Multi-directional fusion post-processing positioning method and device

Abstract

The application provides a multi-directional fusion post-processing positioning method and device, the method comprising: obtaining observation data of N epochs; performing first round forward filtering calculation based on the observation data of the N epochs; in the second round enhanced reverse filtering calculation, for each epoch, taking the calculation result of the first round forward filtering calculation of the epoch as input data to deeply fuse the ambiguity and improve the success rate of ambiguity fixing in the enhanced reverse filtering calculation; in addition, a new round of enhanced forward filtering calculation is added, for each epoch, taking the calculation result obtained by the enhanced reverse filtering calculation as input data to deeply fuse the ambiguity again and improve the success rate of ambiguity fixing in the current round of enhanced forward filtering calculation; in this way, more epochs are allowed to fix the ambiguity as much as possible, and then the fixed ambiguity calculation obtained by the enhanced forward and reverse filtering calculation is used to obtain the fixed solution, thereby improving the PPK positioning accuracy and reliability.

Description

Technical Field

[0001] This application relates to the field of positioning technology, and in particular to a multi-directional fusion post-processing positioning method and apparatus. Background Technology

[0002] With the rapid development and continuous improvement of Global Navigation Satellite System (GNSS) technology, it has been widely used in various fields. Post-Processed Kinematic (PPK) is a relative positioning technology that accurately calculates the rover's position by post-processing acquired rover and base station observation data. Compared with the widely used Real-Time Kinematic (RTK) technology, PPK does not require real-time differential data and its calculation method can fuse the results from consecutive epochs, resulting in higher accuracy and reliability. Currently, the fusion of PPK technology with Inertial Navigation System (INS) post-processing results is often used as a reference for high-precision positioning and attitude determination. It can be used to evaluate the real-time positioning and attitude determination performance of GNSS / IMU modules and provide accurate and reliable post-processed position and attitude information for UAV aerial surveying and high-precision map acquisition.

[0003] Currently, the PPK algorithm performs a forward filtering calculation based on the observed data, followed by a reverse filtering calculation, and then fuses the results to obtain the final PPK positioning result. Traditional methods of smoothing the positioning result through simple forward and reverse filtering fusion offer limited improvement in positioning accuracy. For example, if both forward and reverse calculations at a certain epoch produce floating-point solutions, then no amount of smoothing will achieve the accuracy of a fixed solution. Therefore, how to perform deep fusion to improve PPK positioning accuracy is a pressing issue that needs to be addressed. Summary of the Invention

[0004] This application provides a post-processing positioning method and apparatus for multi-directional fusion. By enhancing the inverse filtering solution with the result of the forward filtering solution based on the existing forward and reverse filtering fusion, and introducing a new round of enhanced forward solution, more epochs can be fixed with double difference ambiguity through three rounds of solution, thereby obtaining a PPK positioning result with higher positioning accuracy.

[0005] Firstly, this application provides a multi-directional fusion post-processing localization method, comprising: Obtain observation data for N epochs; N is a positive integer greater than 1; Along a first direction, for each epoch, a first solution operation is performed based on the observation data of that epoch to obtain a first solution result for that epoch; the first direction is the direction from the 1st epoch to the Nth epoch; the first solution result includes: the first position of the rover, the solution state of the first position, and the solution error of the first position; some operations of the first solution operation are: a first ambiguity update operation, a first double-difference floating-point filtering solution operation, and a first ambiguity fixing operation; the first ambiguity update operation is used to maintain ambiguity recursively based on the double-difference ambiguity of the previous epoch in the first direction; the first double-difference floating-point filtering solution operation is used to estimate the first candidate position of the rover and the first floating-point double-difference ambiguity based on the observation data of that epoch; the first ambiguity fixing operation is used to fix the first floating-point double-difference ambiguity; the results of the first ambiguity update operation and the first ambiguity fixing operation are fused to obtain a first ambiguity set; the first position is updated based on the first ambiguity set to obtain the first candidate position; Along the second direction, for each epoch, a second solution operation is performed based on the first solution result of the epoch and the observation data of the epoch to obtain the second solution result of the epoch; the second direction is the direction from the Nth epoch to the 1st epoch; the second solution result includes the second position of the rover, the solution state of the second position, and the solution error of the second position; some operations of the second solution operation are: a second ambiguity update operation, a second double-difference floating-point solution filtering calculation, a second ambiguity fixing operation, and a first auxiliary ambiguity fusion operation; the second ambiguity update operation is used to perform ambiguity recursion based on the double-difference ambiguity of the previous epoch in the second direction. The process is as follows: The second double-difference floating-point filtering operation is used to estimate the second candidate position and the second floating-point double-difference ambiguity of the rover station based on the observation data of the epoch; the second ambiguity fixing operation is used to fix the second floating-point double-difference ambiguity; the first auxiliary ambiguity fusion operation is used to determine whether the epoch has a first prior fixed ambiguity based on the first solution result; the results of the second ambiguity update operation, the second ambiguity fixing operation, and the first auxiliary ambiguity fusion operation are ambiguity fused to obtain a second ambiguity set; the second position is updated based on the second ambiguity set to obtain the second candidate position; Along the first direction, for each epoch, a third solution operation is performed based on the second solution result of the epoch and the observation data of the epoch to obtain the third solution result of the epoch; the third solution result includes the third position of the rover, the solution state of the third position, and the solution error of the third position; some operations of the third solution operation are: a third ambiguity update operation, a third double-difference floating-point solution filtering solution, a third ambiguity fixing operation, and a second auxiliary ambiguity fusion operation; the third ambiguity update operation is used to maintain ambiguity recursively based on the double-difference ambiguity of the previous epoch in the first direction; the third double-difference floating-point solution... The filtering operation is used to estimate the third candidate position and the third floating-point double-difference ambiguity of the rover station based on the observation data of the epoch; the third ambiguity fixing operation is used to fix the third floating-point double-difference ambiguity; the second auxiliary ambiguity fusion operation is used to determine whether there is a second prior fixed ambiguity in the epoch based on the second solution result; the ambiguity fusion of the result of the third ambiguity update operation, the result of the third ambiguity fixing operation, and the result of the second auxiliary ambiguity fusion operation is performed to obtain a third ambiguity set; the third position is updated based on the third ambiguity set to obtain the third candidate position; For each of the N epochs, the second solution result and the third solution result of the epoch are fused to obtain the post-processing positioning result of the rover in the epoch.

[0006] Secondly, this application provides a multi-directional fusion post-processing positioning apparatus, comprising: a module for executing the multi-directional fusion post-processing positioning method described in the first aspect.

[0007] Thirdly, this application provides an electronic device, including: a memory and a processor; The memory is configured to store computer program instructions; The processor is configured to execute the computer program instructions, causing the electronic device to implement the method described in the first aspect.

[0008] Fourthly, this application provides a readable storage medium, including: computer program instructions; At least one processor of the electronic device executes the computer program instructions, causing the electronic device to implement the method described in the first aspect.

[0009] Fifthly, this application provides a computer program product, which an electronic device runs to enable the electronic device to implement the method described in the first aspect.

[0010] In a sixth aspect, this application provides a chip, comprising: an interface circuit and a logic circuit, wherein the interface circuit is configured to receive signals from other chips outside the chip and transmit them to the logic circuit, or to send signals from the logic circuit to other chips outside the chip, and the logic circuit is configured to implement the method described in the first aspect.

[0011] This application provides a multi-directional fusion post-processing positioning method and apparatus. The method uses a "forward filtering solution + enhanced reverse filtering solution + enhanced forward filtering solution" approach to enable more epochs to fix ambiguities. Then, a fixed solution is obtained based on the fixed ambiguity solution obtained by the enhanced forward and reverse filtering solutions, thereby improving the positioning accuracy and reliability of PPK. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of a positioning system provided in an embodiment of this application; Figure 2 Here is a flowchart of the existing PPK algorithm; Figure 3 A flowchart illustrating a post-processing localization method for multi-directional fusion provided in an embodiment of this application; Figure 4 A flowchart of a multi-directional fusion post-processing localization method provided in another embodiment of this application; Figure 5 A flowchart illustrating the first solution operation provided in an embodiment of this application; Figure 6 A flowchart illustrating the processing of the second solution operation provided in an embodiment of this application; Figure 7 A flowchart illustrating the processing of the third solution operation provided in an embodiment of this application; Figure 8 A schematic diagram of a fuzzy fusion process provided in an embodiment of this application; Figure 9 A structural diagram of a multi-directional fusion post-processing apparatus provided in an embodiment of this application; Figure 10 This is a structural diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0013] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c alone can mean: a alone, b alone, c alone, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0014] The terms “center,” “longitudinal,” “lateral,” “up,” “down,” “left,” “right,” “front,” and “rear,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0015] The terms "connected" and "connected" should be interpreted broadly. For example, in circuit structures, "connected" or "connected" can refer not only to physical connections but also to electrical or signal connections. This could be a direct connection (physical connection) or an indirect connection via at least one intermediate component, as long as the circuit is connected. It could also refer to the internal connection between two components. Similarly, a signal connection can refer to a connection via a circuit or a medium, such as radio waves. Those skilled in the art will understand the specific meaning of these terms in this application based on the specific circumstances.

