handheld GPS

[Sacamuelas]

Any preferences on these units? Features that are mandatory? Brands that are found to be more rugid in the field?

I personally have a Garmin GPSmap 76S. Fantastic little unit and has a built in electronic compass for getting a bearing even while stationary.

[GreenSalsa]

E-Trex....So many useful functions, so easy to use, extremely rugged, small, light weight, uses AA batteries, and best of all has an interface system that allows me to upload all the waypoints I want from my laptop. I line up the detachments GPS, sync them all, and in 15 min I have EVERYONES uploaded.

Thats my opinion...

[Sacamuelas]

GS-
Those are the same things I like about my 76S. It has 24 mb of memory to upload topo/other maps, has an easy to use PC linkup, and uses two AA batteries. The Garmin software allows you to plot your course/waypoints on your laptop and then upload it onto the GPS unit.

[Psywar1-0]

Being from the "Back when it was somewhat inconvient" days Ive only recently started using GPS's. Used an Etrex Vista for a short time, then went to the Rhino 120 since I was carrying both a GPS and a FRS and this combined both. Anyway have used them thruout my little part of Latin America and had no major problems. Little problem with the Rhino is that it locks up after 10-12 hours of solid use, or starts telling me im in China. Also while operating on the coast, both units reported 8 meter accuracy but showed I was in the water when I was 25 meters at least up on land. Thats why you cant use Civ GPS's for things like Call for Fire!

[37F5V]

I thought that the Selective availability went the way of the Dodo a few years back?

I've had great experiences with my Etrex.... Super easy to use and once it has a lock it holds it quite well..

JT

[Sacamuelas]

Is your GPS a WAAS capable unti? If so, can you receive the WAAS signal when SOTB? I know there are satellites over the Atlantic and the Pacific but the system is "incomplete".

My unit gets to 1-3m accuracy (legit and confirmed) everywhere I have been in the US. That takes at least four satellites of the 12 possible recieving the WAAS differential info. Can you get that type of satellite access in South/Central Americas?

[18C4V]

Etrex Vista....issue item on my team. Works great.......easy to sync waypoints like GS said. Any JM's out there use the JM program yet? If so, how is it?

[Psywar1-0]

Im usually only able to get 3 sats at most, many times only 2d accuracy while on the coast. Tried changing from WGS 84 to other Surveys specific to my location and same thing.

As far as the JM program, I played arround with it both on the ground and in the air, but never jumped. According to the Crew Chief/Loadmaster where the GPS said to jump was pretty much in line with where they put troops out on one specific DZ.

[Team Sergeant]

Originally posted by Psywar1-0
Thats why you cant use Civ GPS's for things like Call for Fire!

Yes you can....

You do realize slick willy told the DoD to "descramble" the GPS signals in 2000?

A good civilian unit now has a 20-40 foot accuracy. If the GPS is WAAS enabled it is accurate to about 9 feet.

There's a good write up in this months "Scientific American".

Team Sergeant

[The Reaper]

Garmin showed a great looking wrist mounted model at the SHOT.

Maybe 1.5"x2.5"x.75", screen large enough to be useful, looked like a nice piece of kit.

I have the brochure at the house somewhere, if anyone is interested.

TR

[Razor]

Even with Selective Availability turned off, there is still the problem of ionospheric interference, which can affect the accuracy of the solution. As it currently stands, both civ units and the PSN-11 PLGR are single channel units, so they use a 'best guess' model to take interference into account in their respective algorithms. Once the dual-channel DAGR (Defense Advanced GPS Receiver) is fielded, however, it will provided a much greater degree of accuracy than civ units will be capable of providing.

One advantage of using a PLGR is its compatibility with the Viper laser rangefinder for quickly finding the position and elevation of a distant point, which comes in handy while calling for fire or CAS. AFAIK, no civ receiver is currently compatible with the Viper. The keypad on the PLGR is also useful for quickly entering grids or performing conversions; most civ receivers use a scrolling menu/entry method for data entry.

The WAAS (Wide Area Augmentation System) does indeed add several degrees of accuracy, however its unlikely our soldiers will need to call for fire in the US, Canada or Mexico anytime soon (the only place WAAS is currently established is North America). One method of overcoming the problem of ionospheric interference, low signal strength and the lack of WAAS is through the use of manually emplaced pseudolites or other antennas/repeaters in an AOR. We'll just have to wait and see how this concept develops.

The good news is that the degree of error one usually gets when using a civ receiver (1 to 15 meters) is often moot when requesting scunion on the bad guys, unless you're trying to put a PGM through a window. Regardless of the advances of technology, a 2000lb HE 'dumb bomb' can still get someone's attention rather quickly.