|Abstract:||Adaptive arrays have been widely used for interference mitigation in Global Navigation Satellite System (GNSS) receivers. Unlike adaptive nulling, adaptive beam-forming generates a dedicated beam in the antenna pattern towards each individual satellite and form nulls in the interference directions at the same time. Thus, the satellite signals are enhanced while interferences are mitigated, resulting in improved signal-to-interference-plus-noise ratio (SINR). In previous literature mainly two categories of beam-forming mechanisms are recommended, namely the array synthesis method and the so-called “blind” beam-forming method. The array synthesis method calculates the steering vector directly, but needs a cumbersome correction procedure dealing with the non-ideal factors of the antenna array and radio frequency (RF) channels. The blind beam-forming method generates the steering vector on-the-fly using carrier phases collected by auxiliary tracking channels, thus avoids the correction procedure, but has a limited performance against interferences. As an alternative, we proposed a different beam-forming method, which can be regarded as a combination of the two above. This method consists of two steps. In the calibration step, a carrier phase look up table (LUT) is obtained using the live-sky signals. In the beam-forming step, the steering vector is generated by looking up the LUT. This method doesn’t need a cumbersome non-ideal factor correction procedure, and has a good anti-interference performance, thus can be a third option for beam-forming. In order to implement and validate this method, a software-defined approach is used. Two real-time software receivers, one for the calibration step and one for the beam-forming step are designed and implemented. In order to meet the real-time requirement, a graphics processing unit (GPU) is used as an accelerator. A batched programming technique is used to fully take advantage of the parallelism offered by the GPU. Software design and programming details are introduced. Experiments are conducted in real environment and results are given. It concludes that this method has a good beam-forming performance in improving C/N0 and getting more precise positioning results.|
Proceedings of the 2016 International Technical Meeting of The Institute of Navigation
January 25 - 28, 2016
Hyatt Regency Monterey
|Pages:||793 - 804|
|Cite this article:||
Xu, Hailong, Cui, Xiaowei, Shen, Jiannan, Lu, Mingquan, "A Two-Step Beam-Forming Method Based on Carrier Phases for GNSS Adaptive Array Anti-Jamming," Proceedings of the 2016 International Technical Meeting of The Institute of Navigation, Monterey, California, January 2016, pp. 793-804.
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