JP2010249620A - Positioning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform accurate positioning by appropriately removing a poor influence to satellite signals, such as a multipath, according to situations. <P>SOLUTION: In analog sections 3A, 3B, 3C, width of a band to be narrowed down in filtering for cutting unnecessary noise components outside the band included in satellite signals is set such that the width gradually increases in the order of an analog section 3A, an analog section 3B, and an analog section 3C. Then, each digital signal processing section 4 selects one of the analog sections 3A, 3B, 3C, and uses satellite signals processed by the selected analog section. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a positioning device.

  As a positioning device that is mounted on a moving body such as an automobile and measures the current position, a device that uses GPS is known. This is a technique for measuring the current position of a moving body based on signals from a plurality of GPS (Global Positioning System) satellites received by an antenna installed in the moving body.

  In such a positioning apparatus, an analog unit that performs analog signal processing performs a filtering process to cut off a noise component outside the extra band included in the satellite signal. In other words, when satellite signals are captured by a digital signal processing unit that performs digital signal processing after the analog unit, it is better to narrow down the band by this filtering process because the noise components and interference waves are sufficiently cut off. It is preferable because the signal is easily captured. On the other hand, when tracking the satellite signal, if the band is narrowed too much, the vicinity of the peak of the correlation between the PN code and the satellite signal will be distorted, so that the tracking of the peak point will be shifted and the tracking accuracy will deteriorate. There is a conflicting problem.

  In the positioning device, the tracking point may fluctuate carelessly due to the influence of multipath (a reflected wave of a satellite signal reflected by a building or the like) particularly in an urban area. Therefore, the tracking control is generally performed by applying a low-pass filter to the control value for the correlation value so as not to track the fluctuation due to the multipath of the tracking point. As a result, it is possible to average the fluctuations of the multipaths so that the tracking point does not track even though the tracking points change due to the multipaths. On the other hand, the moving amount of the moving body that performs positioning is large. Therefore, when the tracking point actually moves greatly, if the low pass filter is strongly applied, the response characteristic will deteriorate and tracking will be delayed. There is.

  Furthermore, in the positioning device, the positioning calculation unit that performs the positioning calculation calculates the speed and position of the moving body provided with the antenna from the pseudorange and Doppler frequency measured in each channel corresponding to each satellite. Because the influence of the path is larger at the positioning position than the positioning speed, filtering by a filter that smoothes the positioning position by the positioning speed that normally suppresses the fluctuation of the positioning position to the positioning speed and reduces the influence of multipath is performed. Do. On the other hand, sometimes the positioning speed becomes an error due to the influence of multipath, and there is a conflicting problem that an erroneous positioning position may be obtained instead due to filtering or strong filtering. In this case, the change in the influence of the multipath is severe, and it is difficult to adjust the speed filter to the optimum strength according to the situation.

  It is an object of the present invention to enable accurate positioning by appropriately removing adverse effects on satellite signals such as multipath according to the situation.

  (1) In the present invention, an antenna, a plurality of processing means for performing a process of cutting out a noise component out of the band for each satellite signal received by the antenna, and a selection for selecting one of the plurality of processing means Means, capturing / tracking means for capturing and tracking the satellite signal processed by the processing means selected by the selecting means, and positioning means for performing positioning based on the captured and tracked satellite signal. The plurality of processing means have different bandwidths, and the selection means selects one of the plurality of processing means in accordance with processing performed by the acquisition / tracking means. Device.

  (2) Another aspect of the present invention is an antenna, a plurality of capturing / tracking means for capturing and tracking the satellite signal for each satellite signal received by the antenna, and one of the plurality of capturing / tracking means. And a positioning means for performing positioning based on the satellite signals acquired and tracked by the acquisition / tracking means selected by the selection means, and the plurality of acquisition / tracking means are mutually connected. This is a positioning device with different degrees of multipath suppression.

  (3) In this case, the selection unit is configured to select the plurality of acquisitions based on a comparison between a predetermined threshold value for each acquisition / tracking unit and a signal strength of the satellite signal obtained by the acquisition / tracking unit. -You may make it select one from the tracking means.

