the same GNSS satellite received by each antenna, a pseudorange calculation unit for obtaining a pseudorange between the GNSS satellite and the GNSS receiver,
A pseudo-range difference calculation unit for obtaining a difference between the pseudo-ranges obtained by the pseudo-range calculation unit;
Calculate the position of the GNSS satellite based on the positioning signal corresponding to each pseudo distance obtained by the pseudo distance calculation unit, and based on the distance between the position of the GNSS satellite and the plurality of antennas, the pseudo distance A pseudo-range difference estimator for estimating the difference between
Based on the pseudorange difference obtained by the pseudorange difference calculation unit and the pseudorange difference estimated by the pseudorange difference estimation unit, the positioning signal from the GNSS satellite is affected by multipath. A determination unit for determining that;
A position estimation unit that estimates the position of the GNSS receiver based on information other than the positioning signal from the GNSS satellite;
A position information output unit that outputs the position information estimated by the position estimation unit when the determination unit determines that it is affected by multipath.

In other examples,
When the difference between the pseudo-range difference obtained by the pseudo-range difference calculation unit and the pseudo-range difference estimated by the pseudo-range difference estimation unit is zero, the determination unit determines the influence of multipath. It is determined that it has not been received.

This positioning method is
A positioning method in a GNSS receiver that performs a positioning operation based on a positioning signal transmitted from a GNSS satellite,
In a state where the GNSS receiver captures a positioning signal from the same GNSS satellite, it is from the same GNSS satellite received by a plurality of antennas arranged so that a phase difference occurs between the direct wave and the reflected wave. Using a code included in the positioning signal, a pseudo-range calculation step for obtaining a pseudo-range between the GNSS satellite and the GNSS receiver,
A pseudo distance difference calculating step for obtaining a difference between the pseudo distances obtained by the pseudo distance calculating step;
A determination step of determining that the positioning signal from the GNSS satellite is affected by a multipath based on the difference obtained by the pseudo-range difference calculation step;
Based on information other than positioning signals from GNSS satellites, a position estimation step for estimating the position of the GNSS receiver,
A position information output step of outputting the position information estimated by the position estimation step when it is determined by the determination step that there is a multipath effect.

This positioning method is
A positioning method in a GNSS receiver that performs a positioning operation based on a positioning signal transmitted from a GNSS satellite,
A pseudo-range calculation step for obtaining a pseudo-range between the GNSS satellite and the GNSS receiver using a code included in a positioning signal from the same GNSS satellite received by a plurality of antennas of the GNSS receiver; ,
A pseudo distance difference calculating step for obtaining a difference between the pseudo distances obtained by the pseudo distance calculating step;
Calculate the position of the GNSS satellite based on the positioning signal corresponding to each pseudo distance obtained by the pseudo distance calculation step, and based on the distance between the position of the GNSS satellite and the plurality of antennas, the pseudo distance A pseudo-range difference estimation step for estimating a difference between
The positioning signal from the GNSS satellite is affected by the multipath based on the pseudorange difference obtained by the pseudorange difference calculation step and the pseudorange difference estimated by the pseudorange difference estimation step. A determination step for determining that,
Based on information other than positioning signals from GNSS satellites, a position estimation step for estimating the position of the GNSS receiver,
A position information output step of outputting the position information estimated by the position estimation step when it is determined by the determination step that there is a multipath effect.

  According to the disclosed GNSS receiver and positioning method, the influence of multipath can be reduced and the measurement accuracy can be improved.

It is a functional block diagram of a GNSS receiver according to an embodiment. It is explanatory drawing which shows arrangement | positioning of the antenna in the GNSS receiver according to one Example. It is explanatory drawing which shows the correlation process in the GNSS receiver according to one Example. It is explanatory drawing which shows the correlation process in the GNSS receiver according to one Example. It is a functional block diagram of a GNSS receiver according to an embodiment. It is a flowchart which shows operation | movement of the GNSS receiver according to one Example. It is explanatory drawing which shows arrangement | positioning of the antenna in the GNSS receiver according to one Example. It is a functional block diagram of a GNSS receiver according to an embodiment. It is explanatory drawing which shows control of the antenna in the GNSS receiver according to one Example. It is a functional block diagram of a GNSS receiver according to an embodiment. It is a flowchart which shows operation | movement of the GNSS receiver according to one Example. It is a functional block diagram of a GNSS receiver according to an embodiment. It is explanatory drawing which shows the correlation process in the GNSS receiver according to one Example. It is explanatory drawing which shows the correlation process in the GNSS receiver according to one Example. It is a flowchart which shows operation | movement of the GNSS receiver according to one Example. It is a functional block diagram of a GNSS receiver according to an embodiment. It is explanatory drawing which shows the correlation process in the GNSS receiver according to one Example. It is explanatory drawing which shows the correlation process in the GNSS receiver according to one Example. It is a flowchart which shows operation | movement of the GNSS receiver according to one Example. It is a functional block diagram of a GNSS receiver according to an embodiment. It is a functional block diagram of a GNSS receiver according to an embodiment.

  Next, the best mode for carrying out the present invention will be described based on the following embodiments with reference to the drawings.

  In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

(system)
A GNSS (Global Navigation Satellite System) according to the present embodiment includes a GNSS satellite that orbits the earth and a GNSS receiver 100 that is located on the earth and can move on the earth. In this embodiment, GPS will be described as an example of GNSS. You may apply to GNSS other than GPS.

  GNSS satellites always broadcast navigation messages (satellite signals) to the earth. The navigation message includes satellite orbit information (ephemeris and almanac) for the corresponding GNSS satellite, clock correction values, and ionospheric correction coefficients. The navigation message is spread by the C / A code, is carried on the L1 band carrier (frequency: 1575.42 MHz), and is constantly broadcast toward the earth. Note that the L1 band carrier 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, and are code strings in which -1 and 1 are arranged irregularly and periodically.

  Currently, about 30 GNSS satellites orbit the earth at an altitude of about 20,000 km, and there are 6 earth-orbiting planes tilted by 55 degrees, each with 4 or more GNSS satellites. Are evenly arranged. Therefore, at least 5 or more GNSS satellites can be observed at any time anywhere on the earth as long as the sky is open.

(First embodiment)
(GNSS receiver)
The GNSS receiver 100 is mounted on a mobile object, for example. The mobile body includes a vehicle, a motorcycle, a train, a ship, an aircraft, a robot, and the like, and an information terminal such as a portable terminal that moves as a person moves.

  The cause of the variation in the correlation value between the C / A code and the C / A code replica signal obtained by radio waves from the GNSS satellite in a multipath environment is that the phase of the reflected wave changes within the wavelength of the carrier wave. It is. When the GNSS receiver has only one antenna and receives a radio wave (synthetic wave) from a GNSS satellite with the one antenna, the correlation processing is performed in a state where the phase of the reflected wave included in the radio wave is unknown. Since the correlation process is performed in a state where the phase of the reflected wave is unknown, the correlation value varies.

  The GNSS receiver 100 according to the present embodiment determines that the GNSS receiver 100 is affected by multipaths when there are a plurality of antennas and the pseudoranges obtained by the received radio waves from the antennas are different. Each antenna is arranged so that a phase difference occurs between the direct wave and the reflected wave in a state where the same satellite is captured and tracked. In this embodiment, a case where two antennas are provided will be described as an example, but three or more antennas may be provided. Further, when it is determined that the GNSS receiving apparatus is affected by multipath, the GNSS receiving apparatus outputs a position estimation result estimated by the INS as position information. In other words, the position information is taken over from the positioning calculation result by the GNSS positioning calculation to the position estimation result estimated by the INS. Position estimation estimated by INS before the positioning accuracy of the positioning calculation result by GNSS positioning calculation decreases by outputting the position estimation result estimated by INS when it is determined that it is affected by multipath The result can be switched, and the influence of multipath on the position information can be reduced.

  FIG. 1 shows the GNSS receiver 100.

