US 12,010,586 B2
Position estimation method, position estimation system, position estimation server, and position estimation program
Masamichi Hosoda, Musashino (JP); Tadashi Mori, Musashino (JP); Masaru Miyamoto, Musashino (JP); Hiroshi Sakamoto, Musashino (JP); Tomoki Murakami, Musashino (JP); and Tomoaki Ogawa, Musashino (JP)
Assigned to NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo (JP)
Appl. No. 17/428,270
Filed by NIPPON TELEGRAPH AND TELEPHONE CORPORATION, Tokyo (JP)
PCT Filed Jan. 27, 2020, PCT No. PCT/JP2020/002753
§ 371(c)(1), (2) Date Aug. 3, 2021,
PCT Pub. No. WO2020/162251, PCT Pub. Date Aug. 13, 2020.
Claims priority of application No. 2019-020139 (JP), filed on Feb. 6, 2019.
Prior Publication US 2022/0109955 A1, Apr. 7, 2022
Int. Cl. H04W 4/029 (2018.01); G01S 13/87 (2006.01); H04B 17/318 (2015.01); H04L 43/0864 (2022.01)
CPC H04W 4/029 (2018.02) [G01S 13/876 (2013.01); H04B 17/318 (2015.01); H04L 43/0864 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A position estimation method comprising:
transmitting a measurement signal and receiving a response signal between multiple n wireless stations respectively provided with known antennas i (i=1, 2, . . . , n) installed at known positions different from each other and a wireless terminal station provided with a terminal antenna installed at an unknown position;
measuring RTT, which is a round-trip delay time of the transmission and the reception;
obtaining coordinate information of an estimated position of the wireless terminal station with the terminal antenna in response to the measured RTT by the known antennas i;
applying the coordinate information to an RTT evaluation function fti to evaluate the estimated position of the wireless terminal station with the terminal antenna, the RTT evaluation function fti having terms relating to the coordinate information, a value of each of the terms being variable;
determine, by using a range evaluation function k, whether the value of each of the terms of the RTT evaluation function fti is within an acceptable range in which the wireless terminal station with the terminal antenna is to be present, the range evaluation function fL having the terms;
setting a value of each of the terms of the range evaluation function fL to zero when the value of each of the terms of the RTT evaluation function fti is within the acceptable range;
setting the value of each of the terms of the range evaluation function fL to a proportional value when the value of each of the terms of the RTT evaluation function fti deviates from the acceptable range by a deviation amount, the proportional value being larger as the deviation amount becomes larger; and
estimating a position of the wireless terminal station with the terminal antenna based on either:
a solution of simultaneous equations of the RTT evaluation function fti and the range evaluation function fL; or
a value obtained by searching for an estimate value in a case in which an error evaluation function ferror obtained by combining the RTT evaluation function fti and the range evaluation function fL is minimum.