A satellite-borne device suitable for full-duplex satellite communication

Abstract

The present invention discloses a satellite-borne device suitable for full-duplex satellite communication, belonging to the field of satellite-borne technology for satellite communication. The present invention sets two support arms at both ends of the satellite platform, and carries a transmitting antenna and a plurality of receiving antennas for satellite full-duplex communication at both ends of the support arms. The electromagnetic signal of the ground node is approximately a plane wave and vertically incident on the receiving antenna on the support arm. The distance from the receiving antenna to the transmitting antenna satisfies that the sum of the self-interference signals received by the multiple receiving antennas cancel each other out. The present invention suppresses and cancels the full-duplex self-interference signal without affecting the antenna directivity, thereby improving the spectrum efficiency of full-duplex communication.

Description

Technical Field

[0001] The patent of this invention is a technical solution for mounting a satellite antenna suitable for full-duplex satellite communication scenarios, involving a new satellite antenna mounting device, and belongs to the field of satellite antennas. Background Art

[0002] Satellite communication is an important method to solve the problem of communication signal coverage in remote areas around the world, and can effectively avoid signal blind spots caused by difficult base station deployment. There are few obstructions in the communication link between the satellite and the ground receiving node, and signal transmission is not easily interfered with. Due to the high satellite orbit, the area covered by a single satellite communication is also very considerable, which is an effective solution to solve the communication problems in vast areas that have not yet been included in the ground communication network. Full-duplex satellite communication uses full-duplex self-interference elimination technology to eliminate the self-interference of the transmitting antenna to the receiving antenna when the satellite and the ground communicate at the same frequency at the same time, so as to achieve correct reception and decoding of effective signals. Compared with traditional half-duplex satellite communication technology, the spectrum efficiency is increased by nearly 2 times, and the satellite communication capability is enhanced. Existing satellite communication solutions usually consider the half-duplex mode, focusing more on ensuring the coverage area, weight and whether the antenna is convenient to deploy. The design of the antenna-mounted technical solution does not consider the impact of eliminating the simultaneous self-interference signals at the same frequency, and is not suitable for full-duplex satellite communication. Summary of the invention

[0003] In order to solve the problem of eliminating self-interference of onboard antennas in full-duplex satellite communications, the present invention provides a onboard antenna mounting device suitable for full-duplex satellite communications, which ensures the coverage area of ​​the communication satellite while ensuring less interference between onboard transmitting and receiving antennas.

[0004] The technical solution of the present invention is:

[0005] A satellite-borne device suitable for full-duplex satellite communication, characterized in that two support arms are arranged at both ends of a satellite platform, a straight line formed by the two support arms and a straight line formed by two solar panels of the satellite platform are in the same plane and perpendicular, a transmitting antenna and a plurality of receiving antennas for satellite full-duplex communication are carried at both ends of the support arms, an electromagnetic signal of a ground node is approximately a plane wave and vertically incident on the receiving antenna on the support arm, the receiving signals received by all the receiving antennas are in the same direction, and the distance from the receiving antenna to the transmitting antenna satisfies that the sum of the self-interference signals received by the multiple receiving antennas cancel each other out, thereby achieving self-interference suppression, which is expressed as:

[0006]

[0007] where d i(i=1, 2, 3, . . . n) are the distances between the multiple receiving antennas and the transmitting antenna, λ is the wavelength of the single-frequency signal used for communication, and n is the number of receiving antennas.

[0008] The length of the support arm is equal to the length of the satellite solar sail panel.

[0009] Furthermore, a rotating component is provided between the support arm and the satellite platform, and the orientation of the satellite-borne antenna is adjusted by rotating the support arm, thereby adjusting the antenna coverage when communicating with the ground node.

[0010] Furthermore, since the self-interference paths in space basically only exist in the direct path and the reflected multipath passing through the satellite platform, absorbing materials can be set on the surface of the support arm to achieve further attenuation of the self-interference signal.

[0011] Furthermore, the satellite-borne antenna for full-duplex communication uses a high-gain parabolic antenna or a microstrip antenna, which not only ensures the high gain of satellite-to-ground communication, but also reduces the self-interference signal strength caused by sidelobe leakage, thereby improving the quality of full-duplex communication. However, such antennas are often large in size, and the support arm of the present invention can solve the defect of being inconvenient to install.

[0012] The polarization modes of the transmitting antenna and the receiving antenna are selected to be horizontal polarization, vertical polarization, or left-hand polarization, right-hand polarization.

