JP2017129555A - Positioning error correcting method, and device for the same, for use in satellite navigation systems - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce positioning errors in DGPS correcting systems arising from ionosphere delays and thereby enhance the precision of positioning.SOLUTION: A user station figures out its approximate position without using DGPS correction information or WADGPS correction information, uses DGPS correction information to perform first correction processing on measured data of positioning signals received from navigation satellites, uses WADGPS correction information to calculate a correction value in the station's own approximate position and in a DGPS correction station's position, performs second correction processing on the measured data having undergone the first correction processing with a value obtained by subtracting a correction value in the DGPS correction station's position from the correction value in the user station, and performs position measurement by using the measured data having undergone the first correction processing and the second correction processing thereby to calculate its own detailed position.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a positioning error correction method and apparatus in a satellite navigation system, and more particularly, to a positioning error correction method and apparatus in a differential correction method (DGPS).

  In general, electromagnetic waves (hereinafter referred to as signals) emitted from artificial satellites and celestial bodies pass through the ionosphere and troposphere before reaching the ground, but there is a delay when signals pass through the respective regions. . These delays are called ionospheric delay and tropospheric delay, respectively. Therefore, when this signal is used as a positioning signal, both the ionospheric delay and the tropospheric delay are positioning error sources.

  The navigation satellites constituting the satellite navigation system transmit positioning signals, and the user station that is a receiver of the user uses this to measure the distance between the navigation satellite and itself. In addition, a navigation message is superimposed on the positioning signal. By decoding the navigation message, it is possible to know the orbit information of the navigation satellite and the clock error included in the positioning signal. However, these include errors, and become a positioning error source when the user receiver determines the position.

  As a method for reducing these positioning errors, there is DGPS that provides correction information corresponding to the positioning error to the user station and performs a correction process on the user station side to reduce the positioning error. An actual example of a DGPS system using the DGPS method is a medium wave beacon DGPS operated by the Japan Coast Guard. This DGPS system broadcasts DGPS correction data superimposed on an existing medium wave beacon mainly for sailing vessels. Note that this broadcast data is in the RTCM SC104 format, and the ITU-R M.264 format. It is standardized as 823-1.

  The DGPS method is characterized in that it provides correction information for correcting collectively to the user station without particularly distinguishing error factors such as the satellite clock, satellite orbit, ionospheric delay, and tropospheric delay. Hereinafter, a DGPS system using the DGPS method will be described with reference to FIG.

  As shown in FIG. 2, the DGPS correction station 106 is installed at a known point whose position is known for the purpose of improving the positioning accuracy by the positioning signals from the navigation satellites 102 (102a, 102b...). Reference numeral 105 denotes a user station that is a receiver of the user.

  The navigation satellites 102 (102a, 102b...) Are GPS satellites that transmit positioning signals, and detailed orbit information of the navigation satellite itself is superimposed on the positioning signals. When the positioning signal passes through the ionosphere 108, a delay occurs, which becomes an error factor called ionosphere delay.

  The DGPS correction station 106 has a function of creating correction information from the received measurement data of the positioning signal from the navigation satellite and the known position information of itself, and the created correction information via the communication line 107 to the user station 105. It has a function to transmit to. The error factors of the satellite navigation system include satellite clock, satellite orbit, ionosphere delay, and troposphere delay, but these are not particularly distinguished in the DGPS correction station 106, and correction information for correcting collectively is created. The

  The communication line 107 can have any configuration, but is usually wireless and can use a geostationary satellite. In the medium wave beacon DGPS, a medium wave radio signal is used as the communication line 107.

  The user station 105 has a GPS receiver capable of receiving a positioning signal having the same frequency as that received by the DGPS correction station among the positioning signals transmitted from the navigation satellites. It has a function that can improve the positioning accuracy by applying the correction information from. As described above, the error factors of the satellite navigation system include the satellite clock, the satellite orbit, the ionosphere delay, and the troposphere delay, but the user station 105 corrects them collectively without distinguishing them.

  However, the density and thickness of the actual ionosphere differ depending on the location, and depending on the position of the user station, the ionosphere delay 109b differs from the ionosphere delay 109a in the DGPS correction station. This is an error factor in DGPS, and this error factor becomes more noticeable as the user station moves away from the DGPS correction station.

  On the other hand, wide-area differential correction (Wide Area Differential GPS) that performs effective correction over a wide geographical range by individually correcting error factors in positioning such as satellite clock, satellite orbit, ionospheric delay, and tropospheric delay. : Hereinafter referred to as WADGPS). In the WADGPS method, the reason for individually correcting the error factors is that the satellite clock is affected regardless of the location of the user station, but the satellite orbit, ionospheric delay, and tropospheric delay are present. This is because the influence varies depending on the position. Therefore, these positioning error sources are separated and individually corrected, and the satellite orbit, ionospheric delay, and tropospheric delay are set to appropriate correction amounts depending on the location of the user station, thereby providing a wide geographical range. It is possible to perform wide-area differential correction effective in. As an example of the WADGPS system using the WADGPS method, there is a satellite-based satellite navigation reinforcement system (hereinafter referred to as SBAS) that is being put into practical use worldwide.

