How to improve position accuracy of recorded points
July 2, 2013 Leave a comment
When using a consumer-grade GPS, you may find that the device does not pin-point your exact location. Sometimes the GPS marker can be quite a distance away from your actual position.
As we’ve mentioned in a previous post, there are many factors that affect the accuracy of the computed GPS position. Some of those factors are out of your control. GPS differential correction can help remove some sources of position errors, but consumer-grade GPS does not provide differentially corrected GPS data.
Nevertheless, you can do a few things to help improve the position accuracy of the points logged. First of all, make sure your device has a good view of the sky and is not obstructed by nearby objects (especially reflective ones) or buildings. Secondly, after turning on the GPS device, wait 8 – 10 minutes until it settles down. This will be indicated by the GPS marker settling close to where it should be (if you are doing this at a reference location) and is not jumping all around. Then you would start recording your point positions. If you are using iCMTGIS II or iGPS GIS II, you can usually get a reasonably good position by setting the Time Session to 300 seconds (5 minutes).
Remember that each time you turn GPS off from your app and turn it back on, you will need to wait a few minutes for the GPS to settle down. Same if you turn off an external GPS device then turn it on using its ON button.