Study On The DVB-T Algorithm And FPGA Implementation For UAV Image Transmission

With the rapid development of UAV(Unmanned Aerial Vehicle)and related technologies,its applications become more and more extensive.At present,UAVs have been applied in many fields,such as pesticides spraying,electric power detection,geology exploration,disaster emergency response,mapping and environmental monitoring.Most of these scenarios involve wireless image transmission modules.Traditional wireless image transmission is mainly analog,which has limitation in stability,transmission distance and picture quality.Nowadays,digital image transmission has become the main development trend,but at present,digital image transmission based on CPU or DSP still faces many problems,such as high cost,high power consumption and low reliability.Therefore,there is still great room for the optimization and development of UAV digital wireless image transmission.In view of the above background,this paper proposes a new solution of wireless digital image transmission of UAV.The channel coding and modulation part is studied and improved emphatically.This paper takes European standard DVB-T as the main reference to carry out directional improvement and optimization for the specific application scenario of UAV image transmission.In the convolutional interleaving part,the depth of interleaving is increased,and a choice of tradeoff is made between the interleaving depth and the implementation complexity and the delay time,so that it has stronger anti-interference ability in the mobile environment.In the OFDM module,a scheme with fixed pseudo-random sequences as prefixes for guard intervals is provided.This can greatly reduce the synchronization time of the receiving end and improve the real-time of wireless transmission.The optimized design is compatible with the existing DVB-T receiving chip and can recognize all modes through the self-developed demodulation chip to achieve the best performance.In this paper,MATLAB is used to complete the simulation of the modules.The circuit design of all modules is completed,and the circuit design of several schemes is carried out for some of the modules.By comparison and analysis,it can consume less FPGA resources as much as possible.Finally,the Spartan 6 series FPGA chip was used to build the hardware system,and a complete verification scheme was designed.The correctness of its function is verified on the wireless graph transmission system which is composed of chip such as video compression,channel coding and modulation and DAC.The physical design of digital wireless image transmission of UAV with low power consumption,low cost,high bit rate and strong anti-interference ability has been completed.Moreover,FPGA is adopted to meet the strict requirements for the size and area of the image transmission system of micro UAV.