I just starting to do some research in getting a inexpensive handheld GPS unit. Years past here in rmr there have been numerous recommendations for GPS units that have been used for rocketry purposes. I'm not looking for flying a GPS, just a handheld unit that could also work well with following a straight line to the landed rocket.
"Inexpensive" and "GPS" don't go together well. GPSes have started becoming commodity items, so the GPS makers are bundling maps, navigation, color displays and such stuff with/in the GPSes now to differentiate themselves and make a product that can sell with a profit margin. A low-end lat/lon+trail GPS doesn't cost much more than the Oncore module itself does.
The Garmin Vista is the only GPS I know of that has the "line following" feature. It includes a built-in compass (a magnetic one, as opposed to using the GPS satellites to calculate 'north').
I have a Garmin Legend (the old B&W one) and it has base maps, waypoints, and all that fun stuff, but it doesn't have the compass. If you're going to use the GPS for other things, like travelling, a GPS with an external antenna connector - and an external amplified antenna - will make using it in the car a lot nicer.
I have two Garmin units and both have the built-in magnetic compass: Etrex Summit and Etrex Vista. With the Sight-N-Go feature you can point the unit in the direction you want to go and lock in a course. It even has a couple of sighting marks on the top to help. It works quite well although you have to realize that the resolution and accuracy of the compass are limited. Do not expect it to bring you directly on top of your rocket but it will get you close.
The Summit doesn't have the mapping features of the Vista. I download a USGS map of the area I will be flying into the Vista from the Mapsource CD. This helps me to decide if I should get in my car or just start walking. If there is a handy crossroad along the path and it looks to be a long walk, I take the car.
The manuals for these units are available online at the Garmin web site. Look at them and decide if you like what you see.
The feature is called SiteNGo by Garmin. It's on the Summit and the Vista. The summit has no base map, the Vista knows interstates, major roads, cities, etc, plus what's at interstate exits. It also has the ability to download additional stuff into it. There's also a larger Map76S (I think that's the right model) that's about the same features as the Vista but physically larger. And now there are color models for even more $$$.
You can use the base eTrex (under $100) to find rockets if you manually mark four points and two lines of sight. The Summit and Vista can do it from one place.
Note that a GPS can calculate location, but NOT direction. It has no idea which way it's facing. It can compute that when it's moving, but not when stationary. Thus the need for the magnetic compass for the SiteNGo feature.
Sorry Bob, I ment to "reply to group" Well group here is what I sent to Bob.
I saw someone at airfest use the Rhino 110 with the FRS, in the rocket, and had another one to track with. He said that as long as he got a reading, in the air from the on board unit, while it was in range of the one he was holding, the one he was holding showed where the other one was. Then he just had to go to the area of the last reading, at this time if the two units shold be in range of each other again, then he could "ask" where are you!, some kind of neighbor command built into the Rhino, and it would respond with directions to the one he was holding. I am a little unclear on the commands, and how they were used, as I only got a percursary explanation. My understanding that this "sharing" is done by the FRS radio function. I also heard this is also used by hunters to make sure where each person of the hunting party knows where the others are for safety reasons. I do not recall who did the flight, but understand he found his rocket about 2.5 miles away, after abou a 23,000 ft flight! Mike Dickinson
More fun to put a GPS tracker on you Teen-age kid's car. Yes, they do exist. You can put together a GPS + 900MHz radio pretty cheaply. There are off the shelf units that sell for a few hundred dollars (plus another few for a receiver). Using APRS with a 2M radio lets you take advantage of all the infrastructure for tracking APRS packets.
Yes, they exist. And so do full-bosomed, curvaceous Vulcan women who would really, really love it if you'd give them a full body rubdown with an anti-bacterial gel, while sitting nude in a hot, steamy quarantine chamber.
Cuz, you know, that was on TV. And as everyone knows, IF IT WAS ON TV OR IN A MOVIE, THEN IT'S GOT TO BE REAL!!!!
free, but very reasonably priced. I can download Topo maps and aerial photos from their website and then hook it up to my GPS in the field to map out my location in real-time. I've used this with my homemade GPS tracker to display the rocket's track also. You can then download the location into your handheld unit. For testing I've merged waypoint taken with the handheld with ones taken from the rocket to see how close they are. Within 6-12 ft in most cases.
for converting GPS data into a Google map.
Unfortunately the only maps that can be uploaded to a Garmin are Garmin maps.
You know, "Mythbusters" just did a thing on Mission-impossible style break-ins. They tried to find one of those intrusion alarms where visible laser beams crisscross the room and discovered they didn't exist.
I guess they'd been shown so often almost everyone believed in them.
My homemade tracker sends NMEA sentences which GPSexpert can understand. I've used it two ways, live and replay. In replay I import a file containing the NMEA sentences captured during a flight. I need to write come code in my base station to periodically insert a waypoint so I can feed it directly to my Garmin.