A BDS satellite space signal availability evaluation method, system and electronic equipment

Abstract

The application provides a BDS satellite space signal availability evaluation method, system and electronic equipment, and the technical points are as follows: collecting all broadcast ephemeris data broadcasted in a limited time period of a BDS constellation; establishing a two-step method to detect orbit maneuver of IGSO satellites and GEO satellites of the BDS constellation, and calculating average fault interval time and average fault repair time of the orbit maneuver of the IGSO satellites and the GEO satellites; detecting space signal anomaly of BDS satellites, and calculating average fault interval time and average fault repair time of the space signal anomaly of the BDS satellites for IGSO satellites, GEO satellites and MEO satellites of the BDS constellation; and comprehensively establishing an availability comprehensive evaluation model of the space signal of the BDS satellites to evaluate and calculate the availability performance of the space signal of the BDS satellites. The application greatly improves the accuracy and reliability of the orbit maneuver detection of the BDS satellites, and provides a new method for BDS satellite space signal availability evaluation from the perspective of actual measurement data.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of performance evaluation of satellite navigation system, and more particularly relates to a BDS satellite space signal availability evaluation method and system and electronic equipment. BACKGROUND

[0002] As a national security and economic development infrastructure, satellite navigation system has become an important support link in the construction of information system of countries all over the world. With the continuous investment, construction and development of satellite navigation systems of various countries, better system performance is the competitiveness of each satellite navigation system. There are four performance indicators of satellite navigation system, which are accuracy, integrity, continuity and availability. Among them, availability is the percentage of time that the satellite navigation system can provide available navigation service in the service space, which reflects the cumulative statistics of time that can meet the performance of the navigation system, and is a key performance indicator for judging whether the navigation system can be the only or main navigation system in the field of high-precision and high-reliability application.

[0003] With the rapid construction and development of satellite navigation system and the gradual widening of its application field, the performance requirements of satellite navigation system in different fields are more diverse and extensive, especially in the application fields related to life safety such as airport precision approach and automatic driving. For example, during the approach and departure stages of the aircraft, incorrect navigation information will directly cause serious aviation accidents and pose a great threat to life safety. Therefore, compared with the accuracy requirement, the integrity, continuity and availability requirements of the system are equally important. Accuracy is no longer the only indicator for measuring the performance of satellite navigation system, and good integrity, continuity and availability are important guarantees for the safety and reliability of satellite navigation system.

[0004] When satellite navigation system provides extensive services, users are both users and testers of the system. The improvement and reduction of the performance of satellite navigation system will have a direct impact on the user end. Therefore, at each stage of the development of satellite navigation system, the performance of the system needs to be monitored and evaluated, the running state of the system needs to be monitored in real time, and whether the performance of the system can meet the original design requirements needs to be tested, so as to provide a scientific basis for the performance improvement of the system and promote the modernization process of satellite navigation system.

[0005] At present, relevant researches on performance evaluation of satellite navigation system have been carried out at home and abroad, but the research results are mainly for GPS system and less for BDS system. Moreover, for the performance evaluation of BDS system, especially the availability performance evaluation, various types of expected values are mainly used, and there is a lack of verification analysis of measured data, so that the credibility of the availability evaluation result of BDS system is low. SUMMARY

[0006] In order to solve the above technical problems, the application provides a BDS satellite space signal availability evaluation method, system and electronic equipment.

[0007] According to a first aspect of the application, a BDS satellite space signal availability evaluation method is provided, comprising:

[0008] Step 1: Collect all broadcast ephemeris data broadcasted by the BDS constellation within a limited time period;

[0009] Step 2: For the inclined geosynchronous orbit satellites and geosynchronous orbit satellites of the BDS constellation, establish a two-step method to detect the orbit maneuver of the IGSO satellites and GEO satellites, and calculate the average failure interval time and average failure repair time of the orbit maneuver of the IGSO satellites and GEO satellites;

[0010] Step 3: For the IGSO satellites, GEO satellites and MEO satellites of the BDS constellation, establish a BDS satellite space signal anomaly detection method based on precise ephemeris to detect the space signal anomaly of the BDS satellites, and calculate the average failure interval time and average failure repair time of the space signal anomaly of the BDS satellites, respectively;

[0011] Step 4: Integrate the orbit maneuver and the space signal anomaly, based on the obtained average failure interval time and average failure repair time of the orbit maneuver of the IGSO satellites and GEO satellites, and the average failure interval time and average failure repair time of the space signal anomaly of the BDS satellites, establish a BDS satellite space signal availability comprehensive evaluation model, and evaluate and calculate the BDS satellite space signal availability performance according to the availability comprehensive evaluation model.

