Patent ID: 9194956
Filing Date: 2015-11-24
Classification: G01S

Abstract:
1. A radio communications device comprising: a satellite positioning subsystem arranged to determine the device's location based on satellite signals and a frequency converter arranged to apply a downshift in frequency to a received signal; a crystal oscillator arranged to produce an output signal whose frequency acts as a controlling reference for the frequency converter, a processor arranged to intermittently correct the crystal oscillator such that the frequency of its output signal experiences jumps; circuitry configured to detect a jump in the frequency of the output signal of the crystal oscillator; wherein the satellite positioning subsystem is arranged to take account of a detected jump in the frequency of the output signal of the crystal oscillator when determining the device's location; and wherein the device further comprises an additional oscillator and a controller arranged to lock the additional oscillator to the crystal oscillator, wherein the controller is arranged to develop a control signal for the purpose of controlling the additional oscillator and the circuitry configured to detect the jump in the frequency of the output signal of the crystal oscillator is arranged to monitor the control signal for a signature of a jump in the frequency of the output signal of the crystal oscillator.