Calculation method for determining satellite azimuth pitching through TLE data

Abstract

The invention discloses a calculation method for determining satellite azimuth pitching through TLE data, relates to the technical field of satellite azimuth pitching calculation, and remarkably improves the cooperation precision of satellite azimuth pitching angle calculation by dynamically calibrating the local UTC time of multiple ground stations. In scenes of satellite measurement and control, deep space exploration, emergency communication and the like, according to a traditional method, due to clock asynchronism, calculation results of all stations are inconsistent, and beam pointing or relay tracking continuity of an antenna array is affected; according to the method, the satellite position deviation is creatively utilized to reversely deduce the time error, the space deviation is mapped into the time calibration amount, the time reference is directly unified from the data level, and high-cost deployment depending on external clock synchronization equipment is avoided.

Description

Technical Field

[0001] This invention relates to the field of satellite elevation and azimuth calculation technology, and in particular to a calculation method for determining satellite azimuth and elevation using TLE data. Background Technology

[0002] In the fields of satellite telemetry, tracking, and command (TT&C), deep space exploration, and emergency communications, multiple widely distributed ground stations need to coordinate to track the same satellite in order to achieve continuous coverage or improve positioning accuracy. Such scenarios rely on unified satellite azimuth and elevation calculation results to guide antenna pointing. The current mainstream solution analyzes TLE data, uses the SGP4 orbit model to calculate the satellite position, and then converts it into azimuth / elevation angles in the local coordinate system of each station, and outputs the results synchronously with UTC timestamps. This process meets the basic requirements when running independently at a single station, but faces a core bottleneck when extended to multi-station collaborative scenarios.

[0003] Multi-station collaboration requires all stations to calculate satellite positions based on strictly consistent UTC time. However, the accuracy of each station's local clock is limited by the NTP protocol (typical error ±100ms), and network latency further disrupts time synchronization. For high-speed low-orbit satellites (speed >7km / s), time deviations will directly translate into position calculation errors. For example, a 100ms time difference can cause a satellite position shift of over 700 meters, resulting in an azimuth difference of over 0.5° during close-range tracking. Although existing solutions correct positions through post-event data alignment, the real-time calculation process cannot eliminate the time inconsistencies in the original outputs of each station, leading to beam divergence of the collaborative antenna array or interruption of relay tracking.

[0004] Some newer collaborative systems use the PTP precision clock protocol to compress the time error between stations to within ±1ms; however, the deployment cost is high and it cannot eliminate the accumulated error in the satellite position calculation process; some other schemes have each station independently output the raw azimuth / elevation angle and UTC time, and the central node fuses the data through Kalman filtering; this scheme introduces communication delay, limits real-time performance, and depends on the accuracy of the filtering model. Summary of the Invention

[0005] In view of the aforementioned existing problems, the present invention is proposed.

[0006] This invention provides a calculation method for determining satellite azimuth and elevation using TLE data to solve the problem of inconsistent azimuth and elevation calculations caused by time synchronization errors when multiple ground stations are collaboratively tracking satellites, and the fact that existing measures cannot fundamentally eliminate asynchronous deviations.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] This invention provides a method for calculating satellite azimuth and elevation using TLE data, comprising:

[0009] Step S1: Parse the TLE data and obtain the satellite orbital parameters;

[0010] Step S2: Based on the orbital parameters, calculate the satellite's geocentric coordinate system position at a preset UTC time using the SGP4 model;

[0011] Step S3: Convert the geocentric coordinate system position into azimuth and elevation angles in the local coordinate system of the ground station;

[0012] Step S4: Output the converted azimuth angle, elevation angle, and corresponding UTC timestamp;

[0013] Step S5: The first ground station broadcasts its calculated satellite position and corresponding first UTC time;

[0014] Step S6: The second ground station receives the satellite position and the first UTC time, and reverse-calculates the theoretical position of the satellite in the local coordinate system of the second ground station under the first UTC time;

[0015] Step S7: Based on the deviation between the theoretical position and the satellite position calculated in real time by the second ground station, dynamically calibrate the local UTC time of the second ground station.

[0016] As a preferred embodiment of the calculation method for determining satellite azimuth and elevation using TLE data described in this invention, the dynamic calibration in step S7 specifically includes:

[0017] Calculate the magnitude of the position deviation vector;

[0018] The time error value is obtained by dividing the satellite's instantaneous velocity scalar by the aforementioned modulus.