[0012] On the basis of the above technical solution, the application can also be improved as follows.

[0013] Optionally, the establishment of the BDS satellite space signal availability comprehensive evaluation model is represented as:

[0014]

[0015]

[0016] In the formula, A1 is the availability of the IGSO satellites and GEO satellites of the BDS constellation, A2 is the availability of the MEO satellites of the BDS constellation, MTBF1 represents the average failure interval time of the orbit maneuver of the IGSO satellites and GEO satellites, MTTR1 represents the average failure repair time of the orbit maneuver of the IGSO satellites and GEO satellites, MTBF2 represents the average failure interval time of the space signal anomaly of the BDS satellites, and MTTR2 represents the average failure repair time of the space signal anomaly of the BDS satellites.

[0017] Optionally, in step 2, the establishing the orbit maneuver of the IGSO satellite and the GEO satellite in the two-step method includes orbit maneuver identification and orbit maneuver verification, and specifically includes the following sub-steps:

[0018] Step 2.1: Constructing a broadcast ephemeris time sequence of the IGSO satellite or the GEO satellite within a limited time period;

[0019] Step 2.2: Detecting the broadcast ephemeris time sequence of the IGSO satellite or the GEO satellite, marking a period when the satellite autonomous health identification in the broadcast ephemeris sequence is continuously ≥N ephemeris time, and recording it as t i ~t i+n , constructing a long semi-axis square root time sequence of the broadcast ephemeris in the t i ~t i+n period, eliminating the continuous long semi-axis square root time sequence, retaining the long semi-axis square root time sequence that jumps, and N≥4;

[0020] Step 2.3: For the broadcast ephemeris in the t i ~t i+n period obtained after orbit maneuver identification, using the broadcast ephemeris of SatH1=0 at t i-1 time to predict the satellite orbit in the t i ~t i+n period, marking it as “initial orbit”; using the broadcast ephemeris of SatH1=0 at t i+n+1 time to predict the satellite orbit in the t i ~t i+n period, marking it as “final orbit”; calculating the orbit difference and making the following judgment: if the satellite does not have an orbit maneuver, the “initial orbit” and the “final orbit” will coincide; if the satellite has an orbit maneuver, the “initial orbit” and the “final orbit” will have a km-level deviation;

[0021] Step 2.4: For any IGSO satellite or GEO satellite, statistics of all t i ~t i+n periods caused by orbit maneuver within one year, respectively calculating the average failure interval time and the average failure repair time of the IGSO satellite or the GEO satellite orbit maneuver.

[0022] Optionally, in step 2.4, the average failure interval time and the average failure repair time of the IGSO satellite or the GEO satellite orbit maneuver are respectively calculated as:

[0023]

[0024] In the formula, MTBF1 represents the average failure interval time of IGSO satellite and GEO satellite orbit maneuver; MTTR1 represents the average failure repair time of IGSO satellite and GEO satellite orbit maneuver; and m represents the number of time periods of orbit maneuver.

[0025] Optionally, in step 3, the method for detecting BDS satellite space signal anomaly based on precise ephemeris detects the BDS satellite space signal anomaly, and specifically includes the following sub-steps.

[0026] Step 3.1: Calculate the satellite orbit coordinates and clock error at intervals with the precise ephemeris by using the BDS satellite broadcast ephemeris; take the satellite orbit coordinates and clock error provided by the precise ephemeris as a reference to calculate the orbit error and clock error;

[0027] Step 3.2: Set the orbit error threshold and clock error threshold; if any of the errors does not meet the condition, determine the gross error data block and mark the space signal anomaly;

[0028] Step 3.3: Sort the broadcast ephemeris gross error data block of each BDS satellite identified according to the reference time of the satellite clock, merge into a group of space signal anomaly time sequences, and divide the space signal anomaly time sequences into a plurality of time periods according to the number of time periods, and mark as t i ~t i+n ;

[0029] Step 3.4: Count all ti~ti+n time periods caused by space signal anomaly of each BDS satellite within one year, and calculate the average failure interval time and average failure repair time of the BDS satellite space signal anomaly.

