I often need to do range tests on short-range radio devices from 500 to at most about 25,000 feet separation. A clear line of sight for laser rangefinding is not always possible. Measuring the range using a GPS is simple enough; just set a waypoint at the fixed end, tell the GPS "navigate to that waypoint" then walk away with the other end of the link. However, is there an off-the-shelf GPS receiver that will show these sorts of distances *in feet*? Most handheld devices show a limited number of digits onscreen, so the accuracy drops as you move away: it will quote the range in feet up to perhaps 500 feet, then switch to fractions of a mile. While money isn't exactly an important factor, I'd like to keep it under US$1k. Thanks for any advice.
GPS for range testing radio devices?
Started by ●November 13, 2007
Reply by ●November 13, 20072007-11-13
Un bel giorno larwe digit�:> However, is there an off-the-shelf GPS receiver that will show these > sorts of distances *in feet*?IIRC one feet is about 0.3 m. Common GPS have absolute precisions around 2-3 m CEP. Therefore you need a *very* precise GPS, most probably a DGPS.> While money isn't exactly an important factor, I'd like to keep it > under US$1k.5 k$ are more likely. Something like this: http://www.trimble.com/geoxh.shtml -- emboliaschizoide.splinder.com
Reply by ●November 13, 20072007-11-13
On Nov 13, 5:38 pm, larwe <zwsdot...@gmail.com> wrote:> I often need to do range tests on short-range radio devices from 500 > to at most about 25,000 feet separation. A clear line of sight for > laser rangefinding is not always possible. Measuring the range using a > GPS is simple enough; just set a waypoint at the fixed end, tell the > GPS "navigate to that waypoint" then walk away with the other end of > the link. > > However, is there an off-the-shelf GPS receiver that will show these > sorts of distances *in feet*? > > Most handheld devices show a limited number of digits onscreen, so the > accuracy drops as you move away: it will quote the range in feet up to > perhaps 500 feet, then switch to fractions of a mile. > > While money isn't exactly an important factor, I'd like to keep it > under US$1k.I just tried my Garmin GPSmap 60Cx, and even though it shows the distance in miles, it can show 2 digits after the decimal point corresponding to 0.01 mile resolution (52.8 ft). If you don't mind metric, you can get 0.01 km resolution (32.8 ft)
Reply by ●November 13, 20072007-11-13
On Nov 13, 1:27 pm, dalai lamah <antonio12...@hotmail.com> wrote:> > While money isn't exactly an important factor, I'd like to keep it > > under US$1k. > > 5 k$ are more likely. Something like this: > > http://www.trimble.com/geoxh.shtmlThe resolution here is tighter than I need. 25ft accuracy would be acceptable.
Reply by ●November 13, 20072007-11-13
"larwe" <zwsdotcom@gmail.com> wrote in message news:1194971925.285906.240050@o80g2000hse.googlegroups.com...>I often need to do range tests on short-range radio devices from 500 > to at most about 25,000 feet separation. A clear line of sight for > laser rangefinding is not always possible. Measuring the range using a > GPS is simple enough; just set a waypoint at the fixed end, tell the > GPS "navigate to that waypoint" then walk away with the other end of > the link. > > However, is there an off-the-shelf GPS receiver that will show these > sorts of distances *in feet*? > > Most handheld devices show a limited number of digits onscreen, so the > accuracy drops as you move away: it will quote the range in feet up to > perhaps 500 feet, then switch to fractions of a mile. > > While money isn't exactly an important factor, I'd like to keep it > under US$1k. > > Thanks for any advice. >Not sure about off-the-shelf but if you're up for a bit of programming a PocketPC (iPAQ, of course) and a Bluetooth GPS would give you a platform for just about any custom GPS app. With the .NET Compact Framework you can use the CSerialPort class for fairly painless interfacing to the GPS. Andrew
Reply by ●November 13, 20072007-11-13
On Nov 13, 3:40 pm, "andrew queisser" <andrewdotqueis...@hp.com> wrote:> Not sure about off-the-shelf but if you're up for a bit of programming a > PocketPC (iPAQ, of course) and a Bluetooth GPS would give you a platformOh no, I don't have time for custom-developing something. Basically I just want to order it for the guys that mostly do the range testing (it's usually not me, just my products :). Besides, I don't do Microsoft.
