Juniper Systems Logo

Optimize GNSS Receiver for Use Under Forest Canopy

Article #16995

Forest canopy can make it difficult for any GNSS (GPS) receiver to locate satellites and provide precise geospatial positioning. This was demonstrated for the original Geode (aka GNS1). The following suggestions may be helpful in such conditions.

  • Reduce the antenna mask angle (such as from the default 10° to 5° or 0°) to increase the number of satellites the Geode can see. The quality of signal from low-angle satellites may be worse than high-angle satellites; however, when high-angle satellite signal is blocked, lower quality signal can be better than nothing.

  • Make use of point averaging settings, if available in your app. Choosing to average a higher number of points and allowing a longer period of time between the points being averaged can provide better positioning of the final recorded point.

  • Post-processing GNSS (GPS) data to apply additional corrections later can potentially provide better accuracy, even if data was recorded in poor conditions (such as under tree canopy).

  • Enable multi-GNSS. Being able to receive GPS, GLONASS, and other GNSS signals allows for more available satellites to be in view, which gives a higher chance of getting better accuracy.

  • If you can receive a good signal reasonably nearby, you may be able to offset a recorded position. You could use a laser range finder to precisely find the distance of the offset.

  • An external antenna that could be raised higher into or above the canopy, such as mounted on a tall pole, could provide better signal.

  • SBAS (such as WAAS), ATLAS, and other satellite-based correction services would have the same signal limitations under tree canopy as general GNSS/GPS satellites. If you can arrange a clearer view to those geosynchronous satellites above the equator, they could help.

  • If available, enable multi-frequency for L1, L2, and L5 signals.

Note: Connecting to an RTK network using NTRIP may be difficult due to limited internet connectivity in locations obscured by tree canopy. Also, each mount point has a limit of compatible satellites. The compatible satellites will likely also be restricted by overhead obstructions.