Time-difference-based detection method for quick maneuver of geosynchronous satellite

Abstract

The application discloses a time-difference-based synchronous orbit satellite fast maneuvering detection method, and aims at the problem of maneuvering detection of synchronous orbit satellites under a radio monitoring system. The difference between the time-difference measurement value of satellite signals arriving at two receiving stations and the theoretical value calculated by a predicted ephemeris can be approximately a linear function of satellite position error. The difference between two different time points is used as a test statistic to detect whether the satellite has maneuvered. The application greatly reduces the number of estimated parameters and the demand for observation arc length, and only needs two receiving stations to observe a short arc segment for several minutes to realize fast maneuvering detection of the synchronous orbit satellite, thereby reducing the system complexity and improving the timeliness of the system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of space measurement and control, and particularly relates to a time difference-based rapid maneuvering detection method for geosynchronous orbit satellites. BACKGROUND

[0002] Geosynchronous orbit satellites are an important part of space assets of various countries, and it is of great value and significance to rapidly and accurately detect the maneuvering of non-cooperative geosynchronous orbit satellites and master their movement situation. During the orbit maneuvering of non-cooperative satellites, the maneuvering time and the size of the maneuvering force generally cannot be accurately known in real time, and it will be very difficult to detect the maneuvering of the satellites by using a dynamic orbit determination method. In addition, the dynamic orbit determination method often needs a long observation arc, and its timeliness is difficult to meet the growing application demand, so it is urgent to explore a new maneuvering detection method for geosynchronous orbit satellites.

[0003] At present, the observation means for geosynchronous orbit satellites mainly include optical monitoring, radar detection and radio monitoring. Optical monitoring cannot be observed during the day due to the influence of sunlight, and can only be observed at night. Moreover, the observation time will also be affected by factors such as overcast, cloud, atmospheric glow and the like, the effective observation time is short, and all-weather and all-arc observation of the target satellite cannot be realized. The radar detection has very strong detection capability for medium and low orbit targets, but needs to actively emit detection signals, the observation point is easy to be exposed, and the action distance is limited, so it is not suitable for observation and orbit determination of high orbit and deep space targets. The radio monitoring realizes the positioning and orbit determination of geosynchronous orbit satellites by measuring the angle, range and time difference of the downlink signals transmitted by the satellites. It has the advantages of high concealment and all-weather monitoring, and is more suitable for the monitoring and discovery of geosynchronous orbit satellites than the other two means. SUMMARY

[0004] The purpose of the present application is to provide a time difference-based rapid maneuvering detection method for geosynchronous orbit satellites, which solves the problem of low timeliness in the existing maneuvering detection of non-cooperative geosynchronous orbit satellites.

[0005] The technical solution adopted by the present application is as follows: a time difference-based rapid maneuvering detection method for geosynchronous orbit satellites, comprising the following steps:

[0006] Step 1: correlating the downlink signals of the geosynchronous orbit satellites received by two receiving stations to obtain the time difference observation value r of the satellite to the two receiving stations at time t t ;

[0007] Step 2: determining the initial orbit of the target satellite, and then using the initial orbit of the satellite to predict the satellite ephemeris to the observation time t, and letting the predicted ephemeris at the observation time t be s t ;

[0008] Step 3: based on the predicted ephemeris s tand the time difference theoretical value r of the two receiving station positions at the observation time t c ;

[0009] Step 4, the time difference observation value r is obtained t and the time difference theoretical value r t c The difference Vr t is calculated, and the first-order Taylor expansion of the predicted ephemeris s t is carried out.

[0010] Step 5, the time difference observation value r t and the time difference theoretical value r t c The difference is further differentiated, and the differentiated residual is taken as the test statistic

[0011] Step 6, the detection threshold is determined by the 3σ criterion, when the test statistic Δ exceeds the detection threshold, that is It is determined that the satellite has a maneuver.

[0012] The characteristics of the present application are also,

[0013] The calculation formula of the time difference observation value r t in step 1 is:

[0014] r t = r t o + n t

[0015] In the formula, n t is the time difference random observation noise; r t o is the real time difference of the satellite to the two receiving stations at t time, which is expressed as:

[0016]

[0017] In the formula, c1 and c2 are the coordinates of the two receiving stations in the geocentric system, is the position coordinate of the satellite.

[0018] In step 2, the initial orbit of the target satellite is determined by using historical observation data.

[0019] In step 2, the initial orbit of the target satellite is determined by downloading TLE root number from the Internet.

[0020] The calculation formula of the time difference theoretical value r t c in step 3 is:

[0021] r t c||c2-s t ||c1-s t ||

[0022] wherein c1 and c2 are the coordinates of the two receiving stations in the geocentric system respectively.

[0023] Vr in step 4 t is calculated by the formula:

[0024]

[0025] wherein (·) T represents the matrix transposition operation, Vs t is the ephemeris error, n t is the time difference random observation noise.