  (4) Alternatively, the selection means selects one of the plurality of acquisition / tracking means based on the difference between the pseudorange change in each of the acquisition / tracking means and the Doppler frequency. Also good.

  (5) Alternatively, the selection unit obtains a pseudorange from the speed of the antenna, and based on a comparison between the pseudorange and the pseudorange obtained by each of the capture / tracking units, the plurality of capture / tracking units One of the means may be selected.

  (6) Another aspect of the present invention relates to a plurality of capturing / tracking means for capturing and tracking a satellite signal received by the antenna, and the antenna based on the satellite signal captured and tracked by the capturing / tracking means. A plurality of positioning means for positioning the position and speed, a selection means for selecting one of the plurality of positioning means, and the position and speed measured by the positioning means selected by the selection means Navigation means for performing navigation, wherein the plurality of positioning means have different degrees of filtering, and the selection means is one of the plurality of positioning means according to processing performed by the navigation means. It is a positioning device that selects.

  (7) In this case, the plurality of positioning units may be different in the degree of filtering performed on the speed at which positioning is performed.

  According to the present invention, it is possible to appropriately remove an adverse effect on a satellite signal such as a multipath according to a situation so that accurate positioning can be performed.

It is a block diagram of the electrical connection of the positioning apparatus concerning Embodiment 1 of this invention. It is a block diagram of the electrical connection of the positioning apparatus concerning Embodiment 2 of this invention. It is a block diagram of the electrical connection of the positioning apparatus concerning Embodiment 2 of this invention. It is a block diagram of the electrical connection of the positioning apparatus concerning Embodiment 2 of this invention. It is a block diagram of the electrical connection of the positioning apparatus concerning Embodiment 3 of this invention.

  Embodiments of the present invention will be described below.

[Embodiment 1]
FIG. 1 is a block diagram of electrical connection of the positioning device 1 according to the first embodiment.

  The positioning device 1 includes, for example, an antenna 2 that receives a satellite signal transmitted from a satellite such as a GPS satellite, three analog units 3A, 3B, and 3C that perform analog processing of the received signals of the antenna 2, and an analog unit 3A. , 3B, 3C, a plurality of digital signal processing units 4 that perform digital processing on the satellite signals processed, and positioning that measures the current position of the antenna 2 based on the output result of each digital signal processing unit 4 A calculation unit 5 and a navigation unit 7 that displays the current position of the antenna 2 obtained by the positioning calculation unit 5 using the road map data on the map by the display 6 are provided.

  The analog units 3A, 3B, and 3C perform the following processing, respectively. That is, for example, since a satellite signal of a GPS satellite has a frequency of 1.5 GHz, processing is performed to reduce the frequency to 3.9 MHz so that the positioning device 1 can easily process the signal. Also, a filtering process is performed to cut out a noise component outside the extra band included in the satellite signal.

  The plurality of digital signal processing units 4 are digital signal processing units of channel 0 (ch0), channel 1 (ch1),..., Channel X (chX), respectively, and each channel corresponds to each satellite. Each digital signal processing unit 4 captures (searches) a satellite signal and tracks (tracks) the captured satellite signal. That is, the digital signal processing unit 4 generates a plurality of PN codes whose phases are gradually shifted, and captures satellite signals by correlating the PN codes with the satellite signals. Then, the captured satellite signal is tracked.

  Here, in the analog units 3A, 3B, and 3C, as described above, filtering processing is performed to cut out noise components outside the extra band included in the satellite signal. When the satellite signal is captured by the digital signal processing unit 4, it can be said that it is preferable to narrow the band by this filtering process because a good noise component and an interference wave are sufficiently cut and the satellite signal is easily captured. On the other hand, when tracking a satellite signal, if the band is narrowed too much, the vicinity of the peak of the correlation between the PN code and the satellite signal will be distorted, so that tracking of the peak point will be shifted and tracking accuracy will deteriorate. End up. Therefore, when capturing satellite signals, it is desirable to narrow the band by filtering processing, and when tracking satellite signals, it is better to widen the width of the narrowing band in filtering processing than in this case. Further, when it is desired to improve the tracking accuracy of the satellite signal, it is desirable to further widen the band width to be narrowed in the filtering process.

