Seems off the wall
But as the carrying capacity of the UAV is developed you could drop a light UUV
near the target - it would be light beacause it would require minimum propulsion/fuel/battery.
The UUV could be programmed to surface and radio(etc) back to the monitoring platform - UAV/aircraft/mini-sub etc.
The design speci. for the UUV may include many 'mission objectives' other than sonar.
