Android GNSS Measurements - Inside the BCM47755

Steven Shade and Premal H. Madhani

Abstract:	Android based smartphone platforms have made it possible for users to get access to various raw measurements from the embedded GNSS chip. This is a step in the right direction, not only for people in navigation community but also for anyone with a curious mind. The new generation consumer grade GNSS chips like the Broadcom BCM 47755 are supporting multiple GNSS bands in addition to multiple GNSS constellations, and have the capability to provide measurements that can help achieve accuracies close to the ones obtained by high cost, high precision receivers, and at fraction of power consumption compared to current single band chips. We think that the users will be able to write more effective algorithms and code to process these measurements, if they know the intricacies involved in generating these measurements and what information they contain. We will discuss in this paper what subset of measurements and what characteristics of those measurements will be needed for certain end user applications. We will provide some insights about how the measurements from the BCM 47755 are formed and what corrections have been applied to the measurements before they are made available to the Android interface. We will also discuss how the measurements change under differing conditions like low signal conditions and during duty cycling.
Published in:	Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018) September 24 - 28, 2018 Hyatt Regency Miami Miami, Florida
Pages:	554 - 579
Cite this article:	Shade, Steven, Madhani, Premal H., "Android GNSS Measurements - Inside the BCM47755," Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018), Miami, Florida, September 2018, pp. 554-579. https://doi.org/10.33012/2018.16001
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