Beidou satellite yaw attitude real-time estimation method based on inter-satellite link observation value

Abstract

The invention provides a Beidou satellite yaw attitude real-time estimation method based on an inter-satellite link observation value. The Beidou satellite yaw attitude real-time estimation method comprises the following steps: acquiring a Ka-band inter-satellite link bidirectional observation value of a Beidou third satellite; performing gross error elimination on the inter-satellite link observation value; performing epoch normalization on inter-satellite link bidirectional observation values of all satellites near each epoch point, and adding each pair of link bidirectional observation values to form a clock error-free combined observation quantity; an observation equation is established after error correction, and Ka antenna phase center deviation of each satellite is estimated per epoch; according to the relationship between the satellite yaw attitude change and the single-epoch Ka antenna phase center deviation, inversely solving the yaw attitude deviation of the satellite at each epoch moment; and adding the satellite attitude deviation and the nominal yaw attitude to obtain an estimated actual yaw attitude of the satellite. According to the method, the yawing attitude estimation precision of the Beidou third satellite can be improved, high-precision monitoring of the actual change condition of the satellite attitude is realized, and a reference is provided for satellite attitude modeling during an earth shadow period.

Description

Technical Field

[0001] The present invention relates to the field of satellite navigation technology, and in particular to a real-time estimation method for the yaw attitude of a Beidou satellite based on inter-satellite link observation values. Background Art

[0002] Satellite attitude describes the satellite's position in space. For an in-orbit navigation satellite, attitude control requires two conditions: first, the signal transmitting antenna must point toward the Earth's center to ensure effective signal reception for users on the ground; second, the axis of the satellite's solar array must be perpendicular to the sun to ensure sufficient energy supply. Therefore, the attitude of a navigation satellite can be described using a single angle parameter, called the yaw attitude angle.

[0003] To ensure the X and Z axes of the satellite's celestial coordinate system lie within the Sun-Earth-satellite plane, the navigation satellite attitude control system continuously adjusts the satellite's yaw angle. As a result, the satellite maintains a normal attitude, known as its nominal yaw attitude, most of the time. However, when the Sun, Earth, and satellite are approximately aligned, as is the case near midday and midnight, the satellite's yaw rate exceeds the maximum adjustment rate of the attitude control system, resulting in midday and midnight maneuvers. Furthermore, when some satellites enter Earth's shadow, their normal operation during the solar-sensitive period prevents them from maintaining their nominal attitude, leading to Earth's shadow maneuvers.

[0004] Accurately acquiring satellite attitude information is essential for high-precision orbit determination and positioning in satellite navigation systems. When satellite telemetry information is unavailable, observational data can be used to estimate the satellite's actual yaw angle on-orbit. This estimated yaw angle can be used to monitor satellite attitude changes and to validate or establish corresponding satellite attitude models. Navigation satellite yaw attitude estimation involves estimating geometric invariants in a celestial coordinate system to resolve the satellite's yaw angle. The vector formed by the satellite's center of mass and the phase center of the satellite antenna or laser reflector prism can be selected. However, due to limitations in laser satellite observation schedules, navigation satellites generally cannot be continuously tracked over the entire arc, and laser observations are relatively limited. Therefore, satellite antenna phase center estimation methods are commonly used. Existing methods all use single-epoch estimation of the L-band antenna phase center based on global tracking data. BeiDou-3 (BDS-3) satellites, in addition to L-band navigation antennas, also have Ka-band intersatellite link antennas. Intersatellite link observations enable continuous tracking over the entire arc, providing a new approach for yaw attitude estimation of BDS-3 satellites. Summary of the Invention

[0005] The present invention provides a real-time estimation method for the yaw attitude of Beidou satellites based on inter-satellite link observation values, which is used to solve the defect in the prior art that it is difficult to obtain and estimate the yaw attitude information of Beidou satellites with high precision, and realize accurate estimation of the yaw attitude of Beidou satellites.

