Detection of frequency hopping signals via adaptive multichannel radiometry

The authors present an adaptive multichannel radiometer designed to detect frequency hopping (FH) signals in complex signal environments. This is accomplished by having each channel update its hop threshold to reflect the current environment and excise any persistent activity inconsistent with an FH signal from subsequent processing. This strategy allows the receiver to discriminate FH signals from any random noise or interference activity with relatively small degradations as compared to operation in additive white Gaussian noise. Two data collection schemes are considered for the proposed receiver, both of which attempt overall decisions using fixed-length blocks of data. In the first scheme, `block detection´, successive decisions are based on consecutive, nonoverlapping blocks of data, while in the second, block-sequential detection, decisions are made each time a new datum is collected. The block-sequential scheme is shown to offer greatly reduced average detection times