PPP-RTK: Precise Point Positioning UsingState-Space Representation in RTK Networks

摘要

The concept of precise point positioning (PPP) is currentlyrnassociated with global networks. Precise orbit and clockrnsolutions are used to enable absolute positioning of a single receiver. However, it is restricted in ambiguityrnresolution, in convergence time and in accuracy. Precisernpoint positioning based on RTK networks (PPP-RTK) asrnpresented overcomes these limitations and givesrncentimeter-accuracy in a few seconds.rnThe primary task in RTK networks using the Geo++rnGNSMART software is the precise monitoring andrnrepresentation of all individual GNSS error componentsrnusing state-space modeling. The advantages of state-spacernmodeling are well known for PPP applications. It is muchrncloser to the physical error sources and can thus betterrnrepresent the error characteristics. It allows to betterrnseparate the various error sources to improve performancernand can lead to much less bandwidth for transmission.rnWith RTK networks based on GNSMART it is possible tornapply the PPP concept with high accuracy. Ambiguityrnresolution within the RTK network is mandatory andrnallows the precise modeling of the system state. Since therninteger nature of the carrier phase ambiguities isrnmaintained, all error components can be consistentlyrnmodeled and give full accuracy in an ambiguity fixingrnGNSS application.rnFor today's realtime applications, observations of arnreference station together with network derived parametersrnto describe distance dependent errors or a virtual referencernstation are transmitted to GNSS users in the field using thernRTCM standards. This can be termed as representation inrnobservation space (Observation Space Representation:rnOSR). In contrast to this, also the actual state-space data