US 12,228,664 B2
Locating a transmitter by means of a plurality of geographically remote receiving stations using known object paths
Baptiste Guillot, Moissy Cramayel (FR); and Yann Picard, Moissy Cramayel (FR)
Assigned to SAFRAN DATA SYSTEMS, Courtaboeuf (FR)
Appl. No. 17/788,973
Filed by SAFRAN DATA SYSTEMS, Courtaboeuf (FR)
PCT Filed Dec. 24, 2020, PCT No. PCT/FR2020/052625
§ 371(c)(1), (2) Date Jun. 24, 2022,
PCT Pub. No. WO2021/130463, PCT Pub. Date Jul. 1, 2021.
Claims priority of application No. 1915619 (FR), filed on Dec. 26, 2019.
Prior Publication US 2023/0037150 A1, Feb. 2, 2023
Int. Cl. H04W 24/00 (2009.01); G01S 5/02 (2010.01); G01S 5/06 (2006.01)
CPC G01S 5/02216 (2020.05) [G01S 5/0246 (2020.05); G01S 5/06 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method for locating a transmitter, implemented in a processing unit of a processing station of a locating system comprising the following steps:
receiving signals acquired by geographically remote receiving stations, said signals being dated by local time bases of each receiving station and corresponding to signals from a transmitter to be located and from at least one known object;
determining, on the basis of the dated signals, the measured TDOAs relating to the transmitter to be located and to the object; and/or measured FDOAs relating to the transmitter to be located and to the known object;
determining, on the basis of known ephemerides relating to the known object and of geographical positions of the stations; theoretical TDOAs relating to the known object; and/or theoretical FDOAs;
determining, by taking the difference of the measured and theoretical TDOAs and/or FDOAs relating to the known object, a residual error affecting the measured TDOAs and/or FDOAs in such a way that each receiving station corrects its local clock or the processing station corrects the timestamps of the portions of the signals from each receiving station;
determining the location of the transmitter using measured TDOAs and/or FDOAs once the receiving stations have corrected their local time base or the processing station has corrected the timestamps of the portions of the signals from each receiving station; and
determining, on the basis of the measured TDOAs and/or FDOAs relating to several objects, an indicator of reliability of said measured time-domain or frequency-domain separations, said reliability indicator making it possible to determine whether or not the ephemerides of the known object can be used for the correction of the local clock and for, in particular, determining whether or not the known object is in the process of maneuvering.