GNSS positioning uses signals coming from space and Trimble Catalyst has to be used outdoors. High-accuracy GNSS systems like Catalyst use a technology called differential corrections to correct position errors in real-time while you work, so there must also be a way for the Catalyst receiver to access this correction data in the field. All Catalyst subscriptions include free access to both Trimble VRS Now and Trimble RTX correction services via the Trimble Corrections Hub (TCH). These Trimble correction services can be delivered via satellite (RTX only) or via a mobile internet connection (both RTX and VRS Now). Catalyst also allows the use of custom local correction services via mobile internet. Using cellular data or data roaming may incur additional charges from your cellular service provider. Check regional Trimble VRSNow and Trimble RTX coverage areas, or talk to your local Trimble distributor about local GNSS corrections options in your region.
Yes. An internet connection is required to download the Catalyst license file for your subscription before using the service for the first time, but once you have a license Catalyst can be used offline for up to 30 days, or until your license expires, whichever comes first. If you are using the Catalyst On Demand service, you need to be online to draw down and start a session on your device.
Catalyst GNSS performance is typically faster to converge in online conditions where corrections can be delivered over the internet connection of the connected phone or tablet with a higher bandwidth data connection than when using satellite-delivered corrections. In offline conditions, Catalyst will use corrections from the Trimble RTX service via satellite broadcast. Satellite broadcast RTX also requires line-of-site between the RTX satellite and the Catalyst antenna.
The way I explain this to my customers is that DA2 is just low cost Digital antenna. The subscription fee enables that antenna to provide the accuracy that the customer paid or subscribed for. You're not paying for the real-time accuracy. You are paying to have it activated to use either through Trimble Corrections or another NTRIP source. I like also to explain that just like a backpacker buys an emergency inReach device for $350 dollars. It requires some form of subscription for it to work. Hope that helps explain the technology.