Research On Drive Control System Of Liquid Crystal Light Valve Based On FPGA

Star sensor is the core component of measuring satellite attitude in aerospace field,and dynamic star simulator is the ground-based performance testing equipment of star sensor.In the dynamic star simulator,the star map simulation is realized by using the liquid crystal light valve to provide star map navigation for the star sensor,which is widely used in the functional verification of the star sensor.In researching high-resolution,real-time,and high-speed star map display system,it is necessary to ensure the refresh rate of star maps at high resolution.In this paper,FPGA is used as the main controller to design a set of liquid crystal light valve drive control system.Using DVI interface and video decoding technology,DDR2 SDRAM cache ping-pong operation technology and parallel D/A conversion technology,the problem of mismatch between star map data and output signal timing is solved,and the real-time display of star map with high refresh rate is effectively guaranteed.At the same time,the hardware circuit and software algorithm of FPGA are designed by using overdrive technology to improve the motion artifacts caused by high refresh rate of dynamic star simulator.The system can realize the star map display of liquid crystal light valve with resolution of 2048*1556 and refresh rate of 60 Hz,which provides technical support for the development of star map display equipment of dynamic star simulator with high resolution and high refresh rate.In this paper,FPGA is used as the main controller,through the DVI interface and video decoding module,the star image generated by the computer is processed by video decoding.The decoded video signal is cached and processed by ping-pong operation to solve the problem of real-time transmission of video signals across the clock domains.Design the control timing of the parallel D/A conversion chips and the control timing of the liquid crystal light valve inside the FPGA to effectively display the cached video signal on the liquid crystal light valve.At the same time,ARM is used as the co-controller to complete the configuration of the chip,control backlight,EDID communication and other functions in the star map display drive control system.Due to the motion artifacts of the liquid crystal display device at high refresh rate,there will be dragging shadows on the star position when refreshing the display of the star map.In this paper,an FPGA overdrive module that can seamlessly access the star map display system is designed and developed by using overdrive technology to improve the star map dragging phenomenon caused by high refresh rate.Finally,this paper builds a liquid crystal light valve drive experimental platform to verify the refresh time of star map display in the system,and to verify the effect of star map display before and after the introduction of the overdrive module.The verification results indicate that the liquid crystal light valve drive control system designed in this paper meets the design requirements with the resolution of 2048*1556 and no obvious dragging shadow,and the dynamic star simulator star map refresh time is less than 50 ms.