[0016] Figure 1 This is a structural diagram of a positioning system provided in one embodiment of this application. Please refer to [link / reference]. Figure 1 The positioning system 10 can be one or more of the following positioning systems: Global Positioning System (GPS), BeiDou Navigation Satellite System (BDS), GLONASS, and Galileo.

[0017] The positioning system 10 includes: multiple satellites 11, a base station 12, and a rover 13.

[0018] Multiple satellites 11 constitute the space segment of the positioning system. This application does not limit the number of satellites 11; multiple satellites 11 can be distributed across different orbital planes to continuously and uninterruptedly broadcast satellite signals to all users worldwide. Satellite signals may also be referred to as satellite navigation signals or other names.

[0019] Reference station 12 is generally a fixed ground observation station used to observe satellite signals transmitted by satellite 11. Reference station 12 is fixed at a known reference position. Reference station 12 is equipped with a receiver capable of receiving satellite signals and generating reference station observation data based on the satellite signals.

[0020] The mobile station 13 is a mobile positioning terminal and can be an electronic device such as an airplane, ship, vehicle, smartphone, laptop, or vehicle-mounted terminal. The mobile station 13 can be stationary or in motion.

[0021] In some scenarios, the base station 12 can continuously receive satellite signals from all visible satellites to generate base station observation data, and send the base station observation data and base station position information to the rover 13. At the same time, the rover 13 will also collect rover observation data. Then, the rover 13 uses the base station observation data and the rover observation data to perform positioning calculations.

[0022] In other scenarios, the positioning system 10 also includes a multi-directional fusion post-processing positioning device 14 (hereinafter referred to as the post-processing positioning device), which can be connected to the base station 12 and the rover 13 via wired or wireless means. The base station 12 and the rover 13 can transmit their respective observation data to the post-processing positioning device 14 for positioning calculation. The post-processing positioning device 14 can be, but is not limited to, a server, a cloud server, or a server cluster.

[0023] Figure 2 This is a flowchart of the PPK algorithm in the prior art. The rover 13 or the post-processing positioning device 14 first performs a forward filtering calculation from the 1st epoch to the Mth epoch; that is, for each epoch, a forward calculation operation is performed based on the observation data of that epoch to obtain the forward calculation result for that epoch. Then, a reverse filtering calculation is performed from the Mth epoch to the 1st epoch; that is, for each epoch, a calculation operation is performed based on the observation data of that epoch to obtain the reverse calculation result for that epoch. Next, for each epoch, the forward and reverse calculation results are fused to obtain the post-processing positioning result for that epoch.

[0024] Figure 2The PPK algorithm shown smooths the positioning results through simple forward and reverse filtering. However, because the results of the forward filtering are not fully utilized in the reverse filtering process, the improvement in positioning accuracy by the existing PPK algorithm is limited. Therefore, optimizing the existing PPK algorithm to fix ambiguities in more epochs, thereby significantly improving the positioning accuracy and reliability of PPK, is a pressing issue that needs to be addressed.

[0025] To address the aforementioned issues, this application provides a multi-directional fusion post-processing positioning method, apparatus, electronic device, readable storage medium, chip, and computer program product. This application proposes a multi-directional fusion post-processing positioning method consisting of "forward filtering solution + enhanced reverse filtering solution + enhanced forward filtering solution," aiming to fix ambiguity in as many epochs as possible to improve PPK positioning accuracy and reliability.

[0026] Figure 3 A flowchart of the multi-directional fusion post-processing localization method provided in this application. Please refer to [link / reference]. Figure 3 As shown, the first round of forward filtering is performed and Figure 2 The first round of forward filtering in the PPK algorithm is similar to the previous one. In the second round of reverse filtering, for each epoch, the result of the first round of forward filtering is used as input data. The result of the forward filtering is used to perform deep fusion of ambiguities, thereby enhancing the reverse filtering and improving the success rate of fixing ambiguities in this round of reverse filtering. Furthermore, this application adds a new round of forward filtering after the second round of enhanced reverse filtering. The result of the second round of reverse filtering is used as input data, and the result of the enhanced reverse filtering is used to perform deep fusion of ambiguities, thereby enhancing the forward filtering and improving the success rate of fixing ambiguities in this round of forward filtering. In this way, as many epochs as possible can fix ambiguities, thereby improving the positioning accuracy and reliability of PPK.

[0027] The second round of inverse filtering is equivalent to enhanced inverse filtering; the third round of forward filtering is equivalent to enhanced forward filtering.

[0028] The multi-directional fusion post-processing positioning method provided in this application has the advantages of simple implementation logic, high solution fixation rate, and reliable accuracy. It can effectively improve the positioning performance of PPK in occluded environments and has high practical value in applications such as mobile mapping and high-precision position reference systems.

[0029] Next, the multi-directional fusion post-processing positioning method provided in this application will be described in detail with reference to several accompanying drawings and specific embodiments. It should be noted that the following embodiments use the execution of the multi-directional fusion post-processing positioning method provided in this application by a post-processing positioning device as an example for detailed explanation.

[0030] Combination Figure 3 As described above, this application relates to forward filtering, enhanced inverse filtering, and enhanced forward filtering. In the forward filtering, a first calculation operation is performed for each epoch, and the operation flow of the first calculation operation is as follows: Figure 5 As shown; in the enhanced inverse filtering solution, a second solution operation is performed for each epoch. The operation flow of the second solution operation is as follows: Figure 6 As shown; in the enhanced forward filtering solution, a third solution operation is performed for each epoch. The operation flow of the third solution operation is as follows: Figure 7 As shown.

[0031] Figure 4 This is a flowchart illustrating a multi-directional fusion post-processing localization method provided in one embodiment of this application. Please refer to... Figure 4 As shown, the method in this embodiment includes: S401. Obtain observation data for N epochs, where N is a positive integer greater than 1.

[0032] An epoch refers to the moment when observation data is acquired.

[0033] The observation data for each epoch includes: base station observation data, rover station observation data, and ephemeris data. The base station observation data may include pseudorange observation data, carrier phase observation data, and Doppler observation data calculated by the base station based on received satellite signals. The rover station observation data may also include pseudorange observation data, carrier phase observation data, and Doppler observation data calculated by the rover station based on received satellite signals. Ephemeris data is a set of parameters broadcast by each satellite regarding its position in space; based on these parameters, the precise position of the satellite in space over a period of time can be accurately calculated.

[0034] S402. Along the first direction, for each epoch, perform the first solution operation based on the observation data of the epoch to obtain the first solution result of the epoch. The first solution result includes: the first position of the rover, the solution state of the first position, and the solution error of the first position.

[0035] The first direction refers to the direction from the 1st epoch to the Nth epoch, which is the "positive direction" involved in this application.

[0036] Please see Figure 5 As shown, the first solution operation includes: single-point positioning operation, first quality control operation, first ambiguity update operation, first double-difference floating-point defiltering solution operation, first ambiguity fixing operation, first ambiguity fusion operation, and first positioning result output operation.

[0037] Performing a single-point localization operation yields the single-point localization result of the rover. This result can be used as the final localization result of the rover in cases where ambiguity update or ambiguity fixing fails.

[0038] Performing the first quality control operation can identify and mark observation data with errors.

[0039] Performing the first ambiguity update operation determines whether the fixed double-difference ambiguity of the previous epoch can be maintained in the current epoch along the first direction. Therefore, the first ambiguity update operation can also be understood as an ambiguity recursive maintenance operation. It should be noted that if the double-difference ambiguity of the previous epoch is not a fixed ambiguity, such as a floating-point double-difference ambiguity, then the ambiguity of the previous epoch cannot be maintained in the current epoch.

[0040] Performing the first double-difference floating-point solution filtering operation can estimate a rover position (first candidate position) and floating-point double-difference ambiguity based on the base station observation data and the rover observation data.

[0041] Performing the first ambiguity fixing operation can search and determine whether the estimated floating-point double-difference ambiguity can be fixed.

[0042] Performing the first fuzziness fusion operation can fuse the results of performing the first fuzziness update operation and the results of performing the first fuzziness fixation operation to obtain the first fuzziness set.

[0043] The first positioning result output operation can update the estimated rover position (i.e. the first candidate position) based on the first ambiguity set, obtain the first position of the rover, and determine the first position calculation error.

[0044] The larger the error in the first position calculation, the lower the positioning accuracy of the calculated first position; the smaller the error in the first position calculation, the higher the positioning accuracy of the calculated first position.

[0045] S403. Along the second direction, for each epoch, perform a second solution operation based on the first solution result of the epoch and the observation data of the epoch to obtain the second solution result of the epoch. The second solution result includes: the second position of the rover, the solution state of the second position, and the solution error of the second position.

