US 12,222,434 B2
Node positioning
Jukka Kämäräinen, Vuokatti (FI); and Pertti Erkkilä, Vuokatti (FI)
Assigned to Iiwari Tracking Solutions Oy, Vuokatti (FI)
Filed by Iiwari Tracking Solutions Oy, Vuokatti (FI)
Filed on Jun. 23, 2022, as Appl. No. 17/847,176.
Claims priority of application No. 20215753 (FI), filed on Jun. 24, 2021.
Prior Publication US 2022/0413085 A1, Dec. 29, 2022
Int. Cl. G01S 5/10 (2006.01); G01S 5/02 (2010.01); G01S 5/06 (2006.01)
CPC G01S 5/10 (2013.01) [G01S 5/02216 (2020.05); G01S 5/06 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method comprising:
obtaining a first length of time, limited by receipt of a second message in a first non-master base station and by receipt of a signal from a wireless tag in the first non-master base station, obtaining a second length of time, limited by receipt of the second message in the first non-master base station and by receipt of a first message in the first non-master base station;
obtaining a third length of time, limited by receipt of the second message in a second non-master base station and by receipt of the signal from the wireless tag in the second non-master base station, obtaining a fourth length of time, limited by receipt of the second message in the second non-master base station and by receipt of the first message in the second non-master base station and obtaining a fifth length of time, limited by a time of transmission of the first message from a master base station and a time of transmission of the second message, of a same type as the first message, from the master base station, and
determining a time difference of arrival of the signal from the wireless tag between the first and second non-master base stations as the third length of time multiplied by a ratio of the fifth length of time and the fourth length of time, to which is added a time of flight at light speed from the master base station to the second non-master base station and from which is subtracted a product of the first length of time and a ratio of the fifth length of time and the second length of time, and from which is subtracted a time of flight at light speed from the master base station to the first non-master base station.