I just found out about Aurora last week and I've been playing pretty heavily since.
I cheated pretty heavily for my first game so I could learn the interface without worry about being steamrolled by a ruthless NPR, and I'm almost ready to start a real game up.
However, before I conclude my current game I was hoping to find a colony or home planet of at least one of the two hostile NPRs I've encountered. So far I've encountered ships but have never seen any colony indication. I've got maxed tech with insane sensors and a ship dedicated to finding everything in a system:
First of: are you actually sure that the ships you encountered were NPRs and not spoilers?
Some spoilers do not have colonies as such, but only ships.On finding NPRs: All colonies emit thermal signatures and most emit EM signatures, while they do not present a radar cross section. So a colony itself can only be found by passive thermal or EM sensors, not by active search sensors. However you might still find the buzzload of ships and shipyards that are associated with many truly active colonies by the active sensors on your ship.
While most NPRs are trans-newtonian, some are not and might not have ships or space installations. You are unlikely to find these with active sensors.Yet, your active sensor also provides quite a large active EM emission, which might be detected by a colony, e.g. through ground-based tracking stations. In the worst case, the aliens would have ample warning of your approach and be able to evacuate their ships (but not shipyards) before you get in range (and might find nothing left for your sensors to detect).
So my suggestion would be to use a design heavily loaded with passive thermal and EM detectors, instead of the active ones you use. If you use an active sensor, it might as well have a larger resolution, because the easiest thing to find are civilian ships, which masses normally range in the tens of thousands of tons. The same sensor with a resolution of 200 would give you a much larger coverage.
Other methods include following their ships, and negotiating long enough till you have a trade treaty (after which it will be very easy to follow civilian traffic).
edit: What does the acronym GPS stand for in the sensor array information, and what does the number mean?
The GPS stands for the amount of active emissions an array emits (yeah I dont actually know what the acronym stands for). This is detectable by EM sensors when the sensor is switched on.
For instance an EM sensor might read
“EM Detection Sensor EM2-12 (1) Sensitivity 12 Detect Sig Strength 1000: 12m km” . So this sensor could detect a 1000 GPS signature at 12m km. Your “
Active Search Sensor MR42690-R40 (10%) (1) ” has a GPS of 360,000 so the above mentioned EM sensor could detect it at 360*12=4320m km. I.e. pretty much exactly your range. If the EM sensor was twice as large it would give ample warning.