  Conventionally, as a WADGPS system that performs such wide-area differential correction, as described in Patent Document 1 and Patent Document 2, there is a satellite navigation system shown in FIGS. This will be described below.

  3 and 4, 151 (151a, 151b...) Is a monitor station, and the position is known for the purpose of improving the positioning accuracy from the positioning signals from the navigation satellites 152 (152a, 152b...). A plurality of locations are installed at certain known points. The monitor station 151 (151a, 151b...) Has a network 153, and is connected to the master station 154 via the network 153. Reference numeral 155 denotes a user station that is a receiver of the user.

  The navigation satellites 152 (152a, 152b...) Are GPS satellites, and each transmits detailed orbit information of the navigation satellite itself at two frequencies (L1: 1.6 GHz band / L2: 1.2 GHz band). ing. Since the ionospheric delay has a characteristic that it varies depending on the frequency of the signal, the ionospheric delay can be obtained by calculation using the measurement data of the two frequencies received at the monitor station.

  The monitor station 151 (151a, 151b...) Has a two-frequency GPS receiver capable of receiving positioning signals transmitted from navigation satellites at two frequencies (L1, L2), and the received measurement. Data is transmitted to the master station 154 via the network 153.

  The master station 154 has a function of obtaining an ionospheric delay amount from measurement data of a positioning signal received from the navigation satellite received by the monitor station, and an IGP (Ionospheric Grid) set every 5 degrees in longitude and latitude using this ionospheric delay amount. (Point: ionosphere grid point, hereinafter referred to as IGP) is used to calculate the ionospheric delay, and to create the grid information that is the correction information, to create the correction information of the orbit of the navigation satellite, and to be transmitted from the navigation satellite And a function of transmitting the generated correction information (grid information, trajectory correction information, clock correction information) to the user station 155.

  The user station 155 normally has a single-frequency GPS receiver that can receive a positioning signal transmitted from a navigation satellite for only one frequency (L1), and corrects it using correction information from the master station 154. By doing so, it has a function that can improve positioning accuracy.

  3 and 4, the monitor station 151 (151a, 151b...) Is a positioning signal transmitted from the navigation satellite 152 (152a, 152b...), A quasi-zenith satellite, or a geostationary satellite (not shown). The measurement data is transmitted to the master station 154 via the network 153.

  The master station 154 calculates an ionospheric delay amount, which is a propagation delay due to the ionosphere, based on the measurement data of the two-frequency GPS receiver included in each monitor station 151 (151a, 151b...) (FIGS. 3161 and 4171). ). Since the ionospheric delay amount calculated in the master station 154 is calculated using the measurement data of the two-frequency GPS receiver, the measurement error is small and the accuracy is high. Next, the master station 154 uses this ionospheric delay amount to calculate model parameters based on the ionosphere model, thereby obtaining ionospheric delay amounts in each IGP, and creates grid information as correction information thereof (FIG. 3). 162). This grid information is coarsened to be transmitted to the user station 155, and is created for each IGP.

  Next, the master station 154 creates navigation satellite orbit correction information using the ionospheric delay amount (FIG. 3163), and further creates positioning signal clock correction information transmitted from the navigation satellite (FIG. 3163). FIG. 3 164).

  The master station 154 transmits the correction information (grid information, orbit correction information, clock correction information) thus created to the user station 155 via the geostationary satellite (FIG. 3165).

  The user station 155 receives the correction information (grid information, orbit correction information, clock correction information) transmitted from the master station 154 and performs correction processing (FIG. 3166). That is, the correction information is used to correct the ionospheric propagation delay in the user station 155, the orbit of the navigation satellite, and the clock of the positioning signal from the navigation satellite.

  Regarding the correction of the ionospheric propagation delay, the grid information transmitted from the master station 154 is linearly interpolated using the grid information of four IGPs adjacent to the point where the positioning signal passes through the ionosphere. The ionospheric delay amount is obtained and corrected (FIG. 4 172). In this way, the user station 155 corrects the ionospheric propagation delay, the satellite orbit, the satellite clock, and performs positioning of the user station 155.

JP 2007-171082 A JP 2011-203100 A

  Both the DGPS system and the WADGPS system are satellite navigation system systems for obtaining the position of the user station as accurately as possible. However, the positioning error due to the four error factors (satellite clock, satellite orbit, ionospheric delay, and tropospheric delay) cannot be completely corrected, and further reduction of the positioning error has been an important issue.

