A Plan for the Development of Inertial Reconstruction of Initial State Clock (IRIS),
COBIT INC INDUSTRY CA
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Increasing utilization of wideband low energyHertz signalling techniques in the electronic communications and allied arts is creating an urgent need for significant improvements in the stability characteristics of small, rugged, low-cost time standards. One approach to obtaining such improvements is to apply currently available sophisticated signal processing techniques to the homely crystal oscillator. The uncompensated crystal oscillator exhibits performance limitations due explicitly and directly to the physical and electrical characteristics of the crystal resonant element. Compensation improves the performance of the oscillator by in effect isolation of the resonator from the external environment. An alternative approach would be to attempt to create a system image of the resonator at a fixed point in time and synthesize the oscillator output from this fixed image. Kalman filtering techniques are utilized to provide initial-state estimation, and a suitable signal synthesis technique produces the time standard output signal. The crystal oscillator runs uncompensated and is merely utilized to obtain data to present to the filter on the current state of the crystal resonator. The paper includes complete generic flow charts of the proposed state estimation process and supporting signal processing. The program of development of a prototype IRIS system is described.