Space target orbit prediction time deviation compensation method and system based on doppler sequence matching

Abstract

The application discloses a space target orbit prediction time deviation compensation method and system based on Doppler sequence matching, and the method comprises the following steps: acquiring a measured Doppler sequence and a corresponding timestamp set of a space target in a visible arc segment of a station; acquiring a theoretical Doppler sequence corresponding to the station based on a TLE of the space target and the timestamp set of the measured Doppler sequence through an SGP4 orbit prediction model; aligning the theoretical Doppler sequence and the measured Doppler sequence in a time reference; constructing a cost function model with a time domain translation amount as an independent variable and a Doppler sequence residual square sum as an optimization target, and performing global search to obtain an optimal time deviation; keeping the TLE unchanged, and compensating a prediction time based on the optimal time deviation. The application can effectively improve the accuracy of space target communication modeling such as satellites, meanwhile, has the characteristics of low calculation overhead, high prediction accuracy, strong model stability and the like, and is suitable for high-frequency real-time tracking and guiding requirements.

Description

Technical Field

[0001] This invention belongs to the field of space target orbit prediction and aerospace telemetry and control technology, specifically involving a method and system for compensating for time deviations in space target orbit prediction based on Doppler sequence matching. Background Technology

[0002] Space target surveillance and orbit prediction technology is a core support in the modern aerospace telemetry and control field, mainly responsible for the real-time calculation and prediction of the orbits of low-Earth orbit (LEO) space targets such as LEO satellites and space debris. With the rapid deployment of LEO satellite constellations and the surge in the number of space debris, the requirements for target orbit prediction accuracy, computing power, and high-frequency real-time output are constantly increasing.

[0003] Due to the complex perturbation factors such as upper atmospheric drag and the Earth's non-spherical gravity, orbit prediction errors of low-Earth orbit (LEO) satellites accumulate rapidly over time. In the waveform design and hardware channel simulation of the physical layer of satellite-to-ground communication, the high-speed motion of LEO satellites leads to extremely drastic time-varying Doppler shifts and time delay drifts. To ensure the absolute continuity of the baseband complex channel phase and avoid frequency aliasing distortion caused by discrete sampling, the system must output dynamic geometric parameters continuously and at high frequency with extremely high time resolution.

[0004] However, the two main technical solutions currently relied upon for low-Earth orbit satellite orbit prediction and deviation compensation are both unable to simultaneously meet the requirements of high accuracy and high-frequency output: one is the analytical prediction method based on the two-line orbital elements (TLE), represented by the SGP4 model. This model can quickly solve for the target orbit through analytical formulas with extremely low computational overhead, and can meet the millisecond-level high-frequency output requirements of channel simulation. However, its inherent prediction accuracy is low, which can lead to severe distortion in channel phase calculation. The other is the orbit correction method based on numerical integration, such as orbit differential correction or joint spatial filtering. This type of method can significantly improve prediction accuracy by constructing high-dimensional nonlinear observation equations to achieve error correction in the three-dimensional domain. However, its computational complexity is high and convergence is slow, which can easily lead to calculation delays and computational bottlenecks when called continuously at high frequencies. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and system for compensating for time deviations in space target orbit prediction based on Doppler sequence matching. This method can effectively improve the accuracy of communication modeling for space targets such as satellites. It also features low computational overhead, high prediction accuracy, strong model stability, and is suitable for high-frequency real-time tracking and guidance requirements.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] Firstly, a method for compensating for time deviations in space target orbit prediction based on Doppler sequence matching is provided, comprising: acquiring the measured Doppler sequence of the space target within the visible arc of the station and a set of timestamps of the measured Doppler sequence; based on the double orbital elements of the space target and the set of timestamps of the measured Doppler sequence, obtaining the theoretical Doppler sequence corresponding to the station through the SGP4 orbit prediction model; aligning the theoretical Doppler sequence with the measured Doppler sequence using a time reference to obtain a theoretical Doppler sequence with an added time-domain shift; constructing a cost function model with the time-domain shift as the independent variable and the sum of squared residuals of the Doppler sequence as the optimization objective, and using an optimization algorithm to perform a global search on the cost function model to obtain the optimal time deviation; keeping the double orbital elements of the space target unchanged, compensating for the prediction time based on the optimal time deviation, using it to calculate the compensation time position, generating a preset step size query time sequence, batch solving and outputting continuous three-dimensional trajectories.

