Space-based directional observation method and device based on orbit precision evaluation

Abstract

The invention discloses a space-based directional observation method and device based on orbit precision evaluation. The method comprises the following steps: acquiring fixed star angular distance measurement data information, a Ka-band inter-satellite link observation value and an L-band satellite-ground link observation value of a Beidou satellite; using the information to construct a multi-dimensional observation matrix and carrying out resolving processing to obtain satellite position parameters corresponding to the three space-based directional observation modes; and performing comparison processing on the satellite position parameters by taking an MGEX precise ephemeris as a comparison baseline to obtain an optimal observation mode. Therefore, three space-based directional observation modes are provided, the orbit precision is used as an evaluation criterion, an observation mode system with high adaptability and high practicability is formed, and the orbit determination precision of the Beidou satellite is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite navigation, and particularly to a space-based directional observation method and device based on orbit accuracy evaluation. Background Art

[0002] In the field of deep space measurement, it is necessary to focus on exploring the integrated application of navigation measurement technology and space-based directional measurement technology based on star sensors, aiming to solve the problems of navigation measurement accuracy and coverage in complex environments. However, due to the immature specific design of the space-based directional measurement mode, this technology integration mode is still in the exploratory demonstration stage and requires further research and optimization.

[0003] As a technical method that breaks through the limitations of traditional ground measurement, space-based directional measurement provides a new solution idea for navigation tasks in complex scenarios. Its core lies in observing target satellites and background stars through high-precision star sensors to obtain interstellar direction information, so as to accurately determine the direction of the target satellite connection line in inertial space; at the same time, combined with the high-precision interstellar ranging obtained through the interstellar link (such as Ka band), the orbit data solution can be further optimized. The two complement each other, not only significantly improving the accuracy of the navigation satellite orbit data, but also showing excellent advantages in the estimation performance of the orbital plane orientation elements. However, the current research work mainly focuses on verifying the navigation satellite autonomous orbit determination method supported by space-based directional measurement, and mostly focuses on theoretical feasibility analysis and algorithm correctness verification, and has not carried out in-depth research on the adaptive design of the measurement mode and actual engineering implementation. This limitation directly restricts the popularization and application of space-based directional measurement technology in engineering practice, and the scientific and reasonable design of the space-based directional measurement mode is of decisive significance for its effective implementation in complex navigation tasks. Summary of the Invention

[0004] The object of the present invention is to propose a space-based directional observation method and device based on orbit accuracy evaluation to solve the above problems.

[0005] To achieve the above object, in the first aspect of the embodiments of the present invention, a space-based directional observation method based on orbit accuracy evaluation is disclosed, and the method includes:

[0006] S1. Obtain the star angular distance measurement data information of Beidou satellites under three space-based directional observation modes; the three space-based directional observation modes include a staring measurement mode, a short-period round-robin measurement mode, and a long-period round-robin measurement mode; the star angular distance measurement data information includes a first-mode star angular distance measurement data set, a second-mode star angular distance measurement data set, and a third-mode star angular distance measurement data set; the star angular distance measurement data includes the relative right ascension and relative declination data of interstellar objects in the celestial coordinate system; preferably, the observation duration is not less than 15 days;

[0007] S2. Use the Ka inter-satellite link for inter-satellite observations to obtain Ka-band inter-satellite link observation values;

[0008] S3. Use the Beidou system monitoring stations for L-band satellite-ground observations to obtain L-band satellite-ground link observation values;

[0009] S4. According to the measured data information of the stellar angular distance, the Ka-band inter-satellite link observation values, and the L-band satellite-ground link observation values, construct a multi-dimensional observation matrix and perform solution processing to obtain the satellite position parameters corresponding to the three space-based directional observation modes;

[0010] S5. Use the MGEX precise ephemeris as a comparison baseline to compare the satellite position parameters corresponding to the three space-based directional observation modes to obtain the optimal observation mode.

[0011] As an optional implementation manner, in the first aspect of the embodiments of the present invention, the three space-based directional observation modes specifically include:

[0012] The staring measurement mode includes: using 3 Beidou IGSO (Inclined Geosynchronous Orbit) satellites to perform staring observations on 24 Beidou MEO (Medium Earth Orbit) satellites; the 24 MEO satellites are distributed on 3 orbital planes, and each IGSO satellite fixedly observes a visible MEO satellite on a certain orbital plane; when the MEO satellite is not visible, switch to observe other visible MEO satellites in the same orbital plane; each IGSO satellite generates a piece of measured data of the stellar angular distance at each observation moment and observes once every 15 minutes to obtain the first-mode measured data set of the stellar angular distance.

[0013] The short-period patrol measurement mode uses the first time period as the short patrol cycle, and the first time period is not less than 1 hour and not more than 2 hours; within each short patrol cycle, 3 Beidou IGSO satellites respectively perform patrol observations on the MEO satellites on three orbits, and each IGSO satellite fixedly observes any visible MEO satellite on the orbital plane and observes once every 15 minutes; at the start of the next short patrol cycle, the IGSO satellite switches to another orbital plane, and the 3 IGSO satellites switch according to the same rule to ensure that MEO satellites on all 3 orbital planes participate in the observation within each short patrol cycle, and each IGSO satellite selects any visible MEO satellite on the observed orbital plane for observation, and generates a piece of measured data of the stellar angular distance at each observation moment to obtain the second-mode measured data set of the stellar angular distance.

