Ah, right this is what I was trying to get at. Any secondary target has to be within the *missiles* sensor range? Missile borne sensors would seem only to be useful for firing at extreme engagement ranges. Which is fine. If I survive to later tech levels, I might look into a size 2, very long range AMM which could spare the space for a sensor.
Right now, the biggest PD sensor I can build will see size 6 missiles at a little over 5m km. I might build one to mount on a dedicated sensor ship
Will a PD ship with a large sensor automatically guide the survivors of one AMM salvo onto another wave if they can see it then? Also, going off at a bit of a tangent, sensors currently share data, but don't stack, right? So if I have 2 sensors of the same type running, covering the same area they will both report a target they see, but only at their own detection values. How about a ship system that lets you share data between sensor platforms in real time to create a virtual, larger system?
So, my monster nothing-but-sensors-and-engines beast sits a little to the rear of the formation, blasting space with 1. 21GW of sensor energy, and data links its feed to other ships within x km (LOS laser link, values based on laser research and component size?) The receiving ships integrate that into their own sensor data, and gain an effective increase in their own sensor size / values. It makes dinky little backup sensors on gun heavy designs much more tactically useful, but also introduces a point of weakness for a fleet taking advantage of it. If the Light of the Heavens goes down, no-one can see anything
Early on especially, it might let low tech fleets form a giant interferometer, and compete with more advanced foes on engagement range. But as battle is joined, and ships and sensors go down, they get harder and harder to see. . .
In real world physics, you really can do something similar, by using 2 smaller sources to illuminate an object, and computer mutilating the output to be as if one much larger source was used