JP5347942B2 - GNSS receiving apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the accuracy of determination of whether affected by a multipath phenomenon. <P>SOLUTION: A GNSS receiving apparatus for receiving a positioning signal transmitted from a GNSS satellite includes: a plurality of correlators for generating inverse correlation codes with respect to the positioning signal, and performing correlation processing between the inverse correlation codes and the received signal; a control part for controlling correlation processing time durations in the plurality of correlators based on the moving speed of the GNSS receiving apparatus; and a determination part for determining whether the positioning signal from the GNSS satellite is affected by the multipath phenomenon based on correlation characteristics acquired by the plurality of correlators. The plurality of correlators generate inverse correlation codes having different phase differences. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

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

  Satellite navigation (GNSS: Global Navigation Satellite System) is a navigation system that can obtain the flight position of an aircraft in three dimensions. In satellite navigation, the distance from each GNSS satellite is obtained by capturing three navigation satellites (GNSS orbiting satellites) (hereinafter referred to as GNSS satellites) from the aircraft, and the time is indicated by the signal from the fourth navigation satellite. Align. Satellite navigation includes the Global Positioning System (GPS), Galileo, and others.

  For example, the GNSS receiver is mounted on a moving body and measures the position and speed of the moving body. For example, the GNSS receiver receives radio waves from a plurality of GNSS satellites, calculates the distances (pseudo distances) from the plurality of GNSS satellites to the GNSS receiver, and receives the GNSS reception based on the pseudo distances. Measures the moving object equipped with the device.

FIG. 1 shows a positioning method in a GNSS receiver. The position of the GNSS receiver is (X, Y, Z), and the clock error is ΔT. The position of the GNSS satellite 1 is (X ₁ , Y ₁ , Z ₁ ), and the observation distance is ρ ₁ . The position of the GNSS satellite 2 is (X ₂ , Y ₂ , Z ₂ ), and the observation distance is ρ ₂ . The position of the GNSS satellite 3 is (X ₃ , Y ₃ , Z ₃ ), and the observation distance is ρ ₃ . The position of the GNSS satellite 4 is (X ₄ , Y ₄ , Z ₄ ), and the observation distance is ρ ₄ .

  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, when obtaining the position of the GNSS receiver by triangulation, the following equations (1) to (4) are established.

Observation distance ρ ₁ = c · ΔT + √ {(X ₁ -X) ² + (Y ₁ -Y) ² + (Z ₁ -Z) ² } (1)
Observation distance ρ ₂ = c · ΔT + √ {(X ₂ -X) ² + (Y ₂ -Y) ² + (Z ₂ -Z) ² } (2)
Observation distance ρ ₃ = c · ΔT + √ {(X ₃ -X) ² + (Y ₃ -Y) ² + (Z ₃ -Z) ² } (3)
Observation distance ρ ₄ = c · ΔT + √ {(X ₄ -X) ² + (Y ₄ -Y) ² + (Z ₄ -Z) ² } (4)
In Formula (1) -Formula (4), c is the speed of light.

  The position (X, Y, Z) of the GNSS receiver can be obtained from Expression (1) -Expression (4).

  In order to measure the exact position of a mobile unit equipped with a GNSS receiver, it is sufficient to capture at least four GNSS satellites. For example, in the suburbs, there are few objects blocking the radio wave path, so it is easy to capture four or more GNSS satellites with a mobile object. On the other hand, in urban areas, high-rise buildings and other buildings are densely populated, and there are many objects that block radio wave paths, so it is difficult to capture four or more GNSS satellites with a mobile object. In urban areas, even when a GNSS satellite can be captured, not only a direct wave from the GNSS satellite but also a radio wave reflected and diffracted by a building such as a high-rise building may be received. The phenomenon in which radio waves transmitted from GNSS satellites are reflected and diffracted and received from multiple propagation paths is also called multipath. Due to the multipath effect, an error occurs in ranging between the receiving antenna and the GNSS satellite.

  FIG. 2 shows the cause of positioning error in the GNSS receiver. According to FIG. 2, the cause of the positioning error in the GNSS receiver includes multipath, the influence of the ionosphere, and thermal noise. Of these factors, the effect of multipath is the largest. Therefore, multipath countermeasures are indispensable to improve positioning accuracy.

JP 2002-156439 A

  A method for determining whether a signal received by a GNSS receiver is affected by multipath has been proposed. In this proposal, the distance between the GNSS satellite and the GNSS receiver is measured by two correlators. Based on the difference in distance, it is determined whether or not it is affected by multipath. According to this proposal, since it is determined whether two correlators are affected by multipath, it is possible to determine with a small number of correlators.

  It has also been proposed to determine whether or not it is affected by a multipath based on a multipath route difference.

  FIG. 3 shows an example in which it is determined whether or not it is affected by the multipath based on the path difference between the multipaths.

  According to FIG. 3, the multipoint is determined by the difference in the phase of the midpoint of the line segment connecting Early (leading phase) and Late (lagging phase) in the relationship between the phase obtained when the GNSS satellite is acquired and the correlation value. It is determined whether it is affected by the path. For example, the phase of the midpoint of the line segment connecting Early and Late obtained by two correlators is compared. In the two correlators, inverse correlation codes having different phase differences are generated. In this case, when there is no difference in the phase of the midpoint of the line segment that connects Early and Late, it is determined that there is no influence of multipath.

  When it is determined whether or not it is affected by multipath due to the difference in the phase of the midpoint of the line connecting Early and Late, depending on the path difference between the received signal and multipath, Nevertheless, there may be no difference in the phase of the midpoint between Early and Late. In positioning using a GNSS satellite, it is a serious problem to determine that it is not affected despite being affected by multipath. It is problematic to install such a GNSS receiver in a vehicle. This is because the vehicle may be controlled based on the position information measured by the GNSS receiver.

