A method for continuously establishing inter-satellite links to support orbital maneuvers of BeiDou-3 satellites

Abstract

The present invention discloses a method for continuously establishing an intersatellite link supporting the orbital maneuver of the BeiDou-3 satellite. The method uses the post-control theoretical orbit to assist in link building, so that the intersatellite link can operate stably and reliably. First, the intersatellite link topology routing of the satellite is planned, and an intersatellite link building plan is formulated. Then, before the orbital maneuver, two sets of satellite almanac parameters for the entire network are generated and the almanac parameters are added to the satellite. Then, the almanac link building is immediately enabled, and finally the orbital maneuver is implemented, so that the intersatellite link remains continuous. The method for continuously establishing an intersatellite link of the present invention is completely based on the satellite design state, and the processing flow can be automated. It can improve the intersatellite link of the orbital maneuvering satellite from being interrupted for K hours to being continuously uninterrupted throughout the whole process, and provides a technical guarantee for improving the service availability of the navigation system.

Description

Technical Field

[0001] The invention belongs to the technical field of satellite navigation and relates to a method for continuously establishing an inter-satellite link supporting orbital maneuvers of a BeiDou-3 satellite. Background Art

[0002] The BeiDou-3 satellite system is a navigation satellite system independently developed by my country. It has the function of providing navigation positioning and timing services to global users. BeiDou-3 satellites are equipped with intersatellite link terminals to realize the measurement and communication functions between satellites and between satellites and the ground. Intersatellite links are an important way to monitor the status and upload data of all satellites in the constellation, and it is also the only way to manage overseas satellites in real time. Satellites are affected by orbital perturbations and need to perform orbital maneuvers regularly to maintain the navigation constellation configuration. In addition, there are multiple BeiDou GEO satellites in the same position, and the frequency of orbital maneuvers is higher than that of IGSO and MEO orbital satellites. Changes in satellite orbital parameters can easily cause interruptions in intersatellite links. At present, in order to ensure the smooth intersatellite communication network, the processing method is to set the controlled satellite to an isolated state in advance during intersatellite link planning. The controlled satellite uses the satellite-to-ground S / L link for communication, and the intersatellite communication links of other satellites do not pass through the controlled satellite. About K hours (more than 1 day) after control, the ground obtains the new orbital parameters of the controlled satellite and then restores the intersatellite link network of the isolated satellite. The above method makes the satellite unable to participate in constellation link building for a long time after orbital maneuvers, affecting inter-satellite communication and lacking the data source of inter-satellite measurement, which has an adverse effect on the precise orbit determination of the satellite.

[0003] The existing Chinese patent "A method for establishing an intersatellite link in a Beidou navigation system" (Announcement No.: CN106597475B, Announcement Date: 20170426) discusses the establishment of an intersatellite link by fault information transmission in the case of a satellite failure in the Beidou navigation constellation. Since the method proposed in the patent requires changing the design status of the satellite, it is not applicable to situations where the technical status of the in-orbit satellites of the navigation constellation has been solidified. Summary of the invention

[0004] The purpose of the present invention is to provide a method for continuously establishing inter-satellite links that supports orbital maneuvers of BeiDou-3 satellites, which can enable the capture of inter-satellite link signals of the entire satellite network to be unaffected by orbital maneuvers, and ultimately improve the availability of satellite navigation services.

[0005] The technical solution adopted by the present invention is a method for continuously establishing an inter-satellite link supporting the orbital maneuvering of the BeiDou-3 satellite, which uses the post-control theoretical orbit to assist in link establishment, so that the inter-satellite link can operate stably and reliably, including the following steps:

[0006] Step 1. The ground control center plans the inter-satellite link topology routing of the BeiDou-3 satellite and formulates an inter-satellite link establishment plan;

[0007] Step 2. M hours before the controlled satellite orbits maneuver, the ground control center generates two sets of satellite almanac parameters for the entire network, I and II. The almanac parameters representing the orbit of the controlled satellite are generated according to the theoretical orbit after control, and the almanac parameters representing the orbits of other satellites are generated according to their actual measured orbits;

[0008] Step 3. N minutes before the orbital maneuver, the ground control center will record the almanac parameters of all satellites in the network one by one and immediately start the almanac link establishment;

[0009] Step 4. The controlled satellite establishes a link according to the almanac activated in step 3 and starts orbital maneuvers, and the intersatellite link remains continuous;

[0010] Step 5. About K hours after the satellite maneuver, the ground control center determines the satellite's true orbit, generates an almanac for the entire network based on it, and updates it uniformly to all satellites in the network.

[0011] In step 1, when the ground control center formulates the intersatellite link establishment plan, there is no need to deal with the satellites to be controlled specially. All satellites can be considered as available satellites and planned normally. Satellites in the entire network will operate normally according to the planning results.

[0012] In step 2, the reference time of the almanac of group I is the orbital maneuvering time, and the reference time of the almanac of group II is set to be 7 days later than the reference time of the almanac of group A by default.

[0013] In step 3, since it takes a certain amount of time to complete the full network injection, the time at which each satellite receives and executes it cannot be completely consistent. Based on the evaluation of the change in the satellite orbit maneuver, the almanac of the satellite's post-maneuver orbit is activated N minutes before the maneuver. The position error and velocity error are much smaller than the capture error range of the intersatellite link, which can ensure that the link is uninterrupted.

