WO2017187681A1

WO2017187681A1 - Positioning device, positioning system, and positioning method

Info

Publication number: WO2017187681A1
Application number: PCT/JP2017/002661
Authority: WO
Inventors: 雄田中
Original assignee: ソニー株式会社
Priority date: 2016-04-27
Filing date: 2017-01-26
Publication date: 2017-11-02
Also published as: JP2017198531A

Abstract

[Problem] Reduced positioning accuracy and inability to carry out positioning smoothly. [Solution] A positioning device provided with a reception unit for receiving radio waves from satellites, a detection unit for detecting the satellites on the basis of the radio waves from the satellites received by the reception unit, and a positioning unit for estimating an integer bias using observed values based on the radio waves received from a reference station and the satellites and carrying out positioning, wherein the positioning unit carries out, in parallel, positioning based on a first integer bias determined on the basis of observed values for a first satellite combination and estimation of a second integer bias on the basis of observed values for a second satellite combination and is capable of switching from positioning using the first integer bias to positioning using the second integer bias.

Description

Positioning device, positioning system, positioning method

The present disclosure relates to a positioning device, a positioning system, and a positioning method.

In recent years, interference has been performed by measuring the phase of radio waves (carrier waves) from GPS satellites at two points, a reference station whose position is known and an unknown point whose position is unknown, and performing positioning using the measured observation values. Positioning is attracting attention. Observed GPS satellites orbit around a predetermined orbit, and the position and number of observed GPS satellites change over time. In the interference positioning, information (integer value bias described later) used for positioning is recalculated by the change in the state of the GPS satellite.

Patent Documents 1 and 2 disclose a positioning device that copes with the change in the state of the GPS satellite described above. The positioning device disclosed in Patent Document 1 estimates the integer value bias after the change using information calculated before the change in the state of the GPS satellite occurs. Further, the positioning device disclosed in Patent Document 2 estimates an integer bias using a spare reference satellite when data of a reference satellite having a large elevation angle cannot be used.

JP 2003-185728 A JP 2006-003208 A

Although the positioning device disclosed in Patent Document 1 copes with the change in the state of the GPS satellite described above, the accuracy of positioning is lowered by taking over the information before the change. Further, the positioning device disclosed in Patent Document 2 cannot perform positioning smoothly because the positioning solution is calculated after the reference satellite cannot be used.

Therefore, the present disclosure proposes a new and improved positioning device, positioning system, and positioning method that can smoothly switch positioning without lowering positioning accuracy.

According to the present disclosure, a reception unit that receives radio waves from a satellite, a detection unit that detects a satellite based on radio waves from the satellite received by the reception unit, and an observation value based on radio waves received from a reference station and the satellite A positioning unit that estimates an integer value bias using and performs positioning, and the positioning unit includes positioning based on a first integer value bias determined based on an observation value of a first combination of satellites, and , And estimating the second integer value bias based on the observation value of the second combination of satellites in parallel, and the positioning unit performs the second alignment from the positioning using the first integer value bias. A positioning device is provided that switches to positioning using numerical bias.

Further, according to the present disclosure, a receiving unit that receives radio waves from a satellite, a detection unit that detects a satellite based on radio waves from the satellite received by the receiving unit, a reference station, and a radio wave received from the satellite A positioning unit that estimates the integer value bias using the observation value and performs positioning, and the positioning unit is based on the first integer value bias determined based on the observation value of the first combination of the satellites The positioning and the estimation of the second integer value bias based on the observation value of the second combination of the satellites are performed in parallel, and the positioning unit performs the second operation from the positioning using the first integer value bias. A positioning system is provided that switches to positioning using an integer value bias.

In addition, according to the present disclosure, using the observation value based on the radio wave received from the satellite, detecting the satellite based on the radio wave received from the satellite, and the radio wave received from the reference station and the satellite Estimating the integer bias and performing positioning, based on the first integer bias determined based on the first combination observations of the satellites, and on the observations of the second combination of satellites Estimating the second integer value bias in parallel, and switching from positioning using the first integer value bias to positioning using the second integer value bias. Is provided.

As described above, according to the present disclosure, positioning can be switched smoothly without any deterioration in positioning accuracy.

The above effects are not necessarily limited, and any of the effects shown in the present specification or other effects that can be grasped from the present specification are exhibited together with or in place of the above effects. May be.

FIG. 1 is a schematic diagram illustrating the principle of interference positioning. FIG. 2 is a schematic diagram illustrating the principle of obtaining an integer value bias in interference positioning. FIG. 3 is a diagram illustrating a path of radio waves with respect to an elevation angle of a GPS satellite viewed from a mobile station. FIG. 4 is a schematic diagram illustrating a configuration of a system according to an embodiment of the present disclosure. FIG. 5 is a block diagram illustrating a configuration of the receiver according to the embodiment of the present disclosure. FIG. 6 is a flowchart illustrating an operation example of performing interference positioning in the embodiment of the present disclosure. FIG. 7 is a flowchart illustrating an operation example when the mobile station detects a new satellite in the embodiment of the present disclosure. FIG. 8 is a diagram illustrating an operation example when a mobile station detects an unusable satellite in the embodiment of the present disclosure.

