JP2009053152A - Satellite positioning system, satellite positioning technique, and program and storage medium thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the effect on positioning results even if failure arises in one frequency, in a satellite positioning system and a satellite positioning technique both using a receiver with two different frequencies. <P>SOLUTION: After abnormalities in received signal at the two different frequencies input from an input device 20 are detected based on the difference of phase interval at an abnormal data detecting section 31 of a data processing device 30, the detected abnormal data are removed in an abnormal data removal section 32 of the data processing device 30 to output the pseudo interval and phase data to an output device 40. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a satellite positioning system and a satellite positioning method, and more particularly to a satellite positioning system, a satellite positioning method, a program thereof, and a storage medium using a two-frequency receiver.

  A satellite positioning system has been developed that receives radio waves emitted from multiple artificial satellites that orbit around a given orbit and obtains accurate position information, acquiring map data, monitoring crustal movements, and detecting the position of fixed or moving objects. It is widely used in many fields. A typical application example of the satellite positioning system is a GPS (Global Positioning System).

  Such satellite positioning systems or satellite positioning techniques are disclosed in various technical documents. A GPS receiver and a positioning method for detecting the reception of multipaths and reflected waves and removing abnormal positioning results are disclosed (for example, see Patent Document 1). In addition, satellite radio positioning using a two-frequency receiver that receives two predetermined high-accuracy frequencies is disclosed (for example, see Patent Document 2).

JP 2001-124840 A (Page 5-6, FIGS. 1 and 2) Japanese Patent Laid-Open No. 9-171071 (page 4, FIG. 1)

  In the satellite positioning system, a receiver capable of processing signals of two frequencies or wavelengths transmitted from each satellite (hereinafter referred to as a two-frequency receiver) is widely used in order to perform highly accurate positioning. Yes. The signal transmitted from the satellite includes pseudorange and phase data for each of the two wavelengths. In satellite positioning using such a two-frequency receiver, when the two satellites have different velocities when viewed from the two-frequency receiver, the signal strength of one satellite is greater than the other. In some cases, the frequency to be captured is confused due to being easily affected by radio wave interference. Similar phenomena can occur due to satellite or receiver failure. When such a phenomenon occurs, a large error is temporarily included in the pseudorange and phase data of one frequency, which greatly affects the positioning result.

  Abnormal data detection in the conventional satellite positioning system calculates the rate of change between the data of the "previous time" and the data of the "current time", and determines that this is abnormal when the rate of change exceeds a preset threshold. Yes. However, when this phenomenon occurs, the data of one frequency gradually shifts, so that there is no significant change in the difference (or rate of change) between the “previous time” data and the “current time” data. However, there is a problem that the abnormality detection method using the data change rate as an index cannot be detected.

  The present invention has been made in view of the above-described problems of the prior art, and includes a satellite positioning system and a satellite positioning method that eliminate or reduce such problems due to influences on measurement results due to receiver malfunctions, satellite malfunctions, and the like. And its program and storage medium.

The satellite positioning system of the present invention employs the following characteristic configuration. That is,
(1) In a satellite positioning system that obtains position data using a two-frequency receiver that receives a signal transmitted from a satellite,
An anomaly data detector that detects an anomaly in one of the two frequencies received by the two-frequency receiver based on a difference in phase distance that is the product of the phase and wavelength;
A satellite positioning system comprising: an abnormal data removing unit that removes abnormal data detected by the abnormal data detecting unit.

The satellite positioning method of the present invention employs the following characteristic configuration. That is,
(6) In a satellite positioning method for obtaining position data using a two-frequency receiver that receives a signal transmitted from a satellite,
A data abnormality detection step of detecting a data abnormality of one of the two frequencies based on a difference in phase distance between two frequency signals received by the two-frequency receiver;
A satellite positioning method including data processing comprising: an abnormal data removal step of removing and outputting abnormal data detected in the data abnormality detection step.

  According to the satellite positioning system and the satellite positioning method of the present invention, there are the following practical specific effects. That is, according to the satellite positioning system and the satellite positioning method of the present invention, the data of one frequency that can be generated in the satellite positioning calculation using two frequencies is gradually shifted and the positioning accuracy is deteriorated due to the abnormality. It can be effectively prevented. The reason is that at each time point, abnormal data is detected using an index calculated from the difference between the “phase distance” that is the product of the wavelength and phase of two frequencies, and the detected abnormal data is detected by the abnormal data removal unit. This is because it is removed and output to the output device.