[0014] The long - period round - robin measurement mode uses the second time duration as the long round - robin period, where the second time duration is not less than 8 hours and not more than 12 hours; within each long round - robin period, 3 Beidou IGSO satellites respectively conduct round - robin observations on MEO satellites in three orbits through star sensors. Each IGSO satellite fixedly observes any visible MEO satellite on the orbital plane, and makes an observation every 15 minutes; at the start of the next long round - robin period, the IGSO satellites switch to another orbital plane, and the 3 IGSO satellites switch according to the same rule to ensure that MEO satellites in all 3 orbital planes participate in observations within each long round - robin period. Each IGSO satellite selects any visible MEO satellite on the observed orbital plane for observation, and a set of stellar angular distance measurement data is generated at each observation moment, obtaining the stellar angular distance measurement data set of the third mode.

[0015] As an optional implementation manner, in the first aspect of the embodiments of the present invention, the obtaining of the Ka - band inter - satellite link observation value by using the Ka inter - satellite link for inter - satellite observation includes:

[0016] Based on the Beidou system Ka - band inter - satellite observation link, based on the inter - satellite pseudorange observation value Extract the inter - satellite link observation value The corresponding expression is:

[0017]

[0018] where c is the speed of light, and are respectively the transmission delay and reception delay of the inter - satellite link equipment of satellite A, and are respectively the transmission delay and reception delay of the inter - satellite link equipment of satellite B, and are respectively the error correction terms in the inter - satellite observation, including the satellite antenna phase center and the relativistic effect, both of which can be accurately modeled and corrected using known models. The data sampling interval is taken as 15 minutes.

[0019] As an optional implementation manner, the obtaining of the L - band satellite - to - ground link observation value by using the Beidou system monitoring stations for L - band satellite - to - ground observation includes:

[0020] Domestic Beidou monitoring stations are respectively deployed in Hainan region, Beijing region, Northeast region, Xinjiang region, Fujian region, and Sichuan region. Conduct L - band satellite - to - ground link observations from the above - mentioned monitoring stations, with the data sampling interval taken as 15 minutes, to obtain the L - band satellite - to - ground link observation value of the monitoring station at time t k denoted as

[0021] As an alternative implementation, in the first aspect of the embodiments of the present invention, based on the stellar angular distance measurement data information, Ka-band inter-satellite link observations, and L-band satellite-ground link observations, a multi-dimensional observation matrix is constructed and processed by resolution to obtain satellite position parameters corresponding to three space-based orientation observation modes, including:

[0022] S41. Integrate and process the stellar angular distance measurement data information, Ka-band inter-satellite link observations, and L-band satellite-ground link observations to obtain a multi-dimensional observation matrix corresponding to three space-based orientation observation modes;

[0023] The multi-dimensional observation matrix is expressed as:

[0024]

[0025] In the formula, t k represents the observation time, L orb (t k ) represents the multi-dimensional observation matrix, represents the Ka-band inter-satellite link observation value, represents the L-band satellite-ground link observation value, represents the stellar angular distance measurement data in the i-th mode, respectively represent the relative right ascension and relative declination of the direction connecting the inter-satellite observation satellites A and B in the celestial coordinate system, and the i-th mode is one of the three space-based orientation observation modes;

[0026] S42. According to the multi-dimensional observation matrix corresponding to three space-based orientation observation modes, construct multi-dimensional observation equations corresponding to three space-based orientation observation modes;

[0027] The multi-dimensional observation equations are specifically as follows:

[0028]

[0029] In the formula, L orb (t k ) represents the multi-dimensional observation matrix, X orb (t k ) is the position parameter of the Beidou satellite at epoch t k . When k = 1, t k is t1, which is the starting time. The position parameter X orb (t1) of the Beidou satellite is taken as the quantity to be estimated, Δ orb is the orbital observation noise vector, and A orb is the satellite position coefficient matrix, which expresses the relationship between the observed quantity and the satellite position vector, and can be specifically expressed as:

[0030]

[0031] S43. Based on the multi-dimensional observation equations corresponding to the three space-based orientation observation modes, perform solution by the least squares algorithm to obtain the satellite position parameters corresponding to the three space-based orientation observation modes;

[0032] The satellite position parameters are expressed as:

[0033] X orb (t k ) = (A orb T ·A orb ) -1 ·A orb T ·L orb (t k ).

[0034] As an alternative implementation manner, in the first aspect of the embodiments of the present invention, taking the MGEX precise ephemeris as a comparison baseline, performing comparison processing on the satellite position parameters corresponding to the three space-based orientation observation modes to obtain the optimal observation mode, includes:

[0035] S51. Obtain the precise ephemeris of Beidou satellites from MGEX to obtain the reference satellite position parameter information; the epoch of the reference satellite position parameter information is the same as the epoch of the satellite position parameters corresponding to the three space-based orientation observation modes;

[0036] It should be noted that the precise ephemeris of Beidou satellites obtained by MGEX refers to the Beidou precise ephemeris released by the International Organization of the Multi-GNSS Experiment Tracking Network, which is public information.

