Patent ID: 7994964

Claim:
Method for determining by an electromagnetic detection system an elevation of a target close to a ground, comprising the steps of: receiving, by a reception antenna, a first signal emitted directly by a target; receiving, by the reception antenna, a second signal emitted by the target towards the ground then reflected by the ground toward the electromagnetic detection system, wherein the reception antenna comprises a plurality of sub-arrays of radiating elements; sampling an interference signal produced by the first signal and by the second signal at the level of the sub-arrays, to produce a sampled interference signal; and determining the elevation of the target from an amplitude of the sampled interference signal, wherein a frequency f of the sampled signal is a value which minimizes a function: J ⁡ ( U ) = ∑ i , k ⁢  r i + k + r i - k - 2 ⁢ r i ⁢ cos ⁡ ( 2 ⁢ π ⁢ ⁢ Uk ⁢ ⁢ Δ )  wherein r i+k is a subtraction between a value of a signal received at sub-array i+k and the value of the signal received at sub-array i+k+1, r i−k is a subtraction between the value of the signal received at sub-array i−k and the value of the signal received at sub-array i−k−1, and Δ is a distance between the phase centers of two consecutive sub-arrays.