Remote Oscillator Characterisation Method for Netted Radar Systems

A method to characterise a remote local oscillator from a radar transmitter of choice is described. It is achieved by sampling a transmitted signal with an USRP at selected time intervals. With the intention to save processing resources, after a first coarse estimation of the transmitted signal periodicity, recursively smaller sampling windows at selected time intervals are being used. The developed algorithm updates a selection window and chooses the most likely time of arrival within the sampled period, with a comparison to the previous measurements. The proposed method saves RF front-end utilisation time while allowing a real-time oscillator characterisation to be remotely carried-out. Sampling occurs at selected time intervals and allows to interleave the characterisation function with other radar modes of operation. At the expense of a lower oscillator characterisation accuracy when compared to characterising the remote oscillator with laboratory equipment using a larger sampling rate, the source remote oscillator may be characterised within a shorter period of time after a certain number of successful measurements. This method enables each receiver within a netted radar to periodically maintain a statistic regarding the behaviour of the local oscillator used by each transmitter of interest. It serves the purpose to provide side information regarding clock stability to aid the time synchronisation process between a receiver and a transmitter of choice.