Daneshmand Saeed, Jahromi Ali Jafarnia, Broumandan Ali, Lachapelle Gérard
PLAN Group, Department of Geomatics Engineering, Schulich School of Engineering, University of Calgary, 2500 University Drive, N.W., Calgary, AB T2N 1N4, Canada.
Sensors (Basel). 2015 May 26;15(6):12180-204. doi: 10.3390/s150612180.
The use of Space-Time Processing (STP) in Global Navigation Satellite System (GNSS) applications is gaining significant attention due to its effectiveness for both narrowband and wideband interference suppression. However, the resulting distortion and bias on the cross correlation functions due to space-time filtering is a major limitation of this technique. Employing the steering vector of the GNSS signals in the filter structure can significantly reduce the distortion on cross correlation functions and lead to more accurate pseudorange measurements. This paper proposes a two-stage interference mitigation approach in which the first stage estimates an interference-free subspace before the acquisition and tracking phases and projects all received signals into this subspace. The next stage estimates array attitude parameters based on detecting and employing GNSS signals that are less distorted due to the projection process. Attitude parameters enable the receiver to estimate the steering vector of each satellite signal and use it in the novel distortionless STP filter to significantly reduce distortion and maximize Signal-to-Noise Ratio (SNR). GPS signals were collected using a six-element antenna array under open sky conditions to first calibrate the antenna array. Simulated interfering signals were then added to the digitized samples in software to verify the applicability of the proposed receiver structure and assess its performance for several interference scenarios.
由于空时处理（STP）在全球导航卫星系统（GNSS）应用中对窄带和宽带干扰抑制均有效，因此受到了广泛关注。然而，空时滤波导致的互相关函数失真和偏差是该技术的一个主要限制。在滤波器结构中采用GNSS信号的导向矢量可以显著降低互相关函数的失真，并实现更精确的伪距测量。本文提出了一种两阶段干扰抑制方法，第一阶段在捕获和跟踪阶段之前估计无干扰子空间，并将所有接收信号投影到该子空间中。下一阶段基于检测和采用因投影过程而失真较小的GNSS信号来估计阵列姿态参数。姿态参数使接收机能够估计每个卫星信号的导向矢量，并在新型无失真STP滤波器中使用它，以显著降低失真并最大化信噪比（SNR）。在开阔天空条件下使用六元天线阵列采集GPS信号，首先对阵列进行校准。然后在软件中将模拟干扰信号添加到数字化样本中，以验证所提出的接收机结构的适用性，并评估其在几种干扰场景下的性能。