[0008] Furthermore, based on the double orbital elements of the space target and the timestamp set of the measured Doppler sequence, the theoretical Doppler sequence corresponding to the station is obtained through the SGP4 orbital prediction model. This includes: analyzing the double orbital elements of the space target using the SGP4 orbital prediction model to output the position and velocity vectors of the space target in the true equatorial vernal equinox inertial coordinate system; converting the position and velocity vectors of the space target in the true equatorial vernal equinox inertial coordinate system into the position and velocity vectors of the space target in the station's geocentric-geostatic coordinate system based on the coordinate system rotation transformation matrix; and calculating the theoretical Doppler sequence based on the position and velocity vectors of the space target in the station's geocentric-geostatic coordinate system, the expression of which is:

[0009] ;

[0010] ;

[0011] in, This is the timestamp for the theoretical prediction of the j-th sampling point; for The radial relative velocity at time t; and The space targets are respectively in The position vector and velocity vector in the geocentric and geofixed coordinate system at any given moment; This refers to the three-dimensional coordinate vector of the station in the geocentric fixed coordinate system. To theoretically predict Doppler frequency shift; The speed of light is constant; This refers to the carrier frequency of the measuring station equipment.

[0012] Furthermore, based on the piecewise cubic spline interpolation algorithm, the theoretical Doppler sequence and the measured Doppler sequence are aligned with a time reference to obtain a theoretical Doppler sequence with an added time-domain shift. The theoretical Doppler sequence with the added time-domain shift is then resampled and fitted, and the fitting expression is:

[0013] ;

[0014] in, The set time-domain shift amount; This is the timestamp of the i-th sampling point in the measured Doppler velocity sequence; For time-domain translation And resampling to time 1 Theoretical predicted radial velocity fitting value at the location; Forecast time set; This is the set of theoretically predicted radial velocities obtained by converting theoretically predicted Doppler sequences; This is a piecewise cubic spline interpolation function.

[0015] Furthermore, the cost function model, with the time-domain shift as the independent variable and the sum of squared residuals of the Doppler sequence as the optimization objective, is expressed as:

[0016] ;

[0017] in, The time-domain shift is The objective cost function value at time; N is the total number of timestamps of the measured sequence within the effective comparison arc; For the measured Doppler velocity sequence at time The corresponding measured radial velocity.

[0018] Furthermore, an optimization algorithm is used to perform a global search on the cost function model to obtain the optimal time deviation, specifically as follows:

[0019] ;

[0020] in, To obtain the optimal time deviation; The operator for solving the parameters represents the search interval for optimization in a given continuous time. Inside, searching for Reaching the global minimum , this Recorded as The global search employs a derivative-free one-dimensional continuous interval optimization algorithm.

[0021] Furthermore, the compensation time position is calculated as follows:

[0022] ;

[0023] in, The forecast time to be queried is entered by the user; The original number of double-track elements without any parameter modifications; This is the SGP4 orbit prediction solution function; The compensated three-dimensional position vector of the spatial target.

[0024] Furthermore, the three-dimensional trajectory is specifically as follows:

[0025] ;

[0026] ;

[0027] in, For constructing a continuous time series to be queried, This represents the start time with high temporal resolution. For high temporal resolution step size, To query the total number of steps in the sequence; To compensate for the continuous output of high temporal resolution three-dimensional position trajectory vector sequences.

[0028] Furthermore, a high-precision real-time scheduling mechanism based on hybrid sleep is adopted in the output control stage. Specifically, this includes: calculating the time difference between the theoretical trigger time of the current output frame and the current actual system time; if the time difference is greater than a preset time jitter threshold, a sleep function is called to release CPU resources to improve the system's clock scheduling granularity; if the time difference is less than or equal to the preset time jitter threshold, the thread remains active and enters a spin-lock loop. In the spin-lock state, the hardware clock is read until the actual time precisely reaches the theoretical trigger time, and the optimal time deviation is then substituted. Temporal compensation is performed, and the SGP4 orbit is solved by batch algebraic calculation, triggering the output of the three-dimensional trajectory data corresponding to the current frame.

