Got a reply from Point One Nav:
Unfortunately there is no perfect answer to questions like this. RTK positioning is driven in large part by the quality of the user's device and the environment where a device is working. We have users who get sub 4cm level accuracy out to 75km. We also have had users that report challenges within a few km of our perfectly functional base stations. After researching those experiences with the users, they are generally attempting to get a fix with an obstructed skyview (many of them indoors), they have a large
multi-path source immediately adjacent to the test area, or they have some kind of hardware or firmware problem preventing their device from working as well as they hoped it would.
Typically, the three biggest determining factors (in no particular order) of the quality of the position are:
- The quality, as well as the constellation and signal support of the GPS antenna and receiver in use.
- The distance from the source of the corrections. Yes, this is absolutely a factor and the closer you are to the center of those circles the faster your device will be able to get a fix and the more likely the solver will be able to maintain that fix. But I wouldn't want to quote a specific number for you given the amount of GPS hardware variability in the world today.
- The quality of the cellular service at the location you are working in. Because you need to source the corrections from our servers, if you are working in an environment that has limited cellular bandwidth or a cellular network that has a high latency (> 1s) your device could have trouble maintaining a connection to the data stream. When this happens the device can lose its "fixed" status and the calculated position can drift.
The experience a particular user has with their equipment generally comes down to the sum of those 3 factors. At a high level, the user will have the best quality solution within those more opaque blue circles with the quality and performance getting better as you get closer to the middle of the circle. We have many users that have very good results out to 60 and 70+km. We also have regular reports of high quality corrections even past that if the test site has high marks for the above data points.
The best recommendation I can give anyone is to give Polaris a try; maximize that 2 week trial and let us know if you are experiencing problems. We will do our best to help get answers to questions as quickly as we can. They can sign up for an account to check our coverage map. If they are working within one of those more opaque blue circles on that coverage map then there is a good chance they can use our solution. It is our hope that everyone's experience with Polaris matches their requirements. We are also constantly expanding our network so stay tuned to our map and our
online news feed to learn what we are up to as we continue to bring the easiest to use high-precision positioning possible to our users.