A navigation system comprises a global positioning satellite receiver to receive at least one global positioning satellite signal and to output global positioning satellite information. The navigation system further comprises a programmable processor, communicatively coupled to the global positioning satellite receiver, to execute software. The navigation system further comprises a clock, communicatively to the programmable processor, to output processor clock information. The software estimates an amount of drift in the processor clock information using the GPS information and adjusts the processor clock information for the amount of drift in order to generate adjusted processor clock information. The software generates a navigation solution as a function of at least the global positioning satellite information and the adjusted processor clock information.