Positioning device

Abstract

To provide a positioning system capable of performing positioning with high accuracy using a positioning signal without providing reinforcement information together with a positioning signal providing the reinforcement information.SOLUTION: A positioning device 100 includes: a first decode part 21 for detecting a false distance and a carrier wave phase integrated value from a ranging signal L1C / A providing correction reinforcement information [LC / A] and detecting the false distance and the carrier wave phase integrated value from a ranging signal B1C without providing the reinforcement information; an error correction part 27 for detecting the correction data [LC / A] of the ranging signal formed from the reinforcement information to correct the false distance and carrier wave phase integrated value of the ranging signal L1C / A by the correction data [LC / A]; and a positioning calculation part 25 for performing and positioning filter calculation using first and second observation equations obtained by forming the first observation equation using the corrected false distance and carrier wave phase integrated value and forming the second observation equation using the time difference value of the false distance of a ranging signal B1C and the time difference value of the carrier wave phase integrated value.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a positioning device, a positioning program, and a positioning method. [Background technology]

[0002] In satellite positioning, there is a positioning technology that uses positioning augmentation information (hereinafter referred to as augmentation information) to correct errors contained in ranging signals transmitted by positioning satellites and solve the integer bias, which is the uncertainty of the carrier phase integrated value, to obtain a highly accurate positioning solution.Augmentation information, which is error information, is provided as a state quantity for each error factor, and PPP-AR (Precise Point Positioning Ambiguity Resolution) and PPP-RTK (Precise Point Positioning Real-Time Kinematic) are technologies that perform high-precision positioning using augmentation information.

[0003] In the PPP-AR positioning method, the user's positioning device acquires information on the satellite orbit error δO, the satellite clock error δT, and the satellite signal bias B, and corrects the errors contained in the ranging signal. The error information, satellite signal bias B, differs for each signal type, such as L1C / A, L2P, and L2C. Therefore, the satellite signal bias B is provided to the user's positioning device for each signal type, such as L1C / A, L2P, and L2C. In PPP-AR, the tropospheric propagation delay error T and the ionospheric propagation delay error I (hereinafter referred to as the tropospheric delay error T and the ionospheric delay error I) are estimated and removed by model correction or by an estimation filter such as a Kalman filter.

[0004] The PPP-RTK positioning method provides error information on the satellite orbit error δO, satellite clock error δT, satellite signal bias B, as well as the tropospheric delay error T and ionospheric delay error I. The user's positioning device can correct the errors contained in the ranging signal from this error information (δO, δT, B, T, I).

[0005] Furthermore, there is a time differential positioning technique that realizes highly accurate positioning without receiving positioning signals from a plurality of paired positioning satellites (for example, Patent Document 1).

[0006] When using RTK, PPP-AR, and PPP-RTK positioning technologies that can provide highly accurate positioning solutions, the positioning satellites that can be used for precise positioning are limited to those that provide augmentation information. In other words, for positioning satellites that do not provide augmentation information, even if a user's positioning device can acquire ranging signals from positioning satellites that do not provide augmentation information, those ranging signals cannot be used for precise positioning. Therefore, in urban areas where ranging signals are easily blocked by buildings, the number of satellites that can be used for positioning is limited, resulting in a degradation of positioning accuracy. For example, in the centimeter-level positioning augmentation service using quasi-zenith satellites, the augmentation information provided to users is limited to U.S. GPS satellites, European Galileo satellites, and Japanese quasi-zenith satellites. Therefore, augmentation information is not provided for Russia's GLONASS satellites, India's NAVIC satellites, or China's Beidou satellites. Therefore, ranging signals from GLONASS, NAVIC, and Beidou satellites cannot be used for precise positioning.

[0007] Patent Document 1 only discloses a technique for precisely determining the time change of a user's position using time differential positioning, but does not disclose a technique for determining an absolute position. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-45499 Summary of the Invention [Problem to be solved by the invention]

[0009] The present disclosure aims to provide a positioning method that performs highly accurate positioning by using a ranging signal for which no augmentation information is provided together with a ranging signal for which augmentation information is provided, in a precise positioning method that corrects a ranging signal using augmentation information. [Means for solving the problem]

[0010] A positioning device according to the present disclosure includes: an augmentation information receiving unit that receives augmentation information provided to correct errors included in the first ranging signals transmitted from the first positioning satellite and received at multiple times; a decoding unit that decodes the received reinforcement information to generate correction data in which the reinforcement information is decoded, generates observation data of the first ranging signal from the first ranging signal, and generates observation data of the second ranging signal from second ranging signals transmitted by a second positioning satellite and received at multiple times, the second ranging signals not provided with reinforcement information for correcting errors included in the second ranging signals; an error correction unit that corrects an error in the observation data of the first ranging signal based on the correction data decoded from the reinforcement information, and generates the error-corrected observation data of the first ranging signal; a positioning filter that performs a positioning calculation by a least squares method or a filter calculation using the error-corrected observation data of the first ranging signal, time difference data of the observation data of the first ranging signal, and time difference data of the observation data of the second ranging signal; Equipped with. [Effects of the Invention]

