Pocket SDR is an open-source GNSS (Global Navigation Satellite System) receiver based on the SDR (software defined radio) technology. It consists of an RF front- end device, some utilities for the device, and GNSS-SDR APs (application programs) written in Python and C. It supports almost all signals for GPS, GLONASS, Galileo, QZSS, BeiDou, NavIC, and SBAS.
The RF front-end device consists of 2 CH Maxim MAX2771 GNSS RF front-end ICs (LNA, mixer, filter, ADC, frequency synthesizer) and a Cypress EZ-USB FX2LP USB 2.0 controller to connect to host PCs. The front-end CH1 is dedicated for GNSS L1 band (1525 - 1610 MHz), and CH2 is for GNSS L2/L5/L6 band (1160 - 1290 MHz). The frequency of the reference oscillator (TCXO) is 24.000 MHz, and the ADC sampling frequency can be configured up to 32 MHz.
Pocket SDR contains some utility programs for the RF front-end device to configure the device, capture and dump the digitized IF (inter-frequency) data. These utilities support Windows, Linux, and other environments.
Pocket SDR also provides GNSS-SDR APs to show the PSD (power spectrum density) of captured IF data, search the GNSS signals, track these signals, and decode navigation data in them. The supported GNSS signals are as follows. For details on these signals and signal IDs used in the Pocket SDR APs, refer Pocket SDR Signal IDs.
- GPS: L1C/A, L1C-D, L1C-P, L2C-M, L5-I, L5-Q
- GLONASS: L1C/A (L1OF), L2C/A (L2OF), L1OCd, L1OCp, L2OCp, L3OCd, L3OCp
- Galileo: E1-B, E1-C, E5a-I, E5a-Q, E5b-I, E5b-Q, E6-B, E6-C
- QZSS: L1C/A, L1C/B, L1C-D, L1C-P, L1S, L2C-M, L5-I, L5-Q, L5S-I, L5S-Q, L6D, L6E
- BeiDou: B1I, B1C-D, B1C-P, B2a-D, B2a-P, B2I, B2b-I, B3I
- NavIC: L1-SPS-D, L1-SPS-P, L5-SPS
- SBAS: L1C/A, L5-I, L5-Q
These APs are written in Python and C by very compact way. They are easily modified by users to add user's unique algorithms.
The introduction of Pocket SDR is shown in the following slides.
T.Takasu, An Open Source GNSS SDR: Development and Application, IPNTJ Next GNSS Technology WG, Feb 21, 2022 (https://gpspp.sakura.ne.jp/paper2005/IPNTJ_NEXTWG_202202.pdf)
For an application of Pocket SDR, refer the following slides.
T.Takasu, Development of QZSS L6 Receiver without Pilot Signal by using SDR, IPNTJ Annual Conference, June 10, 2022 (https://gpspp.sakura.ne.jp/paper2005/IPNTJ_20220610.pdf)
PocketSDR --+-- bin Pocket SDR utilities and APs binary programs for Windows
+-- app Pocket SDR utilities and APs source programs
+-- src Pocket SDR library source programs
+-- python Pocket SDR Python scripts
+-- lib External library for utilities and APs
+-- conf Configuration files for device settings
+-- driver Windows driver for EZ-USB FX2LP/FX3 (cyusb3.sys) ([4])
+-- doc Documents (ref [1], [2])
+-- FW Firmware source programs and images
| +-- cypress Cypress libraries for EZ-USB firmware development
| (ref [4])
+-- HW Pocket SDR RF frontend CAD data and parts list
| (*.brd and *.sch are for Eagle, *.f3d is for Fusion 360)
+-- image Image files for documents
+-- sample Sample digital IF data captured by Pocket SDR
+-- test Test codes
- Extract PocketSDR.zip to an appropriate directory <install_dir>.
- Attach Pocket SDR RF frontend to PC via USB cable.
- Install USB driver (CYUSB) for Pocket SDR RF frontend according to PocketSDR\driver\readme.txt.
- Add the Pocket SDR binary programs path (<install_dir>\PocketSDR\bin) to the command search path (Path) of Windows environment variables.
- Add the Pocket SDR Python scripts path (<install_dir>\PocketSDR\python) to the command search path (Path) of Windows environment variables.
- To rebuild the binary programs, you need MinGW64. Refer MSYS2 (https://www.msys2.org/) for details.
- In MinGW64 environment, you need fftw3 library. To install fftw3 library.
$ pacman -S mingw-w64-x86_64-fftw
- Extract PocketSDR.zip or clone the Git repository to an appropriate directory <install_dir>.