  FIG. 4 is a diagram illustrating the reason why it is determined that there is no difference in the phase of the midpoint of the line segment connecting Early and Late despite being affected by multipath. FIG. 4 shows the relationship between the path difference and the phase difference at the midpoint of the line segment connecting Early and Late obtained by the two correlators (correlator A and correlator B). In FIG. 4, “the phase of the midpoint of the line connecting Early and Late obtained by the correlator A” and “the phase of the midpoint of the line connecting Early and Late obtained by the correlator B” The difference in phase indicates the phase difference (error). According to FIG. 4, it can be seen that the phase difference at the midpoint of the line segment connecting Early and Late periodically increases and decreases. This is because a positioning signal in which distance information is superimposed on a 1.5 GHz carrier wave is transmitted from a GNSS satellite. When the phase difference between the direct wave and the reflected wave becomes a certain value by the positioning signal, the phase difference at the midpoint of the line segment connecting Early and Late is temporarily canceled (“error zero”). . Therefore, if it is determined whether it is affected by multipath at a point where the phase difference between the midpoints of the line connecting Early and Late is zero, it is affected by multipath. Nevertheless, it is determined not to be affected by multipath. In other words, there is no difference in the phase of the midpoint of the line segment connecting Early and Late obtained by the two correlators.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a GNSS receiving apparatus and method that can improve the determination accuracy of whether or not it is affected by multipath.

This GNSS receiver
A GNSS receiver that receives a positioning signal transmitted from a GNSS satellite,
A plurality of correlators for generating an inverse correlation code for the positioning signal and performing a correlation process between the inverse correlation code and the positioning signal;
A control unit based on the moving speed of the GNSS receiver, and controls the correlation processing time in the plurality of correlators,
A determination unit that determines whether a positioning signal from the GNSS satellite is affected by a multipath based on correlation characteristics obtained by the plurality of correlators;
The plurality of correlators generate inverse correlation codes having different phase differences.

This method
A method in a GNSS receiver for receiving a positioning signal transmitted from a GNSS satellite,
A correlation processing step of generating an inverse correlation code for the positioning signal and performing correlation processing between the inverse correlation code and the positioning signal by a plurality of correlators;
A correlation processing time control step for controlling a correlation processing time in the plurality of correlators based on a moving speed of the GNSS receiver;
A determination step of determining whether a positioning signal from the GNSS satellite is affected by a multipath based on a correlation characteristic obtained by the correlation processing step;
In the correlation processing step, the plurality of correlators generate inverse correlation codes having different phase differences.

  According to the disclosed GNSS receiving apparatus and method, it is possible to improve the determination accuracy of whether or not it is affected by multipath.

It is explanatory drawing which shows the positioning method in a GNSS receiver. It is explanatory drawing which shows a positioning error factor. It is explanatory drawing which shows the example of determination of the presence or absence of multipath. It is explanatory drawing which shows one cause which misjudges the presence or absence of multipath. It is a functional block diagram of a GNSS receiver according to an embodiment. It is explanatory drawing which shows the example of a setting of the monitoring time 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. It is explanatory drawing which shows the example of a setting of the monitoring time 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. 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 a direct wave and multipath. It is a functional block diagram which shows the monitoring time control part of the GNSS receiver according to one Example. It is explanatory drawing which shows the example of a setting of the monitoring time in the GNSS receiver according to one Example. It is explanatory drawing which shows the path | route difference which arises by multipath. It is explanatory drawing which shows the relationship between a path | route difference and a pseudo range error. It is explanatory drawing which shows the sky plot of a satellite orbit. It is a flowchart which shows operation | movement of the GNSS receiver according to one Example.

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.

<First embodiment>
<System>
A global navigation satellite system (GNSS) according to this 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, placed on the L1 band carrier (frequency: 1575.42 MHz), and constantly broadcast toward the earth. In addition, the navigation message is spread by the P code, and is always broadcast to the earth on the L2 band carrier (frequency: 1227.6 MHz).

  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 L2 band carrier wave is a Cos wave modulated with a P 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 six orbiting planes inclined by 55 degrees, each with four 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.

<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. In the present embodiment, a case where it is mounted on a vehicle will be described as an example of a moving body.

  The GNSS receiver 100 has at least two correlators. In this embodiment, a case where two correlators are provided will be described as an example. You may make it have two or more correlators. In other words, the GNSS receiver 100 has a plurality of correlators. The two correlators generate inverse correlation codes with different phase differences. The GNSS receiver 100 monitors the phase of the midpoint of the line segment connecting the Early phase (leading phase) and the Late phase (lagging phase) obtained by the two correlators for a predetermined time. Hereinafter, the phase of the midpoint of the line segment connecting Early and Late is referred to as “midpoint phase”. The predetermined time is set according to the speed of the vehicle. For example, a shorter time is set as the vehicle speed increases, and a longer time is set as the vehicle speed decreases. The GNSS receiver 100 obtains the difference between the midpoint phases obtained by the two correlators. By changing the time to monitor the midpoint phase according to the vehicle speed, the fluctuation period of the path difference (phase difference) changes according to the vehicle speed. You can determine whether you are receiving.

  FIG. 5 shows an example of a GNSS receiver according to the present embodiment.

  The GNSS receiver 100 includes a high frequency circuit 102. The high frequency circuit 102 converts radio waves from the GNSS satellite received by the antenna into baseband signals. The baseband signal is input to a correlator A104 and a correlator B106.

  The GNSS receiver 100 includes a correlator A104. Correlator A104 generates an inverse correlation code. The correlator A104 performs correlation processing between the inverse correlation code and the baseband signal input by the high frequency circuit 102 for a predetermined correlation processing time. For example, two inverse correlation codes called Early and Late may be used. Correlator A104 outputs a midpoint phase between Early and Late (midpoint phase) to difference calculation section 110.

  The GNSS receiver 100 includes a correlator B106. Correlator B106 generates an inverse correlation code. The correlator B 106 performs correlation processing between the inverse correlation code and the baseband signal input by the high frequency circuit 102 for a predetermined correlation processing time. For example, two inverse correlation codes called Early and Late may be used. The correlator B106 outputs the phase (midpoint phase) of the midpoint of the line segment connecting Early and Late to the difference calculation unit 110.

  The GNSS receiver 100 has a monitor time control unit 108. Vehicle speed information is input to the monitor time control unit 108. The monitor time control unit 108 controls the processing time in the correlation processing executed by the correlator A104 and the correlator B106. In other words, the timing of correlation processing is controlled. This is because the timing of correlation processing is also controlled by controlling the correlation processing time.