The GNSS receiver 100 includes an antenna 102 (102 ₁ , 102 ₂ ), a high frequency processing unit 104 (104 ₁ , 104 ₂ ) provided corresponding to each antenna 102, a signal processing unit 106, and a positioning calculation unit 116. An INS position estimation unit 118, a position calculation processing unit 120, a map matching processing unit 122, and a map DB (database) 124. The signal processing unit 106 includes a correlator 108 (108 ₁ , 108 ₂ ) and a pseudo distance calculation unit 110 (110 ₁ , 110 ₂ ) provided corresponding to each antenna 102, a pseudo distance difference calculation unit 112, and a determination And a processing unit 114.

Since the high frequency processing units 104 ₁ and 104 ₂ have the same function, they will be described as the high frequency processing unit 104. Since the correlators 108 ₁ and 108 ₂ have the same function, they will be described as the correlator 108. Since the pseudo distance calculation units 110 ₁ and 110 ₂ have the same function, they will be described as the pseudo distance calculation unit 110.

The antennas 102 ₁ and 102 ₂ are arranged so that a phase difference occurs between the direct wave and the reflected wave in a state where the same satellite is captured and tracked. Antennas 102 ₁ and 102 ₂ receive radio waves from GNSS satellites. However, when determining the presence or absence of multipath effects, the signal processing unit 106 uses radio waves received from the same GNSS satellite.

From the viewpoint of increasing the phase difference between the direct wave and the reflected wave, for example, as shown in FIG. 2, the antennas 102 ₁ and 102 ₂ are arranged in a direction perpendicular to the traveling direction of the GNSS receiver 100. In addition, it is preferable that the two antennas be spaced apart by an antenna interval R. Specifically, the antennas 102 ₁ and 102 ₂ are arranged so that the directivities thereof are perpendicular to the traveling direction of the GNSS receiver 100. For example, the antenna interval R is preferably about 1/4 to 1/2 of the wavelength of a radio wave (carrier wave) for positioning from the GNSS satellite. It is assumed that the positioning signal is reflected by the wall (reflector) 50 positioned in parallel with the traveling direction of the GNSS receiving apparatus 100, and the reflected positioning signal is received by the GNSS receiving apparatus 100 as a reflected wave. . By placing the two antennas at an interval of about 1/4 to 1/2 the wavelength of the positioning radio wave (carrier wave) from the GNSS satellite, the phase difference of the signals received between the antennas is maximized it can. As a result, multipath can be detected with a small number of antennas.

In the GNSS receiver 100 shown in FIG. 2, the traveling direction of the mobile body on which the GNSS receiver 100 is mounted is the direction from the front to the back of the specification (paper surface), and is on the right side with respect to the traveling direction of the mobile body A case where the wall (reflector) 50 exists will be described. Radio waves from the GNSS satellite are reflected by the wall 50 and received. Since the antennas 102 ₁ and 102 ₂ are arranged perpendicular to the traveling direction of the GNSS receiver 100 and separated by the antenna interval R, the phase difference between the two antennas can be increased.

  The high frequency processing unit 104 is connected to the antenna 102 and amplifies a weak RF signal supplied via the antenna 102 to a level at which A / D conversion can be performed, and at the same time, an intermediate frequency (typically 1 MHz to 20 MHz). Then, the high frequency processing unit 104 converts the signal converted to the intermediate frequency into a digital intermediate frequency signal so that digital signal processing can be performed. The output signal of the high frequency processing unit 104 is input to the correlator 108.

The correlator 108 is connected to the high frequency processing unit 104. The correlator 108 generates a C / A code replica signal. The correlator 108 performs C / A code synchronization by shifting the phase of the C / A code replica signal with respect to the L1 band C / A code. Actually, the digital intermediate frequency signal is multiplied by a replica carrier supplied from a PLL (not shown) by a mixer (not shown) and then input to the correlator 108. The correlators 108 ₁ and 108 ₂ track the radio waves from the same captured GNSS satellite by tracking the code phase at which the correlation value of the C / A code replica signal with respect to the C / A code peaks. Correlators 108 ₁ and 108 ₂ input the correlation results to pseudo-range calculators 110 ₁ and 110 ₂ , respectively.

The pseudorange calculator 110 is connected to the correlator 108 and calculates a pseudorange based on the correlation result by the correlator 108. Here, the pseudo-distances calculated by the pseudo range calculation unit 110 ₁ is referred to as pseudoranges A, the pseudo-distances calculated by the pseudo range calculation unit 110 ₂ is called a pseudo-range B. The pseudo distance calculation units 110 ₁ and 110 ₂ may output the code phases at which the correlation value of the C / A code replica signal with respect to the C / A code peaks as the pseudo distance A and the pseudo distance B, respectively. .

Capturing the same GNSS satellites in tracking state, because it is the antenna 102 is arranged so that the phase difference is produced between the direct wave and the reflected wave, based on the radio wave (composite wave) received by the antenna 102 ₁ pseudorange computed based on the radio waves received by the pseudo-range and the antenna 102 ₂ calculated Te and has a different value in the multipath environment.

3 and 4 show an example of the correlation characteristics of the C / A code replica signal for C / A code obtained by the pseudo distance calculation unit 110 ₁ and 110 _2. As shown in the correlation characteristic, the peak of the correlation value depends on the correlation value of the replica signal of the C / A code with respect to the L1 band C / A code of the direct wave and the reflected wave. 3 and 4, the horizontal axis represents time, and the vertical axis represents the correlation value. 3 and 4, the prompt PA and prompt PB shows a peak of the correlation values obtained by the respective pseudo-range calculation section 110 ₁ and 110 _2. By calculating the pseudoranges from the times tsa and tsb at which the prompt PA and the prompt PB are obtained, pseudoranges A and B are obtained, respectively. The C / A code replica signal is a code having the same arrangement of +1 and −1 with respect to the C / A code put on the satellite signal from the GPS satellite. The C / A code synchronization is to synchronize the phase of the C / A code replica signal with the phase of the received C / A code. The C / A code has a 1-bit length of 1 μs, and a length corresponding to 1 bit is about 300 m. Therefore, the pseudorange ρ related to the GPS satellite is calculated as ρ = N × 300 when the Nth bit of the C / A code is received on the assumption that the C / A code is the 0th bit in the GPS satellite. Can do. That is, the pseudo distance ρ is calculated by measuring the difference between the code phase time on the GPS satellite side of the received C / A code and the time on the GPS receiver side. The pseudo distance calculation unit 110 inputs the pseudo distance to the pseudo distance difference calculation unit 112.

The pseudo distance difference calculation unit 112 is connected to the pseudo distance calculation units 110 ₁ and 110 ₂ . Pseudorange difference calculation unit 112, a pseudo distance A input by the pseudorange calculation unit 110 _1, based on the pseudo-range B input by the pseudorange calculation unit 110 _2, the pseudo distance A and the pseudo distance B Calculate the difference. In order to prevent the difference from becoming negative, the absolute value of the difference between the pseudo distance A and the pseudo distance B (hereinafter referred to as “pseudo distance difference”) may be obtained. That is, the pseudo distance difference calculation unit 112 determines whether the pseudo distance A and the pseudo distance B are the same value, in other words, whether the difference is within the error range. The pseudo distance A and the pseudo distance B are calculated based on radio waves from the same GNSS satellite. Further, the antennas 102 ₁ and 102 ₂ are arranged so that a phase difference occurs between the direct wave and the reflected wave in a state where the same satellite is captured and tracked. Therefore, when the GNSS receiver 100 is located in a multipath environment and is affected by multipath, the pseudo distance A and the pseudo distance B are different from each other, so that the difference is different from zero. . On the other hand, when the GNSS receiving apparatus 100 is not located in the multipath environment, the pseudo distance A and the pseudo distance B are almost the same value because the multipath is not affected, and the difference between them is zero. The pseudo distance difference calculation unit 112 inputs the pseudo distances A and B to the positioning calculation unit 116 and inputs the pseudo distance difference between the pseudo distance A and the pseudo distance B to the determination processing unit 114.