[0029] Secondly, a space target orbit prediction time deviation compensation system based on Doppler sequence matching is provided, comprising: a data acquisition module for acquiring the measured Doppler sequence of the space target within the visible arc of the station and a set of timestamps of the measured Doppler sequence; a sequence construction module for acquiring the theoretical Doppler sequence corresponding to the station based on the double-row orbit elements of the space target and the set of timestamps of the measured Doppler sequence using the SGP4 orbit prediction model; a reference alignment module for aligning the theoretical Doppler sequence with the measured Doppler sequence using a time reference to obtain a theoretical Doppler sequence with an added time domain shift; an optimization solution module for constructing a cost function model with the time domain shift as the independent variable and the sum of squared residuals of the Doppler sequence as the optimization objective, and using an optimization algorithm to perform a global search on the cost function model to obtain the optimal time deviation; and a high-frequency compensation module for keeping the double-row orbit elements of the space target unchanged, compensating the prediction time based on the optimal time deviation, calculating the compensation time position, generating a preset step size query time sequence, batch solving and outputting continuous three-dimensional trajectories.

[0030] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0031] (1) This invention obtains the measured Doppler sequence of a space target within the visible arc of the station and the set of timestamps of the measured Doppler sequence; based on the double orbital elements of the space target and the set of timestamps of the measured Doppler sequence, the theoretical Doppler sequence corresponding to the station is obtained through the SGP4 orbit prediction model; the theoretical Doppler sequence is aligned with the measured Doppler sequence using a time reference to obtain a theoretical Doppler sequence with an added time-domain shift; a cost function model is constructed with the time-domain shift as the independent variable and the sum of squared residuals of the Doppler sequence as the optimization objective; and an optimization algorithm is used to optimize the cost function model. The model performs a global search to obtain the optimal time deviation; keeping the double-row orbit elements of the space target unchanged, it compensates the predicted time based on the optimal time deviation, which is used to calculate the position of the compensation time, generate a high-resolution query time series with a preset step size, and solve and output high-precision continuous three-dimensional trajectory in batches; it solves the technical problem of the difficulty in balancing high-precision correction, low computing power consumption and high-frequency real-time output in existing orbit prediction technology, and can effectively improve the accuracy of communication modeling of space targets such as satellites. At the same time, it has the characteristics of low computing overhead, high prediction accuracy and strong model stability, and is suitable for high-frequency real-time tracking and guidance requirements;

[0032] (2) The present invention adopts a non-intrusive time-domain translation compensation mechanism to optimize the error accumulation problem without changing the original orbit solution framework. Compared with the existing traditional methods that rely on high-dimensional matrix iteration and numerical integration, the present invention greatly reduces the amount of computation, significantly reduces the computing power overhead, and is compatible with lightweight hardware platforms.

[0033] (3) The present invention fully retains the inherent advantage of the analytical model having no integral overhead and can stably support high refresh rate trajectory output of 5 milliseconds or 10 milliseconds. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the main process of a space target orbit prediction time deviation compensation method based on Doppler sequence matching provided in an embodiment of the present invention;

[0035] Figure 2 This is a flowchart illustrating the high-precision real-time scheduling mechanism based on hybrid hibernation in an embodiment of the present invention;

[0036] Figure 3 This is a comparison chart of Doppler curve alignment and time deviation analysis in an embodiment of the present invention;

[0037] Figure 4 This is a comparison diagram of the three-dimensional spatial position error before and after time deviation compensation in an embodiment of the present invention;

[0038] Figure 5 This is a block diagram of a space target orbit prediction time deviation compensation system based on Doppler sequence matching provided in an embodiment of the present invention. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0040] Example 1

