its a hummer just wing it, especially if you go offroad,

thank you gm for a good nav system

 

It's the way GPS works and likely your antenna is the problem. What happens is there are satellites that all transmit time coded messages the receiver interprets and knowing each of the satellites position tries to align such that the drift between each aligns up at a point in time which is used to derive the distance ratios. Once those ratios are computed you can then determine the position on the earth down to the accuracy of the clock on the receiver. The problem comes in with the fewer satellites you can receive your accuracy plummets. You could have bad map data but likely you just have a bad antenna.

 

Where are you buy a fake GPS,the qulity so terrible.I ever buy the GPS form the oemcargps shop ,the qulity is better than other shop and the prcie is reasonable. In the website teching us how to install the GPS step by step.

 

I agree with you ,the Apple iPhone wireless phone models G3, G3S and 4.0 all have built-in global positioning systems (GPS). With the iPhone 4.0, the GPS system provides directions, traffic reports and a compass.