Selection of the appropriate augmentation method or correction service depends on the performance required for each application. There are essentially four levels of positioning: standalone uncorrected; positioning derived from publicly available correction services such as the WAAS network in North America or Europe’s EGNOS system; positioning solutions derived from globally available subscription-based L-band services; and regional/ local RTK network solutions.
Standalone uncorrected and WAAS/EGNOS type solutions provide accuracies ranging from 1-10 metres. On the other end of the scale, RTK correction networks provide the most accurate centimetre-level solutions. While L-band solutions deliver corrections directly to the GNSS receiver via satellite, RTK solutions require a base station and a radio to get the corrections needed, limiting operator flexibility and increasing total system cost and complexity.
With subscription-based L-band correction services, users receive Precise Point Positioning (PPP) corrections to help mitigate and remove measurement errors and position jumps. PPP solutions utilize modeling and correction products including precise satellite clock and orbit data to enhance accuracy. Such services range in price from $300 to $4,000 per year, depending on the desired accuracy, end user application and subscription duration.