US 12,355,555 B2
Ranging between unsynchronized communication terminals
P. Stephan Bedrosian, McLean, VA (US)
Assigned to MITRE Corporation, McLean, VA (US)
Filed by MITRE Corporation, McLean, VA (US)
Filed on Jan. 24, 2024, as Appl. No. 18/421,093.
Application 18/421,093 is a continuation of application No. 17/538,146, filed on Nov. 30, 2021, granted, now 11,902,016.
Prior Publication US 2024/0162999 A1, May 16, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H04W 56/00 (2009.01); H04J 3/06 (2006.01); H04L 43/0864 (2022.01)
CPC H04J 3/0661 (2013.01) [H04L 43/0864 (2013.01); H04W 56/0065 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for determining a range between two unsynchronized communications terminals in motion comprising:
transmitting, by a first terminal, a range request to a second terminal;
storing, by the first terminal, a first timestamp in memory corresponding to a time at which the range request message was transmitted;
receiving, by the first terminal from the second terminal, a range response to the range request, the range response including a residence time that characterizes an amount of time the second terminal required to send the range response after receiving the range request;
storing, by the first terminal, a second timestamp in memory corresponding to a time at which the range response was received;
calculating a roundtrip time for the range request and range response based on the second timestamp minus the first timestamp and the residence time; and
calculating a distance between the first terminal and the second terminal based on the roundtrip time and adjusted for relative motion between the terminals.