The relevance, strength and likelihood of occurrence of the minefield indicators and signatures used in the airborne and space-borne remote sensing of mine contaminated areas R. Pernar Faculty of Forestry, University of Zagreb, e-mail: rpernar@sumfak.hr R. Šapina Ministry of Defense, e-mail: rozalijas@yahoo.com A. Marinov & D. Vuletiü Croatian Air Forces, e-mail: anmarino@inet.hr; dejan.vuletic@zg.htnet.hr ý. Matiü Croatian Mine Action Centre, e-mail: mirela.mihaljevic@hcr.hr M. Bajiü Faculty of Geodesy, University of Zagreb, e-mail: milan.bajic@zg.htnet.hr Keywords: minefield indicator, remote sensing technology, minefield, suspected area, landmine, UXO, SMART, E-SAR, DAEDALUS, ARC, vegetation, Croatia ABSTRACT: The contamination by land mines and unexploded ordnance (UXO) is an extremely difficult problem that requires engagement of all national resources of the afflicted country, and wide international support. Indeed the main problem is large contaminated area that is not in normal use, this produces very strong impact in the social, economic, political, humanitarian and other domains. In Croatia, in 996, an area of 2000 km 2 was suspected to be contaminated by landmines (assessment of the UN Mine Action Center Croatia), and in 2003 this area is 600 km 2 . Experience in Croatia from 996 to 2003 shows that only 0 % of the suspected area is really contaminated. Similar ratio of the contaminated and the suspected area was assessed in several other countries contaminated by landmines. It therefore follows that a strategic problem for the countries that are contaminated by landmines is to reduce the sus- pected area urgently and proceed by demining in a sustainable manner. Remote sensing tech- nology has potentials for this application. Several international projects were realized or are un- der way, with the aim of applying remote sensing technology and methods to help the humanitarian mine action (several European countries - Pilot project Mozambique; European Commission – PARADIS, ARC, SMART; European Commission and USA - Satellite based GIS for mine action; private consortium – MineSeeker). The actual available airborne sensors cannot detect landmines that lay in the ground and are covered by soil and by weeds (wild vege- tation) for a long time (e.g. in Croatia from the year 99). Several former scientific projects aimed to detect landmines and UXO (Pilot project Mozambique, MineSeeker), but this ill-posed problem was redefined and following projects had more realistic and affordable goals. In this paper, we consider the use of the physical entities (term of reference - minefield indicators) that indicate the presence of contamination by landmines or absence of the contamination, the re- lated features and the electromagnetic signatures. The identification of the minefield indicators started in the project SMART by fieldwork in 48 km 2 of the minefields and the suspected areas, in which different experts collected the relevant information, data and knowledge. This process continued in several iterations from 200 to 2003, while the evolutionary analysis, approval and improvement were applied. The data, information and knowledge that were collected in real contaminated areas were compared with the data contained in imagery and data collected by the airborne passive and active sensors and with the contextual information, data and knowledge. The active sensor was four bands polarimetric Experimental SAR (DLR), while passive electro- 619 New Strategies for European Remote Sensing, Oluiþ (ed.) © 2005 Millpress, Rotterdam, ISBN 90 5966 003 X