# GPS signal generator

**URL:** <https://www.ruby-forum.com/t/gps-signal-generator/240168>\
**Category:** GNU Radio\
**Created:** [March 31, 2014, 5:09pm UTC](https://www.ruby-forum.com/t/gps-signal-generator/240168 "2014-03-31T17:09:33Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\
**Post date:** [March 31, 2014, 5:09pm UTC](https://www.ruby-forum.com/t/gps-signal-generator/240168/1 "2014-03-31T17:09:33Z")

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Hello,

I am developing a GPS generator GRC. I use this block diagram:

[![](https://i1281.photobucket.com/albums/a515/Carlos_Alberto_Ruiz_Naranjo/GPS_zps3ce4af88.png) ](https://i1281.photobucket.com/albums/a515/Carlos_Alberto_Ruiz_Naranjo/GPS_zps3ce4af88.png)

- C / A code. 1023 Samples, Sample rate: 5.1151Msps, interpolation  
Repeat 5 → 977.5e-9 s each chip. (1,023 MHz)

- Navigation data. Sample rate: 5.1151Msps, Repeat interpolation:  
102302 → 0.02 s each chip. (50Hz)

But I have a question. The L1 signal is, so I do not use the P-Code.  
What should I use in the complex block? Any random source, a null  
constant source?

Is it right to my block diagram?

- My C / A code spectrum:  
[http://i1281.photobucket.com/albums/a515/Carlos\_Alberto\_Ruiz\_Naranjo/fft\_zps6d97a95d.png](http://i1281.photobucket.com/albums/a515/Carlos_Alberto_Ruiz_Naranjo/fft_zps6d97a95d.png)

\*\* My GPS signal autocorrelation:  
[![](https://i1281.photobucket.com/albums/a515/Carlos_Alberto_Ruiz_Naranjo/autocorrelation_zps70030f04.png) ](https://i1281.photobucket.com/albums/a515/Carlos_Alberto_Ruiz_Naranjo/autocorrelation_zps70030f04.png)

\*\*\* I DO NOT want to raise the frequency at 1575.42 MHz

Thank you! 🙂