  Therefore, in the analog units 3A, 3B, and 3C, the band widths to be narrowed down when performing filtering processing to cut out noise components outside the extra band included in the satellite signal are the analog units 3A, 3B, and 3C. It is set to become gradually wider in the order of. Each digital signal processing unit 4 selects any one of the analog units 3A, 3B, and 3C and uses the satellite signal processed by the selected analog unit. That is, each digital signal processing unit 4 selects the analog unit 3A when capturing the satellite signal, selects the analog unit 3B when tracking the satellite signal, and particularly when tracking the satellite signal with high accuracy. The analog unit 3C is selected.

[Embodiment 2]
FIG. 2 is a block diagram of electrical connection of the positioning device 1 according to the second embodiment.

  The positioning apparatus 1 includes, for example, an antenna 2 that receives a satellite signal transmitted from a satellite such as a GPS satellite, an analog unit 3 that performs analog processing of the received signal of the antenna 2, and a satellite signal that is processed by the analog unit 3. A plurality of digital signal processing units 4 that perform digital processing, a positioning calculation unit 5 that measures the current position of the antenna 2 based on the output result of each digital signal processing unit 4, and a positioning calculation unit 5 that uses road map data And a navigation unit 7 for displaying the current position of the antenna 2 obtained in step 1 on the map by the display 6.

  The analog unit 3 performs the following processing. That is, for example, since a satellite signal of a GPS satellite has a frequency of 1.5 GHz, processing is performed to reduce the frequency to 3.9 MHz so that the positioning device 1 can easily process the signal. Also, a filtering process is performed to cut out a noise component outside the extra band included in the satellite signal.

  The plurality of digital signal processing units 4 are digital signal processing units of channel 0 (ch0), channel 1 (ch1),..., Channel X (chX), respectively, and each channel corresponds to each satellite. Each digital signal processing unit 4 includes a plurality of, in this example, three capture / tracking units 11A, 11B, and 11C. The acquisition / tracking units 11A, 11B, and 11C perform acquisition (search) of the satellite signal and tracking (tracking) of the acquired satellite signal.

  The PN code generation unit 21 of the capture / tracking units 11A and 11B generates a plurality of PN codes whose phases are gradually shifted. The forming code generator 22 of the capturing / tracking unit 11C generates a forming code (details will be described later) instead of the PN code.

  The correlator 23 of the capture / tracking units 11A, 11B, and 11C captures the satellite signal by correlating the PN code or shaped code generated by the PN code generating unit 21 or the shaped code generating unit 22 with the satellite signal, respectively. Do.

  The normal tracking control unit 24 of the acquisition / tracking unit 11A, the strong filter tracking control unit 25 of the acquisition / tracking unit 11B, and the multipath suppression control unit 26 of the acquisition / tracking unit 11C all track the acquired satellite signal.

  Here, particularly in urban areas, tracking points may fluctuate carelessly due to the influence of multipath (a reflected wave of a satellite signal reflected by a building or the like). Therefore, the tracking control is generally performed by applying a low-pass filter to the control value for the correlation value so as not to track the fluctuation due to the multipath of the tracking point. As a result, it is possible to average the fluctuations of the multipaths so that the tracking point does not track even though the tracking points change due to the multipaths.

  However, the moving amount of the moving body provided with the antenna 2 is large. Therefore, when the tracking point actually moves greatly, if the low-pass filter is strongly applied, the response characteristic is deteriorated and the tracking is delayed.

  Therefore, the capture / tracking unit 11A, the capture / tracking unit 11B, and the capture / tracking unit 11C have different degrees of suppression of the influence of multipath in the tracking control. That is, the capturing / tracking unit 11A minimizes the degree of suppression of the multipath effect by not using a low-pass filter or by applying a weak low-pass filter. Therefore, even if the moving amount of the mobile body provided with the antenna 2 is large, the tracking can be prevented from being delayed, which is superior to the other capturing / tracking units 11B and 11C. The capturing / tracking unit 11B applies a low-pass filter stronger than the capturing / tracking unit 11A, thereby increasing the degree of suppression of the influence of the multipath than the capturing / tracking unit 11A. The capturing / tracking unit 11C can suppress the influence of the multipath more strongly than the capturing / tracking unit 11B by using a forming code that is a PN code capable of suppressing the influence of multipath (the forming code used here) As an example, see, for example, those disclosed in JP-A-2001-274727. Therefore, it is possible to prevent tracking even if the tracking point fluctuates due to multipath.

