A satellite-to-ground spread spectrum communication method under high dynamic conditions

Abstract

The present invention discloses a satellite-to-ground spread spectrum communication method under high dynamic conditions, wherein a satellite is equipped with a high dynamic spread spectrum communication payload, and a high-speed aircraft is equipped with a high dynamic spread spectrum communication terminal. The method of the present invention adopts a satellite-to-ground integrated design, wherein a periodic spread spectrum signal is used for downlink, and the dynamics of the downlink signal is corrected by using the motion changes within the period; a burst spread spectrum signal is used for uplink, and a low signal-to-noise ratio parallel algorithm is used to ensure reliable reception of the uplink signal. The present invention overcomes the large frequency deviation and frequency deviation change rate introduced by the random motion of the high-speed aircraft, and has low performance requirements for the high dynamic spread spectrum communication terminal, thereby ensuring stable and reliable communication between the satellite and the high-speed aircraft.

Description

Technical Field

[0001] The invention belongs to the technical field of communication, and in particular relates to a satellite-to-ground spread spectrum communication method under high dynamic conditions. Background Art

[0002] With the development of aerospace technology, satellite communication has become an indispensable means of communication in modern society. It has the advantages of long communication distance, wide coverage, large capacity, convenient multi-address connection, no geographical restrictions and flexibility, and has been widely used in the communication field.

[0003] Although satellite communication systems have incomparable unique advantages compared to other information transmission methods, satellite-to-ground communications face serious threats in the complex electromagnetic environment. This requires that satellite-to-ground communication systems must adopt communication systems such as spread spectrum and frequency hopping.

[0004] With the rapid increase in the demand for satellite communications from high-speed aircraft, represented by airplanes, and the increasing requirements for high reliability and rapid response capabilities, it is necessary to establish direct communications between satellites and high-speed aircraft. The use of high-orbit satellites can easily meet the above communication needs of high-speed aircraft. Due to the high-speed and random motion between high-speed aircraft and satellites, the Doppler effect will occur, resulting in very high frequency deviation and frequency deviation change rate dynamics in the satellite-to-ground communication link, which in turn affects the communication performance. Under such high-dynamic conditions, it is difficult for general communication systems to establish stable and reliable communication links.

[0005] Therefore, it is particularly necessary to study a satellite-to-ground communication method that can adapt to high dynamics. Summary of the invention

[0006] In order to overcome the deficiencies of the prior art, the present invention provides a satellite-to-ground spread spectrum communication method under high dynamic conditions, wherein the satellite is equipped with a high dynamic spread spectrum communication payload, and the high-speed aircraft is equipped with a high dynamic spread spectrum communication terminal. The method of the present invention adopts a satellite-to-ground integrated design, wherein a periodic spread spectrum signal is used for the downlink, and the motion changes within the period are used to correct the dynamics of the downlink signal; a burst spread spectrum signal is used for the uplink, and a low signal-to-noise ratio parallel algorithm is used to ensure reliable reception of the uplink signal. The present invention overcomes the large frequency deviation and frequency deviation change rate introduced by the random motion of the high-speed aircraft, and has low performance requirements for the high dynamic spread spectrum communication terminal, thereby ensuring stable and reliable communication between the satellite and the high-speed aircraft.

[0007] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0008] Step 1: Construct a satellite-to-ground spread spectrum communication system under high dynamic conditions, which consists of two parts: a satellite and a high-speed aircraft; the satellite can communicate data with multiple high-speed aircraft, including transmitting downlink signals to the high-speed aircraft, and receiving and processing uplink signals from the high-speed aircraft;

[0009] Step 2: Set the downlink signal of the satellite-to-ground spread spectrum communication system;

[0010] Step 2-1: The downlink signal adopts the direct sequence spread spectrum system, and the signal carrying information is spread before transmission;

[0011] Step 2-2: The physical frame of the downlink signal consists of a frame header, a broadcast data area and a service data area, wherein the frame header contains a synchronization word, a unique word and a rate indicator word; the synchronization word of the frame header is used for synchronous capture of the spread spectrum signal, the unique word is used for signal tracking and demodulation, and the rate indicator word indicates the transmission rate of the current frame; the broadcast data area is used to transmit the broadcast data of the satellite payload; the service data area consists of multiple data blocks and is used to transmit the service data of the satellite payload.

