Mountain Canine Corps

MC²

Search and Rescue Team

Short GPS exercise

For this exercise, you will need a working GPS, pen, paper, and a topographic map of the area with an overlaid grid of UTM coordinates. Also, the datum of the map should be NAD 27.

Caution: Some weather conditions and/or heavy vegetation can cause difficulty in receiving a GPS signal and you should always maintain awareness of your location. Also, most GPS units use batteries relatively quickly and you should carry plenty of spare batteries.

Action	Hints and questions
1. With your GPS using the NAD 27 datum, save a waypoint at your house.	Before setting a waypoint or giving your coordinates, make sure your GPS has good accuracy by checking the satellite reception page.
2. Go for a walk and watch the coordinates change (and watch your step).
3. Stop and save a new waypoint.	Find your current waypoint's coordinates on the map. Is the location correct? If not, how is the satellite reception? Is your GPS system set to the same datum as your map?
4. Recall your house's waypoint and write down the coordinates.
5. Change to the WGS 84 datum.	Where are you on the NAD 27 map now?
6. Recall your house's waypoint again and compare the coordinates with the coordinates you wrote in number 4.	Did the coordinates change? How different are the coordinates- in what direction and by how far?
7. Change to latitude-longitude format.
8. Recall your house's waypoint again and turn on navigation to that point.	Are the coordinates showing in lat-long format? Is the heading your GPS signifies to your house correct? Caution: Unless your GPS shows direction with respect to north or has an electronic (usually optional feature) compass, the direction of travel will often be wrong unless you are moving. According to the GPS, how far away is your house?
9. Look at your track from your house and follow your path backwards.