Abstract: A method of detecting a target in a scene is described that comprises the step of taking one or more data sets, each data set comprising a plurality of normalised data elements, each normalised data element corresponding to the return from a part of the scene normalised to a reference return for the same part of the scene. The method then involves thresholding (16) at least one of the normalised data elements of each of said one or more data sets. The thresholding step (16) comprises comparing each of the normalised data elements to at least first and second thresholds, wherein the first threshold is greater than the second threshold. The use of one or more confirmation scans (18) in combination with the thresholding step is also described. A radar system is also described that uses the method to detect foreign object debris (FOD) on a surface such as an airport runway.

Abstract: A method of detecting a target in a scene comprises the steps of (a) obtaining a first data set of data elements which correspond to returns from different parts of the scene; and (b) determining a detection threshold for a part of the scene by reference to data elements corresponding to returns to neighbouring parts of the scene; characterized in that (i) the method further comprises the steps of (c) obtaining a second data set of data elements which correspond only to clutter returns from different parts of the scene; and (d) identifying clutter returns in the first data set by comparing the first and second data sets; and (ii) in step (b), data elements identified in step (d) as corresponding to clutter returns are discounted in determining the detection threshold. The method provides for improved target detection the presence of clutter.

Abstract: A method for processing returns from a sensor, such as a radar system, in order to identify targets is provided. The method uses a track before detect routine to integrate data from several scans in order to give better discrimination. In running the track before detect routine however a number of possible target motions are postulated and the data combined accounting for such motions. A result above a threshold may then be indicative to a target present and moving with the postulated velocity. The method gives more accurate target detection as the combined data at the correct target motion postulate is more consistent than transient noise and clutter. Once a target has been identified it is preferably removed from the data set in searching for additional targets.