Great Smoky Mountains National Park does not provide any characterization on the accuracy or precision on commercial, consumer-grade hand-held GPS equipment or GPS-enabled mobile devices such as smart phones. In general, visitors can comfortably assume that most devices are capable of 5 meters of hoizontal accuracy. The USDA Forest Service maintains a summary of tested horizontal accuracies for different receiver models. It is very important to know that while the GPS signal your device is receiving may be within 5 meters, the base map on your device is probably not. The park has direct and negative experience with most commercial base maps which generally depict incorrect road names, roads that don't exist, trails that go in the wrong direction, etc.
Vehicle Navigation Systems and GPS units may provide inaccurate information in the mountains—sending drivers the wrong way on one-way roads or leading them to dead ends in remote areas. Free park road maps are available in park visitor centers. Mobile device users can download a free application and detailed 2017 topographic maps for accurate navigation in areas without cellular service.
Visitors can check the accuracy of their device or smart phone by recovering a National Geodetic Survey Benchmark, with the Newfound Gap Parking Lot benchmark FB4079 being very easy to find, accessible, and a very unrestricted view of the sattelite constellation.
Park research partners collecting permitted data are encouraged to contact park staff to coordinate the park standard GPS data collection format. This allows the park to easily ingest your data, as well as make your research more easily reproduced. The most common scenario is needing to revisit established plot locations in order to measure the amount of population change in a particular species.
Many differential correction services provide coverage within the park boundary. For those front country areas with cellular reception, the states of North Carolina and Tennessee provide a real time correction service for a fee. The park is unable to provide access to park-owned correction accounts, researchers must provide their own equipment and subscription.
Satellite-based correction services generally work in most areas of the park, however dense canopy and deep valleys have been found to greate reduce the quality of the service, and in most areas of the park, convergence time is in excess of 30 minutes.
Contractors working for the park are encouraged to use Real-time kinematic (RTK) GPS when projects require surveying. In general, most previously established benchmarks are no longer recoverable and a local control point will need to be established. Installation of a control point other than a nail (rebar, concrete) will require concurrence from the parks NEPA specialist.
Depending on the scope and size of the project, the park may be able to establish an OPUS control point and optionally a shared solution.
Many differential correction services provide coverage within the park boundary. For those front country areas with cellular reception, the states of North Carolina and Tennessee provide a real time correction service for a fee. The park is unable to provide access to park-owned correction accounts, contractors must provide their own equipment and subscription.
Last updated: July 8, 2021