阅读说明：本技术 一种卫星激光通信方法 (Satellite laser communication method ) 是由 向晓霞 杨峰 任维佳 杜志贵 于 2018-11-07 设计创作，主要内容包括：本发明涉及一种卫星激光通信方法,所述方法包括：在飞行器尝试与第一低轨卫星建立激光通信链路时,飞行器发射激光束指向具有确定位置的第一同步卫星以请求建立飞行器第一同步卫星的激光通信链路；确定飞行器的姿态和位置之后,至少根据确定的飞行器的姿态和位置尝试建立飞行器和第一低轨卫星之间的激光通信链路,并通过飞行器和第一低轨卫星之间建立的激光通信链路在飞行器和第一低轨卫星之间直接传输数据。(The invention relates to a satellite laser communication method, which comprises the following steps: when the aircraft attempts to establish a laser communication link with a first low earth orbit satellite, the aircraft emits a laser beam directed at a first synchronization satellite having a determined position to request establishment of the laser communication link of the first synchronization satellite of the aircraft; after determining the attitude and position of the aerial vehicle, attempting to establish a laser communication link between the aerial vehicle and the first low-earth-orbit satellite based at least on the determined attitude and position of the aerial vehicle, and transmitting data directly between the aerial vehicle and the first low-earth-orbit satellite via the established laser communication link between the aerial vehicle and the first low-earth-orbit satellite.)

1. A method for satellite laser communication, the method comprising: when the aircraft (100) attempts to establish a laser communication link with the first low earth orbit satellite (210), the aircraft (100) transmits a laser beam directed at a first synchronization satellite (310) having a determined position to request establishment of a laser communication link between the aircraft (100) and the first synchronization satellite (310);

after determining the attitude and position of the aircraft (100), attempting to establish a laser communication link between the aircraft (100) and the first low-earth satellite (210) based at least on the determined attitude and position of the aircraft (100), and transmitting data directly between the aircraft (100) and the first low-earth satellite (210) over the established laser communication link between the aircraft (100) and the first low-earth satellite (210).

2. The satellite laser communication method of claim 1, wherein determining the attitude and position of at least one of the aerial vehicle (100) and the first low-earth satellite (210) is accomplished prior to establishing the laser communication link between the aerial vehicle (100) and the first low-earth satellite (210),

after determining the attitude and position of the aerial vehicle (100) or the first low earth orbit satellite (210) is completed, the first low earth orbit satellite (210) or the aerial vehicle (100) of which the attitude and position is not determined transmits a laser beam scan toward the aerial vehicle (100) of which the attitude and position is determined or the first low earth orbit satellite (210) to attempt to establish a laser communication link between the aerial vehicle (100) and the first low earth orbit satellite (210);

in the process that the first low-earth satellite (210) or the aircraft (100) of which the attitude and the position are not determined emits the laser beam toward the aircraft (100) of which the attitude and the position are determined or the first low-earth satellite (210) in an attempt to establish the laser communication link between the aircraft (100) and the first low-earth satellite (210), the determination process of the first low-earth satellite (210) or the aircraft (100) of which the attitude and the position are not determined is not terminated until the attempt to establish the laser communication link between the aircraft (100) and the first low-earth satellite (210) is successful or the system determines the attitude and the position of the first low-earth satellite (210) or the aircraft (100) of which the attitude and the position are not determined.

3. The satellite laser communication method according to claim 2, wherein after the laser communication link is established between the aircraft (100) and the first low-orbit satellite (210), the first synchronization satellite (310) maintains the laser communication link established between the aircraft (100) and/or the first low-orbit satellite (210) until the data transmission between the aircraft (100) and the first low-orbit satellite (210) is completed, and the first synchronization satellite (310) identifies a link state of the laser communication link established between the aircraft (100) and the first low-orbit satellite (210) and a transmission state of the data transmitted through the laser communication link, and in the case where the transmission state is an uncompleted state and the link state is an unavailable state,

the first synchronous satellite (310) sends a request for assisting data transmission to the aircraft (100) and the first low-orbit satellite (210), and after the aircraft (100) and the first low-orbit satellite (210) both receive the request for assisting data transmission sent by the first synchronous satellite (310), the aircraft (100) and the first low-orbit satellite (210) indirectly transmit data through a laser communication link established by the aircraft (100) and the first synchronous satellite (310) and a laser communication link established by the first synchronous satellite (310) and the first low-orbit satellite (210).