[0019] The time error value is added to the local UTC time of the second ground station;

[0020] In the dynamic calibration of step S7, the steps for calculating the time error value include:

[0021] Based on the position deviation vector output in step S6 and the satellite instantaneous velocity vector obtained in step S2, the validity of the velocity scalar is checked. When the velocity scalar exceeds a preset threshold, the magnitude of the position deviation vector is calculated, and the time error value is obtained by division. Otherwise, the time error is maintained at zero. The specific calculation formula includes:

[0022] ,

[0023] ,

[0024] ,

[0025] in, This represents the satellite's instantaneous velocity vector, in m / s. express The scalar modulus, in m / s. This represents the position deviation vector, in meters (m). The x-axis component of the position deviation vector, in meters (m). The y-axis component of the position deviation vector, in meters (m). The z-axis component of the position deviation vector, in meters. The magnitude of the position deviation vector, in meters (m). This indicates the preset minimum speed threshold, in m / s. This represents the time error value, in seconds (s).

[0026] After the calculation is completed, It is used directly to overlay and adjust the local UTC time of the second ground station.

[0027] As a preferred embodiment of the calculation method for determining satellite azimuth and elevation using TLE data described in this invention, the calculation of the time error value satisfies the following constraints:

[0028] Scalar division is used only when the angle between the satellite velocity vector and the position deviation vector is less than a preset threshold.

[0029] Otherwise, the time error value is calculated using the projection component of the position deviation vector in the direction of satellite velocity;

[0030] In step S7, during the calculation of the time error value of the projection component under constraints, that is, when the satellite velocity vector... With position deviation vector The included angle At that time, the time error value is calculated through the projected components. :

[0031] Calculate the unit vector in the velocity direction, then project the position deviation onto this direction to obtain the pure distance deviation component. Finally, divide the projected component by the velocity scalar to obtain the time error; the specific calculation formula is as follows:

[0032] ,

[0033] ,

[0034] ,

[0035] in, This represents the satellite's instantaneous velocity vector, in m / s. The scalar magnitude of the velocity vector, expressed in m / s. A unit vector representing the direction of velocity, dimensionless. This represents the position deviation vector, in meters (m). This represents the vector dot product operator. This represents the projected component of the position deviation in the velocity direction, in meters (m). Specifically refers to the satellite velocity vector direction, This represents the time error value, in seconds (s).

[0036] This calculation is only performed when... Activated at time From the dot product formula Sure, Represents the cosine value of the included angle;

[0037] like If a minimum speed threshold is preset, then a forced setting will be implemented. .

[0038] As a preferred embodiment of the calculation method for determining satellite azimuth and elevation using TLE data described in this invention, the instantaneous velocity of the satellite in step S2 is obtained as follows:

[0039] The satellite's velocity vector in the geocentric coordinate system is output synchronously using the SGP4 model.

[0040] In a preferred embodiment of the calculation method for determining satellite azimuth and elevation using TLE data as described in this invention, the broadcast in step S4 is implemented using any of the following protocols:

[0041] A dedicated measurement and control network based on TCP / IP;

[0042] Low-latency satellite communication links.

[0043] As a preferred embodiment of the calculation method for determining satellite azimuth and elevation using TLE data described in this invention, step S6, the back-calculation operation, includes:

[0044] The satellite position broadcast by the first ground station is transformed from the geocentric coordinate system to the local coordinate system of the second ground station;

[0045] The transformed position is taken as the theoretical position.

[0046] As a preferred embodiment of the calculation method for determining satellite azimuth and elevation using TLE data as described in this invention, the final output UTC timestamp is the calibrated local UTC time.

[0047] As a preferred embodiment of the calculation method for determining satellite azimuth and elevation using TLE data as described in this invention, the broadcast satellite position data format includes three-dimensional coordinate values ​​in a geocentric coordinate system and the corresponding first UTC timestamp, and is encapsulated in JSON or binary protocol.

[0048] As a preferred embodiment of the calculation method for determining satellite azimuth and elevation using TLE data as described in this invention, the transformation from the geocentric coordinate system to the local coordinate system adopts a transformation matrix from the geocentric geodetic coordinate system ECEF to the station-centric coordinate system ENU, and the transformation parameters include the geodetic latitude, longitude and elevation of the ground station.

[0049] As a preferred embodiment of the calculation method for determining satellite azimuth and elevation using TLE data as described in this invention, the preset threshold is that the angle between the satellite velocity vector and the position deviation vector is less than 30 degrees.

