US 11,724,787 B2
Methods and systems for determining a depth of an object
Thomas E. Wood, Portsmouth, RI (US); and John R. Short, Portsmouth, RI (US)
Assigned to Raytheon Company, Waltham, MA (US)
Filed by Raytheon Company, Waltham, MA (US)
Filed on Aug. 7, 2019, as Appl. No. 16/534,038.
Prior Publication US 2021/0039762 A1, Feb. 11, 2021
Int. Cl. B63G 8/08 (2006.01); B63G 7/08 (2006.01); B63G 8/00 (2006.01); G01S 5/02 (2010.01); G01S 15/89 (2006.01); G05D 1/06 (2006.01); B63G 7/00 (2006.01)
CPC B63G 8/08 (2013.01) [B63G 7/08 (2013.01); B63G 8/001 (2013.01); G01S 5/0294 (2013.01); G01S 15/8981 (2013.01); G05D 1/0692 (2013.01); B63G 2007/005 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method comprising:
providing an autonomous vehicle (AV) with a first estimated position of a target;
directing the AV to travel toward the first estimated position at a constant velocity;
receiving, from a 2-dimensional sensor of the AV, echo signals of transmitted sonar signals, the echo signals indicating a range and an azimuth of the target;
measuring range of the target over time using from the echo signals;
for each of a plurality of candidate depth differences, generating data corresponding to a change in range of the target over time that would be expected if the AV and the target had the candidate depth difference;
determining a depth difference of the AV and the target as the one of the plurality of candidate depth differences for which the generated data has a best fit to the measured change in range of the target over time; and
in response to a depth difference existing:
determining a direction of the depth difference, the direction indicating whether the target is above or below the AV, and
re-directing the AV toward a second estimated position of the target generated from the depth difference and the direction of the depth difference.