4. A satellite laser communication method according to claim 3, wherein before the aircraft (100) emits the laser beam directed to the first geostationary satellite (310) having the determined position, the aircraft (100) selects a geostationary satellite capable of establishing a laser communication link with both the aircraft (100) and the first low-earth satellite (210) as the first geostationary satellite (310) based on the ephemeris data, and transmits the selected first geostationary satellite (310) to the first low-earth satellite (210) together with a message that the aircraft (100) requests to establish a laser communication link with the first low-earth satellite (210) in a non-optical communication manner;

the first low earth satellite (210) establishing a laser communication link between the first low earth satellite (210) and the first synchronization satellite (310) in response to the selected first synchronization satellite (310) and the message that the aircraft (100) requests that a laser communication link be established with the first low earth satellite (210);

determining an attitude and a position of a first low-orbit satellite (210) based at least in part on a second ATP device (211) pointing and tracking the first low-orbit satellite (210) of the first synchronous satellite (310) after establishing a laser communication link between the first low-orbit satellite (210) and the first synchronous satellite (310);

after determining the attitude and position of the first low-earth satellite (210), attempting to establish a laser communication link between the aerial vehicle (100) and the first low-earth satellite (210) based at least on the determined attitude and position of the first low-earth satellite (210), and transmitting data directly between the aerial vehicle (100) and the first low-earth satellite (210) over the established laser communication link between the aerial vehicle (100) and the first low-earth satellite (210).

5. The satellite laser communication method according to claim 4, wherein when the aircraft (100) and the first low earth orbit satellite (210) directly transmit data through the laser communication link established between the aircraft (100) and the first low earth orbit satellite (210), the transmitted data is transmitted in clear or encrypted using a first encryption algorithm; and/or

Encrypting the transmission data using a second encryption algorithm different from the first encryption algorithm while the aircraft (100) and the first low-earth satellite (210) transmit the data over the laser communication link established by the aircraft (100) and the first synchronization satellite (310) and the laser communication link established by the first synchronization satellite (310) and the first low-earth satellite (210);

wherein the key for encrypting the data of the first encryption algorithm and/or the second encryption algorithm is transmitted directly over the laser communication link established between the aircraft (100) and the first low earth orbit satellite (210) when the link status of the laser communication link established between the aircraft (100) and the first low earth orbit satellite (210) is in the available state.

6. The satellite laser communication method according to claim 5, wherein after the laser communication link is established between the aerial vehicle (100) and the first low-earth satellite (210) and before the data to be encrypted is transmitted, the aerial vehicle (100) and the first low-earth satellite (210) need to perform a key generation process and a key transmission process;

the key generation process comprises the following steps: the aircraft (100) or the first low-orbit satellite (210) generates a symmetric key for a first encryption algorithm, the aircraft (100) generates a first asymmetric key for a second encryption algorithm, the first low-orbit satellite (210) generates a second asymmetric key for the second encryption algorithm, the first asymmetric key comprises a first public key and a first private key, and the second asymmetric key comprises a second public key and a second private key;

the key transmission process comprises the following steps: the aircraft (100) or the first low-orbit satellite (210) transmits the generated symmetric key to the first low-orbit satellite (210) or the aircraft (100) through a laser communication link established between the aircraft (100) and the first low-orbit satellite (210), the aircraft (100) transmits the generated first public key to the first low-orbit satellite (210) through a laser communication link established between the aircraft (100) and the first low-orbit satellite (210), and the first low-orbit satellite (210) transmits the generated second public key to the aircraft (100) through a laser communication link established between the aircraft (100) and the first low-orbit satellite (210).

