Surveillance apparatus having a radar sensor

A surveillance method for estimating a position of an object among objects in a field of view of a radar sensor, comprising:

• transmitting electromagnetic radiation by at least one transmitting antenna,
• receiving electromagnetic radiation from the field of view by a plurality of receiving antennas,
• receiving signals from the receiving antennas corresponding to the received electromagnetic radiation,
• calculating, using processing circuitry, as a beat frequency, a frequency of mixed signals of the received signals and signals transmitted from the transmitting antenna,
• estimating a correlation matrix on the basis of the received signals,
• estimating a number of the objects in the field of view from the estimated correlation matrix,
• performing a maximum likelihood estimation using the calculated beat frequency, the estimated correlation matrix and the estimated number of the objects to calculate an angle of the object,
• determining whether an angle of the object has been calculated,
• repeating the calculation of the beat frequency, the estimation of the correlation matrix and the number of the objects, and the performance of the maximum likelihood estimation in a case where it is determined that the angle of the object has not been calculated,
• determining frequency peaks in a transformed signal spectrum of the received signals in a case where it is determined that the angle of the object has been calculated,
• determining each distance of the objects in the field of view based on the determined frequency peaks,
• determining a map of amplitudes for different positions in the field of view based on a corresponding plurality of beamformed signals,
• determining a power of signals of the different positions received by the radar sensor based on the determined map and corresponding values of the estimated correlation matrix, and
• outputting the direction, the distance, and the power of signals of the position of the object in the field of view with respect to the radar sensor separately.

A non-transitory computer-readable recording medium including executable instructions, which when executed by a computer cause the computer to execute a method for estimating a position of an object among objects in a field of view of a radar sensor, the method comprising:

• transmitting electromagnetic radiation by at least one transmitting antenna,
• receiving electromagnetic radiation from the field of view by a plurality of receiving antennas,
• receiving signals from the receiving antennas corresponding to the received electromagnetic radiation,
• calculating, as a beat frequency, a frequency of mixed signals of the received signals and signals transmitted from the transmitting antenna,
• estimating a correlation matrix on the basis of the received signals,
• estimating a number of the objects in the field of view from the estimated correlation matrix,
• performing a maximum likelihood estimation using the calculated beat frequency, the estimated correlation matrix and the estimated number of the objects to calculate an angle of the object,
• determining whether an angle of the object has been calculated,
• repeating the calculation of the beat frequency, the estimation of the correlation matrix and the number of the objects, and the performance of the maximum likelihood estimation in a case where it is determined that the angle of the object has not been calculated,
• determining frequency peaks in a transformed signal spectrum of the received signals in a case where it is determined that the angle of the object has been calculated,
• determining each distance of the objects in the field of view based on the determined frequency peaks,
• determining a map of amplitudes for different positions in the field of view based on a corresponding plurality of beamformed signals,
• determining a power of signals of the different positions received by the radar sensor based on the determined map and corresponding values of the estimated correlation matrix, and
• outputting the direction, the distance, and the power of signals of the position of the object in the field of view with respect to the radar sensor separately.