Disclosure of Invention
Therefore, in order to solve the above technical problems, it is necessary to provide a general method for designing a satellite internet system, which can reduce the frequency resources occupied by the system while ensuring the global coverage capability of the system.
A satellite internet system design method based on a space-frequency hybrid multiple access mode comprises the following steps:
and determining the orbital altitude parameter of the satellite according to the altitude of the space particle radiation zone and the preset system performance requirement. The performance requirements include ground coverage capability, satellite-to-ground communication link delay, and satellite carrying capability.
And acquiring a satellite multi-beam antenna coverage field angle alpha of the satellite, and acquiring satellite orbit quantity parameters and satellite quantity parameters required by all satellites in the system to cover the whole world according to the determined satellite orbit height parameters and the acquired satellite multi-beam antenna coverage field angle.
The arrangement of sub-beams of a multi-beam antenna of a satellite is set. And obtaining the sub-beam quantity parameter and the sub-beam coverage field angle parameter of the satellite multi-beam antenna according to the set arrangement mode and the obtained satellite multi-beam antenna coverage field angle alpha.
And according to the set sub-beam arrangement mode and the sub-beam quantity parameters, obtaining the receiving and transmitting frequency band parameters and the frequency multiplexing times parameters of the system under the condition that the receiving and transmitting frequency band parameters of the adjacent sub-beams are different and are not overlapped. The transmission/reception band parameter refers to the number of transmission/reception bands used by the system and the frequency range value of each transmission/reception band. The frequency reuse number parameter indicates the number of frequency range values of the transceiving frequency band occupied by one satellite multi-beam antenna.
In one embodiment, the method further comprises the following steps: the sub-beam arrangement is set to a honeycomb arrangement. The cellular arrangement of the sub-beams may be described as: the center of 6n sub-beams of the nth turn arranged around the central sub-beam is deviated from the star-ground line by an inclination angle n x beta with respect to a sub-beam pointing to the earth center, and the azimuth angles are sequentially [60 °/n, 120 °/n, 180 °/n, … …, 60 ° × i/n ], i is 1, 2, 3, … …, 6 n. Wherein N is 1, 2, 3, … …, N is an integer value determined according to the multi-beam antenna coverage opening angle α and the sub-beam coverage opening angle parameter, β is the tilt angle of the sub-beam of the 1 st circle, β is smaller than the sub-beam coverage opening angle parameter, and β × (2N +1) ≧ α.
In one embodiment, the method further comprises the following steps: and determining the satellite orbit height parameters as high-inclination orbits, including polar orbits with an inclination angle of 90 degrees. The advantages of using high-dip-angle orbit include stable illumination condition of the system, covering all the orbits by establishing a single ground station in polar regions, more convenient later-stage constellation deployment and upgrade of the system, and the like.
In one embodiment, the method further comprises the following steps: under the condition of ensuring the global coverage of the system and not generating communication interference, the number of the obtained transmitting and receiving frequency bands of the system is more than 8.
In one embodiment, the method further comprises the following steps: setting an operation strategy of the satellite Internet system, wherein the operation strategy can be described as follows: according to another embodiment, the cellular arrangement divides the sub-beams into M sub-beam groups, the 1 st group of sub-beams being a center sub-beam of the cellular arrangement of sub-beams, and the M-th group of sub-beams being a sub-beam of an n-th turn of the cellular arrangement of sub-beams. Wherein M is 2, 3, … …, M, and M is n + 1. The satellite orbit is divided into P regions according to the phase difference values. The phase difference value is a phase difference between the current position of the satellite and the closest intersection point of the orbit, and ranges from 0 ° to 90 °. The 1 st area includes a track section having a phase difference of 0 °, and the P-th area includes a track section having a phase difference of 90 °. When the satellite operates in the p-th area, the multi-beam antenna of the satellite turns on the 1 st to m-th sub-beam groups and turns off the rest of the sub-beams, wherein p is m.
In one embodiment, the method further comprises the following steps: when the multi-beam antenna coverage opening angle alpha of the acquired satellite is 64 degrees, determining the optimized parameters of the satellite internet system, wherein the parameters comprise 17 orbit number parameters and 578 satellite number parameters.
A satellite internet system design device based on a space-frequency hybrid multiple access mode comprises a constellation design module, a single satellite beam design module and a multiple access mode design module.