  The determination processing unit 114 is connected to the pseudo-range difference calculation unit 112, and based on the pseudo-range difference input by the pseudo-range difference calculation unit 112, the radio waves from the GNSS satellite corresponding to the pseudo-range difference are Determine if it is affected by a path. The determination processing unit 114 determines that it is affected by multipath when the difference in pseudo distance is a value larger than zero. Further, the determination processing unit 114 may determine that it is affected by multipath when the pseudo-range difference is not within the error range. On the other hand, when the difference in pseudo distance is zero, the determination processing unit 114 determines that the multipath is not affected. Further, the determination processing unit 114 may determine that it is not affected by the multipath when the difference in the pseudo distance is within the error range. The determination processing unit 114 inputs a determination result on whether or not it is affected by the multipath to the positioning calculation unit 116.

  The positioning calculation unit 116 is connected to the pseudo distance difference calculation unit 112 and the determination processing unit 114. The positioning calculation unit 116 calculates the current position of the GNSS satellite in the world coordinate system based on the satellite orbit information of the navigation message. Since the GNSS satellite 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 GNSS satellite is an elliptical motion with the earth's center of gravity as one focal point, and the position of the GNSS satellite on the orbital plane can be calculated by sequentially calculating the Kepler equation. In addition, the position of the GNSS satellite shall be converted to a three-dimensional rotational coordinate from the position of the GNSS satellite on the orbital plane in consideration of the rotational relationship between the orbital plane of the GNSS satellite and the equatorial plane of the world coordinate system. It is obtained by. The world coordinate system is defined by an X axis and a Y axis that are orthogonal to each other within the equator plane, and a Z axis that is orthogonal to both axes with the center of gravity of the earth as the origin.

  The positioning calculation unit 116 measures the position of the GNSS receiver 100 based on the calculation result of the satellite position and the calculation result of the pseudo distance ρ input from the pseudo distance difference calculation unit 112. The positioning calculation unit 116 measures the position of the GNSS receiving apparatus 100 based on the calculation result of the pseudo distance ρ when the determination processing unit 114 determines that it is not affected by the multipath. Then, the positioning calculation unit 116 inputs the positioning calculation result to the position calculation processing unit 120. In addition, the positioning calculation unit 116 stops the positioning calculation when the determination processing unit 114 determines that it is affected by the multipath. The positioning calculation unit 116 may input to the position calculation processing unit 120 that it is affected by the multipath when the determination processing unit 114 determines that it is affected by the multipath.

  In addition, even when there is a GNSS satellite that is determined to be affected by the multipath by the determination processing unit 114, the positioning calculation unit 116 is not affected by the multipath from radio waves from other GNSS satellites. When the positioning calculation is possible, the positioning calculation may be performed and the positioning calculation result may be input to the position calculation processing unit 120.

  The position of the GNSS receiver 100 may be derived on the principle of triangulation using the respective pseudoranges and satellite positions obtained for the three GNSS satellites 100. In this case, since the pseudo distance includes a clock error, the clock error component is removed using the pseudo distance and the satellite position obtained for the fourth GNSS satellite 100.

  Note that the positioning method of the position of the GNSS satellite 100 is not limited to such independent positioning, 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 GNSS receiver 100 is measured using a single phase difference, a double phase difference, or the like of pseudoranges obtained by the fixed station and the GNSS receiver 100, respectively.

  The INS position estimation unit 118 estimates the position of the GNSS receiver 100 from information other than information from the GNSS. For example, the INS position estimation unit 118 integrates the movement of the GNSS receiving apparatus 100 based on the GNSS receiving apparatus 100 itself called IMU or an acceleration detector mounted on a moving body on which the GNSS receiving apparatus 100 is mounted. By doing so, the position may be estimated.

  FIG. 5 is a functional block diagram showing the INS position estimation unit 118.

  The INS position estimation unit 118 includes a sensor 1182 and a position estimation unit 1184.

  The sensor 1182 inputs information obtained from other than the GNSS to the position estimation unit 1184. The sensor 1182 includes, for example, an acceleration sensor, an angular acceleration sensor, a geomagnetic sensor (orientation sensor), and the like. The sensor 1182 is preferably a sensor that can obtain data for determining the position of the GNSS receiver 100 without using radio waves from a GNSS satellite. For example, the sensor 1182 inputs the acceleration detected by the acceleration sensor, the angular acceleration detected by the angular acceleration sensor, and the azimuth detected by the geomagnetic sensor to the position estimation unit 1184.

  The position estimation unit 1184 is connected to the sensor 1182. The position estimation unit 1184 estimates the position of the GNSS receiver 100 based on the information input by the sensor 1182. The position estimation unit 1184 may obtain the speed by integrating the acceleration detected by the acceleration sensor, and obtain the moving distance of the GNSS receiver 100 by integrating the speed. The position estimation unit 1184 may be an inertial navigation device. The position estimation unit 1184 inputs the position estimation result of the GNSS receiver 100 to the position calculation processing unit 120.

  The position calculation processing unit 120 is connected to the positioning calculation unit 116 and the INS position estimation unit 118. The position calculation processing unit 120 outputs either the positioning calculation result input by the positioning calculation unit 116 or the position estimation result input by the INS position estimation unit 118. When the positioning calculation result is input from the positioning calculation unit 116, the position calculation processing unit 120 inputs the positioning calculation result to the map mapping processing unit 122. The position calculation processing unit 118 also includes the positioning calculation unit 116. When the positioning calculation result is not input by, the position estimation result input by the INS position estimation unit 118 is input to the map mapping processing unit 122. The position calculation processing unit 120 inputs the position estimation result input by the INS position estimation unit 118 to the map mapping processing unit 122 when the positioning calculation unit 116 inputs that it is affected by multipath. It may be. When the positioning calculation result is input, the positioning calculation result is input to the map mapping processing unit 122. When the positioning calculation result is not input, the position estimation result is input to the map mapping processing unit 122. Since the position information to be output can be switched to the position estimation result by INS before the accuracy is lowered, the accuracy of the position information can be maintained.

  The map matching processing unit 122 is connected to the position calculation processing unit 120 and the map DB 124. The map matching processing unit 122 performs matching between the map information input by the map DB 124 and the position of the GNSS receiver 100 input by the position calculation processing unit 120. For example, the map matching processing unit 122 corrects the position of the GNSS receiver 100 based on the map information. For example, when the map information input by the map DB 124 is mapped to the position of the GNSS receiver 100 input by the position calculation processing unit 120, the map information of the position is not appropriate. Correct the position. For example, when the position is not on the road, the position is corrected to be on the road. The map matching processing unit 122 outputs the corrected position information.

  The map DB 124 stores map information.

(Positioning method)
FIG. 6 shows a positioning method in the GNSS receiver 100 according to the present embodiment.

The GNSS receiver 100 receives positioning signals from GNSS satellites using a plurality of antennas (step S602). Antenna 102 ₁ and 102 ₂ receives the positioning signals from GNSS satellites.

The GNSS receiver 100 obtains a pseudo distance based on the positioning signal received in step S602 (step S604). Pseudorange calculation section 110 ₁ and 110 _2, from the code phase correlation value of the C / A code replica signal for the C / A code has a peak, respectively obtaining pseudorange A and pseudorange B.

The GNSS receiver 100 obtains a pseudo-range difference corresponding to the positioning signal received by each antenna obtained in step S604 (step S606). Pseudorange difference calculation unit 112, a pseudo distance A input by the pseudorange calculation unit 110 _1, based on the pseudo-range B input by the pseudorange calculation unit 110 _2, the pseudo distance A and the pseudo distance B Calculate the difference.

  The GNSS receiving apparatus 100 determines whether the pseudo-range difference obtained in step S606 is within an error range or ideally zero (step S608). The determination processing unit 114 determines whether the radio wave from the GNSS satellite corresponding to the pseudo distance is affected by the multipath based on the pseudo distance difference input by the pseudo distance difference calculation unit 112. The determination processing unit 114 determines that it is affected by multipath when the difference in pseudo distance is a value larger than zero. On the other hand, when the difference in pseudo distance is zero, the determination processing unit 114 determines that there is no influence of multipath.

  When the difference in pseudo distance is within the error range (step S608: YES), the GNSS receiver 100 performs positioning calculation (step S610). The positioning calculation unit 116 measures the position of the GNSS receiver 100 based on the calculation result of the satellite position and the calculation result of the pseudo distance ρ input from the pseudo distance difference calculation unit 112.

