无人机载图像实时传输方案的研究

根据无人机载图像实时传输系统的要求,提出了一套采用基于整数小波变换(IWT)和改进SPIHT(Set Partitioning In Hierarchical Trees)的图像压缩编码、级联格状编码和正交频分复用调制(OFDM)的系统方案.该系统方案信源编码压缩率连续可调、累进传输、运算效率高且有抗差错能力,信道频谱利用率高且不会因为介入噪声或干扰而使性能受损,同时OFDM技术使得系统具有抗多径、抗回波性.因此该系统方案适合无人机工作环境,是一种可行的系统方案.

A Real-Time Image Transmission Scheme for Pilotless Aircraft

In the present scheme, an integer wavelet transform algorithm with modified set partitioning in hierarchical trees(SPIHT) coder was introduced to compress images. RS, symbol interleaves and trellis coded modulation(TCM) with multi level quadrature amplitude modulation(QAM) were used to get an excellent forward error correcting ability. Orthogonal frequency division multiplexing(OFDM) scheme was adopted to improve spectrum efficiency and to decrease the average power. Bit error probability of the scheme was analyzed. The scheme was shown to possess higher compression rate, stronger progressive transmission ability, better numeration efficiency and more excellent error resilience. Together with a performance of multi path resilience and echo resilience, the above advantages make the proposed scheme compliant with pilotless aircraft conditions and feasible in practice.