US 12,072,190 B2
Methods and apparatus for calibrating the zero rate output of a sensor
Bryan A. Cook, Silver Spring, MD (US); Yun Li, Mountain View, CA (US); Mark Turner, Mountain View, CA (US); and Douglas Charles Carlson, Mountain View, CA (US)
Assigned to CEVA TECHNOLOGIES, INC., Mountain View, CA (US)
Appl. No. 17/277,011
Filed by CEVA TECHNOLOGIES, INC., Mountain View, CA (US)
PCT Filed Nov. 22, 2019, PCT No. PCT/US2019/062769
§ 371(c)(1), (2) Date Mar. 17, 2021,
PCT Pub. No. WO2020/087088, PCT Pub. Date Apr. 30, 2020.
Claims priority of provisional application 62/856,953, filed on Jun. 4, 2019.
Claims priority of provisional application 62/779,336, filed on Dec. 13, 2018.
Claims priority of provisional application 62/736,355, filed on Sep. 25, 2018.
Prior Publication US 2022/0026214 A1, Jan. 27, 2022
Int. Cl. G01C 21/16 (2006.01); G01C 25/00 (2006.01); G01P 15/18 (2013.01); G01P 21/00 (2006.01); G06F 3/0346 (2013.01)
CPC G01C 21/16 (2013.01) [G01C 25/00 (2013.01); G01P 15/18 (2013.01); G01P 21/00 (2013.01); G06F 3/0346 (2013.01)] 22 Claims
OG exemplary drawing
 
1. A method for calibrating zero rate offset (ZRO) of a first inertial sensor located on a device, the method comprising:
determining a stability level of the device based on information associated with at least one non-inertial sensor located on the device which is used to generate a state of motion signal sent from a controller on the device to an inertial motion unit (IMU);
determining a temperature of the first inertial sensor;
collecting multiple samples of an output of the first inertial sensor during periods when an overall stability status indicates that the device is sufficiently stable for ZRO calibration and the temperature of the first inertial sensor is stable;
estimating the ZRO of the first inertial sensor at the temperature of the first inertial sensor during the collecting as a function of the samples;
determining at least two consecutive discrete periods during which the device is stable and the temperature of the first inertial sensor is stable and substantially the same stable over the at least two consecutive periods;
determining a gap time between the at least two consecutive discrete periods; and
performing a calibration of the ZRO of the first inertial sensor when the stability level is above a first threshold, wherein the performing the calibration of the ZRO of the first inertial sensor comprises, if the gap time is below a second threshold, combining the samples from the at least two consecutive discrete periods to generate a ZRO estimate.