A method for continuously establishing a low-orbit satellite feeder link

Abstract

The present invention discloses a method for continuously establishing a low-orbit satellite feeder link, which belongs to the field of low-orbit satellite communication systems. It can autonomously generate control information such as equipment power on / off instructions, RF channel and antenna port switching instructions, antenna pointing angle calculation, route update reporting instructions, etc. according to parameters such as mission model, gateway station location, satellite trajectory, etc., and complete data flow guidance to realize satellite relay communication between two gateway stations. During the relay process, there is only a short period of time when the flow rate is reduced to 50% and there is no link interruption; considering that this method is based on dual circular polarization antennas, even if the flow rate is reduced to 50%, it is still the same as the traditional method. This configuration is suitable for various functional satellite platforms to meet the needs of large-capacity satellite-to-ground communications and rapid data backhaul.

Description

Technical Field

[0001] The invention relates to a method for continuously establishing a low-orbit satellite feeder link, and belongs to the field of low-orbit satellite communication systems. Background Art

[0002] In recent years, with the expansion of low-orbit satellite Internet application scenarios and the growth of large-scale data landing needs, considering the difficulties in deploying ground communication gateways outside my country and the limited transit time caused by the rapid movement of low-orbit satellites over the earth, how to make full use of satellite transit time and maximize communication capacity is one of the current research hotspots in the field of low-orbit satellite communications.

[0003] At present, the feed link payload of low-orbit communication satellites is usually equipped with a single set of high-power amplifiers, large-caliber mechanically rotatable antennas and other payload equipment to achieve high-speed data transmission. Due to the rapid movement of satellites to the ground, the visible time with fixed gateways is limited. Therefore, multiple gateways need to be deployed in the country to relay links with satellites to increase the satellite-to-ground communication time and communication capacity; however, the satellites currently in orbit have link interruptions during the relay process between two gateways, that is, the ground link is interrupted when leaving the original gateway until the link is re-established with the next gateway. During the entire interruption process, it is necessary to re-complete antenna pre-pointing, link synchronization, route update diffusion and other actions, which takes a long time; in particular, in order to reduce the impact of antenna rotation on the micro-vibration of satellites and other payloads, the antenna rotation rate is usually set very low, and the rotation range of low-orbit satellites is usually large, so the rotation of the antenna from the previous gateway position to the new gateway position will cause a long link interruption. Summary of the invention

[0004] The purpose of the present invention is to avoid the shortcomings of the above-mentioned background technology and propose a method for continuously establishing a low-orbit satellite feed link. The present invention is simple to implement. By configuring signal processing, two radio frequency channels and two sets of dual circularly polarized reflector antennas, the communication capacity can be doubled through circular polarization multiplexing. The purpose of the present invention is achieved through the following technical solutions:

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for continuously establishing a low-orbit satellite feeder link, specifically comprising the following steps:

[0007] Step 1: The satellite and the ground gateway station a establish a stable link to achieve two-way high-speed signal transmission; wherein, both sets of RF channels are matched to the same antenna, and the other antenna is in a dormant or waiting to be started state;

[0008] Step 2: The satellite calculates the location of the gateway station with longer link establishment time and more reliability in real time based on the mission model, the location of the ground gateway station and the real-time trajectory of the satellite stored in its signal processing module;

[0009] If the satellite and the ground gateway station b are visible for a longer time and the link is more stable, the satellite's signal processing module generates a command to control the dormant antenna to point to the ground gateway station b in advance, and the antenna enters the ready-to-use state from the dormant state;

[0010] Step 3: The signal processing module reports the route update indication to the ground network control center. After receiving the route update indication, the ground network control center completes the route update and diffusion, switches one of the link data to the intersatellite link transmission, generates instructions to control the RF channel port to switch to the antenna to be enabled, and performs signal synchronization and link monitoring.

[0011] Step 4: The signal processing module reports the link monitoring status and route update instructions between the satellite and the ground gateway to be entered to the ground network control center again, and the ground network control center updates and diffuses the route after perception;

[0012] Step 5: After the constellation routing is updated, the original landing data is switched to the newly established feeder link;

[0013] Step 6: The signal processing module generates instructions to control the original channel port to match the new link antenna, and re-signal to perform signal synchronization and link monitoring;

[0014] Step 7: After the new link is synchronized, the signal processing module reports the periodic link monitoring situation to the ground network control center, and the ground network control center updates and diffuses the route after sensing it.

