Improving the Track Distance Accuracy of an inReach Handheld

The GPS receivers used in the inReach SE®+, inReach Explorer®+, and inReach® Mini handhelds are accurate to within 15 meters (49 feet) 95% of the time. Generally, users will see accuracy within 5 to 10 meters (16 to 33 feet) under normal conditions, with up to date firmware. To update your firmware, refer to the following articles:

• Updating the Firmware and Syncing Account Information to an inReach SE+/Explorer+
• Updating the Firmware and Syncing Account Information to an inReach Mini

If the firmware is already up to date, there are other factors that can still affect the accuracy of position, distance, and speed readings, and steps that can be taken to prevent or minimize factors that decrease accuracy.

Why Is My Track Distance Inaccurate?

There are two main factors to consider when troubleshooting distance readings:

• Log interval settings
• Weak satellite signal

Lower log interval settings can be beneficial for increasing battery life, but will reduce the detail of recorded tracks and can result in a shorter total distance reading. A weaker satellite signal, which may decrease position accuracy, affecting the overall accuracy of the distance and speed readings.

How Log Interval Settings Affect Distance Accuracy

The log interval setting on inReach handhelds determines how often the inReach records your GPS position. Each point recorded is saved to the inReach and the recorded points are connected by lines to create a track. 

For example, a track that has been recorded with a 1 second log interval will have greater detail and distance accuracy when compared to a track that has been recorded with a 1 minute log interval (the default setting). Reducing the frequency of the log interval will result in longer battery life, but less accuracy. Increasing the frequency of the log interval will result in higher accuracy, but shorter battery life.

In the example below you can see that 1 second recording creates a more smooth track line, and picks up small changes that the 5 minute log interval does not.

For more details on log interval and how to adjust this setting, see Related.

Weak Satellite Signal Due to Environmental Factors

Any outside influence on the accuracy of the handheld is an environmental factor and can cause a degraded GPS signal. Environmental factors can range from using GPS downtown in a major city to trying to record a hike under a dense tree canopy. Using the handheld to record GPS in those types of environments blocks the handheld's ability to directly receive a GPS signal. You can think of environmental factors as things that interrupt the signal path of a GPS satellite to the handheld.

The first step to recording accurate GPS data is to reduce distortion and degradation caused by environmental factors. GPS works best when there are no obstructions above 15 degrees over the horizon. Avoid the following when recording tracks, if possible:

• Tall buildings
• Dense forest or canopy
• Canyons
• Using GPS in a dense group of people
• Using GPS indoors