Rapid recapture positioning method and device after loss of lock of satellite navigation receiver

Abstract

The invention provides a method and a device for quickly recapturing and positioning a satellite navigation receiver after loss of lock, and the method comprises the steps: after the receiver is lost of lock, obtaining a plurality of target satellites according to the loss of lock duration, the ephemeris at the latest moment before the loss of lock, the Doppler value at the latest moment before the loss of lock and the receiver position information at the latest moment before the loss of lock; the method comprises the following steps: calculating elevation values at the latest moment before lock losing and maximum allowable lock losing time corresponding to a plurality of target satellites, and calculating pseudo-range values of the target satellites after judging whether the elevation values at the latest moment before lock losing are greater than an elevation threshold and whether the lock losing duration is less than the maximum allowable lock losing time in sequence; and traversing the target satellites until the number of the obtained target satellites with the pseudo-range value meets a preset requirement, and then carrying out positioning calculation. According to the scheme, the problem of rapid recapture positioning after the receiver loses lock is solved, the time for using the rapid recapture positioning method is effectively prolonged, and the recapture positioning capability when the receiver loses lock for a long time is greatly improved. The method has more obvious advantages for a high-speed moving carrier.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of satellite navigation technology, in particular, to a satellite navigation receiver fast reacquisition positioning method and device after losing lock. BACKGROUND

[0002] Global Navigation Satellite System (GNSS) can provide users with all-weather, continuous, accurate position, speed and time information in the global range. The application of this system has penetrated into many aspects of economy, society and military. At present, there are four major global satellite navigation systems in space, namely, China's BeiDou, America's GPS, Russia's GLONASS and the European Union's Galileo.

[0003] The satellite navigation receiver is used to receive the satellite navigation system signal to realize the positioning and timing function. Due to factors such as shielding, interference or carrier attitude change, the satellite navigation receiver may not be able to continuously track the satellite navigation signal and maintain continuous positioning calculation. When this situation occurs, the user needs to quickly recover the positioning. The traditional lost lock reacquisition positioning method is similar to the cold start process, which needs to wait for the frame synchronization to be completed to obtain the pseudo-range value, and then to perform the positioning calculation. The disadvantage of this method is that the frame synchronization process takes a long time, resulting in the lost lock reacquisition time exceeding 6s, which cannot meet the use requirements of high-speed moving carriers. There are also documents that improve the traditional method by omitting the frame synchronization process, effectively shortening the lost lock reacquisition time, but still have the following problems: (1) the entire navigation system satellites are captured after losing lock, which is low in efficiency, especially when the satellite signal is weak and the capture detection probability is low; (2) only according to the maximum flight speed of the carrier to set the effective time of the fast reacquisition positioning method, which cannot perform fast reacquisition positioning for long-time lost lock scenarios. SUMMARY

[0004] In view of the defects in the prior art, the purpose of the present application is to provide a satellite navigation receiver fast reacquisition positioning method and device after losing lock, which solves the problem of fast reacquisition positioning after the receiver loses lock, and effectively prolongs the time when the fast reacquisition positioning method can be used, greatly improves the reacquisition positioning capability of the receiver when losing lock for a long time. For high-speed moving carriers, this method has more obvious advantages.

[0005] The present application provides a satellite navigation receiver fast reacquisition positioning method after losing lock, which comprises: acquiring the state information of the satellite navigation receiver; In a case where the state information of the satellite navigation receiver indicates that the satellite navigation receiver is lost, a lock loss duration, latest pre-lock time ephemeris corresponding to a plurality of target satellites, latest pre-lock time Doppler values, and latest pre-lock time receiver position information of the satellite navigation receiver are acquired; a time corresponding to a latest pre-lock time record is defined as a latest pre-lock time; Based on the latest pre-lock time ephemeris and the latest pre-lock time receiver position information, latest pre-lock time elevation values corresponding to the plurality of target satellites are calculated; and based on the latest pre-lock time Doppler values, maximum allowed lock loss times corresponding to the plurality of target satellites are calculated. One of the target satellites is selected as a current satellite; It is determined whether the latest pre-lock time elevation value corresponding to the current satellite is greater than an elevation threshold; In a case where the latest pre-lock time elevation value corresponding to the current satellite is greater than the elevation threshold, it is determined whether the lock loss duration is less than the maximum allowed lock loss time corresponding to the current satellite; In a case where the lock loss duration is less than the maximum allowed lock loss time corresponding to the current satellite, a pseudo-range value of the current satellite is calculated after the current satellite is stably tracked; The target satellites are iterated until a quantity of the target satellites for which the pseudo-range value is acquired satisfies a preset requirement, and positioning calculation is performed.

