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We have designed and tested a digital receiver suitable for the reception of 6 GHz instantaneous baseband signals. It is based on a Tektronix TADC-1000 12.5-GS/s 8-bit digitiser module, a Tektronix TIPA-3100 HAPS Interposer board and a Synopsys HAPS62-Virtex6 Prototyping Motherboard. This motherboard is also employed for filtering and signal processing. The ADC module uses an external clock from the interposer board and can accept a range of input clock frequencies between 1.6 and 3.125 GHz, resulting in sample rates of between 8 and 12.5 GS/s in single-channel mode. The external clock and digital data are supplied to and processed via the HAPS62 board. A 2048-channel weighted overlap-add (WOLA) and FFT structure separate the input signal into approximately 5-MHz sub-bands to allow subsequent high-resolution processing to obtain continuous spectral information over the input bandwidth.This system meets present-day demands on high-resolution wideband digital back-ends for RF spectrum monitoring. This technology could be part of the next generation wideband signal intercept systems for the future detection, classification and location of modern complex RF signals.

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Target location is a problem where the application of multiple sensors that are geographically distributed can determine or improve the location estimate of a target. If these sensors are capable of cooperative behaviour then the information from each sensor can be autonomously fused to provide an estimate of the target position. The individual sensors may be quite unsophisticated, yet the observation system that is created through cooperation and adaptive networking of these sensors provides sufficient process gain to achieve target location accuracies similar to those of expensive centralised sensor systems.The accuracy of target location estimates depends heavily on the separation distance between the sensors. Large baseline geometry takes advantage of many seemingly unsophisticated bearing measurements that are organised into a coordinated observation system to locate a target.Team formation is one method to address coordination of distributed sensors, data fusion, sensor resource and energy management, and communication link control based on the concept of cooperating machines 1,2,3 . We apply an algorithm for agent team formation 4 inspired by the self-organising behaviour observed in colonies of ants, to the problem of integrating the sensors of a group of networked mini-Autonomous Air Vehicles (AAVs). The mini-AAVs are tasked to locate targets within a region of interest. The challenge we address is to make the location estimation system adaptive to a dynamic environment and robust to failure. Simulation results are presented which address issues in distributed data fusion, sensor resource and energy management, and communication link control, for a group of mini-AAVs.

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