In an increasingly interconnected world, GPS and other global navigation satellite systems (GNSS) are fundamental not only to navigation, but to many other applications: improving efficiency in agriculture, providing accurate timing for use in telecoms and financial systems, and much more.
GNSS/GPS is increasingly under threat, be that from unintentional RF interference or deliberate jamming by attackers seeking to disrupt, deny or spoof GNSS/GPS services.
Building resilience into your system is no longer optional but has become a necessity, and has been flagged as such by the European Space Agency and the Royal Institute of Navigation as well as by the civil aviation and maritime industries.
Whilst mitigation in the GNSS/GPS receiver often gets much of the attention, the first line of defence is often overlooked: the GNSS antenna.
High-performant designs such as Helix Geospace's helical GNSS antennas are tightly-tuned to the GNSS/GPS bands thereby removing out-of-band interference - from 4G mobile, radar and maritime uplinks amongst others - as well as multipath interference caused by reflections.
Interference in-band, whether it be accidental or intentional jamming, often originates from ground-level sources. By modifying the antenna design, a deep "null" (blind spot) can be created in the antenna's reception pattern at low elevations to block this ground-based interference whilst optimising clear reception of GNSS/GPS satellite signals. Helix Geospace's Horizon Nulling Antenna does just that, reducing any such interference or jamming by 30x, thereby enabling GNSS/GPS to function reliably.
Helix Geospace Horizon Nulling Antenna
For more sophisticated attacks involving multiple and dynamic jammers coming from different directions and elevations, a resilient GNSS system needs a more advanced approach. Whereas the horizon-nulling design delivers a static null, Controlled Reception Pattern Antennas (CRPA) modify their patterns in realtime to tackle the jammers.
This technology, once reserved for military applications, is now available for commercial use - Helix Geospace's CRPx is a good example, delivering military-grade resiliency in a compact, lightweight and ultra-low power integrated unit.
Many CRPA designs lean heavily on digital filtering to combat the jammers, but such an approach can result in the CRPA exhausting its resources - in short, the jammers win.
Helix's CRPx takes a radically different approach, continuously morphing its pattern to maximise GNSS/GPS signal reception whilst reducing the power level of interference; crucially, it's non-blocking and can handle any number of jammers.
Helix Geospace CRPx reception morphs realtime to combat jamming
By focusing on jamming suppression, many CRPAs inadvertently distort the GNSS/GPS signal, making it harder for the receiver to determine position. It can also trigger erroneous anti-spoofing alerts within the receiver, thereby requiring such functionality to be turned off - the CRPA may have succeeded in suppressing jamming, but in doing has made the GNSS/GPS system vulnerable to spoofing attacks and less able to provide an accurate position.
Transparent by design
Suppressing jamming without breaking the signal
In contrast, Helix's CRPx is transparent by design, removing any interference whilst delivering a strong and coherent signal to the GNSS/GPS receiver to support accurate positioning and anti-spoof analytics. By maintaining good phase stability, CRPx also supports high-accuracy GNSS/GPS services, something that many other CRPAs are unable to do.
The resilience checklist
- Start at the antenna — reject out-of-band and multipath interference before the receiver.
- Null the horizon to defeat static, ground-based jammers by up to 30×.
- Add CRPx for dynamic, multi-jammer environments — non-blocking by design.
- Keep the signal transparent so anti-spoofing and high-accuracy services keep working.
Improve your GNSS/GPS resiliency and enjoy better positional accuracy - upgrade to a Helix antenna today.