[0006] In a first aspect, the present invention provides a method for real-time estimation of the yaw attitude of a Beidou satellite based on inter-satellite link observations, comprising: Obtain BeiDou-3 satellite Ka-band inter-satellite link two-way observation values ​​and auxiliary data; Detecting and eliminating gross errors in the inter-satellite link bidirectional observation values ​​to obtain processed inter-satellite link bidirectional observation values; Determining a preset epoch interval and a set epoch point, normalizing inter-satellite link two-way observation values ​​of all satellites that are half the preset epoch interval before and after the set epoch point to the set epoch point, and adding each pair of inter-satellite link two-way observation values ​​to obtain a clock-free combined observation value; The error correction of the clock-free combined observations is performed, and the observation equation is established. After linearizing the observation equation, the Ka antenna phase center deviation of each satellite is dynamically estimated epoch by epoch. Based on the mathematical relationship between the satellite yaw attitude change and the Ka antenna phase center deviation of a single epoch, the satellite attitude deviation of the actual satellite yaw attitude relative to the nominal satellite yaw attitude at each epoch is solved; The satellite attitude deviation is added to the satellite nominal yaw attitude at the corresponding moment to obtain the estimated actual yaw attitude of the satellite.

[0007] According to the present invention, a Beidou satellite yaw attitude real-time estimation method based on inter-satellite link observation values ​​is provided, wherein the inter-satellite link two-way observation values ​​include Ka-band two-way ranging observation values ​​formed between satellites and between satellites and ground anchor stations; The auxiliary data includes satellite broadcast ephemeris and inter-satellite link equipment delay calibration values.

[0008] According to a Beidou satellite yaw attitude real-time estimation method based on inter-satellite link observations provided by the present invention, gross errors are detected and eliminated on the inter-satellite link bidirectional observations to obtain processed inter-satellite link bidirectional observations, including: The gross errors of the bidirectional observation values ​​of the intersatellite link are detected and eliminated using the residual method or polynomial fitting method, where: The residual method includes calculating the theoretical intersatellite distance using the satellite orbits and clock errors predicted in the broadcast ephemeris and the pre-calibrated delay parameters, and subtracting the difference from the intersatellite link bidirectional observation value to obtain the observation value residual. If the residual exceeds a set threshold, the intersatellite link bidirectional observation value is determined to be a gross error and is eliminated. The polynomial fitting method includes performing polynomial fitting on the inter-satellite link bidirectional observation values ​​of multiple epochs to obtain a fitting curve. If the difference between the fitting curve and the current epoch observation value exceeds a set threshold, the inter-satellite link bidirectional observation value is determined to be a gross error and is eliminated.

[0009] According to a method for real-time estimation of Beidou satellite yaw attitude based on inter-satellite link observations provided by the present invention, a preset epoch interval and a set epoch point are determined, inter-satellite link two-way observations of all satellites that are half the preset epoch interval before and after the set epoch point are normalized to the set epoch point, and each pair of inter-satellite link two-way observations are added to obtain a clock-bias-free combined observation value, including: Performing bidirectional measurement on the BeiDou-3 intersatellite link using a time division multiple access system to obtain a forward intersatellite link ranging observation value and a backward intersatellite link ranging observation value, wherein the bidirectional measurement interval is the preset epoch interval; Performing satellite motion and clock error correction on forward intersatellite link ranging observation values ​​and backward intersatellite link ranging observation values ​​of each pair of intersatellite links using the predicted satellite orbits and clock errors, normalizing the values ​​to the set epoch point, and obtaining forward intersatellite link ranging observation values ​​and backward intersatellite link ranging observation values ​​at the same time; The forward inter-satellite link ranging observation value and the backward inter-satellite link ranging observation value at the same time are added together to obtain the clock-error-free combined observation value.

