Key Takeaways
- GNSS signals are extremely weak and therefore highly susceptible to jamming and spoofing, threatening the reliability of positioning, navigation, and timing (PNT) for defence platforms.
- Calian’s resilient antenna portfolio starts with XF+ extended filtering, which provides deep out‑of‑band rejection (≈80 dB) and cross‑band isolation to keep lower GNSS bands usable when the upper band is attacked.
- Controlled Reception Pattern Antenna (CRPA) technology actively steers nulls toward jamming sources, suppressing interference by 20–40 dB in real time while preserving legitimate signals from other directions.
- The CR7712EXF offers low‑SWaP, two‑element, single‑null anti‑jam capability for UAVs and lightweight systems, drawing only 60 mA at 5 V and providing basic jamming state reporting.
- The CR8894SXF+ steps up to a four‑element, dual‑band CRPA supporting multiple constellations (GPS L1/L2, Galileo E1/E5b, GLONASS G2/G3, BeiDou B1/B2b, plus M‑Code) and can null‑steer against up to six simultaneous jammers, with enriched NMEA SITREP situational‑awareness output.
- Complementary Fixed Reception Pattern Antennas (FRPAs) such as the AJ977XF+ MAR and TW3742AJ add passive, low‑cost layers that address low‑angle interference or provide cost‑effective anti‑jamming without active electronics.
- All antennas are designed, tested, and manufactured in Calian’s Ottawa facility, leveraging Tallysman’s heritage in high‑precision GNSS, and are qualified for harsh airborne, maritime, and ground‑vehicle environments.
- A modular, layered approach lets platform integrators match the right mix of active CRPAs and passive FRPAs to specific SWaP, power, and threat‑level requirements, avoiding a one‑size‑fits‑all solution.
Threat Landscape Drives Need for Resilient PNT
Across modern contested theaters, inexpensive, commercially available jammers can blanket wide areas with disruptive RF energy, while advanced spoofing techniques inject false location data into GNSS receivers without triggering obvious alarms. For UAVs, autonomous ground vehicles, maritime craft, and other mission‑critical systems, compromised PNT directly erodes navigation accuracy, targeting precision, and overall operational effectiveness. Consequently, maintaining reliable Positioning, Navigation, and Timing (PNT) has shifted from a desirable feature to a core design requirement for any defence platform expected to operate where GPS availability cannot be assured.
Inherent Vulnerability of GNSS Signals
GNSS transmissions arrive at Earth’s surface at extraordinarily low power levels—on the order of −130 dBm—making them intrinsically vulnerable to both intentional interference and unintentional RF sources. As jamming and spoofing tools become more accessible and sophisticated, the signal‑to‑noise ratio at the receiver can collapse rapidly, rendering standard GNSS front‑ends ineffective. Recognizing this, system architects have moved toward layered protection strategies that begin at the very first point of signal entry: the antenna.
XF+ Extended Filtering as the First Line of Defense
Before any digital null‑steering or signal authentication can occur, the antenna must deliver the cleanest possible RF spectrum to the receiver. Calian’s XF+ extended filtering technology achieves this by applying deep out‑of‑band rejection across the 400 MHz‑to‑3 GHz band, providing roughly 80 dB of attenuation against LTE, cellular, and other external RF interferers. The “+” denotes a cross‑band isolation feature built into the low‑noise amplifier (LNA) chain: if an adversary jams the upper GNSS band, the lower bands remain usable because energy from the jammed band does not leak into them. This front‑end cleaning dramatically lowers the noise floor and establishes a robust foundation for downstream active interference mitigation.
How CRPA Technology Actively Shapes Reception
Controlled Reception Pattern Antennas (CRPAs) extend protection beyond static filtering by dynamically shaping the antenna’s reception pattern. Unlike an omnidirectional antenna that receives equally from all directions, a CRPA combines multiple antenna elements and continuously computes steering vectors to place deep nulls—typically 20‑40 dB of attenuation—in the directions of detected jammers. As the jammer moves or the host platform maneuvers, the null‑steering algorithm updates in real time without operator intervention, preserving reception of legitimate GNSS signals from other angles. Calian’s CRPAs also output proprietary NMEA SITREP messages over RS‑232/RS‑422, reporting jamming state, estimated jammer direction, and power level, thereby turning the antenna into a source of electronic‑battlefield situational awareness.
CR7712EXF: Low‑SWaP Anti‑Jam for Compact Platforms
The CR7712EXF is a two‑element, single‑null adaptive beamforming antenna tuned to the L1/E1/B1 band. Optimized for low Size, Weight, and Power (SWaP) applications, it draws only 60 mA at 5 V—critical for UAVs, lightweight autonomous ground vehicles, and other platforms where every gram and milliwatt matters. The antenna forms a planar null to suppress interference in the upper GNSS band and provides a simple serial interface that signals whether jamming has been detected. Because it works with standard commercial‑off‑the‑shelf (COTS) GNSS receivers, integration into existing architectures does not require specialized receiver hardware, delivering meaningful anti‑jam capability without imposing prohibitive SWaP penalties.
CR8894SXF+: Multi‑Band, High‑Capacity Anti‑Jam with Situational Awareness
For platforms needing broader protection across multiple constellations, the CR8894SXF+ offers a four‑element dual‑band CRPA. It supports GPS L1/L2, Galileo E1/E5b, GLONASS G2/G3, BeiDou B1/B2b, and the military M‑Code on both L1 and L2. The four‑element array enables the mitigation of up to three jammers per band—six in total—with null depths ranging from 20‑40 dB depending on conditions, a capability essential in dense electronic‑warfare environments where several interferers may operate simultaneously. Like its smaller sibling, it reports jamming state, estimated jammer direction, and signal status via NMEA SITREP over RS‑232/RS‑422, but with richer detail. Rated IP67 and drawing 150 mA at 5 V, the CR8894SXF+ employs surface‑mount packaging for flexible integration across a wide variety of platform types.
Layered Resilience: Combining CRPAs with Fixed Reception Pattern Antennas
While CRPA technology addresses interference at the antenna level through active null‑steering, complete GNSS resilience for mission‑critical systems often requires a layered approach. Calian complements its CRPA line with Fixed Reception Pattern Antennas (FRPAs) that provide passive, cost‑effective protection tailored to different threat profiles. The AJ977XF+ MAR triple‑band antenna is optimized to mitigate low‑angle interference and is ideal for timing‑critical applications. The TW3742AJ single‑band FRPA offers a straightforward anti‑jamming layer that reduces jammer impact without active electronics. By combining an active CRPA (for real‑time, adaptive null steering) with one or more FRPAs (to handle low‑elevation or broadband interference), designers can create a modular, scalable resilience stack that matches the specific SWaP, power, and threat‑level demands of airborne, maritime, or ground‑vehicle platforms.
Built for the Mission Environment: Canadian Engineering and Rugged Qualification
Every antenna in Calian’s resilient GNSS portfolio is designed, tested, and manufactured at the company’s Ottawa facility, drawing on decades of expertise from the Tallysman legacy in high‑precision GNSS and RF design. This centralized approach ensures stringent quality control, traceable supply chains, and compliance with defence‑procurement standards. All units undergo rigorous environmental, mechanical, and electromagnetic testing—including temperature extremes, vibration, shock, and EMI/EMC—validating suitability for airborne, maritime, and ground‑vehicle operations. The result is a family of antennas that not only delivers cutting‑edge anti‑jam and spoof‑resistance performance but also meets the rugged reliability expectations of modern defence missions.