Post on 31-Mar-2015
transcript
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