Funnily enough, I did find a few satellite sources at the beginning for the map background and noticed that all the ships seemed to be scrubbed from the image. It's an interesting idea, thanks for the comment!
The sources I used were:
- ESRI World Imagery[1] — free satellite tiles, high-res, but ships are stripped out from the imagery
- NASA GIBS - VIIRS[2] — near real-time daily satellite imagery from NASA, but resolution is ~375m so ships aren't visible anyway
- Mapbox Satellite[3] — high-res and looks great, but same deal — ships are scrubbed from the composited imagery
1. https://server.arcgisonline.com/ArcGIS/rest/services/World_I... 2. https://earthdata.nasa.gov/engage/open-data-services-softwar... 3. https://www.mapbox.com
Ai2 has vessel detection models for Sentinel-1 and Sentinel-2 (ESA) along with Landsat 8, Landsat 9, and VIIRS Nighttime Lights (NASA/USGS/NOAA):
- Sentinel-2 (10 m/pixel): https://github.com/allenai/rslearn_projects/blob/master/docs...
- Landsat (15-30 m/pixel): https://github.com/allenai/rslearn_projects/blob/master/docs...
- VIIRS Nighttime Lights: https://github.com/allenai/vessel-detection-viirs
I think you can see these vessel detections at https://app.skylight.earth/ ("Try out a limited version as a guest") but they seem to be delayed by 48 hours.
VIIRS is very low resolution but you can make out vessels with reasonable accuracy in the night-time images.
VIIRS covers most locations at least once per day, but the other sensors capture a given location only once per 5-10 days (although when combined, Sentinel-1/Sentinel-2/Landsat should provide close-to-daily coverage).
There is also a lot of jamming, manipulating, and fake AIS broadcasting going on
https://windward.ai/blog/gps-jamming-disrupts-1100-ships-in-...
It turns out during a war having real time satellite imagery of shipping would be a poor choice.