[0037] S52. Based on the reference satellite position parameter information, perform error calculation processing on the satellite position parameters corresponding to the three space-based orientation observation modes to obtain the error values corresponding to the three space-based orientation observation modes;

[0038] S53. According to the error values corresponding to the three space-based orientation observation modes, select the space-based orientation observation mode corresponding to the error value as the optimal observation mode.

[0039] As an alternative implementation manner, in the first aspect of the embodiments of the present invention, the performing error calculation processing on the satellite position parameters corresponding to the three space-based orientation observation modes based on the reference satellite position parameter information to obtain the error values corresponding to the three space-based orientation observation modes includes:

[0040] S521. Calculate the root mean square error of the difference between the satellite position parameters corresponding to any space-based orientation observation mode and the reference satellite position parameter information in chronological order of epochs to obtain the error value of the any space-based orientation observation mode;

[0041] S522. Execute step S521 in a loop to obtain the error values corresponding to the three space-based directional observation modes.

[0042] In the second aspect of the embodiments of the present invention, a space-based directional observation device based on orbit accuracy evaluation is disclosed. By using the space-based directional observation method disclosed in the first aspect of the embodiments of the present invention, the device includes:

[0043] A stellar angular distance measurement data acquisition module; configured to acquire the stellar angular distance measurement data information of the Beidou satellite under three space-based directional observation modes; the three space-based directional observation modes include a staring measurement mode, a short-period patrol measurement mode, and a long-period patrol measurement mode; the stellar angular distance measurement data information includes a first-mode stellar angular distance measurement data set, a second-mode stellar angular distance measurement data set, and a third-mode stellar angular distance measurement data set; the stellar angular distance measurement data includes the relative right ascension and relative declination data between stars in the celestial coordinate system.

[0044] A Ka-band inter-satellite link observation value acquisition module, configured to perform inter-satellite observation using the Ka inter-satellite link to acquire Ka-band inter-satellite link observation values.

[0045] An L-band satellite-ground link observation value acquisition module, configured to perform L-band satellite-ground observation using the Beidou system monitoring station to acquire L-band satellite-ground link observation values.

[0046] A satellite position parameter calculation module, configured to construct a multi-dimensional observation matrix and perform a solution process based on the stellar angular distance measurement data information, Ka-band inter-satellite link observation values, and L-band satellite-ground link observation values to obtain the satellite position parameters corresponding to the three space-based directional observation modes.

[0047] An observation mode determination module, taking the MGEX precise ephemeris as a comparison baseline, performs a comparison process on the satellite position parameters corresponding to the three space-based directional observation modes to obtain the optimal observation mode.

[0048] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0049] A space-based directional observation method and device based on orbit accuracy evaluation disclosed in an embodiment of the present invention, based on the actual on-orbit operation status of Beidou satellites, proposes three space-based directional observation modes: a staring measurement mode, a short-period patrol measurement mode, and a long-period patrol measurement mode. Taking orbit accuracy as the evaluation criterion, by systematically planning the star sensor layout scheme, dynamically adjusting the observation strategy, and fusing inter-satellite link ranging and direction observation data, a set of observation mode systems with strong adaptability and high practicability is formed, significantly improving the orbit determination accuracy of navigation satellites, taking into account high-precision measurement and resource optimization utilization, adapting to different mission scenario requirements, and providing a theoretical basis and technical guarantee for high-precision orbit measurement and complex navigation tasks in the Beidou system.

[0050] (1) Multi-mode design to improve the adaptability and reliability of orbit accuracy

[0051] The present invention proposes three space-based directional observation modes, which improve the adaptability and accuracy of orbit measurement by flexibly adjusting the observation strategy according to different mission requirements and scenarios. The multi-mode design fully considers high-dynamic scenarios, global coverage requirements, and long-term observation redundancy, enabling the system to stably output high-precision orbit data in complex environments.

[0052] (2) Evaluation method based on precise ephemeris to ensure the optimization of observation modes

[0053] By taking the MGEX precise ephemeris as the benchmark, evaluating the error of position parameters under different observation modes, and using the root mean square error (RMS) as the accuracy measurement standard, it is ensured that the selected observation mode has the highest orbit accuracy. This method provides a systematic means for optimizing the observation mode, not only ensuring the high-precision requirements for Beidou satellite orbit solution, but also providing a scientific basis and technical support for future high-precision navigation tasks. Description of the Drawings

[0054] Figure 1 Schematic diagram of a space-based directional observation method based on orbit accuracy evaluation disclosed in an embodiment of the present invention;

[0055] Figure 2 Schematic diagram of three space-based directional observation modes disclosed in an embodiment of the present invention;

[0056] Figure 3 Schematic diagram of the solution of a space-based directional observation method based on orbit accuracy evaluation disclosed in an embodiment of the present invention;

[0057] Figure 4 Schematic diagram of the structure of a space-based directional observation device based on orbit accuracy evaluation disclosed in an embodiment of the present invention. Detailed Embodiment

[0058] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0059] Embodiment 1

[0060] Please refer to Figure 1 。 Figure 1 It is a schematic diagram of a space-based directional observation method based on orbit accuracy evaluation disclosed in an embodiment of the present invention. Among them, Figure 1 The described space-based directional observation method based on orbit accuracy evaluation is applied to a management system, such as a local server or a cloud server for management, etc., which is not limited in the embodiments of the present invention.