[0006] Further, the determination of the pseudo-range value of the current satellite after the current satellite is stably tracked specifically includes: Based on a latest pre-lock time signal transmission time value corresponding to the current satellite and the lock loss duration, a current TIC signal transmission time coarse value of the current satellite is calculated; the latest pre-lock time signal transmission time value is acquired when it is determined that the satellite navigation receiver is lost; The current TIC signal transmission time coarse value corresponding to the current satellite is corrected according to a target code phase value obtained after it is determined that the current satellite is stably tracked, to obtain a current TIC signal transmission time accurate value of the current satellite; The pseudo-range value corresponding to the current satellite is obtained by subtracting the current TIC signal transmission time accurate value corresponding to the current satellite from a local time.

[0007] Further, in a case where the lock loss duration is not less than the maximum allowed lock loss time corresponding to the current satellite, time information is extracted from the latest pre-lock time ephemeris corresponding to the current satellite after frame synchronization of the current satellite to acquire the pseudo-range value corresponding to the current satellite.

[0008] Further, the method further includes: If the elevation angle value of the current satellite at the latest moment before the loss of lock is not greater than the elevation angle threshold, a new target satellite is selected as the current satellite.

[0009] Furthermore, the method also includes: When the status information of the satellite navigation receiver indicates that the satellite navigation receiver is in normal positioning, the TIC signal transmission time, Doppler value, ephemeris of multiple target satellites and the position information of the satellite navigation receiver are recorded; the target satellites are satellites participating in positioning, and are selected based on the attribute information of all visible satellites.

[0010] Furthermore, the method also includes: The unlock duration is accumulated using local timing pulses, the local time is obtained by recursion using the local timing pulses, and the signal transmission time value of each subsequent TIC is recursively calculated based on the local time. The formula for calculating the local time using the local timing pulse recursion is as follows: ; Among them, t rec0 T is the receiver's local time at the latest moment before the lock was lost. period denoted as TIC signal transmission period, and n is the TIC signal transmission period count value.

[0011] Further, the step of calculating the maximum permissible time of loss of lock for multiple target satellites based on the latest Doppler value before the loss of lock includes: Based on the latest Doppler value f before the loss of lock doprecord Calculate radial velocity V rad0 : ; Among them, f signal Where C is the satellite signal transmission frequency, and C is the speed of light. According to the maximum acceleration A of the satellite navigation receiver max and maximum jerk J max Calculate t rec Maximum possible radial velocity V at any moment rad : ; Calculate the maximum allowable time of loss of lock T for the target satellite to participate in rapid reacquisition and positioning. valid : ; Among them, T prn Where C is the pseudocode period and C is the speed of light.

[0012] Further, the method specifically comprises: In the case that the lock loss duration is less than the maximum allowed lock loss time corresponding to the current satellite, calculating a current TIC signal transmission time coarse value t transmit_raw : ; wherein T period is a TIC signal transmission period, and n is a TIC signal transmission period count value; According to the current TIC signal transmission time coarse value t transmit_raw , calculating a code phase estimation value Φ transmit_raw : ; wherein T prn is a pseudo code period, and floor represents a down rounding operation; In the case that the current satellite is determined to be stably tracked, extracting the target code phase value from a code tracking loop, the target code phase value being defined as a code phase accurate value Φ transmit : calculating a current TIC signal transmission time accurate value t transmit : If |Φ transmit_raw - Φ transmit |≤ 0.5T prn , then: ; If |Φ transmit_raw - Φ transmit |> 0.5T prn , and Φ transmit < 0.5T prn , then: ; If |Φ transmit_raw - Φ transmit |> 0.5T prn , and Φ transmit ≥ 0.5T prn , then: ; wherein T prn is a pseudo code period; calculating the pseudo range value ρ corresponding to the current satellite: According to the local time corresponding to the satellite navigation receiver and the current TIC signal transmission time accurate value corresponding to the current satellite, calculating a pseudo range estimation value ρ temp : ; For the pseudorange estimate ρ corresponding to the current satellite temp The pseudorange value ρ corresponding to the current satellite is obtained by making corrections: ; Where C is the speed of light.

[0013] Furthermore, the method also includes: After sorting the latest elevation angle values ​​of the target satellites before the loss of lock according to the rule of descending, the target satellites are sequentially used as the current satellites to obtain the pseudorange values ​​based on the sorting results.

