For the characteristics of simulation training of air navigation radar, a new control version which is close to the real machine and can be used for radar simulation controller is designed, and it can be used for common radar training. The control board is easy to carry and simple to use. This control board combines keys, potentiometers, USB serial ports and other circuits with a single chip computer to program all kinds of analog signals and realize the direct control of computer simulation software. The control board can reset the functions of keys and potentiometers according to different radar signals, and all kinds of compiler software can be downloaded through serial ports. In radar training, because the location of radar is often affected by the surrounding environment, the echo is quite different from the real situation, which results in the phenomenon of weak training pertinence, electromagnetic wave affecting health, waste of resources and so on. Radar simulator realizes real radar echo without electromagnetic wave. The trainer uses mouse to control radar, but it is not practical in practice because of the big gap between radar simulator and real radar. Semi-real simulation training is a training method that matches the real radar display and the generator of the transceiver.
This training method reduces the electromagnetic radiation, but the signal generator can only store fewer types of echoes. Based on the above problems, a new radar training method is proposed, which uses real radar operation panel control software radar simulator to complete radar training. Software simulator technology is relatively mature at this stage, as long as the appropriate interface can be used to achieve. The control board of the radar simulator designed in this paper takes the single chip computer as the core and combines A/D sampling, then converts the potentiometer and key into code, and realizes interaction with the computer through serial port.
Therefore, the core of hardware and software designers in the control board design. This controller can realize the convenient operation training of various types of radar approaching the real machine. The control block diagram of the radar simulator is shown in Fig.
1. The potentiometer circuit can realize the circuit in various environments. The continuous analog voltage signal generated by the potentiometer must be converted into digital signal after A/D sampling. The single chip computer sends digital signal to the computer to realize the control of the simulator. The key circuit is the switch of various functions of the radar and works at a high level. Low level, through the design of the circuit with the door to interrupt the key scanning work. The power supply provides power for all kinds of electrical appliances, and the crystal oscillator of the oscillator provides the clock for the MCU and the interface chip. Radar control panel control keys generally have about 20 keys, potentiometers have about 5, so in the selection of single-chip computer is to consider whether the foot tube is enough, but also to consider whether the sampler is self-contained and cost-effective is appropriate, the author chose the STC12C5A60S2 control chip produced by Hongjing Company, which has low power consumption, high speed. 8051 MCU with strong anti-jamming ability can be compatible with 8051 in instruction code, which is 11 times faster than the previous generation and can bring 10 bit A/D conversion.
MCU design focuses on the selection of external crystal frequency. We set the initial value of the timer as an integer, which is conducive to the accurate transmission of baud rate gold by USB serial port. The selected value is 11.0592 MHz. It is necessary to set a switch on the power supply because STC12C5A60S2 can only download the program of the single chip computer when the power is off. The reset key must also be set to suit the reset control of single chip computer.
USB serial port is a kind of universal serial port, which is used for data transmission of PC in external devices and hot plug-in function of Jiyou. We use TXD and RXD serial communication pins of STC12C5A60S2 to realize serial USB circuit through CH340 chip. This machine uses the PL2303HX conversion chip developed by Prolific to realize the serial USB circuit. PL2303HX can realize the data communication with the computer by resistor and capacitor. The serial communication pins between TXD and RXD of PL2303HX should be connected with single chip microcomputer P3.0 and P3.
1 to make differential processing links. The 12MHz crystal oscillator is PL2303HX to raise the clock, and the peripheral capacitor is used to oscillate the capacitor. We link a 27_terminal matching resistance at D-and D ports respectively to prevent the reflection of signals at the ports. To realize the enumeration function, 1.5k pull-up resistance can be added to the D terminal. The control board is powered by USB interface. It needs to use C and C15 capacitors at the output of power supply to process power filter. The function of key circuit is to control the software of computer simulator to perform the corresponding function after the practitioner presses the key. For example, when we press the power switch key, the simulator starts to work after buzzing. We output a low level after the key to the MCU, thermostatic element and send it to the computer after the big year and the scan confirms that it is the switch key. Binary code. Therefore, we use the simplest circuit in hardware design.
When the S1 key is not pressed, the switch key is connected to the power supply through pull-up resistance, and the switching voltage is high. When the S1 is pressed, the 1 and 4 ends of the S1 are connected, the switching end is grounded, the output level is low.
When the S1 is loosened, the 1 and 4 ends are disconnected, and the switch is restored to the high level before. Potentiometer circuit is a button control circuit. When we control the knob, we will produce a continuous analog voltage signal to control the radar function. The single chip computer we use can not recognize this continuous signal, so we need to sample and control the voltage signal, considering the cost of control, we use the sampler with the single chip computer. Sampling and sending the changed voltage to the P0 port of MCU can be done. There are dozens of interface changes in the simulation software we designed, so we need to calculate the magnitude of the analog voltage of P0 port. We keep the voltage sent to P 0 between 0 and 2V to meet the need of simulation software upgrade. The analog signal can be converted into binary code by MCU and then docked with PC to realize the control of analog software. Because of the use of USB serial port, it has the characteristics of flexible use and strong authenticity.
According to the operation interface of air early warning radar, a radar control board based on STC12C5A60S2 single chip computer is designed, and the hardware design of circuit, USB serial port, button, potentiometer and so on is briefly introduced.