With the recent advances in Gravitic engines, and Grav Cannons, and with the study and implementation of Drakh Hyperspace generators, it became important for the Mrrshan to gain information on spacetime itself before tearing holes in it. The reason for this is twofold: First, If one tears a hole in a fragile part of space-time, one risks opening an un-closable rigt. The second reason is one of pure efficiency, if one knows where the weak spots are, and where they can be pressed to open a stable rift, then one can use less energy to do so.
The Gravitic Flux sensors work by scanning through space-time itself, and registering rifts and intrusions, so that a safe course can be plotted. In addition, the sensors are sensitive to realspace intrusions on space time. The reasoning behind this is as follows: Space time is curved, and is fluid, based upon what objects exist on it. Since every object has mass, any given object exerts a force on space-time, bending it. Gravitic flux sensors operate by measuring these exertions on space time, and translating them into 3 dimensional sensor images. Since the sensors operate on space-time, and not on objects themselves (Although they can be used to do this) they are capable of detecting cloaked vessels with astonishing accuracy, rendering just about any cloaking device (besides those that phase objects out of the normal realm of existance) useless.
Gravitic Flux Sensors, when combined with normal sensors are incredibly accurate, down to the micrometer level. However, Gravitic flux sensors are susceptable to gravitic interferance, a sufficiently large gravitational anomaly (Such as that of a black hole) can cast a mass shadow that can hide smaller objects, such as fighters. However, the sensors are sensitive enough to allow operation within solar systems, and within close proximity to Stars and massive planets. Also, because it operates by detecting Gravitic Flux, power sources using gravity or micro-singularities stand out like a beacon.