gps-sdr-sim
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osqzss
Problems getting devices to lock using Adalm-Pluto
Hi,
I'm having some trouble to get any tested device to lock on simulated location, using Adalm-Pluto:
Linux pluto 4.14.0-41915-gc2041af #279 SMP PREEMPT Mon Jan 14 13:13:47 CET 2019 armv7l GNU/Linux Machine model: Analog Devices PlutoSDR Rev.B (Z7010/AD9363)
File to be played:
pi@raspberrypi:~ $ ./gps-sdr-sim/gps-sdr-sim -e ./brdc.n -l 41.661636,-4.7446656,630 -t 2019/12/24,12:00:00 -o ./gpssim2.bin -s 10e6 -b 8 -v Using static location mode. 8.382e-09 -1.490e-08 -5.960e-08 1.192e-07 9.421e+04 -1.311e+05 -1.311e+05 8.520e+05 3.72529029846e-09 6.21724893790e-15 405504 2085 18 Start time = 2019/12/24,12:00:00 (2085:216000) Duration = 300.0 [sec] 02 221.6 30.5 22691094.9 3.7 05 304.7 66.5 20530759.3 2.2 06 185.6 9.3 24752200.0 6.5 07 53.0 46.3 21876248.5 2.8 09 79.7 11.2 24550751.8 5.9 13 274.8 39.4 21957357.0 3.0 15 274.5 7.6 24660240.1 5.2 28 141.6 15.4 23932301.2 5.8 30 103.4 75.9 20424508.4 2.1 Time into run = 30.0 02 221.4 30.3 22705012.0 3.7 05 304.5 66.8 20523720.9 2.2 06 185.5 9.1 24773209.5 6.6 07 52.9 46.1 21887898.0 2.8 09 79.9 11.1 24567389.4 5.9 13 275.0 39.6 21944882.8 3.0 15 274.6 7.8 24642381.9 5.2 28 141.4 15.6 23915663.7 5.7 30 102.4 75.9 20424895.2 2.1 Time into run = 60.0 02 221.3 30.1 22718988.0 3.7 05 304.3 67.0 20516768.1 2.2 06 185.5 8.9 24794211.0 6.6 07 52.8 45.9 21899612.3 2.8 09 80.0 10.9 24584032.7 5.9 13 275.2 39.7 21932449.8 2.9 15 274.8 7.9 24624533.9 5.1 28 141.3 15.8 23899048.3 5.7 30 101.4 75.8 20425381.8 2.1 Time into run = 63.8 ^C
Playing the file: pi@raspberrypi:~ $ ./gps-sdr-sim/player/plutoplayer -t ./gpssim2.bin
Transmit file size: 1.187 GB Acquiring IIO context Found (Analog Devices Inc. PlutoSDR (ADALM-PLUTO)) Acquiring devices Context has 5 device(s). Acquiring TX device Initializing streaming channels Enabling IIO streaming channels Creating TX buffer Transmit starts... Done.
Taking a look ./retrogram-plutosdr --rate 5e6 --bw 3e6 --freq 1575.42e6 --step 0.01e6 --ref-lvl 0 --uri usb:1.7.5 ( no profile change)
Also, getting no locks either when using other software: pi@raspberrypi:~ $ pluto-gps-sim/pluto-gps-sim -e ./brdc.n -B 3.0 -A -30 -l 41.661636,-4.7446656,0 -U usb:1.7.5 -t 2019/12/24,12:00:00 -v Using static location mode. 8.382e-09 -1.490e-08 -5.960e-08 1.192e-07 9.421e+04 -1.311e+05 -1.311e+05 8.520e+05 3.72529029846e-09 6.21724893790e-15 405504 2085 18 Gain: -30.0dB RINEX date = 24-DEC-19 06:42 Start time = 2019/12/24,12:00:00 (2085:216000) PRN Az El Range Iono 02 221.6 30.5 22691415.0 3.7 05 304.7 66.5 20531337.2 2.2 06 185.6 9.3 24752301.5 6.5 07 53.0 46.3 21876703.7 2.8 09 79.7 11.2 24550874.3 5.9 13 274.8 39.4 21957756.8 3.0 15 274.5 7.6 24660323.6 5.2 28 141.6 15.4 23932468.9 5.8 30 103.4 75.9 20425119.5 2.1
I'm stumped,... any help would be greatly appreciated.
Cheers!
