SOURCEFORGE » RALF » 2015 Software defined GPS receiver

h1. PART 5 : Implementation.

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h2. 1 - Starting point.

h3. a - Receiver scheme and milestones.

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h3. b - Quid about LabVIEW.

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Input : GPS signal of sampling frequency 38.192 MHz at intermediate frequency 9.55 MHz from CD *[1]* under GNSS_signal_records/GPSdata-DiscreteComponents-fs38_192-if9_55.bin

h3. c - Local C/A code generation.

Generation : _CA_code.vi_ with subVI _CA_generatorG1.vi_ _CA_generatorG2.vi_

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h2. 2 - Acquisition.

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h2. 3 - Tracking.

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p=. !TrackingMin.PNG!

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h2. 4 - Navigation Data decoding.

*See the UML Diagram of Section 4 under :* attachment:"NavigationData.PNG".

h3. a - Delimiting subframes.

The files involved are :
- _FindPreamble.vi_
- _TestFindPreamble.vi_
- _GenerateFrame.vi_
- _ParityCheck.vi_

p=. !Preamble1.PNG! !Preamble2.PNG!

p((((. *Figure 5. :* Cross-correlation between navigation frame and local preamble. *Figure 5. :* Subframes with index of delimitation.



h3. b- Decoding ephemeris and information within the frame.

The files involved are :
- _Ephemeris.vi_
- _BinaryArrayToDecimal.vi_
- _twosComp2dec.vi_
- _ParityCheck.vi_
- _TestEphemeris.vi_

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h2. 5 - Localization computation.

*See the UML Diagram of Section 5 under :* attachment:"Localization.PNG"

h3. a - Satellite position.

The files involved are :
- _SatellitePosition.vi_
- _TestSatellitePosition.vi_
- _Check_time.vi_

p=. !SatPos.PNG!
*Figure 5. :* Interface with ephemeris as input and illustration of the satellite position.

h3. b - Pseudoranges.

The file involved is :
_PseudorangesComputation.vi_

h3. c - Least Square solution for position determination.

The files involved are :
- _LeastSquarePosition.vi_
- _SatelliteRotationECEF.vi_
- _toTopocentric.vi_
- _CartesianToGeodetic.vi_
- _TroposphericCorrection.vi_

h2. 6 - Complete UML Diagram of the receiver.

!UMLDiagram.png!

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*References :*
*[1]* K. Borre, D. M. Akos, N. Bertelsen, P. Rinder, S. H. Jensen, A software-defined GPS and GALILEO receiver