Special satellite positioning test method and system for railway for observation-limited scene

Abstract

The invention discloses an observation-limited scene-oriented satellite positioning test method and system special for a railway. The method comprises the following steps of: establishing a limited track interval; obtaining a train IMU position and a first-level train GNSS position; judging whether the train passes through a limited track interval or not during test, and if the observation is limited, screening out an effective first-level train GNSS position based on the position residual error and constructing a second-level train GNSS position according to the effective first-level train GNSS position; calculating the final position of the train according to the IMU position of the train and the GNSS position of the secondary train; and completing track consistency according to the final position of the train and the position of the positioning tester. According to the method, the real-time computing power requirement is reduced in an off-line and on-line combined mode, the limited monitoring algorithm is designed to analyze the train surrounding observation limitation condition, the GNSS positioning signal optimization algorithm is designed to reduce abnormal signal interference, and the accuracy of the test method is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of positioning test, and in particular to a railway-specific satellite positioning test method and system for observation-restricted scenarios. Background Art

[0002] With the continuous development of public transportation technology, railway transportation has become an indispensable means of transportation in today's society due to its speed and convenience, and has played an irreplaceable role in cargo transportation, personnel exchanges, etc. In order to be able to grasp the movement trajectory of trains in a timely manner and ensure the safety and efficiency of railway train operation, railway satellite positioning technology has gradually become the focus of scientific researchers and front-line workers.

[0003] Most of the existing railway satellite positioning technologies rely on GNSS or Beidou signals to realize the positioning function of trains. Traditional satellite positioning test methods can realize basic positioning test functions, but during the operation of trains, they often pass through some scenes with limited observation. In these special scenes, satellite signals have problems of occlusion and multipath errors. Due to the high speed of trains, it is difficult to detect this problem in time, which leads to excessive positioning deviation and serious safety hazards. Therefore, it is necessary to propose a new railway-specific satellite positioning test method to solve the above problems. Summary of the invention

[0004] The present invention provides a railway-specific satellite positioning test method and system for observation-restricted scenarios, so as to solve the technical problems of difficulty in timely identifying observation-restricted scenarios, low real-time performance of positioning tests, and large deviations.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] The present invention provides a railway-specific satellite positioning test method for observation-restricted scenarios, comprising the following steps:

[0007] S1. Obtain the height values ​​of the train running track and the surrounding environment of the train running track, divide the train running track into zones, calculate the restriction of each track zone based on the height values ​​in the track zone, obtain the restricted track interval and upload it to the positioning tester;

[0008] S2. Obtain the train IMU position through the train IMU, obtain the first-level train GNSS position through the train GNSS receiver, and upload the train IMU position and the first-level train GNSS position to the positioning tester;

[0009] S3, initialize the positioning test time period, determine whether the train has passed through the observation restricted scene based on the current position of the train and the restricted trajectory section passed by the train during the positioning test time period, if the train has not passed through the observation restricted scene, calculate the final position of the train by the train IMU position and the first-level train GNSS position, and execute step S6 to perform trajectory consistency judgment, otherwise execute step S4 to optimize the GNSS signal;

[0010] S4, calculating the position residual between the train IMU position and the first-level train GNSS position during the positioning test period, screening out the valid first-level train GNSS position based on the position residual and constructing the second-level train GNSS position based on it;

[0011] S5, the final position of the train is calculated by the train IMU position and the secondary train GNSS position;

[0012] S6. Obtain the position of the positioning tester, and complete the trajectory consistency judgment based on the final position of the train and the position of the positioning tester during the positioning test period.

[0013] Furthermore, the step S1 comprises:

[0014] S11, obtaining the height value of the train running track and the surrounding environment of the train running track;

[0015] S12, dividing the track into zones:

[0016] The train track is partitioned according to the specifications of a meters * a meters, where a is greater than the width of the train. Each track partition takes the train track it contains as the central axis. For the track part that does not meet the specifications of a meters * a meters, it is calculated as a complete track partition to obtain the track partition G:

[0017] G={G 1 ,...,G i ,...,G n}

[0018] Where: G 1 represents the first trajectory partition, G i represents the i-th trajectory partition, G n represents the nth trajectory partition, n represents the number of trajectory partitions;

[0019] S13, dividing the trajectory into sub-partitions:

[0020] Each track partition is further divided into 9 track sub-partitions of the same size according to the specification of 3*3. The track sub-partitions are numbered 1-9 in the order of first along the width direction of the train and then along the length direction of the train. The expression of the i-th track partition is as follows:

[0021]

[0022] in, Indicates the maximum height value of the first track sub-partition in the i-th track partition. represents the maximum height value of the jth track sub-partition within the i-th track partition, represents the maximum height value of the 9th track sub-partition in the ith track partition;

[0023] The 1st, 4th, and 7th track subpartitions are considered as the first side, the 2nd, 5th, and 8th track subpartitions are considered as the second side, and the 3rd, 6th, and 9th track subpartitions are considered as the third side;

[0024] S14. Calculate the height of the trajectory sub-partition:

[0025] Calculate the trajectory partition G i Average height of the first side Average height of the second side and the average height of the third side The expression is as follows:

[0026]

