Uav Data Link Key Technologies

In modern electronic warfare environment, the data link system for unmanned aerial vehicle (UAV) need transmit very large capability and face the superpower and broad spectrum electromagnetic environment generated by hundreds of communication broadcasting stations and radar and has the selected electronic interference signal. So the anti-interference technique is the key technology to ensure the communication link quickly, accurately, securely, straightway and the main research problem need to solve. The modulation types of data link for UAV are simple, such as BPSK, 2FSK , direct spread spectrum. The transmitted rate and anti-interference performance of them are limited. Based on the existing condition of data link for UAV, this paper is introduced the advanced coded modulation scheme and digital down cinversion (DDC) based on software radio (SWR) in the data link system for UAV. And the two key techniques are analyzed and simulated. The design of filter which is decided by specifical instance is the difficulty and key in the DDC. The simulations show that: using decimation and filter can effectively separate and demodulate the single and multipath signal, the adaptable DDC based on SWR has the more flexibility and adaptability than the DDC chip, and can be effectively applied in the digital receiver; the asymmetric trellis coded modulation scheme, which is presented in the paper and can be well applied in wireless fading channel, improves the performance of error correction and anti-multipath interference in the system, and can be effectively used in the strong mutipath interference channal. Finally the system is proved throught the microwave instruments and SWR, and the author make a customer used interface whose name is the demodulation system based on software radio. The paper provides a certain theory foundation and reference value for UAV's data link of superwide band and more anti-interference, and makes reducing the flight risk and testing cost, and shortening the development cycle of the UAV possible.