US 12,442,923 B2
Method of measuring a distance from a target
Stephan Beer, Schaffhausen (CH)
Assigned to AMS Sensors Asia PTE LTD., Singapore (SG)
Appl. No. 17/638,140
Filed by AMS Sensors Asia PTE LTD., Singapore (SG)
PCT Filed Jul. 30, 2020, PCT No. PCT/SG2020/050440
§ 371(c)(1), (2) Date Feb. 24, 2022,
PCT Pub. No. WO2021/050003, PCT Pub. Date Mar. 18, 2021.
Claims priority of provisional application 62/897,624, filed on Sep. 9, 2019.
Prior Publication US 2022/0206146 A1, Jun. 30, 2022
Int. Cl. G01S 17/10 (2020.01); G01S 7/484 (2006.01); G01S 17/894 (2020.01)
CPC G01S 17/10 (2013.01) [G01S 7/484 (2013.01); G01S 17/894 (2020.01)] 19 Claims
OG exemplary drawing
 
1. A method for measuring a distance to a target, the method comprising:
operating an emitter to generate a first pulsed signal and a second pulsed signal in a field of view of the emitter in which a target may be present, the first pulsed signal having a first pulse frequency and the second pulsed signal having a second pulse frequency, the first pulse frequency being different from the second pulse frequency;
operating a detector to detect signals for a pre-determined duration after said first pulsed signal is generated and for a predetermined duration after said second pulsed signal is generated;
storing said detected signals in a memory spanning a period of the first pulsed signal and a period of the second pulsed signal, respectively;
using the detected signals to identify a portion of the first pulsed signal reflected by the target and a portion of the second pulsed signal reflected by the target;
determining a first virtual distance based on a difference between a reference signal and the detection of the portion of the first pulsed signal reflected by the target;
determining a second virtual distance based on a difference between the reference signal and the detection of the portion of the second pulsed signal reflected by the target; and
determining the distance to the target based on a virtual difference corresponding to a difference between the first virtual distance and the second virtual distance,
wherein the step of determining the distance to the target comprises determining a period difference corresponding to a difference between the period of the first pulsed signal and the period of the second pulsed signal.