[0012] Step 2-3: The downlink signal is transmitted in a fixed period. The satellite payload generates downlink signals only in the effective period. If the amount of downlink service data is less than the amount of data in the effective period, the satellite payload will fill the service data area with blank data to ensure the continuity of the downlink signal period.

[0013] Step 2-4: The high-speed aircraft uses a spread spectrum receiver to receive the downlink signal. If the downlink signal of a certain period is correctly captured, the high-speed aircraft calculates the range of the frequency deviation and code phase of the signal of the next period based on the frequency deviation and code phase of the downlink signal and the motion state of the high-speed aircraft within the period, thereby capturing the downlink signal of the next period; the calculation means that since the period is fixed, the motion state of the high-speed aircraft within the period is known, and since the high-orbit satellite can be considered to be stationary within a period, the difference between the frequency deviation and code phase captured in the next period brought by Doppler and the spectrum and code phase of the current period can be calculated according to the motion of the high-speed aircraft, so the downlink signal of the next period can be captured;

[0014] Step 2-5: All high-speed aircraft share one downlink signal. The broadcast data block in the broadcast data area can be parsed by all high-speed aircraft. The data block in the service data area contains the target device information. Each high-speed aircraft can only parse its own data block.

[0015] Step 3: Set the uplink signal of the satellite-to-ground spread spectrum communication system:

[0016] Step 3-1: Each high-speed aircraft has an uplink signal, which adopts a direct sequence spread spectrum system; the uplink channel multiple access method selects frequency division multiple access plus code division multiple access to ensure that the spread spectrum codes of different or same frequencies are different between each other;

[0017] Step 3-2: The uplink signal physical frame consists of a frame header and a service data area, wherein the frame header contains a synchronization word, a unique word and a rate indicator word; the synchronization word of the frame header is used for synchronous capture of spread spectrum signals, the unique word is used for signal tracking and demodulation, and the rate indicator word indicates the transmission rate of the current frame; the service data area is used to transmit service data of ground equipment;

[0018] Step 3-3: The uplink signal is transmitted in burst mode. The uplink signal is generated and transmitted only when a high-speed aircraft has business data requirements.

[0019] Step 3-4: The satellite uses frequency division multiple access plus code division multiple access to distinguish uplink channels, and uses a spread spectrum receiver with a frequency domain parallel acquisition algorithm and a frequency locked loop assisted phase locked loop tracking algorithm to receive a single uplink signal, ensuring that each uplink signal is correctly received;

[0020] Step 3-5: The satellite broadcasts uplink channel access information through the downlink signal broadcast data area, including the occupied uplink channels and the corresponding occupied high-speed aircraft; the high-speed aircraft selects the uplink channel according to the access information to ensure that the uplink channels do not conflict with each other;

[0021] Step 4: When a new high-speed aircraft is ready to access the satellite-to-ground spread spectrum communication system, the access process is as follows:

[0022] Step 4-1: The admitted high-speed aircraft first receives and analyzes the downlink signal from the satellite, and obtains the access information of the uplink channel through the downlink signal broadcast data area;

[0023] Step 4-2: According to the access information of the uplink channel, the admitted high-speed aircraft selects an idle channel to determine the frequency and spread spectrum code, and transmits access request information to the satellite on this idle channel; if there is no idle uplink channel, wait until an idle channel appears;

[0024] Step 4-3: After the satellite correctly receives the request information from the access device, it updates the uplink channel and high-speed aircraft information to the access status in the access information of the downlink signal broadcast data area;

[0025] Step 4-4: After the admitted high-speed aircraft recognizes itself as in access status from the access information in the broadcast data area, it transmits uplink services and the access is completed;

