GNSS on the Go–Sensitivity and Performance in Receiver Design

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As GNSS positioning moves into ever more mobile and electromagnetically and operationally challenging environments, receiver designers must figure out how to make user equipment sensitive and robust enough to perform well while simultaneously minimizing cost and power requirements. This article covers such issues of receiver design as internal signal interference, integration with existing platofrm architecture, software-based designs, and common errors in design assumptions.

Malcolm Lomer, Stefan Fulga, and Peter Gammel
SiGe Semiconductor

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Position tracking is no longer limited to fixed automotive applications or expensive handheld tracking systems.

Consumer demand combined with recent innovations in GNSS technology is making position tracking a must-have feature in a wide range of cost-sensitive applications, including cellular handsets, personal navigation systems, and other consumer electronic devices.

Developing a GNSS position tracking subsystem for consumer electronic devices can appear to be a daunting challenge. Developers must not only keep down costs while maximizing performance and accuracy, they have to do so using RF technology with which they may have little experience.

Sensitivity is the key to accuracy of a GNSS receiver. The signals that a GNSS receiver tries to detect and process are buried in noise; therefore, the task of maintaining signal integrity is a key challenge for many developers.

This article describes how becoming familiar with a few key aspects of RF design can help developers avoid many of the seemingly arbitrary design decisions that can cause position tracking functionality to fail to achieve sufficient accuracy. It also highlights how developers can exploit software-based GNSS baseband architectures to reduce RF subsystem complexity while further increasing sensitivity and positioning accuracy. . .

Conclusion
. . . By understanding that RF sensitivity is the key to accuracy, developers can avoid common design pitfalls that delay time to market and increase system cost.

Additionally, by using the proper components and taking advantage of next-generation innovations such as software-based baseband processing, developers can achieve the best sensitivity and accuracy without having to become RF experts themselves.

(For the complete article, including figures, charts, and images, please download the PDF version at the link above.)

Author Profiles

Stefan Fulga, director of strategic marketing for SiGe Semiconductor’s strategic marketing activities in GNSS, WiFi and WiMAX segments, previously led the development of the company’s GNSS products as a director of engineering. He has been with SiGe Semiconductor for eight years, working on Bluetooth power amplifiers, cable telephony tuners, and GNSS products. Prior to that he worked at Nortel’s semiconductor group as a mixed signal IC design engineer. Fulga holds a bachelor of electrical engineering degree from Concordia University in Montreal, Canada, and a PLD degree from Harvard Business School.

Peter L. Gammel, SiGe Semiconductor’s chief technical officer and vice-president of Engineering, has worked with single-electron devices, superconducting devices, and MEMS and RF acoustic wave devices for more than 20 years. He is well acquainted with the processes of intellectual property investment and new product and funding development. Gammel previously served as VP engineering at a venture-backed startup, assembling and managing a 15-person team to develop RF acoustic wave products. He was CTO at both AdvanceNanotech, Inc. and Agere Systems (analog products business unit), and was a research director at Bell Laboratories. He has more than 200 referred technical publications and more than 25 patents issued and in process. He holds a Ph.D. in physics from Cornell University and bachelor of science degrees in physics and mathematics from Massachusetts Institute of Technology (MIT).

Malcolm Lomer is product marketing manager, GNSS Solutions, for SiGe Semiconductors, having marketed GNSS products for six years. He has more than 15 years technical, sales, and marketing experience in the GPS market. In his current position, he is responsible for SiGe Semiconductor’s GPS and GNSS RF front-end IC products. Prior to joining SiGe, Lomer worked at SiRF Technology as a field application engineer. Before that he held the position of market development manager for GPS at Zarlink Semiconductor. Lomer holds a bachelor of science degree in electronics from the University of Manchester’s Institute of Science and Technology in the United Kingdom