The constellation design module is used for determining the orbit height parameter of the satellite according to the space particle radiation zone height and the preset system performance requirements such as the ground coverage capability, the satellite-ground communication link delay, the satellite carrying capability and the like. And the system is also used for acquiring the satellite multi-beam antenna coverage field angle alpha and acquiring satellite orbit quantity parameters and satellite quantity parameters required by all satellites in the system to cover the whole world according to the determined satellite orbit altitude parameters and the acquired satellite multi-beam antenna coverage field angle.
The single satellite beam design module is used for setting a sub-beam arrangement mode of a multi-beam antenna of the satellite, and obtaining a sub-beam quantity parameter and a sub-beam coverage field angle parameter of the multi-beam antenna according to the set arrangement mode and a multi-beam antenna coverage field angle alpha of the satellite;
the multiple access mode design module is used for obtaining the receiving and transmitting frequency band parameters and the frequency multiplexing times parameters of the system according to the sub-beam arrangement mode and the sub-beam quantity parameters under the condition that the receiving and transmitting frequency band parameters of the adjacent sub-beams are different and are not overlapped. The receiving and transmitting frequency band parameters comprise the number of the receiving and transmitting frequency bands and the frequency range value of each receiving and transmitting frequency band; the frequency reuse number parameter indicates the number of frequency range values of the transceiving frequency band occupied by one satellite multi-beam antenna.
In one embodiment, the single satellite beam design module of the apparatus further includes a cellular arrangement design module, configured to set the sub-beams of the multi-beam antenna to be in a cellular arrangement. The specific arrangement can be described as follows: the center of 6n sub-beams of the nth turn arranged around the central sub-beam is deviated from the star-ground line by an inclination angle n x beta with respect to a sub-beam pointing to the earth center, and the azimuth angles are sequentially [60 °/n, 120 °/n, 180 °/n, … …, 60 ° × i/n ], i is 1, 2, 3, … …, 6 n. Wherein N is 1, 2, 3, … …, N is an integer value determined according to the multi-beam antenna coverage opening angle α and the sub-beam coverage opening angle parameter, β is the tilt angle of the sub-beam of the 1 st circle, β is smaller than the sub-beam coverage opening angle parameter, and β × (2N +1) ≧ α.
In one embodiment, the orbit height parameter of the constellation set by the constellation design module of the device is a high dip orbit, including a polar orbit with a dip angle of 90 °.
In one embodiment, the apparatus further comprises an operation policy module for setting an operation policy of the satellite internet system. The operating strategy may be described as: according to another embodiment, the cellular arrangement divides the sub-beams into M sub-beam groups, the 1 st group of sub-beams being a center sub-beam of the cellular arrangement of sub-beams, and the M-th group of sub-beams being a sub-beam of an n-th turn of the cellular arrangement of sub-beams. Wherein M is 2, 3, … …, M, and M is n + 1. The satellite orbit is divided into P regions according to the phase difference values. The phase difference value is a phase difference between the current position of the satellite and the closest intersection point of the orbit, and ranges from 0 ° to 90 °. The 1 st area includes a track section having a phase difference of 0 °, and the P-th area includes a track section having a phase difference of 90 °. When the satellite operates in the p-th area, the multi-beam antenna of the satellite turns on the 1 st to m-th sub-beam groups and turns off the rest of the sub-beams, wherein p is m.
For specific limitations of a satellite internet system design apparatus based on a space-frequency hybrid multiple access method, refer to the above limitations on a satellite internet system design method based on a space-frequency hybrid multiple access method, which are not described herein again. All or part of the modules in the satellite internet system design device based on the space-frequency hybrid multiple access mode can be realized by software, hardware and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.
The method and the device for designing the satellite internet system based on the space-frequency hybrid multiple access mode consider the influence of space particle radiation band and other operation environment factors, and determine the satellite orbit height according to the performance requirements of the system on the ground coverage capacity, the satellite-ground communication link, the satellite carrying capacity, the carrying opportunity and the like; parameters such as satellite orbit, satellite quantity and the like of the system are obtained according to the orbit height and the satellite antenna parameters, and the global coverage capability of the system is ensured; according to the arrangement mode of the sub-beams, the same frequency is repeatedly used on the non-adjacent sub-beams by utilizing the space division multiple access technology, so that the frequency resource amount occupied by the system is reduced, and the communication capacity of the system can be improved.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
With the development of satellite communication technology and the reduction of satellite manufacturing and launching costs, low-orbit satellites are becoming the mainstream platform of the satellite internet system. The satellite system has the advantages of large communication capacity, small communication delay, good communication effect and the like. In order to adapt to the characteristics of large satellite quantity, large orbit quantity, global deployment application and the like of the system, the system design must ensure the global coverage capability of the system and simultaneously reduce the frequency resource quantity occupied by the system as much as possible so as to reduce the difficulty of global deployment of the system. Possible techniques include reusing frequency resources using multiple access techniques such as space division multiple access, frequency division multiple access, etc., and avoiding overlapping frequencies of adjacent beams in the system.