  In particular, the ionospheric propagation delay is the largest source of error in satellite navigation systems. In the ionosphere (D, E, and F layers) existing in the upper atmosphere, disturbance phenomena of various scales occur temporally and spatially, greatly affecting the radio waves of satellite communications. Since the ultraviolet rays and X-rays from the sun received by the atmosphere change according to the season, latitude / longitude, time, solar activity cycle, etc., the ionosphere basically changes depending on these. In addition to these steady changes, the ionosphere has an increase in X-rays and high-energy particles due to sudden solar explosions, disturbances such as magnetic storms typified by aurora activity, or the neutral atmosphere that forms the host. It changes complicatedly under the influence of disturbance. And sometimes it becomes a disturbance state called ionospheric storm.

  In the WADGPS method, individual correction information is created for the ionospheric delay, and an appropriate correction amount is applied according to the position of the user station, so that appropriate correction can be performed over a wide geographical range. On the other hand, in the DGPS system, when the user station is in the vicinity of the DGPS correction station, the positioning error in both stations is approximately equal, so that better correction can be expected than in the WADGPS system. Since this is not a correction method for each factor, there is a problem that positioning accuracy increases as the user station moves away from the DGPS correction station.

  As a countermeasure against ionospheric delay, it is conceivable that the user station performs positioning using a two-frequency receiver as in the WADGPS monitor station. However, if a two-frequency GPS receiver similar to the monitor station is used as the GPS receiver of the user station, the size of the antenna increases, and in addition, two sets of high-frequency circuits are required, which increases costs. There was a problem. In addition, since a plurality of measurement data is used, there is a problem that noise increases. Furthermore, there is a problem that only a single-frequency GPS can be used for a receiver mounted on an aircraft.

  According to the first aspect of the present invention, DGPS correction information for receiving a positioning signal from a navigation satellite and correcting errors contained in the positioning signal collectively at a DGPS correction station installed at a known point is provided. A DGPS system that creates and transmits the created DGPS correction information to a user station that is a receiver that the user has via a first communication line, and a plurality of monitor stations installed at known points, from a navigation satellite The positioning signal is received, and the master station obtains the correction information of the positioning signal clock, the correction information of the orbit of the navigation satellite, the correction information of the ionosphere delay, and the correction information of the troposphere delay, and obtains these correction information. A satellite comprising a WADGPS system that creates summarized WADGPS correction information and transmits the created WADGPS correction information to the user station via the second communication line. In the legal system, the user station obtains the approximate position of the own station without using the correction information, and the user station uses the DGPS correction information to calculate the measurement data of the received positioning signal from the navigation satellite. 1, the user station uses the WADGPS correction information to calculate the correction value at the approximate position of the own station and the correction value at the position of the DGPS correction station, and the user station calculates the approximate position of the own station. The second correction process is performed on the measurement data that has been subjected to the first correction process by using a value obtained by subtracting the correction value at the position of the DGPS correction station from the correction value at the user station. This is a method for correcting a positioning error in a satellite navigation system, wherein positioning is performed using measurement data subjected to correction processing and second correction processing.

  The invention according to claim 2 is the invention according to claim 1, wherein the first communication line is the same as the second communication line.

  The invention according to claim 3 is the invention according to any one of claims 1 to 2, wherein the function of the DGPS correction station is provided by combining the master station and the monitor station.

  In the invention according to claim 4, DGPS correction information for receiving a positioning signal from a navigation satellite at a DGPS correction station installed at a known point and correcting errors contained in the positioning signal collectively. A DGPS system that creates and transmits the created DGPS correction information to a user station that is a receiver that the user has via a first communication line, and a plurality of monitor stations installed at known points, from a navigation satellite The positioning signal is received, and the master station obtains the correction information of the positioning signal clock, the correction information of the orbit of the navigation satellite, the correction information of the ionosphere delay, and the correction information of the troposphere delay, and obtains these correction information. A satellite comprising a WADGPS system that creates summarized WADGPS correction information and transmits the created WADGPS correction information to the user station via the second communication line. In the legal system, the first correction is performed on the measurement data of the received positioning signal from the navigation satellite using the function of obtaining the approximate position of the own station without using the DGPS correction information and the WADGPS correction information, and the DGPS correction information. A function for performing processing, a function for calculating a correction value at the approximate position of the own station and a correction value at the position of the DGPS correction station using the WADGPS correction information, and a DGPS correction from the correction value at the approximate position of the own station A function of performing a second correction process on the measurement data subjected to the first correction process based on a value obtained by subtracting the correction value at the station position, a first correction process, and a second correction process. It is an apparatus for correcting a positioning error in a satellite navigation system, characterized by comprising a user station having a function of performing positioning using performed measurement data.

  The invention according to claim 5 is the invention according to claim 4, wherein the first communication line is the same as the second communication line.

  The invention according to claim 6 is the invention according to any one of claims 4 to 5, wherein the master station and the monitor station are combined to have the function of the DGPS correction station.

