Importance

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Abstract

A Doppler position locator for determining the bearing of a signal source from a moving receiver. The signal source encodes a digital signal indicating its actual transmitting frequency on a transmitted carrier. The moving receiver such as an airplane receives a Doppler shifted carrier frequency and the digital information on what the actual transmitted frequency was. Comparison of the received frequency to the digital information on the transmitted frequency yields a Doppler frequency (the increase or decrease caused by the relative motion, i.e., the numerical difference between the transmitted and received frequencies). From the aircraft velocity and the two frequencies, the bearing can be determined using the formula .crclbar.=cos.sup.-1 (d*c)/(f*v) where .crclbar. is the bearing angle, f is the transmitted frequency, d is the Doppler shift or change in frequency, c is the speed of light and v is the magnitude of the receiver velocity. The airplane ground speed is determined independently by conventional navigation techniques.

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First Claim