The invention provides a satellite internet system design method based on a space-frequency hybrid multiple access mode, which comprises the following specific steps as shown in figure 1:
step 102: and determining the orbital altitude parameter of the satellite according to the altitude of the space particle radiation zone and the preset system performance requirement.
The performance requirements include ground coverage capability, satellite-to-ground communication link delay, and satellite carrying capability. The space particle radiation zone is a high-energy particle radiation zone surrounding the earth in a near-layer space near the earth, the latitude range of the radiation zone is generally considered to be between 40 degrees and 50 degrees of north and south latitude, and the height range is divided into two sections, namely an inner zone 1500-5000 km and an outer zone 13000-20000 km. Since the space particle radiation zone may adversely affect devices such as chips of the satellite, thereby reducing the performance of the satellite and even affecting the operation safety thereof, various satellite systems should avoid the space particle radiation zone when selecting the orbit.
Step 104: and acquiring a satellite multi-beam antenna coverage field angle alpha of the satellite, and acquiring satellite orbit quantity parameters and satellite quantity parameters required by all satellites in the system to cover the whole world according to the determined satellite orbit height parameters and the acquired satellite multi-beam antenna coverage field angle.
Step 106: the arrangement of sub-beams of a multi-beam antenna of a satellite is set. And obtaining the sub-beam quantity parameter and the sub-beam coverage field angle parameter of the satellite multi-beam antenna according to the set arrangement mode and the obtained satellite multi-beam antenna coverage field angle alpha.
Step 108: and according to the set sub-beam arrangement mode and the sub-beam quantity parameters, obtaining the receiving and transmitting frequency band parameters and the frequency multiplexing times parameters of the system under the condition that the receiving and transmitting frequency band parameters of the adjacent sub-beams are different and are not overlapped.
The transmission/reception band parameter refers to the number of transmission/reception bands used by the system and the frequency range value of each transmission/reception band. The frequency reuse number parameter indicates the number of frequency range values of the transceiving frequency band occupied by one satellite multi-beam antenna.
In one embodiment, the method further comprises the following steps: setting the sub-beam arrangement as a cellular arrangement, setting the multi-beam antenna field angle of a single satellite as α, using 19 sub-beams in the single satellite coverage area of the ground antenna, and performing cellular arrangement on the sub-beams, where the coverage area of each sub-beam is referred to as a cell, as shown in fig. 2 and 3. The cellular arrangement of the sub-beams may be described as: taking N as 2; centering on a sub-beam pointing to the geocentric; when n is 1, the center of the 6 sub-beams of the 1 st turn arranged around the central sub-beam deviates from the star-ground line by an inclination angle of beta, and the azimuth angles are sequentially [60 degrees, 120 degrees, 180 degrees, 240 degrees, 300 degrees, 360 degrees ]; when n is 2, the center of the 12 sub-beams of the 2 nd turn is deviated from the star-ground connection line by an inclination angle of 2 β, and the azimuth angles are [30 °, 60 °, 90 °, 120 °, 150 °, 180 °, 210 °, 240 °, 270 °, 300 °, 330 °, 360 ° ], in sequence. Wherein beta is less than the sub-beam coverage field angle parameter, and 5 beta is more than or equal to alpha. The system of the present embodiment is optimally designed in a ground coverage manner as shown in fig. 4.
In one embodiment, the method further comprises the following steps: and determining the satellite orbit height parameter as a high-inclination orbit. The advantages of using high-dip-angle orbit include stable illumination condition of the system, covering all the orbits by establishing a single ground station in polar regions, more convenient later-stage constellation deployment and upgrade of the system, and the like.