  According to the seventh aspect of the present invention, DGPS correction information for receiving a positioning signal from a navigation satellite and correcting errors contained in the positioning signal collectively at a DGPS correction station installed at a known point is provided. A DGPS system that creates and transmits the created DGPS correction information to a user station that is a receiver that the user has via a first communication line, and a plurality of monitor stations installed at known points, from a navigation satellite The system comprises a system that receives positioning signals, creates ionospheric delay correction information in the master station, and transmits the created ionospheric delay correction information to the user station via the second communication line to correct the ionospheric delay. In the satellite navigation system, the user station obtains the approximate position of the user station without using the correction information, and the user station uses the DGPS correction information to receive the received navigation satellite. The first correction processing is performed on the measurement data of the positioning signals, and the user station uses the ionospheric delay correction information to calculate the correction value at the approximate position of the own station, the correction value at the position of the DGPS correction station, and The user station calculates a second value for the measurement data subjected to the first correction process using a value obtained by subtracting the correction value at the position of the DGPS correction station from the correction value at the approximate position of the own station. This is a method for correcting a positioning error in a satellite navigation system, wherein the user station performs positioning using the measurement data subjected to the first correction processing and the second correction processing.

  The invention according to claim 8 is the invention according to claim 7, wherein the system for correcting the ionospheric delay is a WADGPS system.

  The invention according to claim 9 is the invention according to any one of claims 7 to 8, wherein the first communication line is the same as the second communication line.

  The invention according to claim 10 is the invention according to any one of claims 7 to 9, wherein the master station and the monitor station are combined to have the function of the DGPS correction station.

  In the invention according to claim 11, DGPS correction information for receiving a positioning signal from a navigation satellite at a DGPS correction station installed at a known point and correcting errors contained in the positioning signal collectively. A DGPS system that creates and transmits the created DGPS correction information to a user station that is a receiver that the user has via a first communication line, and a plurality of monitor stations installed at known points, from a navigation satellite The system comprises a system that receives positioning signals, creates ionospheric delay correction information in the master station, and transmits the created ionospheric delay correction information to the user station via the second communication line to correct the ionospheric delay. In the satellite navigation system, received using the DGPS correction information and the function for obtaining the approximate position of the local station without using the DGPS correction information and the ionospheric delay correction information. Using the function of performing the first correction process on the measurement signal of the positioning signal from the law satellite and the correction information of the ionospheric delay, the correction value at the approximate position of the own station, the correction value at the position of the DGPS correction station, And a correction value obtained by subtracting the correction value at the position of the DGPS correction station from the correction value at the approximate position of the own station, and a second correction for the measurement data subjected to the first correction processing. A positioning error in a satellite navigation system, comprising a user station having a function for performing processing and a function for performing positioning using measurement data subjected to the first correction processing and the second correction processing, is corrected. Device.

  The invention according to claim 12 is the invention according to claim 11, wherein the system for correcting the ionospheric delay is a WADGPS system.

  The invention according to claim 13 is the invention according to any one of claims 11 to 12, wherein the first communication line is the same as the second communication line.

  The invention according to claim 14 is the invention according to any one of claims 11 to 13, wherein the function of the DGPS correction station is also provided by a combination of the master station and the monitor station.

  Since the invention according to claim 1, claim 4, claim 7 and claim 11 is configured as described above, since the fluctuation of the ionosphere is large, the conventional methods of DGPS and WADGPS are both local. Even if both the positioning error and the error due to the ionospheric delay cannot be corrected sufficiently, even if a sufficient positioning accuracy cannot be obtained, the first correction process using the DGPS correction information causes a local error. Since the error due to the ionospheric delay can be corrected by the second correction process using the WADGPS correction information after correcting the positioning error, both errors are sufficiently corrected to reduce the positioning error and improve the positioning accuracy. It is possible.

  Since the inventions according to claims 2, 5, 9, and 13 are configured as described above, they are the same as the inventions according to claims 1, 4, 7, and 11, respectively. There is an effect. In addition, since the functions of the first communication line and the second communication line can be realized by a single communication line, the number of communication lines can be reduced and the cost can be reduced.

  Since the inventions according to claims 3, 6, 10, and 14 are configured as described above, they are the same as the inventions according to claims 1, 4, 7, and 11, respectively. There is an effect. In addition, since the function of the DGPS correction station can be realized by a combination of the existing master station and the monitor station, the total number of stations can be reduced and the cost can be reduced.

  Since the inventions according to claims 8 and 12 are configured as described above, they have the same effects as the inventions according to claim 1, claim 4, claim 7, and claim 11, respectively.

The Example of this invention is shown and it is a schematic diagram for demonstrating the positioning method in the satellite navigation system of this invention. It is a schematic diagram for demonstrating a DGPS system among the positioning methods in the conventional satellite navigation system. It is a schematic diagram for demonstrating a WADGPS system among the positioning methods in the conventional satellite navigation system. It is a schematic diagram for demonstrating a WADGPS system among the positioning methods in the conventional satellite navigation system.