[0046] The second direction is the direction from the Nth epoch to the 1st epoch, which is the "reverse direction" involved in this application.

[0047] Please see Figure 6As shown, the second solution operation includes: single-point positioning operation, first auxiliary quality control operation, second ambiguity update operation, second double-difference floating-point solution filtering operation, second ambiguity fixing operation, first auxiliary ambiguity fusion operation, second ambiguity fusion operation, and second positioning result output operation.

[0048] The single-point positioning operation, the second ambiguity update operation, the second double-difference floating-point solution filtering operation, the second ambiguity fixing operation, and the second positioning result output operation in the second solution operation are similar to the first ambiguity update operation, the first double-difference floating-point solution filtering operation, the first ambiguity fixing operation, and the first positioning result output operation in the first solution operation mentioned above, and will not be described again here.

[0049] The first auxiliary quality control operation in the second solution operation identifies and marks observational data with errors based on the first position in the first solution result and the observational data at the current epoch. This achieves quality control at the epoch using the first solution result. Compared to the first quality control operation, the first auxiliary quality control operation adds the first position from the first solution result at the epoch as prior position information to the input data, helping to identify observational data with errors and thus improving the quality control effect.

[0050] Among them, the first auxiliary fuzzyness fusion operation in the second solution operation is mainly used to determine whether there is a first prior fixed fuzzyness in the current epoch based on the first solution result.

[0051] In some embodiments, the post-processing positioning device can first determine whether the solution state of the first position in the current epoch is a fixed solution. If it is not a fixed solution, such as a floating-point solution, pseudorange difference decomposition, or single-point solution, then it is determined that there is no first prior fixed ambiguity in the current epoch. If it is a fixed solution, then it is determined whether the solution error of the first position is less than a preset error threshold. If it is greater than or equal to, then it is determined that there is no first prior fixed ambiguity in the current epoch. If it is less than, then it indicates that the first position is reliable. Then, based on the first position of the current epoch and the observation data of the current epoch, the double-difference carrier ambiguity of the current epoch (which can be understood as auxiliary double-difference fixed ambiguity) is calculated. Then, by checking the consistency of the integer characteristics of the double-difference carrier ambiguity of all satellites, if the ambiguity integer consistency is satisfied, then it is determined that there is a first prior fixed ambiguity in the current epoch. The first prior fixed ambiguity is the auxiliary fixed double-difference ambiguity of the current epoch calculated by the post-processing positioning device based on the first position of the current epoch and the observation data of the current epoch.

[0052] In other embodiments, the post-processing positioning device can first determine whether the solution state of the first position in the current epoch is a fixed solution. If it is not a fixed solution, for example, a floating-point solution, pseudorange difference decomposition, or single-point solution, then it is determined that there is no first prior fixed ambiguity in the current epoch. If it is a fixed solution, the post-processing positioning device calculates the double-difference carrier ambiguity of the current epoch based on the first position and the observation data of the current epoch. Then, it determines whether the calculated double-difference carrier ambiguity of all satellites satisfies the integer characteristic consistency and whether the solution error of the first position in the current epoch is less than a preset error threshold. If either of these conditions is not met, i.e., the entire... If the double-difference carrier ambiguity of some satellites does not satisfy the integer characteristic consistency (also known as ambiguity integer consistency), and / or the first position calculation error is greater than or equal to a preset error threshold, then it is determined that there is no first prior fixed ambiguity in the current epoch; conversely, if the double-difference carrier ambiguity of all satellites satisfies the integer characteristic consistency, and the first position calculation error in the current epoch is less than the preset error threshold, then it is determined that there is a first prior fixed ambiguity in the current epoch, and the first prior fixed ambiguity is the auxiliary fixed double-difference ambiguity of the current epoch calculated by the post-processing positioning device based on the first position of the current epoch and the observation data of the current epoch.

[0053] The preset error threshold can be set based on experience, and this application does not limit the size of the preset error threshold.

[0054] In addition, the post-processing device can also adjust the judgment logic of the first auxiliary fuzziness fusion operation. For example, it can first determine whether the first position solution error is less than a preset error threshold, and then determine whether the solution state of the first position is a fixed solution.

[0055] The second fuzzy fusion operation merges the results of the second fuzzy update operation, the second fuzzy fixation operation, and the first auxiliary fuzzy fusion operation to obtain a second fuzzy set. Compared to the first fuzzy fusion operation, the second fuzzy fusion operation processes more fuzzy data, thereby increasing the probability of obtaining a fixed solution in each epoch.

[0056] The second positioning result output operation can update the estimated rover position based on the second ambiguity set, obtain the second position of the rover, and determine the second position calculation error.

[0057] Similarly, the larger the error in the second position calculation, the lower the positioning accuracy of the calculated second position; the smaller the error in the second position calculation, the higher the positioning accuracy of the calculated first position.

[0058] S404. Along the first direction, for each epoch, a third solution operation is performed based on the second solution result of the epoch and the observation data of the epoch to obtain the third solution result of the epoch. The third solution result includes: the third position of the rover, the solution state of the third position, and the solution error of the third position.

[0059] Please see Figure 7 As shown, the third solution operation includes: single-point positioning operation, second auxiliary quality control operation, third ambiguity update operation, third double-difference floating-point solution filtering operation, third ambiguity fixing operation, second auxiliary ambiguity fusion operation, third ambiguity fusion operation, and third positioning result output operation.

[0060] The single-point positioning operation, the third ambiguity update operation, the third double-difference floating-point solution filtering operation, the third ambiguity fixing operation, and the third positioning result output operation in the third solution operation are similar to the first ambiguity update operation, the first double-difference floating-point solution filtering operation, the first ambiguity fixing operation, and the first positioning result output operation in the first solution operation mentioned above, and will not be described again here.

[0061] The second auxiliary quality control operation in the third solution operation identifies and marks observational data with errors based on the second position in the second solution result and the observational data at the current epoch. This achieves quality control at the epoch using the second solution result. Compared with the first quality control operation, the second auxiliary quality control operation adds the second position from the second solution result at the epoch as prior position information to the input data, helping to identify observational data with errors and thus improving the quality control effect.

[0062] Among them, the second auxiliary fuzzyness fusion operation in the third solution operation is mainly used to determine whether there is a second prior fixed fuzzyness in the current epoch based on the second solution result.

[0063] In some embodiments, the post-processing positioning device can first determine whether the solution state of the second position in the current epoch is a fixed solution. If it is not a fixed solution, such as a floating-point solution, pseudorange difference decomposition, or single-point solution, then it is determined that there is no second prior fixed ambiguity in the current epoch. If it is a fixed solution, then it is determined whether the second position calculation error is less than a preset error threshold. If it is greater than or equal to, then it is determined that there is no second prior fixed ambiguity in the current epoch. If it is less than, then it indicates that the second position is reliable. Then, based on the second position of the current epoch and the observation data of the current epoch, the double-difference carrier ambiguity of the current epoch (which can be understood as auxiliary double-difference fixed ambiguity) is calculated. Then, by checking the consistency of the integer characteristics of the double-difference carrier ambiguity of all satellites, if the ambiguity integer consistency is satisfied, then it is determined that there is a second prior fixed ambiguity in the current epoch. The second prior fixed ambiguity is the auxiliary fixed double-difference ambiguity of the current epoch calculated by the post-processing positioning device based on the second position of the current epoch and the observation data of the current epoch.

[0064] In other embodiments, the post-processing positioning device can first determine whether the solution state of the second position in the current epoch is a fixed solution. If it is not a fixed solution, for example, a floating-point solution, pseudorange difference decomposition, or single-point solution, then it is determined that there is no second prior fixed ambiguity in the current epoch. If it is a fixed solution, the post-processing positioning device calculates the double-difference carrier ambiguity of the current epoch based on the second position and the observation data of the current epoch. Then, it determines whether the calculated double-difference carrier ambiguity of all satellites satisfies the integer characteristic consistency and whether the second position solution error of the current epoch is less than a preset error threshold. If either of these conditions is not met, i.e., the entire... If the double-difference carrier ambiguity of some satellites does not satisfy the integer characteristic consistency (also known as ambiguity integer consistency), and / or the second position calculation error is greater than or equal to a preset error threshold, then it is determined that there is no second prior fixed ambiguity in the current epoch; conversely, if the double-difference carrier ambiguity of all satellites satisfies the integer characteristic consistency, and the second position calculation error in the current epoch is less than the preset error threshold, then it is determined that there is a second prior fixed ambiguity in the current epoch, and the second prior fixed ambiguity is the auxiliary fixed double-difference ambiguity of the current epoch calculated by the post-processing positioning device based on the second position of the current epoch and the observation data of the current epoch.

[0065] The preset error threshold can be set based on experience, and this application does not limit the size of the preset error threshold.

[0066] Furthermore, the preset error thresholds used for the first auxiliary fuzziness fusion operation and the second auxiliary fuzziness fusion operation can be the same or different, and this application does not limit this.

