There are a few limitations with RTK correction extension services. Any obstructions (i.e., grain tanks, tree lines, etc) that can degrade or block the L-Band satellite signals will affect performance. An L-Band signal block will cause the position error to increase over time. If L-Band signals are lost for more than 2 minutes during the RTK extension period, then RTK-level accuracies cannot be maintained and the correction extension service will end.
It’s also worth noting that accuracy degrades the longer the RTK correction outage period, but it will level out at approximately 4-5 cm. That’s because providers like NovAtel rely on global Precise Point Positioning (PPP) correction data to extend the RTK positioning solution during the outages. While global PPP data provides a consistent solution to all users regardless of location, it has the disadvantage of not containing the local correction information that enables a true RTK solution. Also, if the RTK outage occurs in the first 30 minutes of receiver operation, further degradation to approximately 20 cm may be observed while operating with an RTK extension service.
RTK is the accepted solution in many applications that require instant, centimetre-level positioning. Applications ranging from agriculture to survey & mapping, to unmanned vehicles and more all depend on RTK to some degree. RTK correction
extension services extend RTK operation for any of these applications, which improves productivity by reducing the downtime caused by RTK correction signal outages. As long as RTK positioning has commenced prior to the outage, a correction extension service can help maintain continuous operation and ensure maximum productivity.