[0026] The calculation formula of the test statistic Δ in step 5 is:

[0027]

[0028] In step 6, assuming that the observation noises at the time instants t1 and t2 and are both zero-mean Gaussian noises with variances , then is a zero-mean Gaussian noise with variance .

[0029] The synchronous orbit satellite rapid maneuver detection method based on time difference has the advantages that, unlike the traditional dynamic method which firstly performs orbit determination on the satellite and then determines whether the satellite has maneuvered, the synchronous orbit satellite rapid maneuver detection method based on time difference determines whether the satellite has maneuvered by observing the influence of the satellite maneuver on the time difference, greatly reduces the number of to-be-estimated parameters and the requirement for the observation arc length, and only needs two receiving stations to observe for several minutes of short arc segment to realize the rapid maneuver detection of the synchronous orbit satellite, thereby reducing the system complexity and improving the timeliness of the system. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a flowchart of the synchronous orbit satellite rapid maneuver detection method based on time difference of the application;

[0031] Figure 2 is a schematic diagram of the change of the test statistic with time in the synchronous orbit satellite rapid maneuver detection method based on time difference of the application. DETAILED DESCRIPTION

[0032] The application will be described in detail below in combination with the drawings and specific embodiments.

[0033] Embodiment 1

[0034] This invention provides a rapid maneuver detection method for geostationary orbit satellites based on time difference. Addressing the maneuver detection problem of geostationary orbit satellites under a radio monitoring system, it utilizes the property that the residual difference between the measured time difference of satellite signals arriving at two receiving stations and the theoretical value calculated from the predicted ephemeris can be approximated as a linear function of the satellite's position error. The residual difference between two different times is used as a test statistic to detect whether the satellite has maneuvered. Rapid maneuver detection of geostationary orbit satellites can be achieved with only two receiving stations performing short-segment observations.

[0035] Through the above implementation steps, rapid detection of geostationary orbit satellite maneuvers based on dual-station time difference observation data can be achieved. The observation data required for maneuver detection usually only takes a few minutes, which reduces the complexity of the system while improving the timeliness of the system.

[0036] Example 2

[0037] This invention provides a method for rapid maneuver detection of geostationary orbit satellites based on time difference, such as... Figure 1 As shown, it includes the following steps:

[0038] 1) Perform correlation processing on the downlink signals from the geostationary satellite received by the two receiving stations, and calculate the time difference r between the satellite and the two receiving stations at time t. t Considering the existence of random observation errors, let r t =r t o +n t r t o Let n be the true time difference between the satellite and the two receiving stations at time t. t For time zone random observation noise, based on geometric relationships we have c1 and c2 are the coordinates of the two receiving stations in the geocentric system, respectively. These are the satellite's position coordinates.

[0039] 2) Initial orbit determination of the target satellite is performed using historical observation data, and then the satellite ephemeris is predicted to the observation time using the initial orbit. The predicted ephemeris at time t is s. t .

[0040] 3) Calculate the theoretical time difference r for the observation time based on the predicted ephemeris and the location of the receiving station. t c =||c2-s t ||-||c1-s t ||.

[0041] 4) Calculate the difference between the observed and theoretical time difference values ​​and perform a first-order Taylor expansion at the predicted ephemeris. Considering that geostationary satellites move relatively slowly relative to the Earth, in a short period of time The difference between the observation value and the theoretical value of the time difference of the two receiving stations is a linear function of the ephemeris error Vs t .

[0042] 5) Using the difference between the observation value and the theoretical value of the time difference of the two receiving stations, which is a linear function of the ephemeris error, the difference between the observation value and the theoretical value of the time difference at two different times t1 and t2 is further differentiated, and the differentiated residual error is taken as a test statistic and When the satellite does not maneuver in the time period from t1 to t2, the ephemeris error of the predicted ephemeris can also be considered to be approximately constant in a short time, that is, Therefore, If there is a maneuver in the time period from t1 to t2, Therefore, Therefore, Δ can be taken as a test statistic to determine whether the satellite is maneuvered.

[0043] 6) The variance of the random error of the statistical time difference measurement Assuming that the observation noise and are Gaussian noise with zero mean and variance , then is Gaussian noise with zero mean and variance . The detection threshold is determined by the 3σ criterion, and when the test statistic exceeds the detection threshold, that is, then it is determined that the satellite is maneuvered.

[0044] Embodiment 3

[0045] The present application provides a time difference-based synchronous orbit satellite rapid maneuver detection method. In embodiment 2, when the target satellite is determined, there is no historical observation data, and TLE root number can also be downloaded from the Internet instead.

[0046] Embodiment 4

[0047] The data used is the fifth large orbit transfer process of a certain synchronous orbit satellite, the position coordinates of the two receiving stations in the earth-fixed coordinate system are s1 and s2 respectively, the time difference random observation noise σ r = 1 m, the differentiated time interval t2-t1 = 5 min, the satellite starts to maneuver at the real ignition time 877.8 s, and in order to facilitate the description, the ephemeris and time difference at the four typical time points shown in Table 1 in the observation data are taken to illustrate the implementation steps of the present application.

