Three-dimensional SAR imaging technique for MMW seekers

This paper presents a new three-dimensional (3D) synthetic aperture radar (SAR) imaging technique which can be used for millimeter wave (MMW) seekers. It utilizes a linear array in transverse motion to synthesize a two-dimensional (2D) synthetic array. Elements of the linear array are fired sequentially (one element at a time), while all elements receive in parallel. A 2D information sequence is computed from the equiphase two-way signal returns. A new signal model based on a third-order Taylor series expansion about incremental relative time, azimuth, elevation and target height is used. Scatterers are detected as peaks in the amplitude spectrum of the information sequence. Detection is performed in two stages. First, all scatterers within a footprint are detected using an incomplete signal model where target height is set to zero. Then, processing using the complete signal model is performed only on range bins containing significant scatterer returns. The difference between the two images is used to measure target height. Computer simulation shows that this technique is accurate and almost impulse invariant. An example is used to demonstrate this approach