[0010] According to the present invention, a real-time estimation method for Beidou satellite yaw attitude based on inter-satellite link observations is provided. Error correction is performed on the clock-free combined observation quantity, an observation equation is established, and after linearizing the observation equation, the Ka antenna phase center deviation of each satellite is dynamically estimated epoch by epoch, including: The precise orbit determination is performed using clock-free combined observations, with the satellite orbit and hardware delay fixed as parameter estimates for precise orbit determination. The satellite antenna phase center deviation is dynamically estimated using a white noise model as the random parameter to be estimated. The observation equation and normal equation are established using all link observation values ​​normalized to the same epoch, and the sequential least squares or Kalman filter method is used to perform network adjustment to solve the Ka antenna phase center deviation of each satellite.

[0011] According to a method for real-time estimation of Beidou satellite yaw attitude based on inter-satellite link observation values ​​provided by the present invention, the observation equation includes:

[0012] Among them, A and B represent two BeiDou-3 satellites. for The inter-satellite link clock-free combined observation quantity between satellites A and B at the moment, and for The positions of satellites A and B at this moment, and is the rotation matrix of satellites A and B from the satellite-fixed system to the inertial system or the earth-fixed system, and for The phase center deviation of the Ka antenna of satellites A and B in the fixed system of the time satellite is: is the speed of light in vacuum, and is the intersatellite link equipment delay between satellites A and B, Measuring noise for intersatellite links.

[0013] According to a method for real-time estimation of Beidou satellite yaw attitude based on inter-satellite link observation values ​​provided by the present invention, the mathematical relationship includes:

[0014] in, is the deviation of the actual yaw angle of the satellite relative to the nominal yaw angle of the satellite at time t, and is the initial value of the Ka antenna phase center deviation in the x and y directions, and is the estimated value of the phase center deviation of Ka antenna in x and y directions at time t, The inverse tangent function returns the inverse tangent expressed in radians.

[0015] In a second aspect, the present invention further provides a Beidou satellite yaw attitude real-time estimation system based on inter-satellite link observation values, comprising: The acquisition module is used to obtain the inter-satellite link bidirectional observation values ​​and auxiliary data of the BeiDou-3 satellite Ka band; A pre-processing module is used to detect and eliminate gross errors in the inter-satellite link bidirectional observation values ​​to obtain processed inter-satellite link bidirectional observation values; a normalization module, configured to determine a preset epoch interval and a set epoch point, normalize inter-satellite link two-way observation values ​​of all satellites that are half the preset epoch interval before and after the set epoch point to the set epoch point, and add each pair of inter-satellite link two-way observation values ​​to obtain a clock-free combined observation value; The estimation module is used to perform error correction on the clock-free combined observations, establish the observation equation, linearize the observation equation, and dynamically estimate the Ka antenna phase center deviation of each satellite epoch by epoch; A solution module is used to solve the satellite attitude deviation of the actual satellite yaw attitude relative to the nominal satellite yaw attitude at each epoch based on the mathematical relationship between the satellite yaw attitude change and the Ka antenna phase center deviation of a single epoch; The calculation module is used to add the satellite attitude deviation to the satellite nominal yaw attitude at the corresponding moment to obtain the estimated actual yaw attitude of the satellite.

[0016] In a third aspect, the present invention also provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and runnable on the processor. When the processor executes the program, it implements any of the above-described methods for real-time estimation of the Beidou satellite yaw attitude based on inter-satellite link observation values.

[0017] In a fourth aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for real-time estimation of the yaw attitude of a Beidou satellite based on inter-satellite link observation values ​​as described above is implemented.

