Passive range and angle measurement system and method
AssigneeITT Manufacturing Enterprises, Inc.
InventorsMitchell Joseph Sparrow, Joseph Cikalo
Life of this patent
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Abstract
A method determines range from a moving platform to an emitter. The method receives a RF signal from the emitter; counts a number of phase reversals of the received RF signal during a period of time; measures a Doppler frequency during the period of time; and determines the range to the emitter based on both the number of counted phase reversals and the measured Doppler frequency.
Claims20
A method of determining range from a moving platform to an emitter comprising the steps of:
- (a) receiving a RF signal from the emitter;
- (b) counting a number of phase reversals of the received RF signal during a period of time;
- (c) measuring a Doppler frequency during the period of time;
- and
- (d) determining the range to the emitter based on both the number of phase reversals counted in step (b) and the Doppler frequency measured in step (c).
A method of determining range from a moving platform to an emitter comprising the steps of:
- (a) receiving a RF signal from the emitter during a period of time the moving platform traverses a distance, the distance denoted by b;
- (b) determining a carrier wavelength, λ, of the RF signal;
- (c) counting a number of phase reversals of the received RF signal during the period of time, the number denoted by N;
- (d) determining a range differential, ΔR, between the moving platform and the emitter during the period of time, in which
- ΔR=Nλ;
- (e) measuring a Doppler frequency, fd, during the period of time;
- and
- (f) determining the range to the emitter based on the distance b, the range differential ΔR and the Doppler frequency fd.
An apparatus, installed onboard a moving platform, for determining range from the moving platform to an emitter comprising
- a receiver for receiving a RF signal from the emitter,
- an analog to digital converter (ADC) for converting the received RF signal into a digital signal,
- a memory for storing the digital signal provided by the ADC, and
- a processor coupled to the memory for extracting the stored digital signal, and (a) counting a number of phase reversals of the digital signal during a period of time, (b) measuring a Doppler frequency during the period of time, and (c) determining the range to the emitter using both the counted number of phase reversals and the measured Doppler frequency.
Dependencies are inferred from the claim text.