High-precision GNSS projects—such as geodetic surveying, CORS reference stations, deformation monitoring, precision agriculture, and scientific research—place extremely demanding requirements on antenna performance. Among all GNSS antenna types, choke ring antennas remain the gold standard for minimizing multipath, stabilizing the phase center, and delivering millimeter-level accuracy over long-term operation.
However, not all choke ring antennas are created equal. Choosing the right model requires a deep understanding of GNSS signals, installation environments, system compatibility, and long-term reliability. In this guide, we walk through how to choose the right choke ring antenna for high-precision GNSS projects, covering technical specifications, application-driven selection criteria, and common mistakes to avoid—while also sharing our practical experience from working closely with global GNSS users.
A choke ring antenna is a specialized GNSS antenna design that uses concentric metal rings (chokes) around the radiating element. These rings suppress surface currents and block low-elevation reflected signals, which are the main source of multipath interference.
In high-precision GNSS positioning—whether using RTK, network RTK, or PPP—multipath errors directly translate into coordinate instability and degraded convergence performance. This is why choke ring antennas are widely used in:
CORS and permanent reference stations
Geodetic and cadastral surveying
Crustal deformation and seismic monitoring
GNSS timing and synchronization
Scientific and academic research projects
Selecting the right choke ring antenna is therefore a strategic decision, not just a hardware purchase.
Before comparing specific antenna models, it's essential to define the performance requirements of your GNSS project.
For high-precision applications, the antenna must offer:
Excellent multipath rejection, especially at low elevation angles
High phase center stability across all frequencies
Minimal phase center variation (PCV) over azimuth and elevation
If your project involves long-term monitoring, even small phase center inconsistencies can accumulate into significant errors over time.
Modern GNSS systems are no longer limited to GPS alone. A high-quality choke ring antenna should support:
GPS (L1, L2, L5)
GLONASS (G1, G2, G3)
Galileo (E1, E5a, E5b, E6)
BeiDou (B1, B2, B3)
QZSS and SBAS (where applicable)
Multi-constellation, multi-frequency GNSS antennas improve satellite availability, shorten convergence time, and enhance positioning robustness in challenging environments.
One of the most important technical factors when choosing a choke ring antenna is frequency coverage.
Single-frequency choke ring antennas are suitable for basic reference applications but are increasingly outdated.
Multi-frequency choke ring antennas support advanced GNSS techniques such as PPP and multi-constellation RTK, making them the preferred choice for modern high-precision projects.
When evaluating frequency bandwidth, ensure the antenna fully covers all intended GNSS bands without performance degradation at band edges.
The antenna phase center is the effective electrical point where GNSS signals are received. For high-precision GNSS work, phase center behavior matters more than raw gain.
Low phase center offset (PCO)
Stable phase center variation (PCV) across frequencies
Availability of absolute calibration data
For CORS stations and scientific projects, antennas with published calibration files are strongly preferred, as they support consistent data processing and international data sharing.
Multipath remains one of the most stubborn error sources in GNSS positioning. Choke ring antennas are specifically designed to combat this problem, but performance varies by design.
Number and depth of choke rings
Symmetry of the antenna structure
Ground plane size and material
In urban environments, near reflective surfaces, or on building rooftops, superior multipath suppression can make the difference between reliable centimeter-level accuracy and unstable results.
High-precision GNSS projects often require 24/7 continuous operation in harsh outdoor environments. Antenna durability is therefore just as important as RF performance.
Operating temperature range
Waterproofing and IP rating
UV resistance and corrosion protection
Mechanical stability under wind, snow, and vibration
For permanent installations, choosing a robust choke ring antenna reduces maintenance costs and minimizes downtime over the system's lifecycle.
Even the best GNSS antenna can underperform if it is poorly installed.
When selecting a choke ring antenna, consider:
Standard mounting threads (e.g., 5/8″-11)
Compatibility with antenna masts and monuments
Cable routing and connector type (TNC, N-type, etc.)
Additionally, antenna size and weight matter for certain installations, such as rooftop deployments or lightweight monuments.
A high-quality choke ring antenna should feature:
Low noise amplifier (LNA) with a low noise figure
Stable gain across all GNSS bands
Good out-of-band signal rejection
This ensures clean signal reception even in RF-challenged environments and supports long cable runs without signal degradation.
Different high-precision GNSS projects prioritize different performance aspects.
Maximum multipath suppression
Absolute calibration availability
Long-term phase stability
Multi-frequency, multi-constellation support
High phase center repeatability
Lightweight but robust design
Extreme stability over time
Environmental durability
Compatibility with scientific GNSS receivers
Defining your application scenario upfront helps narrow down the most suitable choke ring antenna models.
Beyond specifications, the expertise of the antenna manufacturer plays a crucial role. Design philosophy, testing methodology, and application experience all influence real-world performance.
At Harxon, we design choke ring antennas specifically for high-precision GNSS applications. From the beginning, our focus has been on solving real-world positioning challenges rather than simply meeting theoretical specifications.
In our own product development, we emphasize:
Optimized choke ring geometry for low-elevation multipath suppression
Broad multi-frequency GNSS coverage aligned with modern receivers
Stable phase center performance validated through extensive testing
Robust mechanical design suitable for long-term outdoor deployment
By working closely with surveying professionals, CORS operators, and system integrators worldwide, we continuously refine our antenna designs to match evolving GNSS requirements. When we recommend a choke ring antenna, we do so based on application fit, not just datasheet numbers.
Even experienced GNSS users can make selection errors. Common pitfalls include:
Choosing based on gain alone instead of phase center performance
Ignoring future GNSS frequency requirements
Overlooking environmental durability for permanent installations
Failing to verify calibration data availability
Mismatching antenna and receiver capabilities
Avoiding these mistakes helps ensure your GNSS project delivers consistent, high-precision results over its entire lifecycle.
Choosing the right choke ring antenna for high-precision GNSS projects is a multidimensional decision involving RF performance, mechanical design, environmental reliability, and application-specific needs. By carefully evaluating frequency coverage, phase center stability, multipath suppression, and long-term durability, you can significantly improve positioning accuracy and system reliability.
Whether you are building a new CORS station, upgrading a geodetic network, or deploying a scientific GNSS monitoring system, investing in a well-designed choke ring antenna is essential. With the right selection—and support from experienced GNSS antenna specialists—you can ensure your high-precision GNSS project performs accurately, consistently, and reliably for years to come.