  FIG. 6 shows an example of the monitoring time controlled by the monitoring time control unit 108. In FIG. 6, the horizontal axis is the vehicle speed, and the vertical axis is the monitoring time. For example, the monitor time control unit 108 sets the monitor time (F) to a shorter time as the vehicle speed is faster, and controls the monitor time to be longer as the vehicle speed is slower. The fluctuation cycle of the path difference (phase difference) varies depending on the vehicle speed. The faster the vehicle speed, the shorter the fluctuation cycle of the path difference (phase difference), and the slower the vehicle speed, the longer the fluctuation cycle of the path difference (phase difference). It is.

  The GNSS receiver 100 includes a difference calculation unit 110. The difference calculation unit 110 obtains a difference between the midpoint phase input by the correlator A104 and the midpoint phase input by the correlator B106. The difference calculation unit 110 inputs the difference information to the difference determination unit 112.

  The GNSS receiver 100 includes a difference determination unit 112. The difference determination unit 112 determines whether the radio wave from the GNSS satellite received by the GNSS receiver 100 is affected by the multipath based on the difference information input by the difference calculation unit 110. For example, based on the difference information, the difference determination unit 112 determines that there is a multipath effect when there is the difference. Further, the difference determination unit 112 determines based on the difference information that there is no influence of multipath when there is no difference. The difference determination unit 112 outputs a determination result as to whether or not it is affected by multipath.

<Operation of this GNSS receiver>
FIG. 7 is a flowchart showing the operation of the GNSS receiver 100.

  The GNSS receiver 100 counts up a timer (step S702). For example, the monitor time control unit 108 counts up the timer value (N).

  The GNSS receiver 100 determines whether or not the timer value (N) has reached the monitoring time F controlled based on the vehicle speed (step S704). For example, the monitor time control unit 108 determines whether or not the timer value (N) has reached the monitor time F.

  When it is determined that the timer value (N) has reached the monitoring time F (step S704: YES), the timer value (N) is set to zero (step S706).

  The GNSS receiver 100 obtains the difference between the midpoint phases obtained by the two correlators (step S708). For example, the difference calculation unit 110 obtains a difference between the midpoint phase input from the correlator A104 and the midpoint phase input from the correlator B.

  The GNSS receiver 100 determines whether there is a difference, in other words, whether the difference is zero based on the difference obtained in step S708 (step S710). For example, the difference determination unit 112 determines whether there is a difference based on the difference information input by the difference calculation unit 110.

  If it is determined in step S710 that there is a difference (step S710: YES), the GNSS receiver 100 determines that the radio wave transmitted by the GNSS satellite is affected by multipath (step S712). For example, if the difference determination unit 112 determines that the difference is not zero, it determines that the difference is affected by multipath.

  When it is determined in step S710 that there is no difference (step S710: NO), the GNSS receiver 100 determines that the radio wave transmitted by the GNSS satellite is not affected by the multipath (step S714). For example, if the difference determination unit 112 determines that the difference is zero, it determines that the difference is not affected by multipath.

  When the processes in steps S712 and S714 are completed, if it is not determined in step S704 that the timer value (N) has reached the monitoring time F (step S704: NO), the process returns to step S702.

  According to the present embodiment, since the monitoring time is controlled according to the vehicle speed, it can be determined whether or not it is affected by the multipath in the minimum necessary time. To determine the position of a vehicle equipped with the GNSS receiver, radio waves from at least four GNSS satellites should be used. Therefore, positioning is performed by excluding GNSS satellites that are determined to be affected by multipath. By performing the operation, the positioning accuracy can be improved.

<Modification>
FIG. 8 shows the present GNSS receiver.

  The GNSS receiver 100 includes integrators 114 and 116 in the GNSS receiver described with reference to FIG. Further, the monitor time control unit 108 is connected to the integrators 114 and 116.

  Correlator A104 generates an inverse correlation code. The correlator A 104 performs correlation processing between the inverse correlation code and the baseband signal input by the high frequency circuit 102. For example, two inverse correlation codes called Early and Late may be used. Correlator A104 outputs to integrator 114 the phase (midpoint phase) of the midpoint of the line segment connecting Early and Late.

  The integrator 114 is connected to the correlator 104 and the difference calculation unit 110. The integrator 114 integrates the midpoint phase input by the correlator A104 during a predetermined monitoring time. The integrator 114 outputs the integrated value of the midpoint phase to the difference calculation unit 110.

  Correlator B106 generates an inverse correlation code. The correlator B 106 performs correlation processing between the inverse correlation code and the baseband signal input by the high frequency circuit 102. For example, two inverse correlation codes called Early and Late may be used. Correlator B 106 outputs to integrator 116 the phase (mid point phase) of the midpoint of the line segment connecting Early and Late.

  The integrator 116 is connected to the correlator B106 and the difference calculation unit 110. The integrator 116 integrates the midpoint phase input by the correlator B106 for a predetermined monitoring time. The integrator 116 outputs the integrated value of the midpoint phase to the difference calculation unit 110.

  The monitor time control unit 108 controls the integration time in the integration process executed by the integrator 114 and the integrator 116.

  The accumulated time set by the monitor time control unit 108 is the same as that shown in FIG. For example, the monitor time control unit 108 sets the accumulated time (F) to a shorter time as the vehicle speed is faster, and sets the accumulated time to a longer time as the vehicle speed is slower. The fluctuation period of the path difference (phase difference) varies depending on the vehicle speed. The faster the vehicle speed, the shorter the fluctuation period of the path difference (phase difference), and the slower the vehicle speed, the fluctuation period of the path difference (phase difference). This is because it becomes longer.

  The difference calculation unit 110 obtains a difference between the integrated value of the midpoint phase input by the integrator 114 and the integrated value of the midpoint phase input by the integrator 116. The difference calculation unit 110 inputs the difference information to the difference determination unit 112.

  The operation of the GNSS receiver 100 is the same as the flow shown in FIG.

<Second embodiment>
<System>
A global navigation satellite system (GNSS) according to this embodiment is the same as that of the first embodiment.

<GNSS receiver>
FIG. 9 shows a GNSS receiver 100 according to the present embodiment.

  This GNSS receiver 100 is different from the GNSS receiver described with reference to FIG. 5 and the difference determination unit 112 in that a difference storage unit 118, a difference maximum value extraction unit 120, and a difference maximum value extraction time control unit 122. And have.

