This page contains links for Software Defined Radios (SDRs) and Open GPS / GNSS receiver software.
After a talk by Mihai Dumitru from the Astronomical Society of Victoria on Radio Astronomy at The North East Radio Group's February 2007 meeting I was prompted to look at the GNU Radio "USRP" that Mihai would like to use for his radio telescope. Being interested in both FPGA design and amateur radio, I thought this would be a great way to combine both interests.
Matt Ettus designed the "USRP" Universal Software Radio Peripheral, that is referred to on the GNU Radio web site, which is based around an Altera FPGA. My FPGA expertise is based on Xilinx FPGAs rather than Altera devices, so I was hoping I could duplicate some of the work using a Memec / Avnet Xilinx Virtex 4 FX12 LC board with a P160 Analog module that includes two 12 bit 53 Msps ADCs and two 12 bit 165 Msps DACs. The Vitex 4 FX12 is not as large as the Altera device but includes a hard core PPC405 processor. The Power PC is capable of running Monta Vista Linux, with Xilinx EDK 7.1 Embedded Development Kit so I was hoping to use that as the basis of a receiver design.
Having worked in the past on GPS systems, I also thought that the "USRP", or a derivative of it, would also make a good GPS receiver. In addition to the high speed P160 Analog module, I would also need a GPS front end such as the Maxim MAX2745 which is available in evaluation kit form from Arrow Electronics (MAX2745-EVKIT) although the price of the kit is rather prohibitive for hobby use.
There is an open source GPS receiver design based on the Superstar II GPS receiver which uses an ARM7 CPU and Zarlink GPS receiver front end and correlator.
Another point of interest is that the "USRP" is supposed to be able to implement HDTV, although articles I have found on the internet suggest this is not yet a reality. Polari Zone produce a FPGA Software Defined Radio based around the Spartan 3.
Astronomy
Mihai Dumitru's Radio Astronomy Antennas (NASA Radio Jove newsletter June 2006)
http://radiojove.gsfc.nasa.gov/library/newsletters/2006Jun/
Software Defined Radio
GNU Software Radio Project
http://www.gnu.org/software/gnuradio/
GNU Radio on Wikipedia
http://en.wikipedia.org/wiki/GNU_Radio
Eric Blossom explains Software Radio
http://comsec.com/software-radio.html
Eric Blossom's GNU Radio Wiki Page
http://www.comsec.com/wiki?GnuRadioFaq
Software Defined Radio Forum
Software Defined Radio on Wikipedia.
http://en.wikipedia.org/wiki/Software_radio
Open Source High Performance Software Defined Radio
Phil Covington's Open Source Software Defined Radio
http://www.philcovington.com/SDR.html
Matt Ettus USB "Universal Software Radio Peripheral" using an Altera FPGA.
Flex-Radio Systems SDR-1000
Polari Zone Software Defined Radio (Spartan 3)
http://www.polarizone.com/products_sdr.htm
KD7LMO GNU Radio Web site
http://www.kd7lmo.net/ground_gnuradio.html
OSSIE - Open Source SDR SCA Implementation - Virginia Tech.
A LowFER Receiver Using a "Software" IF
http://www.qsl.net/k0lr/SW-RX/sw-rx.htm
DL4YHF's Spectrum Lab Audio Spectrum Analyzer
http://www.qsl.net/dl4yhf/spectra1.html
I2PHD's SDRadio - A Software Defined Radio
http://www.sdradio.eu/sdradio/
AmQRP SoftRock-40 Software Defined Radio Kit for 40m
http://www.amqrp.org/kits/softrock40/index.html
FlexRadio Systems - Software Defined Radios
Global Positioning System
Eric Blossom's GNU Radio GPS Wiki page
http://www.comsec.com/wiki?GlobalPositioningSystem
Krzysztof Kamieniecki's kkGPS site based on the USRP hardware
http://www.kamieniecki.com/krys/gps
University of New South Wales Satellite Navigation And Positioning Lab (SNAP).
http://www.gmat.unsw.edu.au/snap/
Open GPS at the University of Colorado
http://aes.colorado.edu/opengps/
GPL-GPS Home Page
http://gps.psas.pdx.edu/WebHome
Open Source GNSS Project
http://gps.psas.pdx.edu/OpenGnssProjects
Open Source GPS - C.W.Kelley
http://home.earthlink.net/~cwkelley/
GNSSTk - The Essential GNSS Project
http://gnsstk.sourceforge.net/
GPSTk - GPS Library - ARL University of Texas at Austin
http://www.gpstk.org/bin/view/Documentation/WebHome
Maxim MAX2745 GPS Receiver Front End Down Converter
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4325
Maxim MAX2745-EVKIT GPS RF Front End Evaluation Kit
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4564
Sparkfun Electronics SiGe GN3S Sampler V2
(Co developed by the GNSS Lab at the University of Colorado and SiGe)
http://www.sparkfun.com/commerce/product_info.php?products_id=8238
Book: A Software-Defined GPS and Galileo Receiver: A Single-Frequency Approach
http://www.amazon.com/Software-Defined-GPS-Galileo-Receiver-Single-Frequency/dp/0817643907
Field Programmable Gate Arrays
University of New South Wales Satellite Navigation And Positioning FPGA receiver research.
http://www.gmat.unsw.edu.au/snap/work/fpga_research.htm
Memec / Avnet Virtex 4 FX12 LC board
http://www.em.avnet.com/evk/home/...
Memec / Avnet P160 Analog Module
http://www.em.avnet.com/evk/home/...
Xilinx