Here is a product developed for use in a hostile environment. The GPS can be left in a position where it may be exposed to dust or water, and it will continue to transmit the GPS position using a long range Bluetooth device. You can use the GPS position signal, in any Bluetooth computing device, such as a laptop with mapping or data logging software.
Price for a complete system as shown is $1204 including GST. Available from Johnny Appleseed GPS Ph 1800 666477

The system has been tested for Bluetooth transmission to well over 100 metres, and with the battery supplied, will run for around 10 hours. It utilizes a GPS35 Tracpac and a long range Bluetooth converter. A 240 volt charger can charge the battery either inside, or removed from, the case. The case is a standard Otter product, Model 3500, overall dimensions are 220mm x 130mm x 50mm. It includes a lanyard. Various ways of mounting this GPS can be devised, including RAM mounts to suit your purpose.

The GARMIN GPS35 TracPak