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GPS

GPS

Note

You need a GPS antenna for it to work

  • GPS frequency is 1.575420 GHz

GPS Frequencies

GNSS SDR

This is to receive the GPS signals and compute the corresponding location.
Source

Configuration:

>>> cat limesdr_GPS_L1.conf

[GNSS-SDR]

;######### GLOBAL OPTIONS ##################
GNSS-SDR.internal_fs_sps=2000000

;######### SIGNAL_SOURCE CONFIG ############
SignalSource.implementation=Osmosdr_Signal_Source
SignalSource.item_type=gr_complex
SignalSource.sampling_frequency=2000000
SignalSource.freq=1575420000
SignalSource.gain=40
SignalSource.rf_gain=40
SignalSource.if_gain=40
SignalSource.AGC_enabled=false
SignalSource.samples=0
SignalSource.repeat=false
;# Next line enables the internal HackRF One bias (3.3 VDC)
;#SignalSource.osmosdr_args=hackrf,bias=1
;# Next line enables the LimeSDR
SignalSource.osmosdr_args=driver=lime,soapy=0
SignalSource.enable_throttle_control=false
SignalSource.dump=false
SignalSource.dump_filename=./signal_source.dat

;######### SIGNAL_CONDITIONER CONFIG ############
SignalConditioner.implementation=Signal_Conditioner

;######### DATA_TYPE_ADAPTER CONFIG ############
DataTypeAdapter.implementation=Pass_Through

;######### INPUT_FILTER CONFIG ############
InputFilter.implementation=Freq_Xlating_Fir_Filter
InputFilter.decimation_factor=1
InputFilter.input_item_type=gr_complex
InputFilter.output_item_type=gr_complex
InputFilter.taps_item_type=float
InputFilter.number_of_taps=5
InputFilter.number_of_bands=2
InputFilter.band1_begin=0.0
InputFilter.band1_end=0.85
InputFilter.band2_begin=0.9
InputFilter.band2_end=1.0
InputFilter.ampl1_begin=1.0
InputFilter.ampl1_end=1.0
InputFilter.ampl2_begin=0.0
InputFilter.ampl2_end=0.0
InputFilter.band1_error=1.0
InputFilter.band2_error=1.0
InputFilter.filter_type=bandpass
InputFilter.grid_density=16
InputFilter.dump=false
InputFilter.dump_filename=../data/input_filter.dat

;######### RESAMPLER CONFIG ############
Resampler.implementation=Pass_Through

;######### CHANNELS GLOBAL CONFIG ############
Channels_1C.count=8
Channels.in_acquisition=1

;######### ACQUISITION GLOBAL CONFIG ############
Acquisition_1C.implementation=GPS_L1_CA_PCPS_Acquisition
Acquisition_1C.item_type=gr_complex
Acquisition_1C.coherent_integration_time_ms=1
Acquisition_1C.pfa=0.01
Acquisition_1C.doppler_max=5000
Acquisition_1C.doppler_step=250
Acquisition_1C.max_dwells=1
Acquisition_1C.dump=false
Acquisition_1C.sampled_ms=2
Acquisition_1C.dump_filename=./acq_dump.dat

;######### TRACKING GLOBAL CONFIG ############
Tracking_1C.implementation=GPS_L1_CA_DLL_PLL_Tracking
Tracking_1C.item_type=gr_complex
Tracking_1C.extend_correlation_symbols=10
Tracking_1C.early_late_space_chips=0.5
Tracking_1C.early_late_space_narrow_chips=0.15
Tracking_1C.pll_bw_hz=40
Tracking_1C.dll_bw_hz=2.0
Tracking_1C.pll_bw_narrow_hz=5.0
Tracking_1C.dll_bw_narrow_hz=1.50
Tracking_1C.fll_bw_hz=10
Tracking_1C.enable_fll_pull_in=true
Tracking_1C.enable_fll_steady_state=false
Tracking_1C.dump=false
Tracking_1C.dump_filename=tracking_ch_

;######### TELEMETRY DECODER GPS CONFIG ############
TelemetryDecoder_1C.implementation=GPS_L1_CA_Telemetry_Decoder
TelemetryDecoder_1C.dump=false

;######### OBSERVABLES CONFIG ############
Observables.implementation=Hybrid_Observables
Observables.dump=false
Observables.dump_filename=./observables.dat

;######### PVT CONFIG ############
PVT.implementation=RTKLIB_PVT
PVT.positioning_mode=Single
PVT.output_rate_ms=100
PVT.display_rate_ms=500
PVT.iono_model=Broadcast
PVT.trop_model=Saastamoinen
PVT.flag_rtcm_server=true
PVT.flag_rtcm_tty_port=false
PVT.rtcm_dump_devname=/dev/pts/1
PVT.rtcm_tcp_port=2101
PVT.rtcm_MT1019_rate_ms=5000
PVT.rtcm_MT1077_rate_ms=1000
PVT.rinex_version=2

Setting it up:

#Install stuff
yay gnss
yay mako

#Check LimeSDR
SoapySDRUtil --find
LimeUtil --find


#Run Profiling/Tests
volk_profile
volk_gnsssdr_profile

Running it:

sudo gnss-sdr --config_file=hackrf_GPS_L1.conf

LimeGPS

Real-time GPS signal simulator for LimeSDR

Transmit GPS

Source

Install the software:

sudo pacman -S base-devel hackrf gnuradio gnuradio-osmosdr

Make the software:

mkdir gps-spoof
cd gps-spoof
git clone https://github.com/osqzss/gps-sdr-sim.git
cd gps-sdr-sim
make

Download the current Satellite position information:
1. Download from https://cddis.nasa.gov/archive/gnss/data/daily/
2. Select current year and largest day number (current day).
3. Download the latest file starting with “brdc” into the gps-sdr-sim directory.
4. Unzip the file gunzip brdc<VARIES>n.gz

Generate and Transmit the Spoofing file:

#Generate the GPS File
./gps-sdr-sim -e brdc2260.21n -b 8 -l 36.16598363988784,-86.78167782570753,100
#Transmit the GPS File
limeplayer -s 1000000 -b 1 -d 2047 -g 0.1 < ../circle.1b.1M.bin