[0067] In addition, the post-processing device can also adjust the judgment logic of the second auxiliary fuzziness fusion operation. For example, it can first determine whether the second position solution error is less than a preset error threshold, and then determine whether the solution state of the second position is a fixed solution.

[0068] The third fuzziness fusion operation fuses the results of the third fuzziness update operation, the third fuzziness fixation operation, and the second auxiliary fuzziness fusion operation to obtain a third fuzzy set. Compared with the first fuzziness fusion operation, the third fuzziness fusion operation processes more objects, that is, it fuses more fuzzy data, thereby increasing the probability of obtaining a fixed solution in an epoch.

[0069] The third positioning result output operation can update the estimated rover position based on the third ambiguity set, obtain the third position of the rover, and determine the third position calculation error.

[0070] Similarly, the larger the error in the third position calculation, the lower the positioning accuracy of the calculated third position; the smaller the error in the third position calculation, the higher the positioning accuracy of the calculated third position.

[0071] S405. For each of the N epochs, the second and third solution results of the epoch are fused to obtain the post-processing positioning result of the rover at the epoch.

[0072] The post-processing positioning device can compare whether the solution states contained in the second and third solution results are the same, and then use different fusion methods to fuse the second and third solution results of each epoch.

[0073] In some embodiments, if the solution states contained in the second and third solution results are the same, then the second and third positions are weighted and summed according to the second and third position solution errors to obtain the post-processing positioning result of the rover. The second position solution error corresponds to the weighting coefficient of the second position, and the third position solution error corresponds to the weighting coefficient of the third position. For example, if the solution states contained in both the second and third solution results are fixed solutions, the second position solution error is 0.2, the second position is (x2, y2), and the third position solution error is 0.1, the third position is (x3, y3). Then, by weighting, the post-processing positioning result (X, Y) = ((x2, y2) / 0.2 + (x3, y3) / 0.1) / (1 / 0.2 + 1 / 0.1).

[0074] If the solution states contained in the second and third solution results are different, the position with the earlier solution state in the preset solution state order is determined as the post-processing positioning result of the rover. The preset solution state order, from front to back, can include, but is not limited to: fixed solution, floating-point solution, pseudorange difference decomposition, and single-point solution. For example, if the second solution result contains a fixed solution state and the third solution result contains a floating-point solution state, the fixed solution state is earlier in the preset solution state order; therefore, the second position is determined as the post-processing positioning result of the rover.

[0075] The method in this embodiment enhances the inverse filtering by using the solution result obtained from the first forward filtering for each epoch as input data during the second round of inverse filtering. This allows for deep fusion of ambiguities using the forward filtering result, thereby increasing the success rate of ambiguity fixation in this round of inverse filtering. Furthermore, after the second round of enhanced inverse filtering, a new round of forward filtering is added, using the solution result obtained from the second round of inverse filtering as input data. This enhanced inverse filtering result is then used to further fuse ambiguities, enhancing the forward filtering and increasing the success rate of ambiguity fixation in this round of forward filtering. This approach aims to fix ambiguities in as many epochs as possible, thereby improving the accuracy and reliability of PPK positioning.

[0076] Next, for Figure 5 The first solution operation shown Figure 6 The second solution operation shown Figure 7 The third solution operation shown will be described in detail.

[0077] Please see Figure 5 As shown, the first solution operation includes: single-point positioning operation, first quality control operation, first ambiguity update operation, first double-difference floating-point defiltering solution operation, first ambiguity fixing operation, first ambiguity fusion operation, and first positioning result output operation.

[0078] Single-point positioning mainly involves performing single-point positioning of the rover station based on observation data and ephemeris data to obtain the single-point positioning result. In this application, the post-processing positioning device can be implemented using any existing single-point positioning algorithm.

[0079] The first quality control operation is mainly used to identify and mark satellite signals with errors in the observations based on the characteristics of pseudorange observation data in the rover's observation data.

[0080] Among them, the rover observation data includes pseudorange observation data, which is the measured distance obtained by multiplying the propagation time of the ranging code signal transmitted by the satellite to the rover receiver antenna by the speed of light. It is a distance that is different from the real distance.

[0081] The characteristics of pseudorange observation data characterize the reliability of rover station observation data. These characteristics can include pseudorange residuals, baseband tracking information, and so on. By determining whether the rover station observation data meets the characteristics of pseudorange observation data, it is possible to identify whether there are errors in the satellite signal observations. Observations with errors need to be marked and removed to reduce the impact of erroneous observations on the accuracy of the solution.

[0082] The first ambiguity update operation mainly involves performing cycle slip detection, and then using different ambiguity update strategies based on different cycle slip detection results.

[0083] In GNSS technology, cycle slip refers to a jump or interruption in the integer cycle count caused by loss of satellite signal lock during carrier phase measurement. Cycle slip detection involves detecting whether cycle slips occur in carrier observations at epochs before and after the rover and base station.

[0084] In the event of a cycle slip, it is necessary to either repair the cycle slip or reset the ambiguity. Repairing a cycle slip involves estimating the integer cycle count of the lost satellite based on information from other satellites that have not lost lock. Resetting the ambiguity involves recalculating the initial ambiguity values ​​based on pseudorange observation data from both the rover and base station.

[0085] If no cycle slip occurs, the double difference ambiguity of the previous epoch can be maintained until the current epoch.

[0086] Based on this, the first ambiguity update operation can yield two results: one is to repair the ambiguity determined by the cycle slip / reset the ambiguity; the other is to recursively maintain the double-difference ambiguity.

[0087] The first double-difference floating-point solution filtering operation is mainly based on the short baseline double-difference observation equation, using the Kalman filter algorithm to estimate the first candidate position of the rover and estimate the floating-point double-difference ambiguity.

[0088] The equations for the double-difference pseudorange and carrier observation are shown in equation (1):

[0089] Formula (1) in, This represents the double-difference pseudorange observations from satellites i and j, rover station r, and base station b. This represents the double-difference carrier observations from satellites i and j, rover station r, and base station b. This represents the double-difference geometric distance from rover station r and base station b to satellites i and j; Indicates the carrier wavelength; Indicates double-difference ambiguity; This indicates the noise in the double-difference pseudorange measurement; This indicates double-difference carrier measurement noise.

[0090] The linearized expansion of the above formula (1) is expressed as the Kalman filter observation equation as shown in formula (2): Formula (2) Where Z represents the measured value, H represents the coefficient matrix of the observation equation, X represents the filter estimation parameters, which include the rover position and double-difference ambiguity, and v represents the measurement noise. In the first round of forward filtering, X contains the first candidate position of the rover and the floating-point double-difference ambiguity. Therefore, by using the above formula, the first candidate position of the rover and the floating-point double-difference ambiguity can be estimated using formula (2).

[0091] The first ambiguity fixing operation is mainly used to fix the floating-point double-difference ambiguity obtained from the first double-difference floating-point solution filtering operation, so as to improve the positioning solution accuracy. In this application, the ambiguity can be searched and fixed by the least-squares ambiguity deorrelation adjustment method (LAMBDA). The ambiguity fixed by the LAMBDA algorithm can be expressed as the following formula (3): Formula (3) in, Represents the ambiguity floating-point solution. This represents a solution with fixed ambiguity. The variance represents the degree of ambiguity. Represents an n-dimensional integer space. The floating-point solution of ambiguity substituted into formula (3) is the floating-point double-difference ambiguity obtained by the first double-difference floating-point solution filtering operation, and the fixed solution of ambiguity calculated by formula (3) is the searched fixed ambiguity.

[0092] It should be noted that the first ambiguity fixation operation can yield two results: one is that a fixed ambiguity is found; the other is that a fixed ambiguity is not found.

[0093] In some embodiments, after a fixed ambiguity is found, it can be verified to ensure that the fixed ambiguity is accurate and reliable. Verification can be performed, but is not limited to, using methods such as ratio value testing or hypothesis testing.

[0094] The first ambiguity fusion operation mainly involves fusing the results of the first ambiguity update operation and the first ambiguity fixing operation. Specifically, during the first round of forward filtering, the ambiguity data for one epoch comes from two sources: one part is the carrier corresponding to the fixed double-difference ambiguity of the previous epoch, which has been confirmed by cycle slip detection to have not experienced a cycle slip and can be recursively maintained in the current epoch; the other part is the ambiguity search and fixation obtained after filtering in the current epoch. If two parts of double-difference ambiguity exist, then the two parts are fused together.

[0095] The ambiguity unification and fusion can be achieved in the following ways: When identical reference satellites exist, fusion is performed based on those reference satellites. For example, the result of performing the first ambiguity update operation (the first part of the double-difference ambiguity set) is {N}. 12 N 13 N 14 The result of performing the first ambiguity fixing operation (the second part of the double-difference ambiguity set) is {N}. 15 N 16 N 17}, then the first fuzzy set obtained by fusion is {N} 12 N 13 N 14 N 15 N 16 N 17}, N ij This represents the double-difference ambiguity between satellite i and satellite j.