  Moreover, the GNSS receiver 100 estimates the position of the GNSS receiver 100 based on information other than GNSS (step S612). The INS position estimation unit 118 estimates the position of the GNSS receiver 100 based on the acceleration detected by the acceleration sensor, the angular acceleration detected by the angular acceleration sensor, the azimuth detected by the geomagnetic sensor, and the like.

  When the pseudorange difference is not within the error range (step S608: NO) and when the positioning calculation is performed in step S610, the GNSS receiving apparatus 100 obtains the position of the GNSS receiving apparatus 100 after the positioning calculation. (Step S614). When the positioning calculation result is input by the positioning calculation unit 116, the position calculation processing unit 120 inputs the positioning calculation result to the map matching processing unit 122 as position information. When the positioning calculation result is not input by the positioning calculation unit 116, the position calculation processing unit 120 inputs the position estimation result input by the INS position estimation unit 118 as position information to the map matching processing unit 122.

  The GNSS receiver 100 corrects the position obtained in step S614 by map matching processing (step S616). The map matching processing unit 122 performs a matching process between the map information input by the map DB 124 and the position information input by the position calculation processing unit 120, and corrects the position information as necessary.

  The order between steps S602 to S610 and step S612 may be the first, or may be performed simultaneously, in other words, in parallel.

  According to the present embodiment, by arranging a plurality of antennas so that a phase difference occurs between a direct wave and a reflected wave in a state where the GNSS receiver captures a positioning signal from the same GNSS satellite, When the GNSS receiver is located in a multipath environment, pseudoranges calculated based on radio waves (combined waves) received by the plurality of antennas can be different from each other.

  In addition, when it is determined that it is affected by multipath, by outputting the position information estimated based on information other than the positioning signal from the GNSS satellite, before the accuracy of the positioning calculation result decreases Since it is possible to switch to the position estimation result by INS, the accuracy of the position information can be maintained.

  In addition, by having a pseudo-range difference calculation unit that calculates a pseudo-range difference corresponding to each antenna, it is determined that a positioning signal from a GNSS satellite is affected by a multipath based on the pseudo-range difference. be able to.

  According to the present embodiment, by positioning a plurality of antennas in a direction perpendicular to the traveling direction of the GNSS receiver, the GNSS receiver has captured a positioning signal from the same GNSS satellite Thus, a phase difference can be generated between the direct wave and the reflected wave. As a result, it is possible to improve the accuracy of detecting a multipath.

  According to the present embodiment, the GNSS reception is performed by arranging a plurality of antennas in a direction perpendicular to the traveling direction of the GNSS receiver, with a separation of 1/4 to 1/2 of the wavelength of the positioning signal. The phase difference between the direct wave and the reflected wave can be maximized with the device capturing the positioning signal from the same GNSS satellite. As a result, the accuracy of detecting a multipath can be further improved.

  According to the present embodiment, when the difference obtained by the pseudo-range difference calculation unit is zero, the determination unit determines that the multipath is not affected by determining that the difference is not affected by the multipath. Can be judged.

(Second embodiment)
(GNSS receiver)
FIG. 7 shows a GNSS receiver according to the present embodiment.

The GNSS receiver according to the present embodiment is different from the above GNSS receiver in the arrangement of a plurality of antennas. Among the plurality of antennas, at least three antennas are arranged so that a plane can be formed by the three antennas. In other words, the three antennas are not arranged in a straight line. For example, when viewed from above the GNSS receiver, the three antennas are arranged in a triangle. By arranging so that a plane can be formed by three antennas, the direct wave and the reflected wave received between at least two antennas are independent of the incident direction of the reflected wave received by the GNSS receiver. There is a phase difference between them. From the viewpoint of increasing the phase difference between the direct wave and the reflected wave, the antennas are arranged in the direction perpendicular to the traveling direction of the GNSS receiver 100, and the antennas are arranged apart from each other by the antenna interval R. It is preferable to do this. Specifically, the antennas 102 ₁ , 102 ₂ , and 102 ₃ are arranged so that the directivities thereof are perpendicular to the traveling direction of the GNSS receiver 100. For example, the antenna interval R is preferably about 1/4 to 1/2 of the wavelength of a radio wave (carrier wave) for positioning from the GNSS satellite. Regardless of the incident direction of the reflected wave received by the GNSS receiver, multipath in all directions is detected by a phase difference between the direct wave and the reflected wave received between at least two antennas. it can.

  The positioning method in the GNSS receiver 100 according to the present embodiment is the same as the positioning method described with reference to FIG.

  According to the present embodiment, at least three of the plurality of antennas are arranged so that a plane can be formed by the three antennas, regardless of the incident direction of the radio wave from the GNSS satellite, Multipath in all directions can be detected.

(Third embodiment)
(GNSS receiver)
FIG. 8 shows a GNSS receiver according to the present embodiment.

The GNSS receiver according to the present embodiment has an antenna control unit 126 in the GNSS receiver described with reference to FIG. The antenna controller 126 receives correlation calculation results from the correlators 108 ₁ and 108 ₂ .

The antenna control unit 126 controls the interval and / or direction of at least two antennas among the plurality of antennas. Antenna control unit 126 is connected to the antenna 102 ₁ and 102 _2. For example, as shown in FIG. 9, the two antennas may be installed on a rotating body. The antenna control unit 126 variably controls the direction of the antenna by rotating the rotator based on the correlation calculation result input by the correlators 108 ₁ and 108 ₂ . For example, the antenna control unit 126 variably controls the direction of the antenna based on the correlation calculation result input by the correlators 108 ₁ and 108 ₂ so that the phase difference that is the peak of the correlation value is maximized. You may do it.

Further, the antenna control unit 126 changes the antenna interval based on the correlation calculation result input by the correlators 108 ₁ and 108 ₂ . For example, the antenna control unit 126 may change the antenna interval based on the correlation calculation result input by the correlators 108 ₁ and 108 ₂ so that the phase difference at the peak of the correlation value is maximized. May be. That is, the antenna control unit 126 changes the antenna interval and / or the antenna direction so that the phase difference between the signals from the two antennas becomes the largest. By changing the antenna interval and / or the antenna direction so that the phase difference between the signals from the two antennas becomes the largest, at least regardless of the incident direction of the composite wave received by the GNSS receiver 100. A multipath in all directions can be detected by generating a phase difference between signals from two antennas. By changing the antenna interval and / or antenna direction so that the phase difference between the signals from the two antennas becomes the largest, regardless of the elevation angle at which the combined wave received by the GNSS receiver 100 is incident, A multipath at all elevation angles can be detected by generating a phase difference between synthesized waves received by at least two antennas.

  The positioning method in the present GNSS receiver 100 is the same as the positioning method described with reference to FIG. 6, in the state where a positioning signal from the same GNSS satellite is captured before step S <b> 602. Control is performed to change the intervals and / or directions of the plurality of antennas included in the GNSS receiver so that a phase difference occurs.

  According to the present embodiment, by changing the antenna interval and / or the antenna direction, multipaths in all directions and all elevation angles can be detected regardless of the incident direction and elevation angle of the signal from the GNSS satellite.

(Fourth embodiment)
(GNSS receiver)
FIG. 10 shows a GNSS receiver according to the present embodiment.

  The GNSS receiver 100 according to the present embodiment has a plurality of GNSS receivers. Each GNSS receiver has one antenna. In FIG. 10, the high frequency processing unit 104 that should be provided corresponding to each antenna is omitted. In FIG. 10, the position calculation processing unit 120, the INS position estimation unit 118, the map matching processing unit 122, and the map DB 124 to be connected to the positioning calculation unit 116 are omitted.

In the GNSS receiver 100, the positioning calculation unit 116 is connected to the pseudo distance calculation unit 110. The pseudo distances calculated by the pseudo distance calculation units 110 ₁ and 110 ₂ are input to the pseudo distance difference calculation unit 112, and the pseudo distances calculated by the pseudo distance calculation unit 110 ₁ are input to the positioning calculation unit 116.

