Spoofing Suppression For GNSS Based On Multi-antenna Technology

Global Navigation Satellite System(GNSS) could provide high-precision positioning and timing, which has been widely used in military affair and economic fields. However,GNSS is extremely vulnerable to various formats of intentional or unintentional interference.Wherein, spoofing is a serious threat to security applications of GNSS because it has the same format and structure with authentic GNSS signal in time domain and frequency domain.Spoofing can attack GNSS receiver occurring positioning error while GNSS receiver is unaware of it. Therefore, this thesis focuses on researching spoofing suppression algorithm for satellite navigation.The main contributions and innovations of this thesis are the following:First, the thesis summarizes the main features and generation methods of spoofing,establishes spoofing model and array antenna received signal model when GNSS receiver under spoofing attack, and analyzes GNSS receiver performance when existing spoofing and GNSS signals;Second, in the case of single repeat spoofing source, this thesis proposes using conventional beam forming method to estimate spoofing's DOA(Direction of Arrival), then constructed spoofing orthogonal subspace to suppress spoofing;Third, in the case of multiple repeat spoofing sources, this thesis proposes using signal separation theory to estimate spoofing' and GNSS signals' DOAs, then combines with linearly constrainted minimum variance(LCMV) algorithm to nulling spoofing;Fourth, in the case of jamming, repeat spoofing and generate spoofing existing simultaneously, this thesis proposes a novel satellite navigation interference suppression algorithm based on despread respread algorithm. The proposed algorithm uses despread respread algorithm to obtain weight vectors of all visible satellite signals, and then uses correlation of weight vectors to detect and suppress spoofing. The novel spoofing suppression algorithm does not need to know the array manifold in advance and can produce multiple beams which can suppress oppressive interference, repeat spoofing and generate spoofing simultaneously. These features make the algorithm more suitable for practical applications.The effectiveness and robustness of the proposed algorithm in this thesis are demonstrated via numerical results.