  The difference storage unit 118 is connected to the difference calculation unit 110. The difference storage unit 118 stores the difference information input by the difference calculation unit 110.

  The difference maximum value extraction unit 120 is connected to the difference storage unit 118. The maximum difference extraction unit 120 extracts and outputs the maximum difference value from the difference information stored in the difference storage unit 118 for each predetermined extraction time.

  The difference maximum value extraction time control unit 122 is connected to the difference maximum value extraction unit 120. Vehicle speed information is input to the maximum difference value extraction time control unit 122. The difference maximum value extraction time control unit 122 controls the extraction time of the maximum difference value extracted by the difference maximum value extraction unit 120 based on the vehicle speed information.

FIG. 10 shows an example of the extraction time F ₂ controlled by the maximum difference extraction time control unit 122. For example, the difference maximum value extraction time control unit 122 sets the extraction time F ₂ to a shorter time as the vehicle speed is faster, and controls the extraction time F ₂ to be longer as the vehicle speed is slower. The fluctuation cycle of the path difference (phase difference) varies depending on the speed of the vehicle. The faster the vehicle speed, the shorter the fluctuation period of the path difference (phase difference), and the slower the vehicle speed, the less the path difference (phase difference). This is because the fluctuation cycle becomes longer.

<Operation of this GNSS receiver>
FIG. 11 is a flowchart showing the operation of the GNSS receiver 100.
The GNSS receiver 100 counts up a timer (step S1102). For example, the monitor time control unit 108 counts up the timer value (N ₁ ).

The GNSS receiver 100 determines whether or not the timer value (N ₁ ) has reached the monitoring time F ₁ controlled based on the vehicle speed (step S1104). For example, the monitor time control unit 108 determines whether or not the timer value (N ₁ ) has reached the monitor time F ₁ .

When it is determined that the timer value (N ₁ ) has reached the monitoring time F ₁ (step S1104: YES), the timer value (N ₁ ) is set to zero (step S1106).

  The GNSS receiver 100 obtains the difference between the midpoint phases obtained by the two correlators (step S1108). For example, the difference calculation unit 110 obtains a difference between the midpoint phase input from the correlator A104 and the midpoint phase input from the correlator B.

  The GNSS receiver 100 stores the difference obtained in step S1108 (step S1110). For example, the difference storage unit 118 stores the difference information input by the difference calculation unit 110.

The GNSS receiver 100 counts up a timer (step S1112). For example, the difference maximum value extraction time control unit 122 counts up the timer value (N ₂ ).

The GNSS receiver 100 determines whether or not the timer value (N ₂ ) has reached the extraction time F ₂ that is controlled based on the vehicle speed (step S1114). For example, the maximum difference value extraction time control unit 122 determines whether the timer value (N ₂ ) has reached the extraction time F ₂ .

When it is determined that the timer value (N ₂ ) has reached the extraction time F ₂ (step S1114: YES), the timer value (N ₂ ) is set to zero (step S1116).

  The GNSS receiver 100 extracts the maximum difference value (step S1118). For example, the maximum difference value extraction unit 120 extracts and outputs the maximum difference value from the difference information stored in the difference storage unit 118.

  The maximum value of the difference output in step S1118 is used as a quantitative multipath influence index.

  According to the present embodiment, by controlling the extraction time of the maximum difference value based on the vehicle speed information, the maximum difference value can be obtained quantitatively in the minimum necessary time. To determine the position of a vehicle equipped with the GNSS receiver, radio waves from at least four GNSS satellites should be used. Therefore, positioning is performed by excluding GNSS satellites that are determined to be affected by multipath. By performing the operation, the positioning accuracy can be improved. In addition, when excluding GNSS satellites determined to be affected by multipath, there may be three or fewer GNSS satellites that can be used for positioning. Even when the number of GNSS satellites that can be used for positioning is three or less, it is possible to compare the maximum value of the difference obtained quantitatively and add the GNSS satellite with the least multipath influence. Even if the number of GNSS satellites that can be used for positioning is less than 3 as a result of adding the positioning of the GNSS satellites that have the least multipath influence, the GNSS satellites that are determined to be affected by the multipath are excluded. The positioning accuracy can be improved as compared with the case where positioning is performed by three or less GNSS satellites.

<Modification>
FIG. 12 shows the present GNSS receiver.

  The GNSS receiver 100 includes integrators 114 and 116 in the GNSS receiver described with reference to FIG. Further, the monitor time control unit 108 is connected to the integrators 114 and 116.

  Correlator A104 generates an inverse correlation code. The correlator A 104 performs correlation processing between the inverse correlation code and the baseband signal input by the high frequency circuit 102. For example, two inverse correlation codes called Early and Late may be used. Correlator A104 outputs to integrator 114 the phase (midpoint phase) of the midpoint of the line segment connecting Early and Late.

  The integrator 114 is connected to the correlator A104 and the difference calculation unit 110. The integrator 114 integrates the midpoint phase input by the correlator A104 during a predetermined monitoring time. The integrator 114 outputs the integrated value of the midpoint phase to the difference calculation unit 110.

  Correlator B106 generates an inverse correlation code. The correlator B 106 performs correlation processing between the inverse correlation code and the baseband signal input by the high frequency circuit 102. For example, two inverse correlation codes called Early and Late may be used. Correlator B 106 outputs to integrator 116 the phase (mid point phase) of the midpoint of the line segment connecting Early and Late.

  The integrator 116 is connected to the correlator B106 and the difference calculation unit 110. The integrator 116 integrates the midpoint phase input by the correlator B106 for a predetermined monitoring time. The integrator 116 outputs the integrated value of the midpoint phase to the difference calculation unit 110.

  The monitor time control unit 108 controls the integration time in the integration process executed by the integrator 114 and the integrator 116.

  The accumulated time set by the monitor time control unit 108 is the same as that shown in FIG. For example, the monitor time control unit 108 sets the accumulated time (F) to a shorter time as the vehicle speed is faster, and sets the accumulated time to a longer time as the vehicle speed is slower. The fluctuation cycle of the path difference (phase difference) varies depending on the speed of the vehicle. The faster the vehicle speed, the shorter the fluctuation period of the path difference (phase difference), and the slower the vehicle speed, the less the path difference (phase difference). This is because the fluctuation cycle becomes longer.