Pseudorange difference calculation unit 112, a pseudo distance A input by the pseudorange calculation unit 110 _1, based on the pseudo-range B input by the pseudorange calculation unit 110 _2, the pseudo distance A and the pseudo distance B Calculate the difference. The pseudo distance difference calculation unit 112 inputs the pseudo distance difference to the determination processing unit 114.

Positioning calculation unit 116 calculates the placement of the GNSS satellites based on the positioning signal corresponding to the pseudo distance A input by the pseudorange calculation unit 110 _1, inputs the arrangement of the GNSS satellite pseudorange difference estimation unit 128 . Here, the pseudo distance A is a pseudo distance obtained based on a positioning signal from each GNSS satellite and may be plural.

Pseudorange difference estimation unit 128 is connected to the positioning computation unit 116, based on the distance between the arrangement of the GNSS satellites that are input by the positioning operation unit 116 and the antenna 102 ₁ and 102 _2, the pseudo distance difference Estimate the theoretical value. The pseudo distance difference estimation unit 120 inputs a theoretical value of the estimated pseudo distance difference to the determination processing unit 114.

  The determination processing unit 114 is connected to the pseudo distance difference calculating unit 112 and the pseudo distance difference estimating unit 120, and the pseudo distance difference input by the pseudo distance difference calculating unit 112 and the pseudo distance difference estimating unit 128. Based on the theoretical value of the distance difference, it is determined whether the radio wave from the GNSS satellite corresponding to the pseudorange is affected by the multipath. The determination processing unit 114 determines that there is a multipath effect when the pseudo-range difference and the theoretical value of the pseudo-range difference differ by more than the error range. Ideally, the determination processing unit 114 determines that it is affected by multipath when the pseudo-range difference and the theoretical value of the pseudo-range difference are different values. On the other hand, the determination processing unit 114 is not affected by the multipath when the pseudo-range difference and the theoretical value of the pseudo-range difference are not different or within the error range even if they are different. judge. The determination processing unit 114 outputs a determination result as to whether or not it is affected by multipath. The determination result may be input to the positioning calculation unit 116. The positioning calculation unit 116 performs the positioning calculation as described above based on the determination result. For example, the positioning calculation unit 116 performs the positioning calculation as described above when not affected by multipath. The positioning calculation unit 116 inputs the positioning calculation result to a position calculation processing unit (not shown).

(Positioning method)
FIG. 11 shows a positioning method in the GNSS receiver 100 according to the present embodiment.

The GNSS receiver 100 receives positioning signals from GNSS satellites using a plurality of antennas (step S1102). Antenna 102 ₁ and 102 ₂ receives the positioning signals from GNSS satellites.

The GNSS receiver 100 obtains a pseudo distance based on the positioning signal received in step S1102 (step S1104). Pseudorange calculation section 110 ₁ and 110 _2, from the code phase correlation value of the C / A code replica signal for the C / A code has a peak, respectively obtaining pseudorange A and pseudorange B.

The GNSS receiver 100 obtains a pseudo-range difference corresponding to the positioning signal received by each antenna obtained in step S1104 (step S1106). Pseudorange difference calculation unit 112, a pseudo distance A input by the pseudorange calculation unit 110 _1, based on the pseudo-range B input by the pseudorange calculation unit 110 _2, the pseudo distance A and the pseudo distance B Calculate the difference.

The GNSS receiver 100 calculates the arrangement of GNSS satellites based on the positioning signal corresponding to the pseudorange obtained in step S1104 (step S1108). Positioning operation unit 116, based on the positioning signal corresponding to the pseudo distance A input by the pseudorange calculation unit 110 ₁ calculates the arrangement of the GNSS satellites.

The GNSS receiver 100 estimates a pseudo-range difference based on the arrangement of the GNSS satellites obtained in step S1108 and the distance between the antennas (step S1110). Pseudorange difference estimation unit 128, the arrangement of the GNSS satellites that are input by the positioning calculation unit 116, based on the distance between the antenna 102 ₁ and 102 _2, and estimates the theoretical value of the difference between the pseudorange.

  The GNSS receiver 100 determines whether the difference between the pseudorange difference obtained in step S1106 and the pseudorange difference estimated in step S1110 is within an error range or ideally zero. (Step S1112). The determination processing unit 114 corresponds to the pseudo distance based on the pseudo distance difference input by the pseudo distance difference calculating unit 112 and the theoretical value of the pseudo distance difference input by the pseudo distance difference estimating unit 128. Determine whether the radio waves from the GNSS satellite are affected by multipath.

When the difference between the pseudo-range difference and the estimated value of the pseudo-range difference is within the error range (step S1012: YES), the GNSS receiver 100 performs a positioning calculation (step S1114). Positioning operation unit 116, the calculation result of the satellite position, based on the calculation result of the pseudorange ρ input from the pseudo distance calculator 110 ₁ and measures the position of the GNSS receiver 100.

  The GNSS receiver 100 estimates the position of the GNSS receiver 100 based on information other than GNSS (step S1116). The INS position estimation unit 118 estimates the position of the GNSS receiver 100 based on the acceleration detected by the acceleration sensor, the angular acceleration detected by the angular acceleration sensor, the azimuth detected by the geomagnetic sensor, and the like.

  When the difference between the pseudo-range difference and the estimated value of the pseudo-range difference is not within the error range (step S1112: NO) and when the positioning calculation is performed in step S1114, the GNSS receiving apparatus after the positioning calculation 100 obtains the position of the GNSS receiver 100 (step S1118). When the positioning calculation result is input by the positioning calculation unit 116, the position calculation processing unit 120 inputs the positioning calculation result to the map matching processing unit 122 as position information. When the positioning calculation result is not input by the positioning calculation unit 116, the position calculation processing unit 120 inputs the position estimation result input by the INS position estimation unit 118 as position information to the map matching processing unit 122.

  The GNSS receiver 100 corrects the position obtained in step S1118 by map matching processing (step S1120). The map matching processing unit 122 performs a matching process between the map information input by the map DB 124 and the position information input by the position calculation processing unit 120, and corrects the position information as necessary.

  The order between steps S1102 to S1114 and step S1116 may be either, or may be performed simultaneously, in other words, in parallel.

  According to the present embodiment, even when the interval between the antennas is set arbitrarily, it can be determined that it is affected by multipath. In the first embodiment described above, it is preferable that the antenna interval R is 1/4 to 1/2 of the wavelength of the radio wave from the GNSS satellite. In the present embodiment, the antenna interval R does not have to be 1 / 4-1 / 2 of the wavelength of the radio wave from the GNSS satellite. Therefore, the antenna interval can be set arbitrarily.

(Fifth embodiment)
(GNSS receiver)
FIG. 12 shows a GNSS receiver according to the present embodiment.

The GNSS receiver 100 according to the present embodiment has a plurality of GNSS receivers. Each GNSS receiver has one antenna. In FIG. 12, the high frequency processing unit to be provided for each antenna is omitted. FIG. 12 shows a portion for detecting a multipath in the above-described embodiment. In other words, the processing after the positioning calculation processing is omitted. In addition, each GNSS receiver includes correlation value difference calculation units 130 ₁ and 130 ₂ . Since the correlation value difference calculation units 130 ₁ and 130 ₂ have the same function, they will be described as the correlation value difference calculation unit 130.

  The correlator 108 performs correlation processing by shifting the phase of the C / A code replica signal with respect to the L1 band C / A code. As a result of the correlation processing, a graph indicating the correlation value indicated by an isosceles triangle having the maximum value of the correlation value as a vertex in theory is obtained at the coordinates with the phase as the horizontal axis and the correlation value as the vertical axis. The correlator 108 uses a correlation value indicated by an isosceles triangle having the maximum value of the correlation value as a vertex, and is delayed by a phase (EARLY) advanced by a certain amount with respect to the phase (PUNCTUAL) considered to be the center. The phase (LATE) replica C / A code is generated, and the correlation with EARLY and LATE is obtained for the C / A code in the L1 band. Correlator 108 controls the phase of the replica C / A code so that the correlation values with EARLY and LATE are equal. Correlator 108 estimates that the intermediate phase between EARLY and LATE when the correlation value between EARLY and LATE is equal is the phase of the C / A code in the L1 band. However, in a multipath environment, the isosceles triangle whose apex is the maximum correlation value is broken, and the phase of the C / A code cannot be estimated accurately. If the phase of the received C / A code cannot be estimated accurately, the correlator 108 performs correlation processing by narrowing the phase difference between EARLY and LATE (narrow correlator).

