2021 Short Course: Multi-GNSS PPP

2021 Short Course: Multi-GNSS Precise Point Positioning and PRIDE PPP-AR

Dates: September 7 and 9, 2021
Times:  5:30 – 8:00 MDT (11:30 – 14:00 UTC).
Venue: This short course is offered in a virtual format only.

Learning Goals: Participants who complete this course will gain an understanding of the theory of Global Navigation Satellite System (GNSS) precise point positioning (PPP), undifferenced ambiguity resolution, phase and code biases, multi-GNSS (GPS/GLONASS/BDS/Galileo/QZSS) integration, satellite attitude corrections, troposphere retrieval, higher-order ionosphere corrections, and super-high-rate (50 Hz) data processing. The participants will also learn how to use the PRIDE PPP-AR software to accomplish PPP and PPP ambiguity resolution at static and kinematic stations for tectonics, seismology, aerial photogrammetry, and airborne/shipborne gravimetry.

Course Description. Precise Point Positioning using GNSS measurements is recognized as a valuable tool in a number of meteorological and geophysical applications. The success of this technique can be attributed to its advantages over the more conventional relative positioning techniques, including its ease of use and the lack of the requirement for any reference stations, whilst still giving comparable positioning precisions. In addition to this flexibility and cost-effectiveness, PPP has the capability of providing services of homogeneous accuracy on a global scale in both the post-processing mode and the real-time mode.

Unlike double-difference GNSS data processing, undifferenced ambiguities in PPP cannot be fixed to integers, which has been prohibiting the further accuracy improvement of position estimates, especially within short observation periods such as a few hours. The main barrier that prevents PPP ambiguity resolution is the existence of non-zero and non-integer phase biases originating in the receivers and satellites. They can hardly be separated from the integer ambiguities in a least-squares adjustment. PPP ambiguities are constantly recognized as realvalued parameters in the published literature. Consequently, integer ambiguity resolution in PPP was considered impossible by many researchers.

This course will introduce fundamentals of PPP and multi-GNSS integration for undifferenced data processing with a focus on what corrections should be applied to ensure that PPP can achieve millimeter precision in daily GNSS and centimeter precision in kinematic GNSS. Undifferenced multi-GNSS ambiguity resolution will be introduced in detail and experimented with PRIDE PPP-AR software.

Application Process. Interested individuals should apply to participate. Applications will be reviewed and acceptance decisions will be based on responses to prompts in the application. Initial priority of applications will be given to post-doctoral associates and graduate students from UNAVCO member institutions. (Check to see if your institution is a member of the UNAVCO consortium.) Review of applications begins June 22, 2021; applicants will be notified of their application status beginning July 1, 2021.

General participation in this course does not require a fee.

Brief Agenda

Fundamentals of PPP (IGS orbits and clocks)
Atmosphere corrections in PPP
Multi-GNSS integration (clock steering, satellite attitudes)
PPP for mobile stations (airplanes, ships, seismic stations)
Undifferenced ambiguity resolution (code and phase biases)

Prerequisite, Computers, and Data

The participants should have fundamental knowledge of GNSS theories and applications. Participants should have access to have a Linux/Mac and GFortran compiler.


Jianghui Geng, Professor in GNSS geodesy at Wuhan University, High-precision GNSS

Charlie Sievers, UNAVCO


Please contact Melissa Weber, weberat symbolunavco.org, or Jianghui Geng, jgengat symbolwhu.edu.cn