I assume with device you mean a mobile. Are you aware that on modern mobile device GPS is only one of several services to obtain the device location. Also, real GPS has very low guaranteed signal strength everywhere on earth. Your device may include jamming detection by strong signals and therefore doesn't consider the Pluto signal being valid.
I've the same issue. But then my attenuation is higher than -55.0 dB, the regular GPS-signals get jammed. And as far as i know, my mobile has no jamming detection.
Try turning off your pluto's xo_correction (fw_setenv xo_correction 40000000 on console), and use a baseband data rate of 4 MHz. Set the attenuation to 80 dB, and put the receiver within 30 cm of the pluto.
I am not getting a position fix with the PLUTO SDR card, I have generated a signal with a -100dbm signal power using PLUTO SDR and fed to U-Blox8 GNSS Receiver, satelliteS are acquired but their C/N Ratios are changes gradually i.e. not constant C/N ratio, I am getting position fix and gone
can you help me out to resolve the issue
Try this .grc file in gnuradio companion. You need to disable xo_correction on your Pluto, then tweak the value in the ppmOutTarget variable of the grc file.
thank you so much for your response,
I am not using gnu radio, I am having plutoplayer.c code which is linux compatible, using this plutoplayer.c code I am generating RF signal by following the commands in gps-sdr-sim.zip file
please helpme out to resolve the issue
I suggest you install gnuradio. Disabling xo_correction will probably be enough though, so long as your GPS receiver can tune in the remaining ppm on its own.
is there any other way to solve this problem?
On Tue, Mar 9, 2021 at 10:26 AM jamesl-dm [email protected] wrote:
I suggest you install gnuradio. Disabling xo_correction will probably be enough though, so long as your GPS receiver can tune in the remaining ppm on its own.
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fw_setenv xo_correction 40000000
This will not turn off XO correction but overwrites the factory calibration value of the oscillator. Keep in mind: The output frequency will be generated by multiplication from reference frequency (40000000 Hz). Any offset in reference will be multiplied at the output. Setting 4000000 Hz as (assumed) fix reference might create a difference to the real TCXO/OCXO frequency. This difference is then multiplied and a visible offset at 1575 MHz.
My two Pluto using 40000017 and 40000004 to create a precise output at 1575.42 MHz.
The issue is, if you use the xo_correction the relationship between the RF center frequency and the baseband sample rate gets recalculated and quantized according to a complex algorithm in the Pluto driver. And if you're unlucky, the quantized values will be so far off that the baseband sample rate will slip in and out of phase coherence with what the GPS receiver is expecting based on the center frequency. This causes the signal strengths reported by the receiver to oscillate, and the receiver loses lock. So my solution is to set xo_correction to nominal, and account for the quantization and ppm correction in software. You even have to account for the gnuradio resampler block quantizing its arguments into a single precision float - the GPS receiver is that sensitive!
Hello James,
Earlier I have Generated GPS signal samples with 2.6MHz sampling frequency using Pluto SDR, with that sampling frequency satellite C/N ratios are oscillates very frequently in GNSS Receiver
Later I have changed sampling frequency to 2.5MHz with this sampling frequency I am getting constant 2D fix in GNSS Receiver, I am not getting 3D fix
I have done nothing regarding xo_correction for Pluto in GNU radio
On Wed, Mar 10, 2021, 07:13 jamesl-dm [email protected] wrote:
The issue is, if you use the xo_correction the relationship between the RF center frequency and the baseband sample rate gets recalculated and quantized according to a complex algorithm in the Pluto driver. And if you're unlucky, the quantized values will be so far off that the baseband sample rate will slip in and out of phase coherence with what the GPS receiver is expecting based on the center frequency. This causes the signal strengths reported by the receiver to oscillate, and the receiver loses lock. So my solution is to set xo_correction to nominal, and account for the quantization and ppm correction in software. You even have to account for the gnuradio resampler block quantizing its arguments into a single precision float - the GPS receiver is that sensitive!
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The .grc file I posted is configured for a 4 MHz sample rate, and the xo_correction set to 40000000. That's all the help I can offer - I'm unsubscribing from this thread now.
Dear james and mictronics,
i have modified xo_correction to 40MHz of pluto sdr in config.txt file which was given by pluto SDR mass storage
[image: image.png]
GPS IQ Samples Generation: [image: image.png]
U-blox GNSS receiver Results: [image: image.png] i am getting constant 2D fix, i am not getting 3D fix , can you help me out where is the issue.