7. The satellite laser communication method of claim 6, further comprising:

the aircraft (100) generates at least two symmetric keys corresponding to the at least two security levels and generates at least two sets of first asymmetric keys corresponding to the at least two security levels, the higher the security level the symmetric keys or the first asymmetric keys are assigned the longer the key length,

prior to the aircraft (100) transmitting data to the first low-orbit satellite (210) over the laser communication link established between the aircraft (100) and the first low-orbit satellite (210), the aircraft (100) determining a level of security required to transmit data to the first low-orbit satellite (210), and selecting a key required to encrypt the data based on the level of security determined by the aircraft (100) to be required to transmit data to the first low-orbit satellite (210); and/or

The first low earth orbit satellite (210) generates at least two sets of second asymmetric keys corresponding to at least two security levels, the higher the security level, the longer the second asymmetric keys are assigned, the first low earth orbit satellite (210) determines a security level required to transmit data to the aircraft (100) before the first low earth orbit satellite (210) transmits data to the aircraft (100) over the laser communication link established between the aircraft (100) and the first low earth orbit satellite (210), and selects the key required to encrypt the data based on the security level determined by the first low earth orbit satellite (210) to transmit data to the aircraft (100).

8. The satellite laser communication method according to claim 7, wherein after selecting the key required to encrypt the data according to the determined security level required to transmit the data to the first low-orbit satellite (210) and before transmitting the encrypted data to the first low-orbit satellite (210), the aircraft (100) transmits the security level determined by the aircraft (100) required to transmit the data to the first low-orbit satellite (210) to enable the decryption key adapted thereto; and/or

After selecting the key required for encrypting the data according to the determined security level required for transmitting the data to the aircraft (100) and before transmitting the encrypted data to the aircraft (100), the first low-earth satellite (210) transmits the security level determined by the first low-earth satellite (210) required for transmitting the data to the aircraft (100) for the aircraft (100) to enable the decryption key adapted thereto.

9. The satellite laser communication method according to claim 8, wherein before the aircraft (100) transmits the determined security level required for transmitting data to the first low-orbit satellite (210), the security level required for transmitting data to the first low-orbit satellite (210) determined by the aircraft (100) is transmitted to the first low-orbit satellite (210) after being encrypted by a first private key corresponding to the highest security level generated by the aircraft (100) and a second public key corresponding to the highest security level generated by the first low-orbit satellite (210); and/or

Before the first low-orbit satellite (210) sends the determined security level required for transmitting the data to the aircraft (100), the security level required for transmitting the data to the aircraft (100) and determined by the first low-orbit satellite (210) is encrypted by using a second private key corresponding to the highest security level and a first public key corresponding to the highest security level and generated by the aircraft (100) and sent to the aircraft (100).

10. The satellite laser communication method according to claim 9, wherein the received security level determined by the first low earth orbit satellite (210) to be required for transmitting data to the aircraft (100) is decrypted using a first private key corresponding to the highest security level generated by the aircraft (100) and a second public key corresponding to the highest security level generated by the first low earth orbit satellite (210) and the decryption key adapted thereto is enabled to decrypt the corresponding data transmitted by the first low earth orbit satellite (210) accordingly; and/or

The first low-earth satellite (210) is further configured to: and decrypting the security level determined by the received aircraft (100) and required for transmitting the data to the first low-orbit satellite (210) by using the second private key corresponding to the highest security level generated by the first low-orbit satellite (210) and the first public key corresponding to the highest security level generated by the aircraft (100) and enabling the decryption key adapted to the second private key to decrypt the corresponding data transmitted by the aircraft (100).

Technical Field

The invention relates to the field of satellite communication, in particular to a satellite laser communication system.

Background

Satellite communication is a combination of aerospace, communication, information and new material technologies, is one of the world high-precision technologies, and embodies the comprehensive strength of the state in the high and new technology fields in the information age. The satellite communication industry, as an important component of the information communication industry, plays an increasingly important role in the construction of national information infrastructure, the realization of universal services, the creation of a harmonious information society, and the national security strategy.