  Hereinafter, the configuration and operation of a preferred embodiment of a satellite positioning system and a satellite positioning method according to the present invention will be described in detail with reference to the accompanying drawings.

  First, the satellite positioning system of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a system configuration of a preferred embodiment of a satellite positioning system according to the present invention. The satellite positioning system 10 includes an input device 20, a data processing device 30, and an output device 40. The data processing device 30 includes an abnormal data detection unit 31 and an abnormal data removal unit 32.

  In the satellite positioning system 10 shown in FIG. 1, the input device 20 receives data from a two-frequency receiver (not shown) that receives radio waves emitted by an artificial satellite (not shown) sequentially or on a recording medium such as a tape. This is a device that can read recorded LINEX in a batch. The data processing device 30 is a processing device such as a CPU (central processing unit) provided with a program for detecting and removing abnormal data from the phase and pseudorange of two frequencies input thereto. The output device 40 is a device such as a display, a storage device, and a recording medium for outputting the processing result of the data processing device 30. The data processing device 30 includes an abnormal data detection unit 31 that detects an abnormality of data input from the input device 20 and an abnormal data removal unit 32 that excludes abnormal data detected by the abnormal data detection unit 31.

  The abnormal data detection unit 31 of the data processing device 30 determines whether the data is abnormal data from the phase of the input signal from the input device 20. The determination of the abnormal data is performed, for example, by calculating a difference between the product of the phase and wavelength of the first frequency (hereinafter referred to as phase distance) and the phase distance of the second frequency and examining the change. The abnormal data removing unit 32 removes the abnormal data detected by the abnormal data detecting unit 31, and the “pseudo distance” (distance between the satellite and the receiving engine that may include various errors) and the phase of the two frequencies after the abnormal data is removed. Is output to the output device 40.

  Next, the operation of the embodiment of the satellite positioning system 10 according to the present invention shown in FIG. 1 will be described in detail with reference to the flowchart of FIG. The pseudoranges and phases of the two frequencies input from the input device 20 of the satellite positioning system 10 are supplied to the data processing device 30. Then, the abnormal data detection unit 31 performs “abnormal data detection processing” for the supplied pseudo distance and phase as described below.

First, the pseudorange and phase of each frequency are read (step A1). Next, an index for detecting abnormal data is calculated (step A2). An index for detecting abnormal data is calculated based on, for example, [Equation 1]. In this calculation, in order to remove the influence of noise, the total value (IBASE) of the phase distance difference of data that is not abnormal data from the start of processing to the previous time is used. For a certain number of epochs from the process start epoch, a sufficient number of epochs for the calculation of IBASE cannot be secured, and the process proceeds to detection of abnormal data (step A5). The number of epochs for which this calculation is not performed can be, for example, 10 epochs, but other values may be set based on observation values.

  Next, it is determined whether it is abnormal data (step A3). In this abnormal data determination, when the index can be calculated, it is confirmed whether or not the calculated index exceeds a predetermined threshold value. The threshold value can be set to 1.5 m, for example. However, other values may be set based on the observed values. If the data exceeds the threshold and the data is abnormal (step A3: YES), it is determined as abnormal data, and the pseudorange and phase of the epoch are removed as “abnormal data” (step A4). If the data is not abnormal (step A3: NO), it is determined whether all data has been processed (step A5). If all the data has been processed (step A5: YES), the processing ends because all the data processing has been completed (step A6). If all data processing has not been completed (step A5: NO), the process returns to step A1 described above, and the above steps are repeated.

  From the abnormal data removing unit 32 of the data processing device 30, the pseudorange and phase of the two frequencies of the first frequency and the second frequency from which the abnormal data has been removed are supplied to the output device 40.

  Next, with reference to FIGS. 3 and 4, the effect of preventing the deterioration of the positioning accuracy in the satellite positioning system and the satellite positioning method according to the present invention will be described in detail. First, FIG. 3 is a graph showing a difference in phase distance between two frequencies in a normal state. In FIG. 3, the horizontal axis represents time, and the vertical axis represents the difference in phase distance. As shown in FIG. 3, in the normal state, the absolute value of the phase distance is different for each frequency, but the rate of change, that is, the difference in phase distance (calculated value at each time) is a substantially constant value.

  On the other hand, FIG. 4 shows a state (abnormal state) in which data of one of the two frequencies becomes abnormal. In this abnormal state, it can be confirmed that the change rates of the respective phase distances are different. Therefore, when one of the two frequencies becomes abnormal data, it is detected by determining whether the index for detecting abnormal data in [Equation 1] exceeds a predetermined threshold. It becomes possible to do. In the calculation of the index of [Equation 1], in order to remove the influence of noise included in the phase distance difference, it is not abnormal data from the start of processing to the previous epoch, that is, the difference from the average value of normal data is taken. The possibility of false detection is reduced.

