JP2010019728A - Positioning method and positioning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely specify a position. <P>SOLUTION: A base station distributes a corrected value computed based on the GPS signal received from a GPS satellite in association with the elevation angle value of the GPS satellite (S1-S3). A mobile station performs positioning by applying the corrected value close to the elevation angle computed value computed for the GPS satellite which the mobile station received based on the GPS signal which the mobile station received from the GPS satellite (T6-T9). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a positioning method and a positioning device for positioning a position with high accuracy using a correction value.

As this type of technology, for example, differential GPS (hereinafter referred to as DGPS) positioning technology can be cited. This DGPS positioning technique is one of positioning methods that improve the position identification accuracy by measuring the distance to the satellite at a reference station with a clear position and using the error between the measured distance and the true distance as a correction value. It is. Since the correction value changes with the passage of time, the latest correction value must always be used. Therefore, accuracy is gradually deteriorated unless communication is frequently performed and the latest correction value is used. Therefore, a positioning method (for example, see Patent Document 1) that maintains accuracy by predicting the current correction value from the latest past correction value has been studied. In addition, a positioning method using correction values at the same time in the past (for example, see Patent Document 2) has been studied.
JP 2004-069587 A JP-A-11-109018

  However, there is a problem with the method of predicting the correction value based on the time, and the correction value before the predetermined period in the past from the present time cannot be used. Moreover, if the correction value of the nearest reference point (reference station) is not used, the accuracy will be low, and if the reference station that communicates with the mobile station is changed due to movement of the mobile station, it is necessary to store the correction value again. Will occur. In this case, since it is not possible to obtain a correction value in an environment where communication with the reference station is not possible, it is difficult to specify the exact position.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a positioning method and a positioning apparatus that can perform position specification with high accuracy.

  According to the invention according to claim 1 or 5, the correction value or the correction value prediction formula calculated based on the first satellite information received by the reference station from the satellite is associated with the elevation angle value of the satellite, and the mobile station from the satellite Elevation angle calculation value obtained by calculating the elevation angle of the satellite received by the mobile station based on the position calculation information obtained by calculating the position of the mobile station based on the received second satellite information and the orbit information included in the second satellite information. Since the positioning is performed by applying the correction value or the correction value prediction formula associated with the elevation angle value according to the position, the position can be accurately identified.

  As in the invention according to claim 2 or 6, positioning is performed by applying a correction value associated with an elevation angle value under a condition in which a satellite from which a reference station has received satellite information and a satellite from which a mobile station has received satellite information match. Good.

  According to the invention according to claim 3 or 7, even if the error of the correction value becomes large at a high elevation angle of a predetermined angle or more by applying a different correction value prediction formula depending on the region in the low elevation angle region, the predetermined value is predetermined. Since the positioning is performed by applying a predetermined correction value less than the predetermined angle as an actual correction value at a high elevation angle equal to or greater than the angle, a positioning error at a high elevation angle can be suppressed.

  According to the invention according to claim 4 or 8, since at least one of the offset processing of the correction value axis offset, the elevation angle axis offset, the rotation offset, and the enlargement / reduction offset is performed, the actual correction of the positioning date is further performed. It is possible to correct to a correction value close to the value.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is applied to a differential GPS (hereinafter abbreviated as DGPS) position specifying process will be described with reference to the drawings.
FIG. 1 schematically shows the mechanism of the DGPS system according to the present embodiment. The DGPS system is a system that corrects the position specifying error of the receiver on the mobile station 3 side using the positioning error in the receiver of the reference station 1 whose position is known, and within a certain range close to the reference station 1 The property that GPS positioning errors are almost the same is used. As shown in FIG. 1, a reference station 1 is installed at a fixed position. The reference station 1 is installed at a point where an accurate position is known in advance and is equipped with a receiver, and receives GPS signals from a plurality of GPS satellites 2 (2a, 2b...).

  When the distance from the GPS satellite 2 is measured based on the GPS signal received by the reference station 1, the pseudo distance to the virtual reference station 1a can be measured. The true distance calculated based on the exact position of the reference station 1 The positioning error can be accurately obtained by comparing the pseudo distance.

