The Galileo and BeiDou signal plans have been devised to provide enhanced code-range noise and positioning accuracy in a wide range of challenging user scenarios, including the presence of multi-path, by means of MBOC (Multiplexed Binary Offset Carrier) coding schemes.
For the most accurate services (Galileo E1 PRS, E6 PRS and E5a+E5b and corresponding BeiDou services) this results in signal spectra which have two main lobes spaced apart from a suppressed carrier centre-frequency – in order to fully exploit this capability an antenna must maintain a constant group-delay over a relatively wide fractional bandwidth.
However, it is technically difficult to configure a self-resonant circularly polarised antenna with such a wide fractional bandwidth. Current antenna solutions attempt to achieve this by employing a simple single-pole frequency-response in which the Galileo signal lobes are located at the extreme band edges – a less than satisfactory approach that invariably fails to fully exploit and benefit from the MBOC coding scheme.
Helix Technologies is developing a lightweight, compact, high-performance E5/B5 antenna with a two-pole circular-polarised frequency response that is optimised to match the Galileo and BeiDou signal spectra whilst maintaining excellent circular polarisation properties.
Features of the antenna include:
- Matched frequency responses to the multi-lobed Galileo spectra shapes – which are composed of a combination of wide-band and narrow-band signal services.
- Equal group delay across modes to achieve consistent data clock-phase across the cluster of 3 modes forming the matched filter frequency response.
In addition our dielectrically loaded antennas provide other inherent compelling technical advantages that include:
- Unsurpassed gain/efficiency per unit of radiating volume.
- Improved accuracy and reliability of GNSS systems in urban environments with significant multi-path.
- Un-rivalled beam-width (omni-directionality).
- Robust operation when orientated in non-optimal direction (not perfectly upright).
- Operates when tightly embedded within integrated devices.
- Operation in slim-line packages where there is no room for a ground-plane.
- Preserves radiation efficiency near absorbing objects (for example the human body).
- Easily packaged into extremely robust packaging for durability and reliability.
For more information on our Galileo and BeiDou Wideband Antennas please get in Contact with us.