Selection of Beidou equipment

If a worker wants to do a good job, he must sharpen his tools first. The selection of Beidou equipment is the first step of Beidou technology application. If we want to select products suitable for geological work from many brands and models of Beidou equipment, we need to have a detailed understanding of its characteristics and usage.

According to the function of the equipment, Beidou equipment can be divided into two categories: commander and mobile terminal.

First, the Beidou command machine

Beidou commander refers to Beidou equipment with monitoring and command functions, which can monitor and command a certain number of subordinate terminals and is generally deployed at fixed nodes with management functions. According to the differences in the number and configuration of subordinate users, it can generally be divided into central commanders and ordinary commanders.

(1) Beidou central command user machine

The main function of Beidou central command user machine is to monitor and manage the users under its jurisdiction. The central commander can manage 1000 subordinate users. Beidou commander not only has the functions of positioning, communication, navigation and timing, but also has the functions of command, scheduling, monitoring and broadcasting. Adapt to the use of relatively fixed command nodes. The central commander has his own display screen and operating system, which can be used as an ordinary server.

Figure 6- 1 Beidou Central Command User Machine

(1) Commander configuration and deployment

Beidou central command user machine is mainly composed of host, antenna, cable and accessories. As shown in figure 6- 1 and figure 6-2.

When deploying equipment, pay attention to placing the antenna at the top of the building and keep the antenna open to the air in the south to receive Beidou signals.

Figure 6-2 Deployment Diagram of Beidou-1 Central Command User Machine

(2) Performance indicators

1) reception index: the bit error rate of the received signal is ≤ 1× 10-5 (the input signal power of the user antenna port is ≥-157.6 dbw);

2) Emission index: EIRP value of emission power ≤ 19dBW (azimuth angle 0 ~ 360, elevation angle10 ~ 75);

3) Number of satellite channels received: 6 channels;

4) Zero value of equipment: 1ms 10ns.

(3) Functional indicators

1) positioning function: positioning accuracy: 20m( 1σ) (mark calibration station area); 100m( 1σ) (area without standard calibration station);

2) SMS communication function;

3) Navigation function;

4) Command function: The number of users under the acquisition command can be monitored at the same time ≤ 1000.

(2) Beidou General Command User Machine

The main functional difference between Beidou general command user machine and central command machine is that the number of monitored terminals is different. Ordinary commanders can monitor at most 100 subordinate users. It has the functions of positioning, communication, navigation, time service, command, scheduling, monitoring and broadcasting. Ordinary commanders don't have their own servers, so they need to be connected to other PCs or servers. Therefore, the cost of the whole machine is lower than that of the centralized commander (Figure 6-3 and Figure 6-4).

Figure 6-3 User Machine Deployment Diagram of Beidou No.1 General Command

(1) product function

1) adopts the patented technology of "first-line communication", that is, the bidirectional transmission of Beidou transceiver signals and power signals is realized through a radio frequency coaxial cable. So as to facilitate the connection between the antenna and the host computer and make the use of users more convenient and reliable.

2) Support RS232 interface.

(2) Performance indicators

1) reception index: the bit error rate of the received signal is ≤l× 10-5 (the input signal power of the user antenna port is ≥-≥-157.6 dbw);

2) Emission index: EIRP value of emission power ≤ 19dBW (azimuth angle 0 ~ 360. Elevation10 ~ 75);

3) Number of satellite channels received: 6 channels;

4) Zero value of equipment: 1ms 10ns.

(3) Functional indicators

1) positioning function: positioning accuracy: 20m( 1σ) (mark calibration station area); 100m( 1σ) (area without standard calibration station);

2) SMS communication function;

3) Dynamic networking function: flexible dynamic networking can be carried out according to user requirements, so as to monitor the information of lower users.

Figure 6.4 Beidou General Command User Machine

(3) Selection and configuration of Beidou commander.