  In a certain range from the point where the reference station 1 is installed, the positioning error becomes almost the same value. The reference station 1 calculates a correction value based on the positioning error obtained by the reference station 1, and calculates a correction value prediction formula for deriving a correction value in the future from correction value groups obtained in the past as necessary. To do. At this time, the positioning error is different for each of the plurality of GPS satellites 2 (2a, 2b...), And also depends on the ionosphere, troposphere, and climate. Therefore, it is required to always use the latest correction value. At this time, for example, it is required to obtain with high accuracy a correction value prediction formula calculated in one cycle such as every several hours or every day, or a correction value at a predetermined time point derived from this correction value prediction formula.

  When the reference station 1 side obtains the correction value prediction formula or the correction value, it transmits it to the mobile station 3 side. The mobile station 3 side can measure the pseudorange between the GPS satellite 2 and the virtual mobile station 3a by measuring alone based on the GPS signal, but uses the correction value prediction formula or the correction value received from the reference station 1 side. Thus, the position can be specified with high accuracy by correcting the position error.

This will be specifically described below. In the present embodiment, the following system is applied.
FIG. 2 schematically shows an electrical configuration of the reference station side and the mobile station side using a block diagram. As shown in FIG. 2, the server 1b on the reference station 1 side is configured by a computer having a CPU and a memory, etc., and achieves each function shown in FIG. 2 by the hardware and software of the computer. Yes. The server 1b on the reference station 1 side functionally includes a control unit 4, and is configured by connecting the control unit 4 to a data transmission / reception unit 6 including a correction value database 5 and a GPS signal reception unit 6a. On the other hand, the positioning device 3b on the mobile station 3 side is similarly configured by a computer or the like provided with a CPU and a memory, and achieves each function shown in FIG. 2 by the hardware and software of the computer. Functionally, the positioning device 3b on the mobile station 3 side includes a data transmission / reception unit 7, a correction value generation unit 8, a pseudo (pseudo) distance correction unit 9, a GPS signal reception unit 10, an elevation angle calculation unit 11, and a correction value conversion unit. 12, a correction value prediction data storage memory 13 and a positioning calculation unit 14 are connected to each other.

  In the correction value database 5 as the storage unit of the reference station 1, a correction value group measured in the past, and / or a correction value prediction formula approximated and predicted in advance based on the correction value group is an accurate position of the reference station 1. Many are stored with the information. The correction value group and the correction value prediction formula are stored in the correction value database 5 in association with the elevation angle value of the GPS satellite 2 at the time of observation. Note that a plurality of reference stations 1 (for example, about 1200) are installed throughout the country, and the database 5 includes a correction value group for each GPS satellite 2 (2a, 2b...) Received by the reference station 1 and a correction value prediction formula. It is stored in association with the elevation angle value of the satellite 2 (2a, 2b...). The reference stations 1 nationwide store and hold a common correction value group and correction value prediction formula. The correction value group and the correction value prediction formula need not be stored for each GPS satellite 2 (2a, 2b...), But if stored for each GPS satellite 2 (2a, 2b. Specific accuracy can be further increased.

  The correction value changes daily depending on weather conditions such as ionosphere and weather. Error factors include atmospheric error, orbit error of GPS satellite 2, clock error of cesium atomic clock of GPS satellite 2, and the like. For this reason, when this correction value is calculated continuously in units of seconds, for example, the GPS satellites 2 (2a, 2b...) Are different every day. The correction value prediction formula is obtained by defining a correction value group by an expression approximated to an elevation angle value (0 to 90 degrees) and offsetting it using the correction value of the positioning date as necessary. The database 5 stores the approximate expression. The correction value prediction formula is a formula of an elevation value vs. correction value formula (for example, a polynomial (secondary formula, cubic formula, etc.), logarithmic function, exponent, etc. based on a prediction formula taking into account various error factors related to position detection by GPS. Function, ...)

  The control unit 4 receives a GPS signal from the GPS satellite 2 through the GPS signal receiving unit 6a, and determines the GPS at the time of observation from the accurate position information of the ephemeris (satellite orbit information) and the reference station (reference point) 1 included in the GPS signal. The elevation value of the satellite 2 (2a, 2b ...) is calculated. The control unit 4 stores the correction value group or / and the correction value prediction expression in association with the elevation angle value in the correction value database 5 and stores the latest correction value group or / and the correction value prediction expression and the elevation angle associated with each other. A function of distributing the value to the mobile station 3 through the data transmitting / receiving unit 6 is provided.

