You have to use a Blue Tooth solution inside a building to get accurate position.
On 2012-1-9, at 上午3:05, BJ Freeman wrote: > GPS Differential Beacon Signal (DGPS) receivers deliver positions > accurate to within 10 meters, and potentially to 1 meter. > these rebroacast in a building gives fairly accurate measurements. > > David Legg sent the following on 1/8/2012 10:42 AM: >> When I do surveys for OpenStreetmap.org I take my GPS unit outside and >> traverse the street/path/road etc in both directions to get a good >> average set of nodes. On a good day here in the UK I can get the >> accuracy down to a few feet using a Garmin eTrex Vista HCx. But that's >> only after letting the unit track all available satellites for a minute >> or two. >> >> Getting sufficient signal inside a multi-story building is pretty >> difficult. >> >> I've started testing a Samsung Galaxy Tablet and using Google maps to >> show where you are causes your position to jump about as the unit flips >> between the different methods of locating your position. >> >> >> On 08/01/12 17:57, BJ Freeman wrote: >>> how do you explain surveying with gps? >>> >>> David Legg sent the following on 1/8/2012 9:21 AM: >>>> Nice idea but I don't think this would work very well unless you were >>>> eating alfresco! >>>> >>>> GPS signals don't penetrate buildings very well and triangulation using >>>> cell tower signals would mean you would have to place each table several >>>> hundred yards apart! >>>> >>>> David Legg >>>> >>>> On 08/01/12 16:34, BJ Freeman wrote: >>>>> using 10.2 tablets, customer can order and pay for meals. >>>>> with the GPS built in position in the restaurant can be determine and >>>>> translated to table an place at the table. >>>>> the staff have to be trained to put the tables in preconfigured places >>>>> and ways. >>>>> the payment allows for spiting the bill and manually Entering the CC >>>>> info for each that is paying or use the attached card swipe. >>>>> >>>>> >>>> >>> >> >> >