[0030] Optionally, in step 3.4, the average failure interval time and average failure repair time of the BDS satellite space signal anomaly are calculated as follows:

[0031]

[0032]

[0033] In the formula, MTBF2 represents the average failure interval time of the BDS satellite space signal anomaly; MTTR2 represents the average failure repair time of the BDS satellite space signal anomaly; and m represents the number of time periods of the space signal anomaly.

[0034] Optionally, the orbit error threshold is set as IGSO satellite and MEO satellite orbit error <10m, and GEO satellite orbit error <50m; and the clock error threshold is set as clock error <30ns.

[0035] According to the second aspect of the present application, a BDS satellite space signal availability evaluation system is provided, which comprises:

[0036] a data collection module, configured to collect all broadcast ephemeris data broadcast by BDS constellations within a limited time period;

[0037] a first calculation module, configured to establish a two-step method for detecting orbit maneuver of IGSO satellites and GEO satellites of the BDS constellations, and to calculate average fault interval time and average fault repair time of the orbit maneuver of the IGSO satellites and the GEO satellites;

[0038] a second calculation module, configured to establish a BDS satellite space signal anomaly detection method based on precise ephemeris for detecting space signal anomaly of the BDS satellites, and to calculate average fault interval time and average fault repair time of the space signal anomaly of the BDS satellites, respectively;

[0039] an availability comprehensive evaluation model establishment module, configured to comprehensively evaluate orbit maneuver and space signal anomaly, to establish a BDS satellite space signal availability comprehensive evaluation model based on the average fault interval time and the average fault repair time of the orbit maneuver of the IGSO satellites and the GEO satellites, and the average fault interval time and the average fault repair time of the space signal anomaly of the BDS satellites, and to evaluate and calculate BDS satellite space signal availability performance according to the availability comprehensive evaluation model.

[0040] According to a third aspect of the present application, an electronic device is provided, comprising a memory and a processor, the processor being configured to implement the steps of a BDS satellite space signal availability evaluation method when executing a computer program stored in the memory.

[0041] Technical effects and advantages of the present application:

[0042] The present application detects orbit maneuver of BDS IGSO satellites and GEO satellites based on a two-step method of orbit maneuver identification and orbit maneuver verification, detects space signal anomaly of the BDS satellites based on a BDS satellite space signal anomaly detection method based on precise ephemeris, then comprehensively evaluates orbit maneuver and space signal anomaly, establishes a BDS satellite space signal availability comprehensive evaluation model, evaluates and calculates BDS satellite space signal availability performance, and provides a new method for BDS satellite space signal availability evaluation from the perspective of actual measurement data.

[0043] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the written description and claims, and the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 A flowchart of a BDS satellite space signal availability assessment method provided in an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of the "track movement identification" flowchart in the "two-step method" provided in the embodiments of the present invention;

[0046] Figure 3 This is a schematic diagram of the "track maneuver verification" in the "two-step method" provided in the embodiments of the present invention;

[0047] Figure 4 The flowchart of the "BDS satellite space signal anomaly detection method based on precise ephemeris" provided in the embodiments of the present invention. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Understandably, given the deficiencies in the background technology, this invention proposes a BDS satellite space signal availability assessment method, please see... Figure 1 The evaluation method includes the following steps:

[0050] Step 1: Collect all broadcast ephemeris data broadcast within the BDS constellation's limited time period;

[0051] It should be noted that the Beidou Navigation Satellite System (BDS) constellation includes three types of orbits: geostationary Earth orbit (GEO), inclined geosynchronous orbit (IGSO), and medium Earth orbit (MEO).

[0052] In this embodiment, the time period is preferably one year.

[0053] Step 2: For the IGSO and GEO satellites of the BDS constellation, establish a "two-step method" to detect the orbital maneuvers of the IGSO and GEO satellites, and calculate the mean time between failures and the mean time to repair of failures for the orbital maneuvers of the IGSO and GEO satellites, denoted as MTBF1 and MTTR1.

