Hello, I have been struggling with a trying to acquire GPS with an N210 for some time now as was wondering if anyone could help me out. My setup is as follows:
GPS antenna + T bias with 3.3 V DC power, RF input connected to RX1/TX1 of USRP I used this setup with a pmod GPS receiver was able to acquire latitude / longitude measurements almost instantly. So I am pretty sure it is not the external hardware (antenna, power supply, cabling, etc). When connecting the antenna to the USRP Rx1, I run the code at this link https://gnss-sdr.org/conf . Below is what I get in the terminal log. There are several errors/warnings. I tried to remove the "thread priority" warning using by adding @brian - rtprio 99 to the limits.conf file but that did not remove the warning. It is possible I did not put in the right group name or enter the command properly into the file. I also tried modifying the buffer settings so I could have more items of less size. I used various send rcvr commands for this but I still had the "4 items of 3200" statement in every trial. Lastly I was able to remove the "decimation is odd" warning by increasing the singal sample rate to 10 MHz and reducing filter bandwidth to 400 kHz. This still did not help me obtain a Lat/Long measurement. I think I have issues with buffering/sampling because the I cannot maintain lock on multiple satellites for an extended period of time. Any help would be greatly appreciated. I am relatively new to Linux but I wanted to see if I could get this to work. Thank you, Brian Terminal Log : brian@MSI-ThinkPad-P51:~/gnss_sdr$ gnss-sdr --config_file=./my_GPS_receiver.conflinux; GNU C++ version 7.3.0; Boost_106501; UHD_003.010.003.000-0-unknown Initializing GNSS-SDR v0.0.9 ... Please wait. Logging will be done at "/tmp" Use gnss-sdr --log_dir=/path/to/log to change that. -- Opening a USRP2/N-Series device... -- Current recv frame size: 1472 bytes -- Current send frame size: 1472 bytes UHD Warning: Unable to set the thread priority. Performance may be negatively affected. Please see the general application notes in the manual for instructions. EnvironmentError: OSError: error in pthread_setschedparam UHD Warning: The requested decimation is odd; the user should expect CIC rolloff. Select an even decimation to ensure that a halfband filter is enabled. decimation = dsp_rate/samp_rate -> 25 = (100.000000 MHz)/(4.000000 MHz) Sampling Rate for the USRP device: 4000000.000000 [sps]... UHD RF CHANNEL #0 SETTINGS Actual USRP center freq.: 1575420000.010133 [Hz]... PLL Frequency tune error 0.010133 [Hz]... Actual daughterboard gain set to: 38.000000 dB... Setting RF bandpass filter bandwidth to: 2000000.000000 [Hz]... Check for front-end LO: locked ... is Locked Starting a TCP Server on port 2101 The TCP Server is up and running. Accepting connections ... UHD Warning: The requested decimation is odd; the user should expect CIC rolloff. Select an even decimation to ensure that a halfband filter is enabled. decimation = dsp_rate/samp_rate -> 25 = (100.000000 MHz)/(4.000000 MHz) ^C brian@MSI-ThinkPad-P51:~/gnss_sdr$ gnss-sdr --config_file=./my_GPS_receiver.conflinux; GNU C++ version 7.3.0; Boost_106501; UHD_003.010.003.000-0-unknown Initializing GNSS-SDR v0.0.9 ... Please wait. Logging will be done at "/tmp" Use gnss-sdr --log_dir=/path/to/log to change that. -- Opening a USRP2/N-Series device... -- Current recv frame size: 1472 bytes -- Current send frame size: 1472 bytes UHD Warning: Unable to set the thread priority. Performance may be negatively affected. Please see the general application notes in the manual for instructions. EnvironmentError: OSError: error in pthread_setschedparam UHD Warning: The requested decimation is odd; the user should expect CIC rolloff. Select an even decimation to ensure that a halfband filter is enabled. decimation = dsp_rate/samp_rate -> 25 = (100.000000 MHz)/(4.000000 MHz) Sampling Rate for the USRP device: 4000000.000000 [sps]... UHD