阅读说明：本技术 一种Ka频段双模机载宽带卫星通信系统 (Ka frequency band dual-mode airborne broadband satellite communication system ) 是由 杨冬梅 杜凯 于 2021-07-23 设计创作，主要内容包括：本发明涉及一种Ka频段双模机载宽带卫星通信系统,包括显控单元、Ka频段双模宽带卫星通信机载终端和客舱无线局域网系统；所述显控单元连接所述Ka频段双模宽带卫星通信机载终端,用于下发控制指令至所述Ka频段双模宽带卫星通信机载终端；所述Ka频段双模宽带卫星通信机载终端,用于接收所述控制指令,并按照所述控制指令进行操作；所述客舱无线局域网系统连接所述Ka频段双模宽带卫星通信机载终端,用于为乘客提供互联网服务。本发明有效解决国内外航线上的应用需求,实现了多模式工作模块,且天线剖面高、无波束越区切换功能、多普勒适应能力强,设计难度低,市场适应能力较强。(The invention relates to a Ka-band dual-mode airborne broadband satellite communication system, which comprises a display control unit, a Ka-band dual-mode broadband satellite communication airborne terminal and a cabin wireless local area network system, wherein the display control unit is used for displaying a display control signal; the display control unit is connected with the Ka frequency band dual-mode broadband satellite communication airborne terminal and is used for issuing a control instruction to the Ka frequency band dual-mode broadband satellite communication airborne terminal; the Ka frequency band dual-mode broadband satellite communication airborne terminal is used for receiving the control instruction and operating according to the control instruction; the cabin wireless local area network system is connected with the Ka-band dual-mode broadband satellite communication airborne terminal and is used for providing internet service for passengers. The invention effectively meets the application requirements on domestic and foreign airlines, realizes a multi-mode working module, and has the advantages of high antenna profile, no beam handover function, strong Doppler adaptability, low design difficulty and strong market adaptability.)

1. A Ka-band dual-mode airborne broadband satellite communication system is characterized by comprising a display control unit, a Ka-band dual-mode broadband satellite communication airborne terminal and a cabin wireless local area network system;

the display control unit is connected with the Ka frequency band dual-mode broadband satellite communication airborne terminal and is used for issuing a control instruction to the Ka frequency band dual-mode broadband satellite communication airborne terminal;

the Ka frequency band dual-mode broadband satellite communication airborne terminal is used for receiving the control instruction and operating according to the control instruction;

the cabin wireless local area network system is connected with the Ka-band dual-mode broadband satellite communication airborne terminal and is used for providing internet service for passengers.

2. The Ka-band dual-mode airborne broadband satellite communication system according to claim 1, wherein the Ka-band dual-mode airborne broadband satellite communication airborne terminal comprises a Ka-variable polarization flat antenna unit and a modulation and demodulation unit;

the Ka variable polarization panel antenna unit is used for providing wireless signal receiving and transmitting, servo tracking, power amplification, low-noise amplification, Ka up-conversion and Ka down-conversion;

the modulation and demodulation unit is used for receiving signals of the user terminal, processing control protocols and processing data.

3. The Ka band dual mode airborne broadband satellite communication system of claim 1, wherein said cabin wireless local area network system comprises a network server, a wireless access device, and a wireless communication device.

4. The Ka-band dual-mode airborne broadband satellite communication system according to claim 1, wherein the display and control unit is used for providing a man-machine interface, setting system reset, working mode switching and satellite fixed-point position parameters, and displaying a channel and a working state of the Ka-band dual-mode airborne broadband satellite communication terminal.

5. The Ka-band dual-mode airborne broadband satellite communication system according to claim 2, wherein the Ka-variant polarization panel antenna unit comprises an antenna, an antenna control management unit, a transceiving antenna unit, a Ka up-conversion unit and a Ka down-conversion unit.

6. The Ka-band dual-mode airborne broadband satellite communication system according to claim 5, wherein the modem unit is provided with two integrated channel processing modules for accessing an I-5 satellite network and a Midset-16 satellite network respectively;

the working frequency band, the EIRP, the G/T, the polarization mode and the satellite tracking mode of the antenna are respectively matched with the I-5 satellite network and the middle satellite-16 satellite network.