$ unzip PocketSDR.zip
or
$ git clone https://github.com/tomojitakasu/PocketSDR
- Install libusb-1.0 developtment package. For Ubuntu:
$ sudo apt install libusb-1.0-0-dev
- Install libfftw3 developtment package. For Ubuntu:
$ sudo apt install libfftw3-dev
- Move to the library directory, install external library source trees ([5], [6], [7]) as follows:
$ cd <install_dir>/lib
$ git clone https://github.com/quiet/libfec
$ git clone https://github.com/radfordneal/LDPC-codes
$ git clone https://github.com/tomojitakasu/RTKLIB -b rtklib_2.4.3
- Move to the library build directory, build libraries.
$ cd <install_dir>/lib/build
$ make
$ make install
- Move to the application program directory, build utilities and APs.
$ cd <install_dir>/app
$ make
$ make install
- Add the Pocket SDR binary programs path (<install_dir>/PocketSDR/bin) to the command search path.
- Usually you need to have a root permission to access USB devices. So you have to add "sudo" to execute pocket_conf, pocket_dump like:
$ sudo pocket_conf ../conf/pocket_L1L6_12MHz.conf
$ sudo pocket_dump -t 10 ch1.bin ch2.bin
- Add the Pocket SDR Python scripts path (<install_dir>/PocketSDR/python) to the command search path (Path) and set permissions.
$ cd <install_dir>/python
$ chmod +x *.py
Pocket SDR contains the following utility programs.
- pocket_conf: SDR device configurator
- pocket_scan: Scan and list USB Devices
- pocket_dump: Capture and dump digital IF data of SDR device
For details, refer comment lines in src/pocket_conf.c, src/pocket_scan.c, src/pocket_dump.c.
Pocket SDR contains the following application programs for GNSS-SDR.
- pocket_psd.py : Plot PSD and histograms of digital IF data
- pocket_acq.py : GNSS signal acquisition in digital IF data
- pocket_trk.py : GNSS signal tracking and navigation data decoding in digital IF data
- pocket_snap.py: Snapshot positioning with digital IF data
- pocket_plot.py: Plot GNSS signal tracking log by pocket_trk.py
- pocket_acq : C-version of pocket_acq.py (w/o graph plots)
- pocket_trk : C-version of pocket_trk.py (w/o graph plots)
- pocket_snap : C-version of pocket_snap.py
For details, refer comment lines in python/pocket_psd.py, python/pocket_acq.py, python/pocket_trk.py, python/pocket_snap.py and python/pocket_plot.py. You need Python 3, Numpy, Scipy and matplotlib to execute Python scripts.
$ sudo pocket_conf
...
$ sudo pocket_conf conf/pocket_L1L6_12MHz.conf
Pocket SDR device settings are changed.
$ sudo pocket_dump -t 5 ch1.bin ch2.bin
TIME(s) T CH1(Bytes) T CH2(Bytes) RATE(Ks/s)
5.0 I 60047360 IQ 120094720 11985.5
$ pocket_psd.py ch1.bin -f 12 -h
$ pocket_acq.py ch1.bin -f 12 -fi 3 -sig L1CA -prn 1-32,193-199
SIG= L1CA, PRN= 1, COFF= 0.23492 ms, DOP= -1519 Hz, C/N0= 33.6 dB-Hz
SIG= L1CA, PRN= 2, COFF= 0.98558 ms, DOP= 2528 Hz, C/N0= 33.8 dB-Hz
SIG= L1CA, PRN= 3, COFF= 0.96792 ms, DOP= 3901 Hz, C/N0= 33.7 dB-Hz
SIG= L1CA, PRN= 4, COFF= 0.96192 ms, DOP= -1957 Hz, C/N0= 40.4 dB-Hz
...
$ pocket_acq.py ch1.bin -f 12 -fi 3 -sig L1CA -prn 4
$ pocket_acq.py ch1.bin -f 12 -fi 3 -sig L1CA -prn 8 -3d
$ pocket_acq.py ch2.bin -f 12 -sig L6D -prn 194 -p
$ pocket_trk.py ch1.bin -f 12 -fi 3 -sig L1CA -prn 1-32
TIME(s): 5.00 SRCH: 0 LOCK: 8/ 32
CH SIG PRN STATE LOCK(s) C/N0 (dB-Hz) COFF(ms) DOP(Hz) ADR(cyc) SYNC #NAV #ERR #LOL NER
4 L1CA 4 LOCK 4.99 41.7 ||||||| 0.9680586 -1947.0 -9713.3 -B-- 0 0 0 0
7 L1CA 7 LOCK 4.99 35.1 ||| 0.4019474 3676.0 18351.1 -B-- 0 0 0 0
8 L1CA 8 LOCK 4.99 46.5 |||||||||| 0.4476165 2532.0 12638.9 -B-- 0 0 0 0
9 L1CA 9 LOCK 4.99 37.6 ||||| 0.9303968 -376.9 -1867.8 -B-- 0 0 0 0
16 L1CA 16 LOCK 4.99 46.6 ||||||||||| 0.9330322 -418.9 -2089.4 -B-- 0 0 0 0
18 L1CA 18 LOCK 4.99 42.4 |||||||| 0.7254252 -1763.4 -8791.6 -B-- 0 0 0 0
26 L1CA 26 LOCK 4.99 45.8 |||||||||| 0.7427075 -1445.7 -7211.6 -B-- 0 0 0 0
31 L1CA 31 LOCK 4.99 45.0 |||||||||| 0.7491922 -3013.1 -15036.7 -B-- 0 0 0 0
...