RF CHANNEL #0 SETTINGS Actual USRP center freq.: 1575420000.010133 [Hz]... PLL Frequency tune error 0.010133 [Hz]... Actual daughterboard gain set to: 38.000000 dB... Setting RF bandpass filter bandwidth to: 2000000.000000 [Hz]... Check for front-end LO: locked ... is Locked Starting a TCP Server on port 2101 The TCP Server is up and running. Accepting connections ... gr::buffer::allocate_buffer: warning: tried to allocate 4 items of size 32000. Due to alignment requirements 16 were allocated. If this isn't OK, consider padding your structure to a power-of-two bytes. On this platform, our allocation granularity is 4096 bytes. gr::buffer::allocate_buffer: warning: tried to allocate 4 items of size 32000. Due to alignment requirements 16 were allocated. If this isn't OK, consider padding your structure to a power-of-two bytes. On this platform, our allocation granularity is 4096 bytes. gr::buffer::allocate_buffer: warning: tried to allocate 4 items of size 32000. Due to alignment requirements 16 were allocated. If this isn't OK, consider padding your structure to a power-of-two bytes. On this platform, our allocation granularity is 4096 bytes. gr::buffer::allocate_buffer: warning: tried to allocate 4 items of size 32000. Due to alignment requirements 16 were allocated. If this isn't OK, consider padding your structure to a power-of-two bytes. On this platform, our allocation granularity is 4096 bytes. gr::buffer::allocate_buffer: warning: tried to allocate 4 items of size 32000. Due to alignment requirements 16 were allocated. If this isn't OK, consider padding your structure to a power-of-two bytes. On this platform, our allocation granularity is 4096 bytes. gr::buffer::allocate_buffer: warning: tried to allocate 4 items of size 32000. Due to alignment requirements 16 were allocated. If this isn't OK, consider padding your structure to a power-of-two bytes. On this platform, our allocation granularity is 4096 bytes. gr::buffer::allocate_buffer: warning: tried to allocate 4 items of size 32000. Due to alignment requirements 16 were allocated. If this isn't OK, consider padding your structure to a power-of-two bytes. On this platform, our allocation granularity is 4096 bytes. gr::buffer::allocate_buffer: warning: tried to allocate 4 items of size 32000. Due to alignment requirements 16 were allocated. If this isn't OK, consider padding your structure to a power-of-two bytes. On this platform, our allocation granularity is 4096 bytes. UHD Warning: The requested decimation is odd; the user should expect CIC rolloff. Select an even decimation to ensure that a halfband filter is enabled. decimation = dsp_rate/samp_rate -> 25 = (100.000000 MHz)/(4.000000 MHz) Tracking start on channel 0 for satellite GPS PRN 09 (Block IIF) Tracking start on channel 1 for satellite GPS PRN 18 (Block IIR) Tracking start on channel 2 for satellite GPS PRN 07 (Block IIR-M) Current input signal time = 1 [s] Tracking start on channel 3 for satellite GPS PRN 31 (Block IIR-M) Loss of lock in channel 1! Current input signal time = 2 [s] Loss of lock in channel 2! Tracking start on channel 4 for satellite GPS PRN 15 (Block IIR-M) Tracking start on channel 1 for satellite GPS PRN 16 (Block IIR) Current input signal time = 3 [s] Loss of lock in channel 3! Current input signal time = 4 [s] Tracking start on channel 2 for satellite GPS PRN 12 (Block IIR-M) Loss of lock in channel 1! Loss of lock in channel 4! Current input signal time = 5 [s] Current input signal time = 6 [s] Current input signal time = 7 [s] Current input signal time = 8 [s] Tracking start on channel 3 for satellite GPS PRN 07 (Block IIR-M) Current input signal time = 9 [s] Tracking start on channel 1 for satellite GPS PRN 06 (Block IIF) Current input signal time = 10 [s] Loss of lock in channel 3! Loss of lock in channel 1! Tracking start on channel 4 for satellite GPS PRN 07 (Block IIR-M) Current input signal time = 11 [s] Current input signal