Intercept ranging system test results in an acoustic basin

This paper addresses the localization of active sonar signals that are encountered in the international submarine community with the function of Acoustic Intercept Ranging. An Intercept ranging system was developed by ISL (USA) and TNO (The Netherlands), where ISL was responsible for the system design, the hardware and the integration and TNO developed the software. The intercept ranging system consists of three hydrophones at a relatively long baseline, such that correlation techniques can provide range of the sound source via cross-bearings. The system is able to range sources that transmit narrow or wideband sonar signals, even in complicated multipath environments. To demonstrate the software, experiments were performed by ISL with a down-scaled system in an acoustic basin. This mock-up system proved to provide accurate bearings and ranges in this complex set-up, in which the signals were severely contaminated by multi-path interaction from basin’s walls. Even for narrow band signals for which correlation gain is poor and ranging is often cumbersome, the system showed good results.