Next Article in Journal
Fast Optical Humidity Sensor Based on Hydrogel Thin Film Expansion for Harsh Environment
Previous Article in Journal
Automatic and Robust Infrared-Visible Image Sequence Registration via Spatio-Temporal Association
Previous Article in Special Issue
A New Method for Refining the GNSS-Derived Precipitable Water Vapor Map
Open AccessArticle

Low-Cost GNSS-R Altimetry on a UAV for Water-Level Measurements at Arbitrary Times and Locations

1
Research Institute for Applied Mechanics, Kyushu University, Kasugai 816-8580, Japan
2
College of Engineering, Chubu University, Kasugai 487-8501, Japan
3
Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
*
Author to whom correspondence should be addressed.
Sensors 2019, 19(5), 998; https://doi.org/10.3390/s19050998
Received: 1 December 2018 / Revised: 16 February 2019 / Accepted: 20 February 2019 / Published: 26 February 2019
(This article belongs to the Special Issue High-Precision GNSS in Remote Sensing Applications)
Together with direct Global Navigation Satellite System (GNSS) signals, the signals reflected at the water surface can be received by an unmanned aerial vehicle (UAV). From the range difference between two GNSS signal paths, the height of the UAV above the water level can be geometrically estimated using the weighted least squares method, called GNSS reflectometry (GNSS-R) altimetry. Experimental low-cost GNSS-R altimetry flights with a UAV were conducted at the coast of Lake Biwa, Japan. Although the height estimated by the GNSS-R altimeter included large short-term noises up to 8 m amplitude, it agreed well with the UAV altitude measured by the post-processed kinematic positioning. By selecting better weight functions in the least square method and using sufficient temporal averaging, the GNSS-R altimetry achieved accuracy in the order of 0.01 m if a sufficient number of GNSS satellites with high elevation angles were available. The dependency of the results on the weight functions is also discussed. View Full-Text
Keywords: GNSS reflectometry; altimetry; unmanned aerial vehicle; lake water level GNSS reflectometry; altimetry; unmanned aerial vehicle; lake water level
Show Figures

Graphical abstract

MDPI and ACS Style

Ichikawa, K.; Ebinuma, T.; Konda, M.; Yufu, K. Low-Cost GNSS-R Altimetry on a UAV for Water-Level Measurements at Arbitrary Times and Locations. Sensors 2019, 19, 998.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop