RT-PPP - Development of a Real-time PPP Processing Facility

The overall goal of the RT-PPP project, was to develop PPP techniques suitable for various real-time or near real-time applications. The main focus was placed on the production of real-time clock, orbit and atmospheric corrections as well as their transmission via Ntrip to a user client.

Short Description

A variety of applications currently lacks a cheap though relatively precise positioning device and could highly profit from a real- time Precise Point Positioning (PPP) processing facility. PPP denotes a positioning technique where code and phase measure- ments from a single GNSS (Global Navigation Satellite System) receiver are used to produce precise positions using globally valid precise orbit and clock corrections provided e.g. by the Inter- national GNSS Service (IGS). Typically, an ionosphere-free linear combination is used to eliminate the ionospheric delay. Other error terms like tropospheric delay or receiver clock biases can be estimated.

Formerly the PPP technique was mainly used for post-processing due to long convergence times and a lack of precise real-time products. In the last years, however, the demand for real-time positioning with PPP has arisen together with a handful of services. Nevertheless, real-time PPP is only in the starting phase and only few applications make use of the technique.

There are still many unsolved problems like the prevention of float ambiguities during PPP processing and the insufficient availability of real-time correction data directly affecting position accuracy. These problems were addressed by the RT-PPP project. 

The options for applying integrity monitoring algorithms to PPP were also investigated. The presented approaches as well as a facility to enable reception of real-time corrections were implemented into a user module.

Extensive testing was carried out to assess the performance of the developed real-time PPP processing facility in terms of quality, integrity and availability. The project also involved assessing the suitability for real-time applications such as positioning of snow removal machines or navigation of agricultural vehicles.

Project Partners


Graz University of Technology, Institute of Navigation - Katrin Huber


  • Vienna University of Technology, Institute of Geodesy and Geophysics - Robert Weber
  • TeleConsult Austria GmbH - Markus Troger
  • WIEN ENERGIE Stromnetz GmbH - Christian Klug

Contact Address

Graz University of Technology - Institute of Navigation
Katrin Huber
Steyrergasse 30
A-8010 Graz
Tel.: +43 (316) 873 - 6832
E-mail: katrin.huber@tugraz.at
Web: www.inas.tugraz.at