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-...