[0061] Such as Figure 1 As shown, the space-based directional observation method based on orbit accuracy evaluation disclosed in the embodiments of the present invention includes:

[0062] S1. Obtain the star angular distance measurement data information of Beidou satellites in three space-based directional observation modes; the three space-based directional observation modes include a staring measurement mode, a short-period patrol measurement mode, and a long-period patrol measurement mode; the star angular distance measurement data information includes a first-mode star angular distance measurement data set, a second-mode star angular distance measurement data set, and a third-mode star angular distance measurement data set; the star angular distance measurement data includes the relative right ascension and relative declination data between stars in the celestial coordinate system; preferably, the observation duration is not less than 15 days;

[0063] S2. Perform inter-satellite observations using the Ka inter-satellite link to obtain Ka-band inter-satellite link observation values;

[0064] S3. Perform L-band satellite-ground observations using the Beidou system monitoring station to obtain L-band satellite-ground link observation values;

[0065] S4. According to the star angular distance measurement data information, Ka-band inter-satellite link observation values, and L-band satellite-ground link observation values, construct a multi-dimensional observation matrix and perform resolution processing to obtain satellite position parameters corresponding to the three space-based directional observation modes;

[0066] S5. Take the MGEX precise ephemeris as a comparison baseline, perform comparison processing on the satellite position parameters corresponding to the three space-based directional observation modes, and obtain the optimal observation mode.

[0067] As an optional implementation manner, please refer to Figure 2 , Figure 2 It is a schematic diagram of three space-based directional observation modes disclosed in an embodiment of the present invention, such asFigure 2 As shown, the three space-based directional observation modes specifically include:

[0068] The staring measurement mode includes: using 3 Beidou IGSO (Inclined Geosynchronous Orbit) satellites to conduct staring observations on 24 Beidou MEO (Medium Earth Orbit) satellites; the 24 MEO satellites are distributed on 3 orbital planes, and each IGSO satellite fixedly observes a visible MEO satellite on a certain orbital plane; when the MEO satellite is not visible, switch to observe other visible MEO satellites within the same orbital plane; each IGSO satellite generates a set of stellar angular distance measurement data at each observation moment, and observes once every 15 minutes to obtain the first-mode stellar angular distance measurement data set.

[0069] It should be noted that the staring measurement mode conducts long-term continuous observations on specific target satellites through star sensors, focusing on obtaining high-precision data, and is suitable for the orbital accuracy optimization requirements of key regions or specific mission scenarios.

[0070] The short-period patrol measurement mode uses the first time period as the short patrol cycle, and the first time period is not less than 1 hour and not more than 2 hours; within each short patrol cycle, 3 Beidou IGSO satellites respectively conduct patrol observations on the MEO satellites on three orbits through star sensors. Each IGSO satellite fixedly observes any visible MEO satellite on the orbital plane and observes once every 15 minutes; at the start of the next short patrol cycle, the IGSO satellite switches to another orbital plane, and the 3 IGSO satellites switch according to the same rule to ensure that MEO satellites on all 3 orbital planes participate in the observation within each short patrol cycle. Each IGSO satellite selects any visible MEO satellite on the observed orbital plane for observation; a set of stellar angular distance measurement data is generated at each observation moment to obtain the second-mode stellar angular distance measurement data set.

[0071] In the short-period patrol measurement mode, all orbital planes are dynamically covered, improving the uniformity and efficiency of the observation. Dynamically adjusting the observation target of the star sensor takes into account both the breadth of orbital coverage and the continuity of measurement data, and is applicable to the accuracy evaluation of multi-target dynamic scenarios.

[0072] The long-period patrol measurement mode uses the second time period as the long patrol cycle, where the second time period is not less than 8 hours and not more than 12 hours; within each long patrol cycle, 3 Beidou IGSO satellites respectively conduct patrol observations on MEO satellites in three orbits through star sensors. Each IGSO satellite fixedly observes any visible MEO satellite on its orbital plane and observes once every 15 minutes; at the start of the next long patrol cycle, the IGSO satellites switch to another orbital plane, and the 3 IGSO satellites switch according to the same rule to ensure that MEO satellites in all 3 orbital planes participate in observations within each long patrol cycle. Each IGSO satellite selects any visible MEO satellite on the observed orbital plane for observation, and one set of stellar angular distance measurement data is generated at each observation moment, obtaining the stellar angular distance measurement data set of the third mode.

[0073] It should be noted that the long-period patrol measurement mode plans the observation tasks with a longer observation cycle, improves the global orbital accuracy and consistency through redundant observations, and is applicable to the orbital data optimization of global navigation tasks.

[0074] Different from the short-period patrol measurement mode, the long-period patrol measurement mode extends the patrol switching interval. Within each patrol cycle, the angle measurement observations are carried out at 15-minute intervals, and 3 sets of angle measurement data are generated at the same measurement moment. By extending the patrol cycle, this mode is applicable to long-term global observation tasks and reduces the resource consumption caused by frequent switching at the same time.

