US 2011/0087450 A1 · Heading Error Removal System for Tracking Devices

Abstract

Systems are able to reduce or remove slowly-varying drift errors, such as heading errors, rate of rotation errors, and direction of travel errors, to correct the measurements from tracking devices. The systems may be used to remove the slow varying drift errors for gyroscopic tracking device sensors, or other types of sensors used for determining heading, rates of rotation, direction of travel, or position. The systems may be employed in personal dead reckoning systems, or other personnel tracking device, as well as in vehicle tracking devices. The system uses heuristic assumptions to correct for these drift errors, via a feedback loop control having an accumulator responsive to changes in output signals. The accumulator is able to produce a signal that over time compensates for the inherent drift errors on those output signals.

Claims37

Dependent claims

A method for determining a direction of travel of a tracking device, the method comprising:

receiving measurements from a sensor assembly of the tracking device at a controller of the tracking device;
determining, using the controller, an indication of the direction of travel of the tracking device based on the measurements from the sensor assembly;
and
removing, using the controller, drift error from the indication of the direction of travel of the tracking device, based on a deviation of a previous direction of travel associated with the tracking device from one of a plurality of dominant directions, to generate a corrected indication of the direction of travel of the tracking device.

1 more element

A tracking device comprising:

a sensor assembly;
a memory having computer-executable instructions stored therein;
and
a controller to execute the computer-executable instructions, the computer executable instructions for,
determining an indication of a direction of travel of the tracking device based on measurements from the sensor assembly;
and
removing drift error from the indication of the direction of travel of the tracking device, based on a deviation of a previous direction of travel associated with the tracking device from one of a plurality of dominant directions, to generate a corrected indication of the direction of travel of the tracking device.

4 more elements

A method for removing drift error from a tracking device having a sensor assembly, the method comprising:

receiving measurements from the sensor assembly at a controller of the tracking device;
determining, using the controller, an indication of a direction of travel of the tracking device based on the measurements from the sensor assembly;
supplying the indication of the direction of travel to a closed loop feedback control of the controller that is to perform a low pass filtering on an indication of a previous direction of travel of the tracking device and that is to map the indication of the previous direction of travel onto one of a plurality of dominant directions to form a mapped indication of the previous direction of travel;
an accumulator within the closed loop feedback control accumulating error values corresponding to a difference between the mapped indication of the previous direction of travel and a baseline direction of travel;
the closed loop feedback control producing an integrator signal that counteracts the effects of drift error of within the indication of the direction of travel, wherein the drift error is a normalized drift error that has had static drift error removed;
and
correcting the indication of the direction of travel by applying the integrator signal to the indication of the direction of travel to produce a corrected indication of the direction of travel.

4 more elements

Dependencies are inferred from the claim text.

Heading Error Removal System for Tracking Devices

Life of this patent

Heading Error Removal System for Tracking Devices

Life of this patent

Abstract

Claims37