4 ms·
Survey-grade GPS (using CORS and WAAS correction) using RTK will give you accuracy to ~10 cm within a few seconds. You can get that down to several millimetres
by urschrei 7y ago
Survey-grade GPS (using CORS and WAAS correction) using RTK will give you accuracy to ~10 cm within a few seconds. You can get that down to several millimetres if you can tolerate post-processing several hours worth of static data.
- ISL 7y agoIs accuracy at that level actually possible with GPS? Precision seems likely, but it is substantially more difficult to provide absolute accuracy at that level.
- urschrei 7y agoI'm by no means an expert, but yes, if you can use a modern realisation (e.g. ITRF2014) and have access to VLBI / DORIS / GNSS then sub-centimetre accuracy is possible, though not in real time.
- scblock 7y agoYes, but not on its own, that I am aware. High accuracy GPS is is based on a combination of GPS satellite data itself with real time or post-processed positional correction using references stations which themselves are placed in a known surveyed location. In the US, 60 cm accuracy is often possible with nothing more than WAAS corrections. 10 or even 1 cm accuracy is often possible in real time with access to an RTK network.
- OliverJones 7y agoIt's true. But survey-grade coordinates generally are used in a universal transverse Mercator, or in some locales a Lambert conic or some other locally useful projection. Those projections take into account such things as the deviation of the earth's shape from a perfect sphere. Rule about lat/long precision: If somebody says the words "datum" or "projection" to you, and you say "huh?", then you only need four digits after the decimal point in your lat/long coordinates. On the other hand, if you're designing an outdoor parking lot and you don't want puddles, please use survey-grade coordinates.