Correlators 108 ₁ and 108 ₂ acquire / track the same GNSS satellite. Correlators 108 ₁ and 108 ₂ obtain the phase of EARLY, obtain the correlation value in the EARLY (hereinafter referred to as EARLY correlation value) and the phase of LATE, and correlate in the LATE (hereinafter referred to as LATE correlation value). the respective inputs to the correlation value difference calculating section 130 ₁ and 130 _2. In FIG. 12, the EARLY correlation value is indicated by E, and the LATE correlation value is indicated by L.

13 and 14 show examples of correlation characteristics obtained by the correlators 108 ₁ and 108 ₂ . For example, the correlation value difference calculating section 130 ₁ and 130 _2, based on the correlation characteristics shown in FIGS. 13 and 14, obtains a difference EL between the EARLY correlation value and LATE correlation value. A correlation value difference calculated by the correlation value difference calculating section 130 ₁ is referred to as correlation value difference A, referred to as correlation value difference calculated by the correlation value difference calculating section 130 ₂ and the correlation value difference B. The correlation value difference calculation units 130 ₁ and 130 ₂ input the correlation value differences A and B to the determination processing unit 114.

The determination processing unit 114 is connected to the correlation value difference calculation units 130 ₁ and 130 ₂ . Determination processing unit 114, whether based on the correlation value difference A and B input by the correlation value difference calculating section 130 ₁ and 130 _2, radio waves from the GNSS satellites corresponding to the correlation values are affected by a multipath judge. When the difference between the correlation value difference A and the correlation value difference B is zero, the determination processing unit 114 determines that the multipath is not affected. The determination processing unit 114 may determine that the difference between the correlation value difference A and the correlation value difference B is not affected by the multipath when the difference is within the error range. On the other hand, when the difference between the correlation value difference A and the correlation value difference B is not zero, the determination processing unit 114 determines that it is affected by multipath. The determination processing unit 114 may determine that the difference between the correlation value difference A and the correlation value difference B is larger than the error range and is affected by multipath. The determination processing unit 114 outputs a determination result as to whether or not it is affected by multipath. The determination result may be input to the positioning calculation unit 116 (not shown). The positioning calculation unit 116 performs the positioning calculation as described above based on the determination result. For example, the positioning calculation unit 116 performs the positioning calculation as described above when not affected by multipath. The positioning calculation unit 116 inputs the positioning calculation result to the position calculation processing unit 120 (not shown).

(Positioning method)
FIG. 15 shows a positioning method in the GNSS receiver 100 according to the present embodiment.

The GNSS receiver 100 receives positioning signals from GNSS satellites using a plurality of antennas (step S1502). Antenna 102 ₁ and 102 ₂ receives the positioning signals from GNSS satellites.

Based on the positioning signal received in step S1502, the GNSS receiver 100 correlates the C / A code included in the positioning signal and the replica signal of the C / A code, and the correlation value is maximized. A phase advanced by a certain amount and a phase delayed by a certain amount are obtained with respect to the phase (step S1504). Correlators 108 ₁ and 108 ₂ acquire / track the same GNSS satellite. Correlators 108 ₁ and 108 ₂ determine the phase at EARLY and the phase at LATE.

The GNSS receiver 100 obtains a difference between correlation values corresponding to the phase advanced by a certain amount and the phase delayed in step S1504 for each antenna (step S1506). Correlators 108 ₁ and 108 ₂ input the EARLY correlation value and the LATE correlation value to correlation value difference calculating sections 130 ₁ and 130 ₂ , respectively. Correlation value difference calculating section 130 ₁ and 130 ₂ obtains a difference EL between the EARLY correlation value and LATE correlation value.

The GNSS receiving apparatus 100 determines whether the difference between the correlation values obtained for each antenna in step S1506 is equal or within the error range even if they are different (step S1508). Determination processing unit 114, whether based on the correlation value difference A and B input by the correlation value difference calculating section 130 ₁ and 130 _2, radio waves from the GNSS satellites corresponding to the correlation values are affected by a multipath judge.

  When the difference of the correlation value calculated | required for every antenna is equal (step S1508: YES), the GNSS receiver 100 performs a positioning calculation (step S1510). The positioning calculation unit 116 measures the position of the GNSS receiver 100 based on the satellite position calculation result and the pseudo distance ρ calculation result.

  Also, the GNSS receiver 100 estimates the position of the GNSS receiver 100 based on information other than GNSS (step S1512). The INS position estimation unit 118 estimates the position of the GNSS receiver 100 based on the acceleration detected by the acceleration sensor, the angular acceleration detected by the angular acceleration sensor, the azimuth detected by the geomagnetic sensor, and the like.

  When the difference of the correlation value calculated | required for every antenna is not equal (step S1508: NO) and when a positioning calculation is performed by step S1510, after this positioning calculation, the GNSS receiving apparatus 100 is the said GNSS receiving apparatus 100. Is determined (step S1514). When the positioning calculation result is input by the positioning calculation unit 116, the position calculation processing unit 120 inputs the positioning calculation result to the map matching processing unit 122 as position information. When the positioning calculation result is not input by the positioning calculation unit 116, the position calculation processing unit 120 inputs the position estimation result input by the INS position estimation unit 118 as position information to the map matching processing unit 122.

  The GNSS receiving apparatus 100 corrects the position obtained in step S1514 by map matching processing (step S1516). The map matching processing unit 122 performs a matching process between the map information input by the map DB 124 and the position information input by the position calculation processing unit 120, and corrects the position information as necessary.

  The order between steps S1502 to S1510 and step S1512 may be either first, or in other words, may be performed in parallel.

  According to the present embodiment, the determination can be made based on the output of the correlator without calculating the pseudo distance in order to determine whether or not it is affected by the multipath. Since the determination can be made based on the output of the correlator, it is possible to reduce the amount of calculation for determining whether the multipath is received. In addition, the scale of hardware for determining whether or not it is affected by multipath can be reduced.

(Sixth embodiment)
(GNSS receiver)
FIG. 16 shows a GNSS receiver according to the present embodiment.

  The GNSS receiver 100 according to the present embodiment does not include the correlation value difference calculation unit 130 in the GNSS receiver described with reference to FIG. FIG. 16 shows a portion for detecting multipath in the above-described embodiment. In other words, the processing after the positioning calculation processing is omitted.

The correlator 108 performs correlation processing by shifting the phase of the C / A code replica signal with respect to the L1 band C / A code. Correlators 108 ₁ and 108 ₂ acquire / track the same GNSS satellite. Correlators 108 ₁ and 108 ₂ input correlation values in PUNCTUAL (hereinafter referred to as PUNCTUAL correlation values) to determination processing unit 114. In FIG. 16, the PUNCTUAL correlation value is indicated by P. For example, the correlators 108 ₁ and 108 ₂ obtain PUNCTUAL correlation values based on the correlation characteristics as shown in FIGS. The PUNCTUAL correlation value calculated by the correlator 108 ₁ is called a PUNCTUAL correlation value A, and the PUNCTUAL correlation value calculated by the correlator 108 ₂ is called a PUNCTUAL correlation value B. Correlators 108 ₁ and 108 ₂ input PUNCTUAL correlation values A and B to determination processing unit 114.

