AbstractTrilateration computationsof radar measurements made between surface ship‐based interrogator‐responsors and shore‐based transponders can be used to obtain better than two‐foot positional accuracy at line‐of‐sight ranges of the order of five miles. Use of nanosecond pulses provides elimination of the usual range errors caused by multipath reflections from sea surface and ship's superstructure. A description of currently available hardware to accomplish these positional accuracies i