This article contains a discussion of correlation detection in which the coherent processing interval is limited by source/receiver accelerations and/or medium instabilities. A method is described, which, in effect, computes ann‐dimensional correlation function uniquely related to target trajectory. Groups of relatively short waveforms that are individually insensitive to source accelerations, etc., are, after coherent reception, combined via pattern‐recognition techniques. Curves are presented that give the processing gain of the method for various conditions. A numerical example is given for the sonar case.