SOLUTIONS

GNSS compassing determines true heading by comparing carrier phase measurements between two GNSS antennas, with no dependence on the Earth's magnetic field. This eliminates the heading errors caused by magnetic distortions from steel structures, motors, power cables, and electromagnetic interference — distortions that are unavoidable on most operational platforms. GNSS compassing also requires no magnetic calibration to the host vehicle and provides consistent accuracy regardless of geographic location or magnetic environment.

Heading accuracy is a function of antenna baseline length. With VectorNav's dual-antenna products, typical performance is 0.30°–0.60° RMS at 0.5 m baseline, 0.15°–0.30° RMS at 1.0 m baseline, and 0.08°–0.15° RMS at 2.0 m baseline. Longer baselines deliver better accuracy, so antenna placement should maximize separation within the platform's physical constraints.

Yes. This is one of the primary advantages over single antenna GNSS/INS heading, which accumulates drift at rest. GNSS compassing provides reliable heading at zero speed, making it essential for applications like SATCOM on-the-move (which must acquire the satellite before moving), static survey, pre-mission alignment, and any platform that spends time stationary between operations.

When GNSS signals are temporarily lost, VectorNav's loosely coupled INS filter maintains heading continuity using inertial aiding. The system bridges short GNSS disruptions — from multipath, terrain masking, or brief interference — without losing heading reference. The duration and accuracy of this bridging depends on the IMU grade: Tactical sensors maintain heading through longer outages with less drift.

GNSS compassing is available on VectorNav's dual-antenna INS products: the VN-300 (Industrial) and VN-310 (Tactical). Both products integrate GNSS compassing with full inertial navigation, so position, velocity, and attitude are delivered as a unified, time-synchronized solution.

Mount the antennas with the longest practical separation and a clear view of the sky. It’s also important that both antennas “see” that same sky, so minimize any obstructions between the two antennas. The baseline between antennas should be measured and configured in the system. VectorNav's support engineering team provides antenna placement guidance for specific platforms, including recommendations for minimizing multipath and optimizing heading accuracy within the platform's physical constraints.