Patent ID: 7286083

Claim:
A method for improving signal fault detection and exclusion of a global positioning system (GPS) receiver, at a current epoch, the method comprising: determining pseudorange measurements of a plurality of tracked signals between space vehicles and the GPS receiver; predicting range values corresponding to the plurality of tracked signals; dividing the plurality of tracked signals into two groups, a first group of signals comprising signals with prior epoch pseudorange measurements used in position, velocity and time (PVT) determinations, a second group of signals comprising signals with prior epoch pseudorange measurements not used in PVT determinations or that are newly acquired; evaluating range residuals of tracked signals, the range residuals corresponding to differences between the pseudorange measurements and the predicted range values; estimating a residual bias by utilizing the first group signals; removing the residual bias from evaluated range residuals; comparing each range residual of the first group of tracked signals to a first predetermined threshold value; comparing each positive range residual of the second group of tracked signals to a second predetermined threshold value, and comparing a magnitude of each non-positive measurement residual of the second group of tracked signals to a third predetermined threshold value; and determining PVT values of the GPS receiver position utilizing range measurements of signals whose corresponding range residual magnitudes are less than corresponding threshold values.