7. The Ka-band dual-mode airborne broadband satellite communication system of claim 6,

the modulation and demodulation unit is used for receiving a mode switching instruction sent by the display and control unit, sending the mode switching instruction to the antenna, activating a comprehensive channel processing module required by the current mode, and controlling an intermediate frequency switching module to switch a receiving and transmitting intermediate frequency signal of the antenna to a corresponding comprehensive channel processing module;

the antenna is used for carrying out polarization and local oscillator switching and starting a satellite tracking process after receiving the called mode switching instruction;

the modulation and demodulation unit is used for calling a special thread and a database resource to assist the antenna to carry out beam switching and inhibit adjacent satellite interference;

the integrated channel processing module is used for starting to receive a forward broadcast signaling issued by a satellite network management center after a wave beam of the antenna is aligned with a satellite, acquiring a working parameter of a current wave beam and sending a network access registration request to the network management center through a return network management channel, and sending a network access confirmation response to the Ka-band dual-mode broadband satellite communication airborne terminal through the forward broadcast channel after the network management center confirms, and the Ka-band dual-mode broadband satellite communication airborne terminal accesses the network after receiving the network access confirmation response.

8. The Ka-band dual-mode airborne broadband satellite communication system according to claim 7, wherein the beam switching comprises switching between adjacent beams under the same satellite, switching between beams of different satellites under the same satellite network, and switching between beams of different satellite networks;

the switching between adjacent beams under the same satellite utilizes beam polarization multiplexing, the antenna re-tracks the satellite after switching the polarization mode, and the modulation and demodulation unit does not switch the comprehensive channel processing module any more;

switching between different satellite beams in the same satellite network, restarting the acquisition and tracking satellite of the antenna according to the new satellite fixed-point position and the polarization parameter, and the modulation and demodulation unit does not switch the comprehensive channel processing module any more;

and switching wave beams among different satellite networks, wherein the antenna retraces the satellite, and the modulation and demodulation unit switches the comprehensive channel processing module.

9. The Ka-band dual-mode airborne broadband satellite communication system of claim 2,

the airborne EIRP of the Ka-band dual-mode broadband satellite communication airborne terminal conforms to the formula:

A_eirp≥E_th+10log(R_rm)-S_gt+L_r+M_r-228.6

wherein A is_eirpIs an airborne EIRP, E_thIs a demodulation threshold, R_rmTo return to the highest traffic rate, S_gtFor satellite transponder G/T value, M_rFor preparation of a balance of engineering, L_rIs the return machine-to-satellite link loss.

10. The Ka-band dual-mode airborne broadband satellite communication system of claim 8,

the modulation and demodulation unit comprises an intermediate frequency exchange module, an I-5 comprehensive channel processing module, a Zhongxing-16 comprehensive channel processing module, a terminal monitoring module, an interface adaptation module, a beam switching module, an information storage module, an interface conversion module and a power supply module.

Technical Field

The invention relates to the technical field of satellite communication, in particular to a Ka-band dual-mode airborne broadband satellite communication system.

Background

With the rapid development of civil aviation market, most passengers hope to obtain broadband internet service similar to the ground in the air for work and entertainment. With the first flight of a domestic C919 large airplane and the emission of a high-flux satellite in a China-16 Ka frequency band, the autonomous design of a cabin broadband satellite communication system is possible, but the following problems still exist: in order to meet the market demands at home and abroad, the system is inevitably required to work in multiple modes, and the design difficulty is higher; the ground fixed satellite communication system is mature in technology due to lack of a proper technical system, but has the problems of high antenna profile, no beam handover function, poor Doppler adaptability and the like, and is difficult to directly apply.

Disclosure of Invention

The invention aims to solve the technical problem of providing a Ka-band dual-mode airborne broadband satellite communication system aiming at the defects of the prior art.

The technical scheme for solving the technical problems is as follows:

a Ka-band dual-mode airborne broadband satellite communication system comprises a display control unit, a Ka-band dual-mode broadband satellite communication airborne terminal and a cabin wireless local area network system;

the display control unit is connected with the Ka frequency band dual-mode broadband satellite communication airborne terminal and is used for issuing a control instruction to the Ka frequency band dual-mode broadband satellite communication airborne terminal;

the Ka frequency band dual-mode broadband satellite communication airborne terminal is used for receiving the control instruction and operating according to the control instruction;

the cabin wireless local area network system is connected with the Ka-band dual-mode broadband satellite communication airborne terminal and is used for providing internet service for passengers.

