JP5244490B2 - GPS positioning apparatus and method therefor - Google Patents

Description

  The present invention relates to a GPS position specifying device that specifies a current position based on radio waves from GPS obtained by a GPS receiver, and in particular, for realizing high-precision positioning by reducing errors due to multipath components. The present invention relates to a GPS positioning apparatus and a method therefor.

  A so-called GPS positioning device that receives a signal from a satellite called GPS and identifies (positions) a current position of a moving object or the like is used in various fields including navigation of automobiles.

  By the way, in such GPS positioning, a positioning error caused by a multipath component due to radio wave reflection or the like is already known, and conventionally, for example, a plurality of reference stations are used as known in the following patent documents. It is already known that the accuracy of the DGPS correction data is improved, thereby improving the accuracy of positioning. Also, conventionally, by comparing the received signal strength from the satellite at each of the reference station and the mobile station, it is possible to determine whether the received signal from the satellite includes a multipath component (error). The determination method is already known.

JP 2002-122652 A

  However, in the above-described conventional technology, it is determined whether or not the above multipath component is included by comparing the strengths of the satellite signals received by a plurality of base stations or the reference station and the mobile station. Therefore, in order to accurately compare the signal strengths, it is necessary to use the same GPS signal processing unit and GPS antenna in a plurality of base stations, or a reference station and a mobile station. There are restrictions such as the need to connect a plurality of base stations or a reference station and a mobile station at high speed via a network or the like.

  Therefore, the present invention has been achieved in view of the above-described problems in the prior art. The object of the present invention is to use only received data obtained from a single (single) GPS receiver, while still It is an object of the present invention to provide a position specifying device that can determine a path component (error) and improve positioning accuracy, and a method therefor.

  That is, in the present invention, the positioning performance of GPS is greatly improved by the relative positioning GPS and the like, but the deterioration of the positioning performance of the GPS due to multipath, which is a problem that cannot be removed by the relative positioning GPS technology. By using the pseudo-range included in the received data obtained by the GPS signal processing unit, in particular, the amount of change, it is possible to determine that the received radio signal includes a multipath component. The present invention provides a position specifying device that can improve the position accuracy capable of positioning alone and a method therefor.

  More specifically, according to the present invention, in order to achieve the above object, first, a GPS position specifying device capable of receiving radio waves from a plurality of GPS satellites and specifying the position independently is provided. A GPS receiver that receives radio waves from a plurality of GPS satellites, and a GPS signal that outputs satellite data including at least a pseudo distance to each of the plurality of GPS satellites from the radio waves received by the GPS receiver. The pseudorange is extracted from satellite data for each satellite obtained from the processing unit and the GPS signal processing unit, the presence / absence of a multipath component included in the pseudorange is determined, and the presence / absence of the multipath component is determined. And a GPS data processing unit that performs processing calculation for the pseudorange and performs position calculation processing using satellite data including the pseudorange. Localization device is provided.

  Further, according to the present invention, in order to achieve the above object, a GPS receiving unit that receives radio waves from a plurality of GPS satellites, and a radio wave received by the GPS receiving unit, to each of the plurality of GPS satellites. On the other hand, a GPS signal processing unit that outputs satellite data including at least a pseudo-range, and a GPS position specifying device provided alone, receives radio waves from the plurality of GPS satellites and specifies their positions. A position specifying method, the step of extracting the pseudo distance from the satellite data for each satellite obtained from the GPS signal processing unit, and the step of determining the presence or absence of a multipath component included in the extracted pseudo distance A step of determining a processing for the pseudo distance based on the determination of the presence or absence of the multipath component, and a satellite including the pseudo distance GPS position determination method and a step of performing position calculation process using the chromatography data is provided.

  In addition, according to the present invention, in the GPS position specifying apparatus and method described above, using the pseudorange extracted for each satellite, the difference between the pseudorange acquired last time and the pseudorange acquired this time, and the past difference It is preferable to calculate the amount of change from the average value of and to determine whether or not a multipath component is included in the pseudorange for each satellite based on the amount of change. Furthermore, when it is determined that the multipath component is not included in the pseudo distance, the pseudo distance is output as it is, or when it is determined that the multi distance component is included in the pseudo distance. Removes the data from the satellite, removes the pseudorange, or performs an interpolation process by adding an average value of past differential distances to the previous pseudorange, and performs a position calculation process using the satellite data. Preferably it is done.