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

The description will be given in the following order.
0. Principle of interference positioning 1. Integer value bias estimation method 2. System configuration example Configuration of mobile station 4. 4. Example of operation when mobile station performs interference positioning 5. Example of operation when a mobile station detects a new satellite 6. Selection method of satellite combination 7. Example of operation when a mobile station detects an unusable satellite Supplement 9 Conclusion

<0. Interference positioning principle>
FIG. 1 is a diagram illustrating the principle of interference positioning. FIG. 1 shows a GPS satellite 100, a reference station 200 whose position is known, and a mobile station 300 whose position is unknown. The reference station 200 and the mobile station 300 include

GPS receivers

202 and 302 that receive radio waves from the GPS satellite 100, respectively. The receiver 302 is an example of a positioning device that performs positioning by receiving radio waves from the GPS satellite 100.

The GPS satellite 100 orbits in a predetermined orbit and the position of the GPS satellite 100 is known. The GPS satellite 100 uses frequencies of L1 band (1575.42 MHz) and L2 band (1227.6 MHz) as carrier waves. The carrier wave includes a ranging code and a navigation message as a modulated signal.

The ranging code is used to measure the distance between the GPS satellite 100 and the

receivers

202 and 302. Ranging codes include C / A codes for private use and P codes for users authorized by the US Department of Internal Affairs and Communications. The C / A code is transmitted in the L1 band, and the P code is transmitted in the L1 and L2 bands.

The navigation message includes data indicating the health status of the GPS satellite 100, an ephemeris, and a clock correction coefficient. The ephemeris includes parameters used to specify the position and orbit of the GPS satellite 100.

The reference station 200 and the mobile station 300 observe the radio wave transmitted by the GPS satellite 100 with the

GPS receivers

202 and 302, and use the carrier phase and the pseudo distance (the true distance from the GPS satellite 100 to the GPS receivers 202 and 302) as the observed values. The distance including the error is calculated. The

GPS receivers

202 and 302 receive the radio wave from the GPS satellite 100 to capture the GPS satellite 100, and receive the ephemeris broadcast from the GPS satellite to identify the position and orbit of the GPS satellite 100.

In general, in interference positioning, the reference station 200 transmits the observed observation values (carrier phase and pseudorange) and position information of the reference station 200 to the mobile station 300. The mobile station 300 transmits the observation values of the reference station 200, the mobile station The mobile station 300 is positioned by calculating the relative position of the mobile station 300 with respect to the reference station 200 using the observation values observed at 300.

Also, the mobile station 300 calculates a double difference between the observed value at the reference station 200 and the observed value at the mobile station 300 in order to obtain an integer value bias described later. This double difference calculation is done to cancel the receiver clock error and atmospheric delays and the initial phase bias of the receiver and satellite. Next, the mobile station 300 obtains an integer value bias and a relative position of the mobile station 300 with respect to the reference station 200 indicated by an arrow in FIG. 1 using a Kalman filter from the calculated double difference. Since the integer value bias calculated at this time is a real number, the mobile station 300 further obtains an integer value solution of the integer value bias by the integer least square method. Then, the mobile station 300 obtains the relative position again using the integer value bias that is the calculated integer value solution.

Note that the wavelength of the carrier wave of the GPS satellite 100 is about 19 cm in the above-described L1 band and about 24 cm in the L2 band. The

GPS receivers

202 and 302 have a high accuracy of observation of the carrier wave phase, and a carrier wave having such a wavelength can be measured by interference positioning with an accuracy of several millimeters to several centimeters.

<1. Integer bias estimation method>

Here, the subscript B means the reference station 200. As can be understood from the expression (3), the clock error δ ⁱ on the satellite side is eliminated by the single phase difference between the reference station 200 and the mobile station 300. However, in the single phase difference between the reference station 200 and the mobile station 300, the clock errors δ _A and δ _B on the reference station and mobile station side are not eliminated. Therefore, in order to eliminate the clock error on the reference station 200 and the mobile station 300 side, the double phase difference between the GPS satellite i102 and the GPS satellite j104 is calculated.

Integer bias is estimated by applying the Kalman filter algorithm using Equation (5) and Equation (6) as observation equations. The integer bias estimated by applying the Kalman filter is a real number, which is called a Float solution. Here, an integer least square method is used to obtain an integer solution.

