Re: [Discuss-gnuradio] GPS Signals recorded IQ samples file

On Fri, Aug 21, 2015 at 8:41 PM, Francisco Albani <francisco.albani@gmail.com> wrote:

 

Marcus: I was not expecting to "see" the signal because I already knew it was under noise floor. My conclusion of "signal absence" was after my GPS receiver was not able to decode it when I replayed it with an USRP.

​If you replayed the capture file over the USRP for reception by a commercial GPS receiver, you'll have to carefully adjust the digital amplitude sent to the USRP and USRP PA gain setting in order to 1) transmit enough signal power, as the captured data typically has very low numerical values, and 2) avoid overloading the front end of the GPS receiver that is designed to work with low-level signals.

I've done this successfully in the past in building GPS interference mitigation applications.

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Johnathan Corgan
Corgan Labs - SDR Training and Development Services

Intro to SDR Class - Aug. 31-Sep. 1, Columbia, MD

Intro to SDR Class - Sep. 3-4, Santa Clara, CA
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