[0075] It should be noted that the stellar angular distance measurement data obtained under the above three space-based directional observation modes have certain differences in measurement accuracy according to different observation modes, which are specifically expressed as:

[0076]

[0077] Among them, (x A , y A , z A ) and (x B , y B , z B ) are the position vectors of satellite A and satellite B in the inertial coordinate system and and are the observation errors (about 5 mas magnitude) in the i-th observation mode respectively.

[0078] As an optional implementation method, the inter-satellite observation using the Ka inter-satellite link to obtain Ka-band inter-satellite link observation values includes:

[0079] Based on the Beidou system Ka-band inter-satellite observation link, based on the inter-satellite pseudorange observation values Extract the inter-satellite link observation values The corresponding expression is:

[0080]

[0081] where c is the speed of light, and are the transmission delay and reception delay of the inter-satellite link device of satellite A respectively, and are the transmission delay and reception delay of the inter-satellite link device of satellite B respectively, and are the error correction terms in the inter-satellite observation, including the satellite antenna phase center and the relativistic effect, both of which can be accurately modeled and corrected using known models. The data sampling interval is taken as 15 minutes.

[0082] As an alternative implementation, the use of the Beidou system monitoring stations for L-band space-ground observation to obtain L-band space-ground link observation values includes:

[0083] Domestic Beidou monitoring stations are respectively deployed in Hainan region, Beijing region, Northeast region, Xinjiang region, Fujian region, and Sichuan region. Conduct L-band space-ground link observation from the above monitoring stations, with the data sampling interval taken as 15 minutes, to obtain the k L-band space-ground link observation values of the monitoring stations at time t, denoted as

[0084] The above-mentioned space-ground link observation values of the monitoring stations are the original pseudo-range phase observation data. Perform necessary data preprocessing and use the existing accurate navigation measurement model to achieve the phase center correction of the station antenna and satellite antenna, the correction of tropospheric and ionospheric delay errors, the correction of relativistic effects, and the correction of earth tide errors.

[0085] For the correction of the satellite antenna phase center, it is necessary to first convert the satellite mechanical coordinate system to the satellite orbit coordinate system and then to the J2000 inertial system to give the phase center deviation during calculation.

[0086] Converting the satellite mechanical coordinate system to the satellite orbit coordinate system requires 3 times of coordinate axis rotation. 1) Rotate around the z s axis by the yaw angle; 2) Rotate around the y s axis by the pitch angle; 3) Rotate around the x s axis by the roll angle. The calculation formula for converting the satellite mechanical coordinate system to the satellite orbit coordinate system is as follows:

[0087]

[0088] where It is the position of the antenna phase center in the mechanical coordinate system relative to the origin (geometric center) of the mechanical coordinate system; the three rotation matrices are expressed as follows, with the angle being positive for counterclockwise rotation.

[0089]

[0090]

[0091] The three attitude angles (roll, pitch, yaw) are obtained from the telemetry data of the satellite attitude.

[0092] The phase center deviation is given in the satellite reference coordinate system, and the satellite reference coordinate system is defined as: the origin is at the satellite's center of mass, the Z-axis points to the center of the Earth, the X-axis is the satellite's motion direction, and the Y-axis forms a right-handed coordinate system with the Z-axis and X-axis. That is:

[0093]

[0094] where and are the position and velocity vectors of the satellite in the inertial system respectively.

[0095] The conversion relationship from the satellite reference coordinate system to the J2000 inertial system is as follows:

[0096]

[0097] Therefore, the model of the satellite antenna phase center correction ΔD SatAnt is:

[0098]

[0099] For the relativistic effect, the distance correction ΔD CRel caused by the influence of the periodic term can be calculated using the following formula:

[0100]

[0101] where X S 、 are the position and velocity vectors of the satellite respectively, and c is the speed of light.

[0102] For the ground station antenna phase center correction, precise calibration is carried out during the factory production process of the ground measurement equipment, and the calibration results are provided for users. Therefore, this error can be corrected using the parameters provided by the manufacturer.

[0103] For tropospheric delay error, the meteorological observation data measured at the tracking stations are used to correct this error in the orbit determination calculation. The pseudo-range phase observation data are all corrected for the error using the Saastamoinen-Neil model. In this model, the tropospheric delay error can be calculated by inputting the temperature, air pressure, and humidity.

[0104] For ionospheric delay error, the dual-frequency ionosphere-free combination is adopted where f1 and f2 are the frequencies of the two frequency points respectively, and L1 and L2 are the pseudo-range observables of the two frequency points. Through the L C combination, the influence of the ionospheric error can be eliminated for ionospheric error correction. Under the condition of only single-frequency observation, the global precise ionospheric delay model provided by the Center for Orbit Determination in Europe (CODE) is adopted, and the ionospheric delay amount of the piercing point corresponding to each monitoring station and the satellite is calculated using the global ionospheric delay map.

[0105] For the earth tide error, it can be calculated using the following formula:

[0106]

[0107] In the formula, GM is the gravitational constant of the earth; GM j is the gravitational constant of the tide-generating celestial body (when j = 2, it is the moon, and when j = 3, it is the sun), r and R j are the geocentric positions of the observation station and the tide-generating celestial body respectively, are the corresponding unit vectors, h2 is the Love number, and l2 is the Shida number.

