GNSS Antenna
The receiving element in GNSS-enabled devices that captures satellite signals for positioning. Requires unobstructed sky view, limiting GNSS to outdoor and open-air applications. Antenna design significantly impacts signal reception quality, multipath rejection, and positioning accuracy. Industrial GNSS tags integrate compact patch antennas, while high-precision applications use larger ground-plane antennas to minimize multipath errors.
GNSS antennas operate at satellite signal frequencies: GPS L1 (1575.42 MHz), GPS L2 (1227.60 MHz), GLONASS L1/L2, Galileo E1/E5, BeiDou B1/B2. Multi-constellation, multi-frequency antennas receive signals from all systems simultaneously, improving satellite availability and accuracy. Antenna types in industrial RTLS: patch antennas (compact, low-profile, integrated into tags - most common for industrial wearables and asset tags, 25-50 mm diameter), helical antennas (omnidirectional, better at low elevation angles, vehicle-mounted applications), and choke ring antennas (high-performance with excellent multipath rejection, used in reference stations and precision applications). Key performance parameters: gain (dBi, higher improves weak signal reception), axial ratio (circular polarization quality, target below 3 dB), phase center stability (critical for RTK precision). Antenna placement: roof mounting preferred for maximum sky view; avoid proximity to metal surfaces creating reflections (minimum 10 cm clearance recommended).
Industrial RTLS antenna considerations: outdoor vehicle tracking (forklift, yard tractor, construction equipment) requiring reliable reception during movement and near buildings; hybrid indoor-outdoor systems where antenna must maintain signal near building entrances; high-precision RTK-guided outdoor AGVs requiring phase-center-stable antennas. Cable length affects signal quality: coaxial cable introduces 3-5 dB loss per 10 meters, requiring low-loss cable or antenna-mounted pre-amplifiers for long runs. Industrial GNSS antennas cost $15-200 depending on performance tier; high-grade survey antennas for RTK $300-2000. Integration into compact wearable badges remains challenging due to size constraints - vehicle-mounted units achieve significantly better GNSS performance than miniaturized personnel badges.