[0027] S15, first side and third side restriction judgment:

[0028] Initialize height threshold Compare and The size of the value is based on the larger value and the height threshold The size relationship of determines the restriction of the first and third sides, and the expression is as follows:

[0029]

[0030] in, represents the restriction degree of the first side and the third side in the i-th trajectory partition;

[0031] when When , it means that the GNSS observations in the trajectory sub-area on the first side or the third side are limited. When , it means that GNSS observations in the trajectory sub-area on the first side or the third side are not restricted;

[0032] S16, second side restriction judgment:

[0033] Initialize height difference threshold Compute the difference in the average height of the second side between adjacent track partitions:

[0034] ΔG={ΔG 1 ,...,ΔG i,...,ΔG n-1}

[0035]

[0036] Based on the obtained difference and the height difference threshold The relationship between the size of the second side is used to determine the restriction of the second side. The expression is as follows:

[0037]

[0038] in, represents the restriction degree of the second side in the i-th trajectory partition;

[0039] when When , it means that the GNSS observations in the trajectory sub-area on the second side are limited. When , it means that the GNSS observations in the trajectory sub-area on the second side are not restricted;

[0040] S17, Constrained Integration Calculation:

[0041] Calculate the restriction degree of the i-th trajectory partition The expression is as follows:

[0042]

[0043] when When it is equal to 1 or 2, it means that the GNSS observation is limited in the i-th trajectory partition, and there is an observation-limited scenario. When it is equal to 0, it means that GNSS observation is not restricted in the i-th trajectory partition, and there is no observation restricted scenario;

[0044] S18, restricted trajectory interval:

[0045] By calculating the restriction degree of each trajectory partition, the restriction trajectory interval T is obtained 1,2,3 :

[0046]

[0047] in, They represent the degree of restriction of different trajectory partitions respectively;

[0048] S19, the restricted trajectory interval F 1,2,3 Will be uploaded to the positioning tester.

[0049] It should be noted that the train running track refers to the fixed running track of the train and is obtained by offline acquisition. During the positioning test, the train runs along this track, so the observation restrictions around the train running track can be analyzed in advance; the height value of the surrounding environment of the train running track is obtained through satellite maps, and the satellite maps can use existing digital maps, such as Amap, Baidu Map, etc. The use of satellite maps can reduce the workload and complexity of preliminary preparation work.

[0050] The track partition is divided into a first side, a second side and a third side, wherein the first side and the third side are used to determine whether there are tall objects in the surrounding environment of the train track, and the second side is located near the center of the track and is used to determine whether the train track passes through a tunnel; the value of a can be selected based on train parameters and actual test requirements.

[0051] The entire calculation process of the restriction and the restricted trajectory interval is completed offline before the positioning test, which can reduce the amount of online calculations during the positioning test and improve the real-time performance of the positioning test. By using the existing running track of the train and the existing satellite map, the real-time performance and accuracy of the observation of restricted scenes can be improved by combining multi-source information. The offline and online mentioned in the present invention refer to before the positioning test and during the positioning test, respectively.

[0052] Furthermore, the step S2 comprises:

[0053] S21. Get the train IMU position:

[0054] The train IMU is located in the middle of the train, and the train IMU position P is calculated by the train IMU signal. IMU :

[0055]

[0056] Among them, m represents the number of train IMU signals during the positioning test period, Indicates the train IMU position corresponding to the i-th train IMU signal;

[0057] S22. Obtain the GNSS position of the first-level train:

[0058] The two GNSS receivers are located at the head and tail of the train respectively. The positions of the two GNSS receivers are obtained by receiving GNSS signals:

[0059]

[0060] Among them, J 1 represents the GNSS receiver at the head of the train, J 2 represents the GNSS receiver at the rear of the train, u represents the number of GNSS signals received by the GNSS receiver during the positioning test period, Indicates J 1 The position when receiving the i-th GNSS signal, Indicates J 2 The position when receiving the i-th GNSS signal;

[0061] Depend on and Calculate the GNSS position of the first-level train

[0062]

[0063] in, represents the train position corresponding to the i-th GNSS signal;

[0064] S23, upload the train IMU position and the first-level train GNSS position to the positioning tester.

[0065] It should be noted that the train IMU is located in the middle of the train and in the middle of the two GNSS receivers, and the height of the train IMU and the two receivers are consistent. The position of the train IMU is calculated by integrating the linear acceleration and angular acceleration.

[0066] By combining the GNSS signals from two receivers for calculation, the error caused by a single receiver failure can be reduced, thereby avoiding systematic errors in the calculation process and improving the accuracy of the test method.

[0067] Furthermore, the step S3 comprises:

[0068] S31. Determine the restricted track section that the train passes through:

[0069] Initialize the positioning test time period T, obtain the average speed v of the train, and calculate the length of the test track interval:

[0070] L=λ*T*v

[0071] Where λ represents the length coefficient;

[0072] Calculate the number of trajectory partitions:

[0073] n=L / a

[0074] Based on the current position of the train and the number of track partitions, determine the restricted track section that the train passes through during the positioning test period

[0075] S32: Determine whether the train passes through an observation restricted scene based on the restricted trajectory interval:

[0076] When all the values ​​of the restrictions in the restricted trajectory interval are zero, it means that during the positioning test period, the scenes passed by the train are all unrestricted scenes. The final position of the train is calculated by the first-level train GNSS position and the train IMU position, and step S6 is executed to determine the trajectory consistency.