Further, an operation policy of the satellite internet system is set, as shown in fig. 5. The operation strategy of the satellite internet system can be described as follows: according to another embodiment, the honeycomb arrangement is implemented by dividing the sub-beams into 3 sub-beam groups, where N is 2 and M is 3; when m is 1, the 1 st group of sub-beams is a central sub-beam of the honeycomb arrangement sub-beams; when m is 2, the 2 nd sub-beam group is a sub-beam of the 1 st turn of the honeycomb arrangement sub-beam; when m is 3, the 3 rd sub-beam group is the sub-beam of the 2 nd turn of the honeycomb arrangement sub-beam. The satellite orbit is divided into 3 regions according to the phase difference values. The phase difference value is a phase difference between the current position of the satellite and the closest intersection point of the orbit, and ranges from 0 ° to 90 °. The 1 st area includes track sections having a phase difference of 0 °, and the 3 rd area includes track sections having a phase difference of 90 °. When the satellite operates in the 1 st area, the multi-beam antenna of the satellite turns on the 1 st sub-beam group and turns off the rest sub-beams; when the satellite operates in the 2 nd area, the multi-beam antenna of the satellite turns on the 1 st and 2 nd sub-beam groups and turns off the rest sub-beams; when the satellite is operating in region 3, the satellite's multi-beam antenna turns on sub-beam sets 1 st, 2 nd and 3 rd.
Furthermore, when the satellite orbit is polar orbit, the overlapping range between the coverage areas of the satellite is increased continuously when the satellite moves towards the direction close to the polar region, which is easy to cause signal interference. Therefore, when the satellite moves towards the direction close to the polar region, the following operation strategy is adopted according to the latitude of the subsatellite point: taking P as M as 3; when p is 1, the 1 st area is an interval with the phase difference value of 0-15 degrees, and when the satellite is in the area, only the 1 st sub-beam group, namely the central beam, is switched on; when p is 2, the 2 nd area is an interval with the phase difference value of 15 degrees to 35 degrees, and when the satellite is in the area range, the 1 st and 2 nd sub-beam group central beams are started; when p is 3, the 3 rd region is in the interval of 35 ° to 90 °, and all 3 sub-beam groups are turned on.
Furthermore, the system adopts 8 frequency bands, the bandwidth of each frequency band is 50MHz, and the communication capacity of the whole system can reach 385 Gbps.
In one embodiment, the method further comprises the following steps: under the condition of ensuring the global coverage of the system and not generating communication interference, the number of the obtained transmitting and receiving frequency bands of the system is more than 8.
Furthermore, because the satellite coverage areas on the adjacent orbital planes also have overlapping parts, different receiving and transmitting frequency band parameters are adopted for the satellites on the adjacent orbital planes in order to avoid the interference of the satellite coverage areas of the adjacent orbital planes. That is, the whole system adopts 2 groups of 4 frequency bands and 8 frequency bands to realize inter-satellite frequency multiplexing so as to ensure beam isolation. The frequency multiplexing method of this embodiment is shown in fig. 6.
Further, the spacing between the bands is 50 MHz.
Furthermore, the frequency bandwidth and the interval between frequency bands can be further reduced by adopting a high-order modulation mode.
In one embodiment, the method further comprises the following steps: when the coverage field angle alpha of the multi-beam antenna for obtaining the satellite is 64 degrees, factors such as ground coverage capacity, satellite-ground communication links, carrying capacity and carrying opportunities, space particle radiation bands and the like are comprehensively considered, the height of a track is selected to be 1200km, and optimization parameters of the satellite internet system are determined, wherein the optimization parameters comprise: the number parameter of the tracks is 17, and all the track surfaces are uniformly distributed; 34 satellites are uniformly distributed on each orbit, the phase difference between the satellites in the adjacent orbits is 1/2, namely 5.29 degrees, of the phase difference between the satellites in the same orbit, and the quantity parameter of the satellites of the system is 578. The partial and overall schematic diagrams of the optimally designed constellation of the present embodiment are shown in fig. 7 and fig. 8, respectively.
Further, according to the honeycomb arrangement in another embodiment: the coverage field angle alpha of the satellite multi-beam antenna is 64 degrees, N is 2, M is 3, 19 sub-beams are used in the coverage area of a satellite single satellite, the coverage field angle parameter of the obtained sub-beams is 14 degrees, and according to the value range requirement of beta, the inclination angle beta of the center of the 1 st circle of 6 sub-beams arranged around the center sub-beam deviating from the satellite-ground connecting line is optimally selected to be 13 degrees. The single-beam antenna gain of about 21dBi (antenna efficiency of 0.55) can be calculated according to the relationship between the beam angle and the antenna gain. The coverage area of a single sub-beam to the ground is a circle with the radius of about 150km (the coverage area of the edge beam is elliptical and has a slightly larger area). The single beam coverage area is 7.0 kilo square kilometers; the single star coverage area is about 130 kilo-square kilometers.