  Thus, each digital signal processing unit 4 includes three capture / tracking units 11A, 11B, and 11C. Then, which capture / tracking unit is used is selected by the selection unit 27, and the tracking point obtained by the currently selected capture / tracking unit is transmitted to the positioning calculation unit 5. Hereinafter, a plurality of examples of selection criteria in the selection unit 27 will be described.

(1) Selection criteria 1
When the signal intensity level obtained by each correlation unit 23 of the acquisition / tracking units 11A, 11B, and 11C is lower than a predetermined threshold value for each correlation unit 23, it is selected that tracking of the satellite signal has been removed. The capture / tracking unit is switched in the order of the capture / tracking unit 11C, the capture / tracking unit 11B, and the capture / tracking unit 11A.

  In other words, the capture / tracking unit 11C is selected which is usually least affected by multipaths in an urban area and has the least fear of deterioration in positioning accuracy.

  However, the acquisition / tracking unit 11C is least affected by the multipath, but uses a shaping code in which the bandwidth of the satellite signal from which the correlation is obtained by the correlation unit 23 is narrowly limited. If the correlation changes outside the band where the correlation cannot be obtained by the correlator 23, the signal power cannot be obtained and the tracking of the satellite signal is removed. .

  Therefore, when the signal intensity of the correlation unit 23 of the acquisition / tracking unit 11C falls below the threshold value prepared by the acquisition / tracking unit 11C, the acquisition / tracking unit 11C determines that the tracking of the satellite signal has been removed. To the capture / tracking unit 11B. In this case, the tracking point information obtained by the capturing / tracking unit 11B is also transmitted to the capturing / tracking unit 11C, and the capturing / tracking unit 11C performs tracking control using the tracking point obtained by the capturing / tracking unit 11B. fix.

  However, since the capture / tracking unit 11B uses a relatively strong low-pass filter so that it is difficult to track fluctuations in noise such as multipath, the moving body provided with the antenna 2 is further moving, When the signal strength of the correlation unit 23 of the acquisition / tracking unit 11B falls below the threshold prepared by the acquisition / tracking unit 11B, the acquisition / tracking unit 11B determines that the tracking of the satellite signal has been removed, Switch to the capture / tracking unit 11A. In this case, the tracking point information obtained by the capture / tracking unit 11A is also transmitted to the capture / tracking units 11C and 11B, and the capture / tracking units 11C and 11B use the tracking points obtained by the capture / tracking unit 11A. Perform tracking control again.

  Note that the capture / tracking units 11C and 11B can detect the satellite signal of the capture / tracking unit 11A when the capture / tracking unit 11A is switched from the supplement of the satellite signal to the tracking even in the initial stage of the operation of the positioning device 1. The tracking point is acquired and the satellite signal is tracked respectively.

(2) Selection criteria 2
The frequency (Doppler frequency) of the satellite signal affected by the Doppler effect with respect to the distance (pseudo distance) from the antenna 2 to the satellite obtained by tracking the satellite signal is relatively less affected by multipath.

  Therefore, in each of the acquisition / tracking units 11A, 11B, and 11C, it is determined which of the measured pseudorange changes is close to the measured Doppler frequency, and the closest one is selected.

  That is, “| change in pseudorange measured by the capture / tracking unit 11A—Doppler frequency measured by the capture / tracking unit 11A” is defined as a difference A, and “| change in pseudorange measured by the capture / tracking unit 11B—capture The difference A is the Doppler frequency | measured by the tracking unit 11B as the difference B, and the change in the pseudo distance measured at the | acquisition / tracking unit 11C-the Doppler frequency | When the difference C is the smallest among the differences B and C, for example, the capturing / tracking unit 11C is selected.