The integer least square method is a method for searching for a solution that satisfies the least square method under the constraint that the integer bias is an integer. An integer value bias obtained by applying the integer least square method is called a Fix solution. This Fix solution is evaluated by a test called Ratio Test. In the Ratio Test, the optimal solution obtained by the integer least square method is compared with the suboptimal solution. Then, the optimum solution is adopted as the Fix solution when the element ratio (Ratio factor) that is the ratio of the optimum solution to the next best solution (suboptimal solution / optimum solution) exceeds a predetermined threshold (for example, 3). Here, the large element ratio described above indicates that the variance of the solution obtained by the integer least square method is small. That is, it is estimated that the accuracy of the solution (integer value bias) obtained by the integer least square method is high. In the interference positioning, the mobile station performs positioning using the integer value bias of the Fix solution in order to perform highly accurate positioning.

The double difference between the carrier phase and the pseudorange described above is based on a combination of m (m−1) / 2 sets of GPS satellites when m GPS satellites 100 are observed at the reference station 200 and the mobile station 300. Calculated. Since there are two observation values observed from one satellite, that is, the pseudorange and the carrier phase, there are m (m−1) combinations of double difference calculated. Here, as a combination of GPS satellites used for estimating the integer value bias, not all of the above-described m (m−1) / 2 sets need be used, and some of the satellite combinations are used. Also good. However, four or more satellites are used to estimate the integer value bias.

Also, in the above-described integer value bias estimation process, the above-described double difference is preferably calculated using the GPS satellite 100 having a large elevation angle from the reference station 200 and the mobile station 300 as the reference satellite. FIG. 3 is a diagram illustrating an example of the relationship between the positions of the two

GPS satellites

106 and 108 and the position of the mobile station 300. The GPS satellite 106 is a satellite whose elevation angle viewed from the mobile station 300 is relatively larger than that of the GPS satellite 108. As can be seen from FIG. 3, when the distance between the mobile station 300 and the GPS satellite 106 is compared with the distance between the mobile station 300 and the GPS satellite 108, the distance between the mobile station 300 and the GPS satellite 106 is smaller. Thus, since the distance between the ionosphere and the troposphere that passes through decreases as the elevation angle of the satellite viewed from the mobile station 300 increases, the ionosphere delay I and troposphere delay T decrease. Therefore, when observation is performed using a GPS satellite common to the reference station 200 and the mobile station 300, a GPS satellite having a large elevation angle is preferably selected as the reference satellite in order to perform highly accurate positioning.

As described above, when the double difference is calculated using the GPS satellite 100 having a large elevation angle as a reference satellite, the calculated double difference is a combination of m-1 satellites with respect to the number m of observed satellites. Calculated based on However, as described above, as a combination of GPS satellites used for estimating the integer value bias, not all of m−1 sets may be used, and a combination of some satellites may be used.

<2. Example of system configuration>
In the above, the positioning principle of interference positioning and the estimation method of integer value bias have been described. Hereinafter, an example of a system configuration according to an embodiment of the present disclosure will be described. In this embodiment, a positioning device that performs positioning by receiving radio waves from a satellite will be described. As a positioning device, for example, there is a receiver 302 provided in a mobile station 300 as shown in FIG.

The system according to the present embodiment includes a GPS satellite 100, a reference station 200 whose position is known, a mobile station 300, and a network 400. The reference station 200 and the mobile station 300 include

receivers

202 and 302. The GPS satellite 100 transmits radio waves and broadcasts distance measurement codes and navigation messages in the same manner as described above. Further, the reference station 200 and the mobile station 300 receive the radio wave transmitted from the GPS satellite 100, capture the GPS satellite 100, and specify the position and orbit of the GPS satellite 100 using the received navigation message. Further, the reference station 200 and the mobile station 300 observe the observation value based on the radio wave received from the GPS satellite 100.

The network 400 carries information from the reference station 200 or the mobile station 300. The network 400 may be a public network such as the Internet or a network having a wireless interface such as a mobile phone network.

The position of the reference station 200 is known, and the reference station 200 includes a receiver 202 that can measure the carrier phase from the GPS satellite 100. For example, the reference station 200 may be a structure installed in an urban area, such as a building or a traffic light or a base station of a mobile phone network, with a receiver 202 that can measure the carrier phase from the GPS satellite 100. The reference station 200 may be an electronic reference point installed by the Geographical Survey Institute. In FIG. 4, only one reference station 200 is shown. However, a plurality of reference stations 200 may be installed in this system.

The mobile station 300 is shown as a vehicle in FIG. However, in this embodiment, the mobile station 300 is not limited to a vehicle, and may be a device that can be carried by a person such as a mobile phone or a game machine. Further, the mobile station 300 may be a ship, and the mobile station 300 may be any device as long as the device includes the receiver 302 that can measure the carrier phase from the GPS satellite 100.