$ pocket_trk.py ch1.bin -f 12 -fi 3 -sig E1B -prn 18 -p
...
$ pocket_trk.py ch2.bin -f 12 -sig E6B -prn 4 -log trk.log -p -ts 0.2
...
With pocket_dump and pocket_trk, you can track GNSS signals in real-time. By using -r option in pocket_dump and pocket_trk, the captured 2 CH IF data can be handled as raw data format. In addition, multiple signal tracking feature is added to pocket_trk (C-version of pocket_trk.py) in ver. 0.9.
For example, to track L1C/A and L5I signals of GPS in real-time, the following commands can be used. In this case, the tracking log is output as a TCP server with the port number 5070. For detailed options, please refer the comment lines in the source codes of app/pocket_dump/pocket_dump.c or app/pocket_trk/pocket_trk.c. For other samples, please refer test/pocket_trk_*_test.sh.
$ sudo pocket_dump -r -q - -c conf/pocket_L1L5_24MHz.conf | \
pocket_trk -r -f 24 -fi 6,0 -sig L1CA -prn 1-32 -sig L5I -prn 1-32 \
-log :5070
- Install Cypress EZ-USB FX2LP Development Kit (ref [4]) to a Windows PC. As default, it is installed to C:\Cypress and C:\Keil.
- Execute Keil uVision2 (C:\Keil\UV2\uv2.exe).
- Execute Menu Project - Open Project, select <install_dir>\PocketSDR\FW\pocket_fw.Uv2> and open the project.
- Execute Menu Project - Rebuild all target files and you can get a F/W image as <install_dir>\PocketSDR\FW\pocket_fw.iic.
- Attach Pocket SDR RF frontend via USB cable to the PC.
- Execute USB Control Center (C:\Cypress\USB\CY3684_EZ-USB_FX2LP_DVK\1.1\Windows Applications
c_sharp\controlcenter\bin\Release\CyControl.exe). - Select Cypress FX2LP Sample Device, execute menu Program - FX2 - 64KB EEPROM, select the F/W image <install_dir>\PocketSDR\FW\pocket_fw.iic and open it.
- If you see "Programming succeeded." in status bar, the F/W is properly written to PocketSDR.
[1] Maxim integrated, MAX2771 Multiband Universal GNSS Receiver, July 2018
[2] Cypress, EZ-USB FX2LP USB Microcontroller High-Speed USB Peripheral Controller, Rev. AB, December 6, 2018
[3] (deleted)
[4] Cypress, CY3684 EZ-USB FX2LP Development Kit (https://www.cypress.com/documentation/development-kitsboards/cy3684-ez-usb-fx2lp-development-kit)
[5] https://github.com/quiet/libfec
[6] https://github.com/radfordneal/LDPC-codes
[7] https://github.com/tomojitakasu/RTKLIB
- 2021-10-20 0.1 1st draft version
- 2021-10-25 0.2 Add Rebuild F/W and Write F/W Image to PocketSDR
- 2021-12-01 0.3 Add and modify Python scripts
- 2021-12-25 0.4 Add and modify Python scripts
- 2022-01-05 0.5 Fix several problems.
- 2022-01-13 0.6 Add and modify Python scripts
- 2022-02-15 0.7 Improve performance, Add some Python scripts.
- 2022-07-08 0.8 Add C-version of pocket_acq.py and pocket_trk.py.
- 2024-01-03 0.9 Add C-version of pocket_snap.py. pocket_trk supports multi-signal and multi-threading
- 2024-01-12 0.10 Support NavIC L1-SPS-D, L1-SPS-P, GLONASS L1OCd, L1OCp and L2OCp.
- 2024-01-25 0.11 Support decoding of GLONASS L1OCd NAV data Support NB-LDCP error correction for BDS B1C, B2a and B2b