Knowledge base GNSS/RTK
- FKP - A network based solution with of code and carrier using a system of gradient messages to describe the overall corrections environment (rather then corrections develop and suited to a unique position). It is in contrast to the MAC approach and has its own message types defined in RTCM.
- iMAX (Individualized Master Auxiliary Correction) - A feature of the Leica network that uses a real reference station as the source of the network corrections, so there is consistency and traceability of the corrections received by GNSS rover.
- MAC - A network based solution with of code and carrier using "Master – Auxiliary" methods (and messages) as defined in RTCM.
- NEAREST - Automatic detection of the nearest base station and connection to it. Work from one base station. Also called a single baseline solution.
- NET - Averages the position from the closest 3 base stations.
- NRTK - Network RTK, a general term which can be applied to any of the terms / methods found here. As MAC and FKP methodologies have fallen out of favor, more and more solutions simply use single baseline approaches or create synthetic observations (using either legacy messages or MSM messages). NRTK is now the preferred term used for all of these.
- VRS - Virtual Reference Station. Averages the position from the closest 3 base stations and creates a virtual base somewhere on the site.
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PPP is a signal enhancement method that eliminates GNSS errors to ensure high positioning accuracy using only a single receiver. PPP solutions rely on GNSS satellite clock and orbital corrections, which are transmitted on separate frequencies from the satellites, enabling decimeter-level or better real-time positioning without using ground infrastructure. PPP solutions typically require a convergence period of 5-30 minutes to resolve any local distortions, such as atmospheric conditions, multipath, and satellite geometry.
- RTCM (Radio Technical Commission for Maritime Services) - Open source correction format to send accurate position information.
- RTCM 2.3 - GPS only.
- RTCM 3.1 - GPS + GLONASS
- RTCM 3.2 - GPS (L1, L2, L5) + GLONASS + Galileo + BDS
- MSM (Multiple Signal Messages) - More messages sent with the RTCM 3.2 correction format.
- CMR - A Trimble-specific correction format. CMR and CMR+ are open to public use. CMR only supports GPS. CMR+ supports GPS + GLONASS.