  Note that the capture / tracking units 11C and 11B can detect the satellite signal of the capture / tracking unit 11A when the capture / tracking unit 11A is switched from the supplement of the satellite signal to the tracking even in the initial stage of the operation of the positioning device 1. The tracking point is acquired and the satellite signal is tracked respectively.

(3) Selection criteria 3
Here, as shown in FIG. 3, a provisional positioning calculation unit 31 and a pseudo distance change estimation unit 32 are further provided in the configuration of FIG. 2.

  First, the provisional positioning calculation unit 31 acquires the Doppler frequency measured by the capturing / tracking unit 11A of each channel, and the speed (temporary speed) of the moving body provided with the antenna 2 is obtained from the Doppler frequency acquired from each channel. calculate.

  Next, the pseudo distance change estimation unit 32 performs a reverse calculation of the positioning calculation from the temporary speed calculated by the temporary positioning calculation unit 31 to estimate the change of the pseudo distance in each channel.

  Then, the selection unit 23 compares the change in the pseudo distance in each channel estimated by the pseudo distance change estimation unit 32 with the change in the pseudo distance measured in each capture / tracking unit 11A, 11B, 11C in each channel. Then, it is determined which of the pseudo distance changes measured by the respective capture / tracking units 11A, 11B, and 11C is the closest to the pseudo distance change estimated by the pseudo distance change estimation unit 32. For example, when the capture / tracking unit 11C is closest to the pseudo distance change estimated by the pseudo distance change estimation unit 32 among the pseudo distance changes measured by the respective capture / tracking units 11A, 11B, and 11C. Transmits the pseudo distance and the Doppler frequency measured by the capturing / tracking unit 11C to the positioning calculation unit 5, and calculates the position and speed of the moving body provided with the antenna 2.

  Note that when the vehicle speed pulse or the direction sensor detection signal is obtained from the moving body, the speed of the moving body can be known from these, so the provisional speed calculation unit 31 is not provided as shown in FIG. Instead of this, a vehicle speed pulse and a direction sensor detection signal may be transmitted to the pseudo-range change estimating unit 32.

  Note that the capture / tracking units 11C and 11B can detect the satellite signal of the capture / tracking unit 11A when the capture / tracking unit 11A is switched from the supplement of the satellite signal to the tracking even in the initial stage of the operation of the positioning device 1. The tracking point is acquired and the satellite signal is tracked respectively.

[Embodiment 3]
FIG. 5 is a block diagram of electrical connection of the positioning device 1 according to the third embodiment.

  The positioning device 1 includes, for example, an antenna 2 that receives a satellite signal transmitted from a satellite such as a GPS satellite, an analog unit 3 that performs analog processing on the received signal of the antenna 2, and a satellite signal that is processed by the analog unit 3. A plurality of digital signal processing units 4 that perform digital processing and a plurality of positioning operation units 5A, 5B, and 5C in this example that measure the current position of the antenna 2 based on the output result of each digital signal processing unit 4 And a navigation unit 7 that displays the current position of the antenna 2 obtained by any one of the positioning calculation units 5A, 5B, and 5C using the road map data on the map by the display 6.

  The analog unit 3 performs the following processing. That is, for example, since a satellite signal of a GPS satellite has a frequency of 1.5 GHz, processing is performed to reduce the frequency to 3.9 MHz so that the positioning device 1 can easily process the signal. Also, a filtering process is performed to cut out a noise component outside the extra band included in the satellite signal.

  The plurality of digital signal processing units 4 are digital signal processing units of channel 0 (ch0), channel 1 (ch1),..., Channel X (chX), respectively, and each channel corresponds to each satellite. Each digital signal processing unit 4 captures (searches) a satellite signal and tracks (tracks) the captured satellite signal. That is, the digital signal processing unit 4 generates a plurality of PN codes whose phases are gradually shifted, and captures satellite signals by correlating the PN codes with the satellite signals. Then, the captured satellite signal is tracked.