On the basis of the technical scheme, the invention can be further improved as follows.

Further, the Ka-band dual-mode broadband satellite communication airborne terminal comprises a Ka-variable polarization flat antenna unit and a modulation and demodulation unit;

the Ka variable polarization panel antenna unit is used for providing wireless signal receiving and transmitting, servo tracking, power amplification, low-noise amplification, Ka up-conversion and Ka down-conversion;

the modulation and demodulation unit is used for receiving signals of the user terminal, processing control protocols and processing data.

Further, the cabin wireless local area network system comprises a network server, a wireless access device and a wireless communication device.

Further, the display and control unit is used for providing a man-machine interface, setting system reset, working mode switching and satellite fixed-point position parameters, and displaying a channel and a working state of the Ka-band dual-mode broadband satellite communication airborne terminal.

Furthermore, the Ka-variant polarization panel antenna unit comprises an antenna, an antenna control and management unit, a transceiving antenna unit, a Ka up-conversion unit and a Ka down-conversion unit.

Furthermore, the modulation and demodulation unit is provided with two comprehensive channel processing modules which are respectively accessed to an I-5 satellite network and a China satellite-16 satellite network;

the working frequency band, the EIRP, the G/T, the polarization mode and the satellite tracking mode of the antenna are respectively matched with the I-5 satellite network and the middle satellite-16 satellite network.

Further, the modem unit is configured to receive a mode switching instruction issued by the display control unit, send the mode switching instruction to the antenna, activate a comprehensive channel processing module required by a current mode, and control the intermediate frequency switching module to switch a transmit-receive intermediate frequency signal of the antenna to a corresponding comprehensive channel processing module;

the antenna is used for carrying out polarization and local oscillator switching and starting a satellite tracking process after receiving the called mode switching instruction;

the modulation and demodulation unit is used for calling a special thread and a database resource to assist the antenna to carry out beam switching and inhibit adjacent satellite interference;

the integrated channel processing module is used for starting to receive a forward broadcast signaling issued by a satellite network management center after a wave beam of the antenna is aligned with a satellite, acquiring a working parameter of a current wave beam and sending a network access registration request to the network management center through a return network management channel, and sending a network access confirmation response to the Ka-band dual-mode broadband satellite communication airborne terminal through the forward broadcast channel after the network management center confirms, and the Ka-band dual-mode broadband satellite communication airborne terminal accesses the network after receiving the network access confirmation response.

Further, the beam switching includes switching between adjacent beams under the same satellite, switching between beams of different satellites under the same satellite network, and switching between beams of different satellite networks;

the switching between adjacent beams under the same satellite utilizes beam polarization multiplexing, the antenna re-tracks the satellite after switching the polarization mode, and the modulation and demodulation unit does not switch the comprehensive channel processing module any more;

switching between different satellite beams in the same satellite network, restarting the acquisition and tracking satellite of the antenna according to the new satellite fixed-point position and the polarization parameter, and the modulation and demodulation unit does not switch the comprehensive channel processing module any more;

and switching wave beams among different satellite networks, wherein the antenna retraces the satellite, and the modulation and demodulation unit switches the comprehensive channel processing module.

Further, the airborne EIRP of the Ka-band dual-mode broadband satellite communication airborne terminal conforms to the formula:

A_eirp≥E_th+10log(R_rm)-S_gt+L_r+M_r-228.6

wherein A is_eirpIs an airborne EIRP, E_thIs a demodulation threshold, R_rmTo return to the highest traffic rate, S_gtFor satellite transponder G/T value, M_rFor preparation of a balance of engineering, L_rIs the return machine-to-satellite link loss.

Furthermore, the modulation and demodulation unit comprises an intermediate frequency switching module, an I-5 comprehensive channel processing module, a middle satellite-16 comprehensive channel processing module, a terminal monitoring module, an interface adaptation module, a beam switching module, an information storage module, an interface conversion module and a power supply module.