Also, the mobile station 300 receives information regarding the observation value (carrier phase and pseudorange) of the reference station 200 and the position of the reference station 200 via the network 400. Then, the mobile station 300 performs interference positioning using the information received from the reference station 200 and the observation value obtained by the mobile station 300 observing the radio wave from the GPS satellite 100.

<3. Configuration of mobile station receiver>
The configuration example of the system according to the embodiment of the present disclosure has been described above. Next, the configuration of receiver 302 of mobile station 300 will be described using FIG. The receiver 302 is provided in the mobile station 300, and the receiver 302 includes a GPS receiver 304, a satellite detector 306, a communication unit 308, and a positioning unit 310. In addition, the positioning unit 310 includes an integer value bias estimation unit 312 and a positioning execution unit 314.

The GPS receiving unit 304 receives radio waves from the GPS satellites 100, and sends signals based on the received radio waves from the GPS satellites 100 to the satellite detection unit 306 and the positioning unit 310. The satellite detection unit 306 identifies the number, position, and orbit of the GPS satellites 100 to be observed based on the signal received from the GPS reception unit 304. Then, the satellite detection unit 306 sends the number, position, and orbit of the identified GPS satellites 100 to the positioning unit 310. Here, when the satellite detection unit 306 specifies the position and orbit of the GPS satellite 100, the satellite detection unit 306 uses the ephemeris included in the navigation message described above.

The communication unit 308 is used to perform wireless communication with other devices. The communication unit 308 receives information regarding the observation value observed at the reference station 200 and the position of the reference station 200 from the reference station 200 via the network 400, and sends the received information to the positioning unit 310. The communication unit 308 may be a transceiver used for a wireless LAN such as Bluetooth (registered trademark) or Wi-Fi, or a mobile phone network such as LTE (Long Term Evolution).

The integer value bias estimation unit 312 calculates the observation value based on the radio wave received from the satellite received by the GPS reception unit 304. The integer value bias estimation unit 312 estimates the integer value bias based on the observation value calculated by the integer value bias estimation unit 312 and the observation value of the reference station 200 received from the communication unit 308. The positioning execution unit 314 performs positioning based on the integer value bias estimated by the integer value bias estimation unit 312.

<4. Example of operation when mobile station performs interference positioning>
The configuration example of the system of the present embodiment and the receiver 302 of the mobile station 300 has been described above. Hereinafter, an operation example when the mobile station 300 performs interference positioning will be described.

FIG. 6 is a flowchart showing an operation example when the mobile station 300 performs interference positioning. When the mobile station 300 performs interference positioning, the mobile station 300 receives radio waves from the GPS satellite 100 at the GPS receiving unit 304 and acquires observation values (pseudorange and carrier phase) (S102). Next, in S104, the integer value bias estimation unit 312 of the mobile station 300 estimates the integer value bias based on the observed combination of satellites as described above.

The satellite combination used here has m (m−1) / 2 satellite combination candidates when the number of observed satellites is m as described above. When a satellite having a large elevation angle viewed from the mobile station 300 is set as the reference satellite, there are m-1 satellite combination candidates. At this time, the combination of the satellites for which the double difference is calculated is a combination of the reference satellite and the other satellites. The integer value bias estimation unit 312 may estimate the integer value bias using all of these satellite combination candidates, or may estimate the integer value bias using a part of the satellite combinations.

The integer value bias estimation unit 312 receives the observation value of the reference station 200 from the reference station 200, calculates the double difference between the carrier phase and the pseudorange in the above-described satellite combination, and estimates the integer value bias. Next, in S106, the integer value bias estimation unit 312 sends the integer value bias estimated in S104 to the positioning execution unit 314, and the positioning execution unit 314 performs positioning using the received integer value bias.

<5. Example of operation when a mobile station detects a new satellite>
The operation example when the mobile station 300 performs interference positioning has been described above. Hereinafter, an operation example when the mobile station 300 detects a new satellite will be described. As described above, the GPS satellite 100 orbits a predetermined orbit. Therefore, the position of the GPS satellite 100 viewed from the mobile station 300 changes with time. That is, as time passes, the mobile station 300 detects a new satellite.

At this time, if the mobile station 300 again estimates the integer value bias of all the combinations of the satellites using the observation values obtained from the newly detected satellites, the above-described element ratio is significantly lowered. That is, the accuracy of the estimated integer value bias decreases.

In the mobile station 300 according to the embodiment of the present disclosure, in order to prevent the above-described decrease in the accuracy of the integer bias (or the decrease in the element ratio), in parallel with the positioning execution process described in FIG. An integer bias is estimated based on the change in state. That is, the mobile station 300 according to the present embodiment performs positioning using the first integer value bias estimated before the new satellite is detected (the integer value bias estimated in S104 in FIG. 6). In parallel, estimation of a second integer value bias (integer value bias estimated in S210 of FIG. 7 described later) in consideration of a newly detected satellite is performed. FIG. 7 is a flowchart illustrating an example of an operation performed when the mobile station 300 detects a new satellite.

