Method for estimating zero bias of inertial gyroscope in track inspection trolley

Abstract

This application relates to the field of navigation, specifically to a method for estimating the zero bias of an inertial navigation gyroscope for a track inspection trolley. The method includes: for multiple total station locations, acquiring the arrival time of the track inspection trolley at each total station location, the station position coordinates of each total station location, and the inertial navigation system's calculated position for each total station location; for any discontinuity between two total stations, calculating the total station location vector corresponding to the discontinuity based on the coordinates of the two stations, calculating the inertial navigation system's calculated position vector corresponding to the discontinuity based on the two inertial navigation system's calculated positions, and calculating the installation deflection angle corresponding to the discontinuity based on the station location vector and the inertial navigation system's calculated vector; and estimating the gyroscope zero bias based on the rate of change of the installation deflection angle with the arrival time. The inertial navigation gyroscope zero bias estimation method for a track inspection trolley provided in this application achieves the technical effect of improving the accuracy of gyroscope zero bias estimation results under special environments and enhancing the environmental applicability of the gyroscope zero bias estimation method.

Description

Technical Field

[0001] This application relates to the field of navigation, specifically to a method for estimating the zero bias of an inertial gyroscope for a track inspection trolley. Background Technology

[0002] An inertial navigation system (INS) is a navigation technology that operates completely autonomously without relying on external signals. It measures the linear acceleration and angular velocity of an object by using accelerometers and gyroscopes mounted on the vehicle. Using initial position, velocity, and attitude information, it calculates the vehicle's current real-time position, velocity, and attitude through two integration operations. It has advantages such as strong stealth, good anti-interference ability, and high data update rate, and is widely used in submarines, aircraft, missiles, and spacecraft.

[0003] In an inertial navigation system, gyro bias refers to a non-zero constant error or slowly changing quantity in the output signal of a gyroscope in an ideal static state (i.e., without actual angular velocity input). It is the result of the combined effects of factors such as internal friction of the gyroscope, electronic noise, temperature drift, and manufacturing defects. This seemingly small error is extremely harmful in navigation calculations because the system needs to perform time integration on the angular velocity to calculate the attitude. A constant bias will cause the attitude angle error to accumulate linearly over time, which will lead to the incorrect decomposition of gravitational acceleration and cause serious consequences such as the velocity error increasing quadratically over time and the position error diverging cubically over time. It is the most important factor limiting the long-term working accuracy of inertial navigation systems.

[0004] The standard method for accurately measuring gyroscope zero bias is to fix the gyroscope or inertial measurement unit (IMU) on a high-precision turntable and keep it strictly still in a precise temperature-controlled laboratory environment, and collect output data for tens of minutes or even hours. The constant zero bias is estimated by calculating the arithmetic mean of these static data, so as to separate and quantify different types of error sources such as zero bias instability and angle random walk.

[0005] However, in practical applications, it is necessary to determine and compensate for gyroscope bias in real time during the operation of inertial navigation systems. To address this need, existing technologies often employ Kalman filtering combined with external reference sources for real-time estimation and compensation during the dynamic operation of the inertial navigation system. However, in special operating environments such as tunnels, underground spaces, and areas with severe obstruction, external reference sources are difficult to obtain. This results in the accuracy of real-time estimation of gyroscope bias in existing technologies being significantly affected by the environment, leading to poor applicability of existing gyroscope bias estimation methods and low accuracy in these special environments. Summary of the Invention

[0006] In view of this, it is necessary to provide a method for estimating the zero bias of the inertial navigation gyroscope for a track inspection trolley, so as to improve the accuracy of the zero bias estimation results under special environments and enhance the environmental applicability of the zero bias estimation method.

[0007] To address the aforementioned technical problems, this application provides a method for estimating the zero bias of an inertial gyroscope for a track inspection trolley, comprising: For multiple total station locations, the arrival time of the track inspection trolley at each total station location, the station location coordinates of each total station location, and the inertial navigation calculated position of each total station location are obtained respectively. For each station segment, the station position coordinate vector corresponding to the station segment is calculated based on the station position coordinates, the inertial navigation system (INS) calculated position vector corresponding to the station segment is calculated based on the INS calculated position, and the installation deflection angle corresponding to the station segment is calculated based on the station position coordinate vector and the INS calculated position vector. The station segment is the spatial segment between two adjacent total station stations. The gyroscope zero bias of the inertial navigation device is estimated based on the rate of change of the installation deflection angle with the arrival time.