[0077] When there is a non-zero value of the restriction in the restricted trajectory interval, it means that during the positioning test period, there is an observation restricted scene in the scene where the train passes, and step S4 is executed to optimize the GNSS signal.

[0078] It should be noted that the average speed v of the train refers to the average speed of the last time the train ran along the same track; by combining the historical data of train operation and offline information, it is possible to quickly determine whether there is an observation-restricted scenario.

[0079] The length coefficient λ is set to avoid the restricted trajectory interval being too small due to the train speed being higher than the average speed during the positioning test phase. It is an empirical value and can also take a value in the range of [1,1.5]. The selection of this coefficient depends on the test conditions. If the restricted trajectory interval of the last test is smaller than the actual operating trajectory, the coefficient is increased. If the restricted trajectory interval of the last test is greater than or equal to the actual operating trajectory, the coefficient remains unchanged.

[0080] Furthermore, the step S4 comprises:

[0081] S41. Calculate the position residual between the train IMU position and the first-level train GNSS position:

[0082] At each moment, the train IMU collects a train IMU signal and the GNSS receiver receives a GNSS signal;

[0083] Get the train IMU position for t consecutive moments in the current positioning test period:

[0084]

[0085] Where t is an integer and is less than T;

[0086] Get the GNSS position of the first-level train for t consecutive moments in the current positioning test period:

[0087]

[0088] Due to the existence of observation-restricted scenarios, the train position calculated by the GNSS signal has deviations. Therefore, the set of position residuals ΔP between the train IMU position and the first-level train GNSS position at t consecutive moments in the current positioning test period is calculated, where the position residual ΔP at the i-th moment is i The expression is as follows:

[0089]

[0090] S42. Optimize the GNSS position of first-class trains:

[0091] Based on the position residual, calculate the probability Pr that the GNSS position of the i-th first-level train is a valid GNSS signal i , the expression is as follows:

[0092] Pr i =[(ΔP) max -ΔP i ] / [(ΔP) max -(ΔP) min ]

[0093] Where (ΔP) max represents the maximum value in ΔP, (ΔP) min represents the minimum value in ΔP;

[0094] Initialize the probability threshold α, and mark the GNSS position of the first-level train based on the relationship between the obtained probability and the probability threshold:

[0095] When Pr i ≥α, the GNSS position of the i-th first-level train is marked as a valid GNSS signal. i <α, the GNSS position of the i-th first-level train is marked as an invalid GNSS signal;

[0096] S43. Reconstruct the secondary train GNSS position using all valid GNSS signals.

[0097] Furthermore, the step S5 comprises:

[0098] Initialize adjustment coefficients β and γ, where β+γ=1;

[0099] The final position of the train is calculated by the train IMU position and the secondary train GNSS position, where the final position of the i-th train is The expression is as follows:

[0100]

[0101] in, represents the GNSS position of the i-th secondary train.

[0102] It should be noted that the fusion of the train IMU position and the secondary train GNSS position is achieved by selecting a suitable adjustment coefficient to ensure that the final position of the train, i.e., the train positioning test trajectory, is accurate and reliable.

[0103] Furthermore, the step S6 comprises:

[0104] S61, obtain the position P of the positioning tester C :

[0105]

[0106] Where w represents the number of secondary train GNSS positions;

[0107] S62, trajectory consistency judgment:

[0108] During the positioning test period, the cumulative error e between the final position of the train and the position of the positioning tester is calculated, and the expression is as follows:

[0109]

[0110] Initialize the cumulative error threshold ε, and output the trajectory consistency judgment result based on the relationship between the obtained cumulative error and the cumulative error threshold:

[0111] When e≥ε, it means that the train positioning test trajectory is consistent with the actual train trajectory, and the satellite positioning is accurate. When e<ε, it means that the train positioning test trajectory is inconsistent with the actual train trajectory, and the satellite positioning is inaccurate.

[0112] It should be noted that when conducting satellite positioning tests, a benchmark, that is, an accurate standard value, is required for comparison and judgment. The location of the positioning tester here can play the above role; the positioning tester is located in the middle of the train, and it calculates the exact position of the train based on known data such as the initial position of the train, the speed of the train, and the acceleration of the train. The collection of these positions is the actual trajectory of the train. The accurate position information can be used to determine whether the GNSS signal positioning is accurate.

