"StarFire㢠global subscription service provides real-time accuracy typically better than 5cm (<2 inches). Its globally corrected signal is available virtually anywhere on the Earth's surface on land or sea, from 72å¼N to 72å¼S latitude."
The correction can come from either satellite or via internet.
The article says it works with L1 (30cm to 1.5m accuracy) and L1/L2 GNSS systems.
Has anyone here used Starfire subscription service?
Yes. I didn't know that the correction was available by Internet. That's cool. This type of positioning has its limitations. Getting sub-decimeter accuracy requires time, about 20 minutes. Once the position converges the receiver produces this accuracy until loss of fix, if that's the right term. Then you must converge again. It's similar to L1 kinematic surveying in this regard. Excellent for open skies, which makes it great for agriculture and marine applications. Regardless of convergence, you're almost always assured submeter in good conditions. At least within a minute or so of receiving the correction.
Is there any provision of reinitializing on a known point? I thought I remembered seeing that with Trimble's RTX service but maybe not. RTX is basically the same thing but it sounds like Starfire might have better coverage.
I don't recall. It seems like that may exist, but it's been a while since I've used it.
The convergence time applies to all of these high precision sbas services, as far as I know. Didn't want to imply that this was unique to Starfire.
What datum are these corrections broadcast in? Could be a user beware thing, 5cm relative to what? I am guessing NOT NAD83(2011)...
When Dave Doyle mentioned a few years ago that you would be able to get 20cm or better from your phone in real time he wasn't far off the mark, times are a changing, anybody will be able to make precise measurements, it will still take a surveyor (or somebody that understands the difference between precision and accuracy) to straighten it all out and provide an accurate location.
SHG
Shelby H. Griggs PLS, post: 336459, member: 335 wrote: What datum are these corrections broadcast in? Could be a user beware thing, 5cm relative to what? I am guessing NOT NAD83(2011)...
When Dave Doyle mentioned a few years ago that you would be able to get 20cm or better from your phone in real time he wasn't far off the mark, times are a changing, anybody will be able to make precise measurements, it will still take a surveyor (or somebody that understands the difference between precision and accuracy) to straighten it all out and provide an accurate location.
SHG
Glad you asked! ITRF08 usually. So yeah, you definitely want to address the transformation. NAD83 is 2 meters (3D) from ITRF, so it makes a difference.
Not sure about anyone else, but Trimble has the ITRF - NAD83(2011) transformation available in Access and TBC. To the extent that I've been able to test it it appears to be solid.
I haven't used any of the RT PPP stuff, BUT post process using PPP quite a bit for our airborne operations, works very well.
SHG
In rugged parts of the country, a man could reasonably do cadastral surveys, in my opinion, with the accuracy of these kinds of systems.
Realistically, how precisely do you need to locate those rock mounds? Heresy, I know, but I think it's legitimate. Those convergence times will get you, but I think on big country, it's not that big of an issue. Also, I don't think it is very robust in canopy, but again, in certain parts of the world, that's not really a problem either.