A positioning method based on sparse measurement signals

Abstract

The application discloses a positioning method based on sparse measurement signals and belongs to the technical field of positioning.The application comprises the following steps: performing corresponding positioning methods according to received pseudo-range measurement values or Doppler measurement values or simultaneously received pseudo-range measurement values and Doppler measurement values, and solving positioning problems under the conditions that measurement signals are time-division arrival, a beacon transmitting measurement signals is sparse (less than four), measurement values are sparse (less than four) and the like.The application can determine the user position and clock difference when pseudo-range and Doppler measurement values are time-division arrival and the pseudo-range and Doppler measurement values are sparse through the calculation of the user position and clock difference.

Description

Technical Field

[0001] This invention relates to a positioning method based on sparse measurement signals, belonging to the field of positioning technology. Background Technology

[0002] Global satellite navigation systems, represented by BeiDou, operate continuously and stably, providing navigation, positioning, and timing services to users worldwide. However, in complex electromagnetic environments, with severe obstruction, sparse available measurement signals, or when using non-traditional navigation signals for positioning, users cannot simultaneously receive measurement signals transmitted from four or more different beacons, thus hindering navigation and positioning.

[0003] Traditional navigation and positioning methods and equipment can no longer function properly under the above conditions, especially when the measurement signals arrive in time-division format, the beacons transmitting the measurement signals are sparse (less than four), and the measurement values ​​are sparse (less than four). However, many special users need to obtain accurate navigation and positioning information under such measurement conditions. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a positioning method based on sparse measurement signals, which solves the positioning problem when the measurement signals arrive in time division, the beacons transmitting the measurement signals are sparse (less than four), and the measurement values ​​are sparse (less than four).

[0005] The technical solution of the present invention is: a positioning method based on sparse measurement signals, comprising: performing a corresponding positioning method according to the received pseudorange measurement value or Doppler measurement value, or simultaneously receiving pseudorange measurement value and Doppler measurement value; The positioning method based on sparse pseudorange measurements is as follows: pseudorange positioning equations are formed by using pseudorange measurements from the same or multiple beacons that arrive at different times, and the user's position and clock error are reduced to the same time and substituted into the pseudorange positioning equations. The user's position and clock error are then solved to obtain the positioning equations. The positioning method based on sparse Doppler measurements is as follows: Doppler measurements are obtained by receiving signals transmitted by the same beacon or multiple beacons, Doppler positioning equations are constructed using the Doppler measurements, and the user's position and clock error are reduced to the same time and substituted into the Doppler positioning equations. The positioning equations are then solved to obtain the user's position and clock error. The positioning method based on sparse pseudorange and Doppler measurements is as follows: signals transmitted from the same beacon or multiple beacons are received simultaneously to obtain pseudorange and Doppler measurements. These measurements are used to form a pseudorange-Doppler positioning equation. The user's position and clock error are reduced to the same time and substituted into the pseudorange-Doppler positioning equation. The positioning equation is then solved to obtain the user's position and clock error.

[0006] Furthermore, the positioning method based on sparse pseudorange measurements includes the following steps: Step 201: The user terminal receives the beacon measurement signal and generates pseudorange measurement value. The inertial navigation system outputs the position change at the corresponding time. If more than or equal to the pseudorange measurement value of four beacons is obtained at the same time, proceed to step 202. If no more than or equal to the measurement value of four beacons is obtained, proceed to step 203. Step 202: The user calculates or obtains the position and clock difference when the beacon transmits the measurement signal, eliminates various error sources contained in the measurement value, and calculates the user's position at the current time; Step 203: The user continues to receive measurement values ​​until four or more measurement values ​​are received. The user's desired positioning accuracy is... Evaluate the PDOP value of the localization equation at this point. If the received value is less than the given value, then the system will continue to receive measurement values. If the value is less than the given value, the system will use the received N pseudorange measurement values ​​for positioning. This represents the standard deviation of the beacon's position and time error. N is the standard deviation of the measurement error of the pseudorange measurement; N is a positive integer; Step 204, if the waiting period for the measurement value exceeds... If the PDOP value of the positioning equation still cannot meet the condition of step 203 after a certain number of seconds, the calculation will restart from the second measurement time. If the time period exceeds a certain threshold... If the time interval is still insufficient, the calculation will restart from the third measurement time, and so on.

[0007] Furthermore, the evaluation of the PDOP value of the localization equation includes: Step 301: Obtain N pseudorange measurements. and N-1 position change vectors ; Step 302, using the origin of the coordinate system Using the position change vector as a reference point, the position at time T corresponding to the last time moment is obtained. The calculation method is as follows: in, Represents the accumulation of vectors; Step 303, using the obtained N-1 and reference origin And the location of the beacon at each time point, according to Calculate the corresponding PDOP value; where, The trace of the matrix, ; Indicates the reference origin To the Known points The direction cosine.

