Vehicle radar system arranged for determining an unoccupied domain

1. A method for a vehicle radar system, where the method comprises the steps of:

generating and transmitting radar signals by a transceiver arrangement;

receiving reflected radar signals, where the transmitted radar signals have been reflected by one or more target objects, where the radar signals form a plurality of sensing sectors, defining related sensing bins having non-uniform angular sizes, that together form a transceiver coverage,

obtaining a target angle and a target range to the one or more target objects for each of the sensing bin; and

determining an unoccupied domain border and a corresponding unoccupied area for the radar transceiver coverage;

wherein each of the sensing bins defines a region having a common vertex located at or adjacent to the transceiver arrangement; and

wherein the method further comprises a smoothing procedure having the steps of:

interpolating a line between Cartesian coordinates of two of the sensing bins defining an intermediate bin therebetween, the Cartesian coordinates of each sensing bin being defined by a center angle and a range value; and

smoothing the intermediate bin in response to a Euclidean distance between the Cartesian coordinates of the two of the sensing bins being less than a predetermined value, wherein smoothing the intermediate bin includes determining a smoothing threshold based on the line between the Cartesian coordinates of the two of the sensing bins, and limiting a range value of the intermediate bin not to exceed the smoothing threshold value.

2. The method according to claim 1 , wherein the method further comprises independently conducting pre-classification of the detections of the one or more target objects into moving or stationary detections.

3. The method according to claim 2 , further comprising, the pre-classification is performed by analyzing the Doppler velocity and the angle of the target object with respect to the motion and the yaw rate of a vehicle.

4. The method according to claim 1 , wherein the method comprises storing detections of the target objects observed in a certain number of radar cycles.

5. The method according to claim 4 , wherein the method further comprises calculating the unoccupied domain border in each of the sensing bins by choosing the target object which is a closest stationary target object in each of the sensing bins within a set of all stored detections of the target objects.

6. The method according to claim 5 , wherein the unoccupied area border extends between the stored detections.

7. The method according to claim 1 , wherein each of the sensing bins is non-overlapping with any other ones of the sensing bins.

8. A vehicle radar system comprising at least one transceiver arrangement configured to generate and transmitted radar signals, and to receive reflected radar signals, where the transmitted radar signals have been reflected by one or more target objects, where the transmitted and reflected radar signals form a plurality of sensing sectors defining a plurality of related sensing bins that together form a transceiver coverage, for each sensing bin the radar system is configured to obtain a target angle and a target range to the one or more target objects, where the radar system further is configured to determine an unoccupied domain border and a corresponding unoccupied domain for the transceiver coverage, and wherein each of the sensing bins defines a region having a common vertex located at or adjacent to the transceiver arrangement;

wherein the vehicle radar system is configured to perform a smoothing procedure that includes:

interpolating a line between Cartesian coordinates of two of the sensing bins forming an intermediate bin therebetween, the Cartesian coordinates of each sensing bin being defined by a center angle and a range value; and

smoothing the intermediate bin in response to a Euclidean distance between the Cartesian coordinates of the two of the sensing bins being less than a predetermined value, wherein smoothing the intermediate bin includes determining a smoothing threshold based on the line between the Cartesian coordinates of the two of the sensing bins, and limiting a range value of the intermediate bin not to exceed the smoothing threshold value.

9. The vehicle radar system according to claim 8 , further comprising, that the vehicle radar system is configured to independently conduct pre-classification of the detections of the one or more target objects into moving or stationary detections.

10. The vehicle radar system according to claim 9 , further comprising, the radar system is configured to be installed in a vehicle, and where the radar system is further configured to perform the pre-classification by performing an analysis of the Doppler velocity and the target angle of the target objects with respect to the motion and the yaw rate of the vehicle.

11. The vehicle radar system according to claim 8 , wherein the vehicle radar system further comprises a detection memory that is configured to store detections of the target objects in a certain number of radar cycles.

12. The vehicle radar system according to claim 11 , further comprising, the radar system is configured to calculate the unoccupied domain border in each of the sensing bins by choosing the target object which is a closest stationary target object in each of the sensing bins within a set of all stored detections in the detection memory.

13. The vehicle radar system according to claim 12 , wherein the unoccupied area border extends between the detections.

14. The vehicle radar system according to claim 8 , wherein each of the sensing bins is non-overlapping with any other ones of the sensing bins.