  The difference calculation unit 110 obtains a difference between the integrated value of the midpoint phase input by the integrator 114 and the integrated value of the midpoint phase input by the integrator 116. The difference calculation unit 110 inputs the difference information to the difference determination unit 112.

  The operation of the GNSS receiver 100 is the same as the flow shown in FIG.

<Third embodiment>
<System>
A global navigation satellite system (GNSS) according to this embodiment is the same as that of the first embodiment.

<GNSS receiver>
FIG. 13 shows a GNSS receiver 100 according to the present embodiment.

  The GNSS receiver 100 is different from the GNSS receiver described with reference to FIG. 9 in that a difference determination unit 112 is included.

  The difference determination unit 112 is connected to the difference calculation unit 110 and the difference storage unit 118. The difference determination unit 112 determines whether the radio wave from the GNSS satellite received by the GNSS receiver 100 is affected by the multipath based on the difference information input by the difference calculation unit 110. For example, based on the difference information, the difference determination unit 112 determines that there is a multipath effect when there is the difference. Further, the difference determination unit 112 determines based on the difference information that there is no influence of multipath when there is no difference. The difference determination unit 112 outputs the difference information input by the difference calculation unit 110 and the determination result as to whether or not it is affected by multipath.

  The difference storage unit 118 is connected to the difference determination unit 112. The difference storage unit 118 stores the difference information input by the difference determination unit 112.

<Operation of this GNSS receiver>
FIG. 14 is a flowchart showing the operation of the GNSS receiver 100.
The GNSS receiver 100 counts up a timer (step S1402). For example, the monitor time control unit 108 counts up the timer value (N ₁ ).

The GNSS receiver 100 determines whether or not the timer value (N ₁ ) has reached the monitoring time F ₁ controlled based on the vehicle speed (step S1404). For example, the monitor time control unit 108 determines whether or not the timer value (N ₁ ) has reached the monitor time F ₁ .

When it is determined that the timer value (N ₁ ) has reached the monitoring time F ₁ (step S1404: YES), the timer value (N ₁ ) is set to zero (step S1406). If it is not determined that the timer value (N ₁ ) has reached the monitoring time F ₁ (step S1404: NO), the process returns to step S1402.

  The GNSS receiver 100 obtains the difference between the midpoint phases obtained by the two correlators (step S1408). For example, the difference calculation unit 110 obtains a difference between the midpoint phase input by the correlator A104 and the midpoint phase input by the correlator B106.

  The GNSS receiving apparatus 100 stores the difference obtained in step S1408 (step S1410). For example, the difference storage unit 118 stores the difference information input by the difference determination unit 112.

  The GNSS receiver 100 determines whether there is a difference, in other words, whether the difference is zero based on the difference obtained in step S1408 (step S1412). For example, the difference determination unit 112 determines whether there is a difference based on the difference information input by the difference calculation unit 110.

  When it is determined in step S1412 that there is a difference (step S1412: YES), the GNSS receiver 100 determines that the radio wave transmitted by the GNSS satellite is affected by multipath (step S1414). For example, if the difference determination unit 112 determines that the difference is not zero, it determines that the difference is affected by multipath.

  If it is determined in step S1412 that there is no difference (step S1412: NO), the GNSS receiver 100 determines that the radio wave transmitted by the GNSS satellite is not affected by the multipath (step S1416). For example, if the difference determination unit 112 determines that the difference is zero, it determines that the difference is not affected by multipath. If it is determined that there is no influence of multipath, the process returns to step S1402.

When it is determined in step S1414 that the multipath is affected, the GNSS receiver 100 counts up a timer (step S1418). For example, the difference maximum value extraction time control unit 122 counts up the timer value (N ₂ ).

The GNSS receiver 100 determines whether or not the timer value (N ₂ ) has reached the extraction time F ₂ that is controlled based on the vehicle speed (step S1420). For example, the maximum difference value extraction time control unit 122 determines whether the timer value (N ₂ ) has reached the extraction time F ₂ .

When it is determined that the timer value (N ₂ ) has reached the extraction time F ₂ (step S1420: YES), the timer value (N ₂ ) is set to zero (step S1422). When it is not determined that the timer value (N ₂ ) has reached the extraction time F ₂ (step S1422: NO), the process returns to step S1402.

  The GNSS receiver 100 extracts the maximum difference (step S1424). For example, the maximum difference value extraction unit 120 extracts and outputs the maximum difference value from the difference information stored in the difference storage unit 118.

  The maximum value of the difference output in step S1424 is used as a quantitative multipath influence index.

  According to the present embodiment, by controlling the extraction time of the maximum difference value based on the vehicle speed information, the maximum difference value can be obtained quantitatively in the minimum necessary time. In addition, since the monitoring time is controlled according to the vehicle speed, it can be determined whether or not it is affected by multipath in the minimum necessary time.

  To determine the position of a vehicle equipped with the GNSS receiver, radio waves from at least four GNSS satellites should be used. Therefore, positioning is performed by excluding GNSS satellites that are determined to be affected by multipath. By performing the operation, the positioning accuracy can be improved. In addition, when excluding GNSS satellites determined to be affected by multipath, there may be three or fewer GNSS satellites that can be used for positioning. Even when the number of GNSS satellites that can be used for positioning is three or less, it is possible to compare the maximum value of the difference obtained quantitatively and add the GNSS satellite with the least multipath influence. Even if the number of GNSS satellites that can be used for positioning is less than 3 as a result of adding the positioning of the GNSS satellites that have the least multipath influence, the GNSS satellites that are determined to be affected by the multipath are excluded. The positioning accuracy can be improved as compared with the case where positioning is performed by three or less GNSS satellites.

<Modification>
FIG. 15 shows the present GNSS receiver.

  The GNSS receiver 100 includes integrators 114 and 116 in the GNSS receiver described with reference to FIG. Further, the monitor time control unit 108 is connected to the integrators 114 and 116.

