A Two-Stage Interference Suppression Scheme Based on Antenna Array for GNSS Jamming and Spoofing

. 2019 Sep 7;19(18):3870. doi: 10.3390/s19183870

Algorithm 1 Multiple Interference Suppression Scheme

Jamming Suppression

Input:

x (n T_{s})

(1)
Estimate the spatial covariance matrix ${\hat{R}}_{x} = \frac{1}{K} \sum_{k = 0}^{K - 1} x (k T_{s}) x^{H} (k T_{s})$ .
(2)
Compute the EVD of ${\hat{R}}_{x}$ , and obtain the jamming subspace $V_{J}$ and its orthogonal subspace $P_{⊥}^{J}$ .
(3)
Project the received signal onto the jamming-free subspace $y (n T_{s}) = P_{⊥}^{J} x (n T_{s})$ .

Output:

y (n T_{s}), P_{⊥}^{J}, M^{J}

Spoofing Detection and Mitigation

Input:

y (n T_{s}), P_{⊥}^{J}, M^{J}

(1)
Estimate the cyclic correlation matrix by Equation (28).
(2)
Compute the EVD of ${\hat{R}}_{y}^{c}$ and obtain the eigenvalues and eigenvectors of the signal subspace ${\hat{λ}}_{i}, {\hat{u}}_{i} (i = 1, \dots, \hat{d})$ .
(3)
Compute the test statistic $T_{s s e}$ based on the CCET algorithm.
(4)
Decision. If $T_{s s e} > η$ , then the spoofing signals exist; otherwise, there is no spoofing signal.
(5)
Estimate the spoofing steering vector ${\hat{b}}^{S}$ and the authentic steering vectors ${\hat{b}}_{i}^{A} (i = 1, \dots, \hat{d} - 1)$ by the Cyclic MUSIC algorithm.
(6)
Compute the array weight vector for each satellite signal $w_{i}^{H} = {({\hat{b}}_{i}^{A})}^{H} P_{⊥}^{S}$ (under $H_{1}$ ) or $w_{i}^{H} = {({\hat{b}}_{i}^{A})}^{H}$ (under $H_{0}$ )
(7)
Obtain the output signal $z_{i} (n T_{s}) = w_{i}^{H} y (n T_{s})$

Output:

z_{i} (n T_{s})