Currently, airborne communication is mainly achieved by microwave satellites. In the case of communication by microwave radio, since radio frequency is a base for normal communication between an aircraft and a satellite and is a channel for information transmission, in order to prevent electromagnetic interference between satellites, it is necessary to maintain a certain interval of communication frequency for frequency isolation, and thus the radio spectrum is strictly regulated by the International Telecommunications Union (ITU) and governments of various countries. In addition, radio communication has the problems of frequency spectrum saturation and limited communication bandwidth, and is difficult to meet the high-speed transmission requirement of mass data, and the real-time transmission of mass flight data of an aircraft cannot be realized. Accordingly, techniques for aircraft to communicate with satellites have emerged. For example, chinese patent publication No. CN108337041A discloses an aircraft communication system, which relates to the technical field of laser communication, and mainly aims to implement laser communication between an aircraft and a satellite, and includes at least one aircraft-satellite laser communication terminal device, an electric cabinet, a fairing, and a bracket with a vibration reduction function; the aircraft-satellite laser communication terminal equipment is communicated with a satellite communication system through a laser link; the electric cabinet is used for supplying power to the aircraft-satellite laser communication terminal equipment and providing control instructions and information flow; the fairing is of an at least partially transparent structure and covers the outer side of the aircraft-satellite laser communication terminal equipment. The invention is mainly used for data transmission of the aircraft. However, it does not consider the problem of how quickly to establish a lower delay laser communication link with geostationary and non-geostationary satellites. In the laser communication between the aircraft and the satellite, if the aircraft directly establishes a laser communication link with the geostationary satellite, although the geostationary satellite is fixed in position and the laser communication link is established faster, the laser communication link is established between the aircraft and the geostationary satellite, but the laser communication link is relatively delayed due to the longer distance between the aircraft and the geostationary satellite. However, if the aircraft directly tries to establish the laser communication link with the low-orbit satellite, the time of the position and attitude changes due to the fact that the low-orbit satellite moves, although the position and attitude of the satellite at the corresponding time can be known by ephemeris data, the accuracy range of the attitude and position determined by the ephemeris data is not accurate enough compared with the establishment of the laser communication link, and the aircraft can also be in a moving state, which further increases the difficulty of directly establishing the laser communication link between the aircraft and the low-orbit satellite, and although the establishment is possible, the establishment time is long. Accordingly, there is a need for improvements in the art to establish a communication link between an aircraft and a low earth orbit satellite in a shorter amount of time.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a satellite laser communication system, which can firstly establish a laser communication link between an aircraft and a synchronous satellite when the aircraft needs to establish the laser communication link with a first low-orbit satellite, determine the position of the aircraft which is more accurate than the position determined by the traditional positioning modules such as GPS, Beidou and the like at least partially based on an ATP device of the aircraft, determine the attitude of the aircraft, and try to establish the laser communication link between the aircraft and the first low-orbit satellite according to the determined attitude and position of the aircraft, thereby greatly shortening the time for establishing the laser communication link between the aircraft and the first low-orbit satellite.

According to a preferred embodiment, a satellite laser communication system comprises: a first synchronous satellite and a first low earth orbit satellite; when the aircraft attempts to establish a laser communication link with a first low earth orbit satellite, the aircraft emits a laser beam directed at a first synchronization satellite having a determined position to request establishment of a laser communication link between the aircraft and the first synchronization satellite; determining an attitude and a position of the aerial vehicle based at least in part on a first ATP device of the aerial vehicle pointing and tracking the first synchronization satellite after establishing the laser communication link between the aerial vehicle and the first synchronization satellite; after determining the attitude and position of the aerial vehicle, attempting to establish a laser communication link between the aerial vehicle and the first low-earth-orbit satellite based at least on the determined attitude and position of the aerial vehicle, and transmitting data directly between the aerial vehicle and the first low-earth-orbit satellite via the established laser communication link between the aerial vehicle and the first low-earth-orbit satellite.

According to a preferred embodiment, before the aircraft emits the laser beam to point at the first synchronous satellite with the determined position, the aircraft selects a synchronous satellite capable of establishing a laser communication link with the aircraft and the first low-orbit satellite as the first synchronous satellite according to the ephemeris data, and sends the selected first synchronous satellite to the first low-orbit satellite through a non-optical communication mode together with a message that the aircraft requests to establish the laser communication link with the first low-orbit satellite; the first low earth orbit satellite responds to the selected first synchronous satellite and the message that the aircraft requests to establish the laser communication link with the first low earth orbit satellite, and a laser communication link is established between the first low earth orbit satellite and the first synchronous satellite; determining an attitude and a position of a first low-orbit satellite based at least in part on a second ATP device pointing and tracking the first low-orbit satellite of the first synchronous satellite after establishing a laser communication link between the first low-orbit satellite and the first synchronous satellite; after determining the attitude and position of the first low-earth satellite, attempting to establish a laser communication link between the aerial vehicle and the first low-earth satellite based at least on the determined attitude and position of the first low-earth satellite, and transmitting data directly between the aerial vehicle and the first low-earth satellite via the established laser communication link between the aerial vehicle and the first low-earth satellite.