[0048] Table 1 ephemeris and time difference of observation data at typical time points

[0049]

[0050] ​1) Correlate the received downlink signals of the two receiving stations to obtain the time difference r of the satellite to the two receiving stations at time t t .

[0051] 2) Use the historical observation data to determine the initial orbit of the target satellite, and then use the satellite initial orbit to predict the satellite ephemeris to the observation time, so that the predicted ephemeris at time t is s t .

[0052] 3) Calculate the theoretical value of the time difference r at the observation time using the predicted ephemeris and the positions of the receiving stations t c =||c2-s t ||-||c1-s t ||, then the theoretical time differences at 1s, 301s, 801s and 1101s are 3313017.1ns, 3312445.9ns, 3311535.9ns and 3311015.0ns respectively.

[0053] 4) Calculate the difference Vr between the observed value and the theoretical value of the time difference t , the differences between the observed value and the theoretical value of the time difference at 1s, 301s, 801s and 1101s are -166.3ns, -173.5ns, -180.5ns and -161.7ns respectively.

[0054] 5) As shown in Figure 2 , construct the test statistic to determine the difference time interval t2-t1=5min, if t1=1s, t2=301s, then the test statistic Δ=7.2ns;

[0055] 6) Use the 3σ criterion to determine the detection threshold Obviously, if t1=1s, t2=301s, Δ=7.2ns<14.1ns, it is determined that the satellite has not maneuvered.

[0056] Example 5

[0057] In Example 4, if t1=801s, t2=1101s, then the test statistic Δ is 18.5ns, which is greater than the detection threshold 14.1ns, so it is determined that the satellite has maneuvered.

[0058] Example 6

[0059] In Example 4, if there is no historical observation data for the initial orbit determination of the target satellite, the TLE root number can also be downloaded from the Internet instead.

Claims

1. A method for rapid maneuver detection of geostationary orbit satellites based on time difference, characterized in that, Includes the following steps: Step 1: Perform correlation processing on the downlink signals received by the geostationary satellite from the two receiving stations, and calculate the observed time difference r between the satellite and the two receiving stations at time t. t ; Step 2: Determine the initial orbit of the target satellite, and then use the initial orbit to predict the satellite ephemeris to the observation time t. Let the predicted ephemeris at observation time t be s. t ; Step 3: Based on the predicted ephemeris s t The theoretical time difference r at the observation time was calculated from the positions of the two receiving stations. t c ; Step 4: Calculate the observed time difference r t and the theoretical value of time difference r t c The difference Vr t And in the predicted ephemeris t First-order Taylor expansion; Step 5: Calculate the time difference r between two different times t1 and t2. t and the theoretical value of time difference r t c The difference is further differencing, and the residuals of the difference are used as the test statistic. Step 6: Determine the detection threshold using the 3σ criterion. When the test statistic Δ exceeds the detection threshold, i.e. Then it is determined that the satellite has maneuvered.

2. The method for rapid maneuver detection of geostationary orbit satellites based on time difference as described in claim 1, characterized in that, The time difference observation value r in step 1 t The calculation formula is: r t ＝r t o +n t In the formula, n t For time difference random observation noise; r t o Let t be the true time difference between the satellite and the two receiving stations, expressed as: In the formula, c1 and c2 are the coordinates of the two receiving stations in the geocentric system, respectively. These are the satellite's position coordinates.

3. The method for rapid maneuver detection of geostationary orbit satellites based on time difference as described in claim 1, characterized in that, In step 2, historical observation data is used to determine the initial orbit of the target satellite.

4. The method for rapid maneuver detection of geostationary orbit satellites based on time difference as described in claim 1, characterized in that, In step 2, the TLE elements are downloaded from the Internet to determine the initial orbit of the target satellite.

5. The method for rapid maneuver detection of geostationary orbit satellites based on time difference as described in claim 1, characterized in that, In step 3, the theoretical time difference value r t c The calculation formula is: r t c =||c2-s t ||-||c1-s t || In the formula, c1 and c2 are the coordinates of the two receiving stations in the geocentric system, respectively.

6. The method for rapid maneuver detection of geostationary orbit satellites based on time difference as described in claim 5, characterized in that, In step 4, Vr t The calculation formula is: In the formula, (·) T Vs represents the matrix transpose operation. t For ephemeris error, n t This is random observation noise due to time difference.

7. The method for rapid maneuver detection of geostationary orbit satellites based on time difference as described in claim 6, characterized in that, The formula for calculating the test statistic Δ in step 5 is as follows:

8. The method for rapid maneuver detection of geostationary orbit satellites based on time difference as described in claim 7, characterized in that, In step 6, the observation noise at times t1 and t2 is assumed. and All have zero mean and variance. Gaussian noise, then With zero mean and variance Gaussian noise.

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