[0041] like Figure 1 As shown, a method for compensating for time deviations in space target orbit prediction based on Doppler sequence matching includes: acquiring the measured Doppler sequence of the space target within the visible arc of the station and a set of timestamps for the measured Doppler sequence; based on the double orbital elements of the space target and the set of timestamps for the measured Doppler sequence, obtaining the theoretical Doppler sequence corresponding to the station through the SGP4 orbit prediction model; aligning the theoretical Doppler sequence with the measured Doppler sequence using a time reference to obtain a theoretical Doppler sequence with an added time-domain shift; constructing a cost function model with the time-domain shift as the independent variable and the sum of squared residuals of the Doppler sequence as the optimization objective, and using an optimization algorithm to perform a global search on the cost function model to obtain the optimal time deviation; keeping the double orbital elements of the space target unchanged, compensating for the prediction time based on the optimal time deviation, using it to calculate the compensation time position, generating a high-resolution query time series with a preset step size, batch solving and outputting a high-precision continuous three-dimensional trajectory.

[0042] Step S1: Obtain the measured Doppler sequence of the space target within the visible arc segment of the station and the set of timestamps of the measured Doppler sequence.

[0043] Low-Earth orbit satellites travel at extremely high speeds, approximately 7.5 km / s, but the tracking window of telemetry and control equipment is extremely limited. Therefore, this invention strictly restricts the boundary constraints for data extraction, namely the "visible arc segment." Specifically, the geocentric-fixed coordinate system where the station is located is defined as the Northeast-Sky ENU coordinate system, and the elevation angle of the target in this coordinate system is... The effective observation occlusion threshold angle is set as follows: In this embodiment, 5° is preferred, and the time window within the visible arc segment is defined as... The following conditions must be met:

[0044] ;

[0045] in, For the target arrival time, The target's engagement time is determined. The measured radial velocity within this continuous time window is extracted and denoted as the measured Doppler velocity sequence. The corresponding timestamp set is , where N is the total number of timestamps of the measured sequence within the valid comparison arc.

[0046] Step S2: Based on the double orbital elements of the space target and the timestamp set of the measured Doppler sequence, obtain the theoretical Doppler sequence corresponding to the station through the SGP4 orbital prediction model.

[0047] S21. Analyze the TLE to output the current orbital motion state. First, obtain the satellite's current raw TLE. Analyze the TLE using the SGP4 orbital dynamics model and output the predicted discrete time series. Below, the satellite's position vector in the True Equator Mean Equinox inertial coordinate system (TEME). and velocity vector .

[0048] S22. Spatiotemporal Coordinate System Rotation Transformation. Since the station is located in a non-inertial coordinate system that rotates with the Earth, it is necessary to transform the satellite's TME coordinates to the Earth-Centered Earth-Fixed (ECEF) coordinate system. This involves introducing the Greenwich Mean Sidereal Time Transformation angle. Construct the Z-axis rotation matrix :

[0049] ;

[0050] ;

[0051] in, This is the Earth's rotational angular velocity vector. and These represent the target's position and velocity vectors in the ECEF coordinate system, respectively.

[0052] S23. Station Coordinate System Calculation. Given the geodetic coordinates of the station, convert them to absolute position vectors in the ECEF coordinate system. The details are as follows:

[0053] ;

[0054] ;

[0055] ;

[0056] Where L, B, and H are the latitude, longitude, and altitude of the geodetic coordinates. Let be the radius of curvature of the zonal circle, a be the semi-major axis of the Earth, and e be the first eccentricity of the Earth.

[0057] S24. Calculate the theoretically predicted radial velocity. Based on the satellite's ECEF state vector and the station's position vector, calculate the theoretical radial relative velocity. The mapping expression is as follows:

[0058] ;

[0059] According to the Doppler effect, the Doppler frequency shift and the target radial velocity satisfy a linear relationship:

[0060] ;

[0061] In the formula, This is to theoretically predict the discrete time of the j-th sampling point; for The radial relative velocity at time t; and The space targets are respectively in Position and velocity vectors at time ECEF; The three-dimensional coordinate vector of the station at ECEF; To theoretically predict Doppler frequency shift; The speed of light is constant; This refers to the carrier frequency of the measuring station equipment.