According to a preferred embodiment, the determination of the attitude and position of at least one of the aerial vehicle and the first low-earth satellite is done before the establishment of the laser communication link between the aerial vehicle and the first low-earth satellite, and after the determination of the attitude and position of the aerial vehicle or the first low-earth satellite is done, the first low-earth satellite or the aerial vehicle of which the attitude and position is not determined emits a laser beam scan toward the aerial vehicle of which the attitude and position is determined or the first low-earth satellite in an attempt to establish the laser communication link between the aerial vehicle and the first low-earth satellite; in the process that the first low-earth satellite or the aircraft of which the attitude and the position are not determined emits the laser beam toward the aircraft of which the attitude and the position are determined or the first low-earth satellite to attempt to establish the laser communication link between the aircraft and the first low-earth satellite, the determination process of the first low-earth satellite or the aircraft of which the attitude and the position are not determined is not terminated until the attempt to establish the laser communication link between the aircraft and the first low-earth satellite is successful or the system determines the attitude and the position of the first low-earth satellite or the aircraft of which the attitude and the position are not determined.

According to a preferred embodiment, after the laser communication link is established between the aerial vehicle and the first low-orbit satellite, the first synchronization satellite maintains the laser communication link established with the aerial vehicle and/or the first low-orbit satellite until the data transmission between the aerial vehicle and the first low-orbit satellite is completed, and the first synchronization satellite identifies a link state of the laser communication link established between the aerial vehicle and the first low-orbit satellite and a transmission state of the data transmitted through the laser communication link, and in the case where the transmission state is an uncompleted state and the link state is an unavailable state, the first synchronization satellite transmits a request for assistance in transmitting the data to the aerial vehicle and the first low-orbit satellite, and after both the aerial vehicle and the first low-orbit satellite receive the request for assistance in transmitting the data transmitted by the first synchronization satellite, the aerial vehicle and the first low-orbit satellite transmit the data through the laser communication link established between the aerial vehicle and the first synchronization satellite and the laser communication link established by the first synchronization satellite and the first low-orbit satellite The optical communication link indirectly transfers data.

According to a preferred embodiment, when the aircraft and the first low-earth orbit satellite directly transmit data through the laser communication link established between the aircraft and the first low-earth orbit satellite, the data is transmitted in clear or encrypted by using a first encryption algorithm; and/or when the aircraft and the first low-orbit satellite transmit data through the laser communication link established by the aircraft and the first synchronous satellite and the laser communication link established by the first synchronous satellite and the first low-orbit satellite, encrypting the transmitted data by adopting a second encryption algorithm different from the first encryption algorithm; wherein the key used to encrypt the data for the first encryption algorithm and/or the second encryption algorithm is transmitted directly over the laser communication link established between the aerial vehicle and the first low-earth satellite when the link state of the laser communication link established between the aerial vehicle and the first low-earth satellite is in an available state.

According to a preferred embodiment, after the laser communication link is established between the aircraft and the first low-orbit satellite and before the data to be encrypted is transmitted, the aircraft and the first low-orbit satellite need to perform a key generation process and a key transmission process; the key generation process comprises the following steps: the aircraft or the first low orbit satellite generates a symmetric key for the first encryption algorithm, the aircraft generates a first asymmetric key for the second encryption algorithm, the first low orbit satellite generates a second asymmetric key for the second encryption algorithm, the first asymmetric key comprises a first public key and a first private key, and the second asymmetric key comprises a second public key and a second private key; the key transmission process comprises the following steps: the aircraft or the first low-orbit satellite transmits the generated symmetric key to the first low-orbit satellite or the aircraft through a laser communication link established between the aircraft and the first low-orbit satellite, the aircraft transmits the generated first public key to the first low-orbit satellite through a laser communication link established between the aircraft and the first low-orbit satellite, and the first low-orbit satellite transmits the generated second public key to the aircraft through a laser communication link established between the aircraft and the first low-orbit satellite.