[0015] Step 8: The communication link between the satellite and the ground gateway is restored to two links; the original inter-satellite communication data is landed or the newly added service data is landed;

[0016] Step 9: The satellite completes the relay between two ground gateway stations.

[0017] Furthermore, during the new link establishment process in step 3, the satellite-to-ground communication capacity is reduced to one link.

[0018] Furthermore, in step 1, two-way bidirectional signal transmission is achieved based on dual circular polarization antennas; subsequent single-way signals are transmitted through a multi-carrier method to improve satellite-to-ground communication capacity.

[0019] Furthermore, in step 3, two dual circular polarization antennas are configured for alternate use, and the antenna target pointing is completed before relaying, so as to avoid the antenna rotating over a large range for too long, which affects the satellite-to-ground communication time.

[0020] Furthermore, the signal processing module stores the mission model and the real-time working status of the satellite to complete real-time instruction generation, including controlling the RF channel electronic switch, realizing the configuration selection of the RF channel and the reflector antenna, reporting of route update indications and generating calculations of antenna target angles; at the same time, the latest routing table of the ground network control center is diffused throughout the entire network.

[0021] Furthermore, the signal processing module includes two modulation and demodulation units, and two sets of radio frequency channel modules and reflective surface antennas are configured for use as primary and backup; wherein the reflective surface antennas are used alternately.

[0022] Further, it is realized by a feeder link system, the feeder link system includes a signal processing module, two groups of radio frequency channel modules and two dual circular polarization reflector antennas;

[0023] Among them, the signal processing module is used to complete two-way signal modulation and demodulation, route detection and status reporting, and multi-port information exchange functions; the signal processing module generates RF channel and reflector antenna power on and off, pointing angle calculation, route update instructions, and RF channel port switching instructions based on the mission model, satellite attitude and position, and gateway location parameters stored in itself, and controls the antenna to complete rotation adjustment; at the same time, according to the mission planning and link establishment, the route update instruction report is completed, and data distribution is completed according to the latest route to achieve traffic balance adjustment of each port;

[0024] The RF channel module is used to complete signal frequency conversion, power amplification, port switching and integrated transceiver operation; the RF channel module completes port switching according to the instructions of the signal processing module; it also performs up-conversion and power amplification on the service signal output by the signal processing module, as well as low-noise amplification and down-conversion on the reflector antenna signal; the RF channel module includes a duplexer, which realizes the matching selection of the RF channel with different reflector antennas through port switching; the two RF modules are respectively connected to the left-hand circular polarization port and the right-hand circular polarization port of the two reflector antennas;

[0025] The dual circularly polarized reflector antenna includes an antenna rotation mechanism controller and a mechanically rotatable antenna; the antenna rotation mechanism controller completes pointing angle analysis and antenna driving according to the instructions of the signal processing module; the mechanically rotatable antenna points to the target area according to the driving parameters of the antenna rotation mechanism controller and completes the wireless transmission and reception of signals.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] 1. The present invention can realize two-way bidirectional signal transmission by adopting dual circular polarization antenna, which doubles the capacity of single circular polarization antenna. Subsequent single-channel signal can further improve the satellite-to-ground communication capacity through multi-carrier mode;

[0028] 2. The present invention can complete the real-time instruction generation according to the task storage task model and the real-time working status of the satellite, including controlling the RF channel electronic switch to realize the configuration selection of the RF channel and the reflector antenna, the reporting of the route update indication, the calculation of the antenna target angle generation, etc. Among them, the electronic switch switching time is usually in nanoseconds. At the same time, the latest routing table of the network controller is received and diffused throughout the network.

[0029] 3. The present invention configures two dual circular polarization antennas for use alternately, and completes the antenna target pointing before relaying, so as to avoid the antenna rotating for a long time over a large range, which affects the satellite-to-ground communication time; due to the limited rotation speed of the antenna and the large rotation range of the low-orbit satellite, this method can save the interruption time required for the entire antenna to point from bias to the initial target, effectively shortening the link interruption time. At the same time, the alternating use of antennas can further improve the reliability of the equipment and the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a schematic diagram of the implementation principle of a method for continuously establishing a feeder link for a low-orbit satellite. DETAILED DESCRIPTION

[0031] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings and examples.

