Hi, What would be best technology (GPS,IR,Radio/freq,ultrasonic etc) for doing distance measurements upto 10km with accuracy of 1 meter? GPS could be good for greater distance but accuracy seems coarse. - Surinder
measuring 10 km with 1m accuracy
Started by ●February 15, 2010
Reply by ●February 15, 20102010-02-15
Surinder Singh <gogreenmiles@gmail.com> wibbled on Monday 15 February 2010 12:13> Hi, > > What would be best technology (GPS,IR,Radio/freq,ultrasonic etc) for > doing distance measurements upto 10km with accuracy of 1 meter? > > GPS could be good for greater distance but accuracy seems coarse. > > - SurinderLaser I would have thought - eg google for Laser Total Station (an electronic theodolite with laser rangefinder). I'm not sure if those can do 10km in one go but some of the Leica machines with high powered lasers can do fair distances... It might help if you said what the application was eg surveying (ie operator based stationary measurements), unattended, moving targets, moving measuring station? -- Tim Watts Managers, politicians and environmentalists: Nature's carbon buffer.
Reply by ●February 15, 20102010-02-15
On Mon, 15 Feb 2010 04:13:09 -0800 (PST), Surinder Singh <gogreenmiles@gmail.com> wrote:>Hi, > >What would be best technology (GPS,IR,Radio/freq,ultrasonic etc) for >doing distance measurements upto 10km with accuracy of 1 meter?There are survey grade GPS units with centimeter accuracy. And, of course, there is also the traditional method using theodolites. It all depends on how you define "best." -- Rich Webb Norfolk, VA
Reply by ●February 15, 20102010-02-15
Surinder Singh wrote:> Hi, > > What would be best technology (GPS,IR,Radio/freq,ultrasonic etc) for > doing distance measurements upto 10km with accuracy of 1 meter? > > GPS could be good for greater distance but accuracy seems coarse. > > - SurinderIf you are not in a hurry, GPS using the geodetic methods will give accuracies well under a meter with static relative measurement. The needed measurement time will be about an hour, simultaneously at both ends of the measurement distance. With top-end geodetic receivers and sufficient measurement time, an accuracy of a centimeter or less is attainable. The position is the phase centerpoint of the antenna. -- Tauno Voipio tauno voipio (at) iki fi
Reply by ●February 15, 20102010-02-15
Surinder Singh wrote:> Hi, > > What would be best technology (GPS,IR,Radio/freq,ultrasonic etc) for > doing distance measurements upto 10km with accuracy of 1 meter?Measure 10km of what? The purpose of this measurement is what?> GPS could be good for greater distance but accuracy seems coarse.Use a long enough measuring tape. VLV
Reply by ●February 15, 20102010-02-15
Tauno Voipio wrote:> If you are not in a hurry, GPS using the geodetic methods will > give accuracies well under a meter with static relative measurement. > The needed measurement time will be about an hour, simultaneously > at both ends of the measurement distance. > > With top-end geodetic receivers and sufficient measurement time, > an accuracy of a centimeter or less is attainable. The position > is the phase centerpoint of the antenna.While ago I did a plot of a common GPS module readings taken at every second. The distribution was clearly not Gaussian; it was asymmetrical and skewed. I am not sure if it would be possible to improve the accuracy by averaging and how much of averaging it would take. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●February 15, 20102010-02-15
Vladimir Vassilevsky wrote:> Use a long enough measuring tape.I guess it would be difficult to get 1 m accuracy with a 10 km measuring tape (non-planar ground, tape stretching etc.). -- Frank Buss, fb@frank-buss.de http://www.frank-buss.de, http://www.it4-systems.de
Reply by ●February 15, 20102010-02-15
"Surinder Singh" <gogreenmiles@gmail.com> wrote in message news:630d8cc3-abb4-49ae-9d98-730e2f257e32@a17g2000pre.googlegroups.com...> What would be best technology (GPS,IR,Radio/freq,ultrasonic etc) for > doing distance measurements upto 10km with accuracy of 1 meter? > GPS could be good for greater distance but accuracy seems coarse.The original baseline of the Ordnance Survey was measured with glass tubes laid end to end. Mind you, they had a team of squaddies to do it for them, a much better activity than coming off second best against an army of 3rd World peasants in Afghanistan.
Reply by ●February 15, 20102010-02-15
On Mon, 15 Feb 2010 16:32:51 +0100, Frank Buss <fb@frank-buss.de> wrote:>Vladimir Vassilevsky wrote: > >> Use a long enough measuring tape. > >I guess it would be difficult to get 1 m accuracy with a 10 km measuring >tape (non-planar ground, tape stretching etc.).It also depends on what one considers distance to be. Is it the straight cord between the points? Or the great circle distance? Or the measured ground distance? Or something else? There are statutory definitions for civil survey work but those aren't appropriate in all cases. Actually, I would have guessed that the difference between the arc length and chord would have been greater but imagination isn't always a good guide at these scales. Turns out that it's only about 1 mm over a 10 km arc, so probably not too significant in the OP's 1 m requirement. -- Rich Webb Norfolk, VA
Reply by ●February 15, 20102010-02-15
Vladimir Vassilevsky wrote:> > > Tauno Voipio wrote: > > >> If you are not in a hurry, GPS using the geodetic methods will >> give accuracies well under a meter with static relative measurement. >> The needed measurement time will be about an hour, simultaneously >> at both ends of the measurement distance. >> >> With top-end geodetic receivers and sufficient measurement time, >> an accuracy of a centimeter or less is attainable. The position >> is the phase centerpoint of the antenna. > > While ago I did a plot of a common GPS module readings taken at every > second. The distribution was clearly not Gaussian; it was asymmetrical > and skewed. I am not sure if it would be possible to improve the > accuracy by averaging and how much of averaging it would take. > > Vladimir Vassilevsky > DSP and Mixed Signal Design Consultant > http://www.abvolt.comThat's why I said 'static relative measurement'. It means that the skew will be about the same at both ends. To get geodetic quality measurements, the raw data has to be adjusted so that the points will be taken at the same time (and plenty of them). -- Tauno Voipio tauno voipio (at) iki fi
