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# Algorithm for Determining Location of Moving Target

IP.com Disclosure Number: IPCOM000120494D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 4 page(s) / 95K

IBM

## Related People

Gray, CM: AUTHOR [+2]

## Abstract

Target trajectory can be determined with an algorithm that combines the Doppler frequency shift and angle of arrival of signals originating from two sources and scattered by the moving target.

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Algorithm for Determining Location of Moving Target

Target trajectory can be determined with an algorithm
that combines the Doppler frequency shift and angle of arrival of
signals originating from two sources and scattered by the moving
target.

The geometric relationships in three-dimensional (x,y,z) space
of a moving target, two separated signal sources and single receiver
capable of measuring Doppler frequency shift (time rate of change of
signal delay) and angle of arrival are illustrated in the figure.
The target is assumed to be moving in a straight line at constant
speed with an initial position X0=[X(0),Y(0),x,y]T . Position and
velocity at any time can be determined from these trajectory
parameters:
Note, however, z0 and z0 are assumed to be available from some other
source.
Doppler frequency shift and angle of arrival of the scattered signal
from a source i are functions of target position and velocity:
Let:
A = Angle of arrival of the scattered signal at the receiver
di= Doppler frequency shift (time rate of change of phase) of the
signal from surce i (radians per second)
Di= Doppler shift on signal from source i expressed as the time
rate of change of propagation path length (meters/second)

(Image Omitted)

i = Source index (1 or 2) `  c = speed of signal propagation
through the medium (meters/second)
Fi= frequency of source i (hertz)
where

Repeated measurements of the two Doppler shifts and angle of
arrival m...