  Correlator A104 generates an inverse correlation code. The correlator A 104 performs correlation processing between the inverse correlation code and the baseband signal input by the high frequency circuit 102. For example, two inverse correlation codes called Early and Late may be used. Correlator A104 outputs to integrator 114 the phase (midpoint phase) of the midpoint of the line segment connecting Early and Late.

  The integrator 114 is connected to the correlator 104 and the difference calculation unit 110. The integrator 114 integrates the midpoint phase input by the correlator A104 during a predetermined monitoring time. The integrator 114 outputs the integrated value of the midpoint phase to the difference calculation unit 110.

  Correlator B106 generates an inverse correlation code. The correlator B 106 performs correlation processing between the inverse correlation code and the baseband signal input by the high frequency circuit 102. For example, two inverse correlation codes called Early and Late may be used. Correlator B 106 outputs to integrator 116 the phase (mid point phase) of the midpoint of the line segment connecting Early and Late.

  The integrator 116 is connected to the correlator B106 and the difference calculation unit 110. The integrator 116 integrates the midpoint phase input by the correlator B106 for a predetermined monitoring time. The integrator 116 outputs the integrated value of the midpoint phase to the difference calculation unit 110.

  The monitor time control unit 108 controls the integration time in the integration process executed by the integrator 114 and the integrator 116.

  The accumulated time set by the monitor time control unit 108 is the same as that shown in FIG. For example, the monitor time control unit 108 sets the accumulated time (F) to a shorter time as the vehicle speed is faster, and sets the accumulated time to a longer time as the vehicle speed is slower. The fluctuation cycle of the path difference (phase difference) varies depending on the speed of the vehicle. The faster the vehicle speed, the shorter the fluctuation period of the path difference (phase difference), and the slower the vehicle speed, the less the path difference (phase difference). This is because the fluctuation cycle becomes longer.

  The difference calculation unit 110 obtains a difference between the integrated value of the midpoint phase input by the integrator 114 and the integrated value of the midpoint phase input by the integrator 116. The difference calculation unit 110 inputs the difference information to the difference determination unit 112.

  The operation of this GNSS receiver 100 is the same as the flow shown in FIG.

<Fourth embodiment>
<System>
A global navigation satellite system (GNSS) according to this embodiment is the same as that of the first embodiment.

<GNSS receiver>
The GNSS receiver 100 will be described with reference to a functional block diagram shown in FIG.

  FIG. 16 shows multipath (reflected wave).

  The route when the radio wave from the GNSS satellite is affected by the multipath includes the route from the GNSS satellite to the reflector and the route from the reflector to the GNSS receiver. Reflectors include buildings.

  Of the paths included in the multipath wave, the path from the GNSS satellite to the reflector is longer than the path from the reflector to the GNSS receiver. Therefore, it is assumed that the path of the multipath wave is mainly affected by the path from the reflector to the GNSS receiver. The path from the reflector to the GNSS receiver is affected by the movement of the vehicle on which the GNSS receiver is mounted.

  However, when the vehicle is stopped or traveling at an extremely low speed, it is assumed that the influence of the movement of the GNSS satellite cannot be ignored.

  Therefore, the GNSS receiver 100 has a phase of the midpoint of the line segment connecting Early and Late obtained by the two correlators for a predetermined time set in accordance with the speed of the vehicle and the orbit of the GNSS satellite. Is monitored for a predetermined time.

  The GNSS receiver 100 differs in the function of the monitor time control unit 108 in the functional block diagram shown in FIG.

  FIG. 17 shows the monitoring time control unit 108 of the GNSS receiver 100.

  The monitoring time control unit 108 included in the GNSS receiver 100 includes a vehicle speed determination unit 1082 and a monitoring time setting unit 1084.

  The vehicle speed determination unit 1082 determines whether the vehicle speed is equal to or lower than a predetermined speed K. The speed K is preferably a speed at which it is determined that the influence of the satellite orbit cannot be ignored. For example, the speed K is set based on the satellite orbit and the positional relationship between the vehicle and the reflector. The vehicle speed determination unit 1082 inputs the vehicle speed and information indicating whether the speed is equal to or lower than the speed K to the monitor time setting unit 1084.

  Monitor time setting unit 1084 is connected to vehicle speed determination unit 1084. The vehicle speed determination unit 1084 sets the monitoring time based on the vehicle speed information input by the vehicle speed determination unit 1082 and information indicating whether the vehicle speed is equal to or lower than the speed K.

  FIG. 18 shows an example of setting the monitoring time. In FIG. 18, (1) shows an example of setting the monitoring time according to the first to third embodiments described above. (2) and (3) show setting examples of monitoring time according to the present embodiment.

  According to FIG. 18 (1), when the monitoring time is set based on the vehicle speed, a very long observation time is required at a low speed. Therefore, in the present GNSS receiver 100, when the vehicle is stopped or traveling at a low speed, the orbit of the GNSS satellite has a greater influence on the monitoring time than the vehicle speed. The monitoring time is constant. For example, in FIGS. 18 (2) and 18 (3), when the speed is equal to or lower than K, it is assumed that the influence of the satellite orbit is large, so the monitoring time is constant. The difference between FIG. 18 (2) and (3) indicates the degree of influence of the satellite orbit. Compared with the case of (3), the case of (2) has a greater influence on the satellite orbit. 18 (2) and 18 (3), it is assumed that the region (A) is easily affected by the orbit of the GNSS satellite, and the region (B) is not easily influenced by the orbit of the GNSS satellite.

<Effects of GNSS satellite orbit>
FIG. 19 shows path differences caused by multipath.

  The fluctuation range of the pseudo range (pseudo distance) will be described. The pseudorange varies depending on the phase difference between the direct wave and the reflected wave. Every time the path difference changes by one cycle of the carrier wave, that is, 20 cm, the pseudorange error fluctuates by one cycle. Therefore, the fluctuation period of the pseudo range error can be determined by obtaining the change speed of the path difference.

  In FIG. 19, the receiving antenna is located at the point X. The distance between the point X and the reflecting wall is R, and the elevation angle of the GNSS satellite is θ. Then, the path difference is indicated by the length of A + B.

  Here, cos θ = R / B and cos 2θ = A / B.

Therefore, A + B = (R / cos2θ) (1 + cos2θ) = (R / cos2θ) (1+ (1-2sin ² θ)) = 2Rcosθ (A)
The path difference is indicated by 2Rcosθ.