[0032] During the on-orbit operation of the satellite, it autonomously analyzes and generates instructions to control the electronic switch according to the information such as the gateway parameters and the satellite trajectory to achieve the matching selection of the RF channel and the reflector antenna. When communicating stably with the fixed gateway, the two RF channels are matched to the same antenna to complete large-capacity communication. Before the relay, without affecting the existing communication capability, the signal processing module generates an antenna rotation instruction to control the other antenna to rotate in advance to the gateway to be entered, and then enters the switching process. During the switching process, the satellite-to-ground data diversion must be completed first, that is, 50% of the satellite-to-ground traffic is directed to the inter-satellite link. Secondly, the electronic switch of one of the RF channels is controlled to match the dormant antenna to complete the link establishment with the ground gateway. Thirdly, the traffic of the original link is directed to the newly established link. Finally, the RF channel of the original link is also switched to the new link antenna to complete the satellite-to-ground link establishment and provide satellite-to-ground data transmission capability. The satellite-to-ground communication capability is restored, that is, the satellite completes the relay between the gateways. During the relay process, the traffic is reduced to 50% for only a short period of time and there is no link interruption; considering that this method is based on dual circular polarization antennas, even if the traffic is reduced to 50%, the rate is still the same as the traditional method. This configuration is suitable for various functional satellite platforms and meets the needs of large-capacity satellite-to-ground communications and rapid data backhaul.

[0033] A low-orbit satellite feed link system comprises a signal processing module, two groups of radio frequency channel modules, and two dual circularly polarized reflector antennas.

[0034] The signal processing module mainly completes functions such as two-way signal modulation and demodulation, route detection and status reporting, and multi-port information exchange; the signal processing module generates instructions such as RF channel and reflector antenna power on and off, pointing angle calculation, route update indication, and RF channel port switching based on the mission model, satellite attitude and position, gateway station position and other parameters stored in itself, and controls the antenna to complete rotation adjustment; at the same time, it completes the route update indication reporting according to the mission planning and link establishment, completes data distribution according to the latest route, and realizes traffic balancing adjustment of each port.

[0035] The RF channel module mainly completes signal frequency conversion, power amplification, port switching, and integrated transceiver. The RF channel module completes port switching according to the instructions of the signal processing module, that is, it realizes the matching selection of the RF channel and the antenna. It also performs up-conversion and power amplification of the service signal output by the signal processing module, as well as low-noise amplification and down-conversion of the reflector antenna signal. The RF channel module contains a duplexer, which realizes the matching selection of the RF channel and different reflector antennas through port switching. The two RF modules are connected to the left-hand circular polarization port and the right-hand circular polarization port of the two reflector antennas respectively.

[0036] The dual circular polarization reflector antenna mainly includes an antenna rotation mechanism controller and a mechanically rotatable antenna. The antenna rotation mechanism controller completes the pointing angle analysis and antenna driving according to the instructions of the signal processing module; the mechanically rotatable antenna points to the target area according to the driving parameters of the antenna rotation mechanism controller and completes the wireless transmission and reception of signals.

[0037] During the stable communication between the satellite and the ground gateway, the signal processing module completes the modulation and demodulation, encoding and decoding of the two signals as well as the routing switching; the RF channel module completes the signal frequency conversion, amplification, transceiver duplex and port selection. Both channel ports can be independently switched to the reflector antenna a or the reflector antenna b, and the other antenna is in a dormant state or to be activated.

[0038] The satellite signal processing module determines whether there is a more stable and longer link based on the mission model, the location of the ground gateway, the orbital position of the satellite and other parameters; if so, the dormant antenna enters the working state, and adjusts the dormant antenna to point to the new gateway in advance while maintaining the existing communication capability; after the pointing is completed, the routing switching unit of the signal processing module diverts the data, coordinates one of the signal data to the neighboring satellite for transmission and switches the channel port to the antenna to be activated. The satellite exchanges information with the newly connected gateway, including signal synchronization, link detection and other tasks. The signal processing module monitors the latest transmission path and reports the latest route update and diffusion, and adjusts the original satellite-to-ground data to complete the satellite-to-ground communication according to the latest satellite-to-ground path.

