Presentation on theme: "Pirazzi Gabriele Intecs S.p.A Bruxelles, 10/04/2008 “Study of an SDR GNSS receiver” Chapter of Rome M.Sc. In Advanced Communication and Navigation Satellite."— Presentation transcript:
Pirazzi Gabriele Intecs S.p.A Bruxelles, 10/04/2008 “Study of an SDR GNSS receiver” Chapter of Rome M.Sc. In Advanced Communication and Navigation Satellite Systems AFCEA’s Student Conference 2008
Slide 3 of 20 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.
Slide 4 of 20 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
Slide 5 of 20 Applications (1) Telecommunication RadarNavigation SDR One Terminal, multiple Applications.
Slide 6 of 20 Applications (2) User Terminal Hardware Layer Software Layer (management, control and configuration) Application Layer Installing, upgrading software module GPS Galileo UAV Radar SatCom Control Center
Slide 7 of 20 GNSS Receiver Structure Channel n Software Correlator Canale 2 Software Correlator Down conversion Frequency synthesizer Reference oscillator LNA A/D converter AGC Channel 1 Software Correlator IF Analogue RF Acquisition Tracking IF Digital Navigation processing HardwareSoftware
Slide 8 of 20 RF Carrier: Single IF conversion: Bandwidth (-3dB): 2 bit ADC (sign and mag) Sampling frequency: AGC TCXO Front-end
Slide 9 of 20 Acquisition phase Acquisition scope: Determinate the number of visible satellites. Coarse estimate of the beginning C/A code. Coarse estimate of the carrier included Doppler.
Slide 10 of 20 GPS, Giove-A real data acquisition