  According to the above-described GPS position identification device and method according to the present invention, even when the device is installed alone, high-accuracy position information is acquired by preventing the degradation of positioning performance due to multipath errors. This will also provide a practically excellent effect of being possible.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  First, an overall configuration of a position specifying apparatus according to an embodiment of the present invention will be described with reference to FIG. In the figure, reference numeral 101 denotes a GPS antenna for receiving signals from a plurality of satellites called GPS (not shown here), and the radio signal received by the GPS antenna 101 is Then, predetermined signal processing is performed by the GPS signal processing unit 102, and each of the plurality of satellites i (i = natural number = 1, 2, 3,...) Is output as respective data, that is, satellite data. The data from the plurality of satellites (satellite data 1, satellite data 2,...) Are each subjected to processing for determining the presence or absence of multipath components in the GPS data processing unit 103 described in detail below. By performing the necessary correction, the position is calculated, and the positioning result is output and stored in the information recording device 110 such as a memory.

  The GPS antenna 101 and the GPS signal processing unit 102 described above are generally available in the market as GPS receivers (for example, model OEMCEM IV manufactured by NoVAtelNOVAtel, GB-1000 manufactured by TOPCON, etc.). It would be possible to adopt it. Further, satellite data 1, satellite data 2,... Obtained by receiving radio signals from the above-mentioned satellites are data before correction for each satellite obtained from such a device, as will be described below. This is so-called raw data, and in particular, pseudo distance.

  Next, in the following, the principle of the data processing executed in the GPS data processing unit 103 described above, particularly the processing for determining the presence / absence of a multipath component using the pseudorange for each satellite will be described with reference to the accompanying drawings. 3 to 5 will be described.

  First, in FIG. 3 attached, for example, when the position specifying device of the present invention is mounted on a so-called moving body such as a train, pseudo distances (Pd0, Pd1, Pd2) and a difference distance (Pd1-Pd0, The relationship with Pd2-Pd1) is shown. That is, with respect to a certain satellite among a plurality of satellites i (i = natural number = 1, 2, 3,...), A pseudo distance (Pd0 to Pd2) at different times and a difference distance (Pd1−Pd0, Pd2−Pd1), that is, the presence or absence of multipath components is determined by extracting the difference.

  Next, extraction of the change amount of the pseudo distance will be described with reference to FIG. That is, the difference distance 402 (B = Pd1−Pd0) extracted this time and the difference distance 401 obtained by averaging the difference distances obtained at a plurality of past points in time (that is, the average value up to the nearest difference distance held: A) is used to extract the pseudo distance change amount 403 (pseudo distance change amount C) using the calculation formula 404 (C = B−A). Thereafter, the obtained change amount C of the pseudo distance is compared with a predetermined threshold value for determination. As a result, when the change amount C of the pseudo distance is larger than the threshold value, it is determined that a multipath component exists in the radio wave received from the satellite. On the other hand, when the change amount C is smaller than the threshold value, It is determined that no multipath component exists. That is, based on the determination of the presence of the multipath component, it is determined whether or not the pseudo distance obtained this time is appropriate for use for position measurement.

  Further, with reference to FIG. 5, the pseudo distance interpolation process when the value of C, which is the pseudo distance change amount, is larger than the threshold value will be described. That is, in this case, the pseudo distance obtained this time is determined to be unsuitable for use for position measurement based on the determination of the presence of the multipath component. If the number of pseudoranges obtained from multiple satellites is insufficient to perform subsequent position measurements due to the presence of multipath components, the pseudorange obtained this time is replaced. Thus, the interpolated pseudo distance (Pt2_new) 502 is obtained by adding the average value A up to the nearest difference distance to the previous pseudo distance (Pt_old1) 501. That is, according to such an interpolation calculation, it is possible to secure a necessary number of pseudo distances even when it is determined to be inappropriate due to the presence of a multipath component. Thereafter, the previous pseudo distance (Pt_old1) is updated to the previous pseudo distance (Pt_old2) 503 after the interpolation based on the calculated result. Thus, by updating the previous pseudo distance 503 after interpolation after interpolation, it can be used for the next difference distance extraction.