[0008] Furthermore, the method for positioning using the received N pseudorange measurements includes: Step 401: Obtain N pseudorange measurements. The position and time of N beacon transmission measurement signals, N local clock times, and N-1 position change vectors. The user's location at each moment is as follows: Furthermore, the user's location is unknown. Step 402, assuming the user needs Location at any moment Using the known position change vector , will other User location at any given time is calculated to The time is calculated as follows: ; Step 403, assuming the terminal clock difference at each measurement reception time is... Furthermore, since the terminal clock bias is unknown, the clock bias variation is corrected to below nanoseconds, effectively making the receiver clock bias over the entire time period equivalent to a constant value. ; Step 404: Add the position correction error and clock error to the measurement error: In the formula, It is the standard deviation of the original measurement error. It is the standard deviation of the measurement error of the inertial navigation system, determined according to the inertial navigation system. It is the standard deviation of the error after the terminal clock bias is reduced. It is the standard deviation of the error of the new measurement value; Step 405, the equation composed of the received N observations can be expressed as: In the formula, express The location of the time beacon, and the location of the user terminal at each time. Transform to step 402 Terminal clock difference at each moment Transform to step 403 The above equation is linearized using a Taylor expansion, and then solved using the iterative least squares method to obtain the position at time t. The method for calculating its position at time T is as follows: .

[0009] Furthermore, the localization method based on sparse Doppler measurements includes the following steps: Step 501: The user terminal receives the beacon measurement signal and generates Doppler measurement values. The inertial navigation system outputs the position change at the corresponding time. If more than four Doppler measurement values ​​are received, proceed to step 502; otherwise, continue receiving measurement values. Step 502: Use the received N Doppler measurements to locate the position. If the positioning results converge, the positioning is complete; otherwise, continue to step 503. Step 503, continue receiving Doppler measurements. If the difference between the measured values ​​at different times is within... Within seconds, all observations are used to continue positioning based on step 502; if more than that... If the time interval exceeds a certain number of seconds, the calculation will restart from the second measurement time. If the positioning convergence is not achieved in step 502, the calculation will restart from the third measurement time, and so on.

[0010] Furthermore, the method for localization using the received N Doppler measurements includes: Step 601: Obtain N Doppler measurements. The positions and times of N beacon transmission measurement signals, N local receiver times, and N-1 position change vectors. The user's location at each moment is as follows: Furthermore, the user's location is unknown. Step 602: Reuse step 402 to calculate the position, and convert the clock drift during this period into a constant value. ; Step 603, the relationship between the frequency of the N Doppler measurements received by the user at each moment and the satellite transmission frequency is as follows: In the above formula, It is the satellite's speed relative to the user at any given moment. To measure the original frequency of the signal, Zhong Piao, It's the speed of light. It is the user location that needs to be calculated. express The position of the beacon at time; its linear representation using Taylor expansion, and the solution to this equation to obtain the user's position at the corresponding time; the calculation using the method in step 405. The location at any given moment.

[0011] If the above process fails to achieve positioning, return to step 503 to continue execution.

[0012] Furthermore, the steps of the localization method based on sparse pseudorange and Doppler measurements include: Step 701: The user terminal receives the beacon measurement signal and generates pseudorange and Doppler measurement values. The inertial navigation system outputs the position change at the corresponding time. If more than four pseudorange measurement values ​​and corresponding Doppler measurement values ​​are received, step 702 is executed; otherwise, the measurement values ​​are received. Step 702: Use the received N pseudorange and Doppler measurements to perform positioning. If the positioning results converge, the positioning is complete; otherwise, continue to step 703. Step 703, continue receiving pseudorange and Doppler measurements. If the difference between the measured values ​​at any given time is within... If within seconds, then all observations are used to continue positioning based on step 702; if it exceeds... If the time interval exceeds a certain number of seconds, the calculation will restart from the second measurement point. If the positioning convergence is not achieved in step 702, the calculation will restart from the third measurement time, and so on.

[0013] Furthermore, the method for positioning using the received N pseudoranges and Doppler measurements includes: Step 801: Obtain N pseudorange measurements. N Doppler measurements The positions and times of N beacon transmission measurement signals, N local receiver times, and N-1 position change vectors. The user's location at each moment is as follows: Furthermore, the user's location is unknown. Step 802: Repeat step 402 to correct the position, and repeat step 403 to correct the clock error. The receiver clock error is equivalent to a constant value throughout the entire time period. Zhong Piao is equivalent to a constant value. The clock's movement during this period is equivalent to a constant value. ; Step 803, the equation composed of the received N pseudorange observations and Doppler observations is expressed as: Represent it linearly and solve the equation to obtain the user's position at the corresponding time; if needed The position of the time is calculated using the method in step 405; If the above process fails to locate the target, return to step 703 to continue execution.

