TDOA-based positioning of communication signals - description of a testbed-system with results from field trials

The use of TDOA-based methods for direction finding and positioning of communication signals offer a possibility of producing low complexity systems while maintaining the performance advantage over traditional positioning systems. The TDOA-based methods for positioning show promising results for wideband stealth signals at low SNR. A testbed-system denoted KOBRA is being developed using TDOA-based direction finding and positioning to verify the theoretical results. Positioning of a transmitter is achieved using three receiver systems. Different waveforms have been used, for example a direct-sequence spread-spectrum signal with a bandwidth of 4 MHz and an analog speech signal. The theoretical results for TDOA-based direction finding and positioning are verified using the three channel measurements. That is, high signal bandwidth is of greater importance than high SNR, and positioning of digital wideband signals at very low SNR is possible.