Discussion Overview
The discussion revolves around the epoch time for the WGS84 coordinate system, particularly in relation to GPS time and its synchronization with UTC. Participants explore the definitions and implications of epoch time in the context of coordinate systems and GPS technology.
Discussion Character
- Exploratory
- Technical explanation
- Debate/contested
Main Points Raised
- One participant inquires about the specific epoch time for the WGS84 coordinate system, noting that their GPS indicates a date of 06/01/1980.
- Another participant states that there isn't a precise epoch for the WGS84 coordinate system, suggesting that the year 1984 marks when the data was agreed upon, rather than a defined starting point.
- Some participants mention that while GPS time was synchronized with UTC in 1980, GPS time does not account for leap seconds, leading to a current lag.
- One participant highlights the need for a definite epoch in astronomical coordinates due to the movement of star positions, contrasting this with the relatively minor changes in Earth's shape affecting WGS84.
- There is a note that most GPS receivers provide UTC time, and that leap seconds are communicated to satellites as part of their update data.
Areas of Agreement / Disagreement
Participants express differing views on the existence and definition of an epoch for the WGS84 coordinate system, with no consensus reached on whether it is arbitrary or defined. The discussion includes both agreement on the synchronization of GPS and UTC and acknowledgment of the complexities involved.
Contextual Notes
There are unresolved aspects regarding the implications of leap seconds on GPS time and the accuracy of measurements over time. The discussion also touches on the differences between astronomical and terrestrial coordinate systems.