[0054] See Figure 2 with Figure 3 The present application provides a "two-step method" for detecting IGSO satellite and GEO satellite orbit maneuver, which comprises the following steps:

[0055] Step 2.1: Constructing a time sequence of broadcast ephemeris of IGSO satellite (or GEO satellite) in one year;

[0056] Step 2.2: Orbit maneuver identification: detecting the time sequence of broadcast ephemeris of IGSO satellite (or GEO satellite), marking the period when SatH1 = 1 in the broadcast ephemeris sequence for more than 4 consecutive ephemeris time instants, and recording it as t i ~ t i+n Then, constructing the long semi-axis square root of the broadcast ephemeris in the period of t i ~ t i+n , eliminating the continuous sequence, and retaining the sequence with jumps;

[0057] Step 2.3: Orbit maneuver verification: using the broadcast ephemeris of SatH1 = 0 at t i ~ t i+n time to predict the satellite orbit in the period of t i-1 ~ t i , marking it as "initial orbit"; using the broadcast ephemeris of SatH1 = 0 at t i+n ~ t i+n+1 time to predict the satellite orbit in the period of t i ~ t i+n , marking it as "final orbit"; then, calculating the orbit difference and making the following judgment: if the satellite has not undergone orbit maneuver, the "initial orbit" and the "final orbit" will coincide; if the satellite has undergone orbit maneuver, there will be a km-level deviation between the "initial orbit" and the "final orbit".

[0058] Step 2.4: For any IGSO satellite (or GEO satellite), statistics the total t i ~ t i+n period caused by orbit maneuver in one year, and then calculate the average failure interval time MTBF1 and the average failure repair time MTTR1 of IGSO satellite (or GEO satellite) orbit maneuver according to the following formula respectively.

[0059]

[0060]

[0061] In the formula, m is the number of orbit maneuver periods.​

[0062] Step 3: For IGSO satellites, GEO satellites and MEO satellites of BDS constellation, a "BDS satellite space signal anomaly detection method based on precise ephemeris" is established to detect the space signal anomaly of BDS satellites, and the average failure interval time and the average failure repair time of the space signal anomaly of BDS satellites are calculated, denoted as MTBF2 and MTTR2 respectively.

[0063] See Figure 4 The "BDS satellite space signal anomaly detection method based on precise ephemeris" provided by the application detects the space signal anomaly of BDS satellites, comprising the following steps:

[0064] Step 3.1: Calculate the satellite orbit coordinates and clock error at equal intervals with the precise ephemeris and the broadcast ephemeris of BDS satellites, and calculate the orbit error and clock error with the satellite orbit coordinates and clock error provided by the precise ephemeris as reference.

[0065] Step 3.2: Set the orbit error threshold value: IGSO satellites and MEO satellites <10m, GEO satellites <50m; Set the clock error threshold value: clock error <30ns; If any of the errors does not meet the condition, it is determined that the gross error data block is marked as space signal anomaly;

[0066] Step 3.3: Sort the broadcast ephemeris gross error data block of each BDS satellite identified according to the reference time TOC of the satellite clock, merge it into a group of space signal anomaly time sequence, and divide the space signal anomaly time sequence into several time periods according to the number of time periods, denoted as t i ~t i+n .

[0067] Step 3.4: Statistics of all t i ~t i+n periods of each BDS satellite within one year due to space signal anomaly, then calculate the average failure interval time MTBF2 and the average failure repair time MTTR2 of the space signal anomaly of BDS satellites according to the following formula.

[0068]

[0069]

[0070] In the formula, m is the number of time periods of space signal anomaly.

[0071] Step 4: Comprehensive orbit maneuver and space signal anomaly, according to the acquired MTBF1 and MTTR1 and MTBF2 and MTTR2 values, establish the availability comprehensive evaluation model of BDS satellite space signal (as shown in formula (1) and formula 2), and evaluate and calculate the availability performance of BDS satellite space signal based on the availability comprehensive evaluation model.

[0072]

[0073]

[0074] In the formula, A1 is the availability of BDS constellation IGSO satellites and GEO satellites, and A2 is the availability of BDS constellation MEO satellites.

[0075] In summary, the embodiment of the application detects the orbit maneuver of IGSO satellites and GEO satellites in the Beidou satellite navigation system based on the "two-step method" of "orbit maneuver identification" and "orbit maneuver verification", detects the BDS satellite space signal anomaly by establishing a "BDS satellite space signal anomaly detection method based on precise ephemeris", then, establishes a comprehensive evaluation model of BDS satellite space signal availability by integrating the orbit maneuver and the space signal anomaly, and evaluates and calculates the BDS satellite space signal availability performance. The method greatly improves the accuracy and reliability of the BDS satellite orbit maneuver detection, and provides a new method for BDS satellite space signal availability evaluation from the perspective of actual measurement data.