[0014] The present invention also provides a rapid reacquisition and positioning device for a satellite navigation receiver after loss of lock, which is implemented using any of the above-described rapid reacquisition and positioning methods for a satellite navigation receiver after loss of lock, the device comprising: The status acquisition module is used to acquire the status information of the satellite navigation receiver; The information acquisition module is used to acquire, when the status information of the satellite navigation receiver indicates that the satellite navigation receiver has lost lock, the latest ephemeris of multiple target satellites before the loss of lock, the latest Doppler value before the loss of lock, and the receiver position information of the satellite navigation receiver before the loss of lock; and to define the time corresponding to the latest record before the loss of lock as the latest time before the loss of lock. The information calculation module is used to calculate the elevation angle values ​​of the target satellites at the latest time before the loss of lock based on the latest ephemeris and receiver position information at the latest time before the loss of lock; and to calculate the maximum allowable loss time of the target satellites based on the Doppler value at the latest time before the loss of lock. A satellite selection module is used to select one of the target satellites as the current satellite. The elevation angle determination module is used to determine whether the elevation angle value of the current satellite at the latest moment before the loss of lock is greater than the elevation angle threshold; The loss-of-lock time determination module is used to determine whether the loss-of-lock duration is less than the maximum allowable loss-of-lock time for the current satellite when the latest elevation angle value before the loss of lock is greater than the elevation angle threshold. The pseudorange value calculation module is used to calculate the pseudorange value of the current satellite after determining that the current satellite is being stably tracked, when the duration of the loss of lock is less than the maximum allowable loss of lock corresponding to the current satellite. The positioning calculation module is used to traverse the target satellites until the number of target satellites whose pseudorange values ​​have been obtained meets a preset requirement, and then perform positioning calculation.

[0015] Compared with the prior art, the present invention has the following beneficial effects: After a satellite navigation receiver loses lock, it calculates the elevation angle of the satellites that participated in positioning before the lock was lost at the current moment, and prioritizes the acquisition of satellites with elevation angles greater than a threshold, resulting in higher reacquisition efficiency.

[0016] Based on the Doppler readings and maximum acceleration and jerk of the carrier before the satellite loses lock, the time required for half a code cycle of radial distance change with the receiver is calculated. This time is used as the time threshold for whether the satellite can perform rapid pseudorange estimation, which effectively extends the time when the fast reacquisition and positioning method can be used and greatly improves the reacquisition and positioning capability of the receiver when it loses lock for a long time.

[0017] By utilizing the transmission time at the moment of loss of lock, the loss duration obtained by accumulating local timing pulses, and the code phase value output by the code ring after stable tracking, the pseudorange value can be obtained without bit synchronization and frame synchronization, and can be quickly used for positioning calculation, which greatly speeds up the reacquisition and positioning speed after the receiver loses lock. Attached Figure Description

[0018] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart illustrating a method for rapid reacquisition and positioning of a satellite navigation receiver after loss of lock, provided in an embodiment of the present invention. Figure 2 A flowchart illustrating a satellite and receiver information recording and processing method provided in an embodiment of the present invention; Figure 3 This is a flowchart illustrating a method for selecting available satellites and extracting code phase values ​​based on satellite elevation angle, provided by an embodiment of the present invention. Figure 4 A flowchart illustrating a method for calculating the maximum permissible time of loss of lock-on for a satellite, provided in an embodiment of the present invention; Figure 5 This is a flowchart illustrating a method for rapid calculation of satellite pseudorange provided in an embodiment of the present invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0020] First Embodiment This embodiment provides a method for rapid reacquisition and positioning after a satellite navigation receiver loses lock, the method comprising: Obtain the status information of the satellite navigation receiver; When the status information of the satellite navigation receiver indicates that the satellite navigation receiver has lost lock, the duration of the lock loss, the latest ephemeris of multiple target satellites before the lock loss, the Doppler value of the latest time before the lock loss, and the receiver position information of the satellite navigation receiver at the latest time before the lock loss are obtained; the time corresponding to the latest record before the lock loss is defined as the latest time before the lock loss. Based on the latest ephemeris and receiver position information before the loss of lock, calculate the elevation angle values ​​of multiple target satellites before the loss of lock; and based on the Doppler values ​​before the loss of lock, calculate the maximum allowable time of lock loss for multiple target satellites. Select any target satellite as the current satellite; Determine whether the latest elevation angle value of the satellite before the loss of lock is greater than the elevation angle threshold. If the elevation angle value of the satellite at the latest moment before the loss of lock is greater than the elevation angle threshold, determine whether the duration of the loss of lock is less than the maximum allowable loss of lock for the current satellite. If the duration of the loss of lock is less than the maximum allowable loss of lock for the current satellite, calculate the pseudorange value of the current satellite after confirming that the current satellite is being stably tracked. The target satellites are traversed until the number of target satellites with pseudorange values ​​meets the preset requirements, and then the positioning calculation is performed.