In one embodiment, for a single satellite, the same frequency is allocated to non-adjacent sub-beams by using the space division multiple access technology of angle diversity, so that the frequency utilization rate is improved, and the requirement of avoiding interference between the beams is met. In addition, the angle classification technology can improve the communication capacity of the whole network on the premise of not increasing the bandwidth. In order to reduce the interference between the co-channel beams, 4 different frequencies are adopted in the same satellite coverage area, namely f1, f2, f3 and f4, and the frequency reuse time K is 4. The number of transmission/reception bands and the number of frequency reuse times for a single satellite are shown in fig. 9.
Further, the orbit height is 1200km and polar orbits are selected, and the cell center distance (near the equator) of the same frequency is calculated by the formula (2):
where R is the radius of the coverage cell, and D is 520 km.
Further, the sub-beam bands of adjacent satellites located in the same orbit are staggered as shown in fig. 10.
A satellite internet system design device based on a space-frequency hybrid multiple access mode comprises a constellation design module, a single satellite beam design module and a multiple access mode design module.
The constellation design module is used for determining the orbit height parameter of the satellite according to the space particle radiation zone height and the preset system performance requirements such as the ground coverage capability, the satellite-ground communication link delay, the satellite carrying capability and the like. And the system is also used for acquiring the satellite multi-beam antenna coverage field angle alpha and acquiring satellite orbit quantity parameters and satellite quantity parameters required by all satellites in the system to cover the whole world according to the determined satellite orbit altitude parameters and the acquired satellite multi-beam antenna coverage field angle.
The single satellite beam design module is used for setting a sub-beam arrangement mode of a multi-beam antenna of the satellite, and obtaining a sub-beam quantity parameter and a sub-beam coverage field angle parameter of the multi-beam antenna according to the set arrangement mode and a multi-beam antenna coverage field angle alpha of the satellite;
the multiple access mode design module is used for obtaining the receiving and transmitting frequency band parameters and the frequency multiplexing times parameters of the system according to the sub-beam arrangement mode and the sub-beam quantity parameters under the condition that the receiving and transmitting frequency band parameters of the adjacent sub-beams are different and are not overlapped. The receiving and transmitting frequency band parameters comprise the number of the receiving and transmitting frequency bands and the frequency range value of each receiving and transmitting frequency band; the frequency reuse number parameter indicates the number of frequency range values of the transceiving frequency band occupied by one satellite multi-beam antenna.
In one embodiment, the method further comprises the following steps: the single satellite beam design module also comprises a honeycomb arrangement mode design module which is used for setting the sub-beams of the multi-beam antenna into a honeycomb arrangement mode. The specific arrangement can be described as follows: the center of 6n sub-beams of the nth turn arranged around the central sub-beam is set to be deviated from the star-ground line by an inclination angle of n x beta with respect to a sub-beam directed to the center of the earth as the center, and the azimuth angles are sequentially [60 °/n, 120 °/n, 180 °/n, … …, 60 ° × i/n ], i ═ 1, 2, 3, … …, 6 n. Wherein N is 1, 2, 3, … …, N is an integer value determined according to the multi-beam antenna coverage opening angle α and the sub-beam coverage opening angle parameter, β is the tilt angle of the sub-beam of the 1 st circle, β is smaller than the sub-beam coverage opening angle parameter, and β × (2N +1) ≧ α.
In one embodiment, the orbit height parameter of the constellation set by the constellation design module of the device is a high dip orbit, including a polar orbit with a dip angle of 90 °.
In one embodiment, the apparatus further comprises an operation policy module for setting an operation policy of the satellite internet system. The operating strategy may be described as: according to another embodiment, the cellular arrangement divides the sub-beams into M sub-beam groups, the 1 st group of sub-beams being a center sub-beam of the cellular arrangement of sub-beams, and the M-th group of sub-beams being a sub-beam of an n-th turn of the cellular arrangement of sub-beams. Wherein M is 2, 3, … …, M, and M is n + 1. The satellite orbit is divided into P regions according to the phase difference values. The phase difference value is a phase difference between the current position of the satellite and the closest intersection point of the orbit, and ranges from 0 ° to 90 °. The 1 st area includes a track section having a phase difference of 0 °, and the P-th area includes a track section having a phase difference of 90 °. When the satellite operates in the p-th area, the multi-beam antenna of the satellite turns on the 1 st to m-th sub-beam groups and turns off the rest of the sub-beams, wherein p is m.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.