[0113] The present invention also provides a railway-specific satellite positioning test system for observation-restricted scenarios, comprising the following modules:

[0114] Offline data processing module: obtain the height values ​​of the train running track and the surrounding environment of the train running track, divide the train running track into zones, calculate the restriction of each track zone based on the height values ​​in the track zone, obtain the restricted track interval and upload it to the positioning tester;

[0115] Real-time data acquisition module: obtain the train IMU position through the train IMU, obtain the first-level train GNSS position through the train GNSS receiver, and upload the train IMU position and the first-level train GNSS position to the positioning tester;

[0116] Restricted scene judgment module: Initialize the positioning test time period, and judge whether the train has passed through the observation restricted scene based on the current position of the train and the restricted trajectory section passed by the train during the positioning test time period. If the train has not passed through the observation restricted scene, run the trajectory consistency judgment module, otherwise run the GNSS signal optimization module;

[0117] GNSS signal screening module: calculates the position residual between the train IMU position and the first-level train GNSS position during the positioning test period, screens out the valid first-level train GNSS position based on the position residual and constructs the second-level train GNSS position based on it;

[0118] Trajectory consistency judgment module: The final position of the train is calculated by the train IMU position and the first-level train GNSS position, or the final position of the train is calculated by the train IMU position and the second-level train GNSS position, the position of the positioning tester is obtained, and the trajectory consistency judgment is completed by the final position of the train and the position of the positioning tester during the positioning test time period.

[0119] The beneficial effects brought about by the technical solution provided by the present invention include at least:

[0120] 1. The present invention adopts a combination of offline and online methods to realize the railway-specific satellite positioning test function for observation-restricted scenarios. After determining the running track of the railway train, a limitation monitoring algorithm is designed, and the limitation is calculated through the train running track and the satellite map, and then the restricted track interval is established offline. When it is found that the train passes through the restricted track interval during the positioning test time period, a GNSS signal optimization algorithm based on position residual is further designed, and the track consistency judgment is completed based on the final position of the train obtained after screening. Compared with the traditional full-time online testing method, the technical solution of the present invention reduces the computing power loss of online resources, has stronger real-time performance, can improve test efficiency, and is conducive to timely discovering that the train passes through the observation-restricted scene, thereby improving the accuracy of the test.

[0121] 2. The present invention designs a limitation monitoring algorithm to monitor the running track of the train. The train running track is first partitioned, and then each track partition is divided into track sub-partitions arranged in a nine-square grid and divided into a first side, a second side and a third side. The height values ​​of the first side and the third side are used to determine whether there are tall objects near the train track. The height value of the second side is used to determine whether the train track passes through a tunnel, and then the limitation is calculated to obtain a limited track interval. The present invention can more accurately analyze the observation limitation of the scene around the track by dividing the track into sub-areas, thereby improving the accuracy of the test method.

[0122] 3. Aiming at the situation where the train passes through the observation restricted scene, the present invention designs a GNSS signal optimization algorithm based on the residual between the train IMU position and the first-level train GNSS position, calculates the effective probability of each first-level train GNSS position by the position residual, reconstructs the second-level train GNSS position by the effective first-level train GNSS position, and integrates the second-level train GNSS position and the train IMU position to obtain the final position of the train for trajectory consistency judgment. The present invention can eliminate the interference caused by receiving abnormal GNSS signals in the observation restricted scene, and introduces the IMU position information for screening to improve the richness of sensor information and further improve the accuracy of the test method. BRIEF DESCRIPTION OF THE DRAWINGS

[0123] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0124] Figure 1 A flowchart of a railway-specific satellite positioning test method for observation-restricted scenarios provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0125] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0126] Example 1

[0127] This embodiment will be combined with the corresponding drawings to describe the method of the present invention in more detail. Figure 1 As shown, a railway-specific satellite positioning test method for observation-restricted scenarios includes:

[0128] S1. Obtain the height values ​​of the train running track and the surrounding environment of the train running track, divide the train running track into zones, calculate the restriction of each track zone based on the height values ​​in the track zone, obtain the restricted track interval and upload it to the positioning tester;

[0129] S2. Obtain the train IMU position through the train IMU, obtain the first-level train GNSS position through the train GNSS receiver, and upload the train IMU position and the first-level train GNSS position to the positioning tester;

[0130] S3, initialize the positioning test time period, determine whether the train has passed through the observation restricted scene based on the current position of the train and the restricted trajectory section passed by the train during the positioning test time period, if the train has not passed through the observation restricted scene, calculate the final position of the train by the train IMU position and the first-level train GNSS position, and execute step S6 to perform trajectory consistency judgment, otherwise execute step S4 to optimize the GNSS signal;

[0131] S4, calculating the position residual between the train IMU position and the first-level train GNSS position during the positioning test period, screening out the valid first-level train GNSS position based on the position residual and constructing the second-level train GNSS position based on it;

[0132] S5, the final position of the train is calculated by the train IMU position and the secondary train GNSS position;

[0133] S6. Obtain the position of the positioning tester, and complete the trajectory consistency judgment based on the final position of the train and the position of the positioning tester during the positioning test period.