Determination processing unit 114 determines whether, based on PUNCTUAL correlation values A and B input by the correlators 108 ₁ and 108 _2, radio waves from GNSS satellites corresponding to the correlation value is affected by a multipath . When the difference between the PUNCTUAL correlation value A and the PUNCTUAL correlation value B is zero, the determination processing unit 114 determines that the multipath is not affected. Further, the determination processing unit 114 may determine that it is not affected by the multipath when the difference between the PUNCTUAL correlation value A and the PUNCTUAL correlation value B is within an error range. On the other hand, when the difference between the PUNCTUAL correlation value A and the PUNCTUAL correlation value B is not zero, the determination processing unit 114 determines that it is affected by multipath. Further, the determination processing unit 114 may determine that it is affected by multipath when the difference between the PUNCTUAL correlation value A and the PUNCTUAL correlation value B is larger than the error range. The determination processing unit 114 outputs a determination result as to whether or not it is affected by multipath. The determination result may be input to the positioning calculation unit 116. The positioning calculation unit 116 performs the positioning calculation as described above based on the determination result. For example, the positioning calculation unit 116 performs the positioning calculation as described above when not affected by multipath. The positioning calculation unit 116 inputs the positioning calculation result to the position calculation processing unit 120 (not shown).

(Positioning method)
A positioning method in the GNSS receiver 100 according to the present embodiment will be described with reference to FIG.

The GNSS receiver 100 receives positioning signals from GNSS satellites using a plurality of antennas (step S1902). Antenna 102 ₁ and 102 ₂ receives the positioning signals from GNSS satellites.

Based on the positioning signal received in step S1902, the GNSS receiver 100 correlates the C / A code included in the positioning signal with the replica signal of the C / A code, and maximizes the correlation value. The phase is obtained (step S1904). Correlators 108 ₁ and 108 ₂ acquire / track the same GNSS satellite. Correlators 108 ₁ and 108 ₂ determine the phase at PUNCTUAL.

The GNSS receiver 100 obtains a correlation value corresponding to the phase at which the correlation value obtained in step S1904 is maximized for each antenna (step S1906). Correlators 108 ₁ and 108 ₂ obtain PUNCTUAL correlation values corresponding to the phases in PUNCTUAL. The correlators 108 ₁ and 108 ₂ input the PUNCTUAL correlation values A and B to the determination processing unit 114, respectively.

  The GNSS receiver 100 determines whether or not the PUNCTUAL correlation values obtained for each antenna in step S1906 are equal or different even if they are different (step S1908).

  When the PUNCTUAL correlation value calculated | required for every antenna is equal (step S1908: YES), the GNSS receiver 100 performs a positioning calculation (step S1910). The positioning calculation unit 116 measures the position of the GNSS receiver 100 based on the satellite position calculation result and the pseudo distance ρ calculation result.

  Moreover, the GNSS receiver 100 estimates the position of the GNSS receiver 100 based on information other than GNSS (step S1912). The INS position estimation unit 118 estimates the position of the GNSS receiver 100 based on the acceleration detected by the acceleration sensor, the angular acceleration detected by the angular acceleration sensor, the azimuth detected by the geomagnetic sensor, and the like.

  When the PUNCTUAL correlation values obtained for each antenna are not equal (step S1908: NO) and when the positioning calculation is performed in step S1910, after the positioning calculation, the GNSS receiving apparatus 100 The position is obtained (step S1914). When the positioning calculation result is input by the positioning calculation unit 116, the position calculation processing unit 120 inputs the positioning calculation result to the map matching processing unit 122 as position information. When the positioning calculation result is not input by the positioning calculation unit 116, the position calculation processing unit 120 inputs the position estimation result input by the INS position estimation unit 118 as position information to the map matching processing unit 122.

  The GNSS receiver 100 corrects the position obtained in step S1914 by map matching processing (step S1916). The map matching processing unit 122 performs a matching process between the map information input by the map DB 124 and the position information input by the position calculation processing unit 120, and corrects the position information as necessary.

  The order between step S1902-S1910 and step S1912 may be the first, or may be performed simultaneously, in other words, in parallel.

  According to the present embodiment, the determination can be made based on the output of the correlator without calculating the pseudo distance in order to determine whether or not it is affected by the multipath. Furthermore, the determination can be made based on the output of the correlator without calculating the difference of the correlation values in order to determine whether or not it is affected by the multipath. Since the determination can be made based on the output of the correlator, it is possible to reduce the amount of calculation for determining whether the multipath is received. In addition, the scale of hardware for determining whether or not it is affected by multipath can be reduced.

(Seventh embodiment)
FIG. 20 shows a GNSS receiver according to this embodiment. In FIG. 20, in the above-described embodiment, a correlator portion is shown, and portions other than the correlator are omitted.

  The GNSS receiver 100 according to the present embodiment shares the acquisition circuits included in the plurality of correlators 108 provided corresponding to each antenna among the plurality of correlators in the GNSS receiver described above.

  The GNSS receiver 100 has a plurality of antennas 102. The GNSS receiving apparatus 100 includes a plurality of correlators 108 that correspond one-to-one to the plurality of antennas. Each correlator 108 has a tracking circuit 1084. In addition, at least one correlator out of the plurality of correlators 108 has an acquisition circuit 1082. The acquisition circuit 1082 need not be included in all correlators, but is included in a number of correlators less than the number of correlators. That is, a correlator having a capture circuit and a correlator not having a capture circuit may be mixed. In the present embodiment, a case where the GNSS receiver 100 has two antennas will be described as in the above-described embodiment, but the present invention can also be applied to a case where there are three or more antennas.

The acquisition circuit 1082 detects the Doppler frequency of the digital intermediate frequency signal input by the high-frequency processing unit 104 (not shown) and the GNSS satellite number. For example, the acquisition circuit 1082 generates a carrier replica signal. Then, the acquisition circuit 1082 measures the Doppler shifted component by performing a correlation operation between the generated carrier replica signal and the received carrier. As the GNSS satellite number, a PRN number corresponding to the C / A code pattern may be used. The acquisition circuit 1082 inputs the acquired GNSS satellite number and the measured Doppler frequency to the tracking circuit 1084 ₁ of the correlator 108 ₁ including the acquisition device 1082. Further, acquisition circuit 1082, a GNSS satellite number captured, the Doppler frequency is measured and input to the tracking circuit 1084 _{and second} correlators 108 ₂ other than the correlators 108 ₁ including the capture device 1082.

  The tracking circuit 1084 obtains a C / A code corresponding to the GNSS satellite number input by the acquisition circuit 1082. Then, the tracking circuit 1084 adjusts the timing using the Doppler frequency input by the acquisition circuit 1082, so that the C / A code included in the positioning signal from the GNSS satellite of the corresponding C / A code corresponding to the GNSS satellite number is obtained. And the phase where the correlation value reaches a peak is tracked.

  According to the present embodiment, since it is not necessary to provide the acquisition circuit in all the correlators, the circuit scale of the GNSS receiver can be reduced. In addition, power consumption in the GNSS receiver can be reduced.

(Eighth embodiment)
(GNSS receiver)
FIG. 21 shows a GNSS receiver according to the present embodiment. In FIG. 21, the correlator part is shown in the above-described embodiment, and parts other than the correlator are omitted.

  The GNSS receiver 100 according to the present embodiment shares a part of the function of the tracking circuit among the correlators in the GNSS receiver described with reference to FIG. In other words, a part of the functions of the acquisition circuit and the tracking circuit included in the plurality of correlators 108 provided corresponding to each antenna are shared between the plurality of correlators.

  The GNSS receiver 100 has a plurality of antennas 102. The GNSS receiving apparatus 100 includes a plurality of correlators 108 that correspond one-to-one to the plurality of antennas. Among the plurality of correlators 108, at least one correlator has an acquisition circuit 1082 and a tracking circuit 1084. The acquisition circuit 1082 and the tracking circuit 1084 do not have to be included in all correlators, but are included in a number of correlators less than the number of correlators. That is, a correlator having the acquisition circuit 1082 and the tracking circuit 1084 and a correlator not having the acquisition circuit 1082 and the tracking circuit 1084 may be mixed. The correlator 108 that does not have the tracking circuit 1084 has a correlation value calculation unit 1086. Here, the correlator having the acquisition circuit 1082 and the correlator having the tracking circuit 1084 may not be the same correlator. Here, a case where the correlator having the acquisition circuit 1082 and the correlator having the tracking circuit 1084 are the same correlator will be described.

