TopNET+ is Topcon's dedicated GNSS network correction service, available to all subscribers using a GNSS receiver unit and a mobile data connection. With this service, users can carry out their usual surveying activities without the need for a GNSS base station, as network corrections are supplied to the rover using a low cost GPRS connection, offering real time positioning in the coordinate system of your choice.

Note that we refer to it as a GNSS (Global Navigation Satellite System) rather than just GPS; thanks to the infrastructure of our partners in conjunction with our own network; we are able to provide both GPS & GLONASS corrections throughout Ireland.

Topcon were the pioneers of dual constellation GNSS survey equipment and techniques and have over nine years of experience working with this technology. Our customers have been used to the superior reliability and accuracy offered by dual constellation GNSS, as well as the improvements in working practices by always having extra satellites available to use.

Since 2008, we have been providing a subscription based DGNSS (Differential Global Navigations Satellite System) service through the United Kingdom and Ireland offering a dual constellation correction service for GIS / Mapping grade user. This system has enabled users to carry out mapping activities at a decimetre level of accuracy, using products such as our GMS-2 handheld GNSS receiver / controller.

From January 2010, we are very pleased to be able to offer users a new service providing a higher accuracy RTK grade level of working using the Ordnance Survey Ireland's and Land Property Services of Northern Ireland's nationwide CORS (Continuously Operating Reference Stations) network.

Topcon are now working in partnership with these organisations and using data from OSi and LPS, we can now offer users an RTK grade subscription service to allow positioning activities at centimetre level accuracy.

 The correction service works using an industry standard data transportation technique called NTRIP. This NTRIP (Network Transport of RTCM data by Internet Protocol) is a method whereby data corrections are transmitted using a standard internet based communication device. This could be a direct broadband cable or wireless connection, but typically for mobile users, a data-enabled mobile connection is used to transmit the corrections from the NTRIP server to the mobile device via a GPRS (General Packet Radio Service) connection.