- ADS-B aircraft surveillance from space — LEO satellites carrying 1090 MHz receivers decode ADS-B Out transmissions from aircraft anywhere on Earth, including oceans and polar regions where ground radar cannot reach. The technique extends global air traffic awareness but carries real latency and signal-collision constraints that buyers must understand before specifying it.
- AIS vessel tracking and dark-ship detection — Space-based AIS receivers capture VHF transponder broadcasts from vessels worldwide, but gaps in that record are where the real intelligence begins. Cross-referencing AIS silence against SAR and optical detections exposes vessels that would prefer not to be seen.
- Commercial SAR rapid flood extent mapping — Synthetic aperture radar maps flood extent in any weather, day or night, by detecting the near-zero backscatter of smooth open water. Commercial constellations now cut revisit from days to hours, but wind and forest canopy introduce real ambiguities that analysts must account for.
- GNSS radio occultation atmospheric profiling — GNSS radio occultation turns GPS and GLONASS signals into vertical slices of the atmosphere, yielding temperature, pressure and humidity profiles with roughly 100 m vertical resolution and no need for calibration targets.
- Spaceborne lidar canopy height and forest structure — ICESat-2 and GEDI fire laser pulses through forest canopies and time the returning photons to map vertical structure at scales no passive sensor can reach. Each system has distinct geometry, sensitivity and coverage gaps that buyers must understand before committing to a monitoring design.
- Multispectral vegetation index monitoring — Multispectral satellites measure how plant canopies absorb and reflect sunlight, revealing crop stress, biomass change and land-cover shifts weeks before they are visible to the eye. This page explains the physics, the band configurations of the main sensors, and the real limits imposed by cloud cover.
- Ocean colour and coastal water quality retrieval — Sentinel-3 OLCI, MODIS and VIIRS measure water-leaving radiance across visible wavelengths to derive chlorophyll-a, suspended matter and dissolved organics. This page explains the physics, the algorithms, and the hard limits that apply near coastlines.
- RF emitter geolocation from space — Clusters of LEO satellites can fix the position of any radiating emitter using time and frequency differences of arrival, no cooperation required. Accuracy depends on constellation geometry, ephemeris quality, and signal duration.
- SAR interferometric surface deformation mapping — InSAR compares the phase of repeat SAR passes to map ground displacement at millimetre scale, revealing subsidence, uplift and fault creep invisible to optical sensors. Coherence, atmospheric delay and imaging geometry all shape what the technique can and cannot see.
- Sentinel-3 radar altimetry for sea level and inland water — Sentinel-3 SRAL measures sea surface height, wave height and inland water levels using SAR-mode radar altimetry. This page explains the physics, the 27-day repeat cycle, and where the method breaks down.
- Thermal infrared land surface temperature retrieval — Thermal infrared sensors measure emitted radiance from the Earth's surface, which is converted to land surface temperature through emissivity correction and atmospheric adjustment. Resolution, revisit and cloud cover set hard limits that no processing chain can overcome.
- Tropospheric nitrogen dioxide column mapping — TROPOMI on Sentinel-5P retrieves tropospheric NO2 columns daily at 3.5 × 5.5 km, exposing industrial point sources, shipping corridors and urban traffic patterns that ground monitors miss entirely.
- Very-high-resolution optical change detection — Sub-metre commercial optical imagery from Maxar, Airbus and Planet can resolve individual vehicles, construction equipment and structural damage. This page explains how change detection works, where it breaks down, and what the resolution-versus-revisit trade-off means in practice.
- Video from space for transient activity detection — Commercial video satellites capture short clips at sub-metre resolution, revealing moving vehicles, vessel wakes and aircraft invisible in still imagery. Frame rate, footprint and data volume impose hard limits that any serious programme must plan around.
- VIIRS day-night band nighttime light monitoring — The VIIRS Day-Night Band detects low-radiance visible and near-infrared emissions at 750 m nadir resolution, enabling electrification mapping, economic proxies, gas-flare monitoring and conflict damage assessment. Saturation, lunar contamination and a broken heritage link to DMSP-OLS are the limits every analyst must account for.