Table 1.

Microwave and optical sensor technologies applied in the measurement campaign.

Institute (Country), abbrev.		Microwave technology			Optical technology
		Band	Frequency	Polari-sation	Instrument	Specs	Ref.
Inst. Telecom. (PT)	ITP	S - K	2–20 GHz	VV			54
			(2 GHz bandwidth)
Uni. Stirling (GB-SCT)	UoS	C	5–6 GHz	Quad pol			55
		X	9.5–10.5 GHz	VV
Uni. Politècnica de Catalunya (ES)	UPC	L1 (GNSS-R)	1.5–1.7 GHz	LHCP / RHCP			56
ITC Twente (NL)	ITC				ASD	300 –2500 nm
Uni. Oldenburg (DE) / Uni. Leiden (NL)	UoO/L				RGB camera	5 MP	57
					GroundSPEX