The method has the beneficial effects that: the Ka-band dual-mode airborne broadband satellite communication system comprises a display control unit, a Ka-band dual-mode broadband satellite communication airborne terminal and a cabin wireless local area network system; the display control unit is connected with the Ka frequency band dual-mode broadband satellite communication airborne terminal and is used for issuing a control instruction to the Ka frequency band dual-mode broadband satellite communication airborne terminal; the Ka frequency band dual-mode broadband satellite communication airborne terminal is used for receiving the control instruction and operating according to the control instruction; the cabin wireless local area network system is connected with the Ka-band dual-mode broadband satellite communication airborne terminal and is used for providing internet service for passengers. The invention effectively meets the application requirements on domestic and foreign airlines, realizes a multi-mode working module, and has the advantages of high antenna profile, no beam handover function, strong Doppler adaptability, low design difficulty and strong market adaptability.

Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention or in the description of the prior art will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic module diagram of a Ka-band dual-mode airborne broadband satellite communication system according to an embodiment of the present invention;

fig. 2 is a schematic flow chart of beam switching in a Ka-band dual-mode airborne broadband satellite communication system according to another embodiment of the present invention;

fig. 3 is a schematic block diagram of a modem unit in a Ka-band dual-mode airborne broadband satellite communication system according to another embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.

As shown in fig. 1, the Ka-band dual-mode airborne broadband satellite communication system according to the embodiment of the present invention includes a display and control unit, a Ka-band dual-mode broadband satellite communication airborne terminal, and a cabin wireless local area network system.

The display control unit is connected with the Ka frequency band dual-mode broadband satellite communication airborne terminal and used for issuing a control command to the Ka frequency band dual-mode broadband satellite communication airborne terminal.

And the Ka-band dual-mode broadband satellite communication airborne terminal is used for receiving the control instruction and operating according to the control instruction.

The cabin wireless local area network system is connected with the Ka-band dual-mode broadband satellite communication airborne terminal and is used for providing internet service for passengers.

On the basis of the technical scheme, the invention can be further improved as follows.

Further, the Ka-band dual-mode broadband satellite communication airborne terminal comprises a Ka-variable polarization flat antenna unit and a modulation and demodulation unit;

the Ka-variant polarization panel antenna unit is used for providing wireless signal receiving and transmitting, servo tracking, power amplification, low-noise amplification, Ka up-conversion and Ka down-conversion.

The modulation and demodulation unit is used for receiving signals of the user terminal, processing control protocols and processing data.

Further, the cabin wireless local area network system comprises a network server, a wireless access device and a wireless communication device.

Further, the display and control unit is used for providing a man-machine interface, setting system reset, working mode switching and satellite fixed-point position parameters, and displaying a channel and a working state of the Ka-band dual-mode broadband satellite communication airborne terminal.

Furthermore, the Ka-variant polarization panel antenna unit comprises an antenna, an antenna control and management unit, a transceiving antenna unit, a Ka up-conversion unit and a Ka down-conversion unit.

Furthermore, the modulation and demodulation unit is provided with two comprehensive channel processing modules which are used for being respectively accessed to an I-5 satellite network and a China satellite-16 satellite network.

The working frequency band, the EIRP, the G/T, the polarization mode and the satellite tracking mode of the antenna are respectively matched with the I-5 satellite network and the middle satellite-16 satellite network.

Further, the modem unit is configured to receive a mode switching instruction issued by the display control unit, send the mode switching instruction to the antenna, activate a comprehensive channel processing module required by a current mode, and control the intermediate frequency switching module to switch a transmit-receive intermediate frequency signal of the antenna to a corresponding comprehensive channel processing module.

And the antenna is used for carrying out polarization and local oscillator switching and starting a satellite tracking process after receiving the called mode switching instruction.

And the modulation and demodulation unit is used for calling a special thread and a database resource to assist the antenna in beam switching and inhibiting adjacent satellite interference.

