Gravimetric: Hidden Asteroid Belts
Info: There may even be a chance that Faction NPCs show up and drop Faction Items/Implants

Magnetrometric: Profession Site, mostly ArcSal (Archaology & Salvaging)
Loot: T2 Rig BPCs, Datacores, common & rare Salvaged Materials

LADAR: Complexes & Gas Clouds (There are also reports about RADAR Gas Clouds, so they don't seem to have a fixed sig. type)
Complexes most of the time escalate when you shoot the Structures in the second Stage

RADAR: Profession Site, mostly Hacking
Loot: Enc. Skillbooks, Decryptors, Interface BPCs & Components

2'147'483'647 km = 14.31 a.u.
10 a.u = 1500000000
5 a.u.= 750000000

SIFT -- 0.5 a.u.
COMB -- 1.0 a.u.
PURSUIT -- 2.0 a.u.
QUEST -- 4.0 a.u.

coppied from Gizza thank you