Method for robust vehicle occupancy detection with vital sign monitoring

A method of operating a radar sensor system for detecting an occupancy in an interior of a vehicle, with vital sign monitoring;

• the radar sensor system comprising:
• a radar transmitting unit being configured for transmitting radar waves towards a scene within the vehicle interior,
• a radar receiving unit being configured for receiving radar waves that have been transmitted by the radar transmitting unit and have been reflected by an object within the scene, and
• a signal processing and control unit that is at least configured to derive range information, Doppler information and angle-of-arrival information from the received radar waves;
• and the method including at least the following steps, which are to be carried out in an iterative manner:
• operating the radar transmitting unit for transmitting a radar wave towards a scene within the vehicle interior,
• operating the radar receiving unit for receiving at least one radar wave that has been generated by reflection of the transmitted radar wave,
• operating the signal processing and control unit for:
• decomposing the received at least one radar wave into range, Doppler and angular information, and
• detecting and monitoring vital signs of occupants in each region of interest of a plurality of predefined different regions of interest,
• wherein the step of operating the signal processing and control unit includes:
• quantifying and tracking a movement in each region of interest of a plurality of predefined different regions of interest by angular gating and range gating, and
• for each region of interest, determining whether quantified and tracked movements in the scene are related to an occupant or to external or internal disturbances, based on a fulfillment of at least one predefined condition concerning the quantified and tracked movements and/or the detected and monitored vital signs, wherein the at least one predefined condition includes that if movement is present in all or several range regions of interest, a disturbance is likely to be present, and if movement is detected only in a region with a seating position, and vital signs are found, it is determined that the seat is occupied.