Three comments:
I agree with everything Erik said, especially about the nifty political manuevering.
If you're going to go into getting research points from observations (I really like that idea too, btw), then I would advocate passive sensors being able to gather data too. After all, EM emissions spectrum gives lots of information - think about EC-121, submarines getting acoustic signatures, and Russian trawlers. If you cut the probability of a particular type of sensor acquiring information from what you were planning for actives (i.e. you need all sensor types to get the same level of information), then this also makes such intelligence gathering more expensive. You might also put a threshold on signal strength (e.g. greater than 10x detection level) before it's possible to acquire information.
I also like the concept of requiring the data be transmitted as you put in your last paragraph.
Johh