[0050] The beneficial effects of this invention are as follows: By dynamically calibrating the local UTC time of multiple ground stations, this invention significantly improves the collaborative accuracy of satellite azimuth and elevation angle calculations. In scenarios such as satellite telemetry and control, deep space exploration, and emergency communications, traditional methods suffer from inconsistent calculation results at different stations due to clock asynchrony, affecting the beam pointing of antenna arrays or the continuity of relay tracking. This invention innovatively utilizes satellite position deviations to infer time errors, mapping spatial offsets into time calibration quantities, directly unifying the time reference at the data level, and avoiding the high-cost deployment of external clock synchronization equipment.

[0051] Specifically, the first ground station broadcasts its calculated satellite position and UTC time. The second ground station then uses this information to deduce the theoretical position in its local coordinate system and compares it with the real-time results to generate a position deviation vector. Based on the satellite's motion characteristics, this deviation primarily stems from time asynchrony. The local UTC time is dynamically calibrated using the geometric relationship between the velocity vector and the deviation vector (scalar division or projection component calculation). This mechanism ensures that the azimuth and elevation angles output by each station remain consistent, even in highly dynamic orbits, reducing the risk of tracking interruptions.

[0052] This invention is compatible with existing SGP4 models and TLE data streams, adding only lightweight vector operations with minimal impact on real-time performance. Simultaneously, computational efficiency is optimized through preset thresholds (such as minimum velocity and a 30-degree angle constraint), avoiding invalid calibrations. Standardized coordinate transformation and data encapsulation (such as the ECEF-ENU matrix and JSON protocol) enhance system compatibility and facilitate integration into multi-station collaborative networks. In practical applications, it can improve the reliability of low-Earth orbit satellite transit tracking, especially suitable for complex scenarios such as polar regions or maneuvering satellites. Attached Figure Description

[0053] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a flowchart of a calculation method for determining satellite azimuth and elevation using TLE data in Example 1. Detailed Implementation

[0055] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0056] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0057] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0058] Example 1, referring to Figure 1 This embodiment provides a calculation method for determining satellite azimuth and elevation using TLE data, including the following steps:

[0059] Step S1: Parse the TLE data and obtain the satellite orbital parameters;

[0060] Step S2: Based on the orbital parameters, calculate the satellite's geocentric coordinate system position at the preset UTC time using the SGP4 model;

[0061] The instantaneous velocity of the satellite in step S2 is obtained as follows:

[0062] The satellite's velocity vector in the geocentric coordinate system is output synchronously using the SGP4 model;

[0063] Step S3: Convert the position in the geocentric coordinate system to the azimuth and elevation angles in the local coordinate system of the ground station;

[0064] Step S4: Output the converted azimuth angle, elevation angle, and corresponding UTC timestamp;

[0065] The broadcast in step S4 is implemented using any of the following protocols:

[0066] A dedicated measurement and control network based on TCP / IP;

[0067] Low-latency satellite communication links;

[0068] Step S5: The first ground station broadcasts its calculated satellite position and corresponding first UTC time;

[0069] Step S6: The second ground station receives the satellite position and the first UTC time, and then calculates the theoretical position of the satellite in the local coordinate system of the second ground station under the first UTC time.

[0070] The reverse calculation operation in step S6 includes:

[0071] The satellite position broadcast by the first ground station is transformed from the geocentric coordinate system to the local coordinate system of the second ground station;

[0072] The transformed position is used as the theoretical position;

[0073] The transformation from the geocentric coordinate system to the local coordinate system uses the transformation matrix from the geocentric geodetic coordinate system ECEF to the station-centric coordinate system ENU. The transformation parameters include the geodetic latitude, longitude and elevation of the ground station.

[0074] Step S7: Dynamically calibrate the local UTC time of the second ground station based on the deviation between the theoretical position and the satellite position calculated in real time by the second ground station;

[0075] The dynamic calibration in step S7 specifically includes:

[0076] Calculate the magnitude of the position deviation vector;

[0077] The time error value is obtained by dividing the satellite's instantaneous velocity scalar by the modulus.

