Modelling paper, 2007

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Title

Simulating and testing autonomous behavior in multiple airborne sensor systems

Abstract:

The Multiple Airborne Sensor Targeting and Evaluation Rig (MASTER) is a high fidelity simulation environment in which data fusion, tracking and sensor management algorithms developed within QinetiQ Ltd. can be demonstrated and evaluated. In this paper we report an observer trajectory planning tool that adds functionality to MASTER.

This trajectory planning tool controls each sensor by applying instantaneous thrusts, the magnitude of which is chosen to gain maximum observability of the target. The target itself has the capability of being evasive, and can switch between a constant velocity model and a number of quantised acceleration models (of varying magnitude).

We use an efficient search technique to determine the thrust that should be applied to each platform at each time step, and the planning horizon can be either one-step (greedy) or two-step.

The measure of performance used in evaluating each potential sensor manoeuvre (thrust) is the posterior Cramer-Rao lower bound (PCRLB), which gives best possible (lowest mean square error) tracking performance.

In this paper we exploit a recent novel approach to approximating the PCRLB for manoeuvring target tracking (Hernandez et al., 2005). The basis of this technique is to replace the multi-modal target probability density function with a best-fitting Gaussian (BFG) distribution. In a recent paper, this approach was shown give an accurate measure of performance that closely matches state-of-the-art filter performance.

Furthermore, a closed-form expression gives the BFG approximation at each sampling time. Hence, the PCRLB can be approximated with a very low computational overhead, and therefore implemented in time critical scenarios.

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Authors:

M. I. Smith, Waterfall Solutions, UK;
M. L. Hernandez, QinetiQ, UK;
M. Cooper, QinetiQ, UK;

Conference:

SPIE Defense and Security Symposium 2007. Conference 6561 : Unmanned systems technology IX,