[0014] In step 4, the orbital maneuver is normally implemented, and the actual orbit of the controlled satellite will change within K hours. The ground control center monitors the link establishment status of the entire network. The satellites of the entire network use the pre-annotated theoretical orbit almanac after control. Although it is not completely consistent with the actual orbit, the error between the two is much smaller than the signal capture range, and even smaller than the error between the orbit before control and the actual orbit after control, so the intersatellite link can remain continuous.

[0015] In step 5, about K hours after the maneuver, the ground control center determines the actual orbit of the controlled satellite, uses the actual orbit to generate the almanac of the entire network, and uniformly updates it to all satellites in the network. The inter-satellite link management thereafter will be carried out using conventional management methods, so that the inter-satellite link will smoothly transition from the orbital maneuver to the completion of the new orbit determination without obvious interruption.

[0016] The beneficial effects of the present invention are as follows: the method proposed in the present invention is completely based on the satellite design status, the processing flow can be automated, and the inter-satellite link of the orbital mobile satellite can be improved from an interruption of K hours to full continuity, providing technical guarantee for improving the availability of navigation system services. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A flow chart of an inter-satellite link management method under a satellite orbit maneuvering condition for a method for continuously establishing an inter-satellite link supporting the orbit maneuvering of a BeiDou-3 satellite according to the present invention;

[0018] Figure 2 The present invention discloses a basic structure of almanac parameters for a method for continuously establishing an inter-satellite link that supports orbital maneuvers of a BeiDou-3 satellite. DETAILED DESCRIPTION

[0019] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] The invention discloses a method for continuously establishing an inter-satellite link supporting the orbital maneuvering of BeiDou-3 satellites, which utilizes the post-control theoretical orbit to assist in link establishment, so that the inter-satellite link can operate stably and reliably.

[0021] When BeiDou-3 GEO satellites need to perform orbit control to maintain their position in the geosynchronous belt, or IGSO and MEO satellites need to perform orbit change operations to maintain their constellation configuration, the orbital parameters of the satellites will change before and after the orbital maneuvers, and the true orbital parameters cannot be determined within a few hours after the orbital change. The almanac originally used to establish the intersatellite link will not match the true orbit, and as time goes by, the error accumulation to a certain extent will cause the intersatellite link to be interrupted.

[0022] The satellite in orbital maneuver is Satellite A, and the control time is 13:00 on a certain Saturday. In order to keep the intersatellite link uninterrupted, the disposal implementation process refers to Figure 1 , including the following steps:

[0023] 1. The ground control center normally formulates the intersatellite link establishment plan. There is no need to deal with the satellites to be controlled specially. All satellites are considered as available satellites and can be planned normally. The ground will note the link establishment planning results to the satellite, and the satellite will automatically execute on time.

[0024] 2. Before the orbital maneuver of satellite A, the ground control center will calculate the orbital parameters of the control target and generate two sets of satellite almanac parameters for the entire network, I and II. Figure 2 The almanac parameters of satellite A are generated based on the orbital parameters of the control target, and the almanac parameters of other satellites are generated by fitting the actual orbit. The timing of generating the almanac can be flexibly selected, and the first M hours of control is appropriate. The reference time of the almanac of Group I is the orbital maneuvering time, that is, 13:00 on Saturday, and the reference time of Group II is a certain time of the next week.

[0025] 3. The ground control center will record the generated almanac to all satellites in the network one by one, and immediately use the almanac to establish the link. The timing of recording the almanac can be from 2 hours before the maneuver of satellite A to 1 hour after the maneuver, preferably N minutes before the maneuver. According to the evaluation of the change in the satellite orbit maneuver, the position error and velocity error of the almanac of the post-control orbit are much smaller than the capture error range of the inter-satellite link before the maneuver, which can ensure the continuity of the link.

[0026] 4. The ground control center performs normal orbital maneuvers on satellite A, and the actual orbit of the controlled satellite will change. Within K hours, the entire network uses the pre-annotated theoretical orbit almanac after control to establish the link. Although it is not completely consistent with the actual orbit, the error between the two is much smaller than the signal capture range, and even smaller than the error between the orbit before control and the actual orbit after control, so the intersatellite link can remain continuous.

[0027] 5. About K hours after satellite A maneuvers, the ground control center determines the true orbit of satellite A, generates an almanac for the entire network based on it, and updates it uniformly to all satellites in the network. The position and velocity errors of the inter-satellite link are further reduced, and the inter-satellite link will be able to continue to operate stably.

Claims

1. A method for continuously establishing intersatellite links supporting orbital maneuvers of BeiDou-3 satellites, using the post-control theoretical orbit to assist in link establishment, so that the intersatellite links can operate stably and reliably, characterized in that: The steps include: Step 1. The ground control center plans the inter-satellite link topology routing of the BeiDou-3 satellite; Step 2. M hours before the controlled satellite performs orbital maneuvers, the ground control center generates two sets of satellite almanac parameters for the entire network, I and II; The almanac parameters characterizing the orbit of the controlled satellite are generated based on the theoretical orbit after control, and the almanac parameters characterizing the orbits of other satellites are generated based on their measured orbits; Step 3. N minutes before the orbital maneuver, the ground control center will note the almanac parameters generated in step 2 to all satellites in the network one by one, and immediately enable the almanac link establishment; The specific steps of almanac link establishment are as follows: the satellite will use the almanac parameters to point to the link establishment object and capture the intersatellite signal to complete the link establishment; Step 4. The controlled satellite establishes a link according to the almanac activated in step 3 and starts orbital maneuvers, thereby maintaining a continuous intersatellite link; Step 5. K hours after the satellite maneuver, the ground control center re-measures the satellite's true orbit, generates a network-wide almanac based on it, and uniformly updates it to all satellites in the network.

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