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The Earth Observation index

Sensors, providers, use cases — indexed neutrally. No sponsored placement. Start with the sensor doctrine, then browse providers or the use-case matrix.

SIMULATED

SAR

L · S · C · X BAND

All-weather, day/night radar. The backbone of guaranteed-cadence monitoring.

Resolution
0.25 – 30 m
Revisit
Hours (constellation)
Conditions
All-weather · day/night
◆ InSAR-capable constellations listed
Providers — Airbus Defence & Space · Arlula · Capella Space · Copernicus Programme (EU/ESA) · e-GEOS
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Sensor 101 — SAR
Synthetic Aperture Radar (SAR) actively illuminates the ground with microwaves and measures the reflected signal. Because radar penetrates clouds and needs no sunlight, SAR is the only sensor class that can promise a genuine, guaranteed revisit — every pass, every time. Metal and hard surfaces reflect strongly (bright); smooth water reflects the signal away (dark). Speckle is inherent and requires trained interpretation. SAR underpins dark-vessel detection, flood extent, deforestation alerts, and — through repeat-pass interferometry (InSAR) — millimetre-scale ground deformation.
REAL IMAGERY

Optical VHR

VIS · 15 – 50 CM

15–50 cm human-interpretable imagery. Identification, damage, evidence.

Resolution
0.15 – 0.5 m
Revisit
Daily where clear
Conditions
Clear sky · daylight
Providers — Airbus Defence & Space · Arlula · BlackSky · Planet · Safran.AI (Preligens)
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Sensor 101 — Optical VHR
Very-High-Resolution optical sensors capture the visible spectrum at 15–50 cm ground sample distance — sharp enough to identify individual vehicles, aircraft type, cargo, structural damage and construction progress. Human-interpretable and admissible as evidence. Limitations are physical: cloud cover blocks the view, night imagery requires a different sensor family, and high-latitude winters degrade tasking feasibility. Typical decisions: damage assessment, activity confirmation, insurance and compliance evidence.
REAL IMAGERY

Multispectral

VIS · NIR · SWIR

3–10 m visible + NIR. Vegetation, water, land cover at field scale.

Resolution
3 – 10 m
Revisit
1 – 5 days (open + commercial)
Conditions
Clear sky · daylight
Providers — Arlula · Copernicus Programme (EU/ESA) · Kayrros · Planet · Satellogic
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Sensor 101 — Multispectral
Multispectral sensors capture a handful of discrete bands beyond human vision — red-edge, near-infrared and shortwave-infrared. This unlocks vegetation indices (NDVI, EVI), moisture content, chlorophyll, water quality and land-cover classification. Field-scale, not object-scale. The workhorse of agriculture, forestry, land-use compliance and environmental monitoring — with Sentinel-2 and Landsat providing free global coverage every few days.
SIMULATED

Hyperspectral

200+ CONTIGUOUS BANDS

~30 m, 200+ bands. Material and species identification.

Resolution
~30 m
Revisit
Weekly to monthly
Conditions
Clear sky · daylight
Providers — Pixxel · Planet
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Sensor 101 — Hyperspectral
Hyperspectral imagers capture hundreds of narrow, contiguous spectral bands — giving each pixel a full reflectance signature. This lets analysts identify materials, minerals, crop species and pollutants directly from their spectral fingerprint, rather than inferring them. Resolution is coarser (~30 m) than multispectral, but the information density per pixel is orders of magnitude higher. Core to mineral exploration, precision agriculture, environmental forensics and defence material identification.
SIMULATED

Thermal IR

LWIR · 8 – 14 μm

Emitted heat, day and night. Wildfire, industrial, energy loss.

Resolution
3 – 100 m
Revisit
Sub-hourly to 8-day
Conditions
Day and night · cloud blocks
Providers — Hydrosat · OroraTech · SatVu · USGS / NASA (Landsat)
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Sensor 101 — Thermal IR
Thermal-infrared sensors measure emitted heat rather than reflected sunlight, so they work day and night. They surface wildfires, industrial heat signatures, flare stacks, urban heat islands, building energy loss and — with high-cadence constellations — utilisation of specific industrial sites. Cloud still blocks. Resolution ranges from 100 m (open Landsat TIRS) down to ~3 m (SatVu-class commercial).
SIMULATED

RF/SIGINT

VHF · UHF · S · X · Ku

Detects and geolocates emissions. Dark vessels, spectrum activity.

Resolution
Geolocation ~500 m
Revisit
Hours (constellation)
Conditions
All-weather · day/night
Providers — HawkEye 360 · Spire · Unseenlabs
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Sensor 101 — RF/SIGINT
Radio-frequency intelligence satellites listen rather than look. They detect, characterise and geolocate active emitters — marine radars, VHF communications, aviation transponders, satellite uplinks — regardless of weather or lighting. Uniquely valuable for dark-vessel detection (ships with AIS off but radar on), spectrum monitoring, denied-area activity and cross-cuing optical or SAR tasking to a specific coordinate.
SIMULATED

Video & SAR Dwell

VIS · X BAND DWELL

Motion from orbit. Pattern-of-life, throughput.

Resolution
1 – 3 m video
Revisit
Tasked dwell windows
Conditions
Clear sky (optical) · all-weather (SAR)
Providers — SEN · Umbra
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Sensor 101 — Video & SAR Dwell
Video and staring-mode sensors dwell on a scene for seconds to minutes rather than a single snapshot — producing motion tracks of vessels, vehicles and aircraft. SAR dwell (spotlight mode) does the same through cloud. This enables pattern-of-life analysis, port and airport throughput measurement, convoy tracking and cross-cuing of other assets. Data volumes are large; tasking is by dwell window rather than area.
SIMULATED

Gas & Emissions

SWIR · CH₄ · CO₂

Methane and CO₂ plume quantification. Compliance driver.

Resolution
25 m – 7 km
Revisit
Daily (regional) · weekly (site)
Conditions
Clear sky · daylight
Providers — Carbon Mapper · Copernicus Programme (EU/ESA) · GHGSat · Kayrros · MethaneSAT (EDF)
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Sensor 101 — Gas & Emissions
Imaging spectrometers tuned to shortwave-infrared absorption bands detect and quantify methane and CO₂ plumes at point sources — well pads, pipelines, landfills, coal mines. Emission rates are reported in kg/hr with a detection threshold that depends on wind and background. Now a direct compliance driver under OGMP 2.0, the EU Methane Regulation and equivalent frameworks. Sentinel-5P gives daily regional context; GHGSat and Carbon Mapper deliver site-scale quantification.