[0062] Step S3: Align the theoretical Doppler sequence with the measured Doppler sequence using a time reference to obtain a theoretical Doppler sequence with an added time-domain shift.

[0063] Because the sampling timestamp of the local hardware clock of the actual observation equipment is asynchronously misaligned with the discrete timestamp theoretically predicted by the SGP4 model, direct residual comparison is not possible. This invention employs a high-precision piecewise cubic spline interpolation algorithm to align the theoretical Doppler sequence with the measured Doppler sequence using a time reference, resulting in a theoretical Doppler sequence with an added time-domain shift. This theoretical Doppler sequence with the added time-domain shift is then subjected to high-precision resampling fitting, with the fitting expression being:

[0064] ;

[0065] in, The set time-domain shift amount; This is the timestamp of the i-th sampling point in the measured Doppler velocity sequence; For time-domain translation And resampling to time 1 Theoretical predicted radial velocity fitting value at the location; Forecast time set; This is the set of theoretically predicted radial velocities obtained by converting theoretically predicted Doppler sequences; This is a piecewise cubic spline interpolation function.

[0066] Step S4: Construct a cost function model with time-domain shift as the independent variable and the sum of squared residuals of the Doppler sequence as the optimization objective. Use an optimization algorithm to perform a global search on the cost function model to obtain the optimal time deviation.

[0067] S41. Construct a time-domain translation... The cost function, with a single independent variable, physically measures the global morphological difference between two radial velocity sequences aligned to a time reference across the entire visible arc. The cost function is defined as the sum of squared residuals:

[0068] ;

[0069] in, The time-domain shift is The objective cost function value at time; N is the total number of timestamps of the measured sequence within the effective comparison arc; For the measured Doppler velocity sequence at time The corresponding measured radial velocity.

[0070] S42. Set the continuous time optimization search interval. A global search is performed using a derivativeless one-dimensional continuous interval optimization algorithm based on the golden section method and parabolic interpolation to find the optimal time deviation that minimizes the cost function.

[0071] ;

[0072] in, To obtain the optimal time offset, The operator for solving the parameters represents the search interval for optimization in a given continuous time. Inside, searching for Reaching the global minimum , this Recorded as The global search employs a derivative-free one-dimensional continuous interval optimization algorithm to find the minimum point of the objective function.

[0073] Step S5: Keep the number of double-track elements of the space target unchanged, compensate the predicted time based on the optimal time deviation, calculate the position of the compensation time, generate a high-resolution query time sequence with a preset step size, solve in batches and output high-precision continuous three-dimensional trajectory.

[0074] S51. Based on the optimal time deviation compensation prediction time, the expression for calculating and outputting the three-dimensional position is as follows:

[0075] ;

[0076] in, The forecast time to be queried is entered by the user; The original number of double-track elements without any parameter modifications; This is the SGP4 orbit prediction solution function; The three-dimensional position vector of the space target after compensation.

[0077] S52. To meet the requirements of high-frequency dynamic tracking and guidance, generate a time resolution of... The continuous high-frequency time series to be queried is as follows:

[0078] ;

[0079] In the formula, For constructing a continuous time series to be queried; This represents the start time with high temporal resolution. For a high temporal resolution step size, the preferred high temporal resolution step size is... It takes 5ms or 10ms; To query the total number of steps in the sequence.

[0080] S53. To address the need for high temporal resolution tracking guidance, batch-substitute the SGP4 model and solve for the expression of the high temporal resolution 3D trajectory:

[0081] ;

[0082] In the formula, To utilize the algebraic analytical properties of SGP4 to continuously output high-temporal-resolution compensated 3D position trajectory vector sequences in batches, and One-to-one correspondence.

[0083] This invention introduces a high-precision real-time scheduling mechanism based on hybrid sleep in the output control stage. Such system jitter can directly lead to frame loss or misalignment of high-frequency boot data. In general non-real-time operating systems, the underlying thread scheduling mechanism is uncertain. Therefore, this invention employs a high-precision real-time scheduling mechanism based on hybrid sleep in the output control stage, such as... Figure 2 As shown.