  Subsequently, based on the principle of processing for determining the presence or absence of the multipath component described in detail above, the data for each satellite (satellite data 1, satellite data 2...) Obtained from the GPS signal processing unit 102 is used. Details of the GPS data processing unit 104 for processing a pseudo distance will be described in detail below.

  That is, the GPS data processing unit 103 that processes the pseudoranges receives the data for each satellite (satellite data 1, satellite data 2,...) From the GPS signal processing unit 102 as is apparent from the figure, and Using the pseudorange extraction unit 104 for extracting the pseudorange and the pseudodistance extracted by the pseudodistance extraction unit, and based on the above-described determination principle, a multipath component exists in the radio wave from each satellite. A determination processing unit 105 for determining whether or not, and various determination parameters (for example, threshold information, difference distance 401 obtained by averaging difference distances obtained at a plurality of past points) used in the above-described determination principle. That is, the memory device 106 for storing the average value of the difference distance up to the latest (including A and the like), and the result of the above determination, the multipath to the influence satellite, that is, the radio wave from the satellite Therefore, the influence satellite removal / interpolation processing unit 107 for performing the interpolation processing described above and the influence satellite removal / interpolation are also removed. A data output unit 108 that outputs data for each processed satellite from the processing unit, and a position calculation processing unit 109 that performs position calculation processing based on data (data for each processed satellite) output from the data output unit. It is configured. More specifically, the GPS data processing unit 103 is configured by, for example, a microcomputer.

  Next, detailed operation of each part in the position specifying device including the GPS data processing unit 103 having the above-described configuration will be described with reference to FIG. 1 described above.

  (1) First, for each of a plurality of satellites, the data for each satellite (satellite data 1, satellite data 2,...) Output by the GPS signal processing unit 102 based on the radio signal received by the GPS antenna 101 is converted into the GPS data. The data is output to the processing unit 103.

  (2) The pseudorange extraction unit 104 extracts pseudoranges from the satellite data specified in the previous section (1). The extracted data is passed to the determination processing unit 105.

  (3) The determination processing unit 105 calculates the difference between the pseudo distance acquired last time and the pseudo distance acquired this time, calculates the difference averaged in the past, and extracts the change amount of the pseudo distance.

  (4) Using the threshold information acquired from the memory 106 that stores the determination parameters, the amount of change in the extracted pseudorange is compared. If the change is greater than the threshold, the satellite data includes a multipath component. It is determined that the data is from a satellite (see FIG. 4 above).

  (5) The determination result in (4) above is passed to the influence satellite removal and interpolation processing unit 107 as influence satellite information. Here, data from satellites other than those determined to contain a multipath component are used for update processing of an average (so-called smoothing process) value of the difference distance in the past.

  (6) On the other hand, data from satellites that have been determined to have multipath components are removed.

  (7) Furthermore, in the interpolation process, the pseudorange is interpolated by adding the past average value of the difference distance to the previous pseudorange for the data of the satellite that has been determined to have multipath components. Processing is performed (see FIG. 5 above).

  (8) For satellite data that has been judged to have multipath components, add the past average value of the difference distance to the previous pseudorange, and hold the interpolated pseudorange as the previous pseudorange data. To do.

  (9) For satellites that have been determined to have multipath components, the satellite data for which the above processing has been completed is output to the arithmetic processing unit 109 via the data output unit 108.

  (10) The arithmetic processing unit 109 performs position calculation processing using data for each satellite by predetermined arithmetic processing, and outputs the positioning result to the information recording device 110 such as a memory, for example. To store.

  In addition, the processing procedure of the operation in the GPS data processing unit 103 described in detail above will be described below with reference to the flowchart of FIG.

  (1) In FIG. 2, the GPS data processing unit 103 starts processing (S201).

  (2) The processing determination unit 104 determines multipath components (S202), and designates a processing method for satellite data for each satellite based on the result. That is, when it is determined that the multipath component does not exist in the radio wave from the satellite in the processing determination (S203) by the processing determination unit, that is, when it is not necessary to perform the above-described processing, The satellite data is transferred to the data output unit 108 (S203). On the other hand, in the processing determination (S203), when removing due to the presence of the multipath component, the satellite data is removed (S204), and the satellite data is passed to the data output unit 108 (S206). At this time, when the pseudo distance is obtained by interpolation regardless of the presence of the multipath component, the pseudo distance interpolation process shown in FIG. 5 is performed (S205), and the data obtained by the interpolation is obtained. The data is output to the data output unit 108 (S206). The above processing is continuously performed for each of a plurality of satellites i (i = natural number = 1, 2, 3,...) Capable of receiving the radio wave by the position specifying device.