[0014] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the positioning method based on sparse measurement signals.

[0015] A positioning device based on sparse measurement signals, comprising: The measurement signal receiving module is used to receive measurement signals that match the beacon's transmitted signals and generate corresponding observations for receiving and analyzing the beacon's position and clock bias. The beacon is a GNSS navigation satellite or any device or apparatus capable of transmitting measurement signals. The measurement signals are matched with the user terminal where the positioning device is located, and there are no restrictions on its signal transmission frequency and bandwidth. The measurement values ​​are either individual pseudorange measurements, individual Doppler measurements, or pseudorange and Doppler measurements, with carrier phase measurements appearing in pairs with pseudorange measurements. The inertial navigation module is used to output the change of the terminal position at the current observation time relative to the previous observation time; it calculates or acquires the position and time of the beacon transmitting the measurement signal. For all beacons, their position and time are in the same spatiotemporal coordinate system. If there is a deviation, it is restored to the same spatiotemporal coordinate system by a known correction amount. At the same time, the standard deviation of the error of the beacon's position and time can be obtained by statistics or calculation. The time-frequency module, equipped with a clock, provides time-frequency information to both the receiving module and the inertial navigation module; within a certain time period... The clock speed is stable, and in The clock error variation within the time period is in the range of nanoseconds or less, or it is corrected by a certain coefficient or method to control the clock error variation to be in the range of nanoseconds or less; the time frequency of the inertial navigation equipment is consistent with the time frequency of the measurement value generation. The calculation module is used to perform the operation of the positioning method based on sparse measurement signals.

[0016] The advantages of this invention compared to the prior art are as follows: by calculating the user's location and clock error, this invention can determine the user's location and clock error even when the pseudorange and Doppler measurements arrive in time and are sparse. Attached Figure Description

[0017] Figure 1 A schematic flowchart of a positioning method according to Embodiment 1 of the present invention is shown; Figure 2 A schematic flowchart of a positioning method according to Embodiment 2 of the present invention is shown; Figure 3 A schematic flowchart of a positioning method according to Embodiment 3 of the present invention is shown; Figure 4A schematic flowchart of a positioning method according to Embodiment 4 of the present invention is shown; Figure 5 A schematic diagram of a positioning device structure according to Embodiment 5 of the present invention is shown; Figure 6 A schematic diagram of a positioning device structure provided according to Embodiment 5 of the present invention is shown. Detailed Implementation

[0018] To better understand the above technical solutions, the technical solutions of this application will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. In the absence of conflict, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0019] The following description, in conjunction with the accompanying drawings, provides a more detailed explanation of a localization method based on sparse measurement signals provided in this application. Specific implementation methods may include (e.g.) Figures 1-6 As shown): The corresponding positioning method is executed based on the received pseudorange measurement value or Doppler measurement value, or both pseudorange measurement value and Doppler measurement value.

[0020] The positioning method based on sparse pseudorange measurements is as follows: pseudorange positioning equations are formed by using pseudorange measurements from the same or multiple beacons that arrive at different times, and the user's position and clock error are reduced to the same time and substituted into the pseudorange positioning equations. The user's position and clock error are then solved to obtain the positioning equations. The positioning method based on sparse Doppler measurements is as follows: Doppler measurements are obtained by receiving signals transmitted by the same beacon or multiple beacons, Doppler positioning equations are constructed using the Doppler measurements, and the user's position and clock error are reduced to the same time and substituted into the Doppler positioning equations. The positioning equations are then solved to obtain the user's position and clock error. The positioning method based on sparse pseudorange and Doppler measurements is as follows: signals transmitted from the same beacon or multiple beacons are received simultaneously to obtain pseudorange and Doppler measurements. These measurements are used to form a pseudorange-Doppler positioning equation. The user's position and clock error are reduced to the same time and substituted into the pseudorange-Doppler positioning equation. The positioning equation is then solved to obtain the user's position and clock error.

[0021] One aspect of the present invention provides a positioning method based on sparse measurement signals, comprising: When the user terminal receives only pseudorange measurement values, it executes a positioning method based on sparse pseudorange measurement values. When the user terminal receives only Doppler measurement values, it executes a positioning method based on sparse Doppler measurement values. When the received values ​​include both pseudorange and Doppler measurement values, the user terminal executes a positioning method based on both sparse pseudorange and Doppler measurement values.

