What do a shipping container loaded with luxury SUVs, a bulldozer, a commercial generator, and a jobsite trailer full of tools have in common? They’re all examples of high-value assets whose precise, continually updated location is critical for protecting them against theft, misuse, underutilization, and more.
They’re also significantly different in terms of size, use case, and other aspects. Those differences are important considerations when choosing a GNSS antenna.
When to Use a Directional Antenna
Bulldozers and other heavy construction equipment frequently are equipped with GNSS systems for achieving precise grading and other work. These are separate from GNSS systems used for tracking applications such as anti-theft geofencing and asset management.
The tracking antenna should be installed in a location that provides an unobstructed view of the sky, free from obstructions that could block or reflect the satellite signals. Potential locations include the inside top of the windshield, the dashboard, and on the roof.
A directional GNSS antenna — such as a patch, quad helix, or cross dipole — is recommended because the installed orientation is well known or reasonably well known. If the antenna will be externally mounted, then the metallic cab roof will serve as the ground plane and thus help narrow down the choice of GNSS antenna to patches and crossed dipoles. If the location doesn’t provide a ground plane, then a quad helix antenna is the ideal choice. (For more information, see “GNSS Antennas: How to Choose Between Directional and Omnidirectional Designs.”)
When to Consider a Multi-Constellation GNSS Antenna
Shipping containers typically travel several thousands of miles, which can include areas that some GNSS constellations cover better than others. If the cargo requires continuous, high-accuracy tracking, one solution is a GNSS module and antenna that support multiple constellations, such as GPS, GLONASS, and BeiDou. (For more information, see “Navigating the L1, L2, and L5 Band Options for GNSS.”)
One example is the Taoglas SynergyX MA1557, which supports all GNSS frequencies, including GPS/QZSS L1/L2/L5/L6, GLONASS G1/G2/G3, Galileo E1/E5a/E5b/E6, BeiDou B1/B2a/B2b/B3, NAVIC L5, and SBAS (WAAS/EGNOS/GAGAN/SDCM/SNAS). The MA1557 also has a low-profile, permanent-mount enclosure that’s IP67 rated, a design that minimizes the chance of damage from water or from being scraped during intermodal loading and unloading.
Directionality
Some mobile assets travel to locations where the tracking device is likely to spend a significant amount of time in multipath environments. One example is a jobsite trailer in Manhattan, where GNSS signals will bounce off the tall buildings, leading to delays in their arrival at the antenna and thus creating errors in positioning calculations.
These problems can be mitigated by choosing a GNSS antenna that is designed to reject multipath signals using high directionality or other techniques. (For more information, see “Multipath Analysis Using Code-Minus-Carrier Technique in GNSS Antennas.”)
Staying Grounded
The ground plane is an important factor in terms of antenna performance and thus application performance. For example, the metal roof of a bulldozer or jobsite trailer acts as the ground plane and helps improve performance. But if the antenna is mounted inside at the top of the windshield, metallic window tinting could attenuate the GNSS signals.
The Taoglas MA114 antenna, which is designed to be mounted directly onto metal surfaces with no performance degradation. The MA114 also supports GPS, GLONASS, BeiDou, and Galileo. This combination is valuable if one of the business objectives is to have a single tracking platform for gensets that will be sold or leased in multiple countries or continents.
