Originally Posted by stickyjeans69

because a cessna 172SP will put you 195,000 dollars out of the pocket with the default configuration, why not make it 205,000 when paying those kinds of dollars.

http://www.airliners.net/open.file/1093864/L/

as far as the GPS measuring position on the earth and not altitude, so what?. think of it as a grid. you have the X and Y axis when using any GPS, even a 10,000 dollar one. the airplane adds the Z axis (altitude), and a GPS isn't for altitude every airplane worthy of requiring a PPL has an Altimeter in it. the GPS inside of an airplane differenciates GREATLY from the one in your car in the fact of the database it uses for maps. the one displayed there also has multiple features including a COM radio (communication radio) and TAWS (traffic awareness warning system) that reports information recieved from nearby Controllers on aircraft position and altitude. in the picture i posted earlier to the right of the aircraft you see a Triangle with two digits above it -08. the aircraft being reported is 800 feet below you. the one to the left in Yellow is 1200 feet above you and climbing as indicated by the up arrow. the GPS detected it as a possible threat to safety and that's the reason it's yellow. before you even care to notice the traffic you hear "Traffic Traffic" and that target is flashing white and yellow for about 10 seconds if it gets within i believe 2 miles it turns red and keeps saying traffic untill you're clear of any possible collision. midair crashes generally aren't very pretty . to further elaborate though, the information posted on an aviation GPS as such is

Major Highways
Terrain data
Airways
VOR's
NBD's
navigation Fixes
Airports
Nearby Traffic
Airspace Class (will show Class D, Class B, and Restricted airspace)

lets see all that from your 100 dollar GPS

So basically its just a bunch of GPS receivers that are aware of eachother's position and can determine by the vector of each unit what it should avoid coming close to? Give me a year and I'll do it for $140. I can even cut the satellites out of the picture completely this way, the location of the space the unit is travelling through will be determined by the relative location of the other units and used as a dynamic reference by ALL of the "gps" units.

Seems kinda antiquated to have all of that extra information on airports and stuff, though. I wouldn't bother with that. I would, however, develop a system that integrates with the "units" and can provide specific information about points of interest to the unit. Kind of like a survival instinct for electronics. Hmm, GPS could lead to self aware machines.

The reason it costs so much is because they made it too complicated on purpose.

This would probably be more useful to intra-spacial travel though. In other words, "space flight." Even though its not really flight, more like scrolling.