[0008] In one possible embodiment, estimating the gyro zero bias of the inertial navigation device based on the rate of change of the installation deflection angle with the arrival time includes: For each of the station segments, the fitting time corresponding to the station segment is determined according to the arrival time, resulting in multiple installation deflection angle-fitting time data pairs; A linear fit is performed on all the installation deflection angle-fitting time data pairs to obtain a fitted straight line; The slope of the fitted straight line is used as the rate of change, and the gyroscope zero bias of the inertial navigation device is estimated based on the slope.

[0009] In one possible embodiment, the installation skew angle includes a heading installation skew angle and / or a pitch installation skew angle, the installation skew angle-fitting time data pair includes a heading installation skew angle-fitting time data pair and / or a pitch installation skew angle-fitting time data pair, and the step of estimating the gyro zero bias of the inertial navigation device based on the rate of change of the installation skew angle with the sampling time includes: Linear fitting is performed on all the aforementioned heading installation angle-fitting time data pairs to obtain a heading fitting line. The horizontal gyroscope zero bias of the inertial navigation device in the horizontal plane direction is estimated based on the slope of the heading fitting line. And / or perform linear fitting on all pitch installation tilt angle-fitting time data pairs to obtain a pitch fitting line, and estimate the vertical gyroscope zero tilt of the inertial navigation device in the vertical direction based on the slope of the pitch fitting line. The horizontal gyroscope zero bias and the vertical gyroscope zero bias together constitute the gyroscope zero bias of the inertial navigation device.

[0010] In one possible embodiment, calculating the installation deflection angle corresponding to the inter-site segment based on the site location coordinate vector and the inertial navigation calculated position vector includes: Projecting the station location coordinate vector onto the horizontal plane yields the horizontally projected station location coordinate component vector; projecting the inertial navigation calculated location vector onto the horizontal plane yields the horizontally projected inertial navigation component vector. The horizontal azimuth angle of the station position coordinates corresponding to the station position coordinate vector is calculated based on the horizontal projection station position coordinate component vector, and the horizontal azimuth angle of the inertial navigation system corresponding to the inertial navigation system calculated based on the horizontal projection inertial navigation component vector. The difference between the horizontal azimuth of the station location coordinates and the horizontal azimuth of the inertial navigation system is used as the heading installation angle.

[0011] In one possible embodiment, estimating the horizontal gyroscope zero bias of the inertial navigation device in the horizontal plane direction based on the slope of the heading fitted straight line includes: Obtain the current latitude value of the inertial navigation device based on the formula. The zero bias of the horizontal gyroscope was calculated. ,in, Let be the slope of the straight line fitted to the heading. The current latitude value.

[0012] In one possible embodiment, calculating the installation deflection angle corresponding to the inter-site segment based on the site location coordinate vector and the inertial navigation calculated position vector includes: Calculate the horizontal angle between the station position coordinate vector and the station position coordinate vector on the horizontal plane, and calculate the horizontal angle between the inertial navigation calculated position vector and the inertial navigation calculated position vector on the horizontal plane; The difference between the horizontal angle of the station location coordinate vector and the horizontal angle of the inertial navigation calculated location vector is taken as the pitch installation angle.

[0013] In one possible embodiment, obtaining the inertial navigation-calculated position includes: For any current total station, obtain the current arrival time corresponding to the current total station, the previous total station adjacent to the current total station, the previous inertial navigation system (INS) calculated position corresponding to the previous total station, and the previous arrival time corresponding to the previous total station. Calculate the INS calculated position corresponding to the current total station based on the current arrival time, the previous INS calculated position, and the previous arrival time.

