Guardians of the Stars
Most sensors are still conventional. RADAR, LIDAR, EM radiation sensors, advanced optics, etc.
Development of CM/CG technologies however has allowed for advanced gravity sensors that can map gravity field. This is most effective at detecting large objects with significant mass and relatively low speed. However objects emitting CM or CG fields make big gravity ‘ripples’ allowing detection at much greater ranges proportional to the type and power of the field they emit.
The other recent sensor technology is subspace sensing capability. The advantage of subspace is it’s FTL nature, making it the only sensor that works in real time beyond ~360,000 km. However the best use of a subspace sensor outside receiving subspace signals is to catch reflections or echos of subspace particles as they bounce off of objects. Most FTL travel makes a very large amount of subspace particles.