[0108] As an alternative implementation, based on the star angular distance measurement data information, Ka-band inter-satellite link observations, and L-band satellite-ground link observations, a multi-dimensional observation matrix is constructed and processed by solving to obtain the satellite position parameters corresponding to three space-based orientation observation modes, including:

[0109] S41. Integrate and process the star angular distance measurement data information, Ka-band inter-satellite link observations, and L-band satellite-ground link observations to obtain a multi-dimensional observation matrix corresponding to three space-based orientation observation modes;

[0110] The multi-dimensional observation matrix is expressed as:

[0111]

[0112] In the formula, t k represents the observation time, and L orb (t k ) represents the multi-dimensional observation matrix, represents the Ka-band inter-satellite link observation value, represents the L-band satellite-ground link observation value, Indicates the stellar angular distance measurement data in the i mode, respectively representing the relative right ascension and relative declination in the direction of the line connecting the inter-satellite observation satellites A and B in the celestial coordinate system, and the i mode is one of the three space-based directional observation modes;

[0113] S42. Construct multi-dimensional observation equations corresponding to the three space-based directional observation modes according to the multi-dimensional observation matrices corresponding to the three space-based directional observation modes;

[0114] The specific form of the multi-dimensional observation equation is as follows:

[0115]

[0116] In the formula, L orb (t k ) represents the multi-dimensional observation matrix, X orb (t k ) is the position parameter of the Beidou satellite at epoch t k . When k = 1, t k is the moment t1, which is the starting moment. The position parameter X orb (t1) is taken as the quantity to be estimated, Δ orb is the orbital observation noise vector, A orb is the satellite position coefficient matrix, which expresses the relationship between the observed quantity and the satellite position vector, and can be specifically expressed as:

[0117]

[0118] It should be noted that the dynamic model used for orbit determination includes the central gravitational force of the Earth on the satellite, conservative force perturbations, and non-conservative force perturbations. Among them, the conservative force perturbations include N-body perturbations, Earth shape perturbations, solid tides, and ocean tide perturbations, and the non-conservative force perturbations include solar direct radiation pressure perturbations, Earth albedo radiation pressure perturbations, and satellite body radiation perturbations; the Earth's gravitational field adopts the 10×10 order JGM-3 model, the planetary ephemeris adopts the JPL DE403 parameters, the nutation model adopts the IAU80 model, the solar radiation pressure model adopts the ECOM5 model, and the solid tide adopts the IERS96 model.

[0119] S43. Based on the multi-dimensional observation equations corresponding to the three space-based directional observation modes, perform calculations through the least squares algorithm to obtain the satellite position parameters corresponding to the three space-based directional observation modes;

[0120] The satellite position parameters are expressed as:

[0121] X orb (t k )=(A orb T ·A orb )-1 ·A orb T ·L orb (t k )。

[0122] As an alternative implementation, taking the MGEX precise ephemeris as the comparison baseline, comparing and processing the satellite position parameters corresponding to the three space-based directional observation modes to obtain the optimal observation mode, including:

[0123] S51. Obtain the precise ephemeris of Beidou satellites from MGEX to obtain the reference satellite position parameter information; the epoch of the reference satellite position parameter information is the same as the epoch of the satellite position parameters corresponding to the three space-based directional observation modes;

[0124] It should be noted that the precise ephemeris of Beidou satellites obtained by MGEX refers to the Beidou precise ephemeris released by the International Multi-GNSS Experiment (MGEX) Tracking Network, which is public information.

[0125] S52. Based on the reference satellite position parameter information, perform error calculation and processing on the satellite position parameters corresponding to the three space-based directional observation modes to obtain the error values corresponding to the three space-based directional observation modes;

[0126] S53. According to the error values corresponding to the three space-based directional observation modes, select the space-based directional observation mode corresponding to the error value as the optimal observation mode.

[0127] As an alternative implementation, the performing error calculation and processing on the satellite position parameters corresponding to the three space-based directional observation modes based on the reference satellite position parameter information to obtain the error values corresponding to the three space-based directional observation modes includes:

[0128] S521. Calculate the root mean square error of the difference between the satellite position parameters corresponding to any space-based directional observation mode and the reference satellite position parameter information in chronological order of epochs to obtain the error value of the any space-based directional observation mode;

[0129] S522. Loop and execute step S521 to obtain the error values corresponding to the three space-based directional observation modes.

[0130] It should be noted that the root mean square error reflects the deviation degree between the solved position parameters and the reference precise ephemeris. The smaller the error value, the higher the accuracy of the position parameters.

[0131] It should be noted that the data solving process can refer to Figure 3 , Figure 3 which is the schematic diagram of the solution of a space-based directional observation method based on orbit accuracy evaluation disclosed in the embodiments of the present invention.

