Method for determining at least one object information item of at least one target object which is sensed with a radar system, in particular of a vehicle, radar system and driver assistance system

A method for determining at least one object information item of at least one target object which is sensed with a radar system of a vehicle, the method comprising:

• transmitting transmission signals into a monitoring range of the radar system with at least one transmitter;
• receiving echoes of the transmission signals, which are reflected at the at least one target object, as received signals with at least one receiver;
• and converting the received signals into a form useable by an electronic control and/or evaluation device;
• wherein the received signals are subjected to at least one multi-dimensional discrete Fourier transformation,
• determining at least one target signal from the result of the at least one Fourier transformation;
• determining at least one object information item from the at least one target signal;
• and
• generating, at the transmitter end, at least one first transmission signal and at least one second transmission signal from a frequency-modulated continuous wave signal, wherein the at least one second transmission signal is encoded by phase modulation with respect to the at least one first transmission signal, with the result that an at least temporary signal orthogonality between the at least one first transmission signal and the at least one second transmission signal is obtained,
• wherein the at least one first transmission signal is emitted with at least one first transmitter, and the at least one second transmission signal is emitted with at least one second transmitter, simultaneously into the monitoring range of the radar system, wherein the at least one second transmission signal is emitted with regular transmission pauses of a predefined length;
• and
• wherein for at least one target spectrum value:
• a difference between the complex-valued amplitudes (s(k, l)) of the cells which are associated with this target spectrum value and have the lowest Doppler value (l) and the third-lowest Doppler value (l) is formed, and the absolute value of this difference is squared and assigned to a first comparison value (X0),
• and a difference between the complex-valued amplitudes (s(k, l)) of the cells which are associated with this target spectrum value (azk,lt) and have the second-lowest Doppler value (l) and the highest Doppler value (l) is formed, and the absolute value of this difference is squared and assigned to a second comparison value (X1),
• the comparison values (X0, X1) are compared and the signals which are associated with the cells from whose amplitudes (s(k, l)) the lower of the two comparison values (X0, X1) is formed are validated as the two target signals which originate from the at least one second transmission signal, for the same target object,
• the absolute values of the amplitudes (s(k, l)) of the cells which are not used to form the lowest comparison value (X0, X1) are compared, and the signal which is associated with the cell with the largest amplitude (s(k, l)) in absolute terms is validated for the same target object as the target signal which originates from the at least one first transmission signal.