[0134] Specifically,

[0135] The step S1 comprises:

[0136] S11, obtaining the height value of the train running track and the surrounding environment of the train running track;

[0137] S12, dividing the track into zones:

[0138] The train track is partitioned according to the specification of 15m*15m, where a is greater than the train width. Each track partition takes the train track it contains as the central axis. For the track part that does not meet the specification of 15m*15m, it is calculated as a complete track partition to obtain the track partition G:

[0139] G={G 1 ,...,G i ,...,G n}

[0140] Where: G 1 represents the first trajectory partition, G i represents the i-th trajectory partition, G n represents the nth trajectory partition, n represents the number of trajectory partitions;

[0141] S13, dividing the trajectory into sub-partitions:

[0142] Each track partition is further divided into 9 track sub-partitions of the same size according to the specifications of 3*3 (i.e. 5 meters * 5 meters). The track sub-partitions are numbered 1-9 in the order of first along the width direction of the train and then along the length direction of the train. The expression of the i-th track partition is as follows:

[0143]

[0144] in, Indicates the maximum height value of the first track sub-partition in the i-th track partition. represents the maximum height value of the jth track sub-partition within the i-th track partition, represents the maximum height value of the 9th track sub-partition in the ith track partition;

[0145] The 1st, 4th, and 7th track subpartitions are considered as the first side, the 2nd, 5th, and 8th track subpartitions are considered as the second side, and the 3rd, 6th, and 9th track subpartitions are considered as the third side;

[0146] S14. Calculate the height of the trajectory sub-partition:

[0147] Calculate the trajectory partition G i Average height of the first side Average height of the second side and the average height of the third side The expression is as follows:

[0148]

[0149] S15, first side and third side restriction judgment:

[0150] Initialize height threshold Compare and The size of the value is based on the larger value and the height threshold The size relationship of determines the restriction of the first and third sides, and the expression is as follows:

[0151]

[0152] in, represents the restriction degree of the first side and the third side in the i-th trajectory partition;

[0153] when When , it means that the GNSS observations in the trajectory sub-area on the first side or the third side are limited. When , it means that GNSS observations in the trajectory sub-area on the first side or the third side are not restricted;

[0154] S16, second side restriction judgment:

[0155] Initialize height difference threshold Compute the difference in the average height of the second side between adjacent track partitions:

[0156] ΔG={ΔG 1 ,...,ΔG i ,...,ΔG n-1}

[0157]

[0158] Based on the obtained difference and the height difference threshold The relationship between the size of the second side is used to determine the restriction of the second side. The expression is as follows:

[0159]

[0160] in, represents the restriction degree of the second side in the i-th trajectory partition;

[0161] when When , it means that the GNSS observations in the trajectory sub-area on the second side are limited. When , it means that the GNSS observations in the trajectory sub-area on the second side are not restricted;

[0162] S17, Constrained Integration Calculation:

[0163] Calculate the restriction degree of the i-th trajectory partition The expression is as follows:

[0164]

[0165] when When it is equal to 1 or 2, it means that the GNSS observation is limited in the i-th trajectory partition, and there is an observation-limited scenario. When it is equal to 0, it means that GNSS observation is not restricted in the i-th trajectory partition, and there is no observation restricted scenario;

[0166] S18, restricted trajectory interval:

[0167] By calculating the restriction degree of each trajectory partition, the restricted trajectory interval F is obtained 1,2,3 :

[0168]

[0169] in, They represent the degree of restriction of different trajectory partitions respectively;

[0170] S19, the restricted trajectory interval F 1,2,3 Will be uploaded to the positioning tester.

[0171] The step S2 comprises:

[0172] S21. Get the train IMU position:

[0173] The train IMU is located in the middle of the train, and the train IMU position P is calculated by the train IMU signal. IMU :

[0174]

[0175] Among them, m represents the number of train IMU signals during the positioning test period, Indicates the train IMU position corresponding to the i-th train IMU signal;

[0176] S22. Obtain the GNSS position of the first-level train:

[0177] The two GNSS receivers are located at the head and tail of the train respectively. The positions of the two GNSS receivers are obtained by receiving GNSS signals:

[0178]

[0179] Among them, J 1 represents the GNSS receiver at the head of the train, J 2 represents the GNSS receiver at the rear of the train, u represents the number of GNSS signals received by the GNSS receiver during the positioning test period, Indicates J 1 The position when receiving the i-th GNSS signal, Indicates J 2 The position when receiving the i-th GNSS signal;

[0180] Depend on and Calculate the GNSS position of the first-level train

[0181]

[0182] in, represents the train position corresponding to the i-th GNSS signal;

[0183] S23, upload the train IMU position and the first-level train GNSS position to the positioning tester.

[0184] The step S3 comprises:

[0185] S31. Determine the restricted track section that the train passes through:

[0186] Initialize the positioning test time period T, obtain the average speed v of the train, and calculate the length of the test track interval:

[0187] L=1.15*T*v

[0188] Calculate the number of trajectory partitions:

[0189] n=L / 15

[0190] Based on the current position of the train and the number of track partitions, determine the restricted track section that the train passes through during the positioning test period

[0191] S32: Determine whether the train passes through an observation restricted scene based on the restricted trajectory interval:

[0192] If all the values ​​of the restricted degrees in the restricted trajectory interval are zero, it means that during the positioning test period, the scenes passed by the train are all unrestricted scenes. The final position of the train is calculated by the first-level train GNSS position and the train IMU position, and step S6 is executed to determine the trajectory consistency.

[0193] If there is a non-zero value of the restriction in the restricted trajectory interval, it means that during the positioning test period, there is an observation restricted scene in the scene where the train passes, and step S4 is executed to optimize the GNSS signal.

