Network RTK

Network RTK requires a recommended minimum of five reference stations (there is no maximum) with an inter-station spacing of up to 70 km.

The reference stations are usually permanent installations and form the RTK Network , which is the backbone of the Network RTK principle.

The Principle

The principle of Network RTK begins with all reference stations within the RTK Network continuously streaming satellite observations to a central server running Network RTK software, such as Leica GNSS Spider.

The aim of Network RTK is to minimise the influence of the distance dependant errors on the rovers computed position within the bounds of the network. The Network RTK server software begins this process by:

  1. Fixing the ambiguities of the satellites (being observed by the reference stations) within the network; and
  2. Using the data from all (or a subset of) reference stations to generate corrections that are sent out to the rover (Fig. 3).

 

Figure 3: Principle of Network RTK

 Figure 3: Principle of Network RTK

 

Advantages Disadvantages

The advantages of Network RTK are:

  • No need to set up a base station.
  • The accuracies of the computed rover position are more homogeneous.
  • The accuracy is maintained over larger distances between the reference stations and the rover.
  • The same area can be covered with fewer reference stations (i.e. compared to the number of permanent stations required using Single Reference RTK).
  • Higher reliability and availability of RTK corrections (e.g. one station goes down, another station can take over)

The disavantage of Network RTK  is:

  • The cost to subscribe to an RTK Network and receive Network RTK corrections.

This decrease in accuracy is due to distance dependant errors - mainly atmospheric errors. Essentially, as the distance between the rover and the reference station increases, the atmospheric conditions at the rover and reference station will become increasingly different. This decreases the accuracy and makes it more difficult for the rover to fix the ambiguities.