A time-series processor for sonar mapping and novelty detection

A time-series processor chip, intended for sonar mapping and novelty detection applications, has been designed, fabricated and tested. The chip, when coupled with a sonar bearing and range estimation unit, receives an image of the environment as a voltage waveform. The bearing of an object is given by the magnitude of the signal, while its range is given by its time following the transmission of the sonar ´ping´. The chip stores this voltage waveform in a bank of sample-and-hold (S/H) elements and compares it to a previously stored trace. Objects that move in either azimuth or range are immediately detected and reported. The chip contains 54 S/H elements that are triggered by an on-board timer. The change detector can detect motion in bearing and range of 10 degrees/s and 11 cm/s, respectively. The maximum range is approximately 5 m. Operating in the CMOS subthreshold region of operation, the novelty detection chip is designed for ultra-low power and micro-footprint smart surveillance systems. Implemented in a CMOS 0.5 um process, it consumes less than 20 uW @ 8 Hz repetition rate (and less than 6 uW quiescent) with a 3 V supply and occupies less than 0.3 sq. mm.