A method for operating a plurality of GNSS receivers for detecting satellite signal deformation

• Main Authors: Kälberer, Ulrich, Schüttpelz, André, Beck, Frieder, Kusari, Arberita, Bomart, Sébastien
• Format: Patent
• Language: English
• Published: 10.12.2020
• Subjects: ANALOGOUS ARRANGEMENTS USING OTHER WAVES; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION ORRERADIATION OF RADIO WAVES; MEASURING; PHYSICS; RADIO DIRECTION-FINDING; RADIO NAVIGATION; TESTING

Abstract In conclusion, the present invention proposes a test metric for GNSS code 5 signals received at GNSS receivers (1-4), wherein for each satellite i, a signal sent by that satellite i is received at the different GNSS receivers (1-4), and bias-removed, averaged over the receivers and normalized measurement values are derived out of autocorrelation function values (110, 120) from the received GNSS code signals, wherein a correlation matrix Ri,n is built (130) from 10 a matrix X, containing the measurement values in the form of measurement value vectors 'k from the present time epoch to and from previous time epochs tk with k=1,...,n-1, wherein a principal component analysis is done (150) of matrix Ri,n, wherein a transformed vector i PC iscalculated(160), with PCi,n containing at least two eigenvectors belonging to eigenpairs having 15 the largest eigenvalues of all eigenpairs, wherein a signal quality monitor test metric SQMOn is built (170) from the square sum of the entries of transformed vector im, and wherein if SQMn is larger than a threshold THR, the signals of satellite i are disallowed (190) for position determination at all GNSS receivers (1-4). The invention allows monitoring GNSS code signals with respect to 20 satellite signal deformation with an improved integrity and continuity. (Fig. 3) Thales 08.08.2018 SP12536EP Time epoch tn Dermine pmin for satellite i Determine Tn Storage of by bias removal/ ---... k /.R,k / 120 normalization 140 10Determine Ri,n Do PCA of Ri n, obtain Pi,n, , n . _ ____ Determine PCi,n 160 Calculate ?"n Determine 170 SQMi,n Allow no SQMi,n yes Disallow satellite i >THR? satellite 1 200 180 190 Repeat for other satellites 210 Do position determination Next time Fig. 3 220 with allowed satellites epoch n+1 230 Thales 08.08.2018 SP12536EP