[0078] Add the time error value to the local UTC time of the second ground station;

[0079] In the dynamic calibration of step S7, the steps for calculating the time error value include:

[0080] Based on the position deviation vector output in step S6 and the satellite instantaneous velocity vector obtained in step S2, the validity of the velocity scalar is checked. When the velocity scalar exceeds a preset threshold, the magnitude of the position deviation vector is calculated, and the time error value is obtained by division. Otherwise, the time error is kept at zero to avoid calculation failure. The specific calculation formula includes:

[0081] ,

[0082] ,

[0083] ,

[0084] in, This represents the satellite's instantaneous velocity vector, in m / s. express The scalar modulus, in m / s. This represents the position deviation vector, in meters (m). The x-axis component of the position deviation vector, in meters (m). The y-axis component of the position deviation vector, in meters (m). The z-axis component of the position deviation vector, in meters. The magnitude of the position deviation vector, in meters (m). This indicates the preset minimum speed threshold, in m / s. This represents the time error value, in seconds (s).

[0085] After the calculation is completed, It is directly used to overlay and adjust the local UTC time of the second ground station, forming a closed-loop process of data detection → modulus calculation → division calibration;

[0086] Specifically, this method converts positional deviation into time error, utilizing the satellite's motion geometry to address the issue of asynchronous time across multiple stations. By dynamically mapping spatial offsets to time differences, the calibration process becomes more direct and efficient, reducing antenna pointing deviations and significantly improving the tracking continuity, especially for high-speed, low-Earth orbit satellites. The calculations are based on existing data streams, without adding extra overhead, and boundary condition handling enhances system robustness and avoids invalid computations. After calibration, the time references of multiple stations are unified, improving the coordinated accuracy of azimuth and elevation angles, making it suitable for demanding scenarios such as emergency communications.

[0087] The calculation of the time error value satisfies the following constraints:

[0088] Scalar division is used only when the angle between the satellite velocity vector and the position deviation vector is less than a preset threshold.

[0089] Otherwise, the time error value is calculated using the projection component of the position deviation vector in the direction of satellite velocity;

[0090] In step S7, during the calculation of the time error value of the projection component under constraints, that is, when the satellite velocity vector... With position deviation vector The included angle At that time, the time error value is calculated through the projected components. :

[0091] Calculate the unit vector in the velocity direction, then project the position deviation onto this direction to obtain the pure distance deviation component. Finally, divide the projected component by the velocity scalar to obtain the time error; the specific calculation formula is as follows:

[0092] ,

[0093] ,

[0094] ,

[0095] in, This represents the satellite's instantaneous velocity vector, in m / s. The scalar magnitude of the velocity vector, expressed in m / s. A unit vector representing the direction of velocity, dimensionless. This represents the position deviation vector, in units of meters (m). The output unit depends on the input vector unit. The input is m, when Input is , This represents the vector dot product operator. This represents the projected component of the position deviation in the velocity direction, in meters (m). Specifically refers to the satellite velocity vector direction, This represents the time error value, in seconds (s).

[0096] This calculation is only performed when... Activated at time From the dot product formula Sure, Represents the cosine value of the included angle;

[0097] Forming a closed loop of orientation detection → projection decomposition → scalar division;

[0098] like If a minimum speed threshold is preset, then a forced setting will be implemented. ;

[0099] Specifically, when there is a large angular deviation between the position deviation and the velocity direction, projection calculation can eliminate the interference of the vertical component, so that the time error only reflects the true offset along the trajectory direction. This solves the problem of calibration failure caused by non-collinear motion due to satellite maneuvers or perturbations, and avoids incorrect antenna pointing correction. The method is based on the principle of vector algebra, the computational load is controllable, and it forms a complementary logic with scalar division, covering all motion scenarios. Actual deployment shows that during low-Earth orbit satellite orbit changes, the azimuth consistency is significantly improved, especially for complex orbits such as polar transits.

[0100] The preset threshold is that the angle between the satellite velocity vector and the position deviation vector is less than 30 degrees;

[0101] The final output UTC timestamp is the calibrated local UTC time;

[0102] The broadcast satellite position data format includes three-dimensional coordinates in the geocentric coordinate system and the corresponding first UTC timestamp, and is encapsulated in JSON or binary protocol.

[0103] This embodiment provides a method for determining satellite azimuth and elevation using TLE data. Addressing the inconsistency in azimuth and elevation calculations caused by time synchronization errors in multi-ground station collaborative tracking scenarios, a dynamic calibration mechanism is proposed. The scheme is based on the standard SGP4 orbit model and achieves unified time reference across multiple stations through innovative algorithm design, requiring no hardware modifications and combining theoretical rigor with engineering practicality.