[0194] Furthermore, the step S4 comprises:

[0195] S41. Calculate the position residual between the train IMU position and the first-level train GNSS position:

[0196] At each moment, the train IMU collects a train IMU signal and the GNSS receiver receives a GNSS signal;

[0197] Get the train IMU position for t consecutive moments in the current positioning test period:

[0198]

[0199] Where t is an integer and is less than T;

[0200] Get the GNSS position of the first-level train for t consecutive moments in the current positioning test period:

[0201]

[0202] Due to the existence of observation-restricted scenarios, the train position calculated by the GNSS signal has deviations. Therefore, the set of position residuals ΔP between the train IMU position and the first-level train GNSS position at t consecutive moments in the current positioning test period is calculated, where the position residual ΔP at the i-th moment isi The expression is as follows:

[0203]

[0204] S42. Optimize the GNSS position of first-class trains:

[0205] Based on the position residual, calculate the probability Pr that the GNSS position of the i-th first-level train is a valid GNSS signal i , the expression is as follows:

[0206] Pr i =[(ΔP) max -ΔP i ] / |[(ΔP) max -(ΔP) min ]

[0207] Where (ΔP) max represents the maximum value in ΔP, (ΔP) min represents the minimum value in ΔP;

[0208] Initialize the probability threshold α, and mark the GNSS position of the first-level train based on the relationship between the obtained probability and the probability threshold:

[0209] When Pr i ≥α, the GNSS position of the i-th first-level train is marked as a valid GNSS signal. i <α, the GNSS position of the i-th first-level train is marked as an invalid GNSS signal;

[0210] S43. Reconstruct the secondary train GNSS position using all valid GNSS signals.

[0211] Furthermore, the step S5 comprises:

[0212] Initialize adjustment coefficients β and γ, where β+γ=1;

[0213] The final position of the train is calculated by the train IMU position and the secondary train GNSS position, where the final position of the i-th train is The expression is as follows:

[0214]

[0215] in, represents the GNSS position of the i-th secondary train.

[0216] Furthermore, the step S6 comprises:

[0217] S61, obtain the position P of the positioning tester C :

[0218]

[0219] Where w represents the number of secondary train GNSS positions;

[0220] S62, trajectory consistency judgment:

[0221] During the positioning test period, the cumulative error e between the final position of the train and the position of the positioning tester is calculated, and the expression is as follows:

[0222]

[0223] Initialize the cumulative error threshold ε, and output the trajectory consistency judgment result based on the relationship between the obtained cumulative error and the cumulative error threshold:

[0224] When e≥ε, it means that the train positioning test trajectory is consistent with the actual train trajectory, and the satellite positioning is accurate. When e<ε, it means that the train positioning test trajectory is inconsistent with the actual train trajectory, and the satellite positioning is inaccurate.

[0225] Example 2

[0226] This embodiment provides a railway-specific satellite positioning test system for observation-restricted scenarios, including the following modules:

[0227] Offline data processing module: obtain the height values ​​of the train running track and the surrounding environment of the train running track, divide the train running track into zones, calculate the restriction of each track zone based on the height values ​​in the track zone, obtain the restricted track interval and upload it to the positioning tester;

[0228] Real-time data acquisition module: obtain the train IMU position through the train IMU, obtain the first-level train GNSS position through the train GNSS receiver, and upload the train IMU position and the first-level train GNSS position to the positioning tester;

[0229] Restricted scene judgment module: Initialize the positioning test time period, and judge whether the train has passed through the observation restricted scene based on the current position of the train and the restricted trajectory section passed by the train during the positioning test time period. If the train has not passed through the observation restricted scene, run the trajectory consistency judgment module, otherwise run the GNSS signal optimization module;

[0230] GNSS signal screening module: calculates the position residual between the train IMU position and the first-level train GNSS position during the positioning test period, screens out the valid first-level train GNSS position based on the position residual and constructs the second-level train GNSS position based on it;

[0231] Trajectory consistency judgment module: The final position of the train is calculated by the train IMU position and the first-level train GNSS position, or the final position of the train is calculated by the train IMU position and the second-level train GNSS position, the position of the positioning tester is obtained, and the trajectory consistency judgment is completed by the final position of the train and the position of the positioning tester during the positioning test time period.

[0232] This solution is applicable to both simulated and real scenarios.

[0233] The satellite positioning test system provided in this embodiment is used to implement the satellite positioning test method in the above-mentioned embodiment 1, wherein the functions implemented by each functional module of the satellite positioning test system correspond one-to-one to each step of the satellite positioning test method; therefore, they will not be repeated here.

[0234] It should be noted that the serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments. And the terms "including", "comprising" or any other variants thereof in this article are intended to cover non-exclusive inclusion, so that a process, device, article or method including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, device, article or method. In the absence of further restrictions, an element defined by the sentence "including a ..." does not exclude the presence of other identical elements in the process, device, article or method including the element.

[0235] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present invention.