<Error fluctuation period when the vehicle is stopped>
First, an error fluctuation period when the vehicle is stopped is obtained.

  When the vehicle is stopped, R does not change because the position of the vehicle does not change. When the vehicle is stopped, the elevation angle θ of the satellite changes due to the movement of the GNSS satellite. According to Expression (A), the influence of the path difference becomes larger as the satellite has a higher elevation angle. However, in order to generate a multipath by a high elevation satellite, a high reflecting wall is required. Therefore, in practice, there are not many multipaths from high elevation satellites.

  FIG. 20 shows the relationship between the path difference and the pseudorange error.

  As can be seen from FIG. 20, the maximum error occurs when the error amount due to the narrow correlator is 0.17 chip.

  Assume that the elevation angle of the satellite that actually generates multipath is 30 °. The distance R between the reflecting wall and the vehicle is set to 50 m (= 0.17 chip) at which the error amount by the narrow correlator is maximized. If the amount of change in elevation required to change the path difference by 20 cm is Δθ, Δθ can be obtained from equation (A).

0.2 = 2Rcos30 ° -2Rcos (30 ° + Δθ)
Δθ = 0.066 °
FIG. 21 shows a sky plot of the satellite orbit.

  The amount of change in the satellite elevation angle per unit time varies depending on the satellite orbit. It becomes the maximum when moving vertically around the target elevation angle (30 °) as indicated by point A in FIG. When the amount of change in the satellite elevation angle is the maximum, it is about 30 ° per hour. Moreover, it becomes the minimum when moving around the target elevation angle horizontally like point B. When the amount of change in the satellite elevation angle is minimal, it is about 3 ° per hour.

From the above, the time t ₁ required for the elevation angle to change by 0.066 ° is t ₁ = 8 sec-80 sec. It said time t ₁ is the fluctuation cycle of the pseudo range error when parked. For example, when traveling in an urban area, the fluctuation period when a pseudo range error of a certain satellite stops is about 30 seconds.

<Error fluctuation period when the vehicle is moving>
Next, an error fluctuation period when the vehicle is moving is obtained.

  When the vehicle is moving, R changes because the position of the vehicle changes. When the vehicle is moving, the elevation angle θ of the satellite also changes due to the movement of the GNSS satellite.

Assume that the elevation angle of the satellite that actually generates multipath is 30 °. The moving speed of the vehicle with respect to the reflecting wall is 60 km / h. In the formula (A), if the amount of change in R per unit time is ΔR, ΔR = 17 m / s. Accordingly, the time t ₂ required for the path difference to change by 20 cm is t ₂ = 6 msec. Time t ₂ becomes longer as the vehicle speed decreases.

  From the above, the fluctuation range t of the pseudo range error is t = 6 msec-80 sec when the vehicle is stopped—60 km / h.

  Therefore, when the vehicle speed is equal to or lower than the speed K, the monitoring time is preferably set to a value of about 80 seconds. Also. The speed K is preferably set to a speed at which the monitoring time is 80 seconds.

<Operation of this GNSS receiver>
FIG. 22 is a flowchart showing the operation of the GNSS receiver 100.

  The GNSS receiver 100 determines whether the speed of the vehicle on which the GNSS receiver 100 is mounted exceeds the speed K (step S2202). For example, the speed determination unit 1082 determines whether the vehicle speed information exceeds a preset speed K.

  When it is determined that the vehicle speed exceeds the speed K (step S2202: YES), the GNSS receiver 100 counts up a timer (step S2204). For example, the monitor time control unit 108 counts up the timer value (N).

  The GNSS receiver 100 determines whether or not the timer value (N) has reached the monitoring time F controlled based on the vehicle speed (step S2206). For example, the monitor time control unit 108 determines whether or not the timer value (N) has reached the monitor time F.

  When it is determined that the timer value (N) has reached the monitoring time F (step S2206: YES), the timer value (N) is set to zero (step S2208).

  The GNSS receiver 100 obtains the difference between the midpoint phases obtained by the two correlators (step S2210). For example, the difference calculation unit 110 obtains a difference between the midpoint phase input from the correlator A104 and the midpoint phase input from the correlator B.

  The GNSS receiver 100 determines whether there is a difference, in other words, whether the difference is zero based on the difference obtained in step S2210 (step S2212). For example, the difference determination unit 112 determines whether there is a difference based on the difference information input by the difference calculation unit 110.

  If it is determined in step S2212 that there is a difference (step S2212: YES), the GNSS receiver 100 determines that the radio wave transmitted by the GNSS satellite is affected by multipath (step S2214). For example, if the difference determination unit 112 determines that the difference is not zero, it determines that the difference is affected by multipath.

  If it is determined in step S2212 that there is no difference (step S2212: NO), the GNSS receiver 100 determines that the radio wave transmitted by the GNSS satellite is not affected by the multipath (step S2216). For example, if the difference determination unit 112 determines that the difference is zero, it determines that the difference is not affected by multipath.

  When it is not determined that the vehicle speed exceeds the speed K (step S2202: NO), the GNSS receiver 100 counts up a timer (step S2218). For example, the monitor time control unit 108 counts up the timer value (M).

  The GNSS receiver 100 determines whether or not the timer value (M) has reached the monitoring time F controlled based on the vehicle speed and the satellite orbit (step S2220). For example, the monitor time control unit 108 determines whether or not the timer value (M) has reached the monitor time F.

  When it is determined that the timer value (M) has reached the monitoring time F (step S2220: YES), the timer value (M) is set to zero (step S2222).

  The GNSS receiver 100 obtains the difference between the midpoint phases obtained by the two correlators (step S2224). For example, the difference calculation unit 110 obtains a difference between the midpoint phase input from the correlator A104 and the midpoint phase input from the correlator B.

  The GNSS receiver 100 determines whether there is a difference, in other words, whether the difference is zero based on the difference obtained in step S2224 (step S2226). For example, the difference determination unit 112 determines whether there is a difference based on the difference information input by the difference calculation unit 110.

  When it is determined in step S2226 that there is a difference (step S2226: YES), the GNSS receiver 100 determines that the radio wave transmitted by the GNSS satellite is affected by multipath (step S2228). For example, if the difference determination unit 112 determines that the difference is not zero, it determines that the difference is affected by multipath.