[0022] Furthermore, this invention provides a positioning method based on sparse pseudorange measurements. It includes: The user terminal receives beacon measurement signals and generates pseudorange measurements. The inertial navigation system outputs the position change at the corresponding time. If more than or equal to four beacon pseudorange measurements are received at the same time, the user calculates or obtains the position and clock error when the beacon transmitted the measurement signal, eliminates various error sources contained in the measurement values, and uses methods such as least squares to calculate the user's current position. If there are no more than or equal to four beacon measurements, the user continues to receive measurement values ​​until four or more are received. The PDOP value of the positioning equation at this time is evaluated and compared with the user's expected accuracy. If it is less than the user's expected accuracy, positioning is performed using the N received pseudorange measurements. If the waiting time for measurement values ​​exceeds [a certain threshold], [further steps are taken]. If the positioning equation still cannot satisfy the condition of step 203 after a certain number of seconds, then the calculation will restart from the second measurement time. If the time period exceeds [a certain threshold], [the calculation will continue]. If the second is still insufficient, the calculation restarts from the third measurement time, and so on. The above method requires calculating the PDOP value and also adjusting for the time-division multiplexing of the user's location and the user's clock difference. The PDOP value is the Spatial Position Precision Factor.

[0023] Furthermore, this invention provides a localization method based on sparse Doppler measurements. It includes: The user terminal receives beacon measurement signals and generates Doppler measurements. The inertial navigation system outputs the position change at the corresponding time. If more than four Doppler measurements are received, the system uses the received N Doppler measurements for positioning. If the positioning results converge, positioning is complete; otherwise, it continues to receive measurement values. If the difference between the measurement values ​​at different times is within a certain range... Within seconds, then continue positioning all observations; if it exceeds... If the time interval exceeds a certain number of seconds, the calculation will restart from the second measurement point. If the positioning convergence is not achieved within seconds, the calculation restarts from the third measurement time, and so on. In the above method, the user's location and clock difference at the time of the time-division measurement need to be normalized to the same time.

[0024] Furthermore, this invention provides a positioning method based on sparse pseudorange and Doppler measurements. It includes: The user terminal receives beacon measurement signals and generates pseudorange and Doppler measurements. The inertial navigation system outputs the position change at the corresponding time. If more than four pseudorange and corresponding Doppler measurements are received, positioning is performed using the received N pseudorange and Doppler measurements. If the positioning results converge, positioning is complete; otherwise, measurement values ​​are received again. If the difference between the measurement values ​​at different times is within a certain range... Within seconds, then continue positioning all observations; if it exceeds... If the time interval exceeds a certain number of seconds, the calculation will restart from the second measurement point. If the positioning convergence is not achieved within seconds, the calculation restarts from the third measurement time, and so on. In the above method, the user's location and clock difference at the time of the time-division measurement need to be normalized to the same time.

[0025] Another aspect of the present invention provides a positioning device, comprising: The system comprises a measurement signal receiving module, an inertial navigation module, a time-frequency module, and a calculation module. Specifically: the measurement signal receiving module receives measurement signals that match the beacon's transmitted signals and generates corresponding observations; the inertial navigation module receives and analyzes the beacon's position and clock difference; the time-frequency module outputs the change in the terminal position relative to the previous observation time; the time-frequency module is equipped with a highly stable clock, providing time-frequency information to both the receiving and inertial navigation modules; the calculation module includes a signal processing unit, a data processing unit, a storage unit, and various communication interfaces, capable of executing the corresponding operations of the described method.

[0026] The solution provided in the embodiments of this application includes: Example 1 Figure 1 A schematic diagram of a positioning method according to Embodiment 1 of the present invention is shown. The user terminal is capable of receiving measurement signals transmitted by a beacon and generating corresponding measurement values; the user terminal is capable of calculating or acquiring the position and time when the beacon transmitted the measurement signals; the user terminal is equipped with a highly stable clock capable of outputting the local time when the measurement values ​​are generated; the user terminal is equipped with an inertial navigation system capable of outputting the change in terminal position between the current measurement value generation time and the previous measurement value generation time, and can output the terminal velocity at the current measurement value generation time.

[0027] like Figure 1 As shown, the method includes: Step 101: When the user terminal receives only pseudorange measurement values, execute the positioning method based on sparse pseudorange measurement values.

[0028] Step 102: When the user terminal receives only Doppler measurement values, execute the positioning method based on sparse Doppler measurement values.

[0029] Step 103: When the received data includes pseudorange and Doppler measurements, the user terminal executes a positioning method based on sparse pseudorange and Doppler measurements.

