AGGA-3: A Next Generation GNSS Baseband ASIC

Stefan Berberich, Stephan Fischer, F. Griesauer, P. Silvestrin and R. Weigand

Abstract:	The AGGA-3 (Advanced GPS/GALILEO ASIC) is a radiation-tolerant, low power consumption new generation GNSS baseband ASIC. The AGGA-3 includes a GNSS baseband processor, the LEON-FT fault-tolerant microprocessor with its powerful IEEE-754 compliant FPU (GRFPU), an FFT module, UART’s and 4 SpaceWire interfaces. The digital hardware and its interfaces are highly flexible, which makes this component useful for a wide range of applications ranging from platform positioning to Earth observation such as radio occultation, scatterometry, precise orbit determination in support of radar interferometry, etc. The GNSS baseband processor is capable of processing the current and future GPS signals L1 C/A, L2C, L5, P(Y) and the open access Galileo signals L1-B, L1-C, E5a, E5b. It includes digital down-conversion, beam-forming, enhanced power level detection, code and carrier loop aiding support, and optimised raw sampling for open-loop signal tracking. Codeless tracking of GPS L2 P(Y) signals is supported. Implementation losses are reduced thanks to 3-bit pre-correlation processing. Functional blocks usually located in software have been included in hardware with a high flexibility to accelerate the signal processing of the new GPS and Galileo wideband signals and to increase the number of processed signals. 36 highly configurable single-frequency GNSS channels are available. Each channel includes 5 complex code correlators for narrow spacing correlation, a dual integration stage for data, decryption or secondary code stripping, a secondary code sequencer, and a carrier and code aiding unit. The data from the GNSS baseband processor are transferred to memory by direct memory access (DMA). 2 interrupt controllers assure the appropriate priority for data processing by the LEON RISC processor. The timebase generates the required clocks and assures the correct timing. The AGGA-3 includes a 128 point integer FFT module for e.g. fast signal acquisition support.
Published in:	Proceedings of the 17th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2004) September 21 - 24, 2004 Long Beach Convention Center Long Beach, CA
Pages:	1480 - 1487
Cite this article:	Berberich, Stefan, Fischer, Stephan, Griesauer, F., Silvestrin, P., Weigand, R., "AGGA-3: A Next Generation GNSS Baseband ASIC," Proceedings of the 17th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2004), Long Beach, CA, September 2004, pp. 1480-1487.
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