[0013] In the present invention, since the support arm and the solar panel are perpendicular to each other, the solar panel receiving energy and the satellite antenna communication will not be affected by the satellite attitude and orbital position. In order to achieve full-duplex communication, and the distance between the two ends of the support arm is far, the transmitting and receiving antennas are placed at the two ends of the support arm to achieve a certain antenna isolation, and the intensity of the self-interference signal reaching the receiving antenna through path loss will be reduced. At the same time, the antenna fixed on the support arm has a less multipath content in the communication channel between the satellite-borne transceiver and the receiver, which is suitable for polarization interference elimination. The polarization mode of the transceiver antenna can be selected as horizontal, vertical polarization or left-handed, right-handed polarization, and the polarization orthogonal characteristics of the electromagnetic signal are used to eliminate self-interference; for the self-interference problem between the satellite-borne transceiver antennas, the present invention maximizes the distance between the two antennas by arranging the antenna in the same plane and perpendicular to the solar panel, and realizes the suppression of the self-interference signal. While achieving less interference between the satellite-borne transceiver antennas, the present invention ensures that the direction of the antenna can be freely changed no matter how the solar panel rotates, thereby ensuring the coverage area of ​​the communication satellite. The antenna is arranged in the vertical direction of the solar panel, which also effectively reduces the generation of multipath and provides favorable conditions for the subsequent elimination of interference in the analog and digital domains.

[0014] The advantages of the present invention compared with the prior art are:

[0015] (1) An antenna mounting device suitable for full-duplex satellite communication is proposed. A support arm is added perpendicular to the direction of the solar panel to fix the satellite-borne antenna, which increases the distance between the transmitting and receiving antennas, which is conducive to the elimination of full-duplex self-interference. The antenna is always facing the ground, avoiding the impact of solar panel movement and satellite attitude changes on coverage area and communication quality.

[0016] (2) The technical solution of using vertical support arms can configure the antenna with high flexibility and can support a variety of full-duplex self-interference elimination and suppression methods such as antenna isolation, highly directional antennas, antenna polarization small interference, and antenna position-based cancellation.

[0017] (3) The present invention has a simple structure, a feasible method and high flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a schematic diagram of realizing satellite-to-ground full-duplex communication.

[0019] Among them: 1. Satellite platform; 2. Solar panels; 3. Support arm; 4. Satellite antenna; 5. Ground antenna;

[0020] Figure 2 Schematic diagram of antenna positions in a specific implementation manner of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below by way of embodiments in conjunction with the accompanying drawings, but the scope of the present invention is not limited in any way.

[0022] The technical key point of full-duplex satellite communication is self-interference elimination, such as Figure 1 As shown, the present invention sets two support arms at both ends of the satellite platform, and the straight line formed by the two support arms and the straight line formed by the two solar panels of the satellite platform are in the same plane and perpendicular. A transmitting antenna and several receiving antennas for satellite full-duplex communication are carried at both ends of the support arms. The electromagnetic signal of the ground node is approximately a plane wave and is vertically incident on the receiving antenna on the support arm, and the receiving signals received by all receiving antennas are in the same direction. Among them, the support arm structure can increase the selection range of the antenna, and the installation is also more convenient, supporting the use of a larger high-gain parabolic antenna. At the same time, since there is almost no obstruction on the support arm except the antenna, the satellite-borne antenna can be used to adopt left-handed and right-handed circular polarization respectively, and the orthogonality of the polarization direction can be used to eliminate self-interference. However, there are many obstructions between traditional satellite-borne antennas, and multipath has a greater impact on the polarization direction, so the polarization interference elimination method is not suitable.

[0023] When the support arm structure is equipped with an antenna, the transmitting antenna and the receiving antenna can be pulled as far apart as possible, and the path loss generated by antenna isolation can be used to eliminate the self-interference signal. According to the free space loss model, the self-interference signal suppression obtained by antenna isolation is:

[0024] Los=32.44+20lg d(km)+20lg f(MHz)

[0025] Wherein, d represents the distance between the two antennas, and f represents the frequency of the communication signal. Los represents the path loss caused by antenna isolation, and the unit is dB. It can be seen that the attenuation of the self-interference signal by antenna isolation increases with the increase of distance and frequency. Usually, the frequency of the signal remains unchanged, and the attenuation of the self-interference signal will increase by increasing the distance between the transmitting and receiving antennas. The support arm structure of the present invention has a large size, and compared with the traditional satellite antenna mounting method, the suppression effect of the self-interference signal obtained from antenna isolation is better.

[0026] The distance from the receiving antenna to the transmitting antenna satisfies that the sum of the self-interference signals received by the multiple receiving antennas cancels each other out, thereby suppressing the self-interference, which is expressed as:

[0027]

[0028] The present invention takes the example of Globalstar satellite using Band n53 (2483.5-2495MHz) frequency to provide satellite communication services to iPhone mobile phones. Figure 2 As shown, it is assumed that a transmitting antenna and two receiving antennas are fixedly placed on the supporting arm, the length of both ends of the supporting arm is L=20m, the communication frequency is 2.4GHz, and the wavelength λ=12.5cm.

