Autonomic subsystems for cognition in Passive Coherent Location

In a previous paper we mentioned that Passive Coherent Location (PCL) can be thought of as Cognitive Radar. The deployment of PCL systems (also known as Passive Bistatic Radar-PBR) is fraught with difficulty, even in the situation of a spatially static network of transmitters and receivers. It is well known that PCL systems have to take into account the strong, direct signals of cooperative and opportunistic transmitters used, and try to use terrain or antenna nulls to mitigate the receiver dynamic range requirements. Receiver position in the terrain also influences the coverage. This results in a complex planning environment requiring propagation prediction tools to assist in selection of the best site. The situation becomes worse when the network of transmitter and receivers becomes dynamic. In this paper, we discuss the cognition and networking requirements for PCL systems consisting of moving transmitters and receivers, forming a cognitive, sensor network. We show that a sensible approach would use the structure of human intelligence, which consists of a higher level integrating function, together with autonomic, lower level, subsystems.

I. Introduction

PCL type radars utilise electromagnetic emissions from transmitters of opportunity or commission. This is similar to the Cognitive Radio concept [6]. In cognitive radio, for example, it was postulated that handsets could cooperate in relaying of signals between peers, forming ad hoc networks, that would rendezvous in clear spots in the spectrum in which the network was immersed. In addition, the network of closer spaced peers would use considerably less power using peer to peer interconnection and relaying. Handsets would require significant cognition capability to carry out this dynamic organisational adaption.