  On the mobile station 3 side, when the data transmission / reception unit 7 receives the correction value group or / and the correction value prediction formula, when the correction value generation unit 8 receives the correction value group or the correction value prediction formula through the data transmission / reception unit 7, the pseudo distance When the correction value group depending on the elevation angle value is received, the correction value conversion data is supplied to the correction value conversion unit 12.

  The GPS signal receiving unit 10 receives GPS signals distributed from the GPS satellites 2 (2a, 2b...) And gives them to the pseudo distance correction unit 9, the elevation angle calculation unit 11, and the positioning calculation unit 14. The elevation angle calculation unit 11 calculates the elevation angle value of each GPS satellite 2a, 2b... From the GPS signal. When the correction value conversion unit 12 accumulates correction value groups for all the elevation angle values from the correction value generation unit 8, the correction value conversion unit 12 converts the function into a correction value prediction formula depending on the elevation angle value calculated by the elevation angle calculation unit 11, and corrects the correction value prediction. The data is stored in the data storage memory 13.

  The pseudo distance correction unit 9 corrects the pseudo distance using the correction value group and the correction value prediction formula stored in the correction value prediction data storage memory 13. The positioning calculation unit 14 specifies the current position using the corrected pseudo distance as a true distance.

  Hereinafter, FIGS. 3 and 4 will be described with respect to a specific mode in which the elevation value and the correction value of the GPS satellite 2 are distributed from the reference station 1 and the mobile station 3 side applies the correction value corresponding to the elevation value to specify the position. The description will be given with reference.

  FIG. 4A shows data of a correction value group distributed by the reference station, and FIG. 4B shows a mode of data held by the mobile station. As shown in FIG. 4A, “correction values” corresponding to the number of all satellites are distributed corresponding to each satellite number (satellite identification number). FIG. 4B shows data stored in the correction value prediction data storage memory 13 on the mobile station 3 side. As shown in FIG. 4B, the elevation value and the correction value are stored in the correction value prediction data storage memory 13 on the mobile station 3 side in association with each other. These elevation angle values and correction values are stored for the number of all satellites corresponding to each satellite number (satellite identification number).

FIG. 3A schematically shows processing on the reference station side, and FIG. 3B schematically shows processing on the mobile station side.
As shown in FIG. 3A, on the reference station 1 side, when the control unit 4 receives a GPS signal from the GPS satellite 2 through the GPS signal receiving unit 6 a of the data transmitting / receiving unit 6, a correction value is obtained from the observation data of an arbitrary reference station 1. Is calculated (S1). Next, the control unit 4 calculates the elevation angle value of the GPS satellite 2 at the time of observation from the ephemeris (satellite orbit information) and a predetermined accurate position of the reference station 1 (S2), and corrects the elevation angle value in association with this elevation angle value. The value is stored in the correction value database 5. The control unit 4 associates the calculated elevation angle value with the correction value and distributes them to the mobile station 3 side (S3). In this case, the correction value and the elevation angle value may be distributed after being accumulated for an arbitrary predetermined period, or may be distributed immediately together with the correction value when the elevation angle value can be calculated.

  On the other hand, on the mobile station 3 side, the positioning calculation unit 14 performs positioning calculation even when the correction value and the elevation angle value are not transmitted from the reference station 1 side (T1). Next, the distributed elevation angle value and correction value are received through the data transmission / reception unit 7 (T2), and the process is repeated from step T1 until all the elevation angle values are accumulated in the correction value prediction data storage memory 13 (T3). The correction value conversion unit 12 converts the value into an elevation value-dependent correction value prediction formula and stores it in the correction value prediction data storage memory 13.

  Thereafter, in the positioning device 3b on the mobile station 3 side, the positioning calculation unit 14 determines whether or not the current position can be detected by receiving the GPS signal by the GPS signal receiving unit 10, and can detect the current position. In some cases, the current position is detected and then the process proceeds to step T6. If the current position cannot be detected (T4: NO), positioning is performed independently (T5).

