Direction of arrival estimation for automotive spread radar systems

A method of direction of arrival estimation with an automotive spread radar system, the automotive spread radar system comprising a plurality of at least two transceiver antenna units, which are configured to work in a multiple-input and multiple-output configuration, wherein the transceiver antenna units are arranged at a priori known positions, and the automotive spread radar system is configured to determine, for each specific transceiver antenna unit of the plurality of transceiver antenna units, a range of a target reflecting radar waves that have been transmitted by at least the specific transceiver antenna unit by reading out a plurality of range gates that are assigned to the specific transceiver antenna unit, the method comprising steps of:

• for each specific one of the plurality of transceiver antenna units, determining a range of a target occurring in one of separated angular directions lying within an angular range that is arranged about a common direction at least from radar waves that have been transmitted by the specific transceiver antenna unit and have been reflected by the target, by reading out range gates out of the plurality of range gates of the specific transceiver antenna unit,
• determining a pattern of occupied range gates from the read-out range gates of the plurality of transceiver antenna units, wherein the pattern of occupied range gates are created by mutually shifted range gate allocations of the plurality of transceiver antenna units, and
• estimating a direction of arrival based on relating the determined pattern of occupied range gates to a plurality of expected patterns of occupied range gates for targets occurring in the separated angular directions, the plurality of expected patterns of occupied range gates being predetermined from the a priori known positions of the plurality of transceiver antenna units, and wherein the direction of arrival is estimated without using phase information from reflected radar waves.