	US 12,228,402 B2
	Systems and methods for calibrating unstable sensors
Michael Dormody, San Jose, CA (US); Ganesh Pattabiraman, Saratoga, CA (US); Abijith Kumar, San Jose, CA (US); Thomas Wolf, Mountain View, CA (US); Gary Parsons, Mclean, VA (US); Christian Gates, Vienna, VA (US); Deepak Joseph, Fairfax, VA (US); and Badrinath Nagarajan, South San Francisco, CA (US)
Assigned to NextNav, LLC, Sunnyvale, CA (US)
Filed by NextNav, LLC, Sunnyvale, CA (US)
Filed on Dec. 14, 2023, as Appl. No. 18/539,991.
Application 18/539,991 is a continuation of application No. 17/644,029, filed on Dec. 13, 2021, granted, now 11,892,295.
Application 17/644,029 is a continuation of application No. 16/684,859, filed on Nov. 15, 2019, granted, now 11,199,406, issued on Dec. 14, 2021.
Application 16/684,859 is a continuation of application No. 15/692,142, filed on Aug. 31, 2017, granted, now 10,514,258, issued on Dec. 24, 2019.
Claims priority of provisional application 62/489,926, filed on Apr. 25, 2017.
Claims priority of provisional application 62/385,911, filed on Sep. 9, 2016.
Prior Publication US 2024/0118081 A1, Apr. 11, 2024
Int. Cl. G01C 17/38 (2006.01); G01C 5/06 (2006.01); G01C 21/10 (2006.01); G01C 21/16 (2006.01); G01C 25/00 (2006.01); G01S 5/00 (2006.01); G01S 5/02 (2010.01); G01S 19/14 (2010.01); G01S 19/40 (2010.01)

CPC G01C 17/38 (2013.01) [G01C 5/06 (2013.01); G01C 21/10 (2013.01); G01C 21/165 (2013.01); G01C 25/00 (2013.01); G01C 25/005 (2013.01); G01S 19/14 (2013.01); G01S 5/012 (2020.05); G01S 5/017 (2020.05); G01S 5/02 (2013.01); G01S 19/40 (2013.01)]

14 Claims

1. A method, comprising:

determining a first estimated altitude of a mobile device without using any measurement from a pressure sensor of the mobile device;

generating a second estimated altitude of the mobile device using a first measurement from the pressure sensor;

estimating a pressure sensor error of the pressure sensor using the first estimated altitude and the second estimated altitude; and

determining a calibration value for adjusting one or more second measurements from the pressure sensor using the pressure sensor error;

wherein the first estimated altitude is determined by:

estimating a non-vertical velocity of the mobile device;

determining whether the estimated velocity exceeds a threshold amount of velocity;

upon determining that the estimated velocity exceeds the threshold amount of velocity, determining that the mobile device is outdoors; and

after determining that the mobile device is outdoors, determining a ground-level altitude, wherein the first estimated altitude is determined using the ground-level altitude or the ground-level altitude adjusted by a predefined value.