Today's GPS receivers are extremely accurate thanks to their parallel multi-channel design. Garmin GPS receivers are accurate to within 15 meters (49 feet) 95% of the time with a clear view of the sky. Generally, users will see accuracy within 5 to 10 meters (16 to 33 feet) under normal conditions.
Certain atmospheric factors and other sources of error can affect the accuracy of GPS receivers. From time to time your accuracy will drop. GPS works on 'line of sight'. If the device does not have a clear view of the sky your accuracy will drop and sometimes you will lose reception altogether. This is because the GPS signal is not powerful enough to travel through most solid objects. This holds true for all GPS devices.
To ensure you receive the best accuracy possible:
- Avoid storing the device in your pocket, backpack, or rucksack
- Ensure you hold your device properly as its antenna is located with this expectation
- If possible, navigate to an area with a clear view of the sky
Following the above steps will increase your chances of a good, strong and accurate GPS signal lock. Remember, a GPS receiver is a complement to navigation and should not be the only navigational tool that you use. Using a paper map, a simple compass, and having knowledge of manual navigation is a good, safe practice. GPS should be utilized as a guide, not as the absolute definition of what happened. This applies to any device that is not a professional survey tool.