  Thereafter, the positioning device 3b on the mobile station 3 side calculates an elevation angle value from the ephemeris information and the current position information (T6), and the correction value and elevation angle value stored in the correction value prediction data storage memory 13 are calculated. Then, it is determined whether there is data having the same elevation angle value as the calculated elevation angle value (T7). In this case, it is determined whether or not the correction value and elevation value data stored in the correction value prediction data storage memory 13 and the calculated elevation value data are data obtained from the same GPS satellite 2. In step T7, the data is obtained from the same GPS satellite 2 (2a, 2b).

  When correction values associated with the same elevation angle value are accumulated (T7: YES), the corresponding data is applied as a correction value (T8), and the correction values associated with the same elevation angle value are accumulated. If not (T7: NO), a correction value corresponding to the calculated elevation angle calculated by linearly interpolating the two nearest elevation angles in the stored elevation angle values is calculated, and the calculated correction The value is applied as an actual correction value (T9). Then, the positioning calculation unit 14 performs positioning by applying the calculated correction value.

  According to the present embodiment, on the reference station 1 side, the correction value calculated based on the GPS signal (satellite information) received from the GPS satellite 2 (2a, 2b...) Is the elevation angle of the GPS satellite 2 (2a, 2b...). The mobile station 3 side stores it in association with the value, and the elevation angle of the GPS satellite 2 received by the mobile station 3 based on the GPS signal (satellite information) received by the mobile station 3 from the GPS satellite 2 (2a, 2b...). Since the positioning is performed by applying the correction value corresponding to the calculated elevation angle value, the position can be accurately identified.

  Further, when the time-dependent correction value is applied, when the mobile station 3 moves, a correction value prediction formula or correction value used for correction value prediction every time the reference station 1 to which the correction value is distributed is changed. However, in this embodiment, since the elevation value-dependent correction value is applied, the server 1b of the reference station 1 does not need to distribute information for each reference point, and information common to all reference points is received. Broadcast distribution is performed and the distribution information is received.

  Further, since the positioning device 3b can obtain information common to the whole country, it is not necessary to transmit a rough position to the server 1b, and communication frequency and communication cost can be suppressed. Therefore, even if the positioning device 3b cannot communicate with the server 1b, DGPS positioning can be performed in a stand-alone environment as long as it holds a correction value or a correction value prediction formula used for correction value prediction.

(Second Embodiment)
5 and 6 show a second embodiment of the present invention. The difference from the previous embodiment is that a correction value prediction formula is distributed instead of distributing a correction value. is there. The same parts as those of the previous embodiment are denoted by the same reference numerals, and the processing steps similar to those of the aforementioned embodiment will be described by adding the symbol “a” to the step number, and different parts will be described.

  FIG. 5A schematically shows processing on the reference station side, and FIG. 5B schematically shows processing on the mobile station side. As shown in FIG. 5A and FIG. 5B, when the control unit 4 receives a GPS signal from the GPS satellite 2 through the GPS signal receiving unit 6a of the data transmitting / receiving unit 6 on the reference station 1 side, A correction value is calculated from the observation data of the reference station 1 (S1).

  Next, the control unit 4 calculates the elevation value of the satellite at the time of observation from the position of the ephemeris (satellite orbit information) and the reference station 1 (reference point) (S2). Next, the control unit 4 stores the calculated elevation angle value and the correction value in association with each other in the correction value database 5 (S3).

  FIGS. 6A and 6B show data that the reference station 3 holds for generating a correction value prediction formula. The data held for the correction value prediction is, for example, data that is held in order of date in a unit of one day. As shown in FIGS. 6 (a) and 6 (b), in the data for one day, correction values are stored and held for each of the number of all satellites when the elevation angle value is 1 degree to 90 degrees. .

  Next, the control unit 4 determines whether or not the elevation angle value and the correction value can be accumulated for a certain predetermined period (S4). An approximate expression that approximates the correction value is calculated and used as a correction value prediction expression (S5) and distributed to the mobile station 3 side (S6). Note that the data shown in FIGS. 6A and 6B may be held for an arbitrary period. In principle, the correction value prediction formula is preferably generated in step S5 based on the latest data. However, the correction value prediction formula may be calculated by using all of these data by statistical processing or the like.

