No GNSS? Use Digital Magnetic Compass (DMC) as reliable back-up.

When GNSS signals are unavailable or jammed, alternative solutions for north finding are essential. The Digital Magnetic Compass DMC-pico offers enhanced targeting accuracy in environments where GNSS cannot be trusted. This article highlights the benefits of the Digital Magnetic Compass DMC-pico for military north finding.

DMC-pico: How does Magnetic North finding work?

Magnetic north finding is the oldest method for determining direction and remains a proven, trusted solution even today. Building on this time-tested approach, the DMC-pico’s advanced magnetic sensors measure the Earth’s magnetic field and correlate it with internal magnetic field maps. These measurements are then fused with the module’s inclination data to ensure reliable and precise directional information without the need for external satellite signals.

Comparing GNSS and DMC for North finding

Both GNSS and DMC based north finding come with distinct strengths and limitations. The most robust navigation solutions often combine both methods to maximize resilience.

GNSS

GNSS Benefits:

• Highly accurate position data
• No compensation required for magnetic disturbances
• Independent of magnetic disturbances

GNSS Limitations:

• Relies on weak and vulnerable satellite signals
• Can be easily jammed or spoofed
• Either consumes power when kept on continuously or requires startup time when turned off
• Provides only positional information; to determine north direction, GNSS must be in motion or use two antennas. For static applications, a gyro is needed, which is subject to drift over time.

DMC

DMC Benefits:

• Operates using the Earth’s magnetic field, which cannot be jammed or spoofed
• Supports continued operation when satellite navigation is compromised
• Works in GNSS-denied environments (indoors, underground, underwater)
• Functions in static applications without drifts
• Low power consumption and a short start-up time of only 50 ms make it ideal for power-sensitive applications.

DMC Limitations:

• Requires compensation for magnetic disturbances (such as metallic objects, currents, etc.)
• Accuracy depends on careful compensation prior to use
• Accuracy is affected by heavy accelerations

Maximized Reliability with GNSS & DMC

Consider using a DMC as a backup to GNSS based north finding to ensure reliable orientation, if GNSS signals are lost. When properly compensated, the DMC serves as a proven and robust alternative, providing reliable azimuth directions for mission-critical operations.