[0021] In an optional embodiment, the calculation of the pseudorange value of the current satellite after determining that the current satellite is being stably tracked specifically includes: Based on the latest signal transmission time value and the duration of the current loss of lock for the current satellite, a rough value of the current TIC signal transmission time of the current satellite is calculated; the latest signal transmission time value before the loss of lock is obtained when the satellite navigation receiver is determined to have lost lock; The approximate value of the current TIC signal transmission time of the current satellite is corrected by the target code phase value obtained after the current satellite is stably tracked, so as to obtain the precise value of the current TIC signal transmission time of the current satellite. The pseudorange value of the current satellite is obtained by subtracting the precise value of the current TIC signal transmission time corresponding to the current satellite from the local time.

[0022] In an optional embodiment, if the duration of the loss of lock is not less than the maximum allowable loss of lock for the current satellite, after the current satellite frame is synchronized, time information is extracted from the latest ephemeris before the loss of lock for the current satellite to obtain the pseudorange value for the current satellite.

[0023] In an optional embodiment, the method further includes: If the elevation angle value of the current satellite at the latest moment before the loss of lock is not greater than the elevation angle threshold, a new target satellite is selected as the current satellite.

[0024] In an optional embodiment, the method further includes: When the satellite navigation receiver's status information indicates that the satellite navigation receiver is in normal positioning, the TIC signal transmission time, Doppler value, ephemeris, and position information of the satellite navigation receiver of multiple target satellites are recorded; the target satellites are those participating in the positioning and are selected based on the attribute information of all visible satellites.

[0025] In an optional embodiment, the method further includes: Obtain the power on / off status of the satellite navigation receiver; When the power-on / off status indicator of the satellite navigation receiver indicates that the satellite navigation receiver is powered on, determine whether the satellite navigation receiver has entered the positioning state; When the satellite navigation receiver enters the positioning state, obtain the status information of the satellite navigation receiver.

[0026] In an optional embodiment, the satellite navigation receiver enters the positioning state after processes such as acquisition, tracking, bit synchronization and frame synchronization, and ephemeris extraction.

[0027] In an optional embodiment, signal loss is monitored simultaneously during satellite signal tracking.

[0028] In an optional embodiment, the method further includes: The duration of the lockout is accumulated using local timing pulses, and the local time is obtained by recursion using local timing pulses. The signal transmission time value of each subsequent TIC is then recursively calculated based on the local time. The formula for calculating local time using local timing pulse recursion is as follows: ; Among them, t rec0 T is the receiver's local time at the latest moment before the lock was lost. period is the TIC signal transmission cycle (controlled by local timing pulses generated by DSP timers or FPGA counters), and n is the TIC signal transmission cycle count value.

[0029] In an optional embodiment, the method further includes: Calculate t rec Target satellite position X at time sat Y sat Z sat The target satellite position calculation process refers to the space signal interface control files of each satellite navigation system; Based on the target satellite position Xsat Y sat Z sat And the latest receiver position information X before the loss of lock. record Y record Z record Calculate t rec Target satellite elevation angle El at any given time; Acquisition is performed on target satellites with an elevation angle El greater than the elevation angle threshold. After successful acquisition, tracking is initiated. Once tracking is stable, the code phase value Φ for one code period is extracted from the code tracking loop. transmit。 In an optional embodiment, the calculation of the maximum permissible time of loss of lock for multiple target satellites based on the latest Doppler value before the loss of lock includes: Based on the latest Doppler value f before the loss of lock doprecord Calculate radial velocity V rad0 : ; Among them, f signal Where C is the satellite signal transmission frequency, and C is the speed of light. Based on the maximum acceleration A of the satellite navigation receiver max and maximum jerk J max Calculate t rec Maximum possible radial velocity V at any moment rad : ; Calculate the maximum allowable time T of loss of lock for the target satellite to participate in rapid reacquisition and positioning. valid : ; Among them, T prn Where C is the pseudocode period and C is the speed of light.

