高动态短猝发扩频自适应信号快捕系统设计

Design of High Dynamic Short Burst Spread Spectrum Adaptive Signal Fast Capture System

摘要:

在高动态环境下,短猝发信号传输过程中往往会产生普勒频偏,增加扩频信号的捕获时间,甚至降低信号捕获信噪比,为实现对扩频自适应信号的快速、有效捕获,设计高动态短猝发扩频自适应信号快捕系统。系统硬件采用模块化设计方式,改装信号接收模块和滤波模块,从信号缓存和锁相环两个方面调整系统电路。在硬件系统支持下,通过扩频过程的模拟确定高动态短猝发扩频信号特征,通过特征匹配实现对高动态环境中短猝发扩频信号的自适应搜索。计算捕获长度、频率、门限等参数,实现系统的短猝发扩频自适应信号快速捕获功能。实验结果表明,在无噪声条件下,优化设计系统输出扩频信号信噪比的平均值为141.6,捕获时间平均为8s,捕获面积平均为90km2；在有噪声条件下,系统输出扩频信号信噪比的平均值为121.8,捕获时间为10s,捕获面积为130km2。

Abstract:

In high dynamic environments, the transmission process of short burst signals often produces Puller frequency offset, increasing the acquisition time of spread spectrum signals, and even reducing the signal-to-noise ratio of signal acquisition. In order to achieve fast and effective acquisition of spread spectrum adaptive signals, a high dynamic short burst spread spectrum adaptive signal fast acquisition system is designed. The system hardware adopts a modular design approach, modifying the signal receiving module and filtering module, and adjusting the system circuit from two aspects: signal buffering and phase-locked loop. Supported by the hardware system, the characteristics of high dynamic short burst spread spectrum signals are determined through simulation of the spread spectrum process, and adaptive search for short burst spread spectrum signals in high dynamic environments is achieved through feature matching. Calculate the capture length, frequency, threshold and other parameters to achieve the system"s fast capture function of short burst spread spectrum adaptive signals. The experimental results show that under the condition of no noise, the average signal-to-noise ratio of the optimized design system"s output spread spectrum signal is 141.6, the average capture time is 8 seconds, and the average capture area is 90 km2; Under noisy conditions, the average signal-to-noise ratio of the system"s output spread spectrum signal is 121.8, the capture time is 10 seconds, and the capture area is 130km2.