[0011] According to the present disclosure, in a precise positioning method that corrects ranging signals using augmentation information, a positioning method can be provided that performs highly accurate positioning by using ranging signals for which augmentation information is not provided together with ranging signals for which augmentation information is provided. This increases the number of ranging signals that can be used for positioning calculations, and can increase the number of satellites that can be used for positioning in urban areas where ranging signals are likely to be blocked by buildings. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 10 is a diagram of the first embodiment, illustrating factors of positioning errors when a ranging signal is used. [Figure 2] FIG. 3 is a diagram of the first embodiment, showing signals transmitted by a GPS satellite 311, a quasi-zenith satellite 312, and a Beidou satellite 313. [Figure 3] FIG. 1 is a diagram of the first embodiment, showing the hardware configuration of a positioning device 100. [Figure 4] FIG. 2 is a diagram of the first embodiment, showing the configuration of a positioning calculation unit 25. [Figure 5] FIG. 10 is a flowchart showing the operation of the positioning calculation unit 25 according to the first embodiment. [Figure 6] FIG. 10 is a diagram of the first embodiment, showing the configuration of a modified example of the positioning calculation unit 25. [Figure 7] 10 is a flowchart showing the operation of a modified example of the positioning calculation unit 25 according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] In the description of the embodiments and drawings, the same elements and corresponding elements are denoted by the same reference numerals. The description of elements denoted by the same reference numerals will be omitted or simplified as appropriate. In the following embodiments, "unit" may be read as "circuit," "step," "procedure," "process," or "circuitry" as appropriate.

[0014] Embodiment 1 The first embodiment will be described with reference to FIGS. FIG. 1 is a diagram for explaining error factors in positioning using a ranging signal such as the L1C / A signal transmitted by a GPS satellite 311. FIG. 2 shows signals transmitted by a GPS satellite 311, a quasi-zenith satellite 312, and a Beidou satellite 313. The GPS satellite 311 transmits a transmission signal 311a. The transmission signal 311a includes an L1C / A signal and an L2C signal as ranging signals. The quasi-zenith satellite 312 transmits a transmission signal 312a. The transmission signal 312a includes the L1C / A signal and the L2C signal, which are ranging signals, and an [L6] signal, which is augmentation information. The [L6] signal, which is augmentation information, is referred to as augmentation information [L6]. The positioning device 100 receives the augmentation information. The augmentation information decoded by the third decoding unit 23 of the positioning device 100 is called correction data. The augmentation information [L6] includes multiple individual augmentation information [i] used for ranging signal i. The individual augmentation information [i] is decoded by the third decoding unit 23 to become correction data. The augmentation information [L6] includes augmentation information [L2C] and augmentation information [L1C / A] between the L1C / A signal and the L2C signal, which are ranging signals transmitted by the GPS satellite 311. The augmentation information [L6] also includes augmentation information [L1C / A] and augmentation information [L2C] between the L1C / A signal and the L2C signal, which are ranging signals transmitted by the quasi-zenith satellite 312. In the following, an example is assumed in which the quasi-zenith satellite 312 transmits an [L6] signal, which is augmentation information. The augmentation information [L6] may be information that conforms to a compressed SSR format (CompactSSR) that supports PPP-RTK, which is capable of centimeter-level positioning, as a state space representation. Note that transmitting the augmentation information as an [L6] signal from the quasi-zenith satellite 312 is just one example. The positioning device 100 does not necessarily need to receive the augmentation information from the quasi-zenith satellite 312, and may receive the augmentation information via the Internet or from a mobile carrier communication network.

[0015] Please refer to Figure 1. Positioning using ranging signals transmitted by positioning satellites of the Global Navigation Satellite System (GNSS), such as GPS satellites 311, quasi-zenith satellites 312, and Beidou satellites 313, involves the following error factors. As shown in Figure 1, the factors that contribute to positioning errors attributable to the satellites include a satellite clock error δT, and errors attributable to the positioning satellites include an orbit error δO and a satellite signal bias B. Errors attributable to the propagation path of the ranging signal include an ionospheric delay error I and a tropospheric delay error T. Errors attributable to the receiving circuit of the positioning device 100 include a receiver clock error and receiver noise. Furthermore, multipath errors caused by interference between ranging signals reflected off buildings and ranging signals received directly from the positioning satellites can also contribute to positioning errors.

[0016] When performing positioning using augmentation information [L6] provided in a state space representation (SSR), errors cannot be corrected for ranging signals i that do not match the individual augmentation information [i] of a given type included in the augmentation information [L6]. This will be explained with reference to FIG. 2. The augmentation information [L6] includes the augmentation information [L1C / A] between the L1C / A signal and the L2C signal, which are ranging signals from GPS satellites 311. The same applies to the quasi-zenith satellite 312. Therefore, ranging signals i transmitted by GPS satellites 311 and quasi-zenith satellites 312 can be corrected using the augmentation information [i] included in the augmentation information [L6]. However, the augmentation information [B1C] and augmentation information [B2a] for the B1C and B2a signals, which are ranging signals from Beidou satellites 313, are not included in the augmentation information [L6]. Therefore, the ranging signals B1C and B2a from Beidou satellites 313 cannot be used for positioning calculations. Therefore, the positioning device 100 provides a mechanism that enables the positioning device 100 to use, for positioning calculation, a ranging signal i from which the positioning device 100 cannot receive augmentation information [i]. This operation will be described in the operation of FIG.