[0104] The technical solution framework includes:

[0105] 1. Data parsing and location calculation

[0106] Parse TLE data to obtain satellite orbital parameters (step S1), and use the SGP4 model to calculate the geocentric coordinate system position and velocity vector at the preset UTC time (step S2). The position transformation module converts the geocentric coordinates into the azimuth and elevation angles of each station's local coordinate system (step S3), and outputs the initial results and UTC timestamp (step S4).

[0107] 2. Cross-site collaborative calibration core

[0108] The first ground station broadcasts its calculated satellite position and first UTC time (step S5); after receiving this, the second ground station uses coordinate transformation to deduce the theoretical position in its local coordinate system (step S6). The key innovation lies in the dynamic calibration mechanism (step S7):

[0109] Generate a deviation vector by comparing the theoretical position with the real-time position;

[0110] Based on the geometric relationship between satellite velocity and deviation vector, the time error value is calculated:

[0111] When the angle between the speed and the deviation is less than 30°, scalar division is used;

[0112] When the included angle is ≥30°, vertical interference is eliminated by projection components;

[0113] The time error value is superimposed onto the local UTC time to achieve real-time calibration.

[0114] 3. Supporting technology integration

[0115] Data transmission uses lightweight encapsulation (JSON / binary protocol) and is compatible with TCP / IP or satellite links (weight 8).

[0116] The coordinate transformation is based on the standard ECEF-ENU rotation matrix, with parameters including geodetic latitude and longitude and elevation (weight 9).

[0117] The output uses a calibrated UTC timestamp (weight 7) to ensure consistency of results across multiple stations.

[0118] In summary, this invention addresses the problem of traditional methods relying on external clock synchronization or post-processing filtering. This solution maps position deviation to time error at the algorithm level, directly eliminating computational bias caused by insufficient NTP accuracy. The calibration process embeds a real-time computation stream, avoiding communication delays, making it particularly suitable for cooperative tracking of high-speed satellites (>7km / s).

[0119] Furthermore, it automatically switches between scalar division and projection calculations using an included angle threshold (30°), covering both linear motion and maneuvering trajectory changes.

[0120] Scalar division optimizes computational efficiency under collinear motion;

[0121] The projected component eliminates non-radial deviations caused by perturbation, preventing incorrect antenna pointing correction.

[0122] In terms of industrial compatibility and ease of deployment:

[0123] Fully compatible with SGP4 / TLE standard workflows, and seamlessly integrated with open-source software such as gpredict;

[0124] Lightweight vector operations (module, dot product) have low computational requirements and can be performed by ordinary embedded devices;

[0125] The data interface is standardized (JSON encapsulation of weight 8) to support heterogeneous ground station networking.

[0126] The system's robustness has been enhanced, and boundary condition handling has been improved.

[0127] Speed ​​threshold prevents division by zero failure;

[0128] Angle constraints prevent invalid calibration in low-correlation scenarios;

[0129] Coordinate transformation parameters are bound to the geodetic datum in a closed loop to eliminate the propagation of geographical errors.

[0130] This solution can be widely applied in multi-station collaborative scenarios such as satellite tracking and control networks, low-Earth orbit constellation monitoring, and deep space exploration, significantly improving the beam pointing consistency of antenna arrays and reducing the risk of tracking interruptions. Its pure algorithm upgrade feature provides existing ground station systems with a low-cost, high-efficiency accuracy optimization path, and has outstanding value for tasks such as emergency communication and space target surveillance.

[0131] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A calculation method for determining satellite azimuth and elevation using TLE data, characterized in that, include, Step S1: Parse the TLE data and obtain the satellite orbital parameters; Step S2: Based on the orbital parameters, calculate the satellite's geocentric coordinate system position at a preset UTC time using the SGP4 model; Step S3: Convert the geocentric coordinate system position into azimuth and elevation angles in the local coordinate system of the ground station; Step S4: Output the converted azimuth angle, elevation angle, and corresponding UTC timestamp; Step S5: The first ground station broadcasts its calculated satellite position and corresponding first UTC time; Step S6: The second ground station receives the satellite position and the first UTC time, and reverse-calculates the theoretical position of the satellite in the local coordinate system of the second ground station under the first UTC time; Step S7: Based on the deviation between the theoretical position and the satellite position calculated in real time by the second ground station, dynamically calibrate the local UTC time of the second ground station.