[0030] In an optional embodiment, the method specifically includes: If the duration of the lock-out is less than the maximum permissible lock-out time for the current satellite, calculate a rough value t for the current TIC signal transmission time of the current satellite. transmit_raw : ; Among them, T period Where n is the TIC signal transmission period, and n is the TIC signal transmission period count value; Based on the current TIC signal transmission time, the approximate value t transmit_raw Calculate the code phase estimate Φ within one code period transmit_raw : ; Among them, T prnThe pseudocode period is represented by floor, which indicates the floor operation. Assuming the satellite is currently being stably tracked, the target code phase value is extracted from the code tracking loop. The target code phase value is defined as the accurate code phase value Φ within one code period. transmit : Calculate the precise value t of the current TIC signal transmission time corresponding to the current satellite. transmit : If |Φ transmit_raw -Φ transmit ≤0.5T prn ,but: ; If |Φ transmit_raw -Φ transmit |>0.5T prn , and Φ transmit <0.5T prn ,but: ; If |Φ transmit_raw -Φ transmit 0.5T prn , and Φ transmit ≥0.5T prn ,but: ; Among them, T prn It is a pseudocode period; Calculate the pseudorange value ρ corresponding to the current satellite: Calculate the pseudorange estimate ρ for the current satellite based on the local time corresponding to the satellite navigation receiver and the precise value of the current TIC signal transmission time of the current satellite. temp : ; The pseudorange estimate ρ corresponding to the current satellite temp The pseudorange value ρ corresponding to the current satellite is obtained by making corrections: ; Where C is the speed of light.

[0031] Second Embodiment Unlike the first embodiment, in the satellite navigation receiver fast reacquisition and positioning method provided in this embodiment, the latest elevation angle values ​​of multiple target satellites before the loss of lock are sorted in descending order, and the target satellites are used as the current satellites according to the sorting results to obtain pseudorange values.

[0032] Third Embodiment Please see Figures 1-5The fast reacquisition and positioning method for satellite navigation receivers after loss of lock provided in this embodiment is a fast reacquisition and positioning method for a practical application scenario, and specifically includes the following steps: S1: During the normal positioning process of the satellite navigation receiver, it records information such as the launch time, Doppler, ephemeris, and position of the satellites involved in the positioning; S2: After the satellite navigation receiver loses lock, the duration of the lockout is accumulated using local timing pulses; the elevation angle of each satellite at the current moment is calculated using the satellite ephemeris and receiver position recorded before the lockout, and satellites with elevation angles greater than the threshold are acquired first; after successful acquisition, the tracking state is entered, and the code phase value within one code period is extracted after stable tracking. S3: After the satellite navigation receiver loses lock, the maximum allowable lock-out time for each satellite is calculated using the Doppler values ​​recorded before the lock-out. S4: After the satellite navigation receiver loses lock, for satellites whose lock-out time is less than the maximum allowable lock-out time, a rough value of the current TIC signal transmission time is first calculated using the signal transmission time value recorded before the lock-out and the lock-out time. Then, the rough value of the transmission time is corrected based on the code phase value obtained after stable tracking to obtain the accurate transmission time. The pseudorange value is quickly obtained by subtracting the transmission time from the local time. For satellites whose lock-out time is not less than the maximum allowable lock-out time, the pseudorange value is obtained by extracting time information from the ephemeris after the satellite frame is synchronized. All recorded satellites are traversed, and the positioning calculation is performed when the number of satellites participating in the positioning meets the requirements.

[0033] Reference Figure 2 Step S1 specifically includes: S11: After the satellite navigation receiver is powered on, it enters the positioning state after going through processes such as acquisition, tracking, bit synchronization, frame synchronization, and ephemeris extraction. S12: Monitor whether the signal is lost during satellite signal tracking; S13: Record information such as the launch time, Doppler, ephemeris, and receiver location of the satellites involved in the positioning.

[0034] Reference Figure 3 Step S2 specifically includes: S21: After the receiver loses lock, the subsequent TIC times are recursively calculated based on the recorded local receiver time. The recursion interval is usually selected as the TIC signal period and is controlled by the local timing pulse generated by the DSP timer or FPGA counter.

[0035] The receiver's local time t is obtained by recursion using local timing pulses. rec : ; Among them, t rec0 T is the receiver's local time recorded at the moment of loss of lock.period Where n is the period of the TIC signal, and n is the TIC count value; S22: Calculate t based on the recorded valid ephemeris of each satellite. rec Satellite position X at time sat Y sat Z sat The satellite position calculation process refers to the space signal interface control documents of each satellite navigation system; S23: Based on satellite position X sat Y sat Z sat And the receiver position X recorded before the lock was lost. record Y record Z record Calculate t rec Satellite elevation angle El at any moment; S24: Send satellites with elevation angles El greater than the threshold into the acquisition module. After successful acquisition, switch to tracking. After stable tracking, extract the code phase value Φ within one code period from the code tracking loop. transmit .

[0036] Reference Figure 4 Step S3 specifically includes: S31: Satellite Doppler value f recorded at the moment of loss of lock. doprecord Calculate radial velocity V rad0 : ; Among them, f signal Where C is the satellite signal transmission frequency, and C is the speed of light. S32: Based on the receiver's maximum acceleration A max and maximum jerk J max Calculate t rec Maximum possible radial velocity V at any moment rad : ; S33: Calculate the maximum permissible time T of loss of lock for which the satellite can participate in rapid reacquisition and positioning. valid : ; Among them, T prn Where C is the pseudocode period and C is the speed of light.

