8 Array Evaluation: Direction Finding Performance Bounds

As a prelude to describing specific methods for estimating the direction of an arriving HF signal, it is appropriate to consider performance expectations, particularly with respect to DF accuracy and its relationship to the sensor antenna array. Such expectations are most frequently quantified using Cramer-Rao bounds. Such bounds are described and derived in section 8.3. The Cramer-Rao bounds described here are based on array limitations imposed by receiver noise, and as a result, they may provide optimistic performance predictions in situations where receiver noise is not the only performance-limiting consideration. More complex bounds, including, for example, array errors [1], can be formulated; the only one considered in this work is the Weiss-Weinstein bound.