GPS Tips and Best Practices

Dodgy looking data?

Your GPS device may not always record location data in a way that accurately represents your session on the water. Bad GPS data can result in your trips having missing or extra distance recorded or recorded inaccurately. This can happen because:

• Your device may have simply lost a connection to GPS satellites and did not record any data. 
• Your device may have recorded GPS points that deviate from your true path.

We have a number of processes which resolve most cases of inaccurate data. However, we are only able to  make the most out of the data provided to us from the GPS device. Therefore, if you experience a low GPS connection at some point during your trip which results in the recording of bad data, or in some cases no recording at all, your trip details will unfortunately appear inaccurate as Paddle Logger is unable to correct bad GPS data nor fill in missing data. 

What causes poor quality GPS data?

There are many factors that contribute to the quality (accuracy and precision) of your GPS data - and it's important to keep in mind that no data is perfect. Every GPS - enabled device will have some degree of error, whether that is your iPhone, Apple Watch, Garmin or other piece of hardware. Ignoring (for now) environmental factors, these different devices simply have different qualities of GPS hardware - meaning that even if your device is working at its peak performance, there will always be a margin of error in the accuracy of its recording. There are apps out there that will assess your device's capability, and Paddle Logger also has a GPS strength indicator - based on how close your device is operating to it’s peak performance.

GPS works by connecting your device to a number of overhead satellites and very precisely measuring the amount of time it takes for a signal to travel between your device and the satellites. Because the speed at which the signal travels is known, the amount of time the signal is in transit allows your device to calculate the distance to each satellite. Since the position of each satellite is known, as well as the distance between those satellites and your GPS device, your position can be calculated.

Slight inaccuracies in the signal's reception, or disturbance to the signal itself, can potentially translate to a significant dislocation of your reported position. This is why environmental factors such as dense trees, steep cliffs, tall buildings, or even heavy cloud cover can impact or even interrupt the travel of a GPS signal.

Improving data quality

Thankfully, there is more that can be done to prevent bad GPS data from being recorded than there is to repair it. Different devices do simply have different qualities of GPS hardware, so although there are some tips and tricks that are device-specific, there are also some key practices that can help improve your GPS data quality regardless of what device you're using.

• Make sure your device is mounted/carried as high up and unobstructed as possible, instead of buried deep in a pocket or bag.
  • Your choice of case will have an impact on the quality of data your device can record - a thin waterproof case/bag may be better than a thick rubber bumper style.
• Do your best to avoid environments that are always going to be problematic for a GPS signal whether natural or man-made such as in the vicinity of tall buildings, dense trees, equally, being under tall cliffs may have a similar impact
• In many cases it will help to give your device a minute or two to fully acquire a signal before starting a paddle; and doing so outside, rather than inside while you get ready, will be beneficial. 
  • If you’re experiencing GPS inaccuracy, we’d recommend either setting the countdown timer for at least one minute, or have the paddling screen open for at least one minute before starting your paddle.
• Sometimes simply turning your device off and on again, or disabling and enabling GPS, may also improve the quality of data.

If you are interested further in how different devices measure data differently and what you can do to improve it, this detailed testing from a Runner provides a great insight into GPS Accuracy.