Patent ID: 8872697

Claim:
A method of reconstructing collected data acquired in a three dimensional cylindrical radar scan geometry in which targets are considered to be at near field distances and where the scan planes are defined along a z axis, scan locations are arranged in a circular pattern with a radius R at each plane, an irradiating antenna is facing towards a center of each scan plane, and a waveform f(t) with a prescribed bandwidth is sequentially radiated from each scan location, the method comprising: expressing a received signal from each scan location (R, θ, z) as: s ⁡ ( t , θ , z ) = ∑ q = 1 T ⁢ σ q ⁢ f ⁡ ( t - 2 ⁢ ⁢ D q ⁡ ( θ , z ) v ) where νis the propagation speed, σ q and (r p , φ q , z p ) are the reflectivity and location of the q th target and D q (θ, z )=√{square root over ( R 2 +r q 2 +( z q −z ) 2 −2 Rr q cos(φ q −θ))}{square root over ( R 2 +r q 2 +( z q −z ) 2 −2 Rr q cos(φ q −θ))}; calculating a Fourier transform along the t, z and θ directions of said received signal; applying a filter such that a resulting compensated dataset U(ω, ∈, k z ) is expressed as: U ⁡ ( ω , ɛ , k z ) = ∑ q = 1 T ⁢ 4 ⁢ ⁢ σ q · ξ ⁡ ( ω , ɛ , k z ) · exp ⁡ ( - j ⁡ ( ( 4 ⁢ ⁢ k 2 - k z 2 ) ⁢ r q 2 - ɛ 2 ) + ɛ · sin - 1 ⁡ ( ɛ / ( 4 ⁢ ⁢ k 2 - k z 2 ) ⁢ r q 2 ) + ɛ ⁢ ⁢ ϕ q + k z ⁢ z q ) where ∈ and k z are the spatial frequency counterparts of θ and z respectively and ξ(ω, ∈, k z ) is the spectrum amplitude component in the (ω, ∈, k z ) frequency space; applying a mapping function to the resulting compensated dataset to produce a sampled frequency space denoted as I(k ux , k uy , k z ); interpolating values of I(k ux , k uy , k z ) at points defined in (k x , k y , k z ); and calculating a three dimensional inverse Fourier transform of I(k x , k y , k z ) to yield a three dimensional model i(x, y, z).