  When it is determined in step S2212 that there is no difference (step S2226: NO), the GNSS receiver 100 determines that the radio wave transmitted by the GNSS satellite is not affected by the multipath (step S2230). For example, if the difference determination unit 112 determines that the difference is zero, it determines that the difference is not affected by multipath.

  When the processes of steps S2214, S2216, S2228, and S2230 are completed, the process returns to step S2202.

  According to the present embodiment, since the monitoring time is controlled according to the vehicle speed and the satellite orbit, it can be determined whether or not it is affected by the multipath in the minimum necessary time. This is because the monitoring time does not become longer than necessary even when the vehicle is stopped or moving at a low speed. To determine the position of a vehicle equipped with the GNSS receiver, radio waves from at least four GNSS satellites should be used. Therefore, positioning is performed by excluding GNSS satellites that are determined to be affected by multipath. By performing the operation, the positioning accuracy can be improved.

<Modification>
This GNSS receiver is explained by the GNSS receiver shown in FIG.

  The GNSS receiver 100 includes integrators 114 and 116 in the GNSS receiver described with reference to FIG. Further, the monitor time control unit 108 is connected to the integrators 114 and 116.

  Correlator A104 generates an inverse correlation code. The correlator A 104 performs correlation processing between the inverse correlation code and the baseband signal input by the high frequency circuit 102. For example, two inverse correlation codes called Early and Late may be used. Correlator A104 outputs to integrator 114 the phase (midpoint phase) of the midpoint of the line segment connecting Early and Late.

  The integrator 114 is connected to the correlator 104 and the difference calculation unit 110. The integrator 114 integrates the midpoint phase input by the correlator A104 during a predetermined monitoring time. The integrator 114 outputs the integrated value of the midpoint phase to the difference calculation unit 110.

  Correlator B106 generates an inverse correlation code. The correlator B 106 performs correlation processing between the inverse correlation code and the baseband signal input by the high frequency circuit 102. For example, two inverse correlation codes called Early and Late may be used. Correlator B 106 outputs to integrator 116 the phase (mid point phase) of the midpoint of the line segment connecting Early and Late.

  The integrator 116 is connected to the correlator B106 and the difference calculation unit 110. The integrator 116 integrates the midpoint phase input by the correlator B106 for a predetermined monitoring time. The integrator 116 outputs the integrated value of the midpoint phase to the difference calculation unit 110.

  The monitor time control unit 108 controls the integration time in the integration process executed by the integrator 114 and the integrator 116.

  The accumulated time set by the monitor time control unit 108 is the same as that shown in FIGS. 18 (2) and 18 (3). For example, the monitor time control unit 108 sets the accumulated time (F) to a shorter time as the vehicle speed is faster, and sets the accumulated time to a longer time as the vehicle speed is slower. However, when the vehicle speed is slower than the speed K, it is controlled to a constant value.

  The difference calculation unit 110 obtains a difference between the integrated value of the midpoint phase input by the integrator 114 and the integrated value of the midpoint phase input by the integrator 116. The difference calculation unit 110 inputs the difference information to the difference determination unit 112.

  The operation of this GNSS receiver 100 is the same as the flow shown in FIG.

  Note that the monitoring time control unit according to the present embodiment may be applied to the second and third embodiments described above. By applying the monitoring time control unit according to the present embodiment, it is possible to determine the presence / absence of multipath in the minimum necessary time, and to obtain the maximum difference value.

  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.

100 GNSS Receiver 102 High Frequency Circuit 104 Correlator A
106 Correlator B
108 monitor time control unit 1082 vehicle speed determination unit 1084 monitor time setting unit 110 difference calculation unit 112 difference determination unit 114 integrator 116 integrator 118 difference storage unit 120 difference maximum value extraction unit 122 difference maximum value extraction time control unit

Claims (6)

A GNSS receiver that receives a positioning signal transmitted from a GNSS satellite,
A plurality of correlators for generating an inverse correlation code for the positioning signal and performing a correlation process between the inverse correlation code and the positioning signal;
A control unit based on the moving speed of the GNSS receiver, and controls the correlation processing time in the plurality of correlators,
A determination unit that determines whether a positioning signal from the GNSS satellite is affected by a multipath based on correlation characteristics obtained by the plurality of correlators;
The plurality of correlators are GNSS receivers that generate inverse correlation codes having different phase differences. In the GNSS receiver according to claim 1,
The control unit is a GNSS receiver that sets a correlation processing time in the plurality of correlators to a shorter time as the moving speed is higher. In the GNSS receiver according to claim 1 or 2,
A difference calculation unit for calculating a phase difference between midpoints of the leading phase and the lagging phase obtained by the plurality of correlators;
The determination unit is a GNSS reception apparatus that determines that a multipath is affected when there is a difference based on the difference information obtained by the difference calculation unit. In the GNSS receiver according to claim 3,
A difference storage unit that stores difference information obtained by the difference calculation unit;
From the difference information stored in the difference storage unit, a difference maximum value extraction unit that acquires a maximum value of the difference every predetermined time;
Wherein based on the moving velocity of the GNSS receiver, GNSS receiver including an extraction time control unit for controlling the time of extraction in the maximum difference extraction section. In the GNSS receiver according to any one of claims 1 to 4,
A moving speed determination unit for determining whether the moving speed of the GNSS receiver is less than a predetermined speed;
Wherein, when the moving speed of the GNSS receiver by the moving speed determining unit is determined to be less than the predetermined speed, based on the trajectory of the moving speed and the GNSS satellites, of the plurality of correlators A GNSS receiver that controls the correlation processing time. A method in a GNSS receiver for receiving a positioning signal transmitted from a GNSS satellite,
A correlation processing step of generating an inverse correlation code for the positioning signal and performing correlation processing between the inverse correlation code and the positioning signal by a plurality of correlators;
Based on the moving speed of the GNSS receiver, a correlation processing time control step of controlling the correlation process time in the plurality of correlators,
A determination step of determining whether a positioning signal from the GNSS satellite is affected by a multipath based on a correlation characteristic obtained by the correlation processing step;
In the correlation processing step, the plurality of correlators generate inverse correlation codes having different phase differences.

Images