[0017] ***Configuration Description*** Fig. 3 shows the hardware configuration of the positioning device 100. The positioning device 100 will be described with reference to Fig. 3. The positioning device 100 performs positioning using the PPP-RTK positioning method. Note that although the description uses PPP-RTK as an example, other precise positioning methods such as PPP-AR or RTK can also be implemented.

[0018] The positioning device 100 has the following features. When the ranging signal i transmitted from the positioning satellite i does not match the positioning satellite signal type of the individual augmentation information, which is error information such as the "signal bias of pseudorange" or the "signal bias of carrier phase accumulation value" included in the augmentation information [L6], the augmentation information [k] (k≠i) cannot be applied to the ranging signal i. In such a case, the positioning device 100 can use the ranging signal i for which augmentation information [i] is not provided for precise positioning by using the time difference value ΔP of the pseudorange and the time difference value Δφ of the carrier phase accumulation value, as described below.

[0019] 3, the positioning device 100 includes, as hardware, a GNSS receiving unit 10, a processor 20, a main storage device 30, and an auxiliary storage device 40. Each piece of hardware is connected by a signal line 60.

[0020] The GNSS receiver 10 includes an antenna 11, a distributor 12, a ranging signal receiver 13, and an augmentation information receiver 14. The antenna 11 receives transmission signals 311a, 312a, and 313a from a GPS satellite 311, a quasi-zenith satellite 312, and a Beidou satellite 313. The distributor 12 distributes the signals received by the antenna 11 to the ranging signal receiver 13 and the augmentation information receiver 14. The ranging signal receiver 13 transmits the ranging signal, which is one of the signals distributed by the distributor 12, to a first decoder 21 and a second decoder 22. The ranging signal receiver 13 transmits a carrier phase integrated value φ, a pseudorange P, and a Doppler D to the first decoder 21, and transmits a navigation message to the second decoder 22. The supplemental information receiving unit 14 transmits the supplemental information [L6] from the signals distributed by the distributor 12 to the third decoding unit 23.

[0021] The processor 20 includes a first decoding unit 21, a second decoding unit 22, a third decoding unit 23, a satellite calculation unit 24, and a positioning calculation unit 25. The first decoding unit 21, the second decoding unit 22, and the third decoding unit 23 constitute a decoding unit 70. These functional units are implemented by a positioning program 101. The positioning program 101 is stored in the auxiliary storage device 40. The positioning program 101 is a program that causes a computer to execute each process, procedure, or step of the first decoding unit 21, the second decoding unit 22, the third decoding unit 23, the satellite calculation unit 24, and the positioning calculation unit 25, where the "unit" is replaced with "process," "procedure," or "step." The positioning method is performed by the positioning device 100, which is a computer, executing the positioning program 101. In other words, the positioning method is executed by the positioning device 100, which is a computer. The positioning program 101 may be provided in a state stored in a computer-readable recording medium, or may be provided as a program product.

[0022] 4, the positioning calculation unit 25 includes a positioning filter 26, an error correction unit 27, and a time difference calculation unit 28. As will be described later with reference to FIG. 5, the positioning calculation unit 25 may further include a drift correction unit 29.

[0023] The GNSS receiver 10 receives transmission signals from positioning satellites. The transmission signal 311a from the GPS satellite 311 and the transmission signal 313a from the Beidou satellite 313 include a navigation message and a ranging signal. The transmission signal 312a from the quasi-zenith satellite 312 includes augmentation information [L6] in addition to the navigation message and ranging signal. The ranging signal transmitted by each positioning satellite includes a carrier phase integrated value φ, a pseudorange P, and a Doppler D.

[0024] Pseudorange of the positioning satellite SAT at time tk corrected by the augmentation information [L6]<P(tk)> The observation equation for is expressed as follows (Equation 1). <P(tk)> =ρ(tk)+c×δt(tk)+εp(tk) (Equation 1) In (Equation 1), ρ(tk) is the geometric distance between the positioning device 100 and the positioning satellite SAT, c is the speed of light, δt(tk) is the clock error of the positioning device 100, and εp(tk) is the observation noise error. By calculating the inter-satellite difference <△Pab(tk)> between the pseudo-range <Pa(tk)> of the positioning satellite SATa corrected by the augmentation signal [L6] and the pseudo-range <Pb(tk)> of the positioning satellite SATb corrected by the augmentation signal [L6], the clock error of the positioning device 100 may be canceled out as represented by (Equation 2). <△Pab(tk)> = <Pa(tk)> - <Pb(tk)> = ρa(tk) - ρb(tk) + εpa(tk) - εpb(tk) (Equation 2)

[0025] The observation equation for the carrier phase integral value <φ(tk)> of the positioning satellite SAT at time tk corrected by the augmentation information [L6] is represented by the following (Equation 3). <φ(tk)> = ρ(tk) + c×δt(tk) + λ×N(tk) + εφ(tk) (Equation 3) In (Equation 3), ρ(tk) is the geometric distance between the positioning device 100 and the positioning satellite SAT, c is the speed of light, δt(tk) is the clock error of the positioning device 100, and εφ(tk) is the observation noise error. By calculating the inter-satellite difference <△φab(tk)> between the carrier phase integral value <φa(tk)> of the positioning satellite SATa corrected by the augmentation signal [L6] and the carrier phase integral value <φb(tk)> of the positioning satellite SATb corrected by the augmentation signal [L6], the clock error of the positioning device 100 may be canceled out as represented by (Equation 2). <△φab(tk)> = <φa(tk)> - <φb(tk)> = ρa(tk) - ρb(tk) + εpa(tk) - εpb(tk) (Equation 4)

[0026] The following shows the observation equations for the time difference △P of the pseudo-range P and the time difference △φ of the carrier phase integral value φ.

