Antennas for Global Navigation Satellite System (GNSS) Signal Monitoring

ABSTRACT: The importance of precise satellite navigation is being realized throughout the world. In fact several systems are being deployed. Collectively these systems form the GNSS which offers improved accuracy and satellite availability. However due to differing requirements, new GNSS receivers are being developed. As a result, a GNSS antenna must be developed as well. The design of a GNSS antenna however is not a simple modification to existing GPS antenna technologies. Wider bandwidth and multipath signal suppression requirements increase the complexity of the design. As such, a unique combination of circularly polarized spiral antenna and ground plane with diffraction suppression technologies is being developed to accomplish this goal. During this program a GNSS antenna prototype shall be designed, fabricated and tested to demonstrate feasibility and functionality. A comprehensive set of RF tests including gain pattern and S-parameter measurements shall be performed and reported. This approach is expected to provide uniform maximum RCHP gain above horizon, low LHCP cross polarization in all directions, and minimum backlobe gain below horizon. A steep roll off in gain is also anticipated near horizon. Physically the antenna can be realized in a compact durable package. Furthermore, cost effective materials and processes are employed wherever possible. BENEFIT: Worldwide use of the GNSS is expected to be prolific. Just as the current GPS has grown in popularity throughout the commercial sector so too shall the GNSS. The two big advantages of the GNSS are improved accuracy and superior satellite availability. With an increasing global economy the world is becoming a smaller place whereby business and travel abroad are more commonplace than ever. As such, this new capability is even more desirable. As the need for GNSS grows, so does the need for GNSS receiver antennas. In fact, GNSS can be expected to be utilized in a variety of environments including land, sea and air. Because antennas must be strategically located without obstruction, often they must be amenable to unusual environmental conditions and volumetric envelope constraints. The push for a compact GNSS antenna package feeds right into such demands. And because there are many possible vehicles, structures, or even personnel whereby these receivers may end up, the variations in GNSS antenna configurations can be quite significant. Since commercialization is a very real opportunity, it is imperative to focus on the objectives described above. In a nutshell, the antenna must be designed to be functional, compact, and lightweight, as well as inexpensive in terms of materials and manufacturing. If these criteria can be met, then the potential for this technology is substantial for years to come.