GNSS software defined receiver

Updated on Dec 16, 2024

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A software GNSS receiver is a GNSS receiver that has been designed and implemented following the philosophy of Software-defined radio.

A GNSS receiver, in general, is an electronic device that receives and digitally processes the signals from a GNSS satellite constellation in order to provide position, velocity and time (of the receiver).

GNSS receivers have been traditionally implemented in hardware: a hardware GNSS receiver is conceived as a dedicated chip that have been designed and built (from the very beginning) with the only purpose of being a GNSS receiver.

In a software GNSS receiver, all digital processing is performed by a general purpose microprocessor. In this approach, a small amount of inexpensive hardware is still needed, known as the frontend, that digitizes the signal from the satellites. The microprocessor can then work on this raw digital stream to implement the GNSS functionality.

Hardware vs. software GNSS receivers

When comparing hardware vs software GNSS receivers, a number of pros and cons can be found for each approach:

Hardware GNSS receivers are in general more efficient from the point of view of both computational load and power consumption since they have been designed in a highly specialized way with the only purpose of implementing the GNSS processing.

Software GNSS receivers allow a huge flexibility: many features of the receiver can be modified just through software. This provides the receiver with adaptive capabilities, depending on the user's needs and working conditions. In addition, the receiver can be easily upgraded via software.

Under some assumptions, Software GNSS receivers can be more profitable for some applications, as long as sufficient computational power is available (and can be shared among multiple applications). For example, the microprocessor of a smartphone can be used to provide GNSS navigation with the only need of including a frontend (instead of a full, more expensive, hardware receiver).

Currently, most of the GNSS receiver market is still hardware. However, there already exist operational solutions based on the software approach able to run on low-cost microprocessors. Software GNSS receivers are expected to increase their market share or even take over in the near future, following the development of the computational capabilities of the microprocessors (Moore's law).

Comparison of implementations

This comparison is strictly about GNSS SDR; please do not include general GNSS positioning and mapping software.

Galileo Satellite Navigation LTD.- GSN:

URL: http://galileo-nav.com

Business Model - IP core license + royalties

Development

Programming language: C

User interface - NMEA

Hardware support:

Platforms

PC - windows

PC - Linux

CEVA - XC family

CEVA - TL3/4

Cadence (Tensilica) - BBE16/32

RF FE

MAXIM

NEC

GNSS/SBAS signals support:

GPS: L1/CA,

GLONASS: G1

Galileo: E1,

BeiDou: B1

SBAS

QZSS: L1/CA

Features:

Acquisition: yes

Tracking: yes

Generating pseudo-range observable: yes

Decoding navigation data: yes

Position estimation: yes

Maximum number of real-time channels demonstrated: 16/system

Multi-correlator: yes

Sample data recording: yes

SX3 (formerly SX-NSR)

General information:

URL: http://www.ifen.com/products/sx-scientific-gnss-solutions/sx-software-receiver.html

Publication: http://gpsworld.com/software-gnss-receiver-an-answer-for-precise-positioning-research

Development:

Programming language: C++

User interface (none, CLI, GUI): CLI, GUI

Under active development (as-of date): yes (2016-Mar-17)

Creator/sponsor organization: IfEN GmbH, Germany

Latest release (version and date): v3.2.1, March 2016

First release (version and date): v1.0, March 2007

Hardware support:

Front-ends: NavPort, NavPort-4, SX3 frontend

Host computer special hardware supported: SIMD (SSE2, SSSE3), CUDA

Multicore supported: yes

GNSS/SBAS signals support:

GPS: L1CA, L2C, L2P (codeless), L5

GLONASS: G1, G2

Galileo: E1, E5a, E5b, E5ab (AltBOC), E6

BeiDou: B1, B2

SBAS: EGNOS

QZSS: L1CA

IRNSS: L5, S-Band

Features:

Acquisition: yes (several algorithms)

Tracking: yes (several algorithms)

Generating pseudo-range observable: yes

Generating carrier-phase observable: yes

Decoding navigation data: yes

Spectrum analyzer: yes

Position estimation: yes

Maximum number of real-time channels demonstrated: 490 (GPS L1 C/A channels @20 MHz sample rate, 3 correlators per channel, INTEL Core i7-4970K processor (not over clocked) )

Application programming interface: yes

Dual antenna support: yes

Scintillation monitoring: yes

Multi-correlator: yes

Sample data recording: yes

Multipath mitigation: yes (several algorithms)

GNSS-SDRLIB

General information:

URL: http://www.taroz.net/gnsssdrlib_e.html

Publication:

Software licence:

Development:

Programming language: C

User interface (none, CLI, GUI): CLI, GUI.

Number of developers: 1?

Under active development (as-of date): yes (2013-Sep-25)

Creator/sponsor organization: Tokyo University of Marine Science and Technology, Japan

Latest release (version and date):

First release (version and date):

Hardware support:

Front-ends: NSL STEREO v2 and SiGe GN3S Sampler v3

Host computer special hardware supported: SIMD (SSE2 and AVX)

Multicore supported?:

GNSS/SBAS signals support:

GPS: L1CA, L1C, L2C, L5

GLONASS: G1, G2

Galileo: E1, E5a, E5b

BeiDou: B1

QZSS: LEX

Features:

Acquisition: yes

Tracking: yes

Generating pseudo-range: yes

Decoding navigation data: yes

Spectrum analysis: yes

Position estimation: yes (through RTKLIB)

Maximum number of real-time channels demonstrated: ?