[0027] <A. Observation Model of Pseudo-Range> The observation equation for the pseudo-range P(tk) at time tk is expressed by the following (Equation 5). This observation equation is defined individually for each signal of the positioning satellite SAT. P(tk)=ρ(tk)+δO(tk)+c×δt(tk)-c×δT(tk)+I(tk)+T(tk)+Bp(tk)+εp(tk) (Equation 5) In (Equation 5), the meanings of the respective symbols are as follows. ρ(tk) is the geometric distance between the positioning device 100 and the positioning satellite SAT. δO(tk) is the orbit error of the positioning satellite SAT. c is the speed of light, δt(tk) is the clock error of the positioning device 100. δT(tk) is the clock error of the positioning satellite SAT. I(tk) is the ionospheric delay error. T(tk) is the tropospheric delay error. Bp(tk) is the code bias error of the positioning device 100 and the positioning satellite SAT. εp(tk) is the observation noise error.

[0028] <B. Observation Model of Carrier Phase Integration Value> Also, the observation equation for the carrier phase integration value φ(tk) at time tk is expressed by the following (Equation 6). This observation equation is defined individually for each signal of the positioning satellite SAT. φ(tk)=ρ(tk)+δO(tk)+c×δt(tk)-c×δT(tk)-I(tk)+T(tk)+Bφ(tk)+λ×N(tk)+εφ(tk) (Equation 6) In (Equation 6), ρ(tk) is the geometric distance between the positioning device 100 and the positioning satellite SAT. δO(tk) is the orbit error of the positioning satellite SAT, c is the speed of light, δt(tk) is the clock error of the positioning device 100, δT(tk) is the clock error of the positioning satellite SAT, I(tk) is the ionospheric delay error, T(tk) is the tropospheric delay error, Bφ(tk) is the carrier phase integration value bias error of the positioning device 100 and the positioning satellite SAT, λ is the wavelength of the carrier phase, N(tk) is the ambiguity, and εφ(tk) is the observation noise error.

[0029] <C. Equation for the time difference value △P of the pseudo-range> When the difference between time tk-1 and time tk is sufficiently small, the time difference △P(tk-1, tk) between the pseudo-range at time tk-1 and the pseudo-range at time tk can be approximated as follows in the following (Equation 7). Note that the clock error δT of the positioning satellite SAT in (Equation 5) is corrected from the navigation message. △P(tk-1, tk)=P(tk)-P(tk-1)= ρ(tk)-ρ(tk-1)+εp(tk)-εp(tk-1) (Equation 7) When the frequency stability of the positioning device 100 is low, the time difference c×δt(tk)-c×δt(tk-1) of the clock error of the positioning device 100 cannot be canceled out. Therefore, by calculating the inter-satellite difference △▽Pab(tk-1, tk) between the time difference △Pa(tk-1, tk) of the positioning satellite SATa and the time difference △Pb(tk-1, tk) of the positioning satellite SATb, the clock error of the positioning device 100 can be completely canceled out. △▽Pab can be calculated from (Equation 8). △▽Pab(tk-1, tk)=△Pa-△Pb=ρa(tk)-ρa(tk-1)-ρb(tk)+ρb(tk-1)+εpa(tk)-εpa(tk-1)-εpb(tk)+εpb(tk-1) (Equation 8)

[0030] <D. Equation for the time difference value △φ of the carrier phase integration value> When the difference between time \(t_{k - 1}\) and time \(t_{k}\) is sufficiently small and no cycle slip occurs between time \(t_{k - 1}\) and time \(t_{k}\), the time difference \(\Delta\varphi(t_{k - 1},t_{k})\) between the carrier phase integration value at time \(t_{k - 1}\) and the carrier phase integration value at time \(t_{k}\) can be approximated as in the following (Equation 9). Note that the clock error \(\delta T\) of the positioning satellite SAT in (Equation 6) is corrected using the navigation message. \(\Delta\varphi(t_{k - 1},t_{k})=\varphi(t_{k})-\varphi(t_{k - 1})=\) \(\rho(t_{k})-\rho(t_{k - 1})+\varepsilon_{p}(t_{k})-\varepsilon_{p}(t_{k - 1})\) (Equation 9) When the frequency stability of the positioning device 100 is low, since the time difference \(c\times\delta t(t_{k})-c\times\delta t(t_{k - 1})\) of the clock error of the positioning device 100 cannot be canceled out, by calculating the inter-satellite difference \(\Delta\nabla\varphi_{ab}(t_{k - 1},t_{k})\) between the time difference \(\Delta\varphi_{a}(t_{k - 1},t_{k})\) of the positioning satellite SATa and the time difference \(\Delta\varphi_{ab}(t_{k - 1},t_{k})\) of the positioning satellite SATb, the clock error of the positioning device 100 can be completely canceled out. \(\Delta\nabla\varphi_{ab}(t_{k - 1},t_{k})\) can be calculated from (Equation 10). \(\Delta\nabla\varphi_{ab}(t_{k - 1},t_{k})=\Delta\varphi_{a}-\Delta\varphi_{b}=\rho_{a}(t_{k})-\rho_{a}(t_{k - 1})-\rho_{b}(t_{k})+\rho_{b}(t_{k - 1})+\varepsilon_{\varphi a}(t_{k})-\varepsilon_{\varphi a}(t_{k - 1})-\varepsilon_{\varphi b}(t_{k})+\varepsilon_{\varphi b}(t_{k - 1})\) (Equation 10)