[0026] Step 4-5: If the satellite does not respond in the downlink broadcast data area within a certain period of time after the high-speed aircraft transmits the access request information, the high-speed aircraft will retransmit the access request information; if there is no response again, the high-speed aircraft will randomly select a new idle channel to transmit the access request information, and so on, until the high-speed aircraft is connected to the system;

[0027] Step 5: Prevent uplink channel conflicts;

[0028] Step 5-1: When the connected high-speed aircraft has no business data transmission within the set time, the satellite will release its uplink channel and notify the high-speed aircraft to cancel the access status in the downlink broadcast data area. If the high-speed aircraft has new business needs, it needs to re-access the system;

[0029] Step 5-2: When multiple high-speed aircraft are preparing to access the system at the same time and happen to choose the same idle channel, if the access request information does not arrive at the same time, the satellite will allocate the idle channel to the high-speed aircraft whose access request information is correctly received first and notify it in the downlink broadcast data area. The remaining high-speed aircraft will choose other idle channels for access; if the access request information arrives at the same time and interferes with each other, the high-speed aircraft will not receive a response from the satellite in the downlink broadcast data area within a certain period of time and will request access again; if the satellite does not respond again, the high-speed aircraft will each choose a new idle channel to request access.

[0030] Preferably, in step 2, the downlink signal supports multiple rates, the satellite can switch the transmission rate according to business requirements and link status, and choose to transmit the data volume of each high-speed aircraft in a single frame; the high-speed aircraft can adaptively receive downlink signals of different rates according to the rate indicator.

[0031] Preferably, in step 3, the uplink signal supports multiple rates, and the high-speed aircraft can switch the transmission rate according to business requirements and link status; the satellite can adaptively receive downlink signals of different rates according to the rate indicator.

[0032] A computer program, wherein the computer program enables a computer to execute the above-mentioned satellite-to-ground spread spectrum communication method.

[0033] An electronic device comprises: a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the electronic device executes the above-mentioned satellite-to-ground spread spectrum communication method.

[0034] A computer-readable storage medium stores a computer program, which implements the satellite-to-ground spread spectrum communication method when executed by a processor.

[0035] A chip includes: a processor, which is used to call and run a computer program from a memory, so that a device equipped with the chip executes the above-mentioned satellite-to-ground spread spectrum communication method.

[0036] A computer program product, comprising a computer storage medium storing a computer program, wherein the computer program comprises instructions executable by at least one processor, and when the instructions are executed by the at least one processor, the above-mentioned satellite-to-ground spread spectrum communication method is implemented.

[0037] The beneficial effects of the present invention are as follows:

[0038] Engineering tests have shown that the present invention can be implemented on a common hardware platform to meet communication requirements under high dynamic conditions.

[0039] (1) Downlink signals are transmitted periodically, and uplink signals are transmitted in bursts. Therefore, the resource consumption is very small for high-speed aircraft, which ensures the miniaturization of high-speed aircraft equipment and reduces the design difficulty and manufacturing cost of ground equipment.

[0040] (2) The uplink channels are replaceable, which means that when some uplink channels fail due to interference, the high-speed aircraft designed with this system can replace the uplink channels and reconnect to the system, making the entire system more resistant to interference;

[0041] (3) The impact of multiple high-speed aircraft accessing at the same time is fully considered, and access information is broadcasted through downlink signals to notify high-speed aircraft in real time, ensuring that high-speed aircraft can quickly access the system;

[0042] (4) The system functional structure of the present invention is clear, the satellite and the high-speed aircraft are relatively independent, the implementation is simple, and no additional processing complexity is introduced. The flexibility of the system is increased, different usage requirements are met, and the modular design and debugging of the system are facilitated. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a block diagram of the satellite-to-ground spread spectrum communication system of the present invention;

[0044] Figure 2 It is a frame structure diagram of the satellite-ground integrated downlink signal of the present invention;

[0045] Figure 3 This is a frame structure diagram of the satellite-ground integrated uplink signal of the present invention;