[0014] The beneficial effects of this application are: Compared with related technologies, the inertial navigation gyroscope zero bias estimation method for the track inspection trolley provided in this application pre-sets multiple total station locations, acquires the arrival time of the track inspection trolley at each total station location, the station position coordinates of each total station location, and the inertial navigation calculated position of each total station location. For the station segment between two adjacent total stations, the station position coordinate vector corresponding to the station segment is calculated based on the station position coordinates, and the inertial navigation calculated position vector corresponding to the station segment is calculated based on the inertial navigation calculated position. The installation deflection angle corresponding to the station segment is calculated based on the station position coordinate vector and the inertial navigation calculated position vector. Finally, the gyroscope zero bias of the inertial navigation device is estimated based on the rate of change of the installation deflection angle over time, utilizing sparse... By setting multiple total stations, the "installation deflection angle" that does not change with the movement of the inertial navigation device is calculated. The installation deflection angle should be a constant value when there is no error. However, the gyro zero bias will cause the installation deflection angle to drift linearly with time. By monitoring the drift rate of this deflection angle in multiple intervals, the gyro zero bias of the inertial navigation device can be accurately estimated by inversion. This application ingeniously transforms the internal error of the inertial navigation device, which is difficult to observe directly, into a geometric change that can be observed through external sparse points. The accurate estimation of the gyro zero bias of the inertial navigation device can be achieved solely through the position change of the inertial navigation device, without relying on high-precision external observation data. This achieves the technical effect of improving the accuracy of the gyro zero bias estimation results in special environments and improving the environmental applicability of the gyro zero bias estimation method. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart illustrating the inertial gyroscope zero-bias estimation method for the track inspection trolley provided in this embodiment of the application. Figure 2 This is a flowchart illustrating the process of determining the heading installation deflection angle in the inertial gyroscope zero-bias estimation method for the track inspection trolley provided in this embodiment of the application. Figure 3 This is a schematic diagram of the linear fitting result of the heading installation angle-fitting time in the inertial gyroscope zero-bias estimation method for the track inspection trolley provided in the embodiments of this application. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0018] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0019] The terms "first," "second," etc., used in the embodiments of this application are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a technical feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0020] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] This application provides a method for estimating the zero bias of the inertial gyroscope in a track inspection trolley. Please refer to [reference needed]. Figure 1 The inertial gyroscope zero-bias estimation method for the track inspection trolley provided in this application includes: Step S101: For multiple total station stations, obtain the arrival time of the track inspection trolley at each total station, the station position coordinates of each total station, and the inertial navigation calculated position of each total station.

[0022] In this step, the total station, a precision instrument integrating angle and distance measurement functions, is used for engineering surveying. The total station's designated station point serves as the benchmark for the surveying operation. It is obtained as follows: After the track inspection trolley moves to the pre-set station area and stops, the total station mounted on the trolley uses the CPIII control points laid out on both sides of the track as the measurement benchmark. The resection method is used to complete the station calculation, and the determined benchmark point is the total station's designated station point. The total station then uses this station to accurately measure the current position of the track inspection trolley. When the track inspection trolley moves to any total station's designated station, the time of arrival is recorded as the arrival time. Then, the previous arrival time corresponding to the previous total station setting point, the current arrival time corresponding to the current total station setting point, and the previous inertial navigation system (INS) estimated position corresponding to the previous total station setting point (the initial station directly uses the station position coordinates as the INS estimated position) can be obtained. Based on these parameters, the possible position of the track inspection trolley at the current time, predicted by the INS, is calculated using the INS navigation algorithm of the inertial navigation equipment and used as the INS estimated position of the current total station setting point. In other words, the INS estimated position of the current total station setting point is the position calculated based on the INS navigation algorithm of the inertial navigation equipment. The deviation between the calculated INS estimated position and the actual station position coordinates is related to the gyroscope zero bias of the INS. Subsequently, the estimated value of the gyroscope zero bias can be calculated based on the INS estimated position and the actual station position coordinates.

[0023] Step S102: For each station segment, calculate the station position coordinate vector corresponding to the station segment based on the station position coordinates, and calculate the inertial navigation calculated position vector corresponding to the station segment based on the inertial navigation calculated position.

[0024] In this step, the station interval is the spatial interval between two adjacent total station stations. There are n station intervals. , , ..., , These correspond to the coordinates of the respective station locations. , , ..., , Arrival times at each station location For example, the station interval is [ ]、[ ...[ Based on this, station intervals are set. The corresponding inertial navigation calculated position is .