[0096] When no identical reference satellite exists, the result with the largest number of ambiguities is selected as the ambiguity unification and fusion result. For example, the result of performing the first ambiguity update operation (the first part of the double-difference ambiguity set) is {N}. 12 N 13 N 14 The result of performing the first ambiguity fixing operation (the second part of the double-difference ambiguity set) is {N}. 56 N 57}, then the first fuzzy set obtained by fusion is: {N 12 N 13 N 14}

[0097] The first positioning result output operation mainly involves further resolving the first candidate position based on the result of the first fuzziness fusion operation (i.e., the first fuzziness set), and then outputting and storing the first resolution result of the epoch.

[0098] Among them, the fixed solution is obtained based on the first ambiguity set and the first candidate position, and by the mixed integer least squares method, which can be expressed as the following formula (4): Formula (4) in, Represents the position parameter components, This represents a solution with fixed ambiguity. Represents the ambiguity floating-point solution. The covariance representing the position and ambiguity. The variance representing the ambiguity. This represents the variance of the location.

[0099] In this application, the first position of the first rover station can be obtained by substituting the first candidate position and the ambiguity in the first ambiguity set into formula (4). Furthermore, the solution error of the floating-point solution can be obtained after the first floating-point solution filtering operation, and the solution error of the fixed solution can be obtained by the second formula in formula (4).

[0100] The processing flow of the second solution operation is as follows: Figure 6 As shown, please refer to Figure 6 The second solution operation includes: single-point positioning operation, first auxiliary quality control operation, second ambiguity update operation, second double-difference floating-point solution filtering operation, second ambiguity fixing operation, first auxiliary ambiguity fusion operation, second ambiguity fusion operation, and second positioning result output operation.

[0101] The single-point positioning operation in the second solution operation is similar to the single-point positioning operation in the first solution operation, and will not be described again here.

[0102] The first auxiliary quality control operation mainly involves marking and removing observations with errors in the rover station's observation data based on the first position and the observation data of the current epoch in the first solution result.

[0103] In some embodiments, the post-processing positioning device uses the first position as the prior position of the current epoch, calculates the prior pseudorange residual using the prior position and the observation data of the current epoch, then determines the error threshold based on the prior pseudorange residual and the first position calculation error, and then marks and removes satellite signals with errors based on the error threshold.

[0104] Among them, the prior pseudorange residual is represented as the pseudorange residual obtained by subtracting the prior pseudorange calculated based on the first position from the pseudorange data in the current epoch observation data.

[0105] This application can calculate the error threshold based on the statistical value of the prior pseudorange residuals and the first position calculation error. For example: error threshold = R times the median of all prior pseudorange residuals + first position calculation error, for example, R = 3. The value of R can be set according to the requirements. This is just an example.

[0106] Compared with the first quality control operation, the first auxiliary quality control operation introduces the result of the forward filtering calculation as prior information, providing more data basis for the identification error observation, thereby improving the quality control effect.

[0107] The processing flow for the second ambiguity update operation is similar to that for the first ambiguity update operation, and can be referred to as follows: Figure 5 Detailed description of the embodiment. It should be noted that the difference between the second ambiguity update operation and the first ambiguity update operation lies in the fact that the previous epoch of the current epoch is different in the first and second directions, depending on the filtering solution direction. For example, for the k-th epoch, when performing the first ambiguity update operation, its previous epoch is the (k-1)-th epoch; when performing the second ambiguity update operation, its previous epoch is the (k+1)-th epoch.

[0108] The second double-difference floating-point solution filtering operation is similar to the first double-difference floating-point solution filtering operation, and the second ambiguity fixing operation is similar to the first ambiguity fixing operation. (Refer to...) Figure 5 The detailed description of the illustrated embodiments will not be repeated here.

[0109] The first auxiliary ambiguity fusion operation mainly involves calculating the auxiliary double-difference fixed ambiguity for each satellite at each frequency point in the current epoch when the solution state at the first position of the current epoch is a fixed solution, based on the first position of the rover station and the observation data of the current epoch. Then, depending on whether the auxiliary double-difference fusion is reliable, the first a priori fixed ambiguity of the current epoch is determined or it is determined that there is no first a priori fixed ambiguity in the current epoch.

[0110] The auxiliary double-difference floating-point ambiguity for each satellite at each frequency point in the current epoch can be calculated using the following formula (5): Formula (5) Indicates the auxiliary double-difference floating-point ambiguity. This represents the double-difference carrier observations from satellites i and j, rover station r, and base station b. This represents the double-difference geometric distances from rover station r and base station b to satellites i and j. Indicates the carrier wavelength; and It is calculated based on the observation data of the aforementioned epoch.

[0111] Due to measurement error and prior fixed solution error, the candidate double difference ambiguity calculated by formula (5) is not an integer. When the candidate double difference ambiguity is not an integer, the auxiliary double difference floating-point ambiguity calculated by formula (5) can be rounded to obtain the auxiliary double difference fixed ambiguity.

[0112] To determine whether the auxiliary double-difference fixed ambiguity is reliable, the rounded residual of the double-difference ambiguity for each satellite can be calculated. The rounded residual of the double-difference ambiguity can be expressed as the following formula (6): V Formula (6) Where V represents the rounded residual of the double-difference ambiguity. This indicates rounding down.

[0113] The rounded residual of the double-difference ambiguity represents the integer characteristic of the double-difference carrier ambiguity. Combined with the first position calculation error, it is used to determine whether the prior fixed solution position (i.e., the first position of the rover) of this epoch is reliable. In some embodiments, the determination condition for the integer characteristic is whether the residual statistical value of the rounded residual of the double-difference ambiguity meets a preset residual statistical threshold. For example, the determination condition for the integer characteristic is whether the mean residual of the rounded residual of the double-difference ambiguity is less than a preset mean residual of 0.1. If it is less, the prior fixed solution position obtained by the first round of forward filtering is determined to be reliable, and the candidate ambiguity is used as the first prior fixed ambiguity; otherwise, the prior fixed solution position obtained by the first round of forward filtering is determined to be unreliable, and it is determined that there is no first prior fixed ambiguity in the current epoch.

[0114] The second ambiguity fusion operation mainly fuses the results of the second ambiguity update operation, the second ambiguity fixing operation, and the first auxiliary ambiguity fusion operation. Specifically, during the second round of enhanced inverse filtering, the ambiguity data for one epoch comes from three sources: the first is the carrier corresponding to the fixed double-difference ambiguity of the previous epoch, which has been confirmed by cycle slip detection to have not experienced a cycle slip and can be recursively maintained in the current epoch; the second is the ambiguity search and fixation of the current epoch after filtering; and the third is the first prior fixed ambiguity determined based on the prior position of this epoch from the previous forward calculation and the observation data of the current epoch. If all three parts of double-difference ambiguity exist, they are fused uniformly. If at least two parts of double-difference ambiguity data exist, they are fused uniformly.

[0115] The ambiguity unification fusion method is similar to the aforementioned method. That is, when there are identical reference satellites, the fusion is performed based on the reference satellites. When there are no identical reference satellites, the ambiguity set with the largest number of ambiguities is selected, thereby unifying and fusing the three parts of ambiguity data into a second ambiguity set.

[0116] The second positioning result output operation mainly involves further resolving the second candidate position based on the result of the second ambiguity fusion operation (i.e., the second ambiguity set), and outputting and storing the second resolution result for each epoch. The resolution method can be found in [reference needed]. Figure 5 The detailed description of the embodiments is omitted here.

[0117] The processing flow of the third solution operation is as follows: Figure 7 As shown, please refer to Figure 7 The third solution operation includes: single-point positioning operation, second auxiliary quality control operation, third ambiguity update operation, third double-difference floating-point solution filtering operation, third ambiguity fixing operation, second auxiliary ambiguity fusion operation, third ambiguity fusion operation, and third positioning result output operation.

[0118] The single-point positioning operation in the third solution operation is similar to the single-point positioning operation in the second solution operation, and will not be described again here.

[0119] The second auxiliary quality control operation mainly involves marking and removing observations with errors in the base station observation data based on the second position and the observation data of the current epoch in the second solution result.

[0120] In some embodiments, the post-processing positioning device uses the second position as the prior position for the current epoch, calculates the prior pseudorange residual using the prior position and the observation data of the current epoch, then determines an error threshold based on the pseudorange residual and the second position calculation error, and finally marks and removes satellite signals with errors according to this error threshold. The specific implementation process is as follows... Figure 6 The first auxiliary quality control operation shown is similar, and for the sake of simplicity, it will not be described again here.

[0121] Compared with the first quality control operation, the second auxiliary quality control operation introduces the result of enhanced inverse filtering as prior information, providing more data basis for the identification error observation, thereby improving the quality control effect.