time = 12 [s] Loss of lock in channel 4! Current input signal time = 13 [s] Current input signal time = 14 [s] Tracking start on channel 1 for satellite GPS PRN 26 (Block IIF) Current input signal time = 15 [s] Current input signal time = 16 [s] NAV Message: received subframe 1 from satellite GPS PRN 09 (Block IIF) Tracking start on channel 3 for satellite GPS PRN 10 (Block IIF) Tracking start on channel 4 for satellite GPS PRN 23 (Block IIR) Loss of lock in channel 1! Tracking start on channel 5 for satellite GPS PRN 14 (Block IIR) Current input signal time = 17 [s] Loss of lock in channel 3! Tracking start on channel 1 for satellite GPS PRN 06 (Block IIF) Loss of lock in channel 4! Current input signal time = 18 [s] Loss of lock in channel 5! Tracking start on channel 3 for satellite GPS PRN 30 (Block IIF) Current input signal time = 19 [s] Loss of lock in channel 1! Loss of lock in channel 3! Current input signal time = 20 [s] Tracking start on channel 4 for satellite GPS PRN 20 (Block IIR) Current input signal time = 21 [s] Tracking start on channel 1 for satellite GPS PRN 04 (Block Unknown) Current input signal time = 22 [s] NAV Message: received subframe 2 from satellite GPS PRN 09 (Block IIF) Loss of lock in channel 4! Tracking start on channel 3 for satellite GPS PRN 10 (Block IIF) Current input signal time = 23 [s] Tracking start on channel 4 for satellite GPS PRN 31 (Block IIR-M) Tracking start on channel 5 for satellite GPS PRN 21 (Block IIR) Loss of lock in channel 1! Tracking start on channel 6 for satellite GPS PRN 30 (Block IIF) Loss of lock in channel 3! Current input signal time = 24 [s] Loss of lock in channel 4! Loss of lock in channel 5! Current input signal time = 25 [s] Loss of lock in channel 6! Current input signal time = 26 [s] Tracking start on channel 1 for satellite GPS PRN 13 (Block IIR) Tracking start on channel 3 for satellite GPS PRN 25 (Block IIF) Tracking start on channel 4 for satellite GPS PRN 23 (Block IIR) Current input signal time = 27 [s] Tracking start on channel 5 for satellite GPS PRN 20 (Block IIR) Tracking start on channel 6 for satellite GPS PRN 32 (Block IIF) Loss of lock in channel 1! Loss of lock in channel 3! Tracking start on channel 7 for satellite GPS PRN 18 (Block IIR) Current input signal time = 28 [s] NAV Message: received subframe 3 from satellite GPS PRN 09 (Block IIF) Loss of lock in channel 5! Loss of lock in channel 4! Tracking start on channel 1 for satellite GPS PRN 25 (Block IIF) Loss of lock in channel 6! Current input signal time = 29 [s] Loss of lock in channel 7! Tracking start on channel 3 for satellite GPS PRN 16 (Block IIR) Current input signal time = 30 [s] Loss of lock in channel 1! Current input signal time = 31 [s] Loss of lock in channel 3! Tracking start on channel 4 for satellite GPS PRN 01 (Block IIF) Tracking start on channel 1 for satellite GPS PRN 02 (Block IIR) Current input signal time = 32 [s] Tracking start on channel 3 for satellite GPS PRN 21 (Block IIR) Current input signal time = 33 [s] Loss of lock in channel 4! Loss of lock in channel 1! Current input signal time = 34 [s] Loss of lock in channel 3! NAV Message: received subframe 4 from satellite GPS PRN 12 (Block IIR-M) NAV Message: received subframe 4 from satellite GPS PRN 09 (Block IIF) Tracking start on channel 5 for satellite GPS PRN 26 (Block IIF) Current input signal time = 35 [s] Current input signal time = 36 [s] Loss of lock in channel 5! Tracking start on channel 1 for satellite GPS PRN 32 (Block IIF) Tracking start on channel 3 for satellite GPS PRN 03 (Block IIF) Current input signal time = 37 [s] Current input signal time = 38 [s] Tracking start on channel 4 for satellite GPS PRN 26 (Block IIF) Loss of lock in channel 1! Tracking start on channel 5 for satellite GPS PRN 20 (Block IIR) Loss of lock in channel 3! Current input signal time = 39 [s] Tracking start on channel 1 for satellite GPS PRN 21 (Block IIR) Loss of lock in