In step S202, the mobile station 300 receives radio waves from the GPS satellite 100 to acquire observation data such as a ranging code and a navigation message. In step S204, the satellite detection unit 306 determines whether a new satellite is detected based on the received observation data. If the satellite detection unit 306 detects a new satellite in S204, the process proceeds to S206. Next, in S206, the integer value bias estimation unit 312 selects a combination of satellites used for estimation of the integer value bias in consideration of the newly detected satellites. At this time, the integer value bias estimation unit 312 estimates the integer value bias using the observed value acquired from the reference station 200 and the observed value observed by the mobile station 300 as described above.

Next, in S208, the integer value bias estimation unit 312 selects a reference satellite from the combination of satellites selected in S206. Here, the reference satellite may be a satellite having the largest elevation angle. Then, the integer value bias estimation unit 312 estimates the integer value bias using the combination of the satellites selected in S206 in parallel with the positioning by the positioning execution unit 314.

Next, in S210, the integer value bias estimation unit 312 determines whether or not the element ratio of the integer value bias estimated in S208 has reached a predetermined standard. When the element ratio of the integer value bias estimated here does not reach the predetermined reference, the integer value bias estimation unit 312 repeatedly performs the estimation of the integer value bias by the least square method.

When it is determined that the element ratio of the integer value bias estimated in S210 has reached a predetermined reference, the integer value bias estimation unit 312 sends the integer value bias that has reached the predetermined reference to the positioning execution unit 314 in S212. . The positioning execution unit 314 calculates the integer bias estimated in consideration of the satellite newly detected in S210 in parallel with the positioning from the positioning using the integer bias estimated before the new satellite is detected. Switch to the positioning you used.

Note that the satellite combination selected in S206 may be the same as or different from the satellite combination used to estimate the integer bias estimated before the new satellite was detected. May be. That is, the combination of the satellites used for estimating the integer value bias used for positioning and the combination of the satellites used for estimating the integer value bias in parallel with the positioning may be the same combination. Different combinations may also be used. At this time, when the reference satellite selected in S208 is different from the reference satellite used for positioning, the combination of these satellites is different. That is, the same satellite is used, but if the reference satellite is different, it is treated as a combination of different satellites. Therefore, the combination of satellites selected in S206 may or may not include a newly detected satellite. This is because the newly detected satellite's elevation angle is still small and the newly detected satellite may not be suitable for use in estimating the integer bias.

As described above, when a new satellite is detected, the mobile station 300 according to the embodiment of the present disclosure estimates a new integer value bias in parallel with the positioning. This also prevents the accuracy of the integer bias from being reduced by immediately adding the newly detected satellite observations and estimating the integer bias. In addition, since the mobile station 300 according to the present embodiment uses the integer value bias for positioning after the integer value bias estimated in parallel with positioning reaches a predetermined reference, the accuracy of the integer value bias is more reliably reduced. Is prevented.

<6. How to select a combination of satellites>
The operation example of the mobile station 300 when a new satellite is detected in the mobile station 300 has been described above. Hereinafter, an example of a selection method for selecting a combination of satellites in the operation example related to FIG. 7 will be described.

The mobile station 300 according to the embodiment of the present disclosure selects a combination of satellites using the position of the GPS satellite 100 and the accuracy degradation (Dilution of Precision, DOP) that is an index of the clock error. The degree of accuracy deterioration is calculated as follows. The variance of the positions of the GPS satellites 100 (the left side of the following equation (7)) is expressed as follows using the geometric matrix G.

Here, σ is the variance of the error in the distance between the mobile station 300 and the satellite.

Here, according to the equation (7), the dispersion of the position of the GPS satellite 100 is divided into a term that depends on the distance error between the mobile station 300 and the satellite and a term that depends on the arrangement of the mobile station 300 and the satellite. Here, assuming that H = (G ^T G) ⁻¹ , the accuracy degradation degree is defined as a term depending on the arrangement of the mobile station 300 and the satellite as follows.

Here, Equation (10) is a position degradation of precision (PDOP) related to the position. In addition, Expression (11) is a time degradation of precision (TDOP). Further, the equation (12) is a geometric accuracy deterioration degree (GDOP).

The accuracy deterioration degree described above is used when a combination of satellites is selected in S206 of FIG. At this time, the combination of satellites is selected so that the degree of accuracy degradation is minimized. The combination of satellites that minimizes the degree of accuracy degradation may be selected so that the degree of accuracy degradation is minimized in the future satellite arrangement. This is because the arrangement of the satellites at the time when the estimation of the integer value bias is completed is taken into consideration. As a result, a combination of satellites with less error is selected, and the mobile station 300 can perform positioning with higher accuracy.