[0122] The processing flow for the third ambiguity update operation is similar to that for the first ambiguity update operation, and can be referred to as follows: Figure 5 Detailed description of the embodiment. It should be noted that when performing the second ambiguity update operation, the previous epoch of the current epoch is related to the direction of the filtering solution. For example, for the k-th epoch, when performing the first ambiguity update operation, its previous epoch is the (k-1)-th epoch; when performing the second ambiguity update operation, its previous epoch is the (k+1)-th epoch; and when performing the third ambiguity update operation, its previous epoch is the (k-1)-th epoch.

[0123] The third double-difference floating-point solution filtering operation is similar to the first double-difference floating-point solution filtering operation, and the third ambiguity fixing operation is similar to the first ambiguity fixing operation. (Refer to...) Figure 5 The detailed description of the illustrated embodiments will not be repeated here.

[0124] The second auxiliary ambiguity fusion operation mainly involves calculating candidate double-difference ambiguities for each satellite at each frequency point in the current epoch, based on the rover's second position and the observation data of the current epoch, when the solution state at the second position of the current epoch is a fixed solution. Then, depending on the reliability of the candidate double-difference ambiguities, it determines the second prior fixed ambiguity of the current epoch or determines that there is no second prior fixed ambiguity in the current epoch. The specific implementation method is the same as... Figure 6 The implementation of the first auxiliary ambiguity fusion operation shown is similar, and for the sake of simplicity, it will not be described in detail here.

[0125] The third ambiguity fusion operation mainly fuses the results of the third ambiguity update operation, the third ambiguity fixing operation, and the second auxiliary ambiguity fusion operation. That is, during the third round of enhanced inverse filtering, the ambiguity data for one epoch comes from three sources: the first part is the carrier corresponding to the fixed double-difference ambiguity of the previous epoch, which has been confirmed by cycle slip detection to have not experienced a cycle slip and can be recursively maintained in the current epoch; the second part is the ambiguity search and fixation of the current epoch after filtering; the third part is the second prior fixed ambiguity determined based on the prior position of this epoch from the previous forward solution and the observation data of the current epoch. If all three parts of double-difference ambiguity exist, they are fused uniformly. If only one or two parts of double-difference ambiguity data exist, they are fused uniformly.

[0126] The ambiguity unification fusion method is similar to the aforementioned method. That is, when there are identical reference satellites, the fusion is performed based on the reference satellites. When there are no identical reference satellites, the ambiguity set with the largest number of ambiguities is selected, thereby unifying and fusing the three parts of ambiguity data into a third ambiguity set.

[0127] The third positioning result output operation mainly involves further resolving the third candidate position based on the result of the third ambiguity fusion operation (i.e., the third ambiguity set), and outputting and storing the third resolution result for each epoch. The resolution method can be found in [reference needed]. Figure 5 The detailed description of the embodiments is omitted here.

[0128] In conclusion, Figures 5 to 7 The processing flow of the first, second, and third solution operations is illustrated in detail. Specifically, the fuzzy fusion operation in the second and third solution operations unifies and merges the fuzzy data from the three parts. Next, through... Figure 8 The illustrated embodiment describes the specific process of ambiguity unification and fusion.

[0129] See Figure 8As shown, the three dashed boxes 801, 802 and 803 from right to left represent the processing flow of obtaining a part of the fuzzy data by searching for fixed fuzziness, the processing flow of obtaining the second part of the fuzzy data by fuzzy recursion, and the processing flow of obtaining the third part of the fuzzy data by auxiliary fuzzy fusion, respectively.

[0130] Referring to the dashed box 801, obtaining a portion of the ambiguity data by searching for fixed ambiguity is mainly achieved by performing target double-difference floating-point solution filtering and target ambiguity fixing operations on the epoch observation data. Figure 8 If a fixed fuzziness is successfully found, then that part of the fuzziness data is called the searched fixed fuzziness; otherwise, it is considered that there is no searched fixed fuzziness.

[0131] Referring to the dashed box 802, the acquisition of the second part of ambiguity data through ambiguity recursion is mainly achieved by performing a target ambiguity update operation. Specifically, it is first determined whether the solution state of the previous epoch is a fixed solution. If so, cycle slip detection is further performed, and the results of the cycle slip detection and the preset ambiguity update strategy are processed to determine whether ambiguity recursion is successful. If successful, the second part of ambiguity data is successfully acquired, which can also be called the recursive fixed ambiguity; if it fails, it means that there is no second part of ambiguity data, that is, no recursive fixed ambiguity.

[0132] Referring to the dashed box 803, the acquisition of the third part of ambiguity data through auxiliary ambiguity fusion is mainly achieved through target auxiliary ambiguity fusion operation. The solution result of the previous round of calculation and the observation data of the current epoch are the input data for the target auxiliary ambiguity fusion operation. The solution result of the previous round of calculation can also be understood as prior data. Specifically, it is first determined whether the solution state contained in the prior data is a fixed solution; if it is not a fixed solution, it is determined that there is no prior fixed ambiguity; if it is a fixed solution, it is further determined whether the prior position calculation error is less than a preset error threshold; if it is greater, it is determined that there is no prior fixed ambiguity; if it is less, candidate prior fixed ambiguities are calculated according to the double-difference observation equation, and then the ambiguity integer consistency is determined. If the ambiguity integer consistency is satisfied, the third part of ambiguity data is successfully acquired based on the candidate prior fixed ambiguities, and this part of data can also be called prior fixed ambiguity; if the ambiguity integer consistency is not satisfied, it means that there is no third part of ambiguity data, i.e., no prior fixed ambiguity.

[0133] It should be noted that, Figure 8The dashed box 803 illustrates one possible implementation for determining the prior fixed ambiguity. In practical applications, the prior fixed ambiguity can also be determined in other ways. Please refer to the detailed description of the first auxiliary ambiguity fusion operation and the second auxiliary ambiguity fusion operation in the previous text. For the sake of brevity, it will not be repeated here.

[0134] Then, the search fixed fuzziness, the recursive fixed fuzziness, and the prior fixed fuzziness are fused according to the unified fusion method provided in this application.

[0135] It should be noted that there may be situations where one or more of the following cannot be obtained: search fixed fuzziness, recursive fixed fuzziness, and prior fixed fuzziness. If two parts of fuzzy data exist, they are fused according to the unified fusion method provided in this application. If only one part of the fuzzy data exists, that part of the fuzzy data is determined to be the result of the fusion.

[0136] It should also be noted that if the second solution operation is performed, the target double-difference floating-point filtering solution operation and the target ambiguity fixing operation shown in dashed box 801 are respectively the second double-difference floating-point filtering solution operation and the second ambiguity fixing operation; the target ambiguity update operation shown in dashed box 802 is the second ambiguity update operation; and the target auxiliary ambiguity fusion operation shown in dashed box 803 is the first auxiliary ambiguity fusion operation. If the third solution operation is performed, the target double-difference floating-point filtering solution operation and the target ambiguity fixing operation shown in dashed box 801 are respectively the third double-difference floating-point filtering solution operation and the third ambiguity fixing operation; the target ambiguity update operation shown in dashed box 802 is the third ambiguity update operation; and the target auxiliary ambiguity fusion operation shown in dashed box 803 is the second auxiliary ambiguity fusion operation.

[0137] In summary, the multi-directional fusion post-processing positioning method provided in this application enables as many epochs as possible to fix ambiguity, thereby improving the accuracy and reliability of PPK positioning.

[0138] Figure 9 This is a structural diagram of a multi-directional fusion post-processing positioning device provided in an embodiment of this application. Please refer to... Figure 9 As shown, the multi-directional fusion post-processing positioning device 900 of this embodiment includes: The data acquisition module 901 is used to acquire observation data for N epochs, where N is a positive integer greater than 1.