[0039] After the new satellite-to-ground link is working normally, the original satellite-to-ground link can be disconnected, that is, the channel port switching is completed through instructions, and both signals are matched to the same antenna to complete signal interaction; after the routing is reconverged and updated, both channels can communicate with the satellite and the ground, and the communication capacity is restored, that is, the switching between the signal gateways is completed.

[0040] The following is combined with Figure 1 The present invention is further described with reference to the accompanying drawings and specific embodiments.

[0041] Reference Figure 1 This embodiment is implemented through a feeder link system, which includes a signal processing module, a radio frequency channel module a, a radio frequency channel module b, a dual circular polarization reflector antenna a, and a dual circular polarization reflector antenna b. Figure 1 This is a schematic diagram of a method for continuously establishing a low-orbit satellite feeder link according to the present invention. Figure 1 Connecting lines, in the figure, the dual circular polarization reflector antenna a and the dual circular polarization reflector antenna b are antenna a and antenna b respectively.

[0042] The workflow of a method for continuously establishing a low-orbit satellite feeder link is as follows:

[0043] During the stable communication between the satellite and the ground gateway, the signal processing module completes the modulation, demodulation, encoding and decoding of the two signals; the RF channel module completes the signal frequency conversion, amplification and port selection, and the two channel ports are switched to the dual circular polarization reflector antenna a or antenna b, and the other antenna is in a dormant state or a waiting state or a waiting state.

[0044] The satellite signal processing module determines whether there is a more stable and longer link based on the location of the ground gateway and the orbital position of the satellite. If so, the dormant antenna enters the working state and points to the new ground gateway. After the pointing is completed, the routing switching unit of the signal processing module will split the data and coordinate the data of one of the baseband processing units (baseband processing unit a or baseband processing unit b) to the neighboring satellite for transmission. The satellite exchanges information with the newly connected ground gateway, including signal synchronization, link detection and other tasks. The signal processing module monitors the latest transmission path and reports the latest route update and diffusion. The original satellite-to-ground data completes the communication according to the latest satellite-to-ground path.

[0045] After the new satellite-to-ground link is working, the original satellite-to-ground link can be disconnected, that is, the channel switching is completed through instructions; after the routing is reconverged and updated, both channels can communicate with the satellite and the ground, that is, the switching is completed.

[0046] The brief working principle of the present invention is as follows:

[0047] The signal processing module, RF channel module, and reflector antenna form the phased array antenna architecture. This device realizes satellite-to-ground multi-channel information transmission by configuring the signal processing module, two RF channel modules, and two pairs of dual circularly polarized reflector antennas; it realizes advance pointing and relay use of the target by configuring the dual circularly polarized reflector antenna a and the dual circularly polarized reflector antenna b; the signal processing module realizes the location of the available ground gateway by configuring the task storage unit, and the payload control unit selects a more stable gateway with a longer link establishment time through the task storage content and satellite orbit parameters, and generates real-time instructions to control the port selection matching of the RF channel and the antenna and the signal transmission path selection requirements. The RF channel module a and the RF channel module b are equipped with electronic switches to select the port output according to the task instructions, that is, independent matching selection with the antenna.

[0048] During the stable communication between the satellite and the ground gateway, the signal processing module completes the modulation, demodulation, encoding and decoding of the two signals; the RF channel module completes the signal frequency conversion, amplification, transceiver duplex and port selection. Both channel ports can be independently switched to the dual circular polarization reflector antenna a or antenna b, and the other antenna is in sleep state or to be activated.

[0049] The satellite signal processing module determines whether there is a more stable and longer link based on the location of the ground gateway and the orbital position of the satellite. If so, the dormant antenna enters the working state and points to the new gateway. After the pointing is completed, the routing switching unit of the signal processing module diverts the data and coordinates the data of one of the baseband processing units (baseband processing unit a or baseband processing unit b) to the neighboring satellite for transmission. The satellite exchanges information with the newly connected gateway, including signal synchronization, link detection and other tasks. The signal processing module monitors the latest transmission path and reports the latest route update and diffusion. The original satellite-to-ground data completes the communication according to the latest satellite-to-ground path.

