Unlike monostatic radars that directly measure the range to a target, multistatic radars measure the total path length from a transmitter, to the target, and then to the receiver. In the absence of angle information, the region of uncertainty described by such a measurement is the surface of an ellipsoid. In order to precisely locate the target, at least three such measurements are needed. In this paper, we derive from geometrical methods a general algorithmic solution to the intersection of three ellipsoids with a common focus. Applying the solution to noisy measurements via the cubature rule provides a solution that approaches the Cramer Rao Lower Bound, which we demonstrate via Monte-Carlo analysis. For conditions of low noise with non-degenerate geometries we also provide a consistent covariance estimate.
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