[0018] The present invention provides a method for real-time estimation of the yaw attitude of Beidou satellites based on inter-satellite link observations. By utilizing the good spatial geometric structure of Ka observations between Beidou-3 high-orbit and medium-orbit satellites, medium-orbit and medium-orbit satellites, and high-medium-orbit satellites and ground stations, the method solves the yaw attitude of Beidou satellites, thereby achieving high-precision satellite yaw attitude estimation. Compared with estimating satellite yaw attitude using L-band satellite-to-ground data, the method for real-time estimation of the yaw attitude based on inter-satellite link observations provided by the present invention does not contain satellite and receiver clock errors and ambiguity parameters during the data processing process, and is simpler to operate and has more reliable results. The yaw attitude estimation method provided by the present invention can be used to monitor the actual yaw attitude of Beidou satellites in real time, providing a basis for high-precision attitude modeling and precise orbit determination and positioning of Beidou satellites. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 1. It is a flow chart of a method for real-time estimation of Beidou satellite yaw attitude based on inter-satellite link observation values ​​provided by the present invention; Figure 2 This is a flow chart of intersatellite link observation value gross error detection provided by the present invention; Figure 3 This is the flow chart of the epoch normalization of intersatellite link two-way ranging observation values ​​provided by the present invention Figure 4 This is a flow chart of single epoch estimation of satellite Ka antenna phase center deviation provided by the present invention; Figure 5 This is a schematic structural diagram of a BeiDou satellite yaw attitude real-time estimation system based on inter-satellite link observations provided by the present invention; Figure 6 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0022] Figure 1 FIG. 1 is a flow chart of a method for real-time estimation of BeiDou satellite yaw attitude based on intersatellite link observations provided by an embodiment of the present invention. Figure 1 Shown, including: Step 100: Obtaining inter-satellite link bidirectional observation values ​​and auxiliary data of the BeiDou-3 satellite Ka band; Step 200: Detect and eliminate gross errors in the inter-satellite link bidirectional observation values ​​to obtain processed inter-satellite link bidirectional observation values; Step 300: Determine a preset epoch interval and a set epoch point, normalize inter-satellite link two-way observations of all satellites that are half the preset epoch interval before and after the set epoch point to the set epoch point, and add each pair of inter-satellite link two-way observations to obtain a clock-free combined observation value; Step 400: perform error correction on the clock-free combined observations, establish an observation equation, linearize the observation equation, and dynamically estimate the Ka antenna phase center bias of each satellite epoch by epoch; Step 500: Calculate the satellite attitude deviation of the actual satellite yaw attitude relative to the nominal satellite yaw attitude at each epoch based on the mathematical relationship between the satellite yaw attitude change and the Ka antenna phase center deviation of a single epoch. Step 600: Add the satellite attitude deviation to the satellite nominal yaw attitude at the corresponding moment to obtain an estimated actual yaw attitude of the satellite.

[0023] The embodiment of the present invention obtains the inter-satellite link bidirectional observation values ​​of the BeiDou-3 satellite Ka band; eliminates the gross errors of the inter-satellite link observation values; epoch-normalizes the inter-satellite link bidirectional observation values ​​of all satellites near each epoch point, and adds each pair of link bidirectional observation values ​​to form a clock-error-free combined observation quantity; establishes an observation equation after error correction, and estimates the Ka antenna phase center deviation of each satellite epoch by epoch; according to the relationship between the satellite yaw attitude change and the single epoch Ka antenna phase center deviation, the yaw attitude deviation of the satellite at each epoch is inversely solved; and the satellite attitude deviation is added to the nominal yaw attitude to obtain an estimated actual yaw attitude of the satellite.

[0024] The present invention can improve the estimation accuracy of the BeiDou-3 satellite's yaw attitude, achieve high-precision monitoring of actual changes in satellite attitude, and provide a benchmark for satellite attitude modeling during the Earth's shadow period.

[0025] Based on the above embodiment, the inter-satellite link observation values ​​of BeiDou-3 in step 100 include Ka-band two-way ranging observation values ​​formed between satellites and between satellites and ground anchor stations, and the auxiliary data include parameter values ​​such as satellite broadcast ephemeris and inter-satellite link equipment delay calibration values.

[0026] Based on the above embodiments, Figure 2 As shown, step 200 includes: The embodiment of the present invention can use the residual method and the polynomial fitting method to detect gross errors in Beidou inter-satellite link observation values.