[0037] Reference Figure 5 Step S4 specifically includes: S41: If the satellite loss-of-lock time is less than the maximum permissible loss-of-lock time T valid Then calculate its estimated launch time t. transmit_raw : ; Among them, T period Where n is the period of the TIC signal, and n is the TIC count value; S42: Calculate the code phase estimate Φ within one code period based on the transmission time estimate. transmit_raw : ; Among them, T prn The pseudocode period is represented by floor, which indicates the floor operation. S43: With the satellite signal already in a stable tracking state, extract the accurate code phase value Φ for one code period from the code tracking loop. transmit : S44: Calculate the accurate current satellite signal transmission time t transmit : If |Φ transmit_raw -Φ transmit ≤0.5T prn ,but: ; If |Φ transmit_raw -Φ transmit |>0.5T prn , and Φ transmit <0.5T prn ,but: ; If |Φ transmit_raw -Φ transmit 0.5T prn , and Φ transmit ≥0.5T prn ,but: ; Among them, T prn It is a pseudocode period; S45: Calculate the satellite pseudorange ρ: First, calculate the pseudorange estimate ρ based on the receiver's local time and the transmission time. temp : ; For pseudorange estimate ρ temp The accurate satellite pseudorange ρ is obtained by making corrections: ; Where C is the speed of light; S46: If the satellite loss-of-lock time is not less than the maximum permissible loss-of-lock time T valid Then wait for the satellite to complete frame synchronization before extracting time information from the message to obtain the pseudorange value; S47: Traverse all recorded satellites, and perform positioning calculations when the number of satellites participating in the positioning meets the requirements.

[0038] Fourth embodiment This embodiment provides a rapid reacquisition and positioning device for a satellite navigation receiver after lock-up, implemented using the rapid reacquisition and positioning method for a satellite navigation receiver after lock-up as described in the first, second, and third embodiments. The device includes: The status acquisition module is used to acquire the status information of the satellite navigation receiver; The information acquisition module is used to acquire the duration of the loss of lock, the latest ephemeris of multiple target satellites before the loss of lock, the latest Doppler value before the loss of lock, and the receiver position information before the loss of lock when the status information of the satellite navigation receiver indicates that the satellite navigation receiver has lost lock; and to define the time corresponding to the latest record before the loss of lock as the latest time before the loss of lock. The information calculation module is used to calculate the elevation angle values ​​of multiple target satellites at the latest time before the loss of lock based on the latest ephemeris and receiver position information at the latest time before the loss of lock; and to calculate the maximum allowable time of loss of lock for multiple target satellites based on the Doppler value at the latest time before the loss of lock. The satellite selection module is used to select any target satellite as the current satellite. The elevation angle determination module is used to determine whether the latest elevation angle value of the satellite before the loss of lock is greater than the elevation angle threshold. The loss-of-lock time determination module is used to determine whether the loss-of-lock duration is less than the maximum allowable loss-of-lock time for the current satellite if the elevation angle value at the latest moment before the current satellite loses lock is greater than the elevation angle threshold. The pseudorange calculation module is used to calculate the pseudorange value of the current satellite after determining that the current satellite is being stably tracked, when the duration of the loss of lock is less than the maximum allowable loss of lock for the current satellite. The positioning and calculation module is used to traverse the target satellites until the number of target satellites with pseudorange values ​​meets the preset requirements, and then perform positioning and calculation.

[0039] Fifth Embodiment Unlike the fourth embodiment, the satellite selection module in the satellite navigation receiver rapid reacquisition positioning device after loss of lock provided in this embodiment is used to sort the latest elevation angle values ​​of multiple target satellites before the loss of lock according to the rule of descending order, and then select them sequentially according to the sorting result.

[0040] Sixth Embodiment This embodiment provides a rapid reacquisition and positioning device for a satellite navigation receiver after loss of lock, which is implemented using the rapid reacquisition and positioning method for a satellite navigation receiver after loss of lock as described in the first embodiment, the second embodiment, and the third embodiment. The device includes an information acquisition module, a rapid acquisition module, a maximum allowable loss of lock time calculation module, a pseudorange calculation module, and a positioning solution module. The information acquisition module records information such as the launch time, Doppler, ephemeris, and receiver position of the satellites involved in positioning during normal operation of the satellite navigation receiver; The fast acquisition module calculates the satellite position based on the saved satellite ephemeris and the receiver's local time, and calculates the satellite elevation angle using the satellite position and the receiver position. It prioritizes the acquisition and tracking of satellites with elevation angles greater than the elevation angle threshold. The maximum permissible time out of lock calculation module calculates the maximum permissible time out of lock for each satellite based on the Doppler data recorded at the moment of satellite loss of lock. The pseudorange calculation module calculates the pseudorange estimate based on the pseudorange value recorded at the moment of satellite loss of lock and the cumulative value of loss of lock time if the loss of lock time is less than the maximum allowable loss of lock time of satellite. After the satellite enters a stable tracking state, the pseudorange estimate is corrected by the code phase value within a code period extracted from the code tracking loop to obtain the accurate pseudorange value; otherwise, the pseudorange value is calculated after frame synchronization is completed. The positioning calculation module iterates through all recorded satellites and performs positioning calculations when the number of satellites participating in the positioning meets the requirements.

