音码混合测距在深空探测中的应用研究

Application of Tone-code Ranging in Deep Space Exploration

深空探测具有目标距离远、信号往返时延大和信号微弱等特点,纯侧音测距和伪码测距无法满足深空测距的需求;提出了一种适用于深空探测的音码混合测距方法,详细分析了测距信号发送、接收时序,对由于超远距离、超大时延引起的测距信号返回时间预报偏差较大,采取有效的保护措施,减小测距信号返回时间预报偏差,避免距离匹配出错;阐述了距离捕获、解模糊和跟踪的过程,充分考虑了音码相位进周问题,提出了改进措施,提高了距离测量值的准确性;分析估算了测距精度和距离捕获时间,分析结果表明文章提出的音码混合测距方案具有较高的测距精度,较短的距离捕获时间;最后在由DSP和FPGA构建的全数字化控制平台上进行了实验研究,与纯侧音测距相比,音码混合测距精度更高,测距值更稳定。

The deep space exploration has extremely long-range,large delay of signal round trip,weak signal and other characteristics,pure tone ranging and PN ranging are unable to meet the demand of deep space ranging.A method of tone-code ranging that is suitable to the deep space exploration was proposed,and the transmitting and reception timing of the ranging signal was analyzed in detail.Because of the large forecast deviation of ranging signal return time caused by long-range and large delay,some effective protective measures were taken to reduce the forecast deviations of the ranging signal return time and avoid the match mistakes.The process of ranging capture and tracking were elaborated,in which the phase cycle of tone-code considered fully,and the improvement measures were proposed to improve the accuracy of range measurement.The ranging accuracy and capture time were analyzed;the results show that the tone-code Ranging proposed in paper is with higher accuracy and shorter capture time：Finally,the experiment was carried out on fully Digitized Control platform constructed by DSP and FPGA,compared with pure tone ranging,the accuracy of tone-code was higher,and range value is more stable.