AJ977XF+

The AJ977XF+ is a high-performance anti-jam GNSS antenna designed for mission-critical positioning, navigation, and timing applications. Supporting all major global satellite constellations across triple frequency bands, it ensures reliable operation even in challenging RF environments.

Overview

The antenna supports GPS, QZSS, GLONASS, Galileo, BeiDou, and NavIC signals, along with regional Satellite-Based Augmentation Systems (SBAS) including WAAS, EGNOS, MSAS, and GAGAN. Its advanced design combines extended filtering and low-elevation signal suppression to maintain signal integrity in the presence of interference and jamming.

Key Features

The AJ977XF+ delivers excellent signal quality with a typical axial ratio of 1.0 dB and low noise performance at 2.5 dB. Its high-gain LNA (40 dB typical) ensures strong signal reception, while extended XF+ filtering provides superior rejection of unwanted signals.

The antenna operates across a wide input voltage range (2.5 to 16 VDC) and includes robust protection features such as 15 kV ESD immunity. Its IP67-rated enclosure ensures reliable performance in harsh environmental conditions, and it fully complies with RoHS and REACH standards.

A key advantage is its ability to attenuate signals by approximately 20 dB at low elevation angles (0° to 15°), significantly reducing the impact of ground-based interference sources.

Performance Advantages

Designed specifically to mitigate jamming, the AJ977XF+ uses a Low Elevation Angle Nulling Antenna (LEANA) radiation pattern to suppress interference originating near the horizon. This allows the antenna to operate effectively much closer to jamming sources compared to standard GNSS antennas.

The combination of LEANA technology and XF+ extended filtering provides strong protection against both in-band and out-of-band interference. The antenna maintains excellent gain and phase center stability at higher elevation angles, ensuring high-precision positioning.

Its circular polarization across the full bandwidth enhances signal reliability, while advanced multipath rejection improves accuracy in urban or reflective environments.

Advanced Filtering Technology

Calian’s XF+ filtering technology delivers more than 80 dB of out-of-band rejection across a wide frequency range (700 MHz to 2500 MHz). It separates upper and lower amplification channels, ensuring continued operation even if one channel is affected by interference.

This filtering is particularly effective against modern interference sources such as LTE signals, Ligado transmissions, and Inmarsat communications, all of which can degrade GNSS performance. By mitigating these signals, the AJ977XF+ ensures optimal receiver performance in congested RF environments.

Applications

The AJ977XF+ is ideally suited for mission-critical GNSS applications requiring high reliability and resilience to interference. Typical use cases include:

• Precision positioning and navigation
• Timing and synchronization systems
• Law enforcement and public safety operations

Conclusion

With its advanced anti-jamming capabilities, robust filtering technology, and multi-constellation support, the AJ977XF+ is a powerful solution for maintaining GNSS performance in challenging and interference-prone environments.