According to a preferred embodiment, the aircraft is configured to: generating at least two symmetric keys corresponding to at least two security levels and generating at least two groups of first asymmetric keys corresponding to the at least two security levels, wherein the symmetric keys or the first asymmetric keys with higher security levels are distributed with longer key lengths, before the aircraft transmits data to the first low-orbit satellite through a laser communication link established between the aircraft and the first low-orbit satellite, the aircraft determines the security level required for transmitting the data to the first low-orbit satellite, and selects the keys required for encrypting the data according to the security level determined by the aircraft and required for transmitting the data to the first low-orbit satellite; and/or the first low earth satellite is configured to: generating at least two sets of second asymmetric keys corresponding to at least two security levels, the second asymmetric keys with higher security levels being assigned longer key lengths, the first low-orbit satellite determining a security level required for transmitting data to the aircraft before the first low-orbit satellite transmits data to the aircraft via the laser communication link established between the aircraft and the first low-orbit satellite, and selecting the key required for encrypting the data according to the security level determined by the first low-orbit satellite for transmitting data to the aircraft.

According to a preferred embodiment, the aircraft is configured to: after selecting a key required for encrypting data according to the determined security level required for transmitting the data to the first low-orbit satellite and before transmitting the encrypted data to the first low-orbit satellite, transmitting the security level required for transmitting the data to the first low-orbit satellite determined by the aircraft to enable the first low-orbit satellite to enable a decryption key adapted thereto; and/or the first low earth satellite is configured to: after selecting the key required for encrypting the data according to the determined security level required for transmitting the data to the aircraft and before transmitting the encrypted data to the aircraft, the security level determined by the first low earth orbit satellite required for transmitting the data to the aircraft is transmitted to the aircraft to enable the aircraft to use the decryption key adapted thereto.

According to a preferred embodiment, the aircraft is further configured to: before the aircraft sends the determined security level required for transmitting data to the first low-orbit satellite, the first private key corresponding to the highest security level generated by the aircraft and the second public key corresponding to the highest security level generated by the first low-orbit satellite are used for encrypting the security level required for transmitting data to the first low-orbit satellite determined by the aircraft and then sending the encrypted security level to the first low-orbit satellite; and/or the first low earth satellite is further configured to: before the first low-orbit satellite sends the determined security level required for transmitting data to the aircraft, the second private key corresponding to the highest security level generated by the first low-orbit satellite and the first public key corresponding to the highest security level generated by the aircraft are used for encrypting the security level required for transmitting data to the aircraft and determined by the first low-orbit satellite, and then the encrypted security level is sent to the aircraft.

According to a preferred embodiment, the aircraft is further configured to: decrypting the security level determined by the received first low-orbit satellite and required for transmitting data to the aircraft by using a first private key which is generated by the aircraft and corresponds to the highest security level and a second public key which is generated by the first low-orbit satellite and corresponds to the highest security level, and enabling a decryption secret key adapted to the first private key to decrypt the corresponding data transmitted by the first low-orbit satellite; and/or the first low earth satellite is further configured to: and decrypting the security level determined by the received aircraft and required for transmitting the data to the first low-orbit satellite by using the second private key which is generated by the first low-orbit satellite and corresponds to the highest security level and the first public key which is generated by the aircraft and corresponds to the highest security level, and enabling the decryption key adapted to the second private key to decrypt the corresponding data transmitted by the aircraft.

Drawings

Fig. 1 is a simplified schematic diagram of a preferred embodiment of the present invention.

List of reference numerals

100: the aircraft 110: first ATP device

120: third ATP device 210: first low earth orbit satellite

211: second ATP device 212: fourth ATP device

310: the first sync satellite 320: second geostationary satellite

400: the ground station 410: microwave station

420: optical station

Detailed Description

This is explained in detail below with reference to fig. 1.

In the description of the present invention, it is to be understood that the terms "first", "second", and the like, if any, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, the term "plurality", if any, means two or more unless specifically limited otherwise.