The integrated channel processing module is used for starting to receive a forward broadcast signaling issued by a satellite network management center after a wave beam of the antenna is aligned with a satellite, acquiring a working parameter of a current wave beam and sending a network access registration request to the network management center through a return network management channel, and sending a network access confirmation response to the Ka-band dual-mode broadband satellite communication airborne terminal through the forward broadcast channel after the network management center confirms, and the Ka-band dual-mode broadband satellite communication airborne terminal accesses the network after receiving the network access confirmation response.

Further, the beam switching includes switching between adjacent beams under the same satellite, switching between beams of different satellites under the same satellite network, and switching between beams of different satellite networks;

the switching between adjacent beams under the same satellite utilizes beam polarization multiplexing, the antenna re-tracks the satellite after switching the polarization mode, and the modulation and demodulation unit does not switch the comprehensive channel processing module any more.

And switching between different satellite beams in the same satellite network, restarting the acquisition and tracking satellite of the antenna according to the new satellite fixed-point position and the polarization parameter, and switching the comprehensive channel processing module by the modulation and demodulation unit.

And switching wave beams among different satellite networks, wherein the antenna retraces the satellite, and the modulation and demodulation unit switches the comprehensive channel processing module.

Further, the airborne EIRP of the Ka-band dual-mode broadband satellite communication airborne terminal conforms to the formula:

A_eirp≥E_th+10log(R_rm)-S_gt+L_r+M_r-228.6

wherein A is_eirpIs an airborne EIRP, E_thIs a demodulation threshold, R_rmTo return to the highest traffic rate, S_gtFor satellite transponder G/T value, M_rFor preparation of a balance of engineering, L_rLoss of a return machine-to-satellite link;

the airborne G/T value of the Ka-band dual-mode broadband satellite communication airborne terminal conforms to the formula:

A_gt≥E_th+10log(R_rm)-S_eirp+B_o+L_fw+M_r-228.6。

as shown in fig. 3, the modem unit includes an intermediate frequency switching module, an I-5 integrated channel processing module, a middle satellite-16 integrated channel processing module, a terminal monitoring module, an interface adaptation module, a beam switching module, an information storage module, an interface conversion module, and a power supply module.

It should be understood that the Ka-band dual-mode airborne broadband satellite communication system has the advantages that due to the fact that Ka-band spectrum resources are rich, the terminal aperture is smaller, the anti-interference capability is high, the Ka-band dual-mode airborne broadband satellite communication system is widely accepted in the global aviation satellite communication market, and by analyzing satellite resources and considering application requirements, beam coverage, reduction of the number of operators, simplification of equipment design and the like, Inmarsat five-generation satellite I5 and China's star-16 Ka-band high-throughput satellite are selected; a network structure based on the I-5 and the middle satellite 16 satellites is established, and according to satellite resources and application requirements, the airborne broadband satellite communication system can access the I-5 and the middle satellite 16 satellite networks in a time-sharing mode through a wireless link to realize dual-mode work; the main technical system is determined by analyzing the advantages of satellite resources and according to the characteristics of the application of the civil aviation airborne broadband.

In the interface part, although the sources of the gilt system adopted by the middle star 16 and the iDirect system adopted by the I5F4 are the same, interconnection and intercommunication still cannot be realized, and switching is realized through a dual-mode modem;

in the aspect of antenna form, because the panel antenna has advantages in the aspects of gain, scanning range, technical maturity, autonomous controllability, cost and the like, a satellite-alignment mode combining program guidance and cone scanning tracking is adopted, and a traditional dual-mode airborne panel antenna is used, wherein one side of the dual-mode airborne panel antenna is an antenna array surface matched with the middle satellite 16, the other side of the dual-mode airborne panel antenna is an antenna array surface matched with the I-5, and the dual-mode airborne panel antenna and the antenna array surface share one set of BUC and LNB, or a variable polarization panel airborne antenna is used.

The traditional dual-mode airborne flat antenna has the advantages that the technology is mature, engineering samples can be rapidly realized, and the advantages of airworthiness and evidence obtaining of the traditional airborne antenna can be fully utilized. The problem is that the cost, weight gain is large and a short network outage is likely to occur at the switching of the stars 16 and I-5.

The variable polarization airborne flat antenna has the advantages of low cost and weight amplification, little difference from the traditional single mode antenna, and capability of quickly realizing switching of a satellite network. The defects are that a certain development period is needed, and the verification of the product quality also needs time; in addition, due to the change of the antenna structure, the airworthiness evidence obtaining is influenced.

