I have always said that a NavStar Global Positioning System (GPS) receiver is an outstanding tool for use in CAP Emergency Services missions.   Always wanting to put my money where my mouth is, I purchased one a number of years ago.   I came to several conclusions after considerable experimentation.  

A GPS unit is a tool for someone who is already proficient with a map and compass.   If you can't navigate "the old fashioned way," you have no business performing ES operations.   Machines fail, batteries die, and signals can be hard to receive.   Know the basics before you try advanced things.

Prior to owning a GPS receiver, I've had ample opportunity to borrow units from work, other CAP members, or CAP-owned equipment.   On several occasions this equipment was loaned to me at the last minute.   It is not a good time to learn to operate a GPS receiver just as you are leaving mission base.   I've had my team members become enamored with GPS magic and fail to pay attention to anything else--they sit there and play with the toy instead of minding the mission.   Some gentle reminding will get these folks back in the game.   The end result in these cases is that the GPS receiver becomes a hindrance rather than a useful tool.   You can spend all their time learning how to operate the GPS, or you can use your map and compass to get the job done.   I've also had similar experiences in the aircraft with GPS and LORAN equipment.   Rather than pay attention to conventional NAVAIDs, I've had both mission pilots and observers attempt to figure out the LORAN.   Again, it can be a useful tool, or you can become a slave to the machine.   The moral is that you need to know how to operate the GPS (to a good level of proficiency) if you are going to use it.   Otherwise rely on your tried-and-true methods.

A GPS unit can reduce your dependency on the need for a map.   Saying that worries me that I mean you don't need a map when you go into the field or climb into the airplane--that is not the case.   A map is one of your most basic and essential tools.   In a pinch, however, you might be able to get by without one for a brief period of time.   This is because many GPS units will "make" a map for you--a plotting of your track as you progress.   If you name waypoints, like your mission base, then you have references with which you can return.  

Extremely proficient users of their GPS may even be able to use it to triangulate a fix during an electronic search.   When you are in location B1 (where you take your first bearing), have the GPS plot the bearing to the signal.   Repeat this from another location (at least once).   Create a new waypoint where the vectors cross.   Under ideal conditions, that will be the location of the ELT.   Any electronic searcher will know how to do this method on a map, but only advanced navigators can do it directly on their GPS.   It would be foolish not to back yourself up on your map, however.  

Relying solely on a GPS for navigation breaks down quickly, however, with the slightest hint of operator error, bad equipment, or poor GPS coverage.   Furthermore, even all those things work perfectly, you may not get to the target in the most rapid means available.   Pilots may fly through special use airspace and ground teams will not know the availability of roads to the location.  

Ultimately the point is that a GPS unit can give you such a high situational awareness that you may find that you're using it as your primary reference in navigation.   I think this is acceptable--as long as you can back yourself up by other means.

It is said elsewhere in this site that aircrews should be familiar in utilizing their GPS or LORAN for aiding them in a grid search.   Ground teams should be equally familiar in using a GPS unit to aid them in an area search as well.   In addition to tried-and-true methods such as flagging, a ground team navigator can mark positions in his or her GPS unit and search in relation to that point.  

These words are intended to stimulate discussion and training practices.   It is hoped that objective was achieved.   I would sincerely appreciate contributions of your GPS experiences, especially SSTV or APRS issues.