[0050] After the new satellite-to-ground link is working, the original satellite-to-ground link can be disconnected, that is, the channel switching is completed through instructions; after the routing is reconverged and updated, both channels can communicate with the satellite and the ground, that is, the switching is completed. The switching process is as follows:

[0051] Step 1: The satellite and the ground gateway station b establish a stable link to achieve two-way high-speed signal transmission; the two sets of RF channels are matched to the same antenna, and the other antenna is in a dormant or waiting state.

[0052] Step 2: The satellite calculates the location of the gateway station with longer link establishment time and more reliability in real time based on the mission model, ground gateway station location, satellite real-time trajectory, etc. stored in the signal processing module;

[0053] If the satellite and the ground gateway b are visible for a longer time and the link is more stable, the satellite's signal processing module generates a command to control the dormant antenna to point to the gateway b in advance, and the antenna enters the ready-to-use state from the dormant state;

[0054] Step 3: After pre-pointing is completed, the signal processing module reports the route update instruction to the network control center, switches one of the channel data to the intersatellite link transmission, and autonomously generates instructions to control one of the RF channel ports to switch to the antenna to be enabled for signal synchronization and link monitoring. In this process, the satellite-to-ground communication capacity is reduced to one channel.

[0055] Step 4: After the synchronization of the new link is completed, the signal processing module reports the link monitoring status and route update instructions between the satellite and the ground gateway to be entered to the ground network control center again. After the ground network control center perceives it, it will update and diffuse the route again, which usually takes minutes.

[0056] Step 5: After the route is updated, the original landing data is switched to the newly established feeder link;

[0057] Step 6: After the data switching is completed, the signal processing module generates instructions to control the original channel to match the new link antenna, perform signal synchronization and link monitoring;

[0058] Step 7: After the synchronization of the new link is completed, the signal processing module reports the periodic link monitoring status to the network control center, and the network control center updates and diffuses the route after sensing it.

[0059] Step 8: After the route is updated, the communication link between the satellite and the ground gateway is restored to two links; the original inter-satellite communication data can be landed or the new business data can be landed.

[0060] Step 9: The satellite completes the relay between the two gateway stations.

[0061] The satellite decides whether to switch based on the parameters such as the on-orbit operation status and the stored gateway station location. Before switching, the dormant antenna pre-pointing is completed. After the pointing is completed, the signal processing module reports the disconnection status of the second satellite-to-ground transmission link and the inter-satellite port status to the network control center. The network control center completes the route update, that is, adjusts the data transmitted through the second satellite-to-ground link to the inter-satellite link for transmission, and switches the RF channel port 1a in the second satellite-to-ground link to another port 2a to match another antenna to be activated; after the second satellite-to-ground link is re-established, the signal processing module reports the periodically detected link status and the first satellite-to-ground link port (i.e., port 1a and port 2a) and the second satellite-to-ground link port (i.e., port 2a or port 2b) status to the network control center, and the first satellite-to-ground link data is adjusted to the second satellite-to-ground link for transmission. Then, the RF channel port 1b in the first satellite-to-ground link switches to port 2b, and the signal synchronization is re-performed; finally, the signal processing module reports the establishment status of the first satellite-to-ground link to the network control center, and can provide services after completing the route update, thus completing the whole switching process.

[0062] The entire switching process involves two forced routing updates and diffusions, and two instruction generation and executions; antenna pre-pointing is completed without affecting the existing communication capabilities. Especially considering factors such as the large rotation range and limited rotation speed of low-orbit satellites, this method greatly shortens the communication time caused by switching and effectively improves the satellite-to-ground communication capacity.