[0027] The residual method uses the satellite orbits and clock errors predicted in the broadcast ephemeris and the pre-calibrated time delay parameters to calculate the theoretical satellite spacing, and then subtracts it from the inter-satellite link observation value to obtain the observation value residual. When the residual exceeds the set threshold, the observation value is considered to be a gross error. The polynomial fitting method obtains a fitting curve by performing polynomial fitting on the inter-satellite observation values ​​of multiple epochs. If the difference between the fitting curve and the observation value of the current epoch exceeds the set threshold, the inter-satellite link bidirectional observation value is determined to be a gross error.

[0028] If the gross error does not exceed the set threshold, the data is considered normal; otherwise, the data is discarded.

[0029] Based on the above embodiment, step 300 includes: In the embodiment of the present invention, the BeiDou-3 intersatellite link adopts a time division multiple access system for bidirectional measurement. Specifically, the time of the intersatellite bidirectional measurement is different, but the interval is no more than 3 seconds.

[0030] In order to combine the two-way observations to eliminate certain errors, it is necessary to normalize the two-way observations at different measurement times to the same time; use the predicted satellite orbits and clock errors to correct the satellite motion and clock error changes for the forward and backward ranging observations of each pair of links to normalize them to the same time. For example, set a certain epoch interval t (such as 60 seconds), and normalize the two-way observations of the inter-satellite links of all satellites within t / 2 before and after it to the set epoch point.

[0031] Then the forward and backward observation values ​​are added and combined to eliminate the satellite clock error information to obtain the inter-satellite link clock error-free combined observation value; the inter-satellite link two-way ranging observation value epoch normalization process is as follows: Figure 3 shown.

[0032] The clock-bias-free combined observations are obtained by using the broadcast ephemeris to normalize the two-way observations of each pair of links to the same time, and then adding and combining the two-way observations to eliminate the satellite clock error information to obtain the clock-bias-free combined observations of the inter-satellite links.

[0033] Based on the above embodiment, step 400 includes: The embodiment of the present invention first uses the clock-free combined observations of the BeiDou-3 inter-satellite link to perform precise orbit determination, then fixes the satellite orbit and hardware delay as parameter estimates in the precise orbit determination, and uses a white noise mode to dynamically estimate the satellite antenna phase center deviation as a random parameter to be estimated; when processing the data for parameter estimation, a data processing epoch interval of 60 seconds is set, and the BeiDou-3 inter-satellite link observation data within the next 30 seconds is normalized to the interval point, and then an observation model and a normal equation are established, and the least squares method is used for whole-network adjustment, and the Ka antenna phase center deviation of each satellite is solved in a single epoch; the satellite Ka antenna phase center deviation single epoch estimation process is as follows: Figure 4 shown.

[0034] The observation equation is:

[0035] Among them, A and B represent two BeiDou-3 satellites. for The inter-satellite link clock-free combined observation quantity between satellites A and B at the moment, and for The positions of satellites A and B at this moment, and is the rotation matrix of satellites A and B from the satellite-fixed system to the inertial system or the earth-fixed system, and for The phase center deviation of the Ka antenna of satellites A and B in the fixed system of the time satellite is: is the speed of light in vacuum, and is the intersatellite link equipment delay between satellites A and B, The noise of the inter-satellite link is measured; the satellite position and the delay of the inter-satellite link equipment are fixed to the estimated values ​​in advance, the rotation matrix from the satellite-fixed system to the inertial system or the Earth-fixed system is calculated using the nominal yaw attitude, and the parameter to be estimated is the phase center deviation of the satellite single epoch Ka antenna.

[0036] Furthermore, the estimation method of the single-epoch satellite Ka antenna phase center deviation is as follows: the observation model and normal equation are established using all link observation values ​​normalized to the same epoch, and the sequential least squares or Kalman filtering method is used for network adjustment to solve the single-epoch Ka antenna phase center deviation of each satellite.

[0037] Based on the above embodiment, the mathematical relationship in step 500 includes:

[0038] in, is the deviation of the actual satellite yaw angle relative to the nominal yaw angle at time t, and is the initial value of the Ka antenna phase center deviation in the x and y directions, and is the estimated value of the phase center deviation of Ka antenna in x and y directions at time t, The inverse tangent function returns the inverse tangent expressed in radians.

