US 12,405,357 B2
Pulsed-coherent electronic front end for lidar and radar detection and ranging
Chihkong Yang, Los Angeles, CA (US); and Liyang Chen, Los Angeles, CA (US)
Assigned to The Regents of the University of California, Oakland, CA (US)
Appl. No. 17/597,459
Filed by The Regents of the University of California, Oakland, CA (US)
PCT Filed Jul. 9, 2020, PCT No. PCT/US2020/041443
§ 371(c)(1), (2) Date Jan. 6, 2022,
PCT Pub. No. WO2021/007454, PCT Pub. Date Jan. 14, 2021.
Claims priority of provisional application 62/872,126, filed on Jul. 9, 2019.
Prior Publication US 2022/0252702 A1, Aug. 11, 2022
Int. Cl. G01S 7/48 (2006.01); G01S 7/4865 (2020.01); G01S 17/14 (2020.01)
CPC G01S 7/4865 (2013.01) [G01S 17/14 (2020.01)] 16 Claims
OG exemplary drawing
 
1. A light detection and ranging (lidar) system utilizing both coherent and pulsed detection for Time of Flight (ToF) measurement, comprising:
a reference clock providing a clock signal (CKref) with time period Tclk;
an automatic gain control (AGC) loop that is triggered when a received signal RFin is greater than a threshold voltage Vth;
a coherent detector configured to measure a fine ToF by detecting the phase difference (Δϕ) between the clock signal (CKref) and the received signal (RFin);
a pulse edge detector configured to measure a coarse ToF by detecting a falling edge (post-edge) of the received signal (RFin) and counting cycles N to estimate an arrival time of N×Tclk; and
a combiner configured to calculate total ToF by combining output of the coherent detector and pulse edge detector using the equation:

OG Complex Work Unit Math