[0041] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features of the present invention can be arbitrarily combined with each other.

Claims

1. A method for rapid reacquisition and positioning after a satellite navigation receiver loses lock, characterized in that, The method includes: Obtain the status information of the satellite navigation receiver; When the status information of the satellite navigation receiver indicates that the satellite navigation receiver has lost lock, the duration of the loss of lock, the latest ephemeris of multiple target satellites before the loss of lock, the latest Doppler value before the loss of lock, and the receiver position information of the satellite navigation receiver before the loss of lock are obtained; the time corresponding to the latest record before the loss of lock is defined as the latest time before the loss of lock. Based on the latest ephemeris and receiver position information before the loss of lock, calculate the latest elevation angle values ​​of the target satellites before the loss of lock; and based on the Doppler values ​​before the loss of lock, calculate the maximum allowable time of lock-up for the target satellites. Select one of the target satellites as the current satellite; Determine whether the latest elevation angle value of the current satellite before the loss of lock is greater than the elevation angle threshold; If the elevation angle value of the current satellite at the latest moment before the loss of lock is greater than the elevation angle threshold, it is determined whether the duration of the loss of lock is less than the maximum allowable loss of lock time for the current satellite. If the duration of the loss of lock is less than the maximum allowable loss of lock for the current satellite, the pseudorange value of the current satellite is calculated after it is determined that the current satellite is being stably tracked. The target satellites are traversed until the number of target satellites whose pseudorange values ​​have been obtained meets a preset requirement, and then the positioning calculation is performed.

2. The method for rapid reacquisition and positioning after loss of lock in a satellite navigation receiver according to claim 1, characterized in that, The step of calculating the pseudorange value of the current satellite after determining that the current satellite is being stably tracked specifically includes: Based on the latest signal transmission time value before the current satellite lost lock and the duration of the loss of lock, a rough value of the current TIC signal transmission time of the current satellite is calculated; the latest signal transmission time value before the loss of lock is obtained when the satellite navigation receiver is determined to have lost lock; The coarse value of the current TIC signal transmission time corresponding to the current satellite is corrected by the target code phase value obtained after the current satellite is determined to be stably tracked, so as to obtain the precise value of the current TIC signal transmission time of the current satellite. The pseudorange value corresponding to the current satellite is obtained by subtracting the precise value of the current TIC signal transmission time corresponding to the current satellite from the local time.

3. The method for rapid reacquisition and positioning after loss of lock in a satellite navigation receiver according to claim 1, characterized in that, If the duration of the loss of lock is not less than the maximum allowable loss of lock for the current satellite, after the current satellite frame is synchronized, time information is extracted from the latest ephemeris before the loss of lock for the current satellite to obtain the pseudorange value for the current satellite.

4. The method for rapid reacquisition and positioning after loss of lock in a satellite navigation receiver according to claim 1, characterized in that, The method further includes: If the elevation angle value of the current satellite at the latest moment before the loss of lock is not greater than the elevation angle threshold, a new target satellite is selected as the current satellite.

5. The method for rapid reacquisition and positioning after loss of lock in a satellite navigation receiver according to claim 1, characterized in that, The method further includes: When the status information of the satellite navigation receiver indicates that the satellite navigation receiver is in normal positioning, the TIC signal transmission time, Doppler value, ephemeris of multiple target satellites and the position information of the satellite navigation receiver are recorded; the target satellites are satellites participating in positioning, and are selected based on the attribute information of all visible satellites.

6. The method for rapid reacquisition and positioning after loss of lock in a satellite navigation receiver according to claim 2, characterized in that, The method further includes: The unlock duration is accumulated using local timing pulses, the local time is obtained by recursion using the local timing pulses, and the signal transmission time value of each subsequent TIC is recursively calculated based on the local time. The formula for calculating the local time using the local timing pulse recursion is as follows: ； Among them, t rec0 T is the receiver's local time at the latest moment before the lock was lost. period denoted as TIC signal transmission period, and n is the TIC signal transmission period count value.

