Method and apparatus for calibrating azimuth boresight in a radar system

A method of calibrating a boresight of a radar antenna in a radar system, comprising the steps of:

• a) selecting a calibration target for use in calibrating the antenna boresight;
• b) obtaining an initial measurement of the selected calibration target's range and azimuth angle at a first time instance;
• c) obtaining subsequent measurements of the selected calibration target's range and azimuth angle at successive time instances subsequent to the first time instance;
• d) calculating a boresight offset angle .alpha. using the initial and subsequent target range and azimuth angle measurements;
• and
• e) calibrating the antenna boresight to compensate for the boresight offset angle calculated in step (d).

A method of calibrating a boresight of a radar antenna in a vehicular radar system, wherein the radar system is deployed on a host vehicle, and wherein the host vehicle travels upon a road and has a known heading, comprising the steps of:

• a) selecting a qualified calibration target vehicle that is substantially aligned with the host vehicle's heading for use in calibrating the antenna boresight;
• b) obtaining an initial measurement of the calibration target azimuth angle at a first time instance;
• c) obtaining a subsequent measurement of the calibration target azimuth angle at a second time instance;
• d) estimating a boresight offset angle .alpha. based upon the initial and subsequent calibration target azimuth angle measurements;
• and
• e) calibrating the antenna boresight to compensate for the boresight offset angle calculated in step (d).

A method of calibrating a boresight of a radar antenna in a vehicular radar system, wherein the radar system is deployed on a host vehicle, and wherein the host vehicle travels upon a road and has a known heading, comprising the steps of:

• a) selecting a qualified calibration target vehicle that is substantially aligned with the host vehicle's heading for use in calibrating the antenna boresight;
• b) obtaining an initial measurement of the calibration target azimuth angle at a first time instance;
• c) obtaining subsequent measurements of the calibration target azimuth angle at successive time instances subsequent to the first time instance;
• d) estimating a boresight offset angle .alpha. based upon the initial and subsequent calibration target azimuth angle measurements;
• and
• e) calibrating the antenna boresight to compensate for the boresight offset angle estimated in step (d).

An apparatus for calibrating an antenna boresight in a radar system, comprising:

• a) means for selecting a calibration target for use in calibrating the antenna boresight;
• b) means, responsive to the selecting means, for obtaining an initial measurement of the target range and azimuth angle at a first time instance;
• c) means, responsive to the selecting means, for obtaining subsequent measurements of the target range and azimuth angle at successive time instances subsequent to the first time instance;
• d) means, responsive to the obtaining means, for calculating a boresight offset angle .alpha. using the initial and subsequent target range and azimuth angle measurements;
• and
• e) means, for calibrating the antenna boresight to compensate for the calculated boresight offset angle.

An apparatus for calibrating a boresight of a radar antenna for use in a vehicular radar system, wherein the radar system is deployed on a host vehicle, and wherein the host vehicle travels upon a road and has a known heading, comprising:

• a) means for selecting a qualified calibration target that is substantially aligned with the host vehicle's heading for use in calibrating the antenna boresight;
• b) means, responsive to the selecting means, for obtaining an initial measurement of the calibration target azimuth angle at a first time instance;
• c) means, responsive to the selecting means, for obtaining subsequent measurements of the calibration target azimuth angle at successive time instances subsequent to the first time instance;
• d) means, responsive to the obtaining means, for estimating a boresight offset angle .alpha. based upon the initial and subsequent calibration target azimuth angle measurements;
• and
• e) means, for calibrating the antenna boresight to compensate for the estimated boresight offset angle.

A computer program executable on a general purpose computing device, wherein the program is capable of calibrating a boresight of a radar antenna in a radar system, comprising:

• a) a first set of instructions for selecting a calibration target for use in calibrating the antenna boresight;
• b) a second set of instructions for obtaining an initial measurement of the calibration target's range and azimuth angle at a first time instance;
• c) a third set of instructions for obtaining subsequent measurements of the calibration target's range and azimuth angle at successive time instances subsequent to the first time instance;
• d) a fourth set of instructions for calculating a boresight offset angle .alpha. using the initial and subsequent target range and azimuth angle measurements;
• and
• e) a fifth set of instructions for calibrating the antenna boresight to compensate for the calculated boresight offset angle.

A method of calibrating a boresight of a radar antenna in a vehicular radar system, wherein the radar system is deployed on a host vehicle, and wherein the radar system is capable of obtaining target azimuth angle measurements from targets detected by the radar antenna, and wherein the radar system maintains an azimuth angle 5 histogram, the histogram having a plurality of bins associated and corresponding to a set of discrete target azimuth angles, comprising the steps of:

• a) initializing an azimuth histogram such that each azimuth angle bin is set to zero, except that a bin associated with a zero degree target azimuth angle is set to a pre-determined maximum histogram count;
• b) receiving target data and obtaining a target azimuth angle measurement;
• c) qualifying the azimuth angle measurement obtained at step (b);
• d) if the azimuth angle measurement qualifies, adding a count to the target azimuth angle bin corresponding to the qualified azimuth angle measurement;
• e) determining whether the histogram contains a pre-determined maximum number of counts;
• f) returning to step (b) if the histogram does not contain the maximum number of counts, otherwise, determining the antenna boresight offset angle from the azimuth angle bin having the highest number of counts;
• and
• g) calibrating the antenna boresight using the boresight offset angle determined in step (f).