| CPC G01P 21/00 (2013.01) [G01C 25/005 (2013.01); G01S 19/14 (2013.01); G01S 19/40 (2013.01); G01S 19/52 (2013.01); G01S 19/53 (2013.01)] | 18 Claims |
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1. An apparatus for calibrating an inertial sensor configured to detect an angular velocity of a vehicle, the vehicle being equipped with at least one reference receiver which receives signals from a plurality of positioning satellites, at least one first receiver which receives signals from the plurality of positioning satellites, and at least one second receiver which receives signals from the plurality of positioning satellites, the apparatus comprising:
a position calculator configured to calculate a first relative position of the first receiver to a position of the reference receiver based on data based on the signals received by the reference receiver from the positioning satellites and data based on the signals received by the first receiver from the positioning satellites, and calculate a second relative position of the second receiver to the position of the reference receiver based on the data based on the signals received by the reference receiver from the positioning satellites and data based on the signals received by the second receiver from the positioning satellites;
an attitude estimator configured to estimate a value for an attitude of the vehicle and a value for a change in attitude of the vehicle based on the first relative position and the second relative position;
an angular velocity estimator configured to estimate a value for an angular velocity of the vehicle based on the value for the attitude of the vehicle estimated by the attitude estimator and the value for the change in attitude of the vehicle estimated by the attitude estimator;
an error estimator configured to, based on the value for the angular velocity of the vehicle estimated by the angular velocity estimator and a value for the angular velocity of the vehicle detected by the inertial sensor, estimate a value for an angular velocity error that is an error between the value for the angular velocity of the vehicle estimated by the angular velocity estimator and the value for the angular velocity of the vehicle detected by the inertial sensor; and
a calibrator configured to calibrate the value for the angular velocity of the vehicle detected by the inertial sensor based on the value for the angular velocity error estimated by the error estimator,
wherein
the first receiver is mounted to the vehicle and disposed to the left of and behind the reference receiver with a fixed distance between the first receiver and the reference receiver, the second receiver is mounted to the vehicle and disposed to the right of and behind the reference receiver with a fixed distance between the second receiver and the reference receiver, and the first receiver and the second receiver are mounted to the vehicle with a fixed distance between the first receiver and the second receiver, and
the attitude estimator is configured to
calculate a predicted value for the attitude of the vehicle at a current time based on the values for the attitude of the vehicle before the current time,
estimate the value for the attitude of the vehicle at the current time based on the predicted value for the attitude of the vehicle calculated, the first relative position, and the second relative position, and
estimate the value for the change in attitude of the vehicle at the current time based on the values for the attitude of the vehicle before the current time and the estimated value for the attitude of the vehicle at the current time.
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