[0025] Thus, for any i-th station interval [ ], its corresponding sampling vector Setting up stations for total station Pointing to the total station setting station The vector is expressed by the formula: Similarly, its corresponding inertial navigation derivation vector for Corresponding inertial navigation calculated position point to Corresponding inertial navigation calculated position The vector is expressed by the formula: .

[0026] Step S103: Calculate the installation deflection angle corresponding to the station segment based on the station location coordinate vector and the inertial navigation-derived position vector.

[0027] In this step, in a spatial coordinate system, such as the North-East-Down coordinate system, E and D are the three coordinate axes in the North-East-Down coordinate system. The N-axis (North) points towards the geographic North Pole; the E-axis (East) points towards geographic due east; and the D-axis (Down) is perpendicular to the local horizontal plane and points towards the Earth's center. The installation deflection angle can be specifically decomposed into the heading installation deflection angle on the NE-axis plane (horizontal plane) and the pitch installation deflection angle in the D-axis direction (vertical direction).

[0028] For the heading installation angle, please refer to... Figure 2 Determining the heading installation angle specifically includes: Step S201: Project the station location coordinate vector onto the horizontal plane to obtain the horizontally projected station location coordinate component vector, and project the inertial navigation calculated vector onto the horizontal plane to obtain the horizontally projected inertial navigation component vector.

[0029] In this step, the station location coordinate vector is decomposed along the coordinate axes to obtain three component vectors, namely... Based on this, the horizontal projection station location coordinate component vectors That is Similarly, the horizontally projected inertial navigation component vector That is .

[0030] Step S202: Calculate the horizontal azimuth angle of the station position coordinates corresponding to the station position coordinate vector based on the horizontal projection station position coordinate component vector, and calculate the horizontal azimuth angle of the inertial navigation system corresponding to the inertial navigation system calculated position vector based on the horizontal projection inertial navigation component vector.

[0031] In this step, the horizontal azimuth angle of the station location coordinates and the horizontal azimuth angle of the inertial navigation system are calculated based on the angle calculation formula in trigonometric functions. Specifically, the horizontal azimuth angle of the station location coordinates corresponding to the station location coordinate vector is... ; Inertial navigation horizontal azimuth angle .

[0032] Step S203: Use the difference between the horizontal azimuth of the station location coordinates and the horizontal azimuth of the inertial navigation system as the heading installation deflection angle.

[0033] Specifically, in this step, the horizontal azimuth angle of the station location coordinates and the horizontal azimuth angle of the inertial navigation system are directly subtracted to obtain the heading installation deflection angle. .

[0034] Determining the pitch installation angle specifically includes: calculating the horizontal angle between the station position coordinate vector and the station position coordinate vector on the horizontal plane, and calculating the horizontal angle between the inertial navigation system (INS) calculated position vector and the INS calculated position vector on the horizontal plane; the difference between the horizontal angles of the station position coordinate vector and the INS calculated position vector is taken as the pitch installation angle. The specific formula is as follows: First, calculate the magnitude of each vector: Then calculate the angles (pitch angles) between each vector and the horizontal plane: Then the pitch installation angle for: .

[0035] Step S104: Estimate the gyroscope zero bias of the inertial navigation device based on the rate of change of the installation bias angle with the arrival time.

[0036] In this step, for each station segment [ The corresponding arrival time period[ Determine the station intervals. The corresponding fitting time (For example, the time period to get to the station) The midpoint of ], i.e. Multiple installation deflection angle-fitting time data pairs were obtained. A linear fit was performed on all installation deflection angle-fitting time data pairs to obtain a fitted straight line. The slope of the fitted straight line was used as the rate of change, and the gyro zero bias of the inertial navigation device was estimated based on the slope. As mentioned above, the installation deflection angle includes the heading installation deflection angle. and / or pitch installation angle Installation yaw angle-fitting time data pairs include heading installation yaw angle-fitting time data pairs. - and / or pitch installation angle - fitting time data pair - Then, the corresponding data for the installation yaw angle and fitting time can be applied to all headings. - The set Perform linear fitting, such as Figure 3 As shown, the heading fitting line is obtained, and the slope of the heading fitting line is used to determine the heading. Estimate the horizontal gyroscope zero bias of the inertial navigation device in the horizontal plane. This involves installing bias angle-fitting time data for all headings. - The set Performing linear fitting can be simplified to applying a set of formulas. , Solving for the slope of the fitted heading line yields the solution. ,in, Here is the theoretical value of the heading installation angle, and here are the constant values ​​corresponding to each inertial navigation device. The rate of change of the heading installation angle. To find the slope of the fitted heading line, and These are the theoretical and actual solved values ​​of the rate of change of the heading installation angle, respectively. For reference time, set a constant value. This represents the observed noise and the constant value corresponding to the inertial navigation device. Finally, according to the formula... Estimating the horizontal gyroscope zero bias of an inertial navigation device in the horizontal plane. D is the celestial axis.