[0029] When the transmitting antenna is between the two receiving antennas, such as Figure 2 As shown in (a), d1 and d2 are the distances from the transmitting antenna to the two receiving antennas, satisfying:

[0030]

[0031] Equivalent to

[0032]

[0033] Among them, λ is the wavelength of the single-frequency signal used for communication, and k=0, 1, 2, 3… is a positive integer. From the above formula, it can be obtained that the two receiving antennas are placed at both ends of the support arm, and the position of the transmitting antenna is determined by d1 and d2, which is expressed as:

[0034]

[0035] Assume that the value range of k that satisfies the above formula is Assume that the path fading from the transmitting antenna to the two receiving antennas is Los1 and Los2, respectively, satisfying:

[0036] Los1=32.44+20lg d1(km)+20lg f(MHz)

[0037] Los2=32.44+20lg d2(km)+20lg f(MHz)

[0038] Therefore, the arrangement method that minimizes the residual self-interference follows:

[0039]

[0040] The residual self-interference is:

[0041]

[0042] When the transmitting antenna is on one side of the two receiving antennas, assuming it is on the left side, such as Figure 2 As shown in (b), d1 and d2 are the distances from the transmitting antenna to the two receiving antennas, respectively, satisfying:

[0043]

[0044] Equivalent to

[0045]

[0046] Among them, λ is the wavelength of the single-frequency signal used for communication, and k=0, 1, 2, 3… is a positive integer. From the above formula, it can be obtained that the transmitting antenna is placed at the leftmost end of the support arm, a receiving antenna is placed at the rightmost end of the support arm, and the position of the other support antenna is determined by d1 and d2, expressed as:

[0047]

[0048] Assume that the value range of k that satisfies the above formula is Assume that the path fading from the transmitting antenna to the two receiving antennas is Los1 and Los2, respectively, satisfying:

[0049] Los1=32.44+20lg d1(km)+20lg f(MHz)

[0050] Los2=32.44+20lg d2(km)+20lg f(MHz)

[0051] Therefore, the arrangement method that minimizes the residual self-interference follows:

[0052]

[0053] The residual self-interference is:

[0054]

[0055] Considering one transmitting antenna and two receiving antennas, the suppression of self-interference signals obtained by antenna isolation can be achieved as follows:

[0056] Los=32.44+20lg 0.02+20lg(2.4×10 3 )≈66.0648dB

[0057] Considering a scheme with one transmitting antenna and two receiving antennas based on antenna position cancellation, the suppression of self-interference signals can be achieved as follows:

[0058]

[0059] Finally, by comparing the two schemes, the placement method with the smallest residual self-interference was selected to configure the satellite antenna on the support arm.

[0060] It should be noted that the purpose of publishing the embodiments is to help further understand the present invention. Those skilled in the art will understand that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the contents disclosed in the embodiments, and the scope of protection claimed in the present invention shall be subject to the scope defined in the claims. The contents not described in detail in the specification of the present invention belong to the common technology of those skilled in the art.

Claims

1. A satellite-borne antenna mounting device suitable for full-duplex satellite communication, characterized in that: Two support arms are set at both ends of the satellite platform. The straight line formed by the two support arms is perpendicular to the straight line formed by the two solar panels of the satellite platform. A transmitting antenna and multiple receiving antennas for satellite full-duplex communication are mounted on the support arms. The electromagnetic signal of the ground node is approximately a plane wave and vertically incident on the receiving antenna on the support arm. The receiving signals received by all receiving antennas are in the same direction. The distance from the receiving antenna to the transmitting antenna satisfies that the sum of the self-interference signals received by the multiple receiving antennas cancels each other, thereby achieving self-interference suppression, which is expressed as: where d i , i=1, 2, 3, ...n, are the distances between the multiple receiving antennas and the transmitting antenna, and λ is the wavelength of the single-frequency signal used for communication.

2. The satellite-borne antenna mounting device suitable for full-duplex satellite communication according to claim 1, characterized in that: The length of the support arm is equal to the length of the satellite solar sail panel.

3. The satellite-borne antenna mounting device suitable for full-duplex satellite communication according to claim 1, characterized in that: A rotating component is arranged between the support arm and the satellite platform, and the direction of the antenna is adjusted by rotating the support arm.

4. The satellite-borne antenna mounting device suitable for full-duplex satellite communication according to claim 1, characterized in that: A wave absorbing material is arranged on the surface of the supporting arm.

5. The satellite-borne antenna mounting device suitable for full-duplex satellite communication according to claim 1, characterized in that: The antenna is a high-gain parabolic antenna or a microstrip antenna.

6. The satellite-borne antenna mounting device suitable for full-duplex satellite communication according to claim 1, characterized in that: The polarization modes of the transmitting antenna and the receiving antenna are selected to be horizontal polarization, vertical polarization, or left-hand polarization, right-hand polarization.

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