Techniques are provided for improved precision timekeeping for a
global positioning system (GPS)
receiver. A methodology implementing the techniques according to an embodiment includes generating a
system clock signal at a reference frequency, the
system clock signal having a first frequency stability. The method also includes generating an auxiliary
clock signal at an auxiliary clock frequency, the auxiliary
clock signal having a second frequency stability that is greater than the first frequency stability, wherein the auxiliary clock frequency differs from the reference frequency by a
frequency offset. The method further includes calculating corrections to the auxiliary
clock signal based on a measure of error in the
frequency offset and on an estimate of error in the auxiliary clock frequency. The method further includes using the calculated corrections to generate a timing signal, during absence of received GPS
satellite signals (e.g., during times when less than four
satellite signals are received).