Navigation Methods for Space Fairing Vehicle

Is GPS the best method of navigation for suborbital vehicles?

Yes. It's also probably the cheapest.

Cheap I know about. Besides the data transmission equipment to get telemetry back down to earth, a cheap GPS NAV system can be constructed for around $1500 USD - basically from scratch. Not too bad for vehicle that could spriral up into the millions in cost.
I read about data over Amatuer band on Armadillo's site. There are no doubt distance limitations, just don't know what they are and don't know the details about what type of equipment.
Any idea on how to get the data back to a ground station?

scaled's FNU is probably alot better than any fully gps thing, but gps is cheap and easy, so it'd say it's the way to go until we get real, long distance commercial flights going.

Likely the same way that the data is sent from the ground position to the sattelite and back again: simply beaming it back in forth in a standardized format. Obviously, altitude might be a minor hitch, so the launch site might be used as a telemetry point due to its stationary nature and known position -- think of it as a sattelite at ground level.

Welcome to the boards, ArcheAngel! You've made a great start.

Satellite phone? How fast can sat phones track?

Data over the ham bands is fine until the vehicle becomes a business operation, and then it must cease, according to FCC rules. Well.. a gray area actually. If a paying passenger has a ham license, and wants to operate from the vehicle, then the could probably still use said transponders on the vehicle. As for the distance limitations, for a suborbital ballistic trajectory, there really are no limitations depending on the band they choose to operate on. They might to well to operate on a band with less chance of interferance (QRM), like 10Ghz. Amateur Radio operations in space have been going on since the early sixties.

Some kind of inertial navigation is of course essential and unavoidable. The cool part is that gyros and accelerometers are rapidly coming down in price, you can outfit your hobby robot with complete IMU based on MEMS chips for under a hundred bucks.

Inertial is handy. And a lot more accurate. A combination of inertia and GPS means neither has to be very reliable which cuts costs.

Also teams should be getting practice with inertial stuff before it really matters.

I agree with having systems other than GPS for backup and comparison. GPS and compasses may run into problems in the next 100 years or so due to the Earth's magnetic wobbling wildly on it's way to reversal(or so the scientists say). Also, we are going to need some kind of reference-point nav system on Mars where there is no magnetic field.
Being able to know where you are for the purpose of planning where you are going and also knowing where you have been...are at the core of any effective transportation system. Precisely why I am looking at Nav systems first.
Any links to enertial navigation info?
I did find that Analog Devices sells accelerometers for around $8 each...just have to get an EE to design a system around that:)

http://autopilot.sourceforge.net/ would be a good place to start. Its slightly dated already, though. Look around in hobby robotics sites for more.

linkage:

http://www.interestingprojects.com/crui ... trol.shtml

how to build a guidance system on the cheap.

You can get really cheap solid state gyros for model aircraft... the drift like crazy but you just add more or compare them in software to other stuff...

GPS has absolutely nothing to do with the earth's magnetic field, so even if it were to suddenly "flip" as some say it might, GPS wouldn't be affected. True north (the north pole), would still be the north pole, even if magnetic "north" were near the geographic south pole.

GPS would work fine on mars too, assuming we put a billion $+ constellation of satellites in orbit.

but it would have just about everything to do with the electronics in the GPS satelittes working correctly. if a magnetic reversal were to take place (note that i'm not saying it will) i doubt most electronics anywhere in orbit or on the ground would work properly

btw nasa has some limited plans for gps-like solutions on mars

I would be interested to find any IEEE published material on this subject. I don't have access to their material any more since I let my membership lapse. (rather costly for my near-no-budget company)
The earth's magnetic field is very week I'd wager - compared to the magnetic field of a more 'localized' system such as an AC/DC circuit carrying several AMPs and therefore I'm not too certain a planetary field disruption or even a full reversal would have an effect on man-made circuits.
Good point of consideration though. We all should keep things like that in the back of our minds when thinking about the future.
In other news, I have located a turnkey GPS systen that can log over 3000 positions in its mem module (can be enhanced via OEM) but it is quoted as only being able to get a location update every 1.5 seconds. Its price is near what I expected (1599.00 USD) but I still need a way of transmitting that data to a ground station.
...in tiny steps, diligently, the miles do come.