Seoul National University

Cdnetworks Co., Ltd.

O Jong Kim

Jungbeom Kim

Chang Don Kee

Seung Young Kim

Yonghwan Bae

Weon Gyo Jeong

Kyung Min Roh

Junesol Song

A method for estimating a multipath error of a pseudo-range measurement value, comprising obtaining satellite navigation system information including a pseudo-range measurement value and a carrier phase measurement value; obtaining a time-differenced carrier phase (TDCP) measurement value by differentiating the carrier phase measurement value with respect to time; setting a monitoring variable for multipath error estimation by using the TDCP measurement value; detecting a change in multipath error using the monitoring variable, and determining a time period usable to estimate the multipath error; and estimating the multipath error at a specific time point using the change relative to a reference time. Accordingly, the location of a target can be precisely determined even in a downtown environment with severe signal distortion, by estimating the multipath error included in the pseudo-range measurement value, and compensating for or excluding the multipath error.

Method for estimating multipath error of pseudo-range measurement value, and positioning method using same

A time-differenced carrier phase (TDCP) measurement value-based navigation system according to one embodiment of the present disclosure comprises: a satellite navigation system information reception unit for acquiring satellite navigation system information including a carrier phase measurement value; an initial position determination unit for determining an initial position of a target on the basis of the satellite navigation system information; a TDCP acquisition unit for acquiring a TDCP measurement value; a relative position determination unit for determining a relative position of the target on the basis of the TDCP measurement value; and an absolute position determination unit for determining an absolute position of the target by accumulating relative positions according to time of the initial position of the target. Therefore, time and expenses required for determining integer ambiguity can be reduced, and precise position of a cm-level error can be measured by using a low-cost satellite navigation system information receiver.

Time-differenced carrier phase measurement value-based navigation system, and position measurement method

The present invention relates to a file system, an apparatus in the file system thereof, and a method of providing and managing content in the file system thereof. According to the present invention, it may be possible to minimize data loss caused by server failure and to provide the convenience of data (content) management by (1) grouping overall data nodes (servers) to manage with a network server group including several data nodes (servers), (2) defining content management information, (3) storing and duplicating contents in each network server group using the defined content management information to maintain and manage the contents, (4) and maintaining and managing the contents in a file unit without using file chunks.

File system and method for delivering contents in file system

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Seoul, South Korea

O Jong Kim