[0076] According to the second aspect of the application, the embodiment of the application provides a BDS satellite space signal availability evaluation system, which comprises:

[0077] A data acquisition module is configured to acquire all broadcast ephemeris data broadcasted by the BDS constellation within a limited time period.

[0078] A first calculation module is configured to establish a "two-step method" to detect the orbit maneuver of IGSO satellites and GEO satellites of the BDS constellation, and to calculate the average failure interval time and the average failure repair time of the orbit maneuver of the IGSO satellites and the GEO satellites.

[0079] A second calculation module is configured to establish a "BDS satellite space signal anomaly detection method based on precise ephemeris" to detect the space signal anomaly of the BDS satellite for the IGSO satellites, the GEO satellites and the MEO satellites of the BDS constellation, and to calculate the average failure interval time and the average failure repair time of the space signal anomaly of the BDS satellite respectively.

[0080] An availability comprehensive evaluation model establishment module is configured to integrate the orbit maneuver and the space signal anomaly, to establish a comprehensive evaluation model of the availability of the BDS satellite space signal based on the average failure interval time and the average failure repair time of the orbit maneuver of the IGSO satellites and the GEO satellites, and the average failure interval time and the average failure repair time of the space signal anomaly of the BDS satellite, and to evaluate and calculate the availability performance of the BDS satellite space signal according to the comprehensive evaluation model of the availability.

[0081] It can be understood that the BDS satellite space signal availability evaluation system provided by the present application corresponds to the BDS satellite space signal availability evaluation method provided by the foregoing embodiments, and the related technical features of the BDS satellite space signal availability evaluation system can refer to the related technical features of the BDS satellite space signal availability evaluation method, which will not be repeated here.

[0082] According to the third application of the present application, an electronic device is provided, which comprises a memory, a processor, and a computer program stored in the memory and capable of running on the processor, and the processor implements the steps of the BDS satellite space signal availability evaluation method when executing the computer program.

[0083] According to the fourth application of the present application, a computer readable storage medium is provided, which stores a computer program, and the computer program implements the steps of the BDS satellite space signal availability evaluation method when executed by a processor.

[0084] It should be understood that parts not described in detail in the present specification are all prior art.

[0085] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all the preferred embodiments and all the changes and modifications falling within the scope of the present application.

[0086] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

[0087] Finally, it should be noted that: the above only describes the preferred embodiments of the present application and is not intended to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or equivalently replace some technical features, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for evaluating BDS satellite space signal availability, characterized in that, The evaluation method comprises the following steps: Step 1: collecting all broadcast ephemeris data broadcasted by BDS constellations within a limited time period; Step 2: establishing a two-step method for detecting orbit maneuvers of IGSO satellites and GEO satellites of the BDS constellation, and calculating the average failure interval time and the average failure repair time of the orbit maneuvers of the IGSO satellites and the GEO satellites; the establishment of the two-step method for detecting the orbit maneuvers of the IGSO satellites and the GEO satellites comprises "orbit maneuver identification" and "orbit maneuver verification", and comprises the following sub-steps: Step 2.1: constructing a broadcast ephemeris time sequence of the IGSO satellites or the GEO satellites within a limited time period; Step 2.2: Detect the IGSO satellite or GEO satellite broadcast ephemeris time sequence, mark the period when the satellite autonomous health identification in the broadcast ephemeris sequence is SatH1=1 for consecutive ≥N epochs, recorded as t i ~t i+n , construct the long semi-axis square root time sequence of the broadcast ephemeris in the period t i ~t i+n , eliminate the continuous long semi-axis square root time sequence, retain the long semi-axis square root time sequence with jump, N≥4; Step 2.3: For the t obtained after track maneuver identification i ~t i+n Broadcast ephemeris during time period, using t i-1 Broadcast ephemeris prediction t at time SatH1=0 i ~t i+n The satellite orbit for that period is labeled "initial orbit"; using t i+n+1 Broadcast ephemeris prediction t at time SatH1=0 i ~t i+n The satellite orbit for a given period is marked as the "final orbit". The orbital discrepancy is calculated and the following judgments are made: if the satellite does not undergo orbital maneuvers, the "initial orbit" and the "final orbit" will coincide; if the satellite undergoes orbital maneuvers, there will be a deviation of kilometers between the "initial orbit" and the "final orbit". Step 2.4: For any IGSO satellite or GEO satellite, count all ts caused by orbit maneuver in a year i i+n Step 2.5: Calculate the average failure interval time and the average failure recovery time of IGSO satellite or GEO satellite orbit maneuver, respectively.​ Step 3: establishing a BDS satellite space signal anomaly detection method based on precise ephemeris for detecting space signal anomalies of the BDS satellites, and calculating the average failure interval time and the average failure repair time of the space signal anomalies of the BDS satellites respectively; The establishment of the BDS satellite space signal anomaly detection method based on precise ephemeris for detecting the space signal anomalies of the BDS satellites comprises the following sub-steps: Step 3.1: calculating satellite orbit coordinates and clock errors at intervals of precise ephemeris by using the broadcast ephemeris of the BDS satellites; taking the satellite orbit coordinates and clock errors provided by the precise ephemeris as references, calculating orbit errors and clock error errors; Step 3.2: setting orbit error thresholds and clock error error thresholds; if any of the errors does not meet the conditions, determining a gross error data block and marking a space signal anomaly; Step 3.3: The broadcast ephemeris rough error data block of each BDS satellite after identification is sorted according to the reference time of the satellite clock, combined into a set of spatial signal anomaly time sequences, and divided into several time periods according to the number of time periods, denoted as t i ~t i+n ; Step 3.4: Statistics of all t i i+n period, the average failure interval time and the average failure recovery time of the BDS satellite space signal anomaly are calculated.​ Step 4: comprehensively evaluating orbit maneuvers and space signal anomalies, establishing a BDS satellite space signal availability comprehensive evaluation model based on the average failure interval time and the average failure repair time of the orbit maneuvers of the IGSO satellites and the GEO satellites, and the average failure interval time and the average failure repair time of the space signal anomalies of the BDS satellites, and evaluating and calculating the BDS satellite space signal availability performance according to the availability comprehensive evaluation model.