  A DGPS correction station installed at a known point receives a positioning signal from a navigation satellite, creates DGPS correction information for collectively correcting errors included in the positioning signal, and creates this DGPS correction. A DGPS system that transmits information to a user station, which is a receiver that the user has via a first communication line, and a plurality of monitor stations installed at known points, receive positioning signals from navigation satellites, and a master station In this, the positioning signal clock correction information, navigation satellite orbit correction information, ionospheric delay correction information, and tropospheric delay correction information are obtained, and the WADGPS correction information is created by combining these correction information. In the satellite navigation system including the WADGPS system that transmits the created WADGPS correction information to the user station via the second communication line, The user station obtains the approximate position of the own station without using the correction information, and the user station uses the DGPS correction information to perform a first correction on the received measurement data of the positioning signal from the navigation satellite. The user station uses the WADGPS correction information to calculate the correction value at the approximate position of the own station and the correction value at the position of the DGPS correction station, and the user station corrects the correction value at the approximate position of the own station. From the value obtained by subtracting the correction value at the position of the DGPS correction station, the second correction process is performed on the measurement data subjected to the first correction process, and the user station performs the first correction process and Positioning is performed using the measurement data subjected to the second correction process, and the detailed position of the own station is calculated.

An embodiment of the present invention will be described in detail with reference to FIG.
FIG. 1 shows an embodiment of the present invention and is a schematic diagram for explaining a positioning method in the satellite navigation system of the present invention.

  In this embodiment, since the variation of the ionosphere is large, both of the conventional method DGPS and WADGPS cannot sufficiently correct both the local positioning error and the error due to the ionospheric delay. An embodiment in the case where accurate positioning accuracy cannot be obtained is shown, and both DGPS correction information and WADGPS correction information are provided to the user station. In the user station, the local positioning error can be corrected by the first correction process using the DGPS correction information, and the error due to the ionospheric delay can be corrected by the second correction process using the WADGPS correction information. The purpose is to reduce the positioning error by sufficiently correcting the error and improve the positioning accuracy.

  As shown in FIG. 1, 1 (1a, 1b...) Is a monitor station, and the position is known for the purpose of improving the positioning accuracy by the positioning signal from the navigation satellite 2 (2a, 2b...). It is installed at several known points. The monitor station 1 (1a, 1b...) Has a network 3 and is connected to the master station 4 via the network 3. Reference numeral 5 denotes a user station, which is a receiver that the user has. 6 is a DGPS correction station, and its position is known for the purpose of improving the positioning accuracy by the positioning signal from the navigation satellite 2 (2a, 2b...), Like the monitor station 1 (1a, 1b...). It is installed at a known point. Reference numeral 7 denotes a communication line. The first communication line 7 a for transmitting the DGPS correction information created by the DGPS correction station 6 to the user station 5 and the WADGPS correction information created by the master station 4 are transmitted to the user station 5. And a second communication line 7b. 9 is the ionospheric delay of the ionosphere 8, 9 a is the ionospheric delay of the DGPS correction station 6, and 9 b is the ionospheric delay of the user station 5.

  Navigation satellite 2 (2a, 2b...) Is a GPS satellite, and each transmits a positioning signal at two frequencies (L1: 1.6 GHz band / L2: 1.2 GHz band). Detailed orbit information of the navigation satellite itself is superimposed. The positioning signal transmitted from the navigation satellite 2 (2a, 2b...) Generates a delay when passing through the ionosphere 8, and this becomes an error factor called ionosphere delay.

  The DGPS correction station 6 has a function for creating DGPS correction information from the received measurement data of the positioning signal from the navigation satellite and the position information of the known DGPS correction station 6 itself, and the created DGPS correction information is the first DGPS correction information. It has a function of transmitting to the user station 5 via the communication line 7a. The DGPS correction information created by the DGPS correction station 6 is correction information for correcting the satellite clock, satellite orbit, ionospheric delay, and tropospheric delay, which are error factors of the satellite navigation system, without any distinction. A DGPS correction station 6 that receives a positioning signal from the navigation satellite 2 (2a, 2b,...) And creates DGPS correction information for collectively correcting errors in the positioning signal, and the DGPS correction information. The DGPS system is configured by the first communication line 7 a for transmitting the message to the user station 5.

  The monitor station 1 (1a, 1b...) Is a two-frequency type capable of receiving positioning signals transmitted at two frequencies (L1, L2) from the navigation satellite 2 (2a, 2b...). A GPS receiver is included, and the received measurement data is transmitted to the master station 4 via the network 3. The ionospheric delay has a characteristic that it varies depending on the frequency of the signal. Therefore, the ionospheric delay can be obtained by calculation using the measurement data of the two frequencies received at the monitor station 1 (1a, 1b...).