On Wed, Mar 10, 2021 at 8:37 AM jamesl-dm @.***> wrote:
The .grc file I posted is configured for a 4 MHz sample rate, and the xo_correction set to 40000000. That's all the help I can offer - I'm unsubscribing from this thread now.
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In u-center open message view (F9), check if your receiver supports UBX-RXM-MEASX message. In case yes, check that MP is indicated low or medium for the simulated satellites. When MP is high increase the attenuation (-a option). You can also check the UBX-MON-HW message. Noise level should be as low as possible, same for CW jamming indicator. AGC somewhere in the middle.
What is your setup? Is that a direct cable connection or via antenna?
Thanks for your reply,
Pluto SDR TX is connected to Ublox receiver with -90dbm attentuation (-50dbm as Pluto attentuation and -40 external attentuator)
I have Generated 12 satellites out of 12 I am getting atmost 5-6 only and I am not getting 3D-fix
Is there any hardaware/configurations modifications still I need to do further, I have generated GPS IQ streams from GPS-SDR-SIM with 2.5Msps sampling rate.
Please share your views for getting proper 3D fix with Pluto SDR
On Thu, Mar 18, 2021, 20:28 Mictronics @.***> wrote:
In u-center open message view (F9), check if your receiver supports UBX-RXM-MEASX message. In case yes, check that MP is indicated low or medium for the simulated satellites. When MP is high increase the attenuation (-a option). You can also check the UBX-MON-HW message. Noise level should be as low as possible, same for CW jamming indicator. AGC somewhere in the middle.
What is your setup? Is that a direct cable connection or via antenna?
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Code: https://github.com/Mictronics/multi-sdr-gps-sim
Setup PlutoSdr (with OCXO) -> 10dB attenuator -> ublox M8T
Commandline: gps-sim -g-80 -f -l -12.0,-16.0,400 -e rinex2.gz -snow -v --radio=plutosdr
Ephemeris and almanac for all satellites
Thanks for your response.
I will try with above mentioned procedure
Only concern is for me I have done nothing regarding TCXO modification of Pluto SDR.
On Fri, Mar 19, 2021, 01:26 Mictronics @.***> wrote:
[image: 1] https://user-images.githubusercontent.com/11965780/111688031-4fe04080-882b-11eb-9986-a37e48556ebe.png [image: image] https://user-images.githubusercontent.com/11965780/111688174-671f2e00-882b-11eb-8a93-5f5e32374ce2.png Code: https://github.com/Mictronics/multi-sdr-gps-sim Setup PlutoSdr (with OCXO) -> 10dB attenuator -> ublox M8T Commandline: gps-sim -g-80 -f -l -12.0,-16.0,400 -e rinex2.gz -snow -v --radio=plutosdr
Ephemeris and almanac for all satellites [image: image] https://user-images.githubusercontent.com/11965780/111689310-28d63e80-882c-11eb-89e0-5fd07e05cded.png
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Dear mictronics,
I have followed the procedure as you mentioned in the mail, my pluto SDR device is not recognized, please go through the below screenshots once.
gps-sim Executable_Creation: [image: image.png]
running command: [image: image.png]
TUI terminal Screenshots:
[image: image.png] [image: image.png] [image: image.png] [image: image.png]
what should i modify please let me knoww
On Fri, Mar 19, 2021 at 1:26 AM Mictronics @.***> wrote:
[image: 1] https://user-images.githubusercontent.com/11965780/111688031-4fe04080-882b-11eb-9986-a37e48556ebe.png [image: image] https://user-images.githubusercontent.com/11965780/111688174-671f2e00-882b-11eb-8a93-5f5e32374ce2.png Code: https://github.com/Mictronics/multi-sdr-gps-sim Setup PlutoSdr (with OCXO) -> 10dB attenuator -> ublox M8T Commandline: gps-sim -g-80 -f -l -12.0,-16.0,400 -e rinex2.gz -snow -v --radio=plutosdr
Ephemeris and almanac for all satellites [image: image] https://user-images.githubusercontent.com/11965780/111689310-28d63e80-882c-11eb-89e0-5fd07e05cded.png
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small modification,
i am using this command:
gps-sim -g-80 -f -l -12.0,-16.0,400 -e rinex2.gz -snow -v --radio=plutosdr
On Sat, Mar 20, 2021 at 1:15 PM Kintada Atchyutarao < @.***> wrote:
Dear mictronics,
I have followed the procedure as you mentioned in the mail, my pluto SDR device is not recognized, please go through the below screenshots once.
