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We propose a scheme for bistatic radar that uses a chaotic system to generate a wideband FM signal that is reconstructed at the receiver via a conventional phase lock loop. The setup for the bistatic radar includes a 3 state variable drive oscillator at the transmitter and a response oscillator at the receiver. The challenge is in synchronizing the response oscillator of the radar receiver utilizing a scaled version of the transmitted signal s r (t, x) = αs t (t, x) where x is one of three driver oscillator state variables and α is the scaling factor that accounts for antenna gain, system losses, and space propagation. For FM, we also assume that the instantaneous frequency of the received signal, x s , is a scaled version of the Lorenz variable x. Since this additional scaling factor may not be known a priori, the response oscillator must be able to accept the scaled version of x as an input. Thus, to achieve synchronization we utilize a generalized projective synchronization technique that introduces a controller term -μe where μ is a control factor and e is the difference between the response state variable x s and a scaled x. Since demodulation of s r (t) is required to reconstruct the chaotic state variable x, the phase lock loop imposes a limit on the minimum error e. We verify through simulations that, once synchronization is achieved, the short-time correlation of x and x s is high and that the self-noise in the correlation is negligible over long periods of time.

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A publicly available and maintained electromagnetic finite-difference time domain (FDTD) code has been applied to the forward modelling of the response of 1D, 2D and 3D geophysical targets to a vertical magnetic dipole excitation. The FDTD method is used to analyse target responses in the lMHz to 100MHz range, where either conduction or displacement currents may have the controlling role. The response of the geophysical target to the excitation is presented as changes in the magnetic field ellipticity.The results of the FDTD code compare favourably with previously published integral equation solutions of the response of lD targets, and FDTD models calculated with different finite-difference cell sizes are compared to find the effect of model discretization on the solution. The discretization errors, calculated as absolute error in ellipticity, are presented for the different ground geometry models considered, and are, for the most part, below 10% of the integral equation solutions.Finally, the FDTD code is used to calculate the magnetic ellipticity response of a 2D survey and a 3D sounding of complicated geophysical targets. The response of these 2D and 3D targets are too complicated to be verified with integral equation solutions, but show the proper low-and high-frequency responses. lntroduction At present, there is a substantial interest in the use of high-frequency inductive electromagnetic surveys to locate relatively shallow geophysical targets which include targets related to environmental damage assessment and remediation. With operating frequencies lower than most ground-penetrating radar (GPR) frequencies, induction surveys promise a greater depth of penetration, and can react to conductivity contrasts, as well as to contrasts in permittivity. Intuitive prediction of target response may not be easy in this frequency range as the generation of displacement, as well as conduction currents may dominate the target's response.In order to explore the limits of investigation using the lMHz to 100MHz frequency range, as well as to gain insight into survey configuration, the need to 1 Received