Beidou commander can make the command node control the dynamic situation of subordinate terminals in real time, and conduct command monitoring, security guarantee and information service push. The specific choice of central or ordinary command aircraft should be comprehensively considered according to the scale of command nodes and the cost of funds. For the fixed nodes at the level of geological prospecting bureau or geological prospecting center, because there are many subordinate users, we can consider choosing a central command or even multiple parallel connections; For provincial geological survey institutes or field stagnation nodes, because of their small scale, some of them need to be disassembled and moved frequently, so it is more appropriate to choose ordinary command machines.

When assembling the Beidou commander, attention should be paid to fixing the antenna in the open south to ensure the smooth reception of Beidou signals.

Second, Beidou mobile terminal

Beidou mobile terminal is used to move a single node, including personnel, vehicles and large equipment. With the maturity of Beidou technology, the emergence of Beidou second-generation chip-level products has further promoted the diversification and miniaturization of Beidou terminals. According to the different ways of using the terminal, it can be divided into vehicle-mounted machine, hand-held integrated terminal and Bluetooth split terminal. How to choose the Beidou terminal suitable for field work is the key to the popularization and application of Beidou technology.

(1) Beidou vehicle-mounted user machine

Beidou vehicle-mounted user machines can be divided into embedded Beidou vehicle-mounted user machines and separated Beidou vehicle-mounted user machines according to the assembly mode. The embedded Beidou on-board user machine dives the display and control terminal into the control panel of the car body, generally using a touch screen. Users can control Beidou related functions through the touch screen, and the equipment will automatically start with the start of the vehicle. The display terminal of the separated Beidou vehicle-mounted user machine is not associated with the vehicle body at first, and the user controls the Beidou function by operating the handle. Generally, the display screen is relatively small, and the vehicle needs to supply power to the handle and antenna through the on-board power supply. Every time you start the vehicle, you need to manually restart the handle control end.

Beidou vehicle-mounted user machine can be installed on various vehicles for use. It not only has Beidou positioning, communication, navigation and timing functions, but also has GPS navigation and positioning functions, receives differential information broadcast by China Satellite Navigation Enhancement System, realizes differential GPS navigation and positioning and other working modes, and can provide users with functions such as manually setting working modes and editing switching strategies of working modes.

Beidou vehicle-mounted user machine is mainly composed of an all-in-one machine, cables, lithium batteries, operating handles and accessories (Figure 6-5).

(2) Beidou handheld integrated terminal

Beidou handheld user machine combines Beidou navigation communication with GPS, with its own display screen and operating system, which is easy to carry and operate, and can realize Beidou positioning, communication and navigation functions, and is suitable for individual soldiers in the field.

Beidou equipment manufacturers design different types of terminals according to different user needs and occasions. In terms of operating system, there are both traditional W indows CE and popular Android system: in terms of appearance design, there are both industrial-grade three-proof design suitable for the wild and light design suitable for business; In the way of use, there are both high-integration integrated design and detachable split design. Here are some common Beidou handheld terminals.

(1) Beidou-1 /GPS dual-mode handheld user machine

"Beidou-1" handheld user machine is a user terminal of Beidou-1 system. Combining the functions of Beidou-1 and /GPS, and adopting Windows CE operating system, it can meet the positioning communication needs of individual handheld users. The antenna, RF unit and signal processing motherboard are integrated into one unit. The host computer includes a display touch screen, a keyboard, an external data interface and a power interface (Figure 6-6). The user's computer is powered by battery, information input is completed by stylus or keyboard, and various applications of the user's computer are completed by human-computer interaction software installed on the handset. Dual-mode user machine has Beidou positioning and GPS positioning and navigation, and receives differential information broadcast by China Satellite Navigation Enhancement System to realize differential GPS navigation and positioning.

Figure 6-5 Beidou vehicle-mounted dual-mode user machine

Figure 6-6 "Beidou-1" Handheld Integrated Terminal

(2) Three-proof Beidou second-generation mobile phone

The machine adopts industrial-grade three-proof design, integrates Beidou second-generation navigation and communication, GPS, Bluetooth, W ifi, 3G and other technologies, and is equipped with Android 4.0 operating system, with high integration and good expansibility (Figure 6-7).

