Remote Sensing Sensors

Remote sensing, the art of gathering information about the Earth’s surface without physically being present, has revolutionized our understanding of our planet. At the heart of this technology lie remote sensing sensors, the tireless sentinels that capture the Earth’s electromagnetic signals, revealing its hidden treasures and intricate dynamics.

Types of Remote Sensing

  1. Based on Platform: This includes satellite-based (like Landsat) and airborne (like UAVs) remote sensing platforms.
  2. Based on Energy Source: Divided into passive remote sensing, which relies on natural radiation, and active remote sensing, which uses its own signal (like RADAR).
  3. Based on Imaging Media: Involves optical, infrared, microwave, and other imaging technologies.
  4. Based on the Regions of the Electromagnetic Spectrum: Utilizes different parts of the spectrum, such as visible, infrared, or microwave, to capture data.
  5. Based on Number of Bands: Involves multispectral (several bands) and hyperspectral (hundreds of bands) sensors.

Based on Platform

Based on Energy Source

Based on Imaging Media

Based on Regions of EMR

Based on Number of Bands

Remote Sensing Sensors

Image source

Remote sensing sensors can be broadly categorized into two types: passive and active. Passive sensors detect natural energy that is reflected or emitted from the Earth’s surface, typically from the sun. In contrast, active sensors use their own energy source to illuminate the Earth and measure the reflection. Examples of passive sensors include photogrammetric cameras and radiometers, while active sensors include RADAR and LiDAR systems. Each type of sensor has specific applications, depending on the nature of the data required and the environmental conditions under which it operates.

Passive Sensors

Active Sensors

Different Sensors

Sensor Resolutions

Diagram of the high and moderate spatial resolution multispectral Earth observation satellites/sensors launched in the past.
Diagram of the high and moderate spatial resolution multispectral Earth observation satellites/sensors launched in the past. (Kurihara et al., 2018)

Sensor resolution in remote sensing is the measure of a sensor’s ability to capture detail in the data it collects. It determines how finely a sensor can represent or measure something, be it an object, area, or phenomenon, from a distance. High-resolution sensors capture finer details, while lower-resolution sensors provide a more general view. This resolution affects the quality and effectiveness of the data for various applications.

Spatial Resolution

Spectral Resolution

Temporal Resolution

Radiometric Resolution

Different kinds of sensor resolution

Different kinds of sensor resolution (Source: Mahmood et al., 2023)

Major Remote Sensing Platforms

This table provides a comprehensive overview of various Earth observation satellites across diverse organizations and applications.

Resolution: Spatial, Spectral, Temporal, Radiometric Resolution.Satellite SeriesLaunch DateOrbit TypeOrbit AltitudeNumber of SatellitesSensorsSpectral ResolutionSpatial ResolutionTemporal ResolutionRadiometric ResolutionKey Applications
Disaster Monitoring
IsraelDMOSAT-12009Sun-synchronous700 km1Multispectral scanner, SAR imagerVisible, near-infrared, radar2.5m, 10m (radar)5 daysNADisaster response, emergency management, infrastructure monitoring
ItalyCOSMO-SkyMed2007 (first launch)Sun-synchronous450 km4 (operational)X-band SAR imagerN/A3m – 10m12 daysNAFlood and earthquake monitoring, landslide detection, maritime surveillance
GermanyRapidEye2008 (first launch)Sun-synchronous630 km5 (1 operational)Multispectral imagersVisible, near-infrared, red-edge5m4 hours (combined constellation)10-bitNear-real-time disaster monitoring, deforestation detection, infrastructure damage assessment
Climate and Atmospheric Studies
NASA/NOAASuomi NPP2011Sun-synchronous824 km1VIIRS, CrIS, ATMS, OMPSVisible, near-infrared, infrared, ultraviolet375m, 1.4km (infrared)1 dayVIIRS: 10-bit for VNIR and MVIRI, 12-bit for I-bands
CrIS: 14-bit for all bands
ATMS: 12-bit for all bands
OMPS: 10-bit for all bands
Weather forecasting, climate change monitoring, atmospheric composition analysis
EUMETSATMetOp-A and B2006, 2012Geostationary35,786 km2MVIRI, IASI, GRAS, ASCATVisible, near-infrared, infrared, radar1.25km, 4km (infrared)Continuous observation (geostationary)MVIRI: 10-bit for all bands
IASI: 14-bit for all bands
GRAS: 12-bit for all bands
ASCAT: N/A (not applicable, wind scatterometer)
Weather forecasting, storm tracking, air quality monitoring
Oceanographic Applications
NASA/CNES/EUMETSATJason-32016Near-polar1,336 km1DORIS, Poseidon-4, LaRC, ALTIKARadar altimetryN/A10 daysNAGlobal sea level measurement, ocean circulation monitoring, climate change studies
ESASentinel-32016Sun-synchronous850 km2OLCI, SLSTR, SRAL, DORISVisible, near-infrared, infrared, radar300m, 1km (infrared)27 daysOLCI: 12-bit for all bands
SLSTR: 12-bit for VNIR and SWIR, 14-bit for TIR
SRAL: N/A (radar altimeter)
Ocean topography, sea surface temperature, sea surface salinity, marine pollution monitoring
CNSAHY-2A and B2011, 2018Sun-synchronous830 km2GF1, MWRI, SWIHR, SCATVisible, near-infrared, microwave250m, 500m (microwave)4 daysGF1: 10-bit for VNIR and SWIR, 12-bit for MWIR
MWRI: 12-bit for all bands
SWIHR: 10-bit for all bands
SCAT: N/A (not applicable, wind scatterometer)
Ocean wind speed, wave height, sea surface salinity, ice monitoring
Hyperspectral Imaging
Maxar TechnologiesWorldView-32014Sun-synchronous496 km1HyperCube, VNIR, WV-3Hyperspectral, visible, near-infrared3.7m (hyperspectral), 0.34m (VNIR)1 dayHyperCube: 14-bit
VNIR: 12-bit
WV-3: 12-bit
Mineral exploration, environmental monitoring, precision agriculture, vegetation mapping
CNESHySIS2018Sun-synchronous694 km1VNIR, SIFVisible, near-infrared, shortwave infrared1.5m, 75m (SIF)26 daysVNIR: 12-bit
SIF: 16-bit
Environmental studies, vegetation mapping, mineral exploration, pollution detection
GermanyEnMAP2024 (planned)Sun-synchronous678 km1SHySIS, OKSI, APEXHyperspectral, visible, near-infrared6m (hyperspectral), 20m (VNIR)26 daysSHySIS: 14-bit
OKSI: 12-bit
APEX: 16-bit
Geological mapping,
This table provides a comprehensive overview of various Earth observation satellites across diverse organizations and applications.