Claims

1. A method for continuously establishing a feeder link of a low-orbit satellite, wherein the method is implemented by a feeder link system, wherein the feeder link system includes a signal processing module, two groups of radio frequency channel modules and two dual circularly polarized reflector antennas; in, The signal processing module is used to complete two-way signal modulation and demodulation, route detection and status reporting, and multi-port information exchange functions; the signal processing module generates RF channel and reflector antenna power on / off, pointing angle calculation, route update instructions, and RF channel port switching instructions based on the mission model, satellite attitude and position, and gateway location parameters stored in itself, and controls the antenna to complete rotation adjustment; at the same time, the route update instruction report is completed according to the mission planning and link establishment status, and data distribution is completed according to the latest route to achieve traffic balance adjustment of each port; The RF channel module is used to complete signal frequency conversion, power amplification, port switching and integrated transceiver operation; the RF channel module completes port switching according to the instructions of the signal processing module; it also performs up-conversion and power amplification on the service signal output by the signal processing module, as well as low-noise amplification and down-conversion of the reflector antenna signal; the RF channel module includes a duplexer, which realizes the matching selection of the RF channel with different reflector antennas through port switching; the two RF modules are respectively connected to the left-hand circular polarization port and the right-hand circular polarization port of the two reflector antennas; The dual circularly polarized reflector antenna includes an antenna rotation mechanism controller and a mechanically rotatable antenna; the antenna rotation mechanism controller completes the pointing angle analysis and antenna driving according to the instructions of the signal processing module; the mechanically rotatable antenna points to the target area according to the driving parameters of the antenna rotation mechanism controller and completes the wireless transmission and reception of signals; It is characterized in that it specifically includes the following steps: Step 1: The satellite and the ground gateway station a establish a stable link to achieve two-way high-speed signal bidirectional transmission; wherein, both sets of RF channels are matched to the same antenna, and the other antenna is in a dormant or waiting to be started state; two-way bidirectional signal transmission is achieved based on dual circular polarization antennas; subsequent single-channel signals are used to increase the satellite-to-ground communication capacity through multi-carrier mode; Step 2: The satellite calculates the location of the gateway station with longer link establishment time and more reliability in real time based on the mission model, the location of the ground gateway station and the real-time trajectory of the satellite stored in its signal processing module; If the satellite and the ground gateway station b are visible for a longer time and the link is more stable, the satellite's signal processing module generates a command to control the dormant antenna to point to the ground gateway station b in advance, and the antenna enters the ready-to-use state from the dormant state; Step 3: The signal processing module reports the route update indication to the ground network control center. After receiving the route update indication, the ground network control center completes the route update and diffusion, switches one of the link data to the intersatellite link transmission, generates instructions to control the RF channel port to switch to the antenna to be enabled, and performs signal synchronization and link monitoring. Step 4: The signal processing module reports the link monitoring status and route update instructions between the satellite and the ground gateway to be entered to the ground network control center again, and the ground network control center updates and diffuses the route after perception; Step 5: After the constellation routing is updated, the original landing data is switched to the newly established feeder link; Step 6: The signal processing module generates instructions to control the original channel port to match the new link antenna, and re-signal to perform signal synchronization and link monitoring; Step 7: After the new link is synchronized, the signal processing module reports the periodic link monitoring situation to the ground network control center, and the ground network control center updates and diffuses the route after sensing it. Step 8: The communication link between the satellite and the ground gateway is restored to two links; the original inter-satellite communication data is landed or the newly added service data is landed; Step 9: The satellite completes the relay between two ground gateway stations.

2. A method for continuously establishing a low-orbit satellite feeder link according to claim 1, characterized in that: During the new link establishment process in step 3, the satellite-to-ground communication capacity is reduced to one link.

3. A method for continuously establishing a low-orbit satellite feeder link according to claim 1, characterized in that: In step 3, two dual circularly polarized antennas are configured for alternate use.

4. A method for continuously establishing a low-orbit satellite feeder link according to claim 1, characterized in that: The signal processing module stores the mission model and the real-time working status of the satellite to complete real-time instruction generation, including controlling the RF channel electronic switch, realizing the configuration selection of the RF channel and the reflector antenna, reporting the routing update indication and generating the antenna target angle calculation; at the same time, it receives the latest routing table from the ground network control center and spreads it throughout the network.

5. A method for continuously establishing a low-orbit satellite feeder link according to claim 1, characterized in that: The signal processing module includes two modulation and demodulation units, a radio frequency channel module, and two sets of reflective surface antennas, which are used as primary and backup. Among them, the reflective surface antennas are used alternately.

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