Method and apparatus for detection of an electromagnetic signal reflected from and object

An apparatus comprising:

• a transmitting antenna for transmitting electromagnetic signals,
• at least two essentially identical receiving antennas having a basic alignment in a predetermined direction and being arranged with a distance (d) from each other,
• each receiving antenna having a sensitivity characteristic over reception angles showing a maximum for a reception angle coinciding with the basic alignment of said receiving antennas and having flank falling with increasing reception angle from the basic alignment from said maximum to a minimum each and, with further increasing reception angle from the basic alignment, forming first sidelobes having increasing sensitivities, said sidelobes being arranged symmetrically to said basic alignment, and
• a measurement device for determining the phase differences of the signals being reflected by an object and received by the at least two receiving antennas, the phase differences being determined unambiguously within a certain angle interval, said inteval being determined by the distance (d) between the receiving antennas,
• wherein said distance (d) is chosen so that limits of said certain angle interval intersect the first sidelobes, and
• wherein said measurement device comprises a device which for object detection purposes vectorially adds the signals received by the receiving antennas before the phase differences are determined.