Note that the accuracy deterioration degree used may be any of the position accuracy deterioration degree (PDOP), the time precision deterioration degree (TDOP), and the geometric accuracy deterioration degree (GDOP), and the three accuracy deterioration degrees are combined. And may be used. More preferably, however, the position-related accuracy degradation (PDOP) is used to select the combination of satellites. By calculating the double difference in the process of estimating the integer bias, the satellite and receiver clock errors are eliminated. Therefore, it is preferable to use the degree of accuracy degradation that can obtain information about the position rather than the degree of accuracy degradation (TDOP).

<7. Example of operation when a mobile station detects an unusable satellite>
The operation example when the mobile station 300 detects a new satellite and the accuracy deterioration level used in the operation have been described above. Hereinafter, an operation example of the mobile station 300 when the mobile station 300 detects an unusable satellite will be described. As described above, the GPS satellite 100 orbits a predetermined orbit, and satellites that cannot be used for positioning are generated with time. For example, the elevation angle of the satellite is reduced, and the ionospheric delay and the tropospheric delay are increased, so that the satellite cannot be used for positioning. At this time, the mobile station 300 of the present embodiment calculates an integer value bias excluding satellites that cannot be used in the future in parallel with positioning. FIG. 8 is a flowchart showing an operation example of the mobile station 300 when the mobile station 300 detects an unusable satellite.

First, in S302, the mobile station 300 acquires observation data such as a distance measurement code and a navigation message by receiving radio waves from the GPS satellite 100. In step S304, the satellite detection unit 306 determines whether or not there is a satellite that cannot be used in the future based on the received observation data. In step S <b> 306, the integer value bias estimation unit 312 selects a combination of satellites used for estimation of the integer value bias except for satellites that cannot be used in the future. Here, the determination of the satellite that cannot be used in the future may be performed based on the orbit of the satellite calculated using the ephemeris included in the navigation message.

Further, as in S206 of FIG. 7, when the combination of satellites is selected in S306, the above-described accuracy deterioration degree may be used. At this time, the combination of satellites is selected so that the degree of accuracy degradation is minimized. The combination of satellites that minimizes the degree of accuracy degradation may be selected so that the degree of accuracy degradation is minimized in the future satellite arrangement. This is because the arrangement of satellites at the time when satellites that cannot be used in the future can no longer be used for positioning is taken into consideration. As a result, a combination of satellites with less error is selected, and the mobile station 300 can perform positioning with higher accuracy.

Next, in S308, the integer value bias estimation unit 312 selects a spare reference satellite from the combination of satellites selected in S306. The spare reference satellite may be the satellite having the largest elevation angle. Then, the integer value bias estimation unit 312 estimates the integer value bias using the combination of the satellites selected in S306 in parallel with the positioning by the positioning execution unit 314. Note that the backup reference satellite selected here may be a satellite having the largest elevation angle after a predetermined time has elapsed. This is because the satellite having the largest elevation angle is preferably selected as the reference satellite when the satellite that cannot be used becomes actually unusable for positioning. As a result, since the most appropriate satellite is used as the reference satellite at the time when the unusable satellite is actually unusable, more accurate positioning is performed.

Next, in S310, the satellite detection unit 306 determines whether there is a satellite that has become unusable. If the satellite detection unit 306 determines that there are no satellites that can no longer be used, the integer value bias estimation unit 312 continues to estimate the integer value bias. If the satellite detection unit 306 determines in S310 that there is a disabled satellite, then in S312, the integer value bias estimation unit 312 determines whether the disabled satellite is a reference satellite. Here, the reference satellite in S312 is a reference satellite for estimating the integer value bias used for positioning performed in parallel with the estimation of the integer value bias in S308. Hereinafter, the reference satellite used for this positioning is also referred to as the current reference satellite.

If the integer value bias estimation unit 312 determines in S312 that the satellite that has become unusable is the current reference satellite, the process proceeds to S314. In S314, the integer value bias estimation unit 312 performs integer value bias conversion based on the backup reference satellite selected in S308. The integer value bias conversion performed here will be described below.

Here, r indicates an arbitrary satellite other than the current reference satellite p and the standby reference satellite q used for estimation of the integer value bias.

Returning to the description of the flowchart of FIG. 8, as described above, in S314, the integer value bias estimation unit 312 performs integer value bias conversion based on the standby reference satellite. In S322, the positioning execution unit 314 switches to positioning using the integer value bias replaced in S314.

