Low-cost mitigation of ground-based GNSS interference & jamming

Written by David Pollington | Mar 27, 2026 12:00:00 PM

Jamming signals often originate at low elevations from ground-based transmitters. By carefully designing the radiation pattern of a GNSS antenna such that it is less sensitive to signals arriving between -10° to +15° from horizon provides an effective mechanism for suppressing this interference.

Helix Geospace have developed a high-performance GNSS/GPS antenna that does just that.  The Horizon Nulling Antenna (HNA) utilises a conical directivity pattern to minimise signals received at elevations below 15° (providing 15dB rejection) whilst supporting multiple constellations & bands for maximum satellite tracking (GPS L1/L5, Galileo E1/E5, and QZSS L1/L5).

 

Through utilising Helix's patented DielectriX technology, Helix's HNA is also very compact (ø75mm x 52mm) thereby providing the highest available signal-to-noise ratio in contested environments per unit of size/volume.

Helix's HNA is suitable for all GNSS applications including high-precision carrier-phase GNSS, and resilient PNT for telecoms networks and other critical national infrastructure (CNI).  

Find out more here.

Mitigates adjacent band interference

  • Patented DielectriXTM antenna technology provides sharp frequency selectivity that tightly tunes to the GNSS bands whilst blocking adjacent band interference

Reduces multipath interference

  • Excellent circular polarisation purity (low axial ratio) without the need for a ground-plane, reduces multipath interference significantly

Platform independent

  • Balanced and isolated from platform ground ensures high immunity to common-mode noise and very low proximity de-tuning caused by nearby objects

Suitable for high accuracy applications

  • Tight phase centre and consistent group delay over wide azimuth variations enables use with carrier-phase GNSS (e.g., RTK)