  The master station 4 uses the ionospheric delay from the measurement data of the positioning signal received from the navigation satellite 2 (2a, 2b...) Received by the monitor station and uses this ionospheric delay every 5 degrees in latitude and longitude. A function of calculating ionospheric delay amount in a set IGP (Ionospheric Grid Point, hereinafter referred to as IGP), and creating grid information as correction information thereof, and a navigation satellite 2 (2a, 2b... ) A function for creating correction information of a clock of a positioning signal transmitted from), a function for creating correction information for the orbit of navigation satellite 2 (2a, 2b...), A function for obtaining correction information for tropospheric delay, The correction information including at least the generated correction information (grid information, satellite clock correction information, satellite orbit correction information, tropospheric delay correction information) The DGPS correction information has at least a function of transmitting to the user station 5 via the second communication line 7b. Note that the monitor station 1 (1a, 1b...), The monitor station 1 (1a, 1b...) That receives the positioning signal from the navigation satellite 2 (2a, 2b. The network 3 constructed in between, the master station 4 for creating WADGPS correction information for individually correcting the error factors of the positioning signals from the navigation satellites 2 (2a, 2b...), And the WADGPS correction The WADGPS system is configured by the second communication line 7 b for transmitting information to the user station 5.

  The user station 5 has a GPS receiver capable of receiving one of the positioning signals transmitted from the navigation satellite 2 (2a, 2b...), And is connected via the first communication line 7a. A function for receiving DGPS correction information from the DGPS correction station 6, a function for receiving WADGPS correction information from the master station 4 via the second communication line 7b, and positioning using a positioning signal from a navigation satellite cannot be performed. Also has a function of calculating the approximate position of the local station. In addition, the user station 5 includes a function for performing first correction processing on the positioning data of the positioning signal from the navigation satellite 2 (2a, 2b...) Received using the DGPS correction information, and the WADGPS correction information. Based on the function of calculating an appropriate correction value according to the approximate position of the own station, that is, using the WADGPS correction information, the correction value 5A at the approximate position of the own station and the correction value 6A at the position of the DGPS correction station 6 And a value (5A-6A) obtained by subtracting the correction value 6A at the position of the DGPS correction station 6 from the correction value 5A at the approximate position of the own station. It has a function of performing a second correction process on the measurement data performed, and a function of performing positioning using the measurement data subjected to the first correction process and the second correction process.

  Next, the operation will be described with reference to FIG.

  The DGPS correction station 6 uses the measurement data of the positioning signal received from the navigation satellite 2 (2a, 2b...) And the known position information of itself, the satellite clock, the satellite orbit, which are the error factors of the satellite navigation system, Correction information for correcting the ionospheric delay and tropospheric delay in a lump without making a particular distinction is created, and the created correction information is transmitted as DGPS correction information to the user station 5 via the first communication line 7a.

  On the other hand, the monitor station 1 (1a, 1b...) Receives the measurement data received from the navigation satellite 2 (2a, 2b...) At two frequencies (L1, L2) and transmits the measurement data to the network. 3 to the master station 7.

  The master station 4 obtains the ionospheric delay from the measurement data of the positioning signal from the navigation satellite 2 (2a, 2b...) Received by the monitor station 1 (1a, 1b...), And uses this ionospheric delay. The amount of ionospheric delay in the IGP set every 5 degrees in longitude and latitude is obtained, and grid information as correction information is created. Further, the master station 4 corrects the correction information of the clock of the positioning signal transmitted from the navigation satellite 2 (2a, 2b...), The correction information of the orbit of the navigation satellite 2 (2a, 2b...), And the troposphere. The delay correction information is created, and the created correction information (grid information, satellite clock correction information, satellite orbit correction information, tropospheric delay correction information) is sent as WADGPS correction information via the second communication line 7b. Transmit to user station 5.

  First, the user station 5 receives the positioning signal transmitted from the navigation satellite 2 (2a, 2b...), Calculates the approximate position of the own station without using the DGPS correction information and the WADGPS correction information, The DGPS correction information from the DGPS correction station 6 is received via the first communication line 7a, and the WADGPS correction information from the master station 4 is received via the second communication line 7b.

  Next, the user station 5 uses the DGPS correction information from the DGPS correction station 6 to perform a first correction process on the measurement data received from the positioning signal from the navigation satellite. By performing the first correction process using the DGPS correction information, the satellite clock, satellite orbit, ionosphere delay, and troposphere delay, which are the error factors of the satellite navigation system, can be corrected together without being distinguished. , Local positioning error can be corrected. However, as described above, the ionosphere 8 varies in density and thickness depending on the location. As shown in FIG. 1, the ionosphere delay 9a at the position of the DGPS correction station 6 and the ionosphere delay 9b at the position of the user station 5 Is different. Therefore, the error (9a-9b) due to the ionospheric delay cannot be removed only by the first correction process performed using the DGPS correction information created by the ionospheric delay 9a at the position of the DGPS correction station 6.