[0039] Finally, the satellite attitude deviation The estimated actual yaw attitude of the satellite is obtained by adding it to the nominal yaw attitude of the satellite at the corresponding moment.

[0040] The following describes the Beidou satellite yaw attitude real-time estimation system based on inter-satellite link observation values ​​provided by the present invention. The Beidou satellite yaw attitude real-time estimation system based on inter-satellite link observation values ​​described below and the Beidou satellite yaw attitude real-time estimation method based on inter-satellite link observation values ​​described above can be referenced to each other.

[0041] Figure 5 FIG is a schematic diagram of the structure of a BeiDou satellite yaw attitude real-time estimation system based on inter-satellite link observation values ​​provided by an embodiment of the present invention. Figure 5 As shown, it includes: an acquisition module 51, a preprocessing module 52, a naturalization module 53, an estimation module 54, a solution module 55 and a calculation module 56, wherein: The acquisition module 51 is used to obtain the inter-satellite link two-way observation values ​​and auxiliary data of the BeiDou-3 satellite Ka band; the pre-processing module 52 is used to detect and eliminate gross errors in the inter-satellite link two-way observation values ​​to obtain processed inter-satellite link two-way observation values; the normalization module 53 is used to determine the preset epoch interval and the set epoch point, normalize the inter-satellite link two-way observation values ​​of all satellites that are half the preset epoch interval before and after the set epoch point to the set epoch point, and add each pair of inter-satellite link two-way observation values ​​to obtain a clock-free combined observation value; the estimation module 54 is used to correct the error of the clock-free combined observation value, establish an observation equation, linearize the observation equation, and dynamically estimate the Ka antenna phase center deviation of each satellite epoch by epoch; the solution module 55 is used to solve the satellite attitude deviation of the actual satellite yaw attitude at each epoch relative to the nominal satellite yaw attitude based on the mathematical relationship between the satellite yaw attitude change and the Ka antenna phase center deviation of a single epoch; the calculation module 56 is used to add the satellite attitude deviation to the nominal satellite yaw attitude at the corresponding moment to obtain an estimated actual satellite yaw attitude.

[0042] Figure 6 An example of a physical structure diagram of an electronic device is shown below. Figure 6 As shown, the electronic device may include: a processor 610, a communication interface 620, a memory 630, and a communication bus 640, wherein the processor 610, the communication interface 620, and the memory 630 communicate with each other via the communication bus 640. The processor 610 may call the logic instructions in the memory 630 to execute a method for real-time estimation of Beidou satellite yaw attitude based on inter-satellite link observations, the method comprising: detecting and eliminating gross errors in the inter-satellite link bidirectional observations to obtain processed inter-satellite link bidirectional observations; Determine the preset epoch interval and the set epoch point, normalize the inter-satellite link two-way observation values ​​of all satellites with an interval of half the preset epoch interval before and after the set epoch point to the set epoch point, and add each pair of inter-satellite link two-way observation values ​​to obtain a clock-free combined observation quantity; perform error correction on the clock-free combined observation quantity, establish an observation equation, linearize the observation equation, and dynamically estimate the Ka antenna phase center deviation of each satellite epoch by epoch; according to the mathematical relationship between the satellite yaw attitude change and the Ka antenna phase center deviation of a single epoch, solve the satellite attitude deviation of the actual yaw attitude of the satellite relative to the nominal yaw attitude of the satellite at each epoch; add the satellite attitude deviation to the nominal yaw attitude of the satellite at the corresponding moment to obtain the estimated actual yaw attitude of the satellite.