Reply by ●November 13, 20072007-11-13
"larwe" <zwsdotcom@gmail.com> wrote in message news:1194988143.928880.267810@k79g2000hse.googlegroups.com...> On Nov 13, 3:40 pm, "andrew queisser" <andrewdotqueis...@hp.com> > wrote: > >> Not sure about off-the-shelf but if you're up for a bit of programming a >> PocketPC (iPAQ, of course) and a Bluetooth GPS would give you a platform > > Oh no, I don't have time for custom-developing something. Basically I > just want to order it for the guys that mostly do the range testing > (it's usually not me, just my products :). Besides, I don't do > Microsoft. >Ahh, I thought that might be the case. Well, there might be a niche there for someone then. I was going to mention that you can install Linux on iPAQs and other PocketPCs but it's even fiddlier but ultimately more rewarding. Andrew
Reply by ●November 13, 20072007-11-13
"dalai lamah" <antonio12358@hotmail.com> wrote in message news:kvri5bt0iahd$.107pewx6ejdra.dlg@40tude.net...> Un bel giorno larwe digit�: > >> However, is there an off-the-shelf GPS receiver that will show these >> sorts of distances *in feet*? > > IIRC one feet is about 0.3 m. Common GPS have absolute precisions around > 2-3 m CEP. Therefore you need a *very* precise GPS, most probably a DGPS. > >> While money isn't exactly an important factor, I'd like to keep it >> under US$1k. > > 5 k$ are more likely. Something like this: > > http://www.trimble.com/geoxh.shtml > > -- > emboliaschizoide.splinder.comAbout any GPS has a serial output in NMEA 183 format at 4800 baud. Feed that serial stream to your link and receive it at the other end. using another identical GPS unit to compare with, you have DGPS! Take the difference in position to get range. Quite accurate over the range you are talking about. Don
Reply by ●November 13, 20072007-11-13
On 2007-11-13, Donald Harris <harrisdw1@verizon.net> wrote:>>> However, is there an off-the-shelf GPS receiver that will show these >>> sorts of distances *in feet*?> About any GPS has a serial output in NMEA 183 format at 4800 > baud. Feed that serial stream to your link and receive it at > the other end. using another identical GPS unit to compare > with, you have DGPS! Take the difference in position to get > range. Quite accurate over the range you are talking about.Except that "taking the difference in position" isn't trivial. There might be a way to use maps.google.com or some other bit cartography package, but writing and debugging a program to compute line-of-site distances between two points on the surface of the geoid is icky. -- Grant Edwards grante Yow! Awright, which one of at you hid my PENIS ENVY? visi.com
Reply by ●November 13, 20072007-11-13
In comp.arch.embedded, Grant Edwards <grante@visi.com> wrote:> On 2007-11-13, Donald Harris <harrisdw1@verizon.net> wrote: > >>>> However, is there an off-the-shelf GPS receiver that will show these >>>> sorts of distances *in feet*? > >> About any GPS has a serial output in NMEA 183 format at 4800 >> baud. Feed that serial stream to your link and receive it at >> the other end. using another identical GPS unit to compare >> with, you have DGPS! Take the difference in position to get >> range. Quite accurate over the range you are talking about. > > Except that "taking the difference in position" isn't trivial. > There might be a way to use maps.google.com or some other bit > cartography package, but writing and debugging a program to > compute line-of-site distances between two points on the > surface of the geoid is icky.Calculating the "great circle" distance is fairly easy and possibly accurate enough for your needs. See for instance: http://www.movable-type.co.uk/scripts/latlong.html (Look for the spherical law) If this is not accurate enough, click through to the Vincenty page, but that indeed gets more tricky. ;-) -- Stef (remove caps, dashes and .invalid from e-mail address to reply by mail)
