GPS Antenna Direction

[rcompart]

Does anyone know if the GPS antenna must face a certain direction? I just bought a Caliber and it has two mounting screw holes where the GPS antenna is supposed to go but it is laid out like this where the O's are the mounting screws and the X is the GPS antenna and the -- is the cable coming out. Ignore the periods as they are only used to correct spacing.

...O
--X
...O

The bracket looks like it is supposed to be installed like this

O X O
...I



Will my GPS function right if I install it like that. Does it use the built in compass to determine actual direction or is it part of the GPS antenna?

Thanks

BTW, if you have that bracket from a GPS antenna and it will work, I have one from a L-shaped one from a jeep so I need a flat one.

[Jaak]

It doesn't care as long as the whole thing faces up. It has no concept of direction, it calculates where you are by the time it takes for each satellite's signal to travel to the receiver. Since it knows what the orbits are for each, it's a simple matter of math and a precise time base.

[linuxkidd]

And, it calculates the direction of travel by looking at the direction between 2 consecutive location measurements.

LK

[Jaak]

Yup, which is why sometimes GPS systems that have no compass built in, fluctuate in which direction they think you're facing. Staying still brings in to play measurement and system inserted errors. As the GPS thinks you've moved slightly one way or another it figures you're heading in that direction. Another way to overcome that is to not change direction until you see a distance change greater than a certain amount. Obviously a location change of one foot to the right or left, doesn't mean you picked up the car and turned it that direction!

[rcompart]

Any one have a new one I can buy?