Next, a second embodiment of the satellite positioning system and the satellite positioning method according to the present invention will be described. The system configuration of this embodiment is not shown because it is the same as that of the first embodiment described above. The second embodiment is different in that [Equation 2] is used instead of [Equation 1] used in the above-described first embodiment in order to detect and remove abnormal data in data processing.

  [Equation 2] calculates an interpolation function for the difference in phase distance shown in [Equation 1] using a predetermined number of epochs up to the previous epoch, and adds the current time to the interpolation function. By substituting, an estimated value of the difference in phase distance at the current time is calculated and used as an index. Such an interpolation function can be calculated, for example, by applying the least square method using, for example, an epoch five times before the current time, but can also be calculated by other methods.

  FIG. 5 shows a time-series graph of the difference in phase distance in the second embodiment. The interpolating function is calculated from the values of the five epochs up to the previous epoch in FIG. The difference from the “measured value” that is the measured value of is an index.

  According to the positioning method using the difference between the “estimated value” and the “measured value” as an index, the threshold value is calculated with fewer epochs than the positioning method of the first embodiment described above. Therefore, the effect of increasing the detection sensitivity of abnormal data can be expected.

Next, a third embodiment of the satellite positioning system and the satellite positioning method according to the present invention will be described. In the third embodiment, it is possible to adopt the same system as in the first embodiment described above, except that [Equation 3] is used instead of [Equation 1] used for data processing. This [Equation 3] calculates the difference D1 between the “pseudo distance” and the “phase distance” at one frequency and the difference D2 between the “pseudo distance” and the “phase distance” at the other frequency. Then, abnormal data is detected from the change in the difference between D1 and D2.

  In the calculation for detecting abnormal data, in order to remove the influence of noise, the total value (IBASE) of the difference between “pseudo distance” and “phase distance” of data that is not abnormal data from the start of processing to the previous time. Is used. With respect to a certain number of epochs from the process start epoch, a sufficient number of epochs for the calculation of IBASE cannot be secured, so that abnormal data is not detected and the process proceeds to step A5 in the flowchart of FIG. The number of epochs for which this calculation is not performed can be 10 epochs, for example. However, other values may be set based on the observed values. When the index calculated from [Expression 3] exceeds the threshold, the epoch pseudorange and phase are invalidated. The threshold value can be set to 10 m, for example, but other values may be set.

  According to the positioning method of the third embodiment, since the “pseudo distance” is used for calculation of an index for detecting an abnormal value as compared with the positioning method of the first embodiment described above, the “pseudo distance” is Even if an abnormality occurs, it can be detected.

  Each step of the satellite positioning method according to the present invention described above with reference to the flowchart of FIG. 2 and [Equation 1] to [Equation 3] is also applied to a computer-executable program or a storage medium storing such a program. Is possible.

The satellite positioning system and the satellite positioning method according to the present invention have been described in detail based on the preferred embodiments. However, it should be noted that such examples are merely illustrative of the invention and do not limit the invention in any way. Those skilled in the art will readily understand that various modifications and changes can be made in accordance with a specific application without departing from the gist and spirit of the present invention. The present invention is applicable to any satellite positioning system and satellite positioning method using a two-frequency receiver. For example, the embodiment of the present invention can be expressed as the following configuration in addition to the configurations (1) and (6) in the means for solving the problems.
(2) In a satellite positioning system that obtains position data using a two-frequency receiver that receives a signal transmitted from a satellite,
An input device for reading data from the two-frequency receiver;
A data processing device for processing data output from the input device;
An output device for displaying and storing the output of the data processing device,
The data processing device removes abnormal data detected by the abnormal data detection unit and abnormal data detected by the abnormal data detection unit that detects abnormal data from the phase and pseudorange of each of the two frequencies input from the input device and outputs the data An abnormal data output unit that outputs the pseudorange and phase of the two frequencies to the device;
A satellite positioning system that outputs pseudorange and phase data from the abnormal data removal unit of the data processing device to the output device.
(3) The satellite positioning system according to (1) or (2), wherein the abnormal data is detected by the abnormal data detection unit based on an index obtained by a calculation formula.
(4) The satellite positioning system according to (1) or (2), wherein the abnormal data detection unit sequentially receives data from the two-frequency receiver.
(5) The satellite positioning system according to (1) or (2), wherein the abnormal data detection unit collectively receives LINEX format files recorded on a recording medium.
(7) The abnormal data detection step of the data processing includes an index based on a reading step of reading the phase distance and phase of the two frequencies, and a difference between the phase distance of one of the two frequencies and the phase distance of the other frequency. And (6) the satellite positioning method including the step of calculating.
(8) The calculation of the index for detecting the abnormal data uses the total value of the phase distance differences of normal data of a predetermined constant epoch number from the start of the data processing to the previous time. (7) Satellite positioning method.
(9) The satellite positioning method according to (7), wherein an estimated value based on an interpolation function of a predetermined constant epoch number is used for calculating the index for detecting the abnormal data.
(10) In calculating the index for detecting the abnormal data, the difference between the pseudorange and phase distance of one of the two frequencies and the difference between the pseudorange and phase distance of the other frequency are obtained. Satellite positioning method.
(11) A program that allows a computer to execute the steps of the satellite positioning method according to any one of (6) to (10).
(12) A storage medium storing the program of (11) so that the computer can read it.

