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.
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
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.
Bob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)! <<<
Kaplow Klips & Baffle: http://nira-rocketry.org/Document/MayJun00.pdf
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!
Looks like the eTrax Vista might be the correct GPS for me. A quick
check at Target shows they have it for $150, which is within my budget.
I'm sure I can do better with some searching.
I'll be using it for rocket retrieval but I would also like to use it
for other purposes as well. When I get a big ticket item(for me at
least) I like to get multiple uses out of it.
Will the Vista work with google maps?
I kept hearing that you could import google maps into some GPS units. I
guess I must've heard wrong then ;/ My plan for the GPS was to use it
for rocketry but also use it for fishing up north.
I've been very happy with ExpertGPS http://expertgps.com/default.asp
Not 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.
I found http://www.gpsvisualizer.com/ for converting GPS data into a
Unfortunately the only maps that can be uploaded to a Garmin are Garmin
I have a Garmin Vista. Several years old.
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.
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.
David W. Schultz
Do they sell any GPS tracking devices that are small enough to fit inside a
rocket (or some coat pocket for that matter)?
That could make theft very difficult if you can fit your valuables with a
"tdstr" < firstname.lastname@example.org> wrote in message
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
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!!!!
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
I guess they'd been shown so often almost everyone believed in them.
I have the regular yellow Garmin Etrex. It does not have the site 'n go
feature that the Vista does. But it does work.
I've used it to track rockets, and it works well. I punch in a compass
heading derived from a handheld magnetic compass, punch in how far away I
think it landed, (I usually use a mile or two) and go.
The process is subject to user error, and is not fool-proof. It depends on
how good of a 'bead' you got on the rocket when it came down, and how steady
and accurate with the compass you are.
It is most effective with used in conjunction with a loud beeper. The GPS
will usually get you close enough to hear the beeper.
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