GPS in non-mobile environment

is there any app that could be used for GPS in a non-mobile network area?

Is there a way a Garmin GPS unit could be linked to an iPad in order to track movement and create notes/waypoints as you progress? Bigger screen and ability to annotate will increase productivity and alleviate ever shortening of the arms with age.

We are working in north east Ethiopia and such an ability would make life so much easier. Unfortunately no network coverage as this is really quite a third world (minus) area and development initiatives have other priorities.

There is, but it involves Jailbreaking (because apple does not allow any external GPS units) and then using it with a supported GPS device (Which is almost any GPS that can send it's RAW GPS data to other devices via bluetooth)
roqyBluetooth

I use it with great success on my iPod Touch, but I'm not sure it a Garmin device would work as I don't think they have Bluetooth capabilities.