Method and apparatus for monitoring surface deformations of a scenario

A method for monitoring surface deformations of a scenario by means of differential interferometry technique, said method comprising the steps of:

• prearranging a radar sensor comprising at least one transmitting antenna and one receiving antenna arranged to acquire of radar signals, said radar sensor arranged to move along a planar trajectory γ having centre O;
• defining a reference system S having origin in said centre O;
• acquiring by SAR technique said scenario by means of handling said radar sensor along said planar trajectory γ, said radar sensor being configured in such a way that the radiation pattern of said antennas is oriented radially with respect to said centre O, said acquisition occurring at points of acquisition si arranged on said trajectory γ, obtaining a plurality of data for each point of acquisition si;
• defining a plurality of target points ti of said scenario, the three-dimensional position of each target point ti being definable by means of spherical coordinates (ρi,θi,βi) referring to said reference system S, being known the values of said coordinates ρi and θi;
• acquiring a three-dimensional mapping of said scenario, said mapping comprising a cloud of highlights ρi arranged to define a three-dimensional surface Σ superimposable to said scenario, each highlight ρi definable by means of spherical coordinates (ρk,θk,βk) referring to said reference system S;
• three-dimensional determining said target points ti by means of intersection, for each target point ti, between said three-dimensional surface Σ and the locus of points having the coordinates ρi and θi of said target point ti, obtaining a value of βi for each target point ti;
• global focusing each target point ti with respect to its own three-dimensional position definable by said spherical coordinates (ρi,θi,βi), said step of focusing being obtained, for each target point ti, by analyzing data obtained at each point of acquisition si wherein said target point ti is detectable.

An apparatus for monitoring surface deformations of a scenario by means of differential interferometry technique, said apparatus comprising:

• a radar sensor comprising at least one transmitting antenna and one receiving antenna arranged to acquire radar signals;
• a kinematical chain arranged to actuate said radar sensor along a planar trajectory γ having centre O for carrying out an acquisition by means of SAR technique of said scenario, said radar sensor being configured in such a way that the radiation pattern of said antennas is oriented radially with respect to said centre O, said acquisition occurring at points of acquisition si arranged on said trajectory γ, obtaining a plurality of data for each point of acquisition si;
• a control unit arranged to provide the steps of:
• defining a plurality of target points ti of said scenario, the three-dimensional position of each target point ti being definable by means of spherical coordinates (ρi,θi,βi) referring to said reference system S, being known the values of said coordinates ρi and θi, said focusing comprising the steps of:
• three-dimensional determining said target points ti by the steps of:
• focusing at a first height of acquisition hα1 each target point ti with respect to its own position considering a value of A predetermined and equal to β0;
• focusing at a second height of acquisition hα2≠hα1 each target point ti with respect to its own position considering a value of βi predetermined and equal to β0;
• controlling said focusings at the heights of acquisition hα1 and hα2 obtaining a value of said coordinate βi for each target point;
• wherein said control unit is also arranged for carrying out a step of global focusing each target point ti with respect to its own three-dimensional position definable by said spherical coordinates (ρi,θi,βi), said step of focusing being obtained, for each target point ti, by analyzing data obtained at each point of acquisition si wherein said target point ti is detectable.