  In order to remove an error (9a-9b) due to the ionospheric delay 9a at the position of the DGPS correction station 6 and the ionospheric delay 9b at the position of the user station 5, a second correction process is performed. First, the user station 5 calculates the correction value (5A) at the approximate position of the own station using the WADGPS correction information from the master station 4, and further, the correction value at the position of the DGPS correction station 6 using the WADGPS correction information. (6A) is calculated. As described above, the WADGPS correction information is correction information that can individually correct error factors during positioning such as satellite clock, satellite orbit, ionosphere delay, and tropospheric delay. It is possible to calculate a correction value for removing an ionospheric delay error. Using the value obtained by subtracting the correction value (6A) at the DGPS correction station 6 from the correction value (5A) at the approximate position of the own station, the second correction is performed on the measurement data subjected to the first correction processing. Perform correction processing.

  The user station 5 calculates the position of the own station in detail using measurement data to which both the first correction process and the second correction process are applied. Thus, the local positioning error can be corrected by the first correction process using the DGPS correction information, and the error due to the ionospheric delay can be corrected by the second correction process using the WADGPS correction information. It is possible to sufficiently correct the error to reduce the positioning error and improve the positioning accuracy.

  In this embodiment, the DGPS correction station 6, the master station 4, and the monitor station 1 (1a, 1b...) Are handled separately, but these are configured using the same hardware as appropriate. Also good. That is, the DGPS correction station 6 has a GPS receiver and a function of creating DGPS correction information. However, the DGPS correction station 6 uses the measurement data received by the monitor station 1 (1a, 1b. The correction information may be created, and the function of the DGPS correction station 6 may be realized by a combination of the master station 4 and the monitor station 1 (1a, 1b...). In this case, the monitor station 1 (1a, 1b...) Will be used in creating both DGPS correction information and WADGPS correction information.

In this embodiment, the DGPS correction information and the WADGPS correction information are configured to be transmitted through separate communication lines. However, they may be configured to be transmitted through a single communication line. Although a specific communication line is arbitrary, in addition to satellite communication such as a geostationary satellite or a quasi-zenith satellite, the Internet or a wireless LAN may be used.
In this embodiment, the satellite navigation system includes a WADGPS system and a DGPS system, but is not limited to this. As long as the ionospheric delay can be corrected with higher accuracy than the DGPS system, the satellite navigation system may be configured by combining the ionospheric delay correcting system and the DGPS system.

The positioning method and apparatus in the satellite navigation system according to the present invention can be used for a mobile positioning system, a guidance system, and the like. Since the positioning accuracy of the user station is improved, the utilization rate of the navigation mode with vertical guidance can be improved. The spread of SBAS can be expected by improving the utilization rate of the navigation mode with vertical guidance. It can also be applied to the quasi-zenith satellite system being developed by the Japan Aerospace Exploration Agency.
In particular, in the quasi-zenith satellite submeter-class positioning correction service, a configuration based only on the DGPS method is currently considered, but further improvement in performance can be achieved by using the present invention.

1 (1a, 1b ...) Monitor station 2 (2a, 2b ...) Navigation satellite 3 Network 4 Master station 5 User station 6 DGPS correction station 7 (7a, 7b) Communication line (first communication line, first communication line) 2 communication lines)

Claims (14)