7. The method for rapid reacquisition and positioning of a satellite navigation receiver after loss of lock, as described in claim 6, is characterized in that... The calculation of the maximum permissible time of loss of lock for multiple target satellites based on the latest Doppler value before the loss of lock includes: Based on the latest Doppler value f before the loss of lock doprecord Calculate radial velocity V rad0 : ； Among them, f signal Where C is the satellite signal transmission frequency, and C is the speed of light. According to the maximum acceleration A of the satellite navigation receiver max and maximum jerk J max Calculate t rec Maximum possible radial velocity V at any given time rad : ； Calculate the maximum allowable time of loss of lock T for the target satellite to participate in rapid reacquisition and positioning. valid : ； Among them, T prn Where C is the pseudocode period and C is the speed of light.

8. The method for rapid reacquisition and positioning after loss of lock in a satellite navigation receiver according to claim 7, characterized in that, The method specifically includes: If the duration of the lock-out is less than the maximum permissible lock-out time for the current satellite, calculate a rough value t for the current TIC signal transmission time of the current satellite. transmit_raw： ; Among them, T period Where n is the TIC signal transmission period, and n is the TIC signal transmission period count value; Based on the approximate value t of the current TIC signal transmission time transmit_raw计算一个码周期内的码相位估计值Φtransmit_raw : ; Among them, T prn The pseudocode period is represented by floor, which indicates the floor operation. If the current satellite is determined to be stably tracked, the target code phase value is extracted from the code tracking loop. The target code phase value is defined as the code phase accuracy value Φ within one code period. transmit : Calculate the precise value t of the current TIC signal transmission time corresponding to the current satellite. transmit : If |Φ transmit_raw -Φtransmit ≤0.5T prn ,but: ； If |Φ transmit_raw -Φtransmit |>0.5T prn , and Φ transmit <0.5T prn ,but: ； If |Φ transmit_raw -Φtransmit 0.5T prn , and Φ transmit ≥0.5T prn ,but: ; Among them, T prn It is a pseudocode period; Calculate the pseudorange value ρ corresponding to the current satellite: Calculate the pseudorange estimate ρ corresponding to the current satellite based on the local time corresponding to the satellite navigation receiver and the precise value of the current TIC signal transmission time corresponding to the current satellite. temp : ； For the pseudorange estimate ρ corresponding to the current satellite temp The pseudorange value ρ corresponding to the current satellite is obtained by making corrections: ； Where C is the speed of light.

9. The method for rapid reacquisition and positioning of a satellite navigation receiver after loss of lock, as described in any one of claims 1 to 8, is characterized in that, The method further includes: After sorting the latest elevation angle values ​​of the target satellites before the loss of lock according to the rule of descending, the target satellites are sequentially used as the current satellites to obtain the pseudorange values ​​based on the sorting results.

10. A rapid reacquisition and positioning device for a satellite navigation receiver after loss of lock, implemented using the rapid reacquisition and positioning method for a satellite navigation receiver after loss of lock as described in any one of claims 1 to 9, characterized in that, The device includes: The status acquisition module is used to acquire the status information of the satellite navigation receiver; The information acquisition module is used to acquire, when the status information of the satellite navigation receiver indicates that the satellite navigation receiver has lost lock, the latest ephemeris of multiple target satellites before the loss of lock, the latest Doppler value before the loss of lock, and the receiver position information of the satellite navigation receiver before the loss of lock; and to define the time corresponding to the latest record before the loss of lock as the latest time before the loss of lock. The information calculation module is used to calculate the elevation angle values ​​of the target satellites at the latest time before the loss of lock based on the latest ephemeris and receiver position information at the latest time before the loss of lock; and to calculate the maximum allowable loss time of the target satellites based on the Doppler value at the latest time before the loss of lock. A satellite selection module is used to select one of the target satellites as the current satellite. The elevation angle determination module is used to determine whether the elevation angle value of the current satellite at the latest moment before the loss of lock is greater than the elevation angle threshold; The loss-of-lock time determination module is used to determine whether the loss-of-lock duration is less than the maximum allowable loss-of-lock time for the current satellite when the latest elevation angle value before the loss of lock is greater than the elevation angle threshold. The pseudorange value calculation module is used to calculate the pseudorange value of the current satellite after determining that the current satellite is being stably tracked, when the duration of the loss of lock is less than the maximum allowable loss of lock corresponding to the current satellite. The positioning calculation module is used to traverse the target satellites until the number of target satellites whose pseudorange values ​​have been obtained meets a preset requirement, and then perform positioning calculation.

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