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Pirazzi Gabriele Intecs S.p.A

M.Sc. In Advanced Communication and Navigation Satellite Systems. Chapter of Rome. AFCEA’s Student Conference 2008. “Study of an SDR GNSS receiver”. Pirazzi Gabriele Intecs S.p.A. Bruxelles, 10/04/2008. Agenda. SDR Definitions SDR Applications GNSS receiver Acquisition Phase GPS

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Pirazzi Gabriele Intecs S.p.A

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  1. M.Sc. In Advanced Communication and Navigation Satellite Systems Chapter of Rome AFCEA’s Student Conference 2008 “Study of an SDR GNSS receiver” Pirazzi GabrieleIntecs S.p.A Bruxelles, 10/04/2008

  2. Agenda • SDR Definitions • SDR Applications • GNSS receiver • Acquisition Phase • GPS • Giove-A(Galileo) • SBAS • Tracking Phase • GPS • Giove-A(Galileo) • SBAS • Space Software Receiver

  3. Definitions • Software Radio:the digitization is at the antenna and all of the processing required is performed for the radio by software. • Software Defined Radio:the digitization is performed at some stage downstream from the antenna, typically after wideband filtering, low noise amplification, and down conversion to a lower frequency in subsequent stages.

  4. SDR purpose • The purpose of the Software Radio: • Move the ADC (analog-to-digital) as close as possible to the antenna. • Elaborate the samples obtained through a reprogrammable processor. • Advantages: • Removing analog components with non-linear characteristics, depending on the temperature and age. • Single antenna for multi-constellation, multiband and multi-modes systems . • High flexibility in the implementation of new algorithms: update software without replace hardware. • Reducing costs and maintaining

  5. Applications (1) SDR One Terminal, multiple Applications.

  6. Applications (2) Radar Galileo GPS UAV SatCom Installing, upgrading software module Application Layer Software Layer(management, control and configuration) Hardware Layer Control Center User Terminal

  7. GNSS Receiver Structure Hardware Software AGC Channel n Software Correlator Canale 2 Software Correlator Channel 1 Software Correlator LNA Downconversion A/Dconverter IF Digital RF IF Analogue Referenceoscillator Frequencysynthesizer Acquisition Tracking Navigation processing

  8. Front-end • RF Carrier: • Single IF conversion: • Bandwidth (-3dB): • 2 bit ADC (sign and mag) • Samplingfrequency: • AGC • TCXO

  9. Acquisition phase • Acquisition scope: • Determinate the numberofvisiblesatellites. • Coarse estimate of the beginning C/A code . • Coarse estimate of the carrierincluded Doppler.

  10. GPS, Giove-A real data acquisition

  11. Incoherent Integration SBAS

  12. Unexpected Signal: GAGAN! • Geostationary satellite acquired, tracked and decoded: • AOR-E • Artemis • IOR-W • Gagan GAGAN EGNOS • Analisis of Message 18 • (Ionosperic Grid Points • Mask, IGP) and Message 9 • (Geo Navigation Message) • confirm it’s Gagan! • First signal transmitted at the end of December 2007

  13. Tracking • Tracking scope: • Trackingovertime the carrier and the GPS code. • ImplementedTrackingclosedloop: • PLL (PhaseLockLoops) Costas 2° order. • DLL (DelayLockLoops) incoherent 2° order. • FLL (FrequencyLockLoops) del 1° order.

  14. Tracking Giove-A E1B

  15. Tracking GPS real data

  16. Giove-A Message Decoded (Viterbi) Packets 5-8 Packets 1-4 Carrier Status Nav. Data Health Packets 5-8 First Frame Packets 1-4

  17. MIOSat mission MIssioneOtticasu microSATellite

  18. SSR Requirements

  19. SSR Scheme • Satellite or System on Chip (SoC). • Less volume and mass. • Reduced power consumption. • Fewer interconnects, solder joints e bound wires. • Soft-core CPU: Leon3

  20. Q & A SESSION “Study of an SDR GNSS receiver” Thank you for your attention Pirazzi Gabriele Intecs S.p.A. Bruxelles, 10/04/08

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