[0031] <F. Calculation of User Position> \(\rho(t_{k})\) is a function of the user position \(u(t_{k})\) at time \(t_{k}\), and \(\rho(t_{k - 1})\) is a function of the user position \(u(t_{k - 1})\) at time \(t_{k - 1}\). Considering that \(u(t_{k - 1})\) is known, from the simultaneous equations of (Equation 2), (Equation 4), (Equation 7), and (Equation 9), using the least squares method or the Kalman filter, the user position \(u(t_{k})\) at time \(t_{k}\) and the ambiguity \(N(t_{k})\) at time \(t_{k}\) are calculated. Since (Equation 7) and (Equation 9) can be constructed for ranging signals that do not match the reinforcement information [L6], the user position can be calculated using more ranging signals.

[0032] From the simultaneous equations of (Equation 2), (Equation 4), (Equation 8), and (Equation 10), by using the least squares method or the Kalman filter, the clock error of the positioning device 100 can be completely canceled out, and a more accurate user position can be obtained.

[0033] <G. Drift Correction of Pseudo-Distance> When the difference between time tk-1 and time tk is large, or when positioning is performed over a long period of time using only time-difference positioning, as shown in (Equation 11), the drift error bp(tk, tk-1), which is an error that occurs in the time-difference value and varies with time, cannot be ignored, and the approximations in (Equation 7) and (Equation 9) do not hold. Note that the drift error bp(tk-1, tk) of the pseudo-distance error is defined individually for the signals of the positioning satellites SAT. △P(tk-1, tk)=P(tk)-P(tk-1)=ρ(tk)-ρ(tk-1)+c×δt(tk)-c×δt(tk-1)+bp(tk-1, tk)+εp(tk)-εp(tk-1) (Equation 11) bp(tk-1, tk) may be approximated by a linear expression of time using the coefficient kp as shown in (Equation 12). bp(tk-1, tk)=kp×(tk-tk-1) (Equation 12) By estimating the coefficient kp of the drift error in advance, when performing time-difference positioning, the drift error bp(tk-1, tk) in (Equation 11) can be removed. bp(tk-1, tk) is not limited to a linear expression of time and may be a polynomial of time. The time-difference value c×δt(tk)-c×δt(tk-1) of the clock error of the positioning device 100 may be canceled out by taking the satellite-to-satellite single difference with respect to (Equation 11) in the same manner as (Equation 8) described above. △▽Pab(tk-1, tk)=△Pa-△Pb=ρa(tk)-ρa(tk-1)-ρb(tk)+ρb(tk-1)+kpa×(tk-tk-1)-kpb×(tk-tk-1)+εpa(tk)-εpa(tk-1)-εpb(tk)+εpb(tk-1) (Equation 13) In (Equation 13), kpa is the coefficient of the drift error of the pseudo-distance of the positioning satellite SATa, and kpb is the coefficient of the drift error of the pseudo-distance of the positioning satellite SATb.

[0034] <H. Drift Correction of Carrier Phase Integration Value> Similar to the drift correction of the pseudo range, the observation equation of the carrier phase integration value considering the drift error bφ(tk-1, tk) of the carrier phase integration value is shown in the following (Equation 14). △φ(tk-1, tk)=φ(tk)-φ(tk-1)=ρ(tk)-ρ(tk-1)+c×δt(tk)-c×δt(tk-1)+bφ(tk-1, tk)+εp(tk)-εp(tk-1) (Equation 14) bφ(tk-1, tk) may be approximated by a linear expression of time as in (Equation 12). bφ(tk-1, tk)=kφ×(tk-tk-1) (Equation 15) By pre-estimating the coefficient kφ of the drift error of the carrier phase integration value, the drift error bφ(tk-1, tk) in (Equation 14) can be removed. bφ(tk-1, tk) may be not limited to a linear expression of time but a polynomial of time. The time difference value c×δt(tk)-c×δt(tk-1) of the clock error of the positioning device 100 may be offset by taking the inter-satellite single difference with respect to (Equation 14) as in the above (Equation 10). △▽φab(tk-1, tk)=△φa-△φb=ρa(tk)-ρa(tk-1)-ρb(tk)+ρb(tk-1)+kφa×(tk-tk-1)-kφb×(tk-tk-1)+εφa(tk)-εφa(tk-1)-εφb(tk)+εφb(tk-1) (Equation 16) In (Equation 16), kφa is the coefficient of the drift error of the carrier phase integration value of the positioning satellite SATa, and kφb is the coefficient of the drift error of the carrier phase integration value of the positioning satellite SATb.

[0035] <I. Calculation of User Position by Drift Correction> When the coefficient kp of the drift error of the pseudo range error and the coefficient kφ of the drift error of the carrier phase integration value are obtained in advance, based on the simultaneous equations of (Equation 2), (Equation 4), (Equation 13), and (Equation 16), by constructing the least squares method or the Kalman filter, the user position can be obtained with high precision even when the difference between the time tk-1 and the time tk is large.

