A bit of advertising

August 22, 2014  •  Leave comment (1)

This year a book “GPS, GLONASS, Galileo, and BeiDou for Mobile Devices: From Instant to Precise Positioning” by author Dr Ivan G. Petrovski was published. It contains link of my article. More details about book are available through the link

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GLONASS: step towards CDMA

August 22, 2014  •  Leave comment (0)

This summer almost unnoticed event has happened. In june GLONASS-M (¹755) satellite with L3-band equipment was launched. Since beginning of august this satellite was included in GLONASS constellation. This means that at this moment there are two satellites capable of transmitting CDMA signals in L3 band...

BeiDou-2 (COMPASS) preliminary results

January 28, 2013  •  Leave comment (3)

On 27th of december 2012 China published full version of interface control document (ICD) for their GNSS system BeiDou-2 (COMPASS). This step opened way to building receivers that are capable of working with this GNSS.

Accuracy of FPGA receiver

July 03, 2012  •  Leave comment (1)

On the figure below coordinates variations are plotted. They are taken from FPGA+ARM receiver. The measurements were made during aproximately 1 hour with the speed of 1 measurement per second.

PVT_FPGA_variance.PNG

Variation of coordinates across each axis is about ±80 meters that approximately corresponds to software GPS receiver SoftGNSS.

FPGA + ARM = new results with hardware receiver

July 02, 2012  •  Leave comment (1)

On the figure below result of hardware receiver (FPGA+ARM-based) work is shown. The same demoboard as in the note From software receiver to hardware receiver or what can be achieved from a bundle of OSGPS and NAMURU was used. Now the software part of the project is running under real time operating system TNKernel. The project is based on correlator Namuru and software gpl-gps/namuru-gpl.

PVT_FPGA.png

For the moment the program works not stable. Sometimes incorrect synchronization for some channels happens and hence pseudoranges are calculated incorrectly. As a result wrong coordinates are calculated.

Improving the precision of the software receiver GLONASS L1

March 23, 2012  •  Leave comment (0)

Some time ago I became interested in improving the precision of GLONASS Scilab receiver. The difference between mean value and max/min values of coordinates up to ±35 m for stationary receiver – is too big.

PVT solution of GLONASS L1 Scilab receiver
Figure 1 PVT solution of GLONASS L1 Scilab receiver

After improving several weak parts of the code the difference between mean value and max/min values of coordinates lowered to ±6 m, i.e. almost in 6 times. Results from the updated version of the receiver is on the figure 1. The same signal record as in the post GLONASS - frist experiments was used.

Successful usage cases of published projects

March 21, 2012  •  Leave comment (0)

Not long time ago I have noticed master's thesis in which materials from my blog are used :) Here is the link: https://dspace.ist.utl.pt/...

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GLONASS L2: NEW RESULTS

February 07, 2012  •  Leave comment (0)

After a pause in developing GLONASS L2 software receiver for SciLab I found some time to work with it. The error that didn't allow to calculate correct PVT is fixed now. So GLONASS L2 scilab receiver is fully working now. PVT solution for L2 signals recorded in the may 2011 is shown on the figure 1.

PVT Solution based on GLONASS L2 signals.
Figure 1 PVT solution for L2.

Source code for acquisition and tracking algorithms of GLONASS L3 signals

October 09, 2011  •  Leave comment (1)

Acquisition and tracking source code is available for download now. It's a reworked version of GLONASS L1 software receiver for scilab.

All source code is moving to Google Code

September 24, 2011  •  Leave comment (3)

All source code is moving to Google Code now.

Current project list includes:
1) GNSS-SDR front-end project wich include:
    a) PCB designed in KiCAD;
    b) CPLD-project made in Xilinx ISE WebPack;
    c) Firmware for USB-bridge cy7c68013a;
2) Real-time GPS receiver GPS-SDR addition to work with gnss-sdr front-end;
3) None real-time GLONASS receiver for SCILAB;
4) Console MS Windows program for streaming data to HDD from gnss-sdr front-end;
5) Hardware project wich include:
    a) Namuru based correlator ported to work with Wishbone bus;
    b) OSGPS based single channel GPS receiver (example of how acquisition and tracking is made in hardware receiver). This projects works in conjuction with Namuru based correlator;