  As described above in detail, according to the present embodiment, even when the apparatus is installed alone, degradation of GPS positioning performance due to multipath can be reduced, and thus high position accuracy can be maintained. A GPS position specifying device capable of performing the above will be obtained.

It is a block diagram which shows the whole structure of the GPS position identification apparatus which becomes one embodiment of this invention. It is a processing flowchart which shows the detail of the process in the said GPS position specific apparatus especially the GPS data process part. It is a figure explaining the differential distance extraction method of a pseudo distance for demonstrating the principle of the multipath component determination process in this invention. It is a figure explaining the variation extraction method of a pseudo distance for demonstrating the principle of the multipath component determination process in this invention. Furthermore, it is a figure explaining the interpolation method of the pseudo distance when a multipath component exists.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 GPS antenna 102 GPS signal processing part 103 Position identification apparatus 104 Pseudo distance extraction part 105 Judgment processing part 106 Memory for determination parameter storage 107 Influence satellite removal and interpolation processing part 108 Data output part 109 Position calculation process 110 Memory for positioning result storage .

Claims (4)

A GPS position specifying device that receives radio waves from a plurality of GPS satellites and is capable of specifying a position alone,
A GPS receiver that receives radio waves from a plurality of GPS satellites;
A GPS signal processing unit that outputs satellite data including at least a pseudo distance to each of the plurality of GPS satellites from the radio wave received by the GPS receiving unit;
Extracting the pseudorange from the satellite data for each satellite obtained from the GPS signal processing unit, determining the presence or absence of a multipath component included in the pseudorange, based on the determination of the presence or absence of the multipath component, A GPS data processing unit that performs a processing process determination on the pseudo distance, and performs a position calculation process using satellite data including the pseudo distance ,
The GPS data processing unit uses the pseudo distance extracted for each satellite, calculates a change amount from the difference between the pseudo distance acquired last time and the pseudo distance acquired this time, and the average value of the past differences, Based on the amount of change, for each satellite, determine whether the pseudorange includes a multipath component,
When it is determined that the multipath component is included in the pseudo distance, the pseudo distance is removed, or an interpolation process is performed by adding an average value of past difference distances to the previous pseudo distance, A GPS position specifying apparatus that performs position calculation processing using the satellite data . 2. The GPS position specifying apparatus according to claim 1, wherein when the GPS data processing unit determines that the multipath component is not included in the pseudo distance, the pseudo distance is output as it is, and the satellite A GPS position specifying device that performs position calculation processing using data . A GPS receiver that receives radio waves from a plurality of GPS satellites, and a GPS signal processor that outputs satellite data including at least a pseudorange to each of the plurality of GPS satellites from the radio waves received by the GPS receiver. In a GPS position specifying device provided independently, a GPS position specifying method for receiving radio waves from the plurality of GPS satellites and specifying the position,
Extracting the pseudorange from satellite data for each satellite obtained from the GPS signal processing unit;
Determining the presence or absence of multipath components included in the extracted pseudorange;
Based on the determination of the presence or absence of the multipath component, the step of determining the processing for the pseudo distance, and
Performing position calculation processing using satellite data including the pseudorange,
In the multipath component presence / absence determination step, using the pseudorange extracted for each satellite, the amount of change is calculated from the difference between the pseudorange acquired last time and the pseudorange acquired this time, and the average value of the past differences. Then, based on the amount of change, for each satellite, determine whether the pseudo-range includes a multipath component,
When it is determined that the multipath component is included in the pseudo distance, the pseudo distance is removed, or an interpolation process is performed by adding an average value of past difference distances to the previous pseudo distance, A GPS position specifying method, comprising performing position calculation processing using the satellite data. 4. In the GPS position specifying method according to claim 3, when it is determined that a multipath component is not included in the pseudo distance, the pseudo distance is output as it is, and a position calculation process using the satellite data is performed. The GPS position specifying method characterized by performing.

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