  FIG. 6C schematically shows data distributed by the reference station 3. As shown in FIG. 6 (c), the data distributed by the reference station 3 includes the prediction formula generation time, the prediction formula form information corresponding to each satellite number, and the prediction formula coefficient information 1, 2, 3,. is there. If the correction value itself is transmitted, transmission / reception processing of, for example, 100,000 bytes or more per day is required. However, if the correction value prediction formula is distributed, the prediction formula form information (polynomial (secondary formula, cubic formula, etc.), exponent Function, logarithmic function, etc.) and coefficient information of the prediction formula (in the case of a quadratic equation, 0th order, 1st order, 2nd order coefficient) are transmitted by, for example, about several hundred to several thousand bytes. Therefore, the amount of information during transmission / reception can be reduced as much as possible. In particular, when the ephemeris (orbit information from the GPS satellite 2) is switched, the tendency of the correction value to change may change. In this case, it is preferable to transmit the form of the prediction formula. Note that it is not necessary to distribute the predictive form information as necessary.

  On the mobile station 3 side, when the correction value prediction formula is distributed from the reference station 1, information on the correction value prediction formula is acquired through the data transmitting / receiving unit 7 and held in the correction value prediction data storage memory 13 (T2a). Next, the GPS signal receiving unit 10 acquires an ephemeris from the GPS satellite 2 and calculates a pseudorange (T10). Next, it is determined whether or not the current position can be detected (T4). If the current position can be detected, the current position is detected, and then the process proceeds to step T6. However, if the current position cannot be detected (T4: For NO), positioning calculation is performed independently (T5).

  Next, on the mobile station 3 side, an elevation angle value is calculated from the ephemeris information and the current position information (T6), and the elevation angle value calculated in the correction value prediction formula stored in the correction value prediction data storage memory 13 is calculated. Is calculated by substituting (T7), and the calculated correction value is applied as an actual correction value to perform positioning calculation (T1). Next, on the mobile station 3 side, for example, the positioning calculation unit 14 or the like determines whether or not a predetermined time has elapsed since the generation time of the prediction expression given to the correction value prediction expression transmitted from the reference station 3 side, that is, correction. It is determined whether or not the expiration date of the value prediction formula has passed (T11), and when it is determined that the expiration date has passed, the process returns to step T2a to acquire the correction value prediction formula from the reference station 1 again. In addition, since the change of the correction value with respect to the elevation angle value has the same tendency in about one month, the same data can be used for the correction value prediction processing for about one month. As shown in the prior art, when the time-dependent correction value prediction formula is applied, the expiration date is, for example, about 1 week at the longest. Therefore, when the technical idea of the present embodiment is applied, the expiration date can be significantly extended. . Even if the expiration date has passed, a new correction value prediction formula can always be obtained by making an inquiry to the server 1b on the reference station 1 side. In addition, as a criterion for determining whether or not the correction value prediction formula is appropriate, whether the correction value prediction formula is not deviated from the correction value received other than the expiration date. It can also be determined by determining whether or not the ephemeris has been switched.

Conversely, on the mobile station 3 side, if it is determined in step T11 that the expiration date of the correction value prediction formula has not elapsed, the process returns to step T10 to acquire the ephemeris and repeatedly execute the pseudo distance calculation process.
According to the present embodiment, since the correction value corresponding to the time is converted into the correction value corresponding to the elevation angle value on the reference station 1 side, the same operational effects as the above-described embodiment are obtained. Further, since the correction value prediction formula is distributed from the reference station 1 side, the amount of information at the time of transmission / reception can be reduced as much as possible.

(Third embodiment)
7 and 8 show a third embodiment of the present invention. The difference from the previous embodiment is that the reference station 1 side converts a correction value corresponding to time into a correction value corresponding to an elevation angle value, The elevation angle value and the correction value are distributed, and an equation that approximates the correction value is calculated on the mobile station 3 side to obtain a correction value prediction equation. The same parts as those of the above-described embodiment will be described with the same reference numerals, and different parts will be described below.