  Each positioning calculation unit 5A, 5B, 5C calculates the speed and position of the moving body provided with the antenna 2 from the pseudo distance and Doppler frequency measured in each channel. The influence of the multipath is determined from the positioning speed. Therefore, filtering by a filter (velocity filter) that smoothes the positioning position with a positioning speed that suppresses the fluctuation of the positioning position to the positioning speed and reduces the influence of multipath is usually performed.

  However, sometimes the positioning speed also becomes an error due to the influence of multipath, and an erroneous positioning position may be obtained instead because a filter is applied or a filter is applied strongly. In this case, the change in the influence of the multipath is severe, and it is difficult to adjust the speed filter to the optimum strength according to the situation.

  Therefore, the positioning calculation unit 5A does not filter the positioning speed, the positioning calculation unit 5B filters the positioning speed, and the positioning calculation unit 5C filters the positioning speed more strongly than the positioning calculation unit 5B. The navigation unit 7 selects any one of the positioning calculation units 5A, 5B, and 5C.

  The selection of the vigation unit 7 here is performed with reference to the history information of the position of the moving body provided with the antenna 2, the vehicle speed pulse, the direction sensor detection signal, the road map information used for navigation, and the like.

  Specifically, when any one of the positioning calculation units 5A, 5B, and 5C is selected and the positioning position is deviated from the position on the road in the road map information, another positioning calculation is performed. Select any one of the units 5A, 5B, 5C. When the positioning position is greatly deviated from the result of the detection signal of the vehicle speed pulse and the direction sensor, the positioning unit 5A, 5B, 5C One of them is selected.

DESCRIPTION OF SYMBOLS 1 Positioning device 3, 3A, 3B, 3C Analog part 4, 4A, 4B, 4C Digital signal processing part 5, 5A, 5B, 5C Positioning calculation part 11A, 11B, 11C Acquisition and tracking part 27 Selection part 31 Temporary positioning calculation part 32 Pseudo distance change estimation part

Claims (7)

An antenna,
A plurality of processing means for performing a process of cutting out-of-band noise components for each satellite signal received by the antenna;
Selecting means for selecting one of the plurality of processing means;
Acquisition / tracking means for acquiring and tracking the satellite signal processed by the processing means selected by the selection means;
Positioning means for performing positioning based on the captured and tracked satellite signals;
With
The plurality of processing means have different bandwidths from each other,
The selecting means selects one of the plurality of processing means according to the processing performed by the capturing / tracking means;
Positioning device. An antenna,
A plurality of capturing / tracking means for capturing and tracking the satellite signal for each satellite signal received by the antenna;
Selecting means for selecting one of the plurality of capturing / tracking means;
Positioning means for performing positioning based on the satellite signals captured and tracked by the capturing / tracking means selected by the selection means;
With
The plurality of capturing / tracking means have different degrees of multipath suppression,
Positioning device.   The selection means is configured to select one of the plurality of acquisition / tracking means based on a comparison between a predetermined threshold value for each of the acquisition / tracking means and a signal strength of the satellite signal obtained by the acquisition / tracking means. The positioning device according to claim 2, wherein one is selected.   The positioning device according to claim 2, wherein the selection unit selects one of the plurality of acquisition / tracking units based on a difference between a change in pseudo distance in each of the acquisition / tracking units and a Doppler frequency. .   The selection means obtains a pseudo distance from the speed of the antenna, and based on a comparison between the pseudo distance and the pseudo distance obtained by each of the acquisition / tracking means, one of the plurality of acquisition / tracking means is selected. The positioning device according to claim 2, wherein one is selected. An antenna,
A plurality of capturing / tracking means for capturing and tracking a satellite signal received by the antenna;
A plurality of positioning means for positioning the position and speed of the antenna based on the satellite signals captured and tracked by the capturing / tracking means;
Selecting means for selecting one of the plurality of positioning means;
Navigation means for performing navigation based on the position and speed measured by the positioning means selected by the selection means;
With
The plurality of positioning means have different degrees of filtering,
The selection means selects one of the plurality of positioning means according to the processing performed by the navigation means;
Positioning device.   The positioning device according to claim 6, wherein the plurality of positioning means have different degrees of filtering performed on the positioning speed.

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