US 11,927,923 B2
Time synchronization system, management device, time synchronization method, and program
Takaaki Hisashima, Tokyo (JP); Hiroki Sakuma, Tokyo (JP); Kaoru Arai, Tokyo (JP); Ryuta Sugiyama, Tokyo (JP); Shunichi Tsuboi, Tokyo (JP); Osamu Kurokawa, Tokyo (JP); and Kazuyuki Matsumura, Tokyo (JP)
Assigned to Nippon Telegraph and Telephone Corporation, Tokyo (JP)
Appl. No. 16/977,988
Filed by Nippon Telegraph and Telephone Corporation, Tokyo (JP)
PCT Filed Mar. 5, 2019, PCT No. PCT/JP2019/008711
§ 371(c)(1), (2) Date Sep. 3, 2020,
PCT Pub. No. WO2019/176660, PCT Pub. Date Sep. 19, 2019.
Claims priority of application No. 2018-045224 (JP), filed on Mar. 13, 2018.
Prior Publication US 2021/0072707 A1, Mar. 11, 2021
Int. Cl. G04R 20/02 (2013.01); G01S 19/21 (2010.01); G01S 19/25 (2010.01); G04G 5/00 (2013.01); G04G 7/00 (2006.01)
CPC G04R 20/02 (2013.01) [G01S 19/21 (2013.01); G01S 19/256 (2013.01); G04G 5/002 (2013.01); G04G 7/023 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A time synchronization system comprising:
a plurality of time synchronization apparatuses, each of the plurality of time synchronization apparatuses configured to receive a radio wave from a positioning satellite and to take time synchronization using time information included in the received radio wave as a time source to deliver a time; and
a management apparatus including one or more processors configured to:
acquire time variation information and position information of each of the time synchronization apparatuses;
classify the time synchronization apparatuses into predetermined categories based on the acquired position information;
determine a first subset of time synchronization apparatuses of the plurality of time synchronization apparatuses based on whether patterns of the time variation information of each time synchronization apparatuses belonging to an identical category are identical to each other;
analyze the time variation information from the first subset of time synchronization apparatuses; and
an output unit configured to output an instruction to block the time variation information received from the positioning satellite to the time synchronization apparatus having abnormal time variation,
wherein each time synchronization apparatus of the plurality of time synchronization apparatuses is configured to, in a case of receiving a block instruction from the management apparatus, block the time information received from the positioning satellite.