Patent ID: 6668218
Filing Date: 2003-12-23
Classification: G01S

Abstract:
A method of estimating a minimum range to a target, comprising:a. obtaining at least three bearing data points of the target with respect to an ownship; b. using the three bearing data points to determine a speed contribution Vos of a first point of interest to a distance from a relative velocity vector over a time frame comprising an initial time t0 to a predetermined time ti; c. determining an angle &thgr;&bgr; as defined as the bearing relative to the ownship's heading at the point in time of closest approach to a second point of interest; and d. calculating a minimum range Min RCPA using the formula Min RCPA=Vos(t&bgr;âˆ’ti)cos(&thgr;&bgr;âˆ’&thgr;i)&thgr;i|=0 e. wherein t&bgr; is the time at which &thgr;&bgr; was measured and &thgr;i is a bearing angle to the target relative to the ownship at time ti.