Single-Frequency PPP-RTK: Theory and Experimental Results Dennis Odijk, Peter J.G. Teunissen, and Amir Khodabandeh Abstract Integer ambiguity resolution enabled Precise (cm-level) Point Positioning (PPP) is feasible if corrections from a GPS network of CORS stations are applied to the single-receiver phase and code data of a user. The concept of PPP-RTK requires a proper definition and quality of the PPP-user network corrections, which are satellite clocks, satellite phase biases and ionospheric delays interpolated to the approximate location of the user. The availability of the satellite phase bias corrections enables the user to carry out integer resolution of ambiguities that are double-differenced, i.e., relative to those of the pivot receiver in the network. The availability of the interpolated ionospheric corrections is not absolutely required, however PPP-RTK for single-frequency users would virtually be impossible without them. A proper handling of the network corrections implies that the PPP-user should take their uncertainty into account as well. In order to limit the amount of information to be transmitted to the user, in this contribution we provide a closed-form analytical expression for the variance matrix of the network corrections which a single- frequency user can apply in his processing. Experimental results of single-frequency PPP- RTK for both a high-grade geodetic receiver as well as a low-grade mass-market receiver demonstrate that although single-epoch integer ambiguity resolution is not possible, single- frequency ambiguity resolution enabled cm-level PPP is feasible based on an accumulation of less than 10 min of observations plus network corrections on average. Keywords GPS • PPP-RTK • Single frequency • Integer ambiguity resolution • Closed-form variance matrix 1 Introduction The technique of Precise Point Positioning (PPP) is based on GPS carrier phase and code (pseudo-range) observations of a single receiver, employing corrections for, among others, satellite orbits, clocks and ionospheric delays obtained from a worldwide network of GPS stations, for example the permanent GPS network of the International GNSS Service D. Odijk () • P.J.G. Teunissen • A. Khodabandeh Curtin University, GPO Box U1987, Perth, WA 6845, Australia e-mail: d.odijk@curtin.edu.au (IGS; Dow et al. (2009)). PPP was introduced in Zumberge et al. (1997) and the attainable instantaneous precision for a single-frequency user who employs global corrections is typically at the level of a few dm (van Bree and Tiberius 2012; Huisman et al. 2012). The key to fast and cm-level PPP lies in resolving the ambiguities that are present in the phase data to integer values. Unfortunately, with the standard PPP technique this is not possible, because the ambiguities cannot be separated from the satellite hardware biases in the phase and code data. In this contribution we will present an approach that allows the single-receiver user to perform integer ambiguity resolution within short time spans and consequently enable C. Rizos and P. Willis (eds.), Earth on the Edge: Science for a Sustainable Planet, International Association of Geodesy Symposia 139, DOI 10.1007/978-3-642-37222-3__75, © Springer-Verlag Berlin Heidelberg 2014 571