[0139] The data processing module 902 performs a first solution operation along a first direction for each epoch, based on the observation data of that epoch, to obtain a first solution result for that epoch. The first direction is the direction from the 1st epoch to the Nth epoch. The first solution result includes: the first position of the rover, the solution state of the first position, and the solution error of the first position. Part of the first solution operation consists of: a first ambiguity update operation, a first double-difference floating-point filtering solution operation, and a first ambiguity fixing operation. The first ambiguity update operation is used to maintain ambiguity recursively based on the double-difference ambiguity of the previous epoch in the first direction. The first double-difference floating-point filtering solution operation is used to estimate the first candidate position of the rover and the first floating-point double-difference ambiguity based on the observation data of that epoch. The first ambiguity fixing operation is used to fix the first floating-point double-difference ambiguity. The results of the first ambiguity update operation and the first ambiguity fixing operation are fused to obtain a first ambiguity set. The first position is obtained by updating the first candidate position based on the first ambiguity. Along the second direction, for each epoch, a second solution operation is performed based on the first solution result of the epoch and the observation data of the epoch to obtain the second solution result of the epoch; the second direction is the direction from the Nth epoch to the 1st epoch; the second solution result includes the second position of the rover, the solution state of the second position, and the solution error of the second position; some operations of the second solution operation are: a second ambiguity update operation, a second double-difference floating-point solution filtering calculation, a second ambiguity fixing operation, and a first auxiliary ambiguity fusion operation; the second ambiguity update operation is used to perform ambiguity recursion based on the double-difference ambiguity of the previous epoch in the second direction. The process is as follows: The second double-difference floating-point defiltering operation is used to estimate the second candidate position and the second floating-point double-difference ambiguity of the rover station based on the observation data of the epoch; the second ambiguity fixing operation is used to fix the second floating-point double-difference ambiguity; the first auxiliary ambiguity fusion operation is used to determine whether the epoch has a first prior fixed ambiguity based on the first solution result; ambiguity fusion is performed based on the result of the second ambiguity update operation, the result of the second ambiguity fixing operation, and the result of the first auxiliary ambiguity fusion operation to obtain a second ambiguity set, and the second position is updated based on the second ambiguity to obtain the second candidate position; Along the first direction, for each epoch, a third solution operation is performed based on the second solution result of the epoch and the observation data of the epoch to obtain the third solution result of the epoch; the third solution result includes the third position of the rover, the solution state of the third position, and the solution error of the third position; some operations of the third solution operation are: a third ambiguity update operation, a third double-difference floating-point solution filtering calculation, a third ambiguity fixing operation, and a second auxiliary ambiguity fusion operation; the third ambiguity update operation is used to maintain ambiguity recursively based on the double-difference ambiguity of the previous epoch in the first direction; the third double-difference floating-point... The defiltering operation is used to estimate the third candidate position and the third floating-point double-difference ambiguity of the rover station based on the observation data of the epoch; the third ambiguity fixing operation is used to fix the third floating-point double-difference ambiguity; the second auxiliary ambiguity fusion operation is used to determine whether there is a second prior fixed ambiguity in the epoch based on the second solution result; the ambiguity fusion of the result of the third ambiguity update operation, the result of the third ambiguity fixing operation, and the result of the second auxiliary ambiguity fusion operation is performed to obtain a third ambiguity set, and the third position is updated based on the third ambiguity to obtain the third candidate position; For each of the N epochs, the second solution result and the third solution result of the epoch are fused to obtain the post-processing positioning result of the rover in the epoch.

[0140] In some embodiments, the data processing module 902 is specifically configured to determine that the epoch does not have a target prior fixed ambiguity if the solution state included in the input solution result is a non-fixed solution; wherein, when performing the second solution operation for the epoch, the input solution result is the first solution result of the epoch, and the target prior fixed ambiguity is the first prior fixed ambiguity; when performing the third solution operation for the epoch, the input solution result is the second solution result of the epoch, and the target prior fixed ambiguity is the second prior fixed ambiguity; If the solution state included in the input solution result is a fixed solution, and the error in the rover location solution included in the input solution result is greater than a preset error threshold, then it is determined that there is no target prior fixed ambiguity in the epoch. If the solution state included in the input solution result is a fixed solution, and the rover position solution error included in the input solution result is less than or equal to the preset error threshold, then the auxiliary double-difference floating-point ambiguity of each satellite at each frequency point is calculated based on the rover position included in the input solution result and the observation data of the epoch. The auxiliary double-difference floating-point ambiguity of each satellite at each frequency point is rounded down to obtain the auxiliary double-difference fixed ambiguity of each satellite at each frequency point. Based on whether the auxiliary double-difference fixed ambiguity of each satellite at each frequency point satisfies the ambiguity integer consistency, it is determined whether the epoch has a target prior fixed ambiguity.

[0141] In some embodiments, the data processing module 902 is specifically used to obtain the auxiliary double-difference floating-point ambiguity of each satellite at each frequency point based on the rover location and the observation data of the epoch included in the target solution result, using a preset double-difference carrier observation equation.

[0142] The preset double-difference carrier observation equation is as follows: ; Indicates the auxiliary double-difference floating-point ambiguity. This represents the double-difference carrier observations from satellites i and j, rover station r, and base station b. This represents the double-difference geometric distances from rover station r and base station b to satellites i and j. Indicates the carrier wavelength; and It is calculated based on the observation data of the aforementioned epoch.

[0143] In some embodiments, the data processing module 902 is specifically used to calculate the double-difference ambiguity residual of each satellite at each frequency point for the auxiliary double-difference floating-point ambiguity and the auxiliary double-difference fixed ambiguity of each satellite at each frequency point; Calculate the residual statistics for all double-difference ambiguity residuals; If the residual statistics value is less than the preset residual statistics threshold, it is determined that the target prior fixed ambiguity exists in the epoch; wherein, the target prior fixed ambiguity of the epoch includes the auxiliary double difference fixed ambiguity of each satellite at each frequency point; If the residual statistics value is greater than or equal to the preset residual statistics threshold, then it is determined that the target prior fixed ambiguity does not exist in the epoch.

[0144] In some embodiments, the data processing module 902 is specifically used to fuse the results of at least two operations according to a preset fusion strategy when at least two of the second ambiguity update operation, the second ambiguity fixing operation, and the first auxiliary ambiguity fusion operation are successfully executed. The preset fusion strategy is as follows: if there is a common reference satellite, the results of the at least two operations are fused according to the common reference satellite; if there is no common reference satellite, the result with the largest number of ambiguities in the results of the at least two operations is determined as the second ambiguity. When one of the second fuzziness update operation, the second fuzziness fixation operation, and the first auxiliary fuzziness fusion operation is successfully executed, the result of the successfully executed operation is determined as the second fuzziness set.

[0145] In some embodiments, the target solution operation includes: an auxiliary quality control operation, which is performed before the ambiguity update operation; the target solution operation is either the second solution operation or the third solution operation; the data processing module 902 is specifically used to calculate the pseudorange residual based on the rover location and the observation data of the epoch included in the input solution result; wherein, when the target solution operation is the second solution operation, the input solution result is the first solution result of the epoch; when the target solution operation is the third solution operation, the input solution result is the second solution result of the epoch. Based on the pseudorange residual and the rover position calculation error included in the input calculation results, the error threshold of the observation value is determined; Based on the error threshold of the observed values, observation data that does not meet the error threshold in the observation data of the epoch are removed.

[0146] In some embodiments, the data processing module 902 is specifically used to fuse the second solution result and the third solution result in the following manner: If the second solution state of the epoch and the third solution state of the epoch are the same, then the second position and the third position are weighted and summed according to the second position solution error and the third position solution error to obtain the post-processing positioning result of the rover station; wherein, the weighting coefficient of the second position is related to the reciprocal of the second position solution error, and the weighting coefficient of the third position is related to the reciprocal of the third position solution error. If the second solution state of the epoch is different from the third solution state of the epoch, the position with the earlier solution state in the second position and the third position is determined as the post-processing positioning result of the rover station according to the preset solution state order; wherein, the preset solution state order from front to back is: fixed solution, floating-point solution, pseudorange difference decomposition, and single-point solution.

[0147] The apparatus provided in this embodiment is used to implement the method of any of the preceding embodiments. Its implementation principle and technical effects can be referred to in the detailed description of the preceding method embodiments. For the sake of brevity, it will not be repeated here.

[0148] Figure 10 This is a structural diagram of an electronic device provided according to an embodiment of this application. Please refer to [link / reference]. Figure 10 As shown, the electronic device 1000 provided in this embodiment includes: a memory 1001 and a processor 1002.

[0149] The memory 1001 can be a separate physical unit, connected to the processor 1002 via a bus 1003. Alternatively, the memory 1001 and processor 1002 can be integrated and implemented in hardware. The memory 1001 stores program instructions, which the processor 1002 calls to execute the methods described in any of the above method embodiments.

[0150] Optionally, when some or all of the methods in the above embodiments are implemented by software, the vehicle terminal 1000 may also include only the processor 1002. The memory 1001 for storing programs is located outside the vehicle terminal 1000, and the processor 1002 is connected to the memory via circuits / wires to read and execute the programs stored in the memory. The processor 1002 may be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and an NP. The processor 1002 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0151] The memory 1001 may include volatile memory, such as random-access memory (RAM); the memory may also include non-volatile memory, such as flash memory, hard disk drive (HDD) or solid-state drive (SSD); the memory may also include a combination of the above types of memory.

[0152] For example, this application provides an electronic device including: a memory and a processor; the memory is configured to store computer program instructions, and the processor is configured to execute the computer program instructions, such that the electronic device implements the method of any embodiment herein.

[0153] For example, this application provides a computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor of an electronic device such that the electronic device, when executed, implements the methods of any of the preceding embodiments.

[0154] For example, this application provides a computer program product that, when run on an electronic device, causes the electronic device to perform the methods of any of the preceding embodiments.

[0155] For example, this application provides a chip, an interface circuit, and a logic circuit. The interface circuit is used to receive signals from other chips outside the chip and transmit them to the logic circuit, or to send signals from the logic circuit to other chips outside the chip. The logic circuit is used to implement the methods of any of the preceding embodiments.

