CHARACTERIZING GPS PHASE LOCK LOOP PERFORMANCE IN WIDEBAND INTERFERENCE USING THE DISCRIMINATOR OUTPUT DISTRIBUTION
CHARACTERIZING GPS PHASE LOCK LOOP PERFORMANCE IN WIDEBAND INTERFERENCE USING THE DISCRIMINATOR OUTPUT DISTRIBUTION
复制标题
使用鉴频器输出分布表征宽带干扰中的 GPS 锁相环性能
DOI：
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
S. Stevanovic
中科院分区：
文献类型：
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作者：
S. Stevanovic
近年来，全球定位系统(GPS)的使用速度加快。在其诞生之初，GPS仅由军方用于导航。今天，随着功能极其强大的电子产品和微处理器的出现，GPS已经融入了生活的许多方面。目前，它被军事和各种民用工业广泛用于需要导航和精确计时的应用。GPS的一些应用包括地面车辆和飞机导航、银行、电力传输和农业。因此，GPS可用性的中断有可能扰乱全球许多服务和行业，甚至威胁生命安全。可靠的运行可能会被射频干扰(RFI)中断，这种干扰可能来自自然来源和人为来源。这项工作描述了评估可能受到RFI事件影响的GPS接收机性能的新技术。激励这项工作的示例应用是地面增强系统(GBAS)参考站接收器受到宽带干扰，例如，来自附近使用的个人隐私设备(PPD)的干扰。PPD最常见的是发射宽带干扰，而GBAS地面参考接收器因此经历了跟踪中断[Pul12]。这些事件可能会导致飞机在最终进场时导航服务中断。为了确保导航服务的连续性，GBAS基准站必须能够在存在宽带干扰的情况下跟踪GPS信号。这项工作的目标是开发设计能够跟踪RFI事件的PLL所需的PLL分析工具，同时减少耗时的模拟和实验验证的需要。相反，模拟和实验验证可以保留给更有可能成功的PLL设计。这项工作中描述的技术适用于接收机不能容忍锁相环(PLL)中的周跳的任何GPS应用XIII。该方法直接适用于差分GPS系统的陆基参考接收器，以及其他需要高服务连续性的陆基接收器。如果还考虑了锁相环上的附加动应力，它也与移动接收器有关。与以往工作和文献中广泛使用的相位抖动度量不同，PLL鉴别器输出(DO)分布被用来表征GPS PLL的跟踪性能。在预测锁相方面，DO方差和DO分布均值上的偏差都优于抖动度量。结果表明，DO均值中的偏差是周跳概率的最有效度量。对鉴别器输出分布的研究还提供了一种比较不同技术的方法，以延长PLL平均时间超过导航数据比特的长度，而不需要耗时的直接模拟和实验验证。给出了实验结果，验证了理论分析和仿真的正确性。观测到的跟踪结果与理论预测的系统性能一致。在预测锁相损失方面，DO偏置优于方差度量。
The use of the Global Positioning System (GPS) has accelerated in recent years. In its inception, GPS was used exclusively by the military for navigation. Today, with the emergence of extremely capable electronics and microprocessors, GPS has been integrated into many aspects of life. It is currently widely used by both the military and various civilian industries for applications that require navigation as well as precise timing. Some applications of GPS include ground vehicle and aircraft navigation, banking, power transmission, and agriculture. As a result, disruptions in GPS availability have the potential to disrupt many services and industries around the globe, and even threaten the safety of life. Reliable operation can be interrupted by radio frequency interference (RFI), which can come from natural and manufactured sources. This work describes new techniques to evaluate the performance of GPS receivers that may be subjected to RFI events. The example application motivating this work is Ground Based Augmentation System (GBAS) reference station receivers subjected to broadband interference, for example, from nearby use of personal privacy devices (PPDs). PPDs most commonly emit broadband interference, and GBAS ground based reference receivers have experienced tracking discontinuities as a result [Pul12]. These events can cause navigation service interruptions to aircraft on final approach. To ensure continuity of the navigation service, GBAS reference stations must be able to track GPS signals in the presence of wideband interference. The objective of this work is to develop the PLL analysis tools required to design PLLs capable of tracking through RFI events, while reducing the need for time-consuming simulations and experimental validation. Instead, simulation and experimental validation can be reserved for PLL designs which are much more likely to be successful. The techniques described in this work are valid for any GPS application xiii in which the receiver cannot tolerate cycle slips in the phase-lock loop (PLL). The methodology is directly applicable to ground-based reference receivers for differential GPS systems, as well as other ground-based receivers that require high continuity of service. It is also relevant to moving receivers, if the additional dynamic stresses on the PLL are also taken into account. The PLL discriminator output (DO) distribution is used to characterize GPS PLL tracking performance, in contrast to the phase jitter metric widely used in prior work and literature. Both the DO variance and the bias on the mean of the DO distribution are shown to be superior to the jitter metric in predicting phase-lock. And, it is shown that the bias in the DO mean is the most effective measure of cycle slip probability. Studying the discriminator output distribution also provides a means of comparing different techniques to extend PLL averaging time beyond the length of a navigation data bit, without time-consuming direct simulation and experimental validation. Experimental results are presented to validate the theoretical analysis and simulations. The observed tracking results are consistent with the theoretically predicted system performance. The DO bias is superior to the variance metric in its ability to predict loss of phase-lock.