[0037] Using the same method, all pitch installation angle-fitting time data pairs were analyzed. - The set Performing linear fitting can be simplified to applying a set of formulas. , Solving for the slope of the fitted heading line yields the solution. ,in, Here, represents the theoretical value for the pitch installation angle, and represents the constant value corresponding to each inertial navigation device. The rate of change of the pitch installation angle, To find the slope of the fitted heading line, and These are the theoretical and actual calculated values ​​of the rate of change of the pitch installation angle, respectively. As a reference time, a constant value is set. This represents the observed noise and the constant value corresponding to the inertial navigation device. Finally, according to the formula... , Estimating the pitch gyroscope zero bias of an inertial navigation device in the horizontal direction. and N is the N-axis pointing towards the geographic North Pole, and E is the E-axis pointing towards geographic due east.

[0038] Finally, use a horizontal gyroscope with zero bias. and vertical gyroscope zero bias and Together, they constitute the zero bias of the gyroscope in an inertial navigation device.

[0039] Compared with related technologies, the inertial navigation gyroscope zero bias estimation method for the track inspection trolley provided in this embodiment pre-sets multiple total station locations, acquires the arrival time of the track inspection trolley at each total station location, the station position coordinates of each total station location, and the inertial navigation calculated position of each total station location. For the station segment between two adjacent total stations, the station position coordinate vector corresponding to the station segment is calculated based on the station position coordinates, and the inertial navigation calculated position vector corresponding to the station segment is calculated based on the inertial navigation calculated position. The installation deflection angle corresponding to the station segment is calculated based on the station position coordinate vector and the inertial navigation calculated position vector. Finally, the gyroscope zero bias of the inertial navigation device is estimated based on the rate of change of the installation deflection angle over time, utilizing sparse... By setting up multiple total stations with sparse data points, the "installation deflection angle" that does not change with the movement of the inertial navigation device is calculated. The installation deflection angle should be a constant value when there is no error. However, the gyro zero bias will cause the installation deflection angle to drift linearly with time. By monitoring the drift rate of this deflection angle in multiple intervals, the gyro zero bias of the inertial navigation device can be accurately estimated by inversion. This application ingeniously transforms the internal error of the inertial navigation device, which is difficult to observe directly, into a geometric change that can be observed through external sparse points. The accurate estimation of the gyro zero bias of the inertial navigation device can be achieved solely through the positional change of the inertial navigation device, without relying on high-precision external observation data. This achieves the technical effect of improving the accuracy of the gyro zero bias estimation results in special environments and improving the environmental applicability of the gyro zero bias estimation method.

[0040] The above provides a detailed description of the inertial gyroscope zero-bias estimation method for the track inspection trolley provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for estimating the zero bias of an inertial gyroscope in a track inspection trolley, characterized in that, include: For multiple total station locations, the arrival time of the track inspection trolley at each total station location, the station location coordinates of each total station location, and the inertial navigation calculated position of each total station location are obtained respectively. For each station segment, the station position coordinate vector corresponding to the station segment is calculated based on the station position coordinates, the inertial navigation system (INS) calculated position vector corresponding to the station segment is calculated based on the INS calculated position, and the installation deflection angle corresponding to the station segment is calculated based on the station position coordinate vector and the INS calculated position vector. The station segment is the spatial segment between two adjacent total station stations. The gyroscope zero bias of the inertial navigation device is estimated based on the rate of change of the installation deflection angle with the arrival time.

