Remote Sensing with Signals of Opportunity

James L GarrisonSchool of Aeronautics and Astronautics

School of Electrical and Computer Engineering (by courtesy)Division of Environmental and Ecological Engineering

Objective: Demonstrate land and ocean remote sensing using communication satellite signals

• Heritage – demonstration using navigation (GNSS) signals in L-band

• Recent results – ocean wind sensing with XM radio (S-band signals)• Future/Ongoing: Direct Broadcast (Ku-band) for high-

resolution ocean winds, UHF for deep-penetration soil moisture

Remote sensing with GNSS Reflections

Soil Tg

Vegetation canopy

PT

PRa GPT

Remote sensing with GNSS Reflections

(From Chapron and Ruffini, GNSS-R workshop, Barcelona. Photo taken at Le Conquet, Brittany)

Receiver

glistening zone

glistening zone

Fundamental Physics:Rougher surface =

larger distribution in path delays

This phenomenon can easily be observed at sunset:

(water is calm inside the red ellipse)

XM Radio Bistatic Radar• Ambiguity function – key feature to perform “range-

Doppler mapping”

Spring 2011 Goal• Research UHF satellite availability and antenna options• Collect raw samples of Ku-band and UHF signals • Generate ambiguity function from raw data –

demonstrating ability to detect and process reflected signal.