There are three beam switching techniques: switching between adjacent beams under the same satellite; switching between different satellite beams in the same satellite network; switching of beams between different satellite networks.

The first switching mode has high frequency, but each operator has a mature scheme, and the automatic switching can be realized in a coverage range; the switching between different satellite beams under the same satellite network mainly exists in an I-5 satellite network, and the automatic switching can be realized as well; and the switching of different satellite networks adopts a mode of manually switching by a network management center.

As shown in the beam switching process of fig. 2, the beam switching process is completed by the cooperation of the airborne terminal (including the antenna and the modem unit) and the ground network management center. For the first switching mode, the Ka frequency band high-flux satellite adopts a wave beam polarization multiplexing design, the antenna needs to switch the polarization mode and then tracks the satellite again, and the modulation and demodulation unit does not need to switch a comprehensive channel processing module; the second switching mode restarts the process of capturing and tracking the satellite by the antenna according to the new satellite fixed-point position and the polarization parameter, and the modulation and demodulation unit does not switch the comprehensive channel processing module; and in the process of re-tracking the satellite by the antenna in the third switching mode, the modulation and demodulation unit switches the comprehensive channel processing module. After the antenna and the modulation and demodulation unit are switched in place, the terminal applies for channel resources under a new beam to a network management center through a network management channel, service communication can be carried out after network access signaling interaction is completed under the new beam, and a beam switching process is completed.

Considering the airworthiness, the Ka-band airborne broadband satellite communication system refers to ARINIC 791-1-2014 in the aspects of electrical interconnection and functional characteristics, refers to ARINIC 791-2-2014 in the aspects of physical installation and airplane interfaces, refers to RTCA DO-254-2014 in hardware design, refers to RTCA DO-178B in software design and refers to RTCA DO-160G-2010 in environment adaptability according to the international standard.

The airborne equipment mainly comprises a Ka-band dual-mode broadband satellite communication airborne terminal (hereinafter referred to as a terminal), a display and control unit and a cabin wireless local area network, wherein the terminal provides a satellite-ground interconnection channel, the display and control unit provides a human-computer interface function, and the cabin wireless local area network provides cabin WiFi service.

The terminal comprises two parts, namely a Ka variable polarization panel antenna and a dual-mode modulation and demodulation unit. The Ka panel antenna has the functions of power amplification, low-noise amplification, Ka up/down conversion and the like besides the functions of wireless signal receiving and transmitting and servo tracking. From the generalization point of view, the antennas in the two modes of the middle star 16 and the I5 are consistent with the intermediate frequency of the modem unit. The modem unit is mainly responsible for processing signals, protocols and data of the terminal.

The wireless local area network system mainly comprises an onboard network server, a wireless access point and wireless communication equipment carried by passengers. The network server integrates the functions of an application server, large-capacity storage, network management, route switching and the like; the wireless access point is a bridge for passengers to access satellite Internet, and the passengers can access the Internet or access a cabin entertainment system in a Wi-Fi mode by using personal communication equipment by adopting an IEEE 802.11a/b/g/n standard mode.

The display control unit provides a man-machine interface for managing an airborne satellite communication terminal for a passenger cabin attendant, and sets parameters such as system reset, working mode switching, satellite fixed-point position and the like; the channel and equipment operating status are displayed, the cabin crew determines whether to notify passengers to begin using the satellite communication service based on the channel status, and resolves some simple faults based on the equipment operating status.

The dual-mode work is realized, the terminal has two working modes of I-5 and the middle satellite 16, the I-5 and the middle satellite-16 satellite networks are accessed in a time-sharing mode according to application requirements, and the working frequency band, the EIRP, the G/T, the polarization mode, the satellite tracking mode and the like of the antenna meet the requirements of the two satellite networks; the modulation and demodulation unit is adapted to the waveforms and protocols of the two satellite networks by arranging two comprehensive channel processing modules.

After receiving the mode switching instruction sent by the display control unit, the modem unit sends the mode switching instruction to the antenna through the monitoring and interface module, simultaneously activates the comprehensive channel processing module required by the current mode, and controls the intermediate frequency switching module to switch the receiving and transmitting intermediate frequency signal of the antenna to the corresponding comprehensive channel processing module.

