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Choke Ring GNSS

Overview
  • · Applies multi-feed technology to enhance phase accuracy and minimise the impact of antenna-related surveying errors
  • · Employs a specialised structural design to deliver excellent multipath suppression, high phase centre stability, and outstanding repeatability
  • · Incorporates a low-noise amplifier (LNA) with an integrated pre-filtering architecture
  • · Pre-filtering structure to suppress out-of-band interference before signal amplification
  • · Provides a high cross-polarisation ratio for improved resistance to multipath effects
  • · Features an integrated lightning protection circuit
  • · Includes an integrated voltage stabilisation circuit
Description

Choke ring antennas are high-performance antennas used in high-precision GNSS surveying and base station environments, specifically designed to effectively suppress multipath interference. By incorporating multiple concentric ring grooves (choke ring structures) around the antenna, reflected signals from the ground and surrounding structures are significantly reduced, thereby enhancing the quality of signals received directly from satellites.

The ring structure surrounding the antenna absorbs or attenuates low-elevation reflected signals, which substantially improves phase centre stability. Owing to these structural characteristics, choke ring antennas are able to maintain stable centimetre-level or sub-centimetre positioning accuracy when used with high-precision positioning techniques such as RTK and PPP.

In addition, choke ring antennas support multi-band and multi-GNSS operation, including GPS, GLONASS, Galileo, and BeiDou, ensuring high positioning reliability across a wide range of satellite signal environments.

FDA6002 FDA6009 FDA6007
Receiving frequency [MHz] 1164~1278MHz, 1559~1612MHz 1164~1278MHz, 1559~1616MHz 1197~1278MHz, 1557~1612MHz
Gain [dB] ≥ 6 dBi (Elevation angle 90°) ≥ 7 dBi (Elevation angle 90°) ≥ 7 dBi (Elevation angle 90°)
Polarisation RHCP RHCP RHCP
Axial ratio [dB] ≤ 3.0 dB (Elevation angle 90°) ≤ 3.0 dB (Elevation angle 90°) ≤ 3.0 dB (Elevation angle 90°)
VSWR ≤ 2.0 ≤ 2.0 ≤ 2.0
Impedance [Ω] 50 Ω 50 Ω 50 Ω
Cross polarisation ratio [dB] ≥ 25 dB (±60°) ≥ 25 dB (±60°) ≥ 25 dB (±60°)
Phase centre error [mm] < ±2 mm < ±1 mm < ±1 mm
LNA specifications
Frequency range [MHz] 1164~1278MHz,
1559~1612MHz		 1164~1278MHz,
1559~1616MHz 		1197~1278MHz,
1557~1612MHz
Gain [dB] 40±2 dB 50±2 dB 65±2 dB
VSWR < 2.0 < 2.0 < 2.0
Noise figure [dB] < 2.0 dB < 2.0 dB < 2.0 dB
Gain flatness [dB] ±2.0 dB ±2.0 dB ±2.0 dB
Input voltage [VDC] 3.3 ~ 12 VDC 3.3 ~ 18 VDC 3.3 ~ 18 VDC
Consumption current [mA] < 65 mA < 65 mA < 65 mA
Size [mm] ɸ180 x 180mm ɸ380 x 310mm ɸ322 x 265mm