[0043] Furthermore, the logic instructions in the aforementioned memory 630 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0044] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for real-time estimation of Beidou satellite yaw attitude based on inter-satellite link observations provided by the above methods is implemented. The method includes: detecting and eliminating gross errors in the inter-satellite link bidirectional observations to obtain processed inter-satellite link bidirectional observations; Determine the preset epoch interval and the set epoch point, normalize the inter-satellite link two-way observation values ​​of all satellites with an interval of half the preset epoch interval before and after the set epoch point to the set epoch point, and add each pair of inter-satellite link two-way observation values ​​to obtain a clock-free combined observation quantity; perform error correction on the clock-free combined observation quantity, establish an observation equation, linearize the observation equation, and dynamically estimate the Ka antenna phase center deviation of each satellite epoch by epoch; according to the mathematical relationship between the satellite yaw attitude change and the Ka antenna phase center deviation of a single epoch, solve the satellite attitude deviation of the actual yaw attitude of the satellite relative to the nominal yaw attitude of the satellite at each epoch; add the satellite attitude deviation to the nominal yaw attitude of the satellite at the corresponding moment to obtain the estimated actual yaw attitude of the satellite.

[0045] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0046] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for real-time estimation of BeiDou satellite yaw attitude based on inter-satellite link observations, characterized in that: include: Obtain BeiDou-3 satellite Ka-band inter-satellite link two-way observation values ​​and auxiliary data; Detecting and eliminating gross errors in the inter-satellite link bidirectional observation values ​​to obtain processed inter-satellite link bidirectional observation values; Determining a preset epoch interval and a set epoch point, normalizing inter-satellite link two-way observation values ​​of all satellites that are half the preset epoch interval before and after the set epoch point to the set epoch point, and adding each pair of inter-satellite link two-way observation values ​​to obtain a clock-free combined observation value; The error correction of the clock-free combined observations is performed, and the observation equation is established. After linearizing the observation equation, the Ka antenna phase center deviation of each satellite is dynamically estimated epoch by epoch. Based on the mathematical relationship between the satellite yaw attitude change and the Ka antenna phase center deviation of a single epoch, the satellite attitude deviation of the actual satellite yaw attitude relative to the nominal satellite yaw attitude at each epoch is solved; The satellite attitude deviation is added to the satellite nominal yaw attitude at the corresponding moment to obtain the estimated actual yaw attitude of the satellite.

2. The method for real-time estimation of BeiDou satellite yaw attitude based on intersatellite link observations according to claim 1, characterized in that: The intersatellite link two-way observation values ​​include Ka-band two-way ranging observation values ​​formed between satellites and between satellites and ground anchor stations; The auxiliary data includes satellite broadcast ephemeris and inter-satellite link equipment delay calibration values.

3. The method for real-time estimation of BeiDou satellite yaw attitude based on intersatellite link observations according to claim 1, characterized in that: The gross errors of the inter-satellite link bidirectional observation values ​​are detected and eliminated to obtain the processed inter-satellite link bidirectional observation values, including: The gross errors of the bidirectional observation values ​​of the intersatellite link are detected and eliminated using the residual method or polynomial fitting method, where: The residual method includes calculating the theoretical intersatellite distance using the satellite orbits and clock errors predicted in the broadcast ephemeris and the pre-calibrated delay parameters, and subtracting the difference from the intersatellite link bidirectional observation value to obtain the observation value residual. If the residual exceeds a set threshold, the intersatellite link bidirectional observation value is determined to be a gross error and is eliminated. The polynomial fitting method includes performing polynomial fitting on the inter-satellite link bidirectional observation values ​​of multiple epochs to obtain a fitting curve. If the difference between the fitting curve and the current epoch observation value exceeds a set threshold, the inter-satellite link bidirectional observation value is determined to be a gross error and is eliminated.

4. The method for real-time estimation of BeiDou satellite yaw attitude based on intersatellite link observations according to claim 1, characterized in that: Determining a preset epoch interval and a set epoch point, normalizing inter-satellite link two-way observation values ​​of all satellites that are half the preset epoch interval before and after the set epoch point to the set epoch point, and adding each pair of inter-satellite link two-way observation values ​​to obtain a clock-free combined observation value, including: Performing bidirectional measurement on the BeiDou-3 intersatellite link using a time division multiple access system to obtain a forward intersatellite link ranging observation value and a backward intersatellite link ranging observation value, wherein the bidirectional measurement interval is the preset epoch interval; Performing satellite motion and clock error correction on forward intersatellite link ranging observation values ​​and backward intersatellite link ranging observation values ​​of each pair of intersatellite links using the predicted satellite orbits and clock errors, normalizing the values ​​to the set epoch point, and obtaining forward intersatellite link ranging observation values ​​and backward intersatellite link ranging observation values ​​at the same time; The forward inter-satellite link ranging observation value and the backward inter-satellite link ranging observation value at the same time are added together to obtain the clock-error-free combined observation value.

