Overview
Kpler Vessel Observation finds ships in satellite imagery from three sources: Sentinel-1, Sentinel-2 and Airbus SPOT 6. It then matches each detection to a known vessel using Kpler AIS.
Each record gives a satellite-observed position, the matched vessel identity (MMSI, IMO, name, Kpler vesselUid), a 0–100 correlation score and the distance in metres from the vessel's AIS position at capture time.
Satellites locate a ship whether or not it is broadcasting. AIS carries the track between satellite passes.
Kpler does not task satellites. We process imagery that the providers already collect over set areas of interest (AOIs).
Satellite sources
Kpler currently uses ESA Copernicus missions, used for wide-area detection, and one commercial Airbus satellite, used for high-resolution detail.
Spec | |||
Operator | ESA / European Commission (Copernicus) | ESA / European Commission (Copernicus) | Airbus Defence and Space |
Sensor | C-band synthetic aperture radar (SAR) | Multispectral optical imager (MSI), 13 bands | Optical, panchromatic + 4 multispectral bands |
Resolution | ~5 × 20 m (Interferometric Wide mode) | 10 m (best bands); 20 m and 60 m for others | 1.5 m panchromatic; 6 m multispectral |
Swath | 250 km (IW mode) | 290 km | 60 km |
Works through cloud / at night | Yes | No: daylight and clear sky needed | No: daylight and clear sky needed |
Satellites in orbit | Sentinel-1C (launched Dec 2024) and 1D (launched Nov 2025); 1A in extended service | Sentinel-2A, 2B and 2C (2C launched Sep 2024) | SPOT 6 (SPOT 7 failed in Mar 2023) |
Nominal revisit | 6 days with a two-satellite pair at the equator; more often at higher latitudes and where swaths overlap | 5 days with two satellites at the equator; more often at higher latitudes | Daily over our contracted AOI |
Revisit we see in practice | 2–3 days | 2–3 days, cloud-limited | ~Daily |
Local overpass time | Dawn / dusk orbit | ~10:30 am | ~10:00 am |
What it gives us | Ship presence and size, day or night, in any weather | Ship presence, size and heading on clear days | Hull outline, deck layout, superstructure, wake and berth, enough to tell sister ships apart |
Nominal revisit is the published value for the constellation. "In practice" is what Kpler observes over its AOIs once overlapping passes are counted.
Imagery quality and technical notes
Detection vs identification. At 10 m (Sentinel), we can detect a vessel and measure its size but recognising it is more challenging. At 1.5 m (Airbus), hull markings, deck layout, superstructure and wake are visible. Identification depends on that detail.
Radar vs optical. Sentinel-1 radar sees through cloud and works at night. Sentinel-2 and SPOT 6 are optical, so they need daylight and a clear view. AIS carries the track between usable images.
Cloud threshold. Airbus scenes are accepted at up to 30% cloud cover today. Raising the threshold catches more vessels but leaves more of the scene obscured.
Minimum vessel size. The Airbus pipeline targets vessels of 30 m and longer today. Going smaller increases false positives and makes identification by human analysts more time consuming.
Latency (Airbus). The satellite passes at about 10am local time. Ortho-rectified scenes arrive within 6 hours, and automated detection takes up to 3 hours. Data is delivered the same day, about 9 hours after acquisition. We don’t have a set tasking order, we receive all imagery captured for other participants within this large AOI.
Correlation evidence. Every matched record carries a 0–100 correlation score and the distance in metres to the vessel's interpolated AIS position. Clients can filter to what they trust, for example a score above 90.
What "dark" means. A dark detection is a vessel with no AIS signal within the time and location buffer. It is not proof of wrongdoing. In one recent sample, 53% of dark detections were vessels under 15 m, which are not required to carry AIS.
Snapshots, not surveillance. Each detection is what a satellite saw at one moment. Short visits between passes can be missed, so counts are a minimum level of observed activity.
What the API returns today. It returns AIS-correlated positions with vessel identity, not the image itself. Image chips and uncorrelated (dark) positions are on the roadmap.
FAQ
What history is available?
Middle East berth detections are available from 1 January 2026. Airbus SPOT 6 imagery starts in August 2026, when the contract began. Each API call can look back up to 366 days. History before 2026 is not yet offered.
What is the revisit rate?
Airbus SPOT 6 revisits the contracted AOI about daily at 1.5 m. Sentinel-1 and Sentinel-2 each give a usable pass every 2–3 days over our AOIs. Sentinel-2 passes depend on cloud cover. Combining all three gives more than one look on most days.
Which AOIs are covered?
Airbus covers the Persian Gulf, the Strait of Hormuz and the Gulf of Oman. That is about 350,000 km² imaged daily, or 6.67 million km² a year. Sentinel-1 and Sentinel-2 cover a wider area, including Middle East liquids berths and terminals.
What can we say about coverage and dark detections?
In August 2026, 51% of vessel detections at non-Iranian Middle East berths were vessels not broadcasting AIS when the image was taken. In the Strait of Hormuz, about 50% of detections are dark, compared with about 20% globally. About 80% of Hormuz detections auto-correlate to a validated AIS track. Over a 51-day baseline, Airbus imaged 1.47 million km² across 241 segments, averaging 29,000 km² a day and peaking at 65,000 km².