After receiving the mode switching instruction, the antenna carries out polarization and local oscillator switching and starts a satellite tracking process, and the modulation and demodulation unit calls a special thread and a database resource to assist the antenna in carrying out beam switching and restraining adjacent satellite interference.

After the antenna wave beam is aligned with the satellite, the comprehensive channel processing module starts to receive a forward broadcast signaling sent by a satellite network management center, obtains the working parameters of the current wave beam and sends a network access registration request to the network management center through a backward network management channel, the network management center sends a network access confirmation response to the terminal through the forward broadcast channel after confirming, and the terminal indicates that the terminal is accessed to the network after receiving the network access confirmation response. The above process is repeated for the next mode switch.

In terms of service rate, as an air broadband infrastructure, a terminal supports as high a service rate as possible, but the service rate cannot be increased infinitely due to the limitation of antenna aperture and satellite capability. Considering a limit situation, namely all passengers on the airplane have the requirements of uploading and downloading at the same time, in order to avoid congestion, only one bandwidth which only meets basic user experience (such as webpage browsing, mail sending and receiving, and instant messaging tool using) can be allocated to each passenger at the moment, and the basic bandwidth can be set to be 256kbit/s at the downlink and 32kbit/s at the uplink, so that for a 160-class passenger plane, the highest forward traffic rate of the terminal is 40.96Mbit/s, and the highest backward traffic rate is 5.12 Mbit/s. In practice, the communication demand of each passenger is different, the traffic volume in different time periods is different, and the system reduces the occupation of satellite resources through adaptive rate control.

From the existing single mode terminal at present, Inmarsat single mode machine carries terminal can reach 50 Mbps's rate, can reach 120 Mbps's ability under the 16 terminal experimental conditions of well star, satisfies the demand that the machine carried broadband inserts.

In terms of the on-board EIRP and G/T indexes, because the EIRP and G/T of the gateway station are high enough, the link performance is mainly limited by the on-board EIRP and the satellite EIRP and G/T, and the on-board EIRP satisfies the following relation:

the airborne EIRP of the Ka-band dual-mode broadband satellite communication airborne terminal conforms to the formula:

A_eirp≥E_th+10log(R_rm)-S_gt+L_r+M_r-228.6

wherein A is_eirpIs an airborne EIRP, E_thIs a demodulation threshold, and generally takes 4.5dB, R_rmTo return to the highest traffic rate, S_gtFor satellite transponder G/T value, M_rMeasuring 3dB, L for spare amount of engineering_rFor the return machine-satellite link loss, Lr is 214.7 dB;

the airborne G/T value of the Ka-band dual-mode broadband satellite communication airborne terminal conforms to the formula:

A_gt≥E_th ⁺10log(Rrm)-S_eirp+B_o+L_fw+M_r-228.6。

the Ka-band dual-mode airborne broadband satellite communication system comprises a display control unit, a Ka-band dual-mode broadband satellite communication airborne terminal and a cabin wireless local area network system; the display control unit is connected with the Ka frequency band dual-mode broadband satellite communication airborne terminal and is used for issuing a control instruction to the Ka frequency band dual-mode broadband satellite communication airborne terminal; the Ka frequency band dual-mode broadband satellite communication airborne terminal is used for receiving the control instruction and operating according to the control instruction; the cabin wireless local area network system is connected with the Ka-band dual-mode broadband satellite communication airborne terminal and is used for providing internet service for passengers. The multi-mode working module has the advantages of high antenna profile, no beam handover function, strong Doppler adaptability, low design difficulty and strong market adaptability.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/terminal device and method may be implemented in other ways. For example, the above-described embodiments of the apparatus/terminal device are merely illustrative, and for example, the division of the modules or units is only one logical division, and there may be other divisions when actually implemented, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated modules/units, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer readable storage medium.

Based on such understanding, all or part of the flow of the method according to the embodiments of the present invention may also be implemented by a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method embodiments may be implemented. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain other components which may be suitably increased or decreased as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media which may not include electrical carrier signals and telecommunications signals in accordance with legislation and patent practice.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.

While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.