[0046] Figure 4 A schematic diagram of a frequency domain parallel acquisition algorithm used in the present invention;

[0047] Figure 5 A schematic diagram of a tracking algorithm of a frequency-locked loop assisted phase-locked loop used in the present invention;

[0048] Figure 6 This is a flow chart of the access of the high-speed aircraft of the present invention. DETAILED DESCRIPTION

[0049] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0050] The purpose of the present invention is to overcome the shortcomings of the existing communication system under high dynamic conditions, adapt to the high dynamic communication requirements between satellites and high-speed aircraft, and provide a stable and reliable satellite-to-ground communication method under high dynamic conditions. The method adopts a satellite-to-ground integrated spread spectrum communication system, uses periodic signals in the satellite transmitting unit, and maintains the stability of the link according to the formulated scheduling strategy; and adopts a frequency domain parallel capture algorithm and a frequency tracking algorithm of a frequency-locked loop assisted phase-locked loop in the satellite receiving end to ensure reliable reception under high dynamic conditions.

[0051] This method solves the problem of high-dynamic communication between satellites and high-speed aircraft, and greatly improves the application efficiency of satellites in the field of high-speed aircraft.

[0052] In order to achieve the above object, the technical solution of the present invention is:

[0053] A satellite-to-ground spread spectrum communication method under high dynamic conditions first constructs a satellite-to-ground spread spectrum communication system under high dynamic conditions, which consists of a satellite and a high-speed aircraft. The satellite can communicate data with multiple high-speed aircraft, including transmitting downlink signals to the high-speed aircraft, and receiving and processing uplink signals from the high-speed aircraft.

[0054] The technical solution for downlink signal is:

[0055] (1) The downlink signal adopts the direct sequence spread spectrum system, which spreads the signal carrying information before transmission. Since the spread spectrum function is very close to the statistical characteristics of white noise, spread spectrum communication has strong resistance to human interference, narrowband interference and multipath interference.

[0056] (2) The physical frame of the downlink signal consists of a frame header, a broadcast data area, and a service data area. The frame header contains a synchronization word, a unique word, and a rate indicator. The synchronization word in the frame header is used for synchronous capture of spread spectrum signals, the unique word is used for signal tracking and demodulation, and the rate indicator indicates the transmission rate of the current frame; the broadcast data area transmits the broadcast data of the satellite payload; and the service data area consists of multiple data blocks and transmits the service data of the satellite payload.

[0057] (3) The downlink signal is transmitted in a fixed period. The satellite payload generates downlink signals only during the effective period. If the amount of downlink service data is less than the amount of data during the effective period, the satellite payload will fill the service data area with blank data to ensure the continuity of the downlink signal period.

[0058] (4) The high-speed aircraft uses an ordinary spread spectrum receiver to receive the downlink signal. If the downlink signal of a certain period is correctly captured, the high-speed aircraft can calculate the precise range of the frequency deviation and code phase of the signal of the next period based on the frequency deviation and code phase of the signal and the motion state of the high-speed aircraft within the period, thereby quickly and accurately capturing the downlink signal of the next period. This process can be repeated and the stable reception of the downlink signal can be ensured.

[0059] (5) All high-speed aircraft share one downlink signal. The broadcast data blocks in the broadcast data area can be parsed by all high-speed aircraft. The data blocks in the business data area contain target device information, and each high-speed aircraft can only parse its own data blocks.

[0060] (6) The downlink signal supports multiple rates and flexible allocation of service data blocks. The satellite can switch the transmission rate according to service requirements and link status, and choose to transmit the data volume of each high-speed aircraft in a single frame; the high-speed aircraft can adaptively receive downlink signals of different rates based on the rate indicator.

[0061] The technical solution for uplink signal is:

[0062] (1) Each high-speed aircraft has an uplink signal, which uses a direct sequence spread spectrum system. The uplink channel multiple access method selects frequency division multiple access plus code division multiple access to ensure that the spread spectrum codes between two frequencies are different or the same.