2. The method for estimating the zero bias of the inertial gyroscope in the track inspection trolley according to claim 1, characterized in that, The step of estimating the gyroscope zero bias of the inertial navigation device based on the rate of change of the installation deflection angle with the arrival time includes: For each of the station segments, the fitting time corresponding to the station segment is determined according to the arrival time, resulting in multiple installation deflection angle-fitting time data pairs; A linear fit is performed on all the installation deflection angle-fitting time data pairs to obtain a fitted straight line; The slope of the fitted straight line is used as the rate of change, and the gyroscope zero bias of the inertial navigation device is estimated based on the slope.

3. The method for estimating the zero bias of the inertial gyroscope for the track inspection trolley according to claim 2, characterized in that, The installation skew angle includes the heading installation skew angle and / or the pitch installation skew angle, and the installation skew angle-fitting time data pair includes the heading installation skew angle-fitting time data pair and / or the pitch installation skew angle-fitting time data pair. The step of estimating the gyro zero bias of the inertial navigation device based on the rate of change of the installation skew angle with the sampling time includes: Linear fitting is performed on all the aforementioned heading installation angle-fitting time data pairs to obtain a heading fitting line. The horizontal gyroscope zero bias of the inertial navigation device in the horizontal plane direction is estimated based on the slope of the heading fitting line. And / or perform linear fitting on all pitch installation tilt angle-fitting time data pairs to obtain a pitch fitting line, and estimate the vertical gyroscope zero tilt of the inertial navigation device in the vertical direction based on the slope of the pitch fitting line. The horizontal gyroscope zero bias and the vertical gyroscope zero bias together constitute the gyroscope zero bias of the inertial navigation device.

4. The method for estimating the zero bias of the inertial gyroscope for the track inspection trolley according to claim 3, characterized in that, The step of calculating the installation deflection angle corresponding to the inter-site segment based on the site location coordinate vector and the inertial navigation calculated position vector includes: Projecting the station location coordinate vector onto the horizontal plane yields the horizontally projected station location coordinate component vector; projecting the inertial navigation calculated location vector onto the horizontal plane yields the horizontally projected inertial navigation component vector. The horizontal azimuth angle of the station position coordinates corresponding to the station position coordinate vector is calculated based on the horizontal projection station position coordinate component vector, and the horizontal azimuth angle of the inertial navigation system corresponding to the inertial navigation system calculated based on the horizontal projection inertial navigation component vector. The difference between the horizontal azimuth of the station location coordinates and the horizontal azimuth of the inertial navigation system is used as the heading installation angle.

5. The method for estimating the zero bias of the inertial gyroscope for the track inspection trolley according to claim 4, characterized in that, The step of estimating the horizontal gyroscope zero bias of the inertial navigation device in the horizontal plane based on the slope of the heading fitted straight line includes: Obtain the current latitude value of the inertial navigation device based on the formula. The zero bias of the horizontal gyroscope was calculated. ,in, Let be the slope of the straight line fitted to the heading. The current latitude value.

6. The method for estimating the zero bias of the inertial gyroscope for the track inspection trolley according to claim 3, characterized in that, The step of calculating the installation deflection angle corresponding to the inter-site segment based on the site location coordinate vector and the inertial navigation calculated position vector includes: Calculate the horizontal angle between the station position coordinate vector and the station position coordinate vector on the horizontal plane, and calculate the horizontal angle between the inertial navigation calculated position vector and the inertial navigation calculated position vector on the horizontal plane; The difference between the horizontal angle of the station location coordinate vector and the horizontal angle of the inertial navigation calculated location vector is taken as the pitch installation angle.

7. The method for estimating the zero bias of the inertial gyroscope for the track inspection trolley according to any one of claims 1 to 6, characterized in that, Obtaining the inertial navigation system's calculated position includes: For any current total station, obtain the current arrival time corresponding to the current total station, the previous total station adjacent to the current total station, the previous inertial navigation system (INS) calculated position corresponding to the previous total station, and the previous arrival time corresponding to the previous total station. Calculate the INS calculated position corresponding to the current total station based on the current arrival time, the previous INS calculated position, and the previous arrival time.

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