ARAMIS(TM) (formerly iPRx)

Versions:

Free academic version : http://www.ip-solutions.jp/free%20SDR%20receiver.html

Ionospheric Scintillation Monitor receiver

R&D version

General information:

URL: http://www.ip-solutions.jp/ionosphere_scintillation_monitor.html

Publication: http://www.cambridge.org/us/academic/subjects/engineering/communications-and-signal-processing/digital-satellite-navigation-and-geophysics-practical-guide-gnss-signal-simulator-and-receiver-laboratory

Development:

Programming language: C++

User interface : GUI

Under active development (as-of date): yes (2014-Nov)

Creator/sponsor organization: iP-Solutions, Japan, JAXA, Japan

Latest release (version and date): April 2014

First release (version and date): April 2008

Hardware support:

Front-ends: Eagle, FEM, MFR

Multicore supported: yes

GNSS/SBAS signals support:

GPS: L1CA, L2P (codeless)

GLONASS: G1, G2

Galileo: E1

QZSS: L1CA

Features:

Acquisition: yes

Tracking: yes

Generating pseudo-range observable: yes

Generating carrier-phase observable: yes

Decoding navigation data: yes

Position estimation: yes

Maximum number of real-time channels : 60 (5 correlators per channel)

Application programming interface: yes

Dual antenna support: yes, for FEM front end

Multi-correlator: yes

Sample data recording: yes

SoftGNSS v3.0 (also known as SoftGPS)

General information:

URL: SoftGNSS @ Aalborg Team , SoftGNSS @ University of Colorado

Publication: http://www.springer.com/birkhauser/engineering/book/978-0-8176-4390-4

Source code: included with the book

Software licence: GPL v2

Non real-time (post-processing) GNSS software receiver

Development:

Programming language: MATLAB

User interface (none, CLI, GUI): CLI and GUI

Number of developers: 4 (along the project)

Under active development (as-of date): public version - no, non-public versions - yes (2013-Sep-30)

Hardware support:

Front-ends: SiGe GN3S Sampler v1 (in the original SDR and driver release). Signal records originating from other Sampler versions or other front-ends require configuration changes and in some cases also minor code changes.

Host computer special hardware supported: no

Multicore supported?: no

GNSS/SBAS signals support (separate version for each band of each GNSS):

GPS: L1CA

Features:

Acquisition: yes

Tracking: yes

Generating pseudo-range observable: yes

Generating carrier-phase observable: no

Decoding navigation data: yes

Position estimation: yes

GNSS-SDR, An open source GNSS Software Defined Receiver

General information:

URL: http://gnss-sdr.org/

Source code:

https://github.com/gnss-sdr/gnss-sdr.git

Software licence: GPL v3

Development:

Programming language: C++

User interface (none, CLI, GUI): CLI.

Number of developers: 8 (along the project)

Under active development (as-of date): yes (2016-Sep-24)

Creator/sponsor organization: Centre Tecnològic de Telecomunicacions de Catalunya

Latest release (version and date): 0.0.8 (as Sept. 2016)

First release (version and date): 2011-Mar-11 first svn commit

Hardware support:

Front-ends: UHD-compatible (USRP v1, v2, etc.), OsmoSDR, RTL2832-based USB dongles and SiGe GN3S Sampler v2

Host computer special hardware supported: SIMD (via VOLK and VOLK_GNSSSDR), CUDA

Multicore supported?: Yes

GNSS/SBAS signals support:

GPS: L1CA

GLONASS:

Galileo: E1b, E1c

BeiDou:

SBAS: EGNOS

Features:

Acquisition: yes (several algorithms)

Tracking: yes (several algorithms)

Generating pseudo-range observable: yes

Generating carrier-phase observable: yes

Decoding navigation data: yes

Position estimation: yes

Maximum number of real-time channels demonstrated: > 100

Output formats: RINEX, KML, RTCM

GNSS-SDR, An open source GNSS Software Defined Receiver based on SoftGNSS v3.0

General information:

URL: http://gnss-sdr.ru/index.php?blogid=2

Source code: https://code.google.com/p/gnsssdr/

Software licence: GPL v3

Non real-time (postprocessing) GNSS software receiver

Development:

Programming language: SciLab

Number of developers: 1

Under active development (as-of date): yes (2013-Sep-25)

GNSS/SBAS signals support (separate version for each band of each GNSS):

GPS: L1CA

GLONASS: L1SP, L2SP, L3 (L3 CDMA is under development)

Galileo: E1 (under development)

BeiDou: B1I

Features:

Acquisition: yes

Tracking: yes

Generating pseudo-range observable: yes

Generating carrier-phase observable: no

Decoding navigation data: yes

Position estimation: yes

TRIGR

OpenSourceGPS

NAMURU

GNSS SDR Tools for Education and Research

GPL-GPS

GPSRCVR

WitchNavigator

kkGPS

ipexSR

GSNRx

SNACS snSDRGPS

SoftGNSS

iPRx

GMV srx-10

FGI-GSRx

Front-ends

Ettus USRP ($675+)

Nuand bladeRF ($420+)

CCAR/SiGe/sparkfun GN3S ($450,$405)

Digial TV Dongle ($25?)

NSL STEREO v2 (£650)

gnss-sdr.ru open-hardware L1 band

OneTalent GNSS SdrNavXX (€250-800)

iP-Solutions academic (Eagle), multi-system (FEM), multi-frequency (MFR) GNSS front ends (from $550)

TeleOrbit GTEC RFFE developed by Fraunhofer IIS

References

GNSS software-defined receiver Wikipedia

(Text) CC BY-SA

Contents

Hardware vs. software GNSS receivers

Comparison of implementations

Front-ends

References