3GS map service inaccurate

Using an iPhone 3GS with iOS 6.1.6. The location services provides inaccurate map location (the same results, regardless of the map app used). The blue indicator will have me in the same general area but may have me on a body of water or mountain when it should have my location on a road/street. The blue indicator does not flow with travel. It seems to remain stationary, then periodically leap to a new stationary position. I suspect that it locates the closest tower and conveys the tower's location. This iPhone was a replacement, purchased at an APPLE store about 1.5-2 years ago. Suggestions are appreciated.3GS map service inaccurate