[0132] Embodiment 2

[0133] Please refer to Figure 4 . Figure 4 The figure is a schematic structural diagram of a space-based directional observation device based on orbital accuracy evaluation disclosed in an embodiment of the present invention. Among them, Figure 4 The described device can be applied to a management system, such as a local server or a cloud server for management, etc., and the embodiments of the present invention do not make limitations. As Figure 4 shown, the device may include:

[0134] A stellar angular distance measurement data acquisition module 201; used to obtain the stellar angular distance measurement data information of Beidou satellites under three space-based directional observation modes; the three space-based directional observation modes include a staring measurement mode, a short-period round-robin measurement mode, and a long-period round-robin measurement mode; the stellar angular distance measurement data information includes a first-mode stellar angular distance measurement data set, a second-mode stellar angular distance measurement data set, and a third-mode stellar angular distance measurement data set; the stellar angular distance measurement data includes the relative right ascension and relative declination data between stars in the celestial sphere coordinate system;

[0135] A Ka-band inter-satellite link observation value acquisition module 202, used to perform inter-satellite observations using the Ka inter-satellite link to obtain Ka-band inter-satellite link observation values;

[0136] An L-band satellite-ground link observation value acquisition module 203, used to perform L-band satellite-ground observations using the Beidou system monitoring station to obtain L-band satellite-ground link observation values;

[0137] A satellite position parameter calculation module 204, used to construct a multi-dimensional observation matrix and perform solution processing based on the stellar angular distance measurement data information, Ka-band inter-satellite link observation values, and L-band satellite-ground link observation values to obtain satellite position parameters corresponding to the three space-based directional observation modes;

[0138] An observation mode determination module 205, taking the MGEX precise ephemeris as a comparison baseline, performs comparison processing on the satellite position parameters corresponding to the three space-based directional observation modes to obtain the optimal observation mode.

[0139] Embodiment 2 of this embodiment is the product embodiment corresponding to Embodiment 1. The steps and methods included are the same as those in Embodiment 1 and will not be elaborated in Embodiment 2.

[0140] The device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules. That is, they may be located in one place or distributed to multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0141] Through the specific descriptions of the above embodiments, those skilled in the art can clearly understand that each implementation can be achieved by means of software plus a necessary general hardware platform, and of course, it can also be achieved by hardware. Based on this understanding, the essence of the above technical solution, or the part 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, including read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electrically-erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc memories, magnetic disk memories, tape memories, or any other computer-readable medium capable of carrying or storing data.

[0142] Finally, it should be noted that the disclosed method and device for space-based directional observation based on orbit accuracy evaluation according to the embodiments of the present invention are only the preferred embodiments of the present invention, and are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A space-based directional observation method based on orbital accuracy evaluation, characterized in that, The method includes: S1. Obtain the star angular distance measurement data information under three space-based directional observation modes; the three space-based directional observation modes include the staring measurement mode, the short-period patrol measurement mode, and the long-period patrol measurement mode; the star angular distance measurement data information includes the first-mode star angular distance measurement data set, the second-mode star angular distance measurement data set, and the third-mode star angular distance measurement data set; the star angular distance measurement data includes the relative right ascension data and relative declination data of stars in the celestial sphere coordinate system; S2. Use the Ka inter-satellite link for inter-satellite observation to obtain Ka-band inter-satellite link observation values; S3. Use the Beidou system monitoring station for L-band space-ground observation to obtain L-band space-ground link observation values; S4. According to the star angular distance measurement data information, the Ka-band inter-satellite link observation values, and the L-band space-ground link observation values, construct a multi-dimensional observation matrix and perform resolution processing to obtain the satellite position parameters corresponding to the three space-based directional observation modes; S5. Take the MGEX precise ephemeris as the comparison baseline, perform comparison processing on the satellite position parameters corresponding to the three space-based directional observation modes to obtain the optimal observation mode.

2. The space-based directional observation method based on orbital accuracy evaluation according to claim 1, wherein The three space-based directional observation modes specifically include: The staring measurement mode includes: using 3 Beidou IGSO satellites to stare at 24 Beidou MEO satellites; each IGSO satellite fixedly observes one visible MEO satellite on an orbital plane; when the MEO satellite is not visible, switch to observe other visible MEO satellites in the same orbital plane; each IGSO satellite generates a star angular distance measurement data at each observation moment and observes once every 15 minutes to obtain the first-mode star angular distance measurement data set; The short-period patrol measurement mode uses the first duration as the short patrol period, and the first duration is not less than 1 hour and not more than 2 hours; within each short patrol period, 3 Beidou IGSO satellites respectively perform patrol observations on the MEO satellites in three orbits. Each IGSO satellite fixedly observes any visible MEO satellite on the orbital plane and observes once every 15 minutes; at the start of the next short patrol period, the IGSO satellite switches to another orbital plane, and the 3 IGSO satellites switch according to the same rule to ensure that MEO satellites in all 3 orbital planes participate in the observation within each short patrol period. Each IGSO satellite selects any visible MEO satellite on the observed orbital plane for observation, and generates a star angular distance measurement data at each observation moment to obtain the second-mode star angular distance measurement data set; The long-period patrol measurement mode uses the second time period as the long patrol cycle, where the second time period is not less than 8 hours and not more than 12 hours; within each long patrol cycle, 3 Beidou IGSO satellites respectively conduct patrol observations on MEO satellites in three orbits. Each IGSO satellite fixedly observes any visible MEO satellite on the orbital plane. Observations are made every 15 minutes; at the start of the next long patrol cycle, the IGSO satellites switch to another orbital plane, and the 3 IGSO satellites switch according to the same rule to ensure that MEO satellites in all three orbital planes participate in observations within each long patrol cycle. Each IGSO satellite selects any visible MEO satellite on the observed orbital plane for observation, and a set of stellar angular distance measurement data is generated at each observation moment, obtaining the stellar angular distance measurement data set for the third mode.