channel 4! Current input signal time = 40 [s] Tracking start on channel 3 for satellite GPS PRN 07 (Block IIR-M) NAV Message: received subframe 5 from satellite GPS PRN 12 (Block IIR-M) NAV Message: received subframe 5 from satellite GPS PRN 09 (Block IIF) Loss of lock in channel 5! Loss of lock in channel 1! Current input signal time = 41 [s] Tracking start on channel 4 for satellite GPS PRN 26 (Block IIF) Current input signal time = 42 [s] Loss of lock in channel 3! Current input signal time = 43 [s] Tracking start on channel 1 for satellite GPS PRN 07 (Block IIR-M) Loss of lock in channel 4! Current input signal time = 44 [s] Tracking start on channel 3 for satellite GPS PRN 02 (Block IIR) Current input signal time = 45 [s] Tracking start on channel 4 for satellite GPS PRN 21 (Block IIR) Loss of lock in channel 1! Current input signal time = 46 [s] Loss of lock in channel 3! NAV Message: received subframe 1 from satellite GPS PRN 12 (Block IIR-M) NAV Message: received subframe 1 from satellite GPS PRN 09 (Block IIF) Tracking start on channel 5 for satellite GPS PRN 17 (Block IIR-M) Tracking start on channel 1 for satellite GPS PRN 24 (Block IIF) Tracking start on channel 3 for satellite GPS PRN 18 (Block IIR) Loss of lock in channel 4! Current input signal time = 47 [s] Tracking start on channel 6 for satellite GPS PRN 30 (Block IIF) Tracking start on channel 4 for satellite GPS PRN 15 (Block IIR-M) Tracking start on channel 7 for satellite GPS PRN 16 (Block IIR) Current input signal time = 48 [s] Loss of lock in channel 1! Loss of lock in channel 5! Loss of lock in channel 3! Loss of lock in channel 4! Loss of lock in channel 7! Current input signal time = 49 [s] Loss of lock in channel 6! Current input signal time = 50 [s] Tracking start on channel 1 for satellite GPS PRN 06 (Block IIF) Tracking start on channel 3 for satellite GPS PRN 18 (Block IIR) Current input signal time = 51 [s] Tracking start on channel 4 for satellite GPS PRN 08 (Block IIF) Loss of lock in channel 1! Current input signal time = 52 [s] Tracking start on channel 5 for satellite GPS PRN 25 (Block IIF) NAV Message: received subframe 2 from satellite GPS PRN 12 (Block IIR-M) NAV Message: received subframe 2 from satellite GPS PRN 09 (Block IIF) Tracking start on channel 1 for satellite GPS PRN 21 (Block IIR) Loss of lock in channel 3! Loss of lock in channel 4! Current input signal time = 53 [s] Tracking start on channel 6 for satellite GPS PRN 10 (Block IIF) Loss of lock in channel 5! Tracking start on channel 3 for satellite GPS PRN 01 (Block IIF) Loss of lock in channel 1! Tracking start on channel 4 for satellite GPS PRN 24 (Block IIF) Current input signal time = 54 [s] Tracking start on channel 1 for satellite GPS PRN 32 (Block IIF) Loss of lock in channel 6! Current input signal time = 55 [s] Loss of lock in channel 4! Loss of lock in channel 3! Tracking start on channel 5 for satellite GPS PRN 23 (Block IIR) Current input signal time = 56 [s] Loss of lock in channel 1! Tracking start on channel 3 for satellite GPS PRN 30 (Block IIF) Current input signal time = 57 [s] Loss of lock in channel 5! Current input signal time = 58 [s] Loss of lock in channel 3! NAV Message: received subframe 3 from satellite GPS PRN 12 (Block IIR-M) NAV Message: received subframe 3 from satellite GPS PRN 09 (Block IIF) Current input signal time = 59 [s] Tracking start on channel 1 for satellite GPS PRN 13 (Block IIR) Tracking start on channel 3 for satellite GPS PRN 30 (Block IIF) Current input signal time = 60 [s] Loss of lock in channel 1! Current input signal time = 61 [s] Loss of lock in channel 3! Tracking start on channel 4 for satellite GPS PRN 17 (Block IIR-M) Current input signal time = 62 [s] Current input signal time = 63 [s] Tracking start on channel 1 for satellite GPS PRN 07 (Block IIR-M) Loss of lock in channel 4! Current input signal time = 64 [s] Tracking start on channel 3 for satellite GPS PRN 18 (Block