REMOTE SENSING
REMOTE SENSING
With mounting pressures on the UK’s ageing infrastructure networks from ever increasing numbers of service users and unpredictable weather conditions, asset owners are looking for cost-effective solutions to provide a long-term view of network conditions to prevent future failures. Asset owners specifically need to be able to effectively monitor activity to understand the environments in which they operate. Remote sensing can provide insights without visiting a site, reducing carbon, and enabling more focused intervention and monitoring.
Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object (in contrast to in situ or on-site observation). This enables the detection and monitoring of the physical characteristics of an area by measuring its reflected and emitted radiation. The sensors are usually on space-borne satellites or aircraft – with the advancement of drone technology – some of these sensors can be mounted onto small, terrestrial drones. There are various satellite constellations orbiting the Earth at various distances from the surface – low-Earth orbiting satellites are approximately 150-2,000km above the Earth, medium-Earth orbiting satellites 2,000-35,000km above Earth and high-Earth orbiting satellites are over 35,000km above the Earth. Medium-Earth orbiting satellites take around 12 hours to circle the Earth. The European Space Agency’s Galileo satellite, used for global navigation satellite systems (GNSS) is one such medium-Earth orbiting satellite.
DESIGN FEATURES
Remote sensing can be split into two different types – active and passive. Active sensors involve the sensor emitting the signal itself to the Earths surface, then receiving the reflection back and recording the results. In contrast, passive sensors respond to external stimuli, they record the natural energy that is reflected or emitted by the Earths surface and in most cases solar radiation from the Sun.
THE MAIN BENEFITS OF REMOTE SENSING ARE:
- non-invasive technology (contact free) so deployment of sensors or hardware on the ground is not necessary
- repeatable enabling the detection of change and trends over time
- speed of delivery: satellite data may be obtained and analysed in a matter of weeks.
- the possibility of proactively identifying potential triggers for ground movements, drainage problem areas and geotechnical hazard locations.
- screening technology that can be used directly or indirectly for ground monitoring, targeted intervention, or mitigation measures.