Hi
I’m working on project to convert coordinates to actual names of locations, and the locations are about 1km for each other. Has somebody experience the last 2 to 3 digits of the latitudes and longitudes not to talk of COG changing all the time even when the GPS receiver is static.
The bad news to me is, all the coordinates of the various locations are the same except the last 2 to 3 digits and i was that this last 2 to 3 digits in each coordinates was fixed so that i can used them to differentiate the different locations in my codes. The GPS receiver has been running for a day with LEDs flashing @ 1Hz indicating lock has been archive. I’ve use about 5 different terminal; programs to view the NMEA message but the values all seems to changes irrespective of the number of satellites lock.
If i’m right, i guest the reason of the changing values in a static GPS receiver is because of the different satellites being track and out of track as can be seen in the radar view of the GPS program otherwise how can this be solved for me to accurately use the coordinates to designates their respective locations.
Any hint will help.
Thanks
The position is only accurate to within 5-10 meters. How is it fluctuating by? If you change the last 3 digits to 000 and then to 999 and map it out through Google and measure the distance it works out to be about 600 feet or so. Try mapping your high and low range and measuring it to see if it’s within tolerance.
Hi Wayne
Thanks for the reply and your idea. What i did before was to use Geo coding of GPS visualizer to get the coordinates of the places i’m interesting in; which is close to that of the GPS receiver when converted as shown below:
-33.9221473,18.444507
-33.9253434,18.4458625
-33.9271772,18.4645522
-33.9380373,18.4714723,
-33.9463772,18.4739184,
As can be seen, some of them are very close if not of the last 3 digits that makes them different and because the last three digits are fluctuating, i can’t relates differentiate some of them. The interesting thing is, by inspecting the coordinates values, the first five digits of both the lat and lon of each location are not the same and might never be the same and hardly fluctuates, which means using only both the first coordinates in my algorithm and neglecting the rest can accurate designate a particular location.
I’ll try and experiment for a week or more to see if the coordinates stays the same and always gives the right location.
But for interest sake why is the COD (direction) always changing irrespective of the GPS receiver being motionless and how can this be accurately use for navigation!!!
Regards.
Pauldesign:
But for interest sake why is the COD (direction) always changing irrespective of the GPS receiver being motionless and how can this be accurately use for navigation!!!
The GPS can be used for navigation with certain limitations. I’m a pilot, and have GPS navigation in my aircraft. It’s a reasonable instrument for telling you where you are (or more accurately, where you were a second or two ago), but a lousy instrument for telling you which direction you are traveling in. Any time you change direction, there is considerable lag for the GPS to compute your new direction of travel.
The slower the object is moving, the more trouble you’re going to have trying to figure out direction from it due to the noise in the position information. For a stationary object, trying to compute direction is probably not realistic since you’ll be computing direction vectors solely from position noise. The handheld GPS I use for hiking has this problem… if I stop walking, the direction pointer fluctuates randomly.
It all depends on what kind of application you’re trying to develop, but an accelerometer, gyro, or compass might give you more accurate information if you’re trying to measure direction, and not position.
Thanks a lot for the intuitive explanation which i must appreciate. Kudos!!! 