IIR) NAV Message: received subframe 4 from satellite GPS PRN 12 (Block IIR-M) NAV Message: received subframe 4 from satellite GPS PRN 09 (Block IIF) Tracking start on channel 4 for satellite GPS PRN 26 (Block IIF) Tracking start on channel 5 for satellite GPS PRN 10 (Block IIF) Loss of lock in channel 1! Current input signal time = 65 [s] Loss of lock in channel 5! Loss of lock in channel 4! Loss of lock in channel 3! Tracking start on channel 6 for satellite GPS PRN 26 (Block IIF) Current input signal time = 66 [s] Tracking start on channel 1 for satellite GPS PRN 13 (Block IIR) Tracking start on channel 3 for satellite GPS PRN 02 (Block IIR) Current input signal time = 67 [s] Loss of lock in channel 6! Tracking start on channel 4 for satellite GPS PRN 18 (Block IIR) Loss of lock in channel 1! Current input signal time = 68 [s] Loss of lock in channel 3! Current input signal time = 69 [s] Loss of lock in channel 4! Current input signal time = 70 [s] Tracking start on channel 5 for satellite GPS PRN 28 (Block IIR) NAV Message: received subframe 5 from satellite GPS PRN 12 (Block IIR-M) NAV Message: received subframe 5 from satellite GPS PRN 09 (Block IIF) Current input signal time = 71 [s] Loss of lock in channel 5! Current input signal time = 72 [s] Tracking start on channel 1 for satellite GPS PRN 26 (Block IIF) Current input signal time = 73 [s] Tracking start on channel 3 for satellite GPS PRN 11 (Block IIR) Tracking start on channel 4 for satellite GPS PRN 05 (Block IIR-M) Tracking start on channel 5 for satellite GPS PRN 10 (Block IIF) Current input signal time = 74 [s] Loss of lock in channel 1! Current input signal time = 75 [s] Loss of lock in channel 3! Loss of lock in channel 4! Loss of lock in channel 5! Tracking start on channel 6 for satellite GPS PRN 26 (Block IIF) Tracking start on channel 1 for satellite GPS PRN 27 (Block IIF) Current input signal time = 76 [s] NAV Message: received subframe 1 from satellite GPS PRN 12 (Block IIR-M) NAV Message: received subframe 1 from satellite GPS PRN 09 (Block IIF) Loss of lock in channel 1! Current input signal time = 77 [s] Loss of lock in channel 6! Current input signal time = 78 [s] Tracking start on channel 3 for satellite GPS PRN 26 (Block IIF) Current input signal time = 79 [s] Tracking start on channel 1 for satellite GPS PRN 23 (Block IIR) Current input signal time = 80 [s] Loss of lock in channel 3! Current input signal time = 81 [s] Tracking start on channel 4 for satellite GPS PRN 15 (Block IIR-M) Loss of lock in channel 1! Current input signal time = 82 [s] NAV Message: received subframe 2 from satellite GPS PRN 12 (Block IIR-M) NAV Message: received subframe 2 from satellite GPS PRN 09 (Block IIF) Loss of lock in channel 4! Current input signal time = 83 [s] Current input signal time = 84 [s] Current input signal time = 85 [s] Tracking start on channel 3 for satellite GPS PRN 05 (Block IIR-M) Tracking start on channel 1 for satellite GPS PRN 28 (Block IIR) Tracking start on channel 4 for satellite GPS PRN 26 (Block IIF) Current input signal time = 86 [s] Tracking start on channel 5 for satellite GPS PRN 01 (Block IIF) Loss of lock in channel 3! Current input signal time = 87 [s] Tracking start on channel 6 for satellite GPS PRN 24 (Block IIF) Tracking start on channel 3 for satellite GPS PRN 13 (Block IIR) Loss of lock in channel 1! Loss of lock in channel 5! Loss of lock in channel 4! Tracking start on channel 7 for satellite GPS PRN 04 (Block Unknown) gnss-sdr: /build/gnuradio-BBYmSv/gnuradio-3.7.11/gnuradio-runtime/include/gnuradio/buffer.h:179: unsigned int gr::buffer::index_add(unsigned int, unsigned int): Assertion `s < d_bufsize' failed. Aborted (core dumped) Brian F. Thomson, Ph.D. Assistant Professor Director of Undergraduate Studies Senior Design Coordinator Electrical & Computer Engineering Temple University brian.thom...@temple.edu (215) 204 - 8737
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