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AFCEA’s International Student Conference 2009 Brussels, October 28 2009 SDR GNSS Receiver Acquisition Module LabVIEW Implementation Lt. Pasquale Digregorio
AFCEA’s International Student Conference 2009
Brussels, October 28 2009
SDR GNSS ReceiverAcquisition Module
LabVIEW Implementation Lt. Pasquale Digregorio
Introduction : Workgroup
GNSS Ricever : Hw-based vs Sw-based
Acquisition Module : Hw e Sw approach
LabView : implementation
Results : real GPS signal acquisition
Conclusions
SUMMARY22
Cpt. Francesco Bartolozzi
Cpt. Alberto De Sanctis
Gabriele Mariani
Lt. Efer Miotti
3
RF to IF converter
Antenna GNSS
Acquisition Tracking Navigation
Code-phase Delta Doppler
ObservablesNavigation Data PVT
A/D converter
RF to IF converter
Antenna GNSS
Acquisition Tracking Navigation
Code-phase Delta Doppler
ObservablesNavigation Data PVT
SOFTWARSOFTWAREE
HARDWAREHARDWARE
SUMMARY44
A/D converter
Acquisition
SOFTWARESOFTWAREHARDWAREHARDWARE
GPS signalLocal Code
Satellite in view (PRN code)
Delta Doppler
Code-phaseCode-phase
Search in 3 dimention space:
0 100 200 300 400 500 600 700 800 900 1000
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1Acquisizione
Chip
Corr
ela
zio
ne
0 100 200 300 400 500 600 700 800 900 1000
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1Acquisizione
Chip
Corr
ela
zio
ne ∆∆tt
GPS SiS
GPS Signal at the receiver
Reciver Local Code
Shifted local code
GPS SiS reachs the reciver after dt delay
SUMMARY55
Code-phaseCode-phase
Search Space
1023 Chip
±10
KH
z
∆f = 500 Hz
∆τ = 1/fc ≈ 1μsFase Codice PRNF
req
. Do
pp
ler
SUMMARY66
MODULO ACQUISIZIONE
Hw-Based
1023 Chip
±10
KH
z
∆f = 500 Hz
∆τ = 1/fc ≈ 1μsPRN code phaseF
req
. Do
pp
ler
SUMMARY77
Sw-Based
1023 Chip
±10
KH
z
∆f = 500 Hz
∆τ = 1/fc ≈ 1μsPRN code phaseF
req
. Do
pp
ler
MODULO ACQUISIZIONESUMMARY88
Computational issues
Fast Fourier Transform Parallel Code Phase Search Acquisition Algorithm
with high computing efficiency
Parametric Acquisition Configurable time and frequency bin size Trade-off : accuracy and sensitivity versus computational weight
MODULO ACQUISIZIONESUMMARY99
Acquisition Module
MODULO ACQUISIZIONESUMMARY1010
Parametric GUI
MODULO ACQUISIZIONESUMMARY1111
MODULO ACQUISIZIONESUMMARY1212
SV N°22 SV N°2
Acquired SV
MODULO ACQUISIZIONESUMMARY1313
SV dynamicDoppler Shift (kHz)
-5
-4
-3
-2
-1
0
1
2
3
4
5
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
Sat.
MODULO ACQUISIZIONESUMMARY1414
Pseudorange (ms)
0
0,2
0,4
0,6
0,8
1
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
Sat.
MODULO ACQUISIZIONESUMMARY1515
Goals achieved: Implemented PRN Code generator
(test gold sequence properties) Acquisition module (Parametric function, FFT)
(testing with a Real digital GPS signal)
Future development: Tracking module Navigation solution module
MODULO ACQUISIZIONESUMMARY1616