[0030] Example 2 Figure 2A schematic diagram of a positioning method according to Embodiment 2 of the present invention is shown. The method provided in this embodiment is a processing method when the user terminal receives only pseudorange measurement values, such as... Figure 2 As shown, the method includes: Step 201: The user terminal receives the beacon measurement signal and generates pseudorange measurement value. The inertial navigation system outputs the position change at the corresponding time. If more than or equal to the pseudorange measurement value of four beacons is obtained at the same time, proceed to step 202. If no more than or equal to the measurement value of four beacons is obtained, proceed to step 203. Step 202: The user calculates or obtains the position and clock difference when the beacon transmits the measurement signal, eliminates various error sources contained in the measurement value, and calculates the user's position at the current time using methods such as least squares. Step 203: The user continues to receive measurement values ​​until four or more measurement values ​​are received. The user's desired positioning accuracy is... Evaluate the PDOP value of the localization equation at this point. Then continue to receive measurement values. If the value is less than the received N pseudorange measurement values, use them for positioning. Step 204, if the waiting period for the measurement value exceeds... If the PDOP value in the positioning equation still does not meet the condition of step 203, then the calculation will restart from the second measurement time. If the time period exceeds [a certain threshold], [further steps will be taken]. If the second is still insufficient, then the calculation will restart from the third measurement time, and so on.

[0031] The method for calculating PDOP in step 203 includes: Step 301: At this point, N pseudorange measurements are obtained. At the same time, N-1 position change vectors were obtained. ; Step 302, using the origin of the coordinate system Using the position change vector as a reference point, the position at time T corresponding to the last time moment is obtained. The calculation method is as follows: Where sum represents the accumulation of vectors; Step 303, using the obtained N-1 and reference origin The corresponding PODP value is obtained by substituting the location of the beacon at each time point into the formula shown below.

[0032] In the above formula, The trace of the matrix, It can be expressed by the following formula: in, Indicates the reference origin To the Known points The direction cosine. Obtain the PDOP value.

[0033] Methods for users to perform positioning using sparse pseudorange measurements include: Step 401: At this point, N pseudorange measurements are obtained. The position and time of N beacon transmission measurement signals, N local clock times, and N-1 position change vectors. The user's location at each moment is as follows: Furthermore, the user's location is unknown. Step 402, assume the user needs the location at time t. Using the known position change vector The user locations at other times T can be regressed to time t. The calculation method is as follows: Step 403, assuming the terminal clock difference at each measurement reception time is... Furthermore, since the terminal clock bias is unknown, and the terminal is equipped with a highly stable clock, the clock bias variation can be corrected to below nanoseconds during the time it takes to receive all measurements (usually a polynomial or constant correction method, depending on the characteristics of the highly stable clock). Therefore, the receiver clock bias throughout the entire time period can be considered equivalent to a constant value. ; Step 404: In addition to the original measurement error, since position and clock error reduction were performed in steps 402 and 403, the position reduction error and clock error reduction error are added to the measurement error. In the formula, It is the standard deviation of the original measurement error. It is the standard deviation of the measurement error of the inertial navigation system, determined according to the inertial navigation system. It is the standard deviation of the error after the terminal clock error is reduced (in units of distance). It is the standard deviation of the error of the new measurement value.

[0034] Step 405, the equation composed of the received N observations can be expressed as: In the formula, all known errors have been eliminated. express The location of the time beacon, based on the elimination of beacon clock bias, and the location of the user terminal at each time. The process has been completed via step 402. Terminal clock difference at each moment The process has been completed via step 403. Linearizing the above equation, we get: In the above formula: The linearized equation is solved using a general iterative least squares method to obtain the position at time t. If the user needs to find the position at time T, the calculation method is as follows: Example 3 Figure 3 A schematic diagram of a positioning method according to Embodiment 3 of the present invention is shown. The method provided in this embodiment is a processing method when the user terminal receives only Doppler measurement values.

[0035] like Figure 3 As shown, the method includes: Step 501: The user terminal receives the beacon measurement signal and generates Doppler measurement values. The inertial navigation system outputs the position change at the corresponding time. If more than four Doppler measurement values ​​are received, proceed to step 502; otherwise, continue receiving measurement values. Step 502: Use the received N Doppler measurements to locate the position. If the positioning results converge, the positioning is complete; otherwise, continue to step 503. Step 503, continue receiving Doppler measurements. If the difference between the measured values ​​at different times is within... If within seconds, then all observations are used to continue positioning based on step 502; if it exceeds... If the time interval exceeds a certain number of seconds, the calculation will restart from the second measurement point. If the positioning convergence is not achieved in step 502, then the calculation will restart from the third measurement time, and so on.

[0036] Methods for localization using Doppler measurements include: Step 601: At this point, N Doppler measurements have been obtained. The positions and times of N beacon transmission measurement signals, N local receiver times, and N-1 position change vectors. The user's location at each moment is as follows: Furthermore, the user's location is unknown. Step 602: Reuse step 402 to calculate the position. The clock drift of the terminal clock is stabilized, and the clock drift during this period can be equivalent to a constant value. ; Step 603: Since the position and clock drift were reduced in the previous step, the position and clock drift at each moment can be reduced to... The relationship between the frequency of the N Doppler measurements received by the user at each moment and the satellite transmission frequency is as follows: In the above formula, It is the satellite's speed relative to the user at any given moment. Indicates the original frequency of the measured signal. Zhong Piao, It's the speed of light. It is the user location that needs to be calculated. express The position of the time beacon. Represent it linearly using Taylor expansion: In the formula: After obtaining the linearized equation, the localization result is obtained using the general Kalman filter method. If no localization result is obtained, the process returns to step 503 to continue execution.

