Abstract: A system includes an input for receiving an input signal, a filter having a changeable time constant, and a control circuit for changing the filter time constant in response to a property of the input signal.

Abstract: An apparatus comprising an array of antenna elements, a beamformer for adjusting signals to and from the elements to form a first beam pattern and a second beam pattern, and wherein the first beam pattern is a sum pattern and the second beam pattern is a null pattern. A method of beamforming for sidelobe cancellation is also provided.

Abstract: A method for determining the height HT of a target above a surface, the method comprising the steps of determining a distance R from a source to a target, determining a distance L representative of a distance traveled by a signal from the target that is reflected by the surface to the source, determining a height H of the source above the surface, and determining the height HT of the target using the equation: H T = ( L 2 - R 2 ) 4 ? H Associated target height errors that result from input errors can also be determined using the equation.