[0063] (2) The uplink signal physical frame consists of a frame header and a service data area. The frame header contains a synchronization word, a unique word, and a rate indicator. The synchronization word in the frame header is used for synchronous capture of spread spectrum signals, the unique word is used for signal tracking and demodulation, and the rate indicator indicates the transmission rate of the current frame. The service data area transmits the service data of the ground equipment.

[0064] (3) The uplink signal is transmitted in burst mode. An uplink signal is generated for transmission only when a high-speed aircraft has business data communication needs.

[0065] (4) The satellite uses frequency division multiple access plus code division multiple access to distinguish uplink channels, and adopts a spread spectrum receiver with a frequency domain parallel acquisition algorithm and a frequency locked loop assisted phase locked loop tracking algorithm to receive single-channel uplink signals, ensuring the correct reception of each uplink signal.

[0066] (5) The satellite broadcasts uplink channel access information through the downlink signal broadcast data area, including the occupied uplink channels and the corresponding occupied high-speed aircraft; the high-speed aircraft selects the appropriate uplink channel based on the access information to ensure that there is no conflict between the uplink channels.

[0067] (6) The uplink signal supports multiple rates. High-speed aircraft can switch the transmission rate according to business needs and link status. The satellite can adaptively receive downlink signals of different rates based on the rate indicator.

[0068] When a new high-speed aircraft is ready to be connected to the system, the connection process is:

[0069] (1) The high-speed aircraft that is allowed to enter first receives and analyzes the downlink signal from the satellite, and obtains the access information of the uplink channel through the broadcast data area of ​​the downlink signal.

[0070] (2) Based on the access information of the uplink channel, the admitted high-speed aircraft selects a suitable idle channel to determine the frequency and spread spectrum code, and transmits access request information to the satellite on this idle channel. If there is no idle uplink channel in the current system, it waits until an idle channel appears.

[0071] (3) After the satellite correctly receives the request information from the access device, it updates the uplink channel and high-speed aircraft information to the access status in the access information of the downlink signal broadcast data area.

[0072] (4) After the admitted high-speed aircraft identifies itself as in access status from the access information in the broadcast data area, it can transmit uplink services in this uplink channel, and the access is completed.

[0073] (5) If the satellite does not respond in the downlink broadcast data area within a certain period of time after the high-speed aircraft transmits the access request information, the high-speed aircraft will retransmit the access request information; if there is no response again, the high-speed aircraft will randomly select a new idle channel to transmit the access request information, and so on, until the high-speed aircraft is connected to the system.

[0074] To prevent uplink channel conflicts and ensure reasonable use of resources, the method is:

[0075] (1) When a high-speed aircraft has no business data transmission within a certain period of time, the satellite will release its uplink channel and notify the high-speed aircraft in the downlink broadcast data area to cancel the access status. If the high-speed aircraft has new business needs, it needs to re-access the system.

[0076] (2) When multiple high-speed aircraft are preparing to access the system at the same time and happen to choose the same idle channel, if the access request information does not arrive at the same time, the satellite will allocate the idle channel to the high-speed aircraft whose access request information is correctly received first and notify it in the downlink broadcast data area. The remaining high-speed aircraft will choose other idle channels for access. If the access request information arrives at the same time and interferes with each other, the high-speed aircraft will not receive a response from the satellite in the downlink broadcast data area within a certain period of time and will request access again. If the satellite does not respond again, the high-speed aircraft will each choose a new idle channel to request access.

[0077] Example:

[0078] by Figure 1As shown, the satellite-to-ground spread spectrum communication system constructed by the present invention consists of two parts: a satellite (equipped with a high-dynamic communication payload) and a high-speed aircraft (equipped with a high-dynamic spread spectrum communication terminal). The satellite broadcasts downlink signals to the high-speed aircraft and receives and processes uplink signals from ground equipment.

