The European Space Agency (ESA) funded ISSN project is developing a platform for remote monitoring based on data fusion between in-situ intelligent sensors and satellite based measurements. With satellite communications, innovative sensors and embedded intelligence, this sensor network platform will range from sub-sea to central office. The ISSN will provide an end-to-end solution for time-critical monitoring in remote, isolated and harsh regions. Our reference application will be sub-sea oil and gas leak detection.