gps-sim Executable_Creation: [image: image.png]
running command: [image: image.png]
TUI terminal Screenshots:
[image: image.png] [image: image.png] [image: image.png] [image: image.png]
what should i modify please let me knoww
On Fri, Mar 19, 2021 at 1:26 AM Mictronics @.***> wrote:
[image: 1] https://user-images.githubusercontent.com/11965780/111688031-4fe04080-882b-11eb-9986-a37e48556ebe.png [image: image] https://user-images.githubusercontent.com/11965780/111688174-671f2e00-882b-11eb-8a93-5f5e32374ce2.png Code: https://github.com/Mictronics/multi-sdr-gps-sim Setup PlutoSdr (with OCXO) -> 10dB attenuator -> ublox M8T Commandline: gps-sim -g-80 -f -l -12.0,-16.0,400 -e rinex2.gz -snow -v --radio=plutosdr
Ephemeris and almanac for all satellites [image: image] https://user-images.githubusercontent.com/11965780/111689310-28d63e80-882c-11eb-89e0-5fd07e05cded.png
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I have attached screenshots in an earlier mail, for your reference I am sending again
On Fri, Mar 19, 2021 at 1:26 AM Mictronics @.***> wrote:
[image: 1] https://user-images.githubusercontent.com/11965780/111688031-4fe04080-882b-11eb-9986-a37e48556ebe.png [image: image] https://user-images.githubusercontent.com/11965780/111688174-671f2e00-882b-11eb-8a93-5f5e32374ce2.png Code: https://github.com/Mictronics/multi-sdr-gps-sim Setup PlutoSdr (with OCXO) -> 10dB attenuator -> ublox M8T Commandline: gps-sim -g-80 -f -l -12.0,-16.0,400 -e rinex2.gz -snow -v --radio=plutosdr
Ephemeris and almanac for all satellites [image: image] https://user-images.githubusercontent.com/11965780/111689310-28d63e80-882c-11eb-89e0-5fd07e05cded.png
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gps-sim Executable_Creation:
[image: image.png]
running command:
[image: image.png]
TUI terminal Screenshots:
[image: image.png]
[image: image.png]
[image: image.png]
[image: image.png]
No images....
can you help me out faster, i have tucked with PLUTO SDR since 15-20 days
Everyone wants everything faster. Complain when you work 15-20 month on this.
PFA,
On Sat, Mar 20, 2021, 22:40 Mictronics @.***> wrote:
gps-sim Executable_Creation: [image: image.png]
running command: [image: image.png]
TUI terminal Screenshots:
[image: image.png] [image: image.png] [image: image.png] [image: image.png]
No images....
can you help me out faster, i have tucked with PLUTO SDR since 15-20 days Everyone wants everything faster. Complain when you work 15-20 month on this.
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hi Micronics,
have you received Images??
On Sat, Mar 20, 2021 at 10:52 PM Kintada Atchyutarao < @.***> wrote:
PFA,
On Sat, Mar 20, 2021, 22:40 Mictronics @.***> wrote:
gps-sim Executable_Creation: [image: image.png]
running command: [image: image.png]
TUI terminal Screenshots:
[image: image.png] [image: image.png] [image: image.png] [image: image.png]
No images....
can you help me out faster, i have tucked with PLUTO SDR since 15-20 days Everyone wants everything faster. Complain when you work 15-20 month on this.
— You are receiving this because you commented. Reply to this email directly, view it on GitHub https://github.com/osqzss/gps-sdr-sim/issues/225#issuecomment-803420523, or unsubscribe https://github.com/notifications/unsubscribe-auth/ATEFFY55F3THE4GIVJMEWXDTETJHZANCNFSM4J7J4FKQ .
Received? No. What's the problem with attaching them to this PR? Simple copy and past or upload works for me. Maybe you stop quote reply.
No I am sending again for you...but I don't know what's happening, it's ok again I will send you
On Mon, Mar 22, 2021, 19:15 Mictronics @.***> wrote:
Received? No. What's the problem with attaching them to this PR? Simple copy and past or upload works for me. Maybe you stop quote reply.
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You just reply to notification Emails from Github, right? Did you check where that goes? I guess you can send your images a hundred times, they will not care. m(
