How GNSS SNR Values Are Connected to Antenna Heights; the Geometry of SNR-Based GNSS Interferometric Reflectometry

You may know what formula I am talking about; one of the most famous formulas in GNSS reflectometry that magically links the reflected SNR values, satellite elevation angle, and the signal wavelength to the antenna height. I have created a short animated video to explain where this formula comes from.

In October 19, 2020, at 11:00 a.m., when I was defending my master’s thesis, which was on the applications of GNSS interferometric reflectometry, both my committee members asked questions about the origin of this formula. First, Dr. Richard Kelly, asked me how we can geometrically connect the SNR to the antenna height, and I referred to some basic trigonometric equations to clarify the geometry of SNR-based GNSS-Reflectometry. Afterwards, Dr. Grant Gunn, asked how bending effect and penetration delay can be ignored in this technique; so, I refered to its geometry and mentioned that this technique is classified as a “phase altimetry” method, in which the delay and bending effects are significantly reduced compared to those method categorized as “range altimetry”.

Although I successfully passed my defense, I felt that the origin of this formula might be unclear for researchers whose main fields of interest are not GNSS reflectometry. Therefore, I decided to create this short video to simply explain how the antenna height can be retrieved from SNR values. This video is a part of my i-poster submitted to the Global Water Future 4th Annual Open Science Meeting (GWF2021) in where a large number of researchers and scientists present their recent findings on Canada’s water future. As I guess that many of them are not super expert in GNSS reflectometry, I decided to create this short video and put it in my poster. The link to my poster will be shared when it becomes available.