2. The calculation method for determining satellite azimuth and elevation using TLE data as described in claim 1, characterized in that, The dynamic calibration in step S7 specifically includes: Calculate the magnitude of the position deviation vector; The time error value is obtained by dividing the satellite's instantaneous velocity scalar by the aforementioned modulus. The time error value is added to the local UTC time of the second ground station; In the dynamic calibration of step S7, the steps for calculating the time error value include: Based on the position deviation vector output in step S6 and the satellite instantaneous velocity vector obtained in step S2, the validity of the velocity scalar is checked. When the velocity scalar exceeds a preset threshold, the magnitude of the position deviation vector is calculated, and the time error value is obtained by division. Otherwise, the time error is maintained at zero. The specific calculation formula includes: ， ， ， in, This represents the satellite's instantaneous velocity vector, in m / s. express The scalar modulus, in m / s. This represents the position deviation vector, in meters (m). The x-axis component of the position deviation vector, in meters (m). The y-axis component of the position deviation vector, in meters (m). The z-axis component of the position deviation vector, in meters. The magnitude of the position deviation vector, in meters (m). This indicates the preset minimum speed threshold, in m / s. This represents the time error value, in seconds (s). After the calculation is completed, It is used directly to overlay and adjust the local UTC time of the second ground station.

3. The calculation method for determining satellite azimuth and elevation using TLE data as described in claim 2, characterized in that, The calculation of the time error value satisfies the following constraints: Scalar division is used only when the angle between the satellite velocity vector and the position deviation vector is less than a preset threshold. Otherwise, the time error value is calculated using the projection component of the position deviation vector in the direction of satellite velocity; In step S7, during the calculation of the time error value of the projection component under constraints, that is, when the satellite velocity vector... With position deviation vector The included angle At that time, the time error value is calculated through the projected components. : Calculate the unit vector in the velocity direction, then project the position deviation onto this direction to obtain the pure distance deviation component. Finally, divide the projected component by the velocity scalar to obtain the time error; the specific calculation formula is as follows: ， ， ， in, This represents the satellite's instantaneous velocity vector, in m / s. The scalar magnitude of the velocity vector, expressed in m / s. A unit vector representing the direction of velocity, dimensionless. This represents the position deviation vector, in meters (m). This represents the vector dot product operator. This represents the projected component of the position deviation in the velocity direction, in meters (m). Specifically refers to the satellite velocity vector direction, This represents the time error value, in seconds (s). This calculation is only performed when... Activated at time From the dot product formula Sure, Represents the cosine value of the included angle; like If a minimum speed threshold is preset, then a forced setting will be implemented. .

4. The calculation method for determining satellite azimuth and elevation using TLE data as described in claim 1, characterized in that, The instantaneous velocity of the satellite in step S2 is obtained as follows: The satellite's velocity vector in the geocentric coordinate system is output synchronously using the SGP4 model.

5. The calculation method for determining satellite azimuth and elevation using TLE data as described in claim 1, characterized in that, The broadcast in step S4 is implemented using any of the following protocols: A dedicated measurement and control network based on TCP / IP; Low-latency satellite communication links.

6. The calculation method for determining satellite azimuth and elevation using TLE data as described in claim 1, characterized in that, The reverse calculation operation in step S6 includes: The satellite position broadcast by the first ground station is transformed from the geocentric coordinate system to the local coordinate system of the second ground station; The transformed position is taken as the theoretical position.

7. The calculation method for determining satellite azimuth and elevation using TLE data as described in claim 1, characterized in that, The final output UTC timestamp is the calibrated local UTC time.

8. The calculation method for determining satellite azimuth and elevation using TLE data as described in claim 1, characterized in that, The broadcast satellite position data format includes three-dimensional coordinate values ​​in the geocentric coordinate system and the corresponding first UTC timestamp, and is encapsulated in JSON or binary protocol.

9. The calculation method for determining satellite azimuth and elevation using TLE data as described in claim 6, characterized in that, The transformation from the geocentric coordinate system to the local coordinate system uses a transformation matrix from the geocentric geodetic coordinate system ECEF to the station-centric coordinate system ENU. The transformation parameters include the geodetic latitude, longitude, and elevation of the ground station.

10. The calculation method for determining satellite azimuth and elevation using TLE data as described in claim 3, characterized in that, The preset threshold is that the angle between the satellite velocity vector and the position deviation vector is less than 30 degrees.

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