[0084] The first step is to calculate the trigger time of the current output frame. = ;

[0085] The second step is to read the underlying high-precision hardware performance clock to obtain the current actual hardware time of the system. ;

[0086] The third step is comparison. and :

[0087] like ≥ It directly enters the trajectory calculation and output stage;

[0088] like < Calculate the remaining time and, based on a preset time jitter threshold (preferably 2ms), execute branch scheduling:

[0089] (a) If the remaining time is >2ms: call the system's underlying sleep function, force the system time scheduling granularity to be increased to 1ms, release CPU resources, enter the resource release sleep phase, and reacquire the current time after the sleep ends;

[0090] (b) If the remaining time is ≤2ms: immediately wake up the process and enter a spin-locked loop state, polling and waiting until the target trigger time is reached.

[0091] The fourth step is to ensure that the actual time precisely reaches the theoretical trigger time. When, substitute the optimal time deviation Temporal compensation is performed, and the SGP4 orbit is solved by batch algebraic calculation, immediately triggering the output of high-precision three-dimensional trajectory data corresponding to the current frame.

[0092] Once completed, proceed to the next frame scheduling loop and repeat steps one through four.

[0093] To further illustrate the technical effects of the Doppler sequence matching and time deviation compensation method described in this invention, the following detailed explanation is provided in conjunction with specific application scenario data and accompanying drawings.

[0094] In practical low-Earth orbit satellite scenarios, since it is impossible to directly obtain the absolute true trajectory of the target, this invention uses the HPOP module in the internationally recognized high-precision numerical orbit propagator STK software. This module integrates a 70×70 order Earth's true gravity field, a Jacchia-Roberts upper atmosphere density model, and a three-body gravity model, generating high-fidelity simulated observation data as an equivalent measured true value benchmark. The station carrier frequency is 10 GHz, and the speed of light... ≈2.99792×10 8 m / s. Simultaneously, using the publicly available twin orbit elements (TLE) of low-Earth orbit satellites as initial input, theoretical forecast data is generated through the C++ SGP4 forecast engine constructed in this invention.

[0095] like Figure 3 The diagram shown is a comparison of Doppler curve alignment and time deviation optimization in this invention.

[0096] Depend on Figure 3 It is evident that, before compensation (red dashed line in the figure), the along-track hysteresis effect caused by atmospheric drag at low orbit results in a significant time misalignment between the theoretical Doppler curve predicted by the traditional SGP4 and the measured true curve (black solid line in the figure) at key geometric features such as the closest approach point.

[0097] After employing the fully visible arc segment matching and continuous interval optimization algorithm described in steps S3 and S4 of this invention, the cost function obtains a global minimum, and the globally optimal time deviation of the satellite in the current arc segment is accurately calculated. ≈3.09 seconds. After applying this time-domain compensation, the corrected predicted Doppler curve (green dotted line in the figure) highly overlaps with the measured true curve, achieving perfect alignment of heterogeneous asynchronous signals in the time domain.

[0098] like Figure 4 The diagram shown is a comparison of the satellite's three-dimensional position error before and after time deviation compensation in this invention.

[0099] Depend on Figure 4 It is evident that the uncompensated original SGP4 model (red dashed curve) accumulates a 3D spatial position error of over 16 kilometers within a short period of extrapolation, completely failing to meet guidance requirements. However, by keeping the original TLE unchanged and only subtracting the aforementioned error from the input... After compensation of the time series, the output 10ms high-frequency three-dimensional spatial position (green solid curve) has an absolute spatial error that drops from 16 kilometers to less than 7 kilometers instantly.

[0100] By statistically analyzing the error across the entire arc segment, the method described in this invention reduces the average three-dimensional prediction error by more than 58%. This invention, while maintaining the SGP4 model without numerical integration overhead and without compromising the dynamic stability of the analytical model, significantly eliminates the massive spatial error dominated by along-track hysteresis simply through a one-dimensional time scalar translation. This technological breakthrough greatly improves the success rate and reliability of low-computing-power edge computing devices in capturing low-Earth orbit space debris.

