Method and system for determining the position of a user device in relation to a vehicle

A system for determining a position of a user device in relation to a vehicle, the system comprising;

• a user device comprising a transmitter and a receiver, the user device being configured to transmit a positioning signal;
• a first receiver, a second receiver, and a control unit adapted to be mounted in a vehicle, the first and second receivers configured to receive the positioning signal transmitted by the user device and to receive and identify at least one reflected positioning signal having been reflected before reaching the first and second receivers, wherein information acquired by parking sensors of the vehicle is used to evaluate a probability that the reflected positioning signal has been reflected at a ground surface, the control unit being configured to initiate and perform time synchronization between the user device and the first and second receivers and to determine a position of the user device in a three-dimensional coordinate system based on a time-of-flight of the positioning signal received in the first and second receivers and on a time-of-flight of the at least one reflected positioning signal received by at least one of the first and second receivers, wherein an uncertainty is included in the determined position in response to a probability that the at least one reflected positioning signal has been reflected at a non-ground surface exceeds a threshold value.

A system for determining a position of a user device in relation to a vehicle, the user device comprising a transmitter and a receiver and being configured to transmit a positioning signal, the system comprising:

• a first receiver adapted to be mounted in a vehicle;
• a second receiver adapted to be mounted in a vehicle;
• and
• a control unit adapted to be mounted in a vehicle;
• wherein the first and second receivers are configured to receive the positioning signal transmitted by the user device and to receive and identify a reflected positioning signal having been reflected before reaching the first and second receivers, wherein information acquired by parking sensors of the vehicle is used to evaluate a probability that the reflected positioning signal has been reflected at a ground surface, the control unit being configured to initiate and perform time synchronization between the user device and the first and second receivers and to determine a position of the user device in a three-dimensional coordinate system based on a time-of-flight of the positioning signal received in the first and second receivers and on a time-of-flight of the reflected positioning signal received by at least one of the first and second receivers, wherein an uncertainty is included in the determined position in response to a probability that the at least one reflected positioning signal has been reflected at a non-ground surface exceeds a threshold value.