NAVIGATION AIDS:

In order of usefulness:
1. Tactical Nav system
2. Singularity engine SETA * 
3. Trading Extension
4. MARS * system
5. Docking Computer speeds things up a lot - available at 1-7P
6. Ecliptic Projector
7. Binoculars 
8. SETA * Boost Upgrade 
Cost
505
144
32.400
38.448
10.800
4.890
1.440
88.560
Command
N
P
I
U
D
F5
Alt
Shift-J
The manual is pretty good at telling what these do.  EXCEPT:
    * The SETA engine is referred to as SINZA in the manual.
    * The MARS system "Motion Analysis Relay System" (autopilot) - for combat aka ZIPER Target
      Projector, found at Split SED 6-0S
    * The SETA boost is referred to as SINZA boost in the manual. Found at 2-1A