[0036] <Estimation of J. Drift Error> The coefficients kp of the drift error of the pseudo-range error and kφ of the drift error of the carrier phase integration value are estimated by the following procedure during a time period when a ranging signal that matches the augmentation information [L6] such as an open sky environment can be sufficiently secured. The user positions u(tk-1) at time k-1 and u(tk) at time k are obtained by the least squares method or the Kalman filter based on the simultaneous equations of (Equation 2) and (Equation 4). Next, by substituting the obtained user positions u(tk-1) and u(tk) into (Equation 13) and (Equation 16), the geometric distances ρa(tk), ρa(tk-1), ρb(tk), and ρb(tk-1) are obtained. At this point, the unknowns in (Equation 13) and (Equation 16) are kpa, kpb, kφa, and kφb. By using the least squares method or the Kalman filter based on the simultaneous equations of (Equation 13) and (Equation 16), kpa, kpb, kφa, and kφb can be estimated.

[0037] ***Description of Operation*** In the following, it is assumed that the ranging signal is the L1C / A signal of GPS satellite 311 and the B1C signal of Beidou satellite 313, and the augmentation information is the [L6] signal of the quasi-zenith satellite 312.

[0038] <Time tk-1 and Time tk of GPS Satellite 311> At time \(t_{k - 1}\), the GPS satellite 311 transmits a transmission signal 311a including the L1C / A signal. In FIG. 3, the transmission signal 311a is received by the antenna 11, and is signal-processed by the ranging signal receiving unit 13 via the distributor 12. Observation data is generated from the signal-processed transmission signal 311a by the first decoding unit 21. The observation data is stored in the ranging signal table 31 of the main storage device 30. Also, a navigation message is generated from the signal-processed transmission signal 311a by the second decoding unit 22. The generated navigation message is passed to the satellite calculation unit 24. The satellite calculation unit 24 passes the satellite position and the satellite time to the positioning calculation unit 25. Similarly, at time \(t_{k}\), observation data is generated by the first decoding unit 21, and the observation data is stored in the ranging signal table 31 of the main storage device 30. The processing of the second decoding unit 22 and the third decoding unit 23 at time \(t_{k}\) is also the same as the processing of the second decoding unit 22 and the third decoding unit 23 at time \(t_{k - 1}\).

[0039] As shown in FIG. 2, until time \(t_{k}\), the quasi-zenith satellite 312 transmits a transmission signal 312a including not only the L1C / A signal but also the reinforcement information [L6]. The reinforcement information [L6] includes the reinforcement information [L1C / A], [L2C] of the GPS satellite 311 and the reinforcement information [L1C / A], [L2C] of the quasi-zenith satellite 312. However, the reinforcement information [L6] does not include the reinforcement information of the ranging signals B1C and B2a of the Beidou satellite 313. The reinforcement information [L6] included in the transmission signal 312a of the quasi-zenith satellite 312 is received by the antenna 11, and is signal-processed by the reinforcement information receiving unit 14 via the distributor 12. The reinforcement information [L6] signal-processed by the reinforcement information receiving unit 14 is generated as correction data [L6] by the third decoding unit 23 and is passed to the positioning calculation unit 25. Here, this "correction data" is the correction data [L1C / A] for correcting the ranging signal L1C / A signal for the ranging signal L1C / A signal of the GPS satellite 311. The correction data is transmitted to the positioning calculation unit 25, for example, at a continuous 30-second cycle.

[0040] <The time \(t_{k - 1}\) and time \(t_{k}\) of the Beidou satellite 313> At time tk-1, the Beidou satellite 313 transmits a transmission signal 313a including a B1C signal. The transmission signal 313a is received by the antenna 11, passes through the distributor 12, and is processed by the ranging signal receiver 13. The first decoder 21 generates observation data from the processed transmission signal 313a. This observation data is stored in the ranging signal table 31 in the main storage device 30. The second decoder 22 generates a navigation message from the processed transmission signal 313a and passes it to the satellite calculation unit 24. The satellite calculation unit 24 passes the satellite position and satellite time to the positioning calculation unit 25. Similarly, at time tk, the first decoder 21 generates observation data, which is stored in the ranging signal table 31 in the main storage device 30. The operations of the second decoder 22 and the third decoder 23 at time tk are the same as those at time tk-1.

[0041] <Step S11> 4 shows the configuration of the positioning calculation unit 25. The positioning calculation unit 25 includes a positioning filter 26, an error correction unit 27, and a time difference calculation unit . The decoding unit 70 decodes the reinforcement information at multiple times to generate corrected data in which the reinforcement information is decoded, decodes the first ranging signal in which the reinforcement information is provided to generate observation data of the first ranging signal, and decodes the second ranging signal in which the reinforcement information is not provided to generate observation data of the second ranging signal. The error correction unit 27 corrects errors in the observation data of the first ranging signal based on the correction data. The positioning filter 26 performs positioning calculations using the observation data of the first ranging signal whose errors have been corrected by the error correction unit 27, the time difference data of the observation data of the first ranging signal, and the time difference data of the observation data of the second ranging signal. As will be described later, the time difference data is calculated by the time difference calculation unit 28. This will be explained in detail below.