5. The method for real-time estimation of BeiDou satellite yaw attitude based on inter-satellite link observations according to claim 1, characterized in that: The error correction of the clock-free combined observations is performed, and the observation equation is established. After linearizing the observation equation, the Ka antenna phase center deviation of each satellite is dynamically estimated epoch by epoch, including: The precise orbit determination is performed using clock-free combined observations, with the satellite orbit and hardware delay fixed as parameter estimates for precise orbit determination. The satellite antenna phase center deviation is dynamically estimated using a white noise model as the random parameter to be estimated. The observation equation and normal equation are established using all link observation values ​​normalized to the same epoch, and the sequential least squares or Kalman filter method is used to perform network adjustment to solve the Ka antenna phase center deviation of each satellite.

6. The method for real-time estimation of BeiDou satellite yaw attitude based on inter-satellite link observations according to claim 5, characterized in that: The observation equation includes: Among them, A and B represent two BeiDou-3 satellites. for The inter-satellite link clock-free combined observation quantity between satellites A and B at the moment, and for The positions of satellites A and B at this moment, and is the rotation matrix of satellites A and B from the satellite-fixed system to the inertial system or the earth-fixed system, and for The phase center deviation of the Ka antenna of satellites A and B in the fixed system of the time satellite is: is the speed of light in vacuum, and is the intersatellite link equipment delay between satellites A and B, Measuring noise for intersatellite links.

7. The method for real-time estimation of BeiDou satellite yaw attitude based on inter-satellite link observations according to claim 1, characterized in that: The mathematical relationships include: in, is the deviation of the actual yaw angle of the satellite relative to the nominal yaw angle of the satellite at time t, and is the initial value of the Ka antenna phase center deviation in the x and y directions, and is the estimated value of the phase center deviation of Ka antenna in x and y directions at time t, The inverse tangent function returns the inverse tangent expressed in radians.

8. A BeiDou satellite yaw attitude real-time estimation system based on inter-satellite link observations, characterized in that: include: The acquisition module is used to obtain the inter-satellite link bidirectional observation values ​​and auxiliary data of the BeiDou-3 satellite Ka band; A pre-processing module is used to detect and eliminate gross errors in the inter-satellite link bidirectional observation values ​​to obtain processed inter-satellite link bidirectional observation values; a normalization module, configured to determine a preset epoch interval and a set epoch point, normalize inter-satellite link two-way observation values ​​of all satellites that are half the preset epoch interval before and after the set epoch point to the set epoch point, and add each pair of inter-satellite link two-way observation values ​​to obtain a clock-free combined observation value; The estimation module is used to perform error correction on the clock-free combined observations, establish the observation equation, linearize the observation equation, and dynamically estimate the Ka antenna phase center deviation of each satellite epoch by epoch; A solution module is used to solve the satellite attitude deviation of the actual satellite yaw attitude relative to the nominal satellite yaw attitude at each epoch based on the mathematical relationship between the satellite yaw attitude change and the Ka antenna phase center deviation of a single epoch; The calculation module is used to add the satellite attitude deviation to the satellite nominal yaw attitude at the corresponding moment to obtain the estimated actual yaw attitude of the satellite.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method for real-time estimation of Beidou satellite yaw attitude based on inter-satellite link observation values ​​as described in any one of claims 1 to 7 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for real-time estimation of Beidou satellite yaw attitude based on inter-satellite link observation values ​​as claimed in any one of claims 1 to 7 is implemented.

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