Determining Transmitted Frequency With Moving Receiver
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
The frequency of a stationary transmitter can be computed at a single moving receiver platform from the linear velocity of the rotated receiving antenna and the difference between the detected maximum and minimum frequencies. This capability enables determination of platform motion from the Doppler shift in signal for passive navigation or for locating the transmitter. In Fig. 1, signals from stationary transmitter 1 are detected by rotating antenna 2 on moving platform 3, such as an aircraft. Platform 3 moves at radial velocity VR relative to the transmitter 1 and antenna 2 has a linear velocity VL . When antenna 2 rotates, the detected frequency varies sinusoidally. When moving directly toward transmitter 1, the detected received frequency will be maximum (Image Omitted) where c is the speed of light.