Communication mode on emergency lifting communication command vehicle

Time：2020-08-06 View：

In order to ensure the emergency Emergency Events, the emergency communication command vehicle designed by our company can complete various communication command tasks under various harsh conditions. The communication command vehicle adopts advanced vehicle modification technology, satellite communication technology, image acquisition and transmission technology, computer communication technology, wireless microwave transmission and image processing technology, etc. form a mobile command center with relatively complete functions, the system is flexible in handling emergency Emergency Events, fast response, realize communication guarantee, command and dispatch, image acquisition and transmission functions, pass the scene situation back to the command center through the vehicle-mounted satellite system with high quality, realize remote image monitoring between the site and the remote command center, voice contact and data query enable the command and decision-making personnel of the command center to get on-site information in a timely manner and improve the accuracy and timeliness of decision-making. To provide reliable communication guarantee for the linkage between the event site and the remote command center.
The communication command vehicle is equipped with various modes such as satellite communication, ground wireless communication and so on. All communication modes complement and back up each other to ensure that communication is not interrupted under any circumstances, provide reliable guarantee for the successful completion of various tasks.

 

The communication system of the communication command vehicle requires the following functions:
· It has satellite communication capability and can provide bidirectional video, audio and data transmission capability of not less than 2048kbps. The video signal adopts MPEG-4 compression format.
· It has GSM mobile phone, maritime satellite phone and GPRS/CDMA wireless communication terminal.
· It has multiple fixed camera image inputs and one wireless microwave image input.
· Have the ability to switch audio and video and process.
· It has multi-channel video and audio hard disk recording capability.
· Have the ability to surf the Internet through the Internet through computers.
· It has an electronic display system outside the car, and can update and modify the display content at any time in the car.

The integrated design of satellite communication system fully considers the technical system and equipment performance of the existing satellite communication system, and pays attention to its adaptability and compatibility. With the development of technology and the new requirements of users, the system and structure are scalable, including hardware compatibility and software upgrade and expansion.
As a supplement to ground communication, satellite communication is not limited by region, has wide coverage, long communication distance, convenient site setting, good signal transmission quality, and can be point-to-point, point-to-point image, voice, data transmission, convenient access to the ground communication network and many other advantages. The site location of the Emergency Events is random, while the coverage of ground wired and wireless communication lines is limited, the transmission rate bandwidth is limited, and the transmission quality is low. When performing the task, the communication command vehicle can arrive at the scene at the first time, and can establish an emergency command communication link for the scene and the remote command center in the shortest time. The mobile satellite vehicle station can be used to open the satellite communication link conveniently and quickly, and solve the communication problem of on-site images, voice and data.
The satellite communication system consists of vehicle-mounted satellite stations, communication satellites and satellite ground stations. After the communication command vehicle arrives at the scene, the vehicle-mounted satellite communication sub-system can quickly enter the working state after power-on. The antenna automatic servo and control system can be used to accurately align the antenna with the designated satellite within a few minutes, and the satellite channel can be opened in time, give full play to the advantages of fast and effective establishment of satellite channels, low bit error rate, wide coverage and so on, and realize the transmission of images, voice and data between command vehicles and command centers.
The communication between the command vehicle and the remote command center is connected through the satellite link to realize the bidirectional or unidirectional transmission of images, voice and data.

Satellite image transmission adopts MPEG-4 coding, and the image quality received by the ground station can reach the DVD quality.
According to the characteristics of the emergency communication command vehicle and the needs of actual work, the satellite communication system of the communication command vehicle adopts asymmetric and reusable single carrier transmission mode. This transmission mode determines the realization of point-to-point image, data and voice transmission between the communication command vehicle and the command center. Since satellite transmission belongs to broadcasting mode, when the communication command vehicle and the command center conduct point-to-point communication, other stations (equipped with the same multiplexer and decoder) can also receive signals from the communication command vehicle.
The selected multiplexer can realize asymmetric communication when images, data and voice are connected simultaneously from station to station. Because the multiplexer uses TDM technology, you can reserve a specified bandwidth for each data interface. Because the codec transmits real-time images, the multiplexer needs to reserve sufficient bandwidth for it to ensure the image quality, and reserve a specified bandwidth for voice and data to ensure low information delay, data, the signal delay such as voice is fixed.
The selected image transmission can realize the real-time transmission of one-way and two-way images between the site and the ground station of the command center, and the image transmission bandwidth is 1~4 megabytes. The analog video and audio signals collected on site in real time are sent to the encoder through the video and audio matrix, and compressed and encoded according to the MPEG-4 standard. The encoded code stream is input to the multiplexer, voice and data reuse through the data interface. After modulation, frequency conversion and power amplification, it is sent back to the remote command center by using the designated transponder, provide the leaders with information about the scene.
The ground station of the command center can also use the same method to return the image to the communication command vehicle.
Through link calculation and reasonable equipment selection, the satellite transmission system can ensure that the transmitted images are clear, without mosaic, broken code, broken frame and other phenomena, and the sound is clear to achieve DVD quality.
Data transmission adopts IPC and notebook equipped in the car, and uses satellite channel or ground GSM/CDMA wireless network to access the command center network to query all kinds of information and transfer files, achieve Data exchange with the command center.
The satellite system consists of uplink and downlink.
The satellite uplink workflow is that after the collected video and audio signals are input into the audio and video matrix, the staff will choose to output one audio and video signal according to their needs. The signal is compressed and encoded by the encoder to output the data stream. This data stream is connected to the multiplexer.
The multiplexer has a voice interface, which can connect up to one phone, fax machine or telephone switch. The multiplexer has an IP network interface, which is used to connect to the Ethernet switch with a network cable. The multiplexer itself supports multiple Ethernet communication protocols, and all computer data connected to the Ethernet switch can be transmitted to the multiplexer through the Ethernet switch. The internal high-speed data processing board is used to statistically reuse the received encoded images, voice and computer data.
The reused data is output to the data modulator, and the modulator outputs intermediate frequency signals after error correction and modulation. The frequency conversion is carried out by the upconverter, and the output radio frequency signals are amplified by the high-power amplifier, send to satellite via antenna.
The working process of satellite downlink is that the vehicle antenna outputs L-band signals after receiving the satellite downlink signals through amplification and frequency conversion. The signals output by the amplifier are divided into equal channels through the power divider, and each signal can be sent to different equipment to realize different functions.
If the demodulator of the communication command vehicle does not receive the carrier back from the ground station of the demodulator command center, it can also demodulate the spontaneous carrier transmitted by the communication vehicle through the satellite to decode the image and monitor the quality of the spontaneous image, it is an inspection method for the command vehicle to check whether the satellite link works normally, which is conducive to the elimination of satellite system faults.