2021 Short Course: GNSS Interferometric Reflectometry

Basic Principles and an Introduction to the gnssrefl Software Package

Dates: October 6 through 21, 2021, independent work with class meetings October 6 and 21.   
Times: Varies per day, see agenda below
Venue: This course will be offered virtually
Caveat: We may shift the start time (UTC) on October 6 and 21 depending upon enrollment.

The goals for this short course are to (1) introduce participants to the basic principles of the GNSS-IR method, (2) provide support for users installing and running gnssrefl (python, PyPi, Jupyter notebooks, Docker images, introduce use cases), and (3) demonstrate and discuss its use in two practical sessions on snow accumulation and water levels.

Participants successfully completing this short course will (1) understand the accuracy/precision and strengths/weaknesses of the GNSS-IR technique and (2) be able to measure snow accumulation and water levels using data from the global GNSS network. Participants are encouraged to analyze their own GNSS data.

Brief Agenda

October 6, 2021
9:00a – 1:00p MDT
(1500 – 1900 UTC)
Help users install gnssrefl
(python code, Jupyter Notebooks, docker Images)
October 7 – 20, 2021 Participants should run the gnssrefl software and complete assigned
homework. Newcomers to GNSS can also view youtube videos
posted by the instructors on GNSS-specific issues.
October 21, 2021
9:00a – 1:00p MDT
(1500 – 1900 UTC)

– An Introduction to Ground-based GNSS Reflectometry &
Geoscience Applications 
– Review on Software Tools  
– Practicum – How to measure snow accumulation with gnssrefl  
– Practicum – How to measure tides and lake levels with gnssrefl
– Summarize/Questions


Our data show that people who participate in all the activities and allot time to working on the exercises independently learn a lot and gain confidence. Those who do not fully participate often become frustrated and fall behind. We expect participants to:

  • Make sure the gnssrefl code has been installed and is working properly in week 1 (October 6-12).
  • Complete the assigned gnssrefl homework in week 2 (October 13-20); based on your background, watch the suggested online videos.
  • Bring results and questions to the live session in week 3 (October 21).

Computer Requisite and Operating Systems:

We are not able to support Windows Operating Systems at this time.
Participants are expected to have their own computers which should be running linux or OSX.

We have designed this short course to be an active learning exercise. Participants are expected to complete the assigned homework before the online course lectures begin. In the first session of the class, UNAVCO staff will help participants set up and learn how to use Jupyter notebooks, python, and/or docker images.  

This class will also introduce the GNSS reflectometry web app, https://gnss-reflections.org

Instructors, affiliation, and domain expertise:  

  • Kristine Larson (University of Colorado-Boulder, and Central Washington University) – GNSS, GNSS-IR, gnssrefl software
  • Kelly Enloe (UNAVCO) – Jupyter notebooks, python, gnssrefl software
  • Tim Dittmann (UNAVCO) – python, gnssrefl software

Homework and Videos

A GNSS-IR Instructional Playlist can be found here. This YouTube playlist includes a welcome and overview to the course from Kristine Larson, as well as instructions on how to install and run the software.


Please contact communityat symbolunavco.org



  • Date(s): October 6 and 21, 2021
  • Location: Online
  • Deadline: September 3, 2021