  FIG. 7A schematically shows processing on the reference station side, and FIG. 7B schematically shows processing on the mobile station side. As shown in FIG. 7 (a), on the reference station 1 side, the control unit 4 calculates a correction value from observation data of an arbitrary reference station 1 (S1), and based on the ephemeris (satellite orbit information) and the position of the reference station. The elevation angle value of the satellite at the time of observation is calculated (S2). Next, the control unit 4 distributes the calculated elevation angle value and the correction value in association with each other (S3).

FIG. 8A schematically shows the contents of data distributed by the reference station 1. As shown in FIG. 8A, the control unit 4 of the reference station 1 transmits correction values corresponding to the respective satellite numbers for the number of all satellites.
On the mobile station 3 side, as shown in FIG. 7B, the GPS signal receiving unit 10 receives the GPS signal from the GPS satellite 2 to acquire the ephemeris information, and the positioning calculation unit 14 calculates the pseudo distance ( T10). The positioning calculation unit 14 determines whether or not the current position can be detected (T4). If the current position can be detected, the current position is detected and the process proceeds to step T6, but the current position cannot be detected. If it is determined, positioning calculation is performed independently (T5).

  Next, the elevation angle calculation unit 11 calculates an elevation angle value from the ephemeris information and the current position information (T6). Next, the positioning calculation unit 14 performs positioning (T1), receives correction values + elevation values from the reference station 1 for the number of all satellites, and accumulates them (T2). FIG. 8B schematically shows data stored on the mobile station 3 side. As shown in FIG. 8B, the correction value prediction data storage memory 13 of the mobile station 3 stores all the satellite numbers, the elevation values at the satellite numbers, and the correction values associated with the elevation values. The number of satellites will be accumulated. It is determined whether or not the correction value + elevation value for all the elevation values (from the lowest elevation value (1 degree) to the highest elevation value (90 degrees)) can be accumulated for all the satellites (T3). Then, an equation that approximates the correction value for the elevation angle value is calculated from the accumulated data, and is used as a correction value prediction equation (T12).

  FIG. 8C schematically shows correction value prediction formula data held on the mobile station 3 side. As shown in FIG. 8C, the correction value prediction data storage memory 13 includes the generation time of the correction value prediction formula, the satellite number, the form of the prediction formula, and the coefficients 1, 2, and 3 of the prediction formula. The number of all satellites is stored. Next, the positioning calculation unit 14 applies the elevation value calculated in step T6 using the calculated correction value prediction formula, and performs positioning by substituting the elevation value calculated in step T7 into the correction value prediction formula. (T1) Repeat.

  According to the present embodiment, the reference station 1 side converts the correction value corresponding to the time into a correction value corresponding to the elevation angle value, distributes the elevation angle value and the correction value for the entire elevation angle value, and the mobile station 3 side increases the elevation angle. Since an equation that approximates the correction value associated with the value and the elevation value is calculated and the correction value prediction equation is applied as the correction value prediction equation, positioning is performed. .

(Fourth embodiment)
9 to 12 show a fourth embodiment of the present invention, in which a correction value or a correction value prediction formula is offset-corrected. The same parts as those of the previous embodiment are denoted by the same reference numerals and the description thereof is omitted. Since there is a clock error inherent to each GPS satellite 2 (2a, 2b...), The correction value change tendency is similar, but the absolute value may be different. Therefore, when past correction values are used as they are or when they are used as a function by a correction value prediction formula, the values may deviate from the correction values for the positioning date, and the deviation is eliminated by offset correction of the correction values. Positioning by DGPS can be performed with higher accuracy. In the present embodiment, an embodiment is described in which offset correction processing is performed using data obtained by functionalizing a correction value with respect to an elevation angle value.

  9 to 12 show an example of the offset processing. FIG. 9 shows an example in which the correction value is offset by parallel movement along the correction value axis. For example, it is preferable to obtain several correction values for the positioning date, add an average value of the deviation of the correction value from that value, and translate along the correction value axis to match the correction data for the positioning date. Then, a more accurate correction value can be obtained and a more accurate position can be specified.