[0236] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A railway-specific satellite positioning test method for observation-restricted scenarios, characterized in that: The following steps are involved: S1. Obtain the height values ​​of the train running track and the surrounding environment of the train running track, divide the train running track into zones, calculate the restriction of each track zone based on the height values ​​in the track zone, obtain the restricted track interval and upload it to the positioning tester; S2. Obtain the train IMU position through the train IMU, obtain the first-level train GNSS position through the train GNSS receiver, and upload the train IMU position and the first-level train GNSS position to the positioning tester; S3, initialize the positioning test time period, determine whether the train has passed through the observation restricted scene based on the current position of the train and the restricted trajectory section passed by the train during the positioning test time period, if the train has not passed through the observation restricted scene, calculate the final position of the train by the train IMU position and the first-level train GNSS position, and execute step S6 to perform trajectory consistency judgment, otherwise execute step S4 to optimize the GNSS signal; S4, calculating the position residual between the train IMU position and the first-level train GNSS position during the positioning test period, screening out the valid first-level train GNSS position based on the position residual and constructing the second-level train GNSS position based on it; S5, the final position of the train is calculated by the train IMU position and the secondary train GNSS position; S6. Obtain the position of the positioning tester, and complete the trajectory consistency judgment based on the final position of the train and the position of the positioning tester during the positioning test period.

2. The railway-specific satellite positioning test method for observation-restricted scenarios according to claim 1 is characterized in that: The step S1 comprises: S11, obtaining the height value of the train running track and the surrounding environment of the train running track; S12, dividing the track into zones: The train track is partitioned according to the specifications of a meters * a meters, where a is greater than the width of the train. Each track partition takes the train track it contains as the central axis. For the track part that does not meet the specifications of a meters * a meters, it is calculated as a complete track partition to obtain the track partition G: G={G1,...,G i ,...,G n } Where: G1 represents the first trajectory partition, G i represents the i-th trajectory partition, G n represents the nth trajectory partition, where n represents the number of trajectory partitions; S13, dividing the trajectory into sub-partitions: Each track partition is further divided into 9 track sub-partitions of the same size according to the specification of 3*3. The track sub-partitions are numbered 1-9 in the order of first along the width direction of the train and then along the length direction of the train. The expression of the i-th track partition is as follows: in, Indicates the maximum height value of the first track sub-partition in the i-th track partition. represents the maximum height value of the jth track sub-partition within the i-th track partition, represents the maximum height value of the 9th track sub-partition in the ith track partition; The 1st, 4th, and 7th track subpartitions are considered as the first side, the 2nd, 5th, and 8th track subpartitions are considered as the second side, and the 3rd, 6th, and 9th track subpartitions are considered as the third side; S14. Calculate the height of the trajectory sub-partition: Calculate the trajectory partition G i Average height of the first side Average height of the second side and the average height of the third side The expression is as follows: S15, first side and third side restriction judgment: Initialize height threshold Compare and The size of the value is based on the larger value and the height threshold The size relationship of determines the restriction of the first and third sides, and the expression is as follows: in, represents the restriction degree of the first side and the third side in the i-th trajectory partition; when When , it means that the GNSS observations in the trajectory sub-area on the first side or the third side are limited. When , it means that GNSS observations in the trajectory sub-area on the first side or the third side are not restricted; S16, second side restriction judgment: Initialize height difference threshold Compute the difference in the average height of the second side between adjacent track partitions: ΔG={ΔG1,...,ΔG i ,...,ΔG n-1 } Based on the obtained difference and the height difference threshold The relationship between the size of the second side is used to determine the restriction of the second side. The expression is as follows: in, represents the restriction degree of the second side in the i-th trajectory partition; when When , it means that the GNSS observations in the trajectory sub-area on the second side are limited. When , it means that the GNSS observations in the trajectory sub-area on the second side are not restricted; S17, Constrained Integration Calculation: Calculate the restriction degree of the i-th trajectory partition The expression is as follows: when When it is equal to 1 or 2, it means that the GNSS observation is limited in the i-th trajectory partition, and there is an observation-limited scenario. When it is equal to 0, it means that GNSS observation is not restricted in the i-th trajectory partition, and there is no observation restriction scenario; S18, restricted trajectory interval: By calculating the restriction degree of each trajectory partition, the restricted trajectory interval F is obtained 1,2,3 : in, They represent the degree of restriction of different trajectory partitions respectively; S19, the restricted trajectory interval F 1,2,3 Will be uploaded to the positioning tester.

3. The railway-specific satellite positioning test method for observation-restricted scenarios according to claim 1 is characterized in that: The step S2 comprises: S21. Get the train IMU position: The train IMU is located in the middle of the train, and the train IMU position P is calculated by the train IMU signal. IMU : Among them, m represents the number of train IMU signals during the positioning test period, Indicates the train IMU position corresponding to the i-th train IMU signal; S22. Obtain the GNSS position of the first-level train: The two GNSS receivers are located at the head and tail of the train respectively. The positions of the two GNSS receivers are obtained by receiving GNSS signals: Wherein, J1 represents the GNSS receiver at the front of the train, J2 represents the GNSS receiver at the rear of the train, and u represents the number of GNSS signals received by the GNSS receiver during the positioning test period. represents the position of J1 when it receives the i-th GNSS signal, represents the position of J2 when it receives the i-th GNSS signal; Depend on and Calculate the GNSS position of the first-level train in, represents the train position corresponding to the i-th GNSS signal; S23, upload the train IMU position and the first-level train GNSS position to the positioning tester.