If the integer value bias estimation unit 312 determines in S312 that the satellite that has become unusable is not the reference satellite, the process proceeds to S316. In S316, the integer value bias estimation unit 312 determines whether or not the reason that the satellite has become unusable is that the elevation angle is equal to or smaller than a predetermined magnitude. If the integer value bias estimation unit 312 determines in S316 that the reason that the satellite has become unusable is a decrease in elevation angle, the process proceeds to S318.

In S318, the integer value bias estimation unit 312 switches the integer value bias used for positioning to the integer value bias estimated in parallel with the positioning in S308. Then, the integer value bias estimation unit 312 sends the integer value bias estimated in parallel with the positioning to the positioning execution unit 314, and the positioning execution unit 314 performs positioning using the integer value bias (S322).

If the integer value bias estimation unit 312 determines in S316 that the reason that the satellite has become unusable is not a decrease in elevation angle, the process proceeds to S320. In S320, the integer value bias estimation unit 312 uses the current reference satellite as a reference for the integer bias estimated in S308 based on the standby reference satellite in the same manner as the replacement of the integer value bias described above using the equation (13). Replace with the integer bias. In S322, the positioning execution unit 314 executes positioning using an integer value bias based on the current reference satellite. As a result, positioning is executed without using the satellite that has become unusable.

As described above, when a satellite that cannot be used in the future is detected, the mobile station 300 according to the embodiment of the present disclosure uses the combination of satellites excluding the satellite that cannot be used to generate a new integer bias. Is estimated. This prevents a decrease in the accuracy of the integer bias due to a change in the satellite state (decrease in the number of satellites). In addition, since a new integer bias is estimated in advance based on a combination of satellites excluding satellites that will become unusable in the future, the mobile station 300 is continuously highly accurate when satellites are actually unusable. Positioning can be performed.

<8. Supplement>
The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. Note that the technical scope of the present disclosure is not limited to such an example. It is obvious that a person having ordinary knowledge in the technical field of the present disclosure can come up with various changes or modifications within the scope of the technical idea described in the claims. Is naturally within the technical scope of the present disclosure.

For example, in the above-described embodiment, the activation of the satellite is estimated by the ephemeris. However, the orbit of the satellite may be estimated by more accurate orbit information. For example, the orbit information may be a super-breaking calendar. In addition, as described in FIG. 8, the mobile station 300 according to the present embodiment immediately performs positioning using a new integer value bias when a satellite becomes unusable. However, even when the satellite becomes unusable, the mobile station 300 does not perform parallel with positioning after the integer value bias estimated in parallel with positioning reaches a predetermined reference as described in FIG. It may be switched to positioning using the integer value bias estimated as described above.

Note that the scope of the present disclosure includes a computer program for operating the receiver 302 as described above. A storage medium storing such a program may be provided.

<9. Conclusion>
As described above, according to the embodiment of the present disclosure, the mobile station 300 estimates the integer value bias in parallel with the positioning. With such a configuration, even when the mobile station 300 detects a new satellite, it is possible to prevent a decrease in the accuracy of the integer value bias. In addition, even when the mobile station 300 detects an unusable satellite, it is possible to prevent a decrease in the accuracy of the integer bias. In addition, when a satellite that cannot be used is detected, positioning can be performed with higher accuracy by changing the processing depending on the attribute of the satellite that cannot be used (for example, whether it is a reference satellite) or the reason (for example, whether it is due to elevation angle reduction) Can be done quickly.

In addition, the effects described in this specification are merely examples and are not limiting. That is, the technology according to the present disclosure can exhibit other effects that are apparent to those skilled in the art from the description of the present specification in addition to or instead of the above effects.