[0156] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0157] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-directional fusion post-processing localization method, characterized in that, include: Obtain observation data for N epochs; N is a positive integer greater than 1; Along the first direction, for each epoch, a first solution operation is performed based on the observation data of the epoch to obtain the first solution result of the epoch; The first direction is the direction from the 1st epoch to the Nth epoch; The first solution result includes: the first position of the rover, the solution state of the first position, and the solution error of the first position; some operations of the first solution operation are: a first ambiguity update operation, a first double-difference floating-point filtering solution operation, and a first ambiguity fixing operation; the first ambiguity update operation is used to maintain ambiguity recursively based on the double-difference ambiguity of the previous epoch in the first direction; the first double-difference floating-point filtering solution operation is used to estimate the first candidate position of the rover and the first floating-point double-difference ambiguity based on the observation data of the epoch; the first ambiguity fixing operation is used to fix the first floating-point double-difference ambiguity; the results of the first ambiguity update operation and the first ambiguity fixing operation are fused to obtain a first ambiguity set; the first position is updated based on the first ambiguity set to obtain the first candidate position; Along the second direction, for each epoch, a second solution operation is performed based on the first solution result of the epoch and the observation data of the epoch to obtain the second solution result of the epoch; the second direction is the direction from the Nth epoch to the 1st epoch; the second solution result includes the second position of the rover, the solution state of the second position, and the solution error of the second position; some operations of the second solution operation are: a second ambiguity update operation, a second double-difference floating-point solution filtering calculation, a second ambiguity fixing operation, and a first auxiliary ambiguity fusion operation; the second ambiguity update operation is used to perform ambiguity recursion based on the double-difference ambiguity of the previous epoch in the second direction. The process is as follows: The second double-difference floating-point filtering operation is used to estimate the second candidate position and the second floating-point double-difference ambiguity of the rover station based on the observation data of the epoch; the second ambiguity fixing operation is used to fix the second floating-point double-difference ambiguity; the first auxiliary ambiguity fusion operation is used to determine whether the epoch has a first prior fixed ambiguity based on the first solution result; the results of the second ambiguity update operation, the second ambiguity fixing operation, and the first auxiliary ambiguity fusion operation are ambiguity fused to obtain a second ambiguity set; the second position is updated based on the second ambiguity set to obtain the second candidate position; Along the first direction, for each epoch, a third solution operation is performed based on the second solution result of the epoch and the observation data of the epoch to obtain the third solution result of the epoch; the third solution result includes the third position of the rover, the solution state of the third position, and the solution error of the third position; some operations of the third solution operation are: a third ambiguity update operation, a third double-difference floating-point solution filtering solution, a third ambiguity fixing operation, and a second auxiliary ambiguity fusion operation; the third ambiguity update operation is used to maintain ambiguity recursively based on the double-difference ambiguity of the previous epoch in the first direction; the third double-difference floating-point solution... The filtering operation is used to estimate the third candidate position and the third floating-point double-difference ambiguity of the rover station based on the observation data of the epoch; the third ambiguity fixing operation is used to fix the third floating-point double-difference ambiguity; the second auxiliary ambiguity fusion operation is used to determine whether there is a second prior fixed ambiguity in the epoch based on the second solution result; the ambiguity fusion of the result of the third ambiguity update operation, the result of the third ambiguity fixing operation, and the result of the second auxiliary ambiguity fusion operation is performed to obtain a third ambiguity set; the third position is updated based on the third ambiguity set to obtain the third candidate position; For each of the N epochs, the second solution result and the third solution result of the epoch are fused to obtain the post-processing positioning result of the rover in the epoch. Among them, the determination of whether the epoch has a target prior fixed ambiguity based on the input solution result in the first auxiliary ambiguity fusion operation and the second auxiliary ambiguity fusion operation includes: If the solution state included in the input solution result is not a fixed solution, then it is determined that the target prior fixed ambiguity does not exist in the epoch. If the solution state included in the input solution result is a fixed solution, and the rover position solution error included in the input solution result is greater than or equal to a preset error threshold, then it is determined that the target prior fixed ambiguity does not exist in the epoch. If the solution state included in the input solution result is a fixed solution, and the rover position solution error included in the input solution result is less than the preset error threshold, then based on the rover position included in the input solution result and the observation data of the epoch, the auxiliary double-difference floating-point ambiguity of each satellite at each frequency point is obtained using the preset double-difference carrier observation equation. The auxiliary double-difference floating-point ambiguity of each satellite at each frequency point is rounded down to obtain the auxiliary double-difference fixed ambiguity of each satellite at each frequency point; For each satellite at each frequency point, calculate the double-difference ambiguity residual for each satellite at each frequency point, and calculate the residual statistics of all double-difference ambiguity residuals. If the residual statistics value is less than the preset residual statistics threshold, it is determined that the ambiguity integer consistency is satisfied, and it is determined that the target prior fixed ambiguity exists in the epoch. The target prior fixed ambiguity includes the auxiliary double difference fixed ambiguity of each satellite at each frequency point. If the residual statistics value is greater than or equal to the preset residual statistics threshold, it is determined that the ambiguity integer consistency is not satisfied, and it is determined that the target prior fixed ambiguity does not exist in the epoch. Specifically, when performing the second solution operation for the epoch, the input solution result is the first solution result of the epoch, and the target prior fixed ambiguity is the first prior fixed ambiguity; when performing the third solution operation for the epoch, the input solution result is the second solution result of the epoch, and the target prior fixed ambiguity is the second prior fixed ambiguity.

2. The method according to claim 1, characterized in that, The preset double-difference carrier observation equation is: ; Indicates the auxiliary double-difference floating-point ambiguity. This represents the double-difference carrier observations from satellites i and j, rover station r, and base station b. This represents the double-difference geometric distances from rover station r and base station b to satellites i and j. Indicates the carrier wavelength; and It is calculated based on the observation data of the aforementioned epoch.

3. The method according to claim 1, characterized in that, The results of the second ambiguity update operation, the second ambiguity fixing operation, and the first auxiliary ambiguity fusion operation are fused, including: When at least two of the second ambiguity update operation, the second ambiguity fixing operation, and the first auxiliary ambiguity fusion operation are successfully executed, the results of the at least two operations are fused according to a preset fusion strategy. The preset fusion strategy is as follows: if there is a common reference satellite, the results of the at least two operations are fused according to the reference satellite; if there is no common reference satellite, the result with the largest number of ambiguities in the results of the at least two operations is determined as the second ambiguity set. When one of the second fuzziness update operation, the second fuzziness fixation operation, and the first auxiliary fuzziness fusion operation is successfully executed, the result of the successfully executed operation is determined as the second fuzziness set.

4. The method according to claim 1, characterized in that, The target solution operation includes: an auxiliary quality control operation, which is performed before the ambiguity update operation; the target solution operation is either the second solution operation or the third solution operation; the execution of the target solution operation based on the input solution result of the epoch and the observation data of the epoch includes: Based on the rover location and the observation data of the epoch, which are included in the input solution results, the pseudorange residual is calculated; wherein, when the target solution operation is the second solution operation, the input solution result is the first solution result of the epoch; when the target solution operation is the third solution operation, the input solution result is the second solution result of the epoch. Based on the pseudorange residual and the accuracy of the rover position calculation included in the input calculation results, the error threshold of the observation value is determined; Based on the error threshold of the observed values, observation data that does not meet the error threshold in the observation data of the epoch are removed.

5. The method according to claim 1, characterized in that, The second and third solution results of the given epoch are fused to obtain the post-processed positioning result of the rover at the given epoch, including: If the second solution state of the epoch and the third solution state of the epoch are the same, then the second position and the third position are weighted and summed according to the second position solution error and the third position solution error to obtain the post-processing positioning result of the rover station; wherein, the weighting coefficient of the second position is related to the reciprocal of the second position solution error, and the weighting coefficient of the third position is related to the reciprocal of the third position solution error. If the second solution state of the epoch is different from the third solution state of the epoch, the position with the earlier solution state in the second position and the third position is determined as the post-processing positioning result of the rover station according to the preset solution state order; wherein, the preset solution state order from front to back is: fixed solution, floating-point solution, pseudorange difference decomposition, and single-point solution.

6. An electronic device, characterized in that, include: Memory and processor; The memory is configured to store computer program instructions; The processor is configured to run the computer program instructions, causing the electronic device to implement the multi-directional fusion post-processing positioning method as described in any one of claims 1 to 5.

7. A computer-readable storage medium, characterized in that, include: Computer program instructions; At least one processor of the electronic device executes the computer program instructions, causing the electronic device to implement the multi-directional fusion post-processing positioning method as described in any one of claims 1 to 5.

8. A chip, characterized in that, include: An interface circuit and a logic circuit, wherein the interface circuit is used to receive signals from other chips outside the chip and transmit them to the logic circuit, or to send signals from the logic circuit to other chips outside the chip, and the logic circuit is used to implement the multi-directional fusion post-processing positioning method as described in any one of claims 1 to 5.

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