2. The method according to claim 1, wherein, The establishment of the BDS satellite space signal availability comprehensive evaluation model is represented as: In the formula, A1 is the availability of the IGSO satellites and the GEO satellites of the BDS constellation, A2 is the availability of the MEO satellites of the BDS constellation, MTBF1 represents the average failure interval time of the orbit maneuvers of the IGSO satellites and the GEO satellites, MTTR1 represents the average failure repair time of the orbit maneuvers of the IGSO satellites and the GEO satellites, MTBF2 represents the average failure interval time of the space signal anomalies of the BDS satellites, and MTTR2 represents the average failure repair time of the space signal anomalies of the BDS satellites. In step 2.4, the calculation of the average failure interval time and the average failure repair time of the orbit maneuvers of the IGSO satellites or the GEO satellites is represented as:

3. The method of claim 1, wherein, In the formula, MTBF1 represents the average failure interval time of the orbit maneuvers of the IGSO satellites and the GEO satellites, MTTR1 represents the average failure repair time of the orbit maneuvers of the IGSO satellites and the GEO satellites, and m represents the number of time periods of the orbit maneuvers. In the formula, MTBF1 represents the average failure interval time of the orbit maneuvers of the IGSO satellites and the GEO satellites, MTTR1 represents the average failure repair time of the orbit maneuvers of the IGSO satellites and the GEO satellites, and m represents the number of time periods of the orbit maneuvers. ​ 4. The method of claim 1, wherein, In step 3.4, the average fault interval time and the average fault repair time of the space signal anomaly of the BDS satellite are represented as: In the formula, MTBF2 represents the average fault interval time of the space signal anomaly of the BDS satellite; and MTTR2 represents the average fault repair time of the space signal anomaly of the BDS satellite. M represents the number of time periods of the space signal anomaly.

5. The method according to claim 4, wherein, The orbit error threshold is set as: the orbit error of the IGSO satellite and the MEO satellite < 10 m, and the orbit error of the GEO satellite < 50 m; and the clock error threshold is set as: the clock error < 30 ns.