[0101] Example 2

[0102] Based on the space target orbit prediction time deviation compensation method based on Doppler sequence matching described in Embodiment 1, this embodiment provides a space target orbit prediction time deviation compensation system based on Doppler sequence matching, such as... Figure 5 As shown, it includes:

[0103] The data acquisition module is used to acquire the measured Doppler sequence of the space target within the visible arc of the station and the set of timestamps of the measured Doppler sequence;

[0104] The sequence construction module is used to obtain the theoretical Doppler sequence corresponding to the station based on the double-track orbital elements of the space target and the timestamp set of the measured Doppler sequence through the SGP4 orbital prediction model.

[0105] The reference alignment module is used to align the theoretical Doppler sequence with the measured Doppler sequence using a time reference, thereby obtaining a theoretical Doppler sequence with an added time-domain shift.

[0106] The optimization module is used to construct a cost function model with time-domain shift as the independent variable and the sum of squared residuals of the Doppler sequence as the optimization objective. The optimization algorithm is used to perform a global search on the cost function model to obtain the optimal time deviation.

[0107] The high-frequency compensation module is used to keep the number of the two-track elements of the space target unchanged. Based on the optimal time deviation compensation prediction time, it is used to calculate the position of the compensation time, generate a high-resolution query time sequence with a preset step size, and solve and output high-precision continuous three-dimensional trajectory in batches.

[0108] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0109] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0110] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0111] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0112] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A method for compensating for time deviations in space target orbit prediction based on Doppler sequence matching, characterized in that, include: Obtain the measured Doppler sequence of the space target within the visible arc of the station and the set of timestamps of the measured Doppler sequence; Based on the double orbital elements of the space target and the timestamp set of the measured Doppler sequence, the theoretical Doppler sequence corresponding to the station is obtained through the SGP4 orbital prediction model; The theoretical Doppler sequence and the measured Doppler sequence are aligned with a time reference to obtain a theoretical Doppler sequence with an added time-domain shift. A cost function model is constructed with time-domain shift as the independent variable and the sum of squared residuals of the Doppler sequence as the optimization objective. The optimal time deviation is obtained by performing a global search on the cost function model using an optimization algorithm. Keeping the number of double-track elements of the space target unchanged, the predicted time is compensated based on the optimal time deviation, which is used to calculate the position of the compensation time, generate a preset step size query time sequence, solve in batches and output continuous three-dimensional trajectory.

2. The method for compensating for time deviations in space target orbit prediction based on Doppler sequence matching according to claim 1, characterized in that, Based on the double orbital elements of the space target and the timestamp set of the measured Doppler sequence, the theoretical Doppler sequence corresponding to the station is obtained through the SGP4 orbit prediction model, including: The SGP4 orbit prediction model is used to analyze the double orbital elements of a space target, and the position and velocity vectors of the space target in the true equatorial vernal equinox inertial coordinate system are output. Based on the coordinate system rotation transformation matrix, the position and velocity vectors of the space target in the true equatorial vernal equinox inertial coordinate system are converted into the position and velocity vectors of the space target in the station's geocentric and geofixed coordinate system; Based on the Doppler effect, the theoretical Doppler sequence is calculated using the position and velocity vectors of the space target in the geocentric-ground-fixed coordinate system of the station. Its expression is as follows: ； ； in, This is the timestamp for the theoretical prediction of the j-th sampling point; for The radial relative velocity at time t; and The space targets are respectively in The position vector and velocity vector in the geocentric and geofixed coordinate system at any given moment; This represents the three-dimensional coordinate vector of the station in the Earth-centered Earth-fixed coordinate system. To theoretically predict Doppler frequency shift; The speed of light is constant; This refers to the carrier frequency of the measuring station equipment.

