Two-line element set: Difference between revisions

Revision as of 11:07, 7 November 2023

Revision as of 03:54, 10 November 2023

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The checksums for each line are calculated by adding all numerical digits on that line, including the line number. One is added to the checksum for each negative sign (-) on that line. All other non-digit characters are ignored.

For a body in a typical [[low Earth orbit]], the accuracy that can be obtained with the SGP4 orbit model is on the order of 1&nbsp;km within a few days of the epoch of the element set.<ref>{{cite web|author=Kelso, T.S.|title=Validation of SGP4 and IS-GPS-200D Against GPS Precision Ephemerides|quote=AAS paper 07-127, presented at the 17th AAS/AIAA Space Flight Mechanics Conference, Sedona, Arizona|date=29 January 2007|url=http://celestrak.com/publications/AAS/07-127/|publisher=Celestrak.com|access-date=28 November 2014}}</ref> The term "low orbit" may refer to either the altitude (minimal or global) or orbital period of the body. Historically, the SGP algorithms defines low orbit as an orbit of less- than 225 minutes.

Two-digit Epoch Years from 57 to 99 correspond to 1957-1999 and those from 00 to 56 correspond to 2000–2056.<ref>{{cite web |title=Frequently Asked Questions: Two-Line Element Set Format |publisher=CelesTrak |url=https://celestrak.com/columns/v04n03/}}</ref>