[0042] Fig. 5 is a flowchart showing the operation of the positioning calculation unit 25 in Fig. 4. The operation of the positioning calculation unit 25 will be described with reference to Figs.

[0043] <Step S11> In step S11, the positioning calculation unit 25 receives, from the ranging signal table 31, the L1C / A(tk-1) signal at time tk-1 of the GPS satellite 311, which is a satellite to be augmented, and the L1C / A(tk) signal at time tk of the GPS satellite 311. The term "satellite to be augmented" means that the positioning device 100 can receive the ranging signal i and augmentation information [i] of that positioning satellite, and that the positioning device 100 can correct errors in the ranging signal i using the augmentation information [i]. Similarly, the positioning calculation unit 25 receives, from the ranging signal table 31, the B1C(tk-1) signal at time tk-1 of the Beidou satellite 313, which is a satellite not to be augmented, and the B1C(tk) signal at time tk of the Beidou satellite 313, at time tk. A "non-augmented satellite" refers to a positioning satellite for which the positioning device 100 cannot correct the error in the ranging signal i using the augmentation information [i] because the positioning device 100 cannot receive the augmentation information [i] of the ranging signal i of that positioning satellite. Here, the information acquired from the ranging signal table 31 is as follows. The first decoding unit 21, which is a detection unit, detects a first pseudorange P1 and a first carrier phase integrated value φ1 from the first ranging signal, which is a ranging signal of a first positioning satellite received at multiple times and to which augmentation information for correction is provided. Here, the first positioning satellite is a GPS satellite 311. The first ranging signal is an L1C / A signal. The augmentation information of the L1C / A signal is augmentation information [L1C / A]. The first decoding unit 21 also detects a second pseudorange P2 and a second carrier phase integrated value φ2 from a second ranging signal received at multiple times from a second positioning satellite, the second ranging signal being a ranging signal without augmentation information for correction. Here, the second positioning satellite is the Beidou satellite 313. The second ranging signal is a B1C signal. The B1C signal does not include augmentation information. From the ranging signal table 31, the positioning calculation unit 25 obtains the first pseudo-range P1 and the first carrier wave phase integrated value φ1, and the second pseudo-range P2 and the second carrier wave phase integrated value φ2. The process from step S11 onwards is outlined as follows: The positioning calculation unit 25 generates a first observation equation for the GPS satellite 311, which is the first positioning satellite, using the first pseudorange P1 corrected by the augmentation information and the first carrier phase accumulated value φ1 corrected by the augmentation information. The positioning calculation unit 25 also generates a second observation equation for the Beidou satellite 313, which is the second positioning satellite, using the time difference value ΔP2 of the second pseudorange P2 and the time difference value Δφ2 of the second carrier phase accumulated value φ2. The positioning calculation unit 25 performs positioning by executing a filter calculation using the first observation equation and the second observation equation in the positioning filter 26. The positioning calculation unit 25 outputs the calculation result as a position estimation result 25A.

[0044] <Step S12> The error correction unit 27 corrects the L1C / A(tk) signal of the GPS satellite 311 at time tk using the correction data [L1C / A] transmitted from the third decoding unit 23, thereby obtaining a corrected L1C / A signal. <l1c a>Generate a signal. <l1c a>The signal is input by the error correction unit 27 to the Kalman filter, which is the positioning filter 26 . Specifically, it is as follows: In the positioning calculation unit 25, the error correction unit 27 acquires correction data [L1C / A] of the L1C / A signal generated from the augmentation information [L1C / A] provided to the L1C / A signal of the GPS satellite 311, which is the first ranging signal, and the first pseudorange P1 and first carrier phase accumulated value φ1 detected by the first decoding unit 21, which is the detection unit. The first pseudorange P1 is the pseudorange of the L1C / A signal, and the first carrier phase accumulated value φ1 is the carrier phase accumulated value of the L1C / A signal. The error correction unit 27 corrects the first pseudorange P1 and the first carrier phase accumulated value φ1 using the correction data [L1C / A]. The error correction unit 27 inputs the corrected first pseudorange P1 and first carrier phase accumulated value φ1 to the positioning filter 26. As described in step S15, the positioning calculation unit 25 generates a first observation equation using the first pseudorange P1 and the first carrier phase accumulated value φ1 corrected by the error correction unit 27, and performs a filter calculation.

[0045] <Step S13> The time difference calculation unit 28 receives the L1C / A(tk-1) signal of the GPS satellite 311 at time tk-1, the L1C / A(tk) signal of the GPS satellite 311 at time tk, the B1C(tk-1) signal of the Beidou satellite 313 at time tk-1, and the B1C(tk) signal of the Beidou satellite 313 at time tk.

[0046] <Step S14> The time difference calculation unit 28 calculates the time difference value of the distance measurement signal at times tk and tk-1. That is, the time difference calculation unit 28 calculates the time difference value ΔP(tk-1, tk) and the time difference value Δφ(tk-1, tk) of the pseudorange and the carrier phase integrated value at times tk and tk-1. The time difference calculation unit 28 inputs the calculated ΔP(tk-1, tk) and Δφ(tk-1, tk) to the positioning filter 26.

[0047] <Step S15> The positioning filter 26 uses the input signal 12 <l1c a>In step S14, a positioning calculation is performed based on ΔP(tk-1, tk) and Δφ(tk-1, tk) inputted, and the position estimate 25a of the positioning device 100 at time tk is outputted.