3. The method for compensating for time deviations in space target orbit prediction based on Doppler sequence matching according to claim 2, characterized in that, The theoretical Doppler sequence and the measured Doppler sequence are time-referenced using a piecewise cubic spline interpolation algorithm to obtain a theoretical Doppler sequence with an added time-domain shift. The theoretical Doppler sequence with the added time-domain shift is then resampled and fitted, and the fitting expression is: ； in, The set time-domain shift amount; The timestamp of the i-th sampling point in the measured Doppler sequence; For time-domain translation And resampling to time 1 Theoretical predicted radial velocity fitting value at the location; Forecast time set; This is the set of theoretically predicted radial velocities obtained by converting theoretically predicted Doppler sequences; This is a piecewise cubic spline interpolation function.

4. The method for compensating for time deviations in space target orbit prediction based on Doppler sequence matching according to claim 3, characterized in that, The cost function model, with the time-domain shift as the independent variable and the sum of squared Doppler sequence residuals as the optimization objective, is expressed as: ； in, The time-domain shift is The objective cost function value at time; N is the total number of timestamps of the measured sequence within the effective comparison arc; To measure the Doppler sequence at time 10:00 The corresponding measured radial velocity.

5. The method for compensating for time deviations in space target orbit prediction based on Doppler sequence matching according to claim 4, characterized in that, The optimal time bias is obtained by performing a global search on the cost function model using an optimization algorithm, specifically as follows: ； in, To obtain the optimal time deviation; The operator for solving the parameters represents the search interval for optimization in a given continuous time. Inside, searching for Reaching the global minimum , this Recorded as The global search employs a derivative-free one-dimensional continuous interval optimization algorithm.

6. The method for compensating for time deviations in space target orbit prediction based on Doppler sequence matching according to claim 5, characterized in that, The calculation of the compensation time position is as follows: ； in, The forecast time to be queried is entered by the user; The original number of double-track elements without any parameter modifications; This is the SGP4 orbit prediction solution function; The compensated three-dimensional position vector of the spatial target.

7. The method for compensating for time deviations in space target orbit prediction based on Doppler sequence matching according to claim 6, characterized in that, The three-dimensional trajectory is specifically as follows: ； ； in, For constructing a continuous time series to be queried, This represents the start time with high temporal resolution. For high temporal resolution step size, To query the total number of steps in the sequence; To compensate for the continuous output of high temporal resolution three-dimensional position trajectory vector sequences.

8. The method for compensating for time deviations in space target orbit prediction based on Doppler sequence matching according to claim 7, characterized in that, The output control stage employs a high-precision real-time scheduling mechanism based on hybrid sleep mode, specifically including: Calculate the time difference between the theoretical trigger time of the current output frame and the current actual time of the system; If the time difference is greater than the preset time jitter threshold, the sleep function is called to release CPU resources in order to improve the clock scheduling granularity of the system. If the time difference is less than or equal to a preset time jitter threshold, the thread remains active and enters a spin-locked loop. In the spin-locked state, the hardware clock is read until the actual time precisely reaches the theoretical trigger time, and the optimal time deviation is then applied. Temporal compensation is performed, and the SGP4 orbit is solved by batch algebraic calculation, triggering the output of the three-dimensional trajectory data corresponding to the current frame.

9. A space target orbit prediction time deviation compensation system based on Doppler sequence matching, characterized in that, include: The data acquisition module is used to acquire the measured Doppler sequence of the space target within the visible arc of the station and the set of timestamps of the measured Doppler sequence; The sequence construction module is used to obtain the theoretical Doppler sequence corresponding to the station based on the double-track orbital elements of the space target and the timestamp set of the measured Doppler sequence through the SGP4 orbital prediction model. The reference alignment module is used to align the theoretical Doppler sequence with the measured Doppler sequence using a time reference, thereby obtaining a theoretical Doppler sequence with an added time-domain shift. The optimization module is used to construct a cost function model with time-domain shift as the independent variable and the sum of squared residuals of the Doppler sequence as the optimization objective. The optimization algorithm is used to perform a global search on the cost function model to obtain the optimal time deviation. The high-frequency compensation module is used to keep the number of double orbital elements of the space target unchanged. Based on the optimal time deviation compensation prediction time, it is used to calculate the compensation time position, generate a preset step size query time sequence, solve in batches and output continuous three-dimensional trajectory.

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