Radar detection systems and methods for detecting permanence of slow targets

A radar detection system comprising:

• a transceiver configured to cyclically transmit a first radar signal in a field of view and cyclically receive a second radar signal originated from reflections of the first radar signal in the field of view,
• a processing unit configured to cyclically generate a detection profile by processing said first and second radar signals, the detection profile representing intensities of the second signal as a function of positions in the field of view, and
• an analysis unit configured to identify targets in the field of view by cyclically analyzing the detection profile,
• wherein the analysis unit is configured, when cyclically analyzing the detection profile, to:
• using a first mode of analysis with lower sensitivity for a first series of cycles, the first mode of analysis being adapted to detect a target entering the field of view,
• end the first series of cycles when a target is detected based on the first mode of analysis,
• use a second mode of analysis with higher sensitivity for a second series of cycles, the second mode of analysis being adapted to detect the stay of a target in the field of view,
• end the second series of cycles if the second mode of analysis cannot detect any target for a predetermined restart time, and
• use the first mode of analysis after the end of the second series of cycles,
• wherein:
• the second mode of analysis comprises:
• generating and cyclically updating a reference profile with complex numerical values by calculating, for each position, a complex mean of the signal intensities of a plurality of detection profiles which cover a time interval between the generation of the reference profile and a current detection cycle,
• cyclically calculating a complex differential contribution given by the complex difference between the detection profile of the current cycle and the reference profile, and
• identifying the targets from the complex differential contribution by, for each position of the field of view:
• determining the maximum and minimum values of phase angles of the complex differential contributions which follow the generation of the reference profile, limited to the complex differential contributions having a higher modulus than a minimum modulus threshold, and
• determining that a target is present if the difference between the maximum and minimum values of the phase angles exceeds a phase threshold.