[0079] The downlink signal uses direct sequence spread spectrum technology to spread the information-bearing signal before transmission. Since the spread spectrum function is very close to the statistical characteristics of white noise, spread spectrum communication has a strong ability to resist human interference, narrowband interference, and multipath interference.

[0080] by Figure 2 As shown in the figure, the physical frame of the downlink signal consists of a frame header, a broadcast data area and a service data area, wherein the frame header contains a synchronization word, a unique word and a rate indicator. The synchronization word of the frame header is used for synchronous capture of spread spectrum signals, the unique word is used for signal tracking and demodulation, and the rate indicator indicates the transmission rate of the current frame; the broadcast data area transmits the satellite's broadcast data; and the service data area consists of multiple data blocks, which transmit the satellite's service data.

[0081] The downlink signal is transmitted in a fixed period, and the satellite only generates downlink signals during the effective period. If the amount of downlink service data is less than the amount of data in the effective period, the satellite will fill the service data area with blank data to ensure the continuity of the downlink signal period.

[0082] High-speed aircraft uses ordinary spread spectrum receivers to receive downlink signals. If the downlink signal of a certain period is correctly captured, the high-speed aircraft can calculate the precise range of the frequency deviation and code phase of the signal of the next period based on the frequency deviation and code phase of the signal and the motion state of the high-speed aircraft within the period, thereby quickly and accurately capturing the downlink signal of the next period. And so on, to ensure the stable reception of the downlink signal.

[0083] All high-speed aircraft share one downlink signal, and all high-speed aircraft can parse the broadcast data block in the broadcast data area; the data block in the business data area contains the target device information, and each high-speed aircraft can only parse its own data block.

[0084] The downlink signal supports multiple rates and flexible allocation of business data blocks. The satellite can switch the transmission rate according to business needs and link status, and choose to transmit the data volume of each high-speed aircraft in a single frame; the high-speed aircraft can adaptively receive downlink signals of different rates based on the rate indicator.

[0085] Each high-speed aircraft has an uplink signal, which uses a direct sequence spread spectrum system. The uplink channel multiple access method selects frequency division multiple access plus code division multiple access to ensure that the frequencies are different or the spread spectrum codes are different between the two frequencies.

[0086] by Figure 3As shown in the figure, the uplink signal physical frame consists of a frame header and a service data area, where the frame header contains a synchronization word, a unique word and a rate indicator. The synchronization word in the frame header is used for synchronous capture of spread spectrum signals, the unique word is used for signal tracking and demodulation, and the rate indicator indicates the transmission rate of the current frame; the service data area transmits the service data of high-speed aircraft.

[0087] The uplink signal is transmitted in burst mode. An uplink signal is generated for transmission only when a high-speed aircraft has business data requirements.

[0088] The satellite uses frequency division multiple access plus code division multiple access to distinguish uplink channels. Figure 4 The frequency domain parallel acquisition algorithm shown in Figure 5 The spread spectrum receiver with the frequency-locked loop assisted phase-locked loop tracking algorithm shown receives a single uplink signal, ensuring the correct reception of each uplink signal.

[0089] The satellite broadcasts uplink channel access information through the downlink signal broadcast data area, including the occupied uplink channels and the corresponding occupied high-speed aircraft; the high-speed aircraft selects the appropriate uplink channel based on the access information to ensure that the uplink channels do not conflict with each other.

[0090] The uplink signal supports multiple rates, and high-speed aircraft can switch the transmission rate according to business needs and link status; the satellite can adaptively receive downlink signals of different rates based on the rate indicator.

[0091] like Figure 6 As shown in the figure, when a new high-speed aircraft is ready to access the system, the access process is:

[0092] (1) The high-speed aircraft receives the downlink signal and obtains the uplink channel access information through the downlink signal broadcast data area.

[0093] (2) Based on the channel access information, if there is an idle uplink channel, randomly select an idle channel and request access to the satellite on this channel; if there is no idle channel, continue to parse the uplink channel access information until an idle channel appears.

[0094] (3) If the satellite correctly receives the access request, it will update the uplink channel and the high-speed aircraft to the access status in the access information of the downlink signal.

