基于混沌振子的微弱GPS信号检测算法

Weak GPS Signal Acquisition Algorithm Based on Chaos Oscillator

针对微弱GPS信号的高灵敏度检测算法是当前室内环境下,GPS接收机捕获信号亟待解决的问题。由于混沌振子具有对周期信号敏感,对噪声免疫的特性,相轨迹会因为同频率周期信号发生明显改变。本文将其应用于室内环境下检测GPS信号,提出了基于Duffing混沌振子的微弱GPS信号检测算法;采用Leyapunov指数判定相轨迹所处的临界状态,辅助测量GPS信号的存在;将数值迭代方法应用于算法的实现。仿真结果表明,与传统的GPS信号检测方法相比较,基于混沌振子的检测算法可以快速捕获极低信噪比条件下的GPS信号,有效提高了捕获率和检测性能。

To meet the requirement of detecting weak Global Position System （GPS） signal indoor, various high sensitivity detection algorithms have been proposed. Chaos oscillator acquisition algorithm belongs to non-linear dynamics and is sensitive to periodic signal and immune to noise. So chaos oscillator algorithm could be utilized to acquire degraded GPS signal. In this paper Dulling chaos oscillator is adopted in the acquisition algorithm and its system property is analyzed. Also Lyapunov exponent is adopted to aid the judgment on the state of chaos oscillator system, and numeric iteration procedure is used to calculate the exponent. Simulation result confirms that comparing with traditional linear GPS signal acquisition algorithm, chaos oscillator acquisition algorithm can achieve the goal of acquiring extremely weak GPS signal and consumes shorter time. These strong points endow the proposed oscillator algorithm a good prospect in the field of weak GPS signal acquisition.