A DGPS correction station installed at a known point receives a positioning signal from a navigation satellite, creates DGPS correction information for collectively correcting errors included in the positioning signal, and creates this DGPS correction. A DGPS system that transmits information to a user station that is a receiver that the user has via a first communication line;
A plurality of monitor stations installed at known points receive positioning signals from the navigation satellites, and a master station receives correction information of clocks of the positioning signals, correction information of orbits of the navigation satellites, and ionospheric delays. A WADGPS system that obtains correction information and tropospheric delay correction information, creates WADGPS correction information that summarizes the correction information, and transmits the created WADGPS correction information to the user station via a second communication line In a satellite navigation system consisting of
The user station obtains the approximate position of its own station without using these correction information,
The user station performs a first correction process on the measurement data of the positioning signal from the received navigation satellite using the DGPS correction information,
The user station uses the WADGPS correction information to calculate a correction value at the approximate position of the local station and a correction value at the position of the DGPS correction station,
The user station uses a value obtained by subtracting the correction value at the position of the DGPS correction station from the correction value at the approximate position of the own station, and then performs second measurement on the measurement data subjected to the first correction processing. Correction process,
The method of correcting a positioning error in a satellite navigation system, wherein the user station performs positioning using measurement data subjected to the first correction processing and the second correction processing. The method for correcting a positioning error in a satellite navigation system according to claim 1, wherein the first communication line is the same as the second communication line. The method for correcting a positioning error in the satellite navigation system according to claim 1, wherein the function of the DGPS correction station is provided by a combination of the master station and the monitor station. A DGPS correction station installed at a known point receives a positioning signal from a navigation satellite, creates DGPS correction information for collectively correcting errors included in the positioning signal, and creates this DGPS correction. A DGPS system that transmits information to a user station that is a receiver that the user has via a first communication line;
A plurality of monitor stations installed at known points receive positioning signals from the navigation satellites, and a master station receives correction information of clocks of the positioning signals, correction information of orbits of the navigation satellites, and ionospheric delays. A WADGPS system that obtains correction information and tropospheric delay correction information, creates WADGPS correction information that summarizes the correction information, and transmits the created WADGPS correction information to the user station via a second communication line In a satellite navigation system consisting of
A function for obtaining the approximate position of the local station without using the DGPS correction information and the WADGPS correction information;
A function of performing a first correction process on the measurement data of the positioning signal from the received navigation satellite using the DGPS correction information;
A function of calculating a correction value at the approximate position of the local station and a correction value at the position of the DGPS correction station using the WADGPS correction information;
A second correction process is performed on the measurement data subjected to the first correction process by a value obtained by subtracting the correction value at the position of the DGPS correction station from the correction value at the approximate position of the own station. Function and
An apparatus for correcting a positioning error in a satellite navigation system, comprising: a user station having a function of performing positioning using measurement data subjected to the first correction process and the second correction process. The apparatus for correcting a positioning error in a satellite navigation system according to claim 4, wherein the first communication line is the same as the second communication line. The apparatus for correcting a positioning error in the satellite navigation system according to any one of claims 4 to 5, wherein a function of the DGPS correction station is provided by a combination of the master station and the monitor station. A DGPS correction station installed at a known point receives a positioning signal from a navigation satellite, creates DGPS correction information for collectively correcting errors included in the positioning signal, and creates this DGPS correction. A DGPS system that transmits information to a user station that is a receiver that the user has via a first communication line;
A plurality of monitor stations installed at known points receive positioning signals from the navigation satellites, the master station creates ionospheric delay correction information, and the created ionospheric delay correction information is used as the second communication line. In a satellite navigation system consisting of a system for correcting ionospheric delay transmitted to the user station via
The user station obtains the approximate position of its own station without using these correction information,
The user station performs a first correction process on the measurement data of the positioning signal from the received navigation satellite using the DGPS correction information,
The user station uses the ionospheric delay correction information to calculate a correction value at the approximate position of the own station and a correction value at the position of the DGPS correction station,
The user station uses a value obtained by subtracting the correction value at the position of the DGPS correction station from the correction value at the approximate position of the own station, and then performs second measurement on the measurement data subjected to the first correction processing. Correction process,
The method of correcting a positioning error in a satellite navigation system, wherein the user station performs positioning using measurement data subjected to the first correction processing and the second correction processing. The method for correcting a positioning error in a satellite navigation system according to claim 7, wherein the system for correcting the ionospheric delay is a WADGPS system. The method for correcting a positioning error in a satellite navigation system according to any one of claims 7 to 8, wherein the first communication line is the same as the second communication line. The method for correcting a positioning error in the satellite navigation system according to any one of claims 7 to 9, wherein a function of the DGPS correction station is provided by a combination of the master station and the monitor station. A DGPS correction station installed at a known point receives a positioning signal from a navigation satellite, creates DGPS correction information for collectively correcting errors included in the positioning signal, and creates this DGPS correction. A DGPS system that transmits information to a user station that is a receiver that the user has via a first communication line;
A plurality of monitor stations installed at known points receive positioning signals from the navigation satellites, the master station creates ionospheric delay correction information, and the created ionospheric delay correction information is used as the second communication line. In a satellite navigation system consisting of a system for correcting ionospheric delay transmitted to the user station via
A function for obtaining an approximate position of the own station without using DGPS correction information and ionospheric delay correction information;
A function of performing a first correction process on the measurement data of the positioning signal from the received navigation satellite using the DGPS correction information;
Using the ionospheric delay correction information, a function of calculating a correction value at the approximate position of the own station and a correction value at the position of the DGPS correction station;
A second correction process is performed on the measurement data subjected to the first correction process by a value obtained by subtracting the correction value at the position of the DGPS correction station from the correction value at the approximate position of the own station. Function and
An apparatus for correcting a positioning error in a satellite navigation system, comprising: a user station having a function of performing positioning using measurement data subjected to the first correction process and the second correction process. The apparatus for correcting a positioning error in the satellite navigation system according to claim 11, wherein the system for correcting the ionospheric delay is a WADGPS system. The apparatus for correcting a positioning error in a satellite navigation system according to any one of claims 11 to 12, wherein the first communication line is the same as the second communication line. The apparatus for correcting a positioning error in the satellite navigation system according to any one of claims 11 to 13, wherein a function of the DGPS correction station is provided by a combination of the master station and the monitor station.

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