[0037] Example 4 Figure 4 A schematic diagram of a positioning method according to Embodiment 4 of the present invention is shown. The method provided in this embodiment is a processing method when a user terminal receives measurement values ​​that simultaneously include pseudorange and Doppler measurement values.

[0038] like Figure 4 As shown, the method includes: Step 701: The user terminal receives the beacon measurement signal and generates pseudorange and Doppler measurement values. The inertial navigation system outputs the position change at the corresponding time. If more than four pseudorange measurement values ​​and corresponding Doppler measurement values ​​are received, step 702 is executed; otherwise, the measurement values ​​are received. Step 702: Use the received N pseudorange and Doppler measurements to perform positioning. If the positioning results converge, the positioning is complete; otherwise, continue to step 703. Step 703, continue receiving pseudorange and Doppler measurements. If the difference between the measured values ​​at any given time is within... If within seconds, then all observations are used to continue positioning based on step 702; if it exceeds... If the time interval exceeds a certain number of seconds, the calculation will restart from the second measurement point. If the positioning convergence is not achieved in step 702, then the calculation will restart from the third measurement time, and so on.

[0039] Further localization steps using pseudorange and Doppler measurements include: Step 801: At this point, N pseudorange measurements are obtained. N Doppler measurements The positions and times of N beacon transmission measurement signals, N local receiver times, and N-1 position change vectors. The user's location at each moment is as follows: Furthermore, the user's location is unknown. Step 802: Repeat step 402 to correct the position, and repeat step 403 to correct the clock error. The receiver clock error over the entire time period can be equivalent to a constant value. The clock drift of the terminal clock is stable, and the clock drift during this period can be equivalent to a constant value. ; Step 803, the equation composed of the received N pseudorange observations and Doppler observations can be expressed as: Since the position and clock drift were reduced in the previous step, the position and clock drift at each moment can be reduced to... At time t, the equation consisting of the N received pseudorange observations and Doppler observations can be expressed as: The terms in the above formula have the same meaning as in steps 405 and 603. The formula is linearized using the methods described in steps 405 and 603, and the Kalman filter algorithm is used to solve the equation to obtain the user's position at the corresponding time. If needed... The position of the time is calculated using the method in step 405.

[0040] If the above process fails to locate the target, return to step 703 to continue execution.

[0041] Example 5 Figure 5 A schematic diagram of a positioning device structure according to Embodiment 5 of the present invention is shown. The specific embodiments of the present invention do not limit the specific implementation of the electronic device.

[0042] like Figure 5 As shown, the positioning device includes: a measurement signal receiving module, an inertial navigation module, a time and frequency module, and a calculation module.

[0043] The measurement signal receiving module is used to receive measurement signals that match the beacon's transmitted signals, and at the same time generate corresponding observations for receiving and analyzing the beacon's position and clock error; The inertial navigation module is used to output the change in the terminal position at the current observation time relative to the previous observation time. The time and frequency module is equipped with a highly stable clock to provide time and frequency information to both the receiving module and the inertial navigation module. The computing module includes a signal processing unit, a data processing unit, a storage unit, and various communication interfaces, which can perform corresponding operations.

[0044] Furthermore, the beacon can be a GNSS navigation satellite, or any device or apparatus capable of transmitting measurement signals. As long as the user terminal can receive the measurement signals, the position and movement state of the beacon can be arbitrary and without specific restrictions.

[0045] Furthermore, the measured values ​​generated based on the measurement signal are not subject to excessive restrictions on the signal transmission frequency and bandwidth, as long as the measurement signal matches the user terminal; the measured value can be a separate pseudorange measurement value, and the standard deviation of the measurement error is... A single Doppler measurement can be a pseudorange measurement or a Doppler measurement. At the same time, the carrier phase measurement must appear in pairs with the pseudorange measurement (in the following methods, the carrier phase measurement can be received or not).

[0046] Furthermore, the calculated or acquired position and time of the beacon's transmission measurement signal are based on the same spatiotemporal coordinate system for all beacons. If deviations exist, they can be restored to the same spatiotemporal coordinate system using known corrections. Simultaneously, the standard deviation of the error in the beacon's position and time can be obtained statistically or by calculation. .

[0047] Furthermore, the highly stable clock, within a certain time period... Clock speed stability ( It is determined by the stability of the user's received clock, and in The clock error variation (maximum clock error - minimum clock error) within a time period is in the range of nanoseconds or less, or it can be corrected by a certain coefficient or method to control the clock error variation to be in the range of nanoseconds or less.