[0048] <Modification> FIG. 6 shows a modified example in which the positioning calculation unit 25 has a drift correction unit 29 . FIG. 7 shows a flowchart of the operation of the positioning calculation unit 25 having the drift correction unit 29. The flowchart in FIG. 7 differs from the flowchart in FIG. 5 in steps S14a, S14b, and S15a. Only the different steps will be explained. Note that step S14a corresponds to step S14, and step S15a corresponds to step S15. Step S14b is unique to the flowchart in FIG. 7.

[0049] <Step S14a> In step S14a, the time difference calculation unit 28 outputs the calculated ΔP(tk−1, tk) and Δφ(tk−1, tk) to the drift correction unit 29.

[0050] <Step 14b> In step S14b, the drift correction unit 29 estimates drift errors using the positioning solutions obtained by the positioning filter 26 and ΔP(tk-1, tk) and Δφ(tk-1, tk) calculated in step S14a, and corrects the drift errors of ΔP(tk-1, tk) and Δφ(tk-1, tk). The drift correction unit 29 outputs ΔP(tk-1, tk) with the drift errors corrected and Δφ(tk-1, tk) with the drift errors corrected to the positioning filter 26. Specifically, it is as follows: The drift correction unit 29 corrects the drift error, which is an error that occurs in each of the time difference values ​​among the time difference value △P1 of the first pseudo distance P1, which is the pseudo distance of the L1C / A signal, the time difference value △φ1 of the first carrier phase accumulation value φ1, which is the carrier phase accumulation value of the L1C / A signal, the time difference value △P2 of the second pseudo distance P2, which is the pseudo distance of the B1C signal, and the time difference value △φ2 of the second carrier phase accumulation value φ2, which is the carrier phase accumulation value of the B1C signal, and which is an error that fluctuates over time, for each time difference value. The positioning calculation unit 25 uses the respective time difference values ​​whose drift errors have been corrected by the drift correction unit 29 to generate a third observation equation for the L1C / A signal, i.e., for the GPS satellite 311 that transmits the L1C / A signal, and generates a second observation equation for the B1C signal, i.e., for the Beidou satellite 313 that transmits the B1C signal. As described above, the drift correction unit 29 corrects the drift error for each time difference value using the positioning solution, which is the result of the filter calculation performed by the positioning filter 26.

[0051] <Step 15a> In step S15a, the positioning filter 26 receives the signal input in step S12. <l1c a>A positioning calculation is performed based on △P(tk-1, tk) and △φ(tk-1, tk) after the drift error correction input in step S14b, and the position estimate value 25a of the positioning device 100 at time tk is output.

[0052] ***Explanation of the effect of the first embodiment*** According to the positioning device 100 of the first embodiment, in addition to using the pseudorange and carrier phase integrated value corrected by the correction data for the "reinforcement target satellite," the positioning device 100 uses the time difference value of the pseudorange and the time difference value of the carrier phase integrated value for the "non-reinforcement target satellite." This allows precise positioning to be performed by using the ranging signal i for which the reinforcement information [i] cannot be received together with the ranging signal k for which the reinforcement information [k] can be received. Furthermore, since ΔP(tk-1, tk) and Δφ(tk-1, tk) whose drift errors have been corrected by the drift corrector 29 are used, the positioning accuracy can be improved. [Explanation of symbols]

[0053] δt satellite clock error, δO satellite orbit error, B satellite signal bias, I ionospheric error, T tropospheric delay error, P pseudorange, φ carrier phase integrated value, 10 GNSS receiver, 11 antenna, 12 distributor, 13 ranging signal receiver, 14 augmentation information receiver, 20 processor, 21 first decoder, 22 second decoder, 23 third decoder, 24 satellite calculation unit, 25 positioning calculation unit, 25a position estimate, 26 positioning filter, 27 error correction unit, 28 time difference calculation unit, 29 drift correction unit, 30 main memory device, 31 ranging signal table, 40 auxiliary memory device, 60 signal line, 70 decoder, 100 positioning device, 311 GPS satellite, 311a transmission signal, 312 quasi-zenith satellite, 312a transmission signal, 313 Beidou satellite, 313a transmitted signal.

Claims

1. an augmentation information receiving unit that receives augmentation information provided to correct errors included in the first ranging signals transmitted from the first positioning satellite and received at a plurality of times; a decoding unit that decodes the received reinforcement information to generate correction data in which the reinforcement information is decoded, generates observation data of the first ranging signal from the first ranging signal, and generates observation data of the second ranging signal from second ranging signals transmitted by a second positioning satellite and received at multiple times, the second ranging signals not being provided with reinforcement information for correcting errors included in the second ranging signals; an error correction unit that corrects an error in the observation data of the first ranging signal based on the correction data decoded from the reinforcement information, and generates the error-corrected observation data of the first ranging signal; a positioning filter that performs a positioning calculation by a least squares method or a filter calculation using the error-corrected observation data of the first ranging signal, time difference data of the observation data of the first ranging signal, and time difference data of the observation data of the second ranging signal; A positioning device comprising:

2. The first positioning satellite is The positioning device of claim 1 , wherein both the first ranging signal and the augmentation information are transmitted to correct an error contained in the first ranging signal.

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