Environmentally Adaptive Arctic navigation Signal Processing

The proposed work will focus on combined signal processing and acoustic modeling that will ultimately enable high-accuracy navigation under the Arctic ice at ranges up to and including basin scale. This combined approach is required because as the source-vehicle range increases, the bandwidth of the signals decrease because the carrier frequency must be reduced to enable long-distance communications. The multipath spread and complexity of the signal also increase with range. The aim of the proposed work is to utilize as much of the received wave front information as possible in an effort to improve the range estimate and thus the localization accuracy. The effects of signal scatter off of the sea ice and limited a-priori sound-speed data will be addressed. Automated approaches for processing on-board the platform will be explored. The work builds upon and will extend that being done by WHOI for the ONR Marginal Ice Zone DRI, which will enable Sea Glider navigation to order 1 km and low-rate (several bps) communications. High-resolution acoustic propagation modeling, combining climatic and in-situ data, is essential in order to increase the accuracy and extent by more than an order of magnitude.