  FIG. 10 shows an example of offsetting the correction value along the elevation value axis. As shown in FIG. 10, by obtaining several correction values for the positioning date, adding an average value of the deviation of the elevation angle value from that value, and moving in parallel along the elevation value axis, the correction data for the positioning date is obtained. It is matched. FIG. 11 shows an example of the rotation offset process in the prediction formula of the correction value versus the elevation angle value. As shown in FIG. 11, several correction values for the positioning date may be acquired, and the rotation offset process may be performed so as to match the correction values at the predetermined elevation angle values at the several points.

  FIG. 12 shows an example in which the enlargement / reduction offset is performed in the prediction formula of the correction value versus the elevation angle value. As shown in FIG. 12, the enlargement / reduction offset processing may be performed so as to match the correction value on the positioning date by multiplying by α in the elevation value axis direction and by β in the correction value axis direction.

  Note that the required offset amount may differ between the low elevation angle value (about 15 degrees) and the medium elevation angle value to the high elevation angle value (20 degrees to 90 degrees). In this case, the offset amount is set to a predetermined elevation angle value. The offset amount may be switched between the above and less than that value, and in the case of a low elevation angle value, since the reliability is low, the offset value may not be used and the correction value may not be used.

  These offset processes may be performed by either the server 1b on the reference station 1 side or the positioning device 3b on the mobile station 3 side. It is preferable to perform the offset process on the server 1b side because the correction value prediction formula can be offset according to the positioning situation (season, weather, atmospheric pressure, temperature, etc.). Further, if the positioning device 3b on the mobile station 3 side can detect the positioning situation (season, weather, atmospheric pressure, temperature, etc.), the correction value prediction formula is properly used according to the positioning situation, or the correction value prediction formula according to the positioning situation. May be offset processed. The offset calculation process is preferably performed when the positioning device 3b accumulates the correction value prediction formula or when converting the correction value prediction function into a correction value prediction formula.

For example, the server 1b of the reference station 1 creates a correction value prediction formula according to the weather in the case of sunny, rainy, cloudy, and snow, and statistically processes past correction values and the like to obtain an offset value and calculate the weather condition The correction value prediction formula is offset-processed according to the position, the positioning device 3b on the mobile station 3 side receives all the correction value prediction formulas once, receives the weather information of the positioning date from another medium, and the positioning device 3b It is preferable to determine which correction value prediction formula is applicable according to the information, select the correction value prediction formula, and obtain the correction value.
According to the present embodiment, since the correction value axis offset, the elevation value axis offset, the rotation offset, and the enlargement / reduction offset are performed, it is possible to correct the correction value closer to the actual correction value on the positioning date.

(Fifth embodiment)
FIG. 13 shows a fifth embodiment of the present invention. The difference from the previous embodiment is that even when it is assumed that the error of the correction value becomes large at a high elevation angle of a predetermined angle or more. At high elevation angles greater than or equal to a predetermined angle, positioning is performed by applying a predetermined correction value below the predetermined angle as an actual correction value. The same parts as those of the above-described embodiment are denoted by the same reference numerals, description thereof will be omitted, and different parts will be described.

  As shown in FIG. 13 (a), when correction values are acquired in various places throughout the country, even if the elevation angle value of the GPS satellite 2 is different within a predetermined range of about 20 to 75 degrees, the correction value prediction formula indicates the value of the elevation angle value. It has been found that the prediction error falls within the predetermined error range within the predetermined range. However, if the elevation value deviates from the predetermined range, a correction value prediction formula in which the correction value is diffused depending on the acquired value at the maximum elevation angle will result in a large error. However, in reality, in the range of the high elevation angle value, the change in the positioning error according to the change in the elevation angle is small, and it is often the same value.

  Therefore, as shown in FIG. 13B, a single correction value is selected in a high elevation angle range (eg, 60 to 75 degrees) that is equal to or greater than a predetermined angle (eg, 60 degrees), and the one fixed predetermined value. Is applied as the correction value prediction value. Then, even if the correction value prediction formula is diffused, positioning can be performed by applying an accurate correction value.

  According to the present embodiment, even if the error of the correction value becomes large in the high elevation angle range above the predetermined angle, the predetermined correction value less than the predetermined angle (for example, the correction value at 60 degrees) in the high elevation angle range above the predetermined angle. Since positioning is performed by applying it as an actual correction value, a positioning error at a high elevation angle value can be suppressed.