The following configurations also belong to the technical scope of the present disclosure.
(1)
A receiver for receiving radio waves from a satellite;
A detection unit for detecting a satellite based on radio waves from the satellite received by the reception unit;
A positioning unit that estimates an integer value bias using an observation value based on radio waves received from a reference station and the satellite, and performs positioning;
The positioning unit is configured to perform positioning based on a first integer bias determined based on observations of the first combination of satellites, and estimate a second integer bias based on observations of the second combination of satellites. And in parallel,
The positioning unit switches from positioning using the first integer value bias to positioning using the second integer value bias.
(2)
The detection unit according to (1), wherein when the detection unit detects a new satellite, the positioning unit estimates a second integer value bias based on an observation value of the second combination including the new satellite. Positioning device.
(3)
After the second integer value bias reaches a predetermined accuracy, the positioning unit switches from positioning using the first integer value bias to positioning using the second integer value bias. The positioning device according to (1) or (2).
(4)
The positioning device according to any one of (1) to (3), wherein the second combination is selected based on an index of accuracy of the position of the satellite.
(5)
The positioning device according to (4), wherein the second combination is selected so that an index of accuracy of the position of the satellite is minimized.
(6)
The positioning unit predicts an unusable satellite from the first combination based on information from the detection unit,
The positioning unit estimates the second integer value bias based on the observation value of the second combination excluding the satellite that cannot be used,
When the detection unit detects a disabled satellite, the positioning using the first integer value bias is switched to the positioning using the second integer value bias. (1) to (5) The positioning device according to any one of the above.
(7)
When the unusable satellite is a reference satellite, the positioning unit estimates the second integer value bias using another satellite different from the reference satellite as a backup reference satellite,
The positioning device according to (6), wherein the positioning unit performs conversion of an integer value bias using the first integer value bias and the second integer value bias.
(8)
When the unusable satellite becomes unusable due to a decrease in elevation angle, the positioning unit performs positioning by switching from the first integer value bias to the second integer value bias, (6) or The positioning device according to (7).
(9)
A receiver for receiving radio waves from a satellite;
A detection unit for detecting a satellite based on radio waves from the satellite received by the reception unit;
A positioning unit that estimates an integer value bias using an observation value based on radio waves received from a reference station and the satellite, and performs positioning;
The positioning unit is configured to perform positioning based on a first integer bias determined based on observations of the first combination of satellites, and estimate a second integer bias based on observations of the second combination of satellites. And in parallel,
The positioning unit switches from positioning using the first integer value bias to positioning using the second integer value bias.
(10)
Receiving radio waves from satellites,
Detecting satellites based on radio waves received from satellites;
Estimating an integer value bias using observation values based on radio waves received from a reference station and the satellite, and performing positioning;
The positioning based on the first integer bias determined based on the observation value of the first combination of the satellites and the estimation of the second integer bias based on the observation value of the second combination of the satellites are performed in parallel. And doing
Switching from positioning using the first integer value bias to positioning using the second integer value bias.

DESCRIPTION OF SYMBOLS 100 GPS satellite 200

Reference station

202, 302 Receiver 300 Mobile station 304 GPS receiving part 306 Satellite detection part 308 Communication part 310 Positioning part 312 Integer value bias estimation part 314 Positioning execution part 400 Network

Claims

A receiver for receiving radio waves from a satellite;
A detection unit for detecting a satellite based on radio waves from the satellite received by the reception unit;
A positioning unit that estimates an integer value bias using an observation value based on radio waves received from a reference station and the satellite, and performs positioning;
The positioning unit is configured to perform positioning based on a first integer bias determined based on observations of the first combination of satellites, and estimate a second integer bias based on observations of the second combination of satellites. And in parallel,
The positioning unit switches from positioning using the first integer value bias to positioning using the second integer value bias.
The positioning according to claim 1, wherein when the detection unit detects a new satellite, the positioning unit estimates a second integer value bias based on an observation value of the second combination including the new satellite. apparatus.
After the second integer value bias reaches a predetermined accuracy, the positioning unit switches from positioning using the first integer value bias to positioning using the second integer value bias. The positioning device according to claim 2.
The positioning device according to claim 1, wherein the second combination is selected based on an index of accuracy of the position of the satellite.
The positioning device according to claim 4, wherein the second combination is selected such that an index of accuracy of the position of the satellite is minimized.
The positioning unit predicts an unusable satellite from the first combination based on information from the detection unit,
The positioning unit estimates the second integer value bias based on the observation value of the second combination excluding the satellite that cannot be used,
2. The positioning device according to claim 1, wherein when the detection unit detects a disabled satellite, the positioning device switches from positioning using the first integer value bias to positioning using the second integer value bias.
When the unusable satellite is a reference satellite, the positioning unit estimates the second integer value bias using another satellite different from the reference satellite as a backup reference satellite,
The positioning device according to claim 6, wherein the positioning unit performs conversion of integer value bias using the first integer value bias and the second integer value bias.
7. The positioning unit according to claim 6, wherein when the unusable satellite becomes unusable due to a decrease in elevation angle, the positioning unit performs positioning by switching from the first integer value bias to the second integer value bias. 8. Positioning device.
A receiver for receiving radio waves from a satellite;
A detection unit for detecting a satellite based on radio waves from the satellite received by the reception unit;
A positioning unit that estimates an integer value bias using an observation value based on radio waves received from a reference station and the satellite, and performs positioning;
The positioning unit is configured to perform positioning based on a first integer bias determined based on observations of the first combination of satellites, and estimate a second integer bias based on observations of the second combination of satellites. And in parallel,
The positioning unit switches from positioning using the first integer value bias to positioning using the second integer value bias.
Receiving radio waves from satellites,
Detecting satellites based on radio waves received from satellites;
Estimating an integer value bias using observation values based on radio waves received from a reference station and the satellite, and performing positioning;
The positioning based on the first integer bias determined based on the observation value of the first combination of the satellites and the estimation of the second integer bias based on the observation value of the second combination of the satellites are performed in parallel. And doing
Switching from positioning using the first integer value bias to positioning using the second integer value bias.