[0095] (4) After the high-speed aircraft identifies its access status from the access information, it can transmit business data in this uplink channel, and the device access is completed.

[0096] (5) If the satellite does not correctly receive the access request and cannot respond in the downlink signal, the high-speed aircraft will request access on this channel again after a certain period of time. If there is no response again after a certain period of time, the high-speed aircraft will change to a new idle channel to request access until step (3) is completed.

[0097] When a connected high-speed aircraft has no business data transmission within a certain period of time, the satellite will release its uplink channel and notify the high-speed aircraft to cancel the access status in the downlink broadcast data area. If the high-speed aircraft has new business needs, it needs to re-access the system.

[0098] When multiple high-speed aircraft are preparing to access the system at the same time and happen to choose the same idle channel, if the access requests do not conflict in time, the satellite will assign the idle channel to the high-speed aircraft that first correctly receives the access request and notify it in the downlink broadcast. The remaining high-speed aircraft will switch to other idle channels for access. If the access requests conflict in time and the satellite cannot respond in the downlink signal, the high-speed aircraft will request again according to step (5). If there is no response again, it will switch to other idle channels. The channels changed by each high-speed aircraft are random.

Claims

1. A satellite-to-ground spread spectrum communication method under high dynamic conditions, characterized in that: The steps include: Step 1: Construct a satellite-to-ground spread spectrum communication system under high dynamic conditions, which consists of two parts: a satellite and a high-speed aircraft; the satellite can communicate data with multiple high-speed aircraft, including transmitting downlink signals to the high-speed aircraft, and receiving and processing uplink signals from the high-speed aircraft; Step 2: Set the downlink signal of the satellite-to-ground spread spectrum communication system; Step 2-1: The downlink signal adopts the direct sequence spread spectrum system, and the signal carrying information is spread before transmission; Step 2-2: The physical frame of the downlink signal consists of a frame header, a broadcast data area and a service data area, wherein the frame header includes a synchronization word, a unique word and a rate indicator word; The synchronization word in the frame header is used for synchronous capture of spread spectrum signals, the unique word is used for signal tracking and demodulation, and the rate indicator word indicates the transmission rate of the current frame; The broadcast data area is used to transmit broadcast data of satellite payload; The service data area consists of multiple data blocks and is used to transmit the service data of the satellite payload; Step 2-3: The downlink signal is transmitted in a fixed period. The satellite payload generates downlink signals only in the effective period. If the amount of downlink service data is less than the amount of data in the effective period, the satellite payload will fill the service data area with blank data to ensure the continuity of the downlink signal period. Step 2-4: The high-speed aircraft uses a spread spectrum receiver to receive the downlink signal. If the downlink signal of a certain period is correctly captured, the high-speed aircraft calculates the range of the frequency deviation and code phase of the signal of the next period based on the frequency deviation and code phase of the downlink signal and the motion state of the high-speed aircraft within the period, thereby capturing the downlink signal of the next period; Step 2-5: All high-speed aircraft share one downlink signal. The broadcast data block in the broadcast data area can be parsed by all high-speed aircraft. The data block in the service data area contains the target device information. Each high-speed aircraft can only parse its own data block. Step 3: Set the uplink signal of the satellite-to-ground spread spectrum communication system: Step 3-1: Each high-speed aircraft has an uplink signal, which adopts a direct sequence spread spectrum system; the uplink channel multiple access method selects frequency division multiple access plus code division multiple access to ensure that the spread spectrum codes of different or same frequencies are different between each other; Step 3-2: The uplink signal physical frame consists of a frame header and a service data area, wherein the frame header includes a synchronization word, a unique word and a rate indicator word; The synchronization word in the frame header is used for synchronous capture of spread spectrum signals, the unique word is used for signal tracking and demodulation, and the rate indicator word indicates the transmission rate of the current frame; the service data area is used to transmit service data of ground equipment; Step 3-3: The uplink signal is transmitted in burst mode. The uplink signal is generated and transmitted only when a high-speed aircraft has business data requirements. Step 3-4: The satellite uses frequency division