3. The space-based directional observation method based on orbital accuracy evaluation according to claim 1, characterized in that Based on the stellar angular distance measurement data information, the Ka-band inter-satellite link observation values, and the L-band satellite-ground link observation values, construct a multi-dimensional observation matrix and perform resolution processing to obtain the satellite position parameters corresponding to the three space-based directional observation modes, including: S41. Integrate and process the stellar angular distance measurement data information, the Ka-band inter-satellite link observation values, and the L-band satellite-ground link observation values to obtain the multi-dimensional observation matrix corresponding to the three space-based directional observation modes; The multi-dimensional observation matrix is expressed as: Where t k represents the observation time, and L orb (t k ) represents the multi-dimensional observation matrix, represents the Ka-band inter-satellite link observation value, represents the L-band satellite-ground link observation value, represents the stellar angular distance measurement data in the i mode, respectively represent the relative right ascension and relative declination in the direction of the line connecting the inter-satellite observation satellites A and B in the celestial coordinate system, and the i mode is one of the three space-based directional observation modes; S42. Based on the multi-dimensional observation matrix corresponding to the three space-based directional observation modes, construct the multi-dimensional observation equations corresponding to the three space-based directional observation modes; The specific multi-dimensional observation equations are as follows: where L orb (t k ) represents a multi-dimensional observation matrix, X orb (t k ) is the position parameter of the Beidou satellite at epoch t k . When k = 1, t k is t1, the starting epoch. The position parameter X orb (t1) is taken as the quantity to be estimated, Δ orb is the orbital observation noise vector, and A orb is the satellite position coefficient matrix, which expresses the relationship between the observed quantity and the satellite position vector and can be specifically expressed as; S43. Solve the multi-dimensional observation equations corresponding to the three space-based directional observation modes to obtain the satellite position parameters corresponding to the three space-based directional observation modes; The satellite position parameters are expressed as: X orb (t k )=(A orb T ·A orb ) -1 ·A orb T ·L orb (t k )。 4. The space-based directional observation method based on orbital accuracy assessment according to claim 1, characterized in that, Using the MGEX precise ephemeris as the comparison baseline, compare and process the satellite position parameters corresponding to the three space-based directional observation modes to obtain the optimal observation mode, including: S51. Obtain the precise ephemeris of Beidou satellites from MGEX to obtain the reference satellite position parameter information; the epoch of the reference satellite position parameter information is the same as the epoch of the satellite position parameters corresponding to the three space-based directional observation modes; S52. Based on the reference satellite position parameter information, perform error calculation processing on the satellite position parameters corresponding to the three space-based directional observation modes to obtain the error values corresponding to the three space-based directional observation modes; S53. According to the error values corresponding to the three space-based directional observation modes, select the space-based directional observation mode corresponding to the minimum error value as the optimal observation mode.

5. The space-based directional observation method based on orbital accuracy evaluation according to claim 1, characterized in that Based on the reference satellite position parameter information, performing error calculation processing on the satellite position parameters corresponding to the three space-based directional observation modes to obtain the error values corresponding to the three space-based directional observation modes includes: S521. Calculate the root mean square error of the difference between the satellite position parameters corresponding to any space-based directional observation mode and the reference satellite position parameter information in chronological order of epochs to obtain the error value of the said space-based directional observation mode; S522. Loop and execute step S521 to obtain the error values corresponding to the three space-based directional observation modes.

6. A space-based directional observation device based on orbital accuracy evaluation, characterized in that, The device includes: A stellar angular distance measurement data acquisition module; used to acquire the stellar angular distance measurement data information of Beidou satellites in three space-based orientation observation modes; the three space-based orientation observation modes include a staring measurement mode, a short-period round-robin measurement mode, and a long-period round-robin measurement mode; the stellar angular distance measurement data information includes a first-mode stellar angular distance measurement data set, a second-mode stellar angular distance measurement data set, and a third-mode stellar angular distance measurement data set; the stellar angular distance measurement data includes the relative right ascension and relative declination data between stars in the celestial coordinate system; A Ka-band inter-satellite link observation value acquisition module, used to perform inter-satellite observations using the Ka inter-satellite link to acquire Ka-band inter-satellite link observation values; An L-band satellite-ground link observation value acquisition module, used to perform L-band satellite-ground observations using Beidou system monitoring stations to acquire L-band satellite-ground link observation values; A satellite position parameter calculation module, used to construct a multi-dimensional observation matrix and perform solution processing based on the stellar angular distance measurement data information, Ka-band inter-satellite link observation values, and L-band satellite-ground link observation values to obtain satellite position parameters corresponding to the three space-based orientation observation modes; An observation mode determination module, used to perform comparison processing on the satellite position parameters corresponding to the three space-based orientation observation modes with the MGEX precise ephemeris as the comparison baseline to obtain the optimal observation mode.

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