Hi Michael,
Let me clarify this.
Reach RS+ is a single-band receiver. It’s capable of obtaining centimeter-level accuracy if you’re using it in RTK and PPK. This ultimately implies that another receiver is necessary whether it’s a remote NTRIP station or the local base station.
If you don’t need absolute centimeter-level accuracy for your survey, you can set up your Reach RS+ receiver as a base on an unknown point by averaging the position in a Single solution. The absolute accuracy of the position you’re going to get is about a few meters. If you set up a multi-band Reach RS2 in a standalone mode, you will get the same accuracy of a few meters.
If you need to establish a coordinate of an unknown point with absolute centimeter-level accuracy in an area without Internet access, you can use the PPP services as other users have mentioned. We have a detailed guide on it.
The majority of the services do in fact work with multi-frequency logs to have more data for analysis. With a single-band receiver, you can work with NRCAN service. It’s possible to get the accuracy of up to 15-30 cm with it as our user’s test suggests.
Let me repeat that Reach RS+ and Reach RS2 are capable of obtaining the same centimeter-level accuracy while working in RTK and PPK. These receivers are designed to be used in different conditions. Reach RS2, as a multi-band receiver, allows you to survey in somewhat complicated environments like urban areas or under light foliage. You can also reach longer baselines and obtain Fix in RTK faster.
Reach RS+ can be used in an open area with a clear sky view and in RTK it usually takes a couple of minutes to achieve a Fix solution. These are the characteristics and requirements for any single-band receiver.
It’s up to you to assess your environment and requirements of your workflow to decide which of the receivers is more suitable for you. For surveying in a somewhat difficult environment, it might be a good idea to consider Reach RS2.
I’d also suggest taking a look at our Placing the base guide where we described the most common scenarios of placing local base station with our receivers.
I hope this clears up the topic a bit.