4. The railway-specific satellite positioning test method for observation-restricted scenarios according to claim 2 is characterized in that: The step S3 comprises: S31. Determine the restricted track section that the train passes through: Initialize the positioning test time period T, obtain the average speed v of the train, and calculate the length of the test track interval: L=λ*T*v Where λ represents the length coefficient; Calculate the number of trajectory partitions: n=L / a Based on the current position of the train and the number of track partitions, determine the restricted track section that the train passes through during the positioning test period S32: Determine whether the train passes through an observation restricted scene based on the restricted trajectory interval: When all the values ​​of the restrictions in the restricted trajectory interval are zero, it means that during the positioning test period, the scenes passed by the train are all unrestricted scenes. The final position of the train is calculated by the first-level train GNSS position and the train IMU position, and step S6 is executed to determine the trajectory consistency. When there is a non-zero value of the restriction in the restricted trajectory interval, it means that during the positioning test period, there is an observation restricted scene in the scene where the train passes, and step S4 is executed to optimize the GNSS signal.

5. The railway-specific satellite positioning test method for observation-restricted scenarios according to claim 3 is characterized in that: The step S4 comprises: S41. Calculate the position residual between the train IMU position and the first-level train GNSS position: At each moment, the train IMU collects a train IMU signal and the GNSS receiver receives a GNSS signal; Get the train IMU position for t consecutive moments in the current positioning test period: Wherein, t is an integer and is less than T; Get the GNSS position of the first-level train for t consecutive moments in the current positioning test period: Due to the existence of observation-restricted scenarios, the train position calculated by the GNSS signal has deviations. Therefore, the set of position residuals ΔP between the train IMU position and the first-level train GNSS position at t consecutive moments in the current positioning test period is calculated, where the position residual ΔP at the i-th moment is i The expression is as follows: S42. Optimize the GNSS position of first-class trains: Based on the position residual, calculate the probability Pr that the GNSS position of the i-th first-level train is a valid GNSS signal i , the expression is as follows: Pr i =[(ΔP) max -ΔP i ] / [(ΔP) max -(ΔP) min ] Where (ΔP) max represents the maximum value in ΔP, (ΔP) min represents the minimum value in ΔP; Initialize the probability threshold α, and mark the GNSS position of the first-level train based on the relationship between the obtained probability and the probability threshold: When Pr i ≥α, the GNSS position of the i-th first-level train is marked as a valid GNSS signal. i <α, the GNSS position of the i-th first-level train is marked as an invalid GNSS signal; S43. Reconstruct the secondary train GNSS position using all valid GNSS signals.

6. The railway-specific satellite positioning test method for observation-restricted scenarios according to claim 1 is characterized in that: The step S5 comprises: Initialize adjustment coefficients β and γ, where β+γ=1; The final position of the train is calculated by the train IMU position and the secondary train GNSS position, where the final position of the i-th train is The expression is as follows: in, represents the GNSS position of the i-th secondary train.

7. The railway-specific satellite positioning test method for observation-restricted scenarios according to claim 1 is characterized in that: The step S6 comprises: S61, obtain the position P of the positioning tester C : Where w represents the number of secondary train GNSS positions; S62, trajectory consistency judgment: During the positioning test period, the cumulative error e between the final position of the train and the position of the positioning tester is calculated, and the expression is as follows: Initialize the cumulative error threshold ε, and output the trajectory consistency judgment result based on the relationship between the obtained cumulative error and the cumulative error threshold: When e≥ε, it means that the train positioning test trajectory is consistent with the actual train trajectory, and the satellite positioning is accurate. When e<ε, it means that the train positioning test trajectory is inconsistent with the actual train trajectory, and the satellite positioning is inaccurate.

8. A railway-specific satellite positioning test system for observation-restricted scenarios, characterized in that: Includes the following modules: Offline data processing module: obtain the height values ​​of the train running track and the surrounding environment of the train running track, divide the train running track into zones, calculate the restriction of each track zone based on the height values ​​in the track zone, obtain the restricted track interval and upload it to the positioning tester; Real-time data acquisition module: obtain the train IMU position through the train IMU, obtain the first-level train GNSS position through the train GNSS receiver, and upload the train IMU position and the first-level train GNSS position to the positioning tester; Restricted scene judgment module: Initialize the positioning test time period, and judge whether the train has passed through the observation restricted scene based on the current position of the train and the restricted trajectory section passed by the train during the positioning test time period. If the train has not passed through the observation restricted scene, run the trajectory consistency judgment module, otherwise run the GNSS signal optimization module; GNSS signal optimization module: calculates the position residual between the train IMU position and the first-level train GNSS position during the positioning test period, selects the valid first-level train GNSS position based on the position residual and constructs the second-level train GNSS position based on it; Trajectory consistency judgment module: The final position of the train is calculated by the train IMU position and the first-level train GNSS position, or the final position of the train is calculated by the train IMU position and the second-level train GNSS position, the position of the positioning tester is obtained, and the trajectory consistency judgment is completed by the final position of the train and the position of the positioning tester during the positioning test time period. To implement a railway-specific satellite positioning test method for observation-restricted scenarios as described in any one of claims 1-7.

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