	US 12,153,135 B2
	Methods and apparatuses for range peak pairing and high-accuracy target tracking using FMCW LADAR measurements
Michael James Thorpe, Bozeman, MT (US); and Seth Kreitinger, Bozeman, MT (US)
Assigned to Bridger Photonics, Inc., Bozeman, MT (US)
Appl. No. 17/259,921
Filed by Bridger Photonics, Inc., Bozeman, MT (US)
PCT Filed Jul. 18, 2019, PCT No. PCT/US2019/042422 § 371(c)(1), (2) Date Jan. 12, 2021, PCT Pub. No. WO2020/018805, PCT Pub. Date Jan. 23, 2020.
Claims priority of provisional application 62/700,012, filed on Jul. 18, 2018.
Prior Publication US 2021/0293960 A1, Sep. 23, 2021
Int. Cl. G01C 3/08 (2006.01); G01S 7/4911 (2020.01); G01S 7/4912 (2020.01); G01S 17/34 (2020.01)

CPC G01S 17/34 (2020.01) [G01S 7/4911 (2013.01); G01S 7/4917 (2013.01)]

23 Claims

1. A method comprising:

illuminating a surface with a first laser with a first chirp rate and a first mean optical frequency during a first time and with a second chirp rate during a second time;

illuminating the surface with a second laser with a third chirp rate and a second mean optical frequency during the first time and with a fourth chirp rate during the second time, wherein the second mean optical frequency is different than the first mean optical frequency;

receiving light reflected from the surface and generating a signal with a first portion based on the first laser and the second laser during the first time and a second portion based on the first laser and the second laser during the second time;

combining a first estimated range based on the first portion of the signal with a second estimated range based on the second portion of the signal to determine a final range; and

cancelling a Doppler shift error in the first estimated range and the second estimated range by combining the first estimated range and the second estimated range.