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Receiving GPS signal in IIO

Hello

I have a GPS antenna SMA 50 Ohm connector that activates with a 3.3 v and i was wondering if there is any way i could connect it to my pluto and activate it in order to visualize the 1575.42 MHz on IIO? 

Thanks BR

Top Replies

  • You would need a Bias-T to power it with Pluto.

    -Travis

  • thank you Travis, i have found one that powers with a USB on the internet ill try it later

  • Hi Travis,

    I also encountered a similar problem when I attempted to acquire GPS signals using Pluto-SDR.

    I connected the active GPS antenna with Pluto-SDR, just like  did, configuring the frequency to 1575.42MHz,and the filter bandwidth to 1MHz, the sampling frequency to 5 MHz, then acquired the continous baseband I/Q samples using Matlab. But when I processing the samples, I could not find any GPS satellite signal in it. (The GPS signal processing program has been verified). I don't know why.

    You just mentioned that I need a Bias-T. What is the Bias-T,  why should I use it, and where can I buy it?

    Is there any other reasons why I can not find GPS satellite signal in the I/Q samples? Do I need  replace the TCXO in Pluto-SDR with a more stable one ?

    Thanks for your attention, and hopping for your reply.

  • (The GPS signal processing program has been verified). I don't know why.

    Have you verified that there is a signal present? Have you tried transmitting a test GPS waveform to recover?

    You just mentioned that I need a Bias-T. What is the Bias-T,  why should I use it, and where can I buy it?

    Many "powered" GPS antennas require power from the feed cable (usually an SMA) to provide the power to their amplifiers. A Bias-T injects this power by biasing the signal level by the required amplifier voltage.

    Is there any other reasons why I can not find GPS satellite signal in the I/Q samples? Do I need  replace the TCXO in Pluto-SDR with a more stable one ?

    This would depend on the pull-in range of your GPS receiver algorithm.

    -Travis

  • Thanks for your reply. I have verified that the gps signal is present. I used a dedicated GPS IF signal collector with the same active GPS antenna connected with it. When I accomplished the IF signal collection with this dedicated collector,  the GPS signal  can be detected by IF signal processing(i.e. signal acquisition and tracking). At present I haven‘t tried transmitting a test GPS wave form to recover. But it will be my future work. I have found some related program on the internet, and I will adapt them to Pluto after I  solve the above mentioned problem. I have understood the  function and application method of Bias-T, and I will buy it later. I will tell you the result after I finished the experiment. I will study the  necessity to replace the existing TCXO with a more accurate and stable one. But for signal acquisition phase( estimating  course  PRN code phase and carrier doppler of gps signal with open loop manner, the doppler frequency search range can be set optionally) , this problem can be ignored.