(Other embodiments)
The present invention is not limited to the above embodiment, and for example, the following modifications or expansions are possible.
Although the embodiment in which the elevation value and the correction value or the correction value prediction formula are associated with each other and distributed to the positioning device 3b on the mobile station 3 side is shown from the server 1b of the reference station 1, the measurement time and the correction value or the correction value prediction formula are shown. Is distributed to the positioning device 3b on the mobile station 3 side, and the positioning device 3b on the mobile station 3 side uses the correction value or the correction value prediction formula associated with the time as the correction value associated with the elevation angle value or You may make it convert into a correction value prediction type | formula.

Explanatory drawing which shows roughly the mechanism of the DGPS system which shows the 1st Embodiment of this invention Block diagram schematically showing the electrical configuration of the reference station side and mobile station side A flowchart schematically showing processing on the reference station side and the mobile station side The figure which shows roughly the aspect of the data which a reference station distributes, and the data which a mobile station hold | maintains FIG. 3 equivalent view showing the second embodiment of the present invention 4 equivalent figure FIG. 3 equivalent view showing a third embodiment of the present invention 4 equivalent figure Explanatory drawing of the offset process which shows the 4th Embodiment of this invention (the 1) Explanatory drawing of offset processing (part 2) Explanatory drawing of offset processing (part 3) Explanatory drawing of offset processing (part 4) Explanatory drawing which shows the malfunction of the correction value prediction formula at the time of a high elevation angle, and its correction example according to the fifth embodiment of the present invention.

Explanation of symbols

  In the drawings, reference numeral 1 is a reference station, 1b is a server, 3 is a mobile station, 3b is a positioning device, and 13 is a correction value prediction data storage memory (storage means).

Claims (8)

Correlating the correction value or the correction value prediction formula calculated based on the first satellite information received by the reference station from the satellite with the elevation angle value of the satellite,
Based on the position calculation information obtained by calculating the position of the mobile station based on the second satellite information received by the mobile station from the satellite and the orbit information included in the second satellite information, the elevation angle of the satellite received by the mobile station is determined. A positioning method characterized in that positioning is performed by applying a correction value or a correction value prediction formula associated with the elevation angle value corresponding to the calculated elevation angle calculation value.   The positioning is performed by applying a correction value or a correction value prediction formula associated with an elevation value under a condition in which the satellite from which the reference station has received satellite information matches the satellite from which the mobile station has received satellite information. The positioning method according to claim 1.   3. When positioning is performed by applying a correction value prediction formula, positioning is performed by applying a predetermined correction value below the predetermined angle as an actual correction value at a high elevation angle greater than or equal to a predetermined angle. Positioning method.   4. The positioning method according to claim 1, wherein the correction value is subjected to at least one type of offset processing of a correction value axis offset, an elevation value axis offset, a rotation offset, and an enlargement / reduction offset. . A positioning device configured to be mounted on a mobile body and for identifying the position of the mobile station based on first satellite information received by the reference station from the satellite and second satellite information received by the mobile station from the satellite,
Storage means for storing a correction value or a correction value prediction formula calculated based on the first satellite information received by the reference station from the satellite and the elevation angle value of the satellite received by the reference station in association with each other;
The elevation angle of the satellite received by the mobile station based on the position calculation information obtained by calculating the position of the mobile station based on the second satellite information received by the mobile station from the satellite and the satellite orbit information included in the second satellite information. A positioning device comprising: positioning means for applying a correction value or a correction value prediction formula associated with the stored elevation angle value corresponding to the calculated elevation angle value.   Positioning is performed by applying a correction value or a correction value prediction formula associated with the stored elevation angle value under the condition that the satellite from which the reference station has received satellite information and the satellite from which the mobile station has received satellite information are matched. The positioning device according to claim 5.   7. When positioning is performed by applying a correction value prediction formula, positioning is performed by applying a predetermined correction value below the predetermined angle as an actual correction value at a high elevation angle of a predetermined angle or more. Positioning device.   8. The positioning apparatus according to claim 5, wherein the correction value is subjected to at least one of offset processing of correction value axis offset, elevation angle axis offset, rotation offset, and enlargement / reduction offset. .

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