1 is a block diagram showing a schematic system configuration of a satellite positioning system according to the present invention. It is a flowchart explaining operation | movement of the satellite positioning system in this invention shown in FIG. It is a graph which shows the difference of the phase distance in a normal state. It is a graph which shows the difference of the phase distance in the abnormal state where abnormality occurred in one frequency. It is a graph which shows the specific example of the abnormal data detection in another Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Satellite positioning system 20 Input device 30 Data processing device 31 Abnormal data detection part 32 Abnormal data removal part 40 Output device

Claims (12)

In a satellite positioning system that obtains position data using a two-frequency receiver that receives a signal transmitted from a satellite,
An anomaly data detector that detects an anomaly in one of the two frequencies received by the two-frequency receiver based on a difference in phase distance that is the product of the phase and wavelength;
A satellite positioning system comprising: an abnormal data removing unit that removes abnormal data detected by the abnormal data detecting unit. In a satellite positioning system that obtains position data using a two-frequency receiver that receives a signal transmitted from a satellite,
An input device for reading data from the two-frequency receiver;
A data processing device for processing data output from the input device;
An output device for displaying and storing the output of the data processing device,
The data processing device removes abnormal data detected by the abnormal data detection unit and abnormal data detected by the abnormal data detection unit that detects abnormal data from the phase and pseudorange of each of the two frequencies input from the input device and outputs the data An abnormal data output unit that outputs the pseudorange and phase of the two frequencies to the device;
A satellite positioning system that outputs pseudorange and phase data from the abnormal data removing unit of the data processing device to the output device.   The satellite positioning system according to claim 1 or 2, wherein detection of abnormal data by the abnormal data detection unit is performed based on an index obtained by a calculation formula.   The satellite positioning system according to claim 1, wherein the abnormal data detection unit sequentially receives data from the two-frequency receiver.   3. The satellite positioning system according to claim 1, wherein the abnormal data detection unit collectively receives RINEX format files recorded on a recording medium. In a satellite positioning method for obtaining position data using a two-frequency receiver that receives a signal transmitted from a satellite,
A data abnormality detection step of detecting a data abnormality of one of the two frequencies based on a difference in phase distance between two frequency signals received by the two-frequency receiver;
A satellite positioning method comprising: a data process including an abnormal data removal step of removing and outputting abnormal data detected in the data abnormality detection step.   The abnormal data detection step of the data processing includes a step of reading the phase distance and phase of the two frequencies, and a step of calculating an index based on the difference between the phase distance of one of the two frequencies and the phase distance of the other frequency The satellite positioning method according to claim 6, further comprising:   The calculation of the index for detecting the abnormal data uses a total value of the phase distance differences of normal data of a predetermined fixed number of epochs from the start of the data processing to the previous time. The satellite positioning method according to claim 7.   The satellite positioning method according to claim 7, wherein an estimated value by an interpolation function of a predetermined constant epoch number is used for calculation of the index for detecting abnormal data.   8. The calculation of an index for detecting abnormal data includes obtaining a difference between a pseudo distance and a phase distance of one of the two frequencies and a difference between a pseudo distance and a phase distance of the other frequency. Satellite positioning method described in 1.   A program enabling a computer to execute the steps of the satellite positioning method according to any one of claims 6 to 10.   A storage medium in which the computer program according to claim 11 is stored so as to be readable by a computer.

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