US 11,921,187 B1
Monitoring non-stationary object distance using ultrasonic signals
Spencer Russell, Quincy, MA (US); Krishna Kamath Koteshwara, Santa Clara, CA (US); Tarun Pruthi, Fremont, CA (US); Trausti Thor Kristjansson, San Jose, CA (US); and Anran Wang, Seattle, WA (US)
Assigned to Amazon Technologies, Inc., Seattle, WA (US)
Filed by Amazon Technologies, Inc., Seattle, WA (US)
Filed on Apr. 16, 2021, as Appl. No. 17/232,649.
Int. Cl. G01S 13/56 (2006.01); G01S 7/40 (2006.01); G01S 13/58 (2006.01); G01S 13/84 (2006.01)
CPC G01S 13/56 (2013.01) [G01S 7/4056 (2013.01); G01S 13/581 (2013.01); G01S 13/584 (2013.01); G01S 13/84 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A monitoring device comprising:
a loudspeaker;
one or more processors; and
one or more computer-readable media storing computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
causing the loudspeaker to emit, during a period of time, frequency-modulated continuous wave (FMCW) ultrasonic signals into an environment, a first FMCW ultrasonic signal having a first portion that increases in frequency in a frequency range and a second portion that decreases in frequency in the frequency range;
receiving reflection signals corresponding to the FMCW ultrasonic signals, the reflection signals originating at an object in motion;
generating, over a plurality of time frames, data including energy values corresponding to the reflection signals;
identifying, for a first time frame, a first energy value that corresponds to a first reflection of the first portion of the first FMCW ultrasonic signal, the first energy value being associated with a first distance;
identifying, for a second time frame adjacent the first time frame, a second energy value that corresponds to a second reflection of the second portion of the first FMCW ultrasonic signal, the second energy value being associated with a second distance;
calculating an average distance using the first distance and the second distance; and
determining, based at least in part on the average distance, distance data indicating a distance between the object and the monitoring device.