multiple access plus code division multiple access to distinguish uplink channels, and uses a spread spectrum receiver with a frequency domain parallel acquisition algorithm and a frequency locked loop assisted phase locked loop tracking algorithm to receive a single uplink signal, ensuring that each uplink signal is correctly received; Step 3-5: The satellite broadcasts uplink channel access information through the downlink signal broadcast data area, including the occupied uplink channels and the corresponding occupied high-speed aircraft; the high-speed aircraft selects the uplink channel according to the access information to ensure that the uplink channels do not conflict with each other; Step 4: When a new high-speed aircraft is ready to access the satellite-to-ground spread spectrum communication system, the access process is as follows: Step 4-1: The admitted high-speed aircraft first receives and analyzes the downlink signal from the satellite, and obtains the access information of the uplink channel through the downlink signal broadcast data area; Step 4-2: According to the access information of the uplink channel, the admitted high-speed aircraft selects an idle channel to determine the frequency point and spread spectrum codeword, and transmits access request information to the satellite on this idle channel; If there is no idle uplink channel, wait until an idle channel appears; Step 4-3: After the satellite correctly receives the request information from the access device, it updates the uplink channel and high-speed aircraft information to the access status in the access information of the downlink signal broadcast data area; Step 4-4: After the admitted high-speed aircraft recognizes itself as in access status from the access information in the broadcast data area, it transmits uplink services and the access is completed; Step 4-5: If the satellite does not respond in the downlink broadcast data area within a certain period of time after the high-speed aircraft transmits the access request information, the high-speed aircraft will retransmit the access request information; if there is no response again, the high-speed aircraft will randomly select a new idle channel to transmit the access request information, and so on, until the high-speed aircraft is connected to the system; Step 5: Prevent uplink channel conflicts; Step 5-1: When the connected high-speed aircraft has no business data transmission within the set time, the satellite will release its uplink channel and notify the high-speed aircraft to cancel the access status in the downlink broadcast data area. If the high-speed aircraft has new business needs, it needs to re-access the system; Step 5-2: When multiple high-speed aircraft are preparing to access the system at the same time and happen to choose the same idle channel, if the access request information does not arrive at the same time, the satellite will allocate the idle channel to the high-speed aircraft whose access request information is correctly received first and notify it in the downlink broadcast data area. The remaining high-speed aircraft will choose other idle channels for access; if the access request information arrives at the same time and interferes with each other, the high-speed aircraft will not receive a response from the satellite in the downlink broadcast data area within a certain period of time and will request access again; if the satellite does not respond again, the high-speed aircraft will each choose a new idle channel to request access.

2. The satellite-to-ground spread spectrum communication method under high dynamic conditions according to claim 1, characterized in that: In step 2, the downlink signal supports multiple rates, and the satellite can switch the transmission rate according to business requirements and link status, and choose to transmit the data volume of each high-speed aircraft in a single frame; the high-speed aircraft can adaptively receive downlink signals of different rates according to the rate indicator.

3. The satellite-to-ground spread spectrum communication method under high dynamic conditions according to claim 2, characterized in that: In step 3, the uplink signal supports multiple rates, and the high-speed aircraft can switch the transmission rate according to business requirements and link status; the satellite can adaptively receive downlink signals of different rates according to the rate indicator.

4. An electronic device, characterized in that: include: Processor and memory; The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the electronic device executes the method as claimed in any one of claims 1 to 3.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 3 is implemented.

6. A chip, characterized in that: include: A processor, configured to call and run a computer program from a memory, so that a device equipped with the chip executes a method as claimed in any one of claims 1 to 3.

7. A computer program product, characterized in that The computer program product comprises a computer storage medium storing a computer program, wherein the computer program comprises instructions executable by at least one processor, and when the instructions are executed by the at least one processor, the method according to any one of claims 1 to 3 is implemented.

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