Figure 6-7 Three-proof Beidou Second Generation Mobile Phone

(3) Detachable Beidou II mobile phone

The machine adopts flexible and detachable design, and the base can be used for Beidou to send Beidou short messages. The host computer is equivalent to a mobile phone, which has the functions of Beidou second-generation positioning, GPS and 3G communication. Usually, in the case of mobile phone network coverage, the host can be used alone, but when entering the field environment without network, the base can be temporarily assembled to realize Beidou communication (Figure 6-8).

Figure 6-8 Detachable Beidou Second Generation Mobile Phone

(3) Beidou Bluetooth Split Terminal

Beidou Bluetooth split terminal is an independent Beidou data access module, which can be used with various display and control terminals through Bluetooth function. It is flexible, convenient and easy to use. Because the equipment is small and portable, it can be used with the existing digital geological survey field data acquisition equipment (Figure 6-9).

Figure 6-9 Beidou Bluetooth split terminal and display and control terminal are used together.

In addition to the basic functions of Beidou positioning and communication, the terminal also has the following characteristics:

1) The combination of "Beidou-1" positioning communication and G PS: Beidou and GPS dual-mode fusion technology can be used for Beidou satellite and GPS positioning. In the absence of a display terminal, positioning information can also be automatically sent back to commanders at different levels according to frequency.

2) SMS caching function: When the terminal is turned on and not connected to the PDA, the received SMS (up to 20 messages) will be stored in the internal cache, and then the cached SMS will be "spit out" together when the PDA is connected.

3) One-click "safety report" and distress alarm function: two shortcut buttons of "safety" and "danger" are provided, and users can set the sending address and short message content of the two shortcut buttons through software to realize one-click safety report or distress alarm function.

4) One-button off-line SMS query: provide a shortcut button for off-line SMS query (that is, when the terminal is turned off or the signal is bad). When the terminal is turned off or the signal is not good, when there is a signal, you can query all offline messages at the satellite main station to ensure that the messages are not leaked.

(D) Beidou mobile terminal selection

Different Beidou devices have positioning and communication functions in basic functions, but different devices have different application modes and suitable user groups. Users should be equipped with suitable Beidou mobile devices for field use according to their own needs.

The selection of Beidou vehicle-mounted user machine should be considered comprehensively according to the workload of vehicle modification and user demand, because the embedded vehicle-mounted Beidou terminal is convenient to operate, but it needs to modify the car body, which requires high technical requirements for assembly and relatively difficult for later maintenance. Therefore, it is suitable for the configuration selection of newly purchased vehicles. Before the vehicle leaves the factory, the vehicle-mounted Beidou terminal is embedded in the operation panel of the vehicle through consultation with the vehicle manufacturer, which is not only beautiful and convenient to operate, but also relatively fixed and not easy to be damaged. Compared with the embedded vehicle-mounted Beidou user machine, the separated vehicle-mounted Beidou terminal has lower assembly technical requirements, less changes to the vehicle, convenient disassembly and lower technical requirements for later maintenance, and is more suitable for the assembly of existing vehicles.

For the selection of user terminal, it is necessary to analyze the user's existing equipment, the user's application purpose and the advantages and disadvantages of the equipment, so as to determine the appropriate terminal equipment. For the field engineering that has already carried out digital mapping, because it has been equipped with certain equipment such as PDA, the requirements of Beidou communication, positioning service and field digital geological survey can be met only by configuring Beidou Bluetooth split terminal, and the cost can be effectively controlled. For the project team that has not carried out digital mapping or does not need to collect field data, when Beidou equipment is only used for communication and security, it should be equipped with Beidou handheld integrated terminal. Due to the Bluetooth connection of Beidou Bluetooth split terminal, real-time information cannot be guaranteed when Bluetooth is disconnected for some reason, which has certain security risks. With the development of geological survey system based on Android system, users can also choose the detachable Beidou second-generation handset based on Android system when purchasing new digital geological survey equipment terminals. When users conduct digital geological survey, they can disassemble the terminal and operate together with users. When users need it as a secure terminal, they can integrate applications and avoid the instability of Bluetooth transmission.