6. A BDS satellite space signal availability evaluation system, characterized in that, Comprise: The data acquisition module is used for acquiring all broadcast ephemeris data broadcasted in a limited time period of the BDS constellation; The first calculation module is used for establishing a two-step method to detect the orbit maneuver of the IGSO satellite and the GEO satellite of the BDS constellation, and calculating the average fault interval time and the average fault repair time of the orbit maneuver of the IGSO satellite and the GEO satellite; the establishment of the two-step method to detect the orbit maneuver of the IGSO satellite and the GEO satellite comprises "orbit maneuver identification" and "orbit maneuver verification", and comprises the following sub-steps: Step 2.1: constructing a broadcast ephemeris time sequence in a limited time period of the IGSO satellite or the GEO satellite; Step 2.2: Detect the IGSO satellite or GEO satellite broadcast ephemeris time sequence, mark the period when the satellite autonomous health identification in the broadcast ephemeris sequence is SatH1=1 for consecutive ≥N epochs, recorded as t i ~t i+n , construct the long semi-axis square root time sequence of the broadcast ephemeris in the period t i ~t i+n , eliminate the continuous long semi-axis square root time sequence, retain the long semi-axis square root time sequence with jump, N≥4; Step 2.3: Identify t i ~t i+n Broadcast ephemeris for the time period, using t i-1 Broadcast ephemeris at time SatH1=0 to predict t i ~t i+n Satellite orbit for the time period, marked as "initial orbit"; using t i+n+1 Broadcast ephemeris at time SatH1=0 to predict t i ~t i+n Satellite orbit for the time period, marked as "final orbit"; calculate the orbit difference and make the following judgement: if no orbit maneuver has occurred for the satellite, the "initial orbit" and "final orbit" will coincide; if an orbit maneuver has occurred for the satellite, the "initial orbit" and "final orbit" will have a deviation of km order. Step 2.4: For any IGSO satellite or GEO satellite, count all ts caused by orbit maneuver in a year i ~t i+n Calculate the average failure interval time and the average failure recovery time of IGSO satellite or GEO satellite orbit maneuver, respectively. The second calculation module is used for establishing a BDS satellite space signal anomaly detection method based on precise ephemeris to detect the space signal anomaly of the BDS satellite, and calculating the average fault interval time and the average fault repair time of the space signal anomaly of the BDS satellite for the IGSO satellite, the GEO satellite and the MEO satellite of the BDS constellation; The establishment of the BDS satellite space signal anomaly detection method based on precise ephemeris comprises the following sub-steps: Step 3.1: calculating the satellite orbit coordinates and the clock error at intervals with the precise ephemeris by using the broadcast ephemeris of the BDS satellite; taking the satellite orbit coordinates and the clock error provided by the precise ephemeris as references, the orbit error and the clock error are calculated; Step 3.2: setting the orbit error threshold and the clock error threshold; if any one of the errors does not meet the condition, the gross error block is determined, and is marked as the space signal anomaly; Step 3.3: The broadcast ephemeris rough error data block of each BDS satellite after identification is sorted according to the reference time of the satellite clock, combined into a set of spatial signal anomaly time sequences, and divided into several time periods according to the number of time periods, denoted as t i ~t i+n ; Step 3.4: Statistics of all t i i+n periods of abnormal space signals of BDS satellites in a year, the average failure interval time and the average failure repair time of abnormal space signals of BDS satellites are calculated.​ The availability comprehensive evaluation model establishment module is used for comprehensively evaluating the orbit maneuver and the space signal anomaly, establishing a BDS satellite space signal availability comprehensive evaluation model based on the average fault interval time and the average fault repair time of the orbit maneuver of the IGSO satellite and the GEO satellite, and the average fault interval time and the average fault repair time of the space signal anomaly of the BDS satellite, and evaluating and calculating the BDS satellite space signal availability performance according to the availability comprehensive evaluation model.

7. The system for BDS satellite space signal availability evaluation according to claim 6, wherein, The establishment of the BDS satellite space signal availability comprehensive evaluation model is represented as: In the formula, A1 is the availability of BDS constellation IGSO satellites and GEO satellites, A2 is the availability of BDS constellation MEO satellites; MTBF1 represents the average failure interval time of IGSO satellites and GEO satellites orbit maneuvering; MTTR1 represents the average failure repair time of IGSO satellites and GEO satellites orbit maneuvering; MTBF2 represents the average failure interval time of BDS satellite space signal anomaly; MTTR2 represents the average failure repair time of BDS satellite space signal anomaly.

8. An electronic device, comprising: The computer program product comprises a memory and a processor, and the processor is used to execute the computer program stored in the memory to realize the steps of the BDS satellite space signal availability evaluation method according to any one of claims 1 to 5.

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