The acquisition circuit 1082 detects the Doppler frequency of the digital intermediate frequency signal input by the high-frequency processing unit 104 (not shown) and the GNSS satellite number. For example, the acquisition circuit 1082 generates a carrier replica signal. Then, the acquisition circuit 1082 measures the Doppler-shifted Doppler component by calculating a correlation value between the generated carrier replica signal and the received carrier wave. As the GNSS satellite number, a PRN number corresponding to the C / A code pattern may be used. Acquisition circuit 1082, a GNSS satellite number captured, the Doppler frequency is measured and input to the tracking circuit 1084 of the correlator ₁₀₈₁ including the capture device 1082.

The tracking circuit 1084 obtains a C / A code corresponding to the GNSS satellite number input by the acquisition circuit 1082. Then, the tracking circuit 1084 adjusts the timing using the Doppler frequency input by the acquisition circuit 1082, so that the C / A code included in the positioning signal from the GNSS satellite of the corresponding C / A code corresponding to the GNSS satellite number is obtained. And the phase where the correlation value reaches a peak is tracked. Tracking circuit 1084 inputs the C / A code and the carrier signal tracking, the correlation value calculation unit 1086 included in the other correlator 108 _2.

  The correlation value calculation unit 1086 generates a replica of the positioning signal from the C / A replica code input by the tracking circuit 1084 and the carrier signal. Then, the correlation value calculation unit 1086 obtains a correlation value between the positioning signal from the GNSS satellite and the positioning signal replica.

  According to the present embodiment, since it is not necessary to provide a capturing circuit and a tracking circuit in all correlators, the circuit scale of the GNSS receiver can be reduced. In addition, power consumption in the GNSS receiver can be reduced.

  For convenience of explanation, specific numerical examples will be described to facilitate understanding of the invention. However, unless otherwise specified, these numerical values are merely examples, and any appropriate value may be used.

  Although the present invention has been described above with reference to specific embodiments, each embodiment is merely an example, and those skilled in the art will understand various variations, modifications, alternatives, substitutions, and the like. I will. For convenience of explanation, an apparatus according to an embodiment of the present invention has been described using a functional block diagram, but such an apparatus may be implemented in hardware, software, or a combination thereof. The present invention is not limited to the above-described embodiments, and various variations, modifications, alternatives, substitutions, and the like are included without departing from the spirit of the present invention.

50 wall (reflector)
100 GNSS receiver 102 (102 ₁ , 102 ₂ , 102 ₃ ) Antenna 104 (104 ₁ , 104 ₂ ) High frequency processing unit 106 Signal processing unit 108 (108 ₁ , 108 ₂ ) Correlator 1082 Acquisition circuit 1084 (1084 ₁ , 1084) ₂ ) Tracking circuit 1086 Correlation value calculation unit 110 (110 ₁ , 110 ₂ ) Pseudo distance calculation unit 112 Pseudo distance difference calculation unit 114 Judgment processing unit 116 Positioning calculation unit 118 INS position estimation unit 1182 Sensor 1184 Position estimation unit 120 Position calculation processing Section 122 Map Matching Processing Section 124 Map DB (database)
126 Antenna Control Unit 128 Pseudo Distance Difference Estimation Unit 130 (130 ₁ , 130 ₂ ) Correlation Value Difference Calculation Unit

Claims (7)

A GNSS receiver that performs a positioning operation based on a positioning signal transmitted from a GNSS satellite,
In a state where the GNSS receiver captures a positioning signal from the same GNSS satellite, a plurality of antennas arranged so as to cause a phase difference between the direct wave and the reflected wave,
Using a code included in a positioning signal from the same GNSS satellite received by each antenna, a pseudorange calculation unit for obtaining a pseudorange between the GNSS satellite and the GNSS receiver,
A pseudo-range difference calculation unit for obtaining a difference between the pseudo-ranges obtained by the pseudo-range calculation unit;
A determination unit that determines that a positioning signal from the GNSS satellite is affected by a multipath based on the difference obtained by the pseudorange difference calculation unit;
A position estimation unit that estimates the position of the GNSS receiver based on information other than the positioning signal from the GNSS satellite;
A GNSS receiving apparatus comprising: a position information output unit that outputs position information estimated by the position estimation unit when it is determined that the determination unit is affected by multipath. In the GNSS receiver according to claim 1,
The plurality of antennas are arranged in the direction perpendicular to the traveling direction of the GNSS receiver by being spaced apart by an interval of 1/4 to 1/2 of the wavelength of the positioning signal. In the GNSS receiver according to claim 1 or 2,
The determination unit, when the difference obtained by the pseudo-range difference calculation unit is zero, determines that it is not affected by multipath, wherein the determination unit is a GNSS receiver. A GNSS receiver that performs a positioning operation based on a positioning signal transmitted from a GNSS satellite,
Multiple antennas,
Using a code included in a positioning signal from the same GNSS satellite received by each antenna, a pseudorange calculation unit for obtaining a pseudorange between the GNSS satellite and the GNSS receiver,
A pseudo-range difference calculation unit for obtaining a difference between the pseudo-ranges obtained by the pseudo-range calculation unit;
Calculate the position of the GNSS satellite based on the positioning signal corresponding to each pseudo distance obtained by the pseudo distance calculation unit, and based on the distance between the position of the GNSS satellite and the plurality of antennas, the pseudo distance A pseudo-range difference estimator for estimating the difference between
Based on the pseudorange difference obtained by the pseudorange difference calculation unit and the pseudorange difference estimated by the pseudorange difference estimation unit, the positioning signal from the GNSS satellite is affected by multipath. A determination unit for determining that;
A position estimation unit that estimates the position of the GNSS receiver based on information other than the positioning signal from the GNSS satellite;
A GNSS receiving apparatus comprising: a position information output unit that outputs position information estimated by the position estimation unit when it is determined that the determination unit is affected by multipath. In the GNSS receiver according to claim 4,
When the difference between the pseudo-range difference obtained by the pseudo-range difference calculation unit and the pseudo-range difference estimated by the pseudo-range difference estimation unit is zero, the determination unit determines the influence of multipath. A GNSS receiver characterized in that it is determined not to receive. A positioning method in a GNSS receiver that performs a positioning operation based on a positioning signal transmitted from a GNSS satellite,
In a state where the GNSS receiver captures a positioning signal from the same GNSS satellite, it is from the same GNSS satellite received by a plurality of antennas arranged so that a phase difference occurs between the direct wave and the reflected wave. Using a code included in the positioning signal, a pseudo-range calculation step for obtaining a pseudo-range between the GNSS satellite and the GNSS receiver,
A pseudo distance difference calculating step for obtaining a difference between the pseudo distances obtained by the pseudo distance calculating step;
A determination step of determining that the positioning signal from the GNSS satellite is affected by a multipath based on the difference obtained by the pseudo-range difference calculation step;
Based on information other than positioning signals from GNSS satellites, a position estimation step for estimating the position of the GNSS receiver,
A positioning method, comprising: a position information output step of outputting the position information estimated by the position estimation step when it is determined by the determination step that there is a multipath effect. A positioning method in a GNSS receiver that performs a positioning operation based on a positioning signal transmitted from a GNSS satellite,
A pseudo-range calculation step for obtaining a pseudo-range between the GNSS satellite and the GNSS receiver using a code included in a positioning signal from the same GNSS satellite received by a plurality of antennas of the GNSS receiver; ,
A pseudo distance difference calculating step for obtaining a difference between the pseudo distances obtained by the pseudo distance calculating step;
Calculate the position of the GNSS satellite based on the positioning signal corresponding to each pseudo distance obtained by the pseudo distance calculation step, and based on the distance between the position of the GNSS satellite and the plurality of antennas, the pseudo distance A pseudo-range difference estimation step for estimating a difference between
The positioning signal from the GNSS satellite is affected by the multipath based on the pseudorange difference obtained by the pseudorange difference calculation step and the pseudorange difference estimated by the pseudorange difference estimation step. A determination step for determining that,
Based on information other than positioning signals from GNSS satellites, a position estimation step for estimating the position of the GNSS receiver,
A positioning method, comprising: a position information output step of outputting the position information estimated by the position estimation step when it is determined by the determination step that there is a multipath effect.

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