[0048] Furthermore, the inertial navigation device maintains a time frequency that is completely consistent with the time frequency at which the measurement value is generated, and the measurement value at the current moment and the measurement value at the previous moment can be generated by different beacon signals.

[0049] This application provides a computer-readable storage medium storing computer instructions that, when executed on a computer, cause the computer to perform... Figure 1 The method described.

[0050] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0051] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0052] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0053] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0054] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A positioning method based on sparse measurement signals, characterized in that, include: Receive measurement signals from one or more beacons and generate measurement values; Obtain the position and time information of the beacon transmitting the measurement signal corresponding to each measurement value; Obtain the location change information of the user terminal when generating each measurement value; The user location and receiver clock error corresponding to the measurement values ​​at different times are reduced to the same reference time based on the location change information and clock error stability; Using the reduced user location and receiver clock error, along with the measured values, a positioning equation is constructed; Solve the positioning equation to obtain the user's position and clock difference at the reference time.

2. The positioning method based on sparse measurement signals according to claim 1, characterized in that, The measured values ​​are sparse pseudorange measurements. The steps of the localization method based on sparse pseudorange measurements include: Step 201: The user terminal receives the beacon measurement signal and generates pseudorange measurement value. The inertial navigation system outputs the position change at the corresponding time. If more than or equal to the pseudorange measurement value of four beacons is obtained at the same time, proceed to step 202. If no more than or equal to the measurement value of four beacons is obtained, proceed to step 203. Step 202: The user calculates or obtains the position and clock difference when the beacon transmits the measurement signal, eliminates various error sources contained in the measurement value, and calculates the user's position at the current time; Step 203: The user continues to receive measurement values ​​until four or more measurement values ​​are received. The user's desired positioning accuracy is... Evaluate the PDOP value of the localization equation at this point. If the received value is less than the given value, then the system will continue to receive measurement values. If the value is less than the given value, the system will use the received N pseudorange measurement values ​​for positioning. This represents the standard deviation of the beacon's position and time error. N represents the standard deviation of the pseudorange measurement error; N is a positive integer. Step 204, if the waiting period for the measurement value exceeds... If the PDOP value of the positioning equation still cannot meet the condition of step 203 after a certain number of seconds, the calculation will restart from the second measurement time. If the time period exceeds a certain threshold... If the time interval is still insufficient, the calculation will restart from the third measurement time, and so on.

3. The positioning method based on sparse measurement signals according to claim 2, characterized in that, The evaluation of the PDOP value of the localization equation includes: Step 301: Obtain N pseudorange measurements. and N-1 position change vectors ; Step 302, using the origin of the coordinate system Using the position change vector as a reference point, the position at time T corresponding to the last time moment is obtained. The calculation method is as follows: in, Represents the accumulation of vectors; Step 303, using the obtained N-1 and reference origin And the location of the beacon at each time point, according to Calculate the corresponding PDOP value; where, The trace of the matrix, ; Indicates the reference origin To the Known points The direction cosine.

4. The positioning method based on sparse measurement signals according to claim 3, characterized in that, Methods for positioning using N received pseudorange measurements include: Step 401: Obtain N pseudorange measurements. The position and time of N beacon transmission measurement signals, N local clock times, and N-1 position change vectors. The user's location at each moment is as follows: Furthermore, the user's location is unknown. Step 402, assuming the user needs Location at any moment Using the known position change vector , will other User location at any given time is calculated to The time is calculated as follows: ； Step 403, assuming the terminal clock difference at each measurement reception time is... Furthermore, since the terminal clock bias is unknown, the clock bias variation is corrected to below nanoseconds, effectively making the receiver clock bias over the entire time period equivalent to a constant value. ; Step 404: Add the position correction error and clock error to the measurement error: In the formula, It is the standard deviation of the original measurement error. It is the standard deviation of the measurement error of the inertial navigation system, determined according to the inertial navigation system. It is the standard deviation of the error after the terminal clock bias is reduced. It is the standard deviation of the error of the new measurement value; Step 405, the equation composed of the received N observations can be expressed as: In the formula, express The location of the time beacon, and the location of the user terminal at each time. Transform to step 402 Terminal clock difference at each moment Transform to step 403 The above equation is linearized using a Taylor expansion, and then solved using the iterative least squares method to obtain the position at time t. The method for calculating its position at time T is as follows: 。 5. The positioning method based on sparse measurement signals according to claim 1, characterized in that, The measured values ​​are sparse Doppler measurements; The steps of the localization method based on sparse Doppler measurements include: Step 501: The user terminal receives the beacon measurement signal and generates Doppler measurement values. The inertial navigation system outputs the position change at the corresponding time. If more than four Doppler measurement values ​​are received, proceed to step 502; otherwise, continue receiving measurement values. Step 502: Use the received N Doppler measurements to locate the position. If the positioning results converge, the positioning is complete; otherwise, continue to step 503. Step 503, continue receiving Doppler measurements. If the difference between the measured values ​​at different times is within... Within seconds, all observations are used to continue positioning based on step 502; if more than that... If the time interval exceeds a certain number of seconds, the calculation will restart from the second measurement time. If the positioning convergence is not achieved in step 502, the calculation will restart from the third measurement time, and so on.

6. The positioning method based on sparse measurement signals according to claim 5, characterized in that, Methods for localization using N received Doppler measurements include: Step 601: Obtain N Doppler measurements. The positions and times of N beacon transmission measurement signals, N local receiver times, and N-1 position change vectors. The user's location at each moment is as follows: And the user's location is unknown; Step 602: Reuse step 402 to calculate the position, and convert the clock drift during this period into a constant value. ; Step 603, the relationship between the frequency of the N Doppler measurements received by the user at each moment and the satellite transmission frequency is as follows: In the above formula, It is the satellite's speed relative to the user at each moment. To measure the original frequency of the signal, Zhong Piao, It's the speed of light. It is the user location that needs to be calculated. express The position of the beacon at time; its linear representation using Taylor expansion, and the solution to this equation to obtain the user's position at the corresponding time; the calculation using the method in step 405. The position at that moment; If the above process fails to achieve positioning, return to step 503 to continue execution.

7. The positioning method based on sparse measurement signals according to claim 1, characterized in that, The measured values ​​include both sparse pseudorange values ​​and Doppler measurements; The steps of the localization method based on sparse pseudorange values ​​and Doppler measurements include: Step 701: The user terminal receives the beacon measurement signal and generates pseudorange and Doppler measurement values. The inertial navigation system outputs the position change at the corresponding time. If more than four pseudorange measurement values ​​and corresponding Doppler measurement values ​​are received, step 702 is executed; otherwise, the measurement values ​​are received. Step 702: Use the received N pseudorange and Doppler measurements to perform positioning. If the positioning results converge, the positioning is complete; otherwise, continue to step 703. Step 703, continue receiving pseudorange and Doppler measurements. If the difference between the measured values ​​at any given time is within... If within seconds, then all observations are used to continue positioning based on step 702; if it exceeds... If the time interval exceeds a certain number of seconds, the calculation will restart from the second measurement point. If the positioning convergence is not achieved in step 702, the calculation will restart from the third measurement time, and so on.

8. The positioning method based on sparse measurement signals according to claim 7, characterized in that, Methods for localization using N received pseudoranges and Doppler measurements include: Step 801: Obtain N pseudorange measurements. N Doppler measurements The positions and times of N beacon transmission measurement signals, N local receiver times, and N-1 position change vectors. The user's location at each moment is as follows: Furthermore, the user's location is unknown. Step 802: Repeat step 402 to correct the position, and repeat step 403 to correct the clock error. The receiver clock error is equivalent to a constant value throughout the entire time period. The clock's movement during this period is equivalent to a constant value. ; Step 803, the equation composed of the received N pseudorange observations and Doppler observations is expressed as: Represent it linearly and solve the equation to obtain the user's position at the corresponding time; if needed The position of the time is calculated using the method in step 405; If the above process fails to locate the target, return to step 703 to continue execution.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 8.

10. A positioning device based on sparse measurement signals, characterized in that, include: The measurement signal receiving module is used to receive measurement signals that match the beacon's transmitted signals and generate corresponding observations for receiving and analyzing the beacon's position and clock error. The beacon is a GNSS navigation satellite or any device or apparatus capable of transmitting measurement signals. The measurement signals are matched with the user terminal where the positioning device is located, and there are no restrictions on its signal transmission frequency and bandwidth. The measurements are either a single pseudorange measurement, a single Doppler measurement, or a pseudorange measurement and a Doppler measurement, while the carrier phase measurement appears in pairs with the pseudorange measurement. The inertial navigation module is used to output the change of the terminal position at the current observation time relative to the previous observation time; it calculates or acquires the position and time of the beacon transmitting the measurement signal. For all beacons, their position and time are in the same spatiotemporal coordinate system. If there is a deviation, it is restored to the same spatiotemporal coordinate system by a known correction amount. At the same time, the standard deviation of the error of the beacon's position and time can be obtained by statistics or calculation. The time-frequency module, equipped with a clock, provides time-frequency information to both the receiving module and the inertial navigation module; within a certain time period... The clock speed is stable, and in The clock error variation within the time period is in the range of nanoseconds or less, or it is corrected by a certain coefficient or method to control the clock error variation to be in the range of nanoseconds or less; the time frequency of the inertial navigation equipment is consistent with the time frequency of the measurement value generation. A calculation module for performing the operations of the method described in any one of claims 1 to 8.

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