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Weird results (PRN127 is really GAGAN?)

January 27, 2008, 7:31 am
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Nothing special,
just posting some strange acquisition results I've been achieving in Nottingham (UK). How can it be that GAGAN signal (PRN127) was stronger than EGNOS?

Figure 1: INMARSAT 4-F1 (PRN127) orbit data. Courtesy of heavens-above.com


Fig. 2: The code search space, definitely an acquisition...


Fig. 3: The SBAS PRNs correlation result hystogram. PRN127 is stronger than PRN120, PRN124, and PRN126?


Fig 4: As a comparison, the GPS PRNs correlation result hystogram...


Fig. 5: And finally, ESA's creature (should I say Surrey's creature maybe?) is still happily transmitting its data... Go Galileo, go!


P.S.: The front-end is this time a Rakon GRM6800 (nice piece of hw believe me).
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It says so...

February 19, 2008, 1:35 pm
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Today I convolutional decoded the messages sent by PRN127.
Then I used the SBAS teacher to interprete the result and, well, you can see the message 9 yourself.

Fig. 1: "SBAS teacher" (contribute of ESA) to interpret MSG9.

X: 18521754.08 Y: 37836816.64 Z:1649068.8
that is
Lat: 2.24398167 Lon: 63.9174794 Alt: 35781111.72

See the snapshot of the view of the earth from the satellite!

Fig. 2: How actually the PRN127 bird sees the earth.

If my calculations are not wrong, from Nottingham is
Elev: 7.959023 Azim: 108.99077 Distance: 40797572.51

I leave comments to the readers :)

P.S.: Thanks to Massimo and Simone for your precious contributes!
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GIOVE-B

May 12, 2008, 7:35 am
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How to acquire GIOVE-B?
- Take out your favorite GNSS data grabber from the drawer.
- Collect some signal when GIOVE-B is up in the sky (a simple patch antenna does the job).
- Perform a fine frequency search around the Doppler value estimated with the Norad orbital model (square the signal, you need more than 1 bit quantization).
- Set the code generation registers with the ones used by GIOVE-A.
- Initialize one register with all ones, and brute force crack the initialization value for the other one!
- Perform acquisition.

Result:
# G1 code generator
regOne = [1 0 0 1 1 0 1 0 1 1 0 0 0];
regOneInit = [1 1 1 1 1 1 1 1 1 1 1 1 1];
# G2 code generator
regTwo = [1 1 0 0 0 1 1 1 1 0 0 0 0];
regTwoInit = [1 0 0 1 1 1 1 1 1 1 1 0 0];

Fig 1: Normalised cross correlation
Fig 2: Normalised cross correlation (zoom around peak)

P.S.: Alternatively, you can go to http://waas.stanford.edu/GalileoCode/GIOVEB_L1.html
The people there have been, again, the first to officially crack the code. Congratulations!

P.P.S: If you are able to track it, you'll see it is still transmitting (mostly) dummy messages. These were received today at NSL (Nottingham Scientifc Ltd):
28e0491049115a20491000000010c0: 0000
290001355a200134c054000002f1c0: 0000
292000006500c912d8bc0000003a80: 0000
2940008cda1ffffff394000003bd00: 0000
2963fffe742c007ca5540000008900: 0000
298155555555555555540000037c40: 0000
29a15555555555555554000001a780: 0000
29c15555555555555554000000e000: 0000
29e155555555555555540000023bc0: 0000
2a0155555555555555540000022f40: 0000
2a215555555555555554000000f480: 0000
2a415555555555555554000001b300: 0000
2a61555555555555555400000368c0: 0000
2a8155555555555555540000033c00: 0000
2aa15555555555555554000001e7c0: 0000
2ac15555555555555554000000a040: 0000
2ae155555555555555540000027b80: 0000
2b01555555555555555400000009c0: 0000
2b215555555555555554000002d200: 0000
2b4000959c00915955540000015880: 0000
2b6000c48cc8d0cd1554000001e800: 0000
2b8000d59c00d15955540000008900: 0000
2ba15555555555555554000003c140: 0000
2bc1555555555555555400000286c0: 0000
2be020000124456880940000007900: 0000
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New signal samplers

September 25, 2008, 9:14 am
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Hello,
It's been a long time since I posted something... I have been busy with some hardware development.
But in my Company we finally have some new data grabber prototypes for our software receiver (and the future ones).

The first is a neat USB dongle:


The second is bigger (has more "stuff" inside of course):


Well I'm not allowed to say too much but.. these two have in common:
- the RF chip from Maxim-Dallas MAX2769,
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/5241
- a Rakon IT3205 TCXO with 1ppm accuracy,
http://www.rakon.com/models/display_model?model_id=503&reset=1&dont_refine=1&action=display
- a USB 2.0 micro controller.

The big one has inside also CPLD:
http://en.wikipedia.org/wiki/CPLD
This is inserted between the RF chip and the USB micro controller, and can perform simple data pre-processing before streaming the signal samples to the computer.

The beauty is that the micro controller firmware allows to program the RF chip and the CPLD in software, as many times as you want.

Like them?

Maybe more coming soon,
Michele
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Did I mention that...

January 19, 2009, 11:30 am
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Hello,
did I mention that with the CPLD version of the dongle we can receive Beidou-M1, the first satellite of the Chinese global navigation system?
The bird transmits a BPSK(2) on a 1561.098 MHz carrier. Slightly modifying the Matlab code from the book "A Software-Defined GPS and Galileo Receiver. A single frequency approach" by Kai Borre, Dennis M. Akos, Nicolaj Bertelsen, Peter Rinder, and Soren Holdt Jense, I got the following results:

We then decoded some subframes :)
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And soon I will publish some more results...

Michele
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An interesting signal modulation

February 1, 2009, 4:49 pm
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With GIOVE-B, the second satellite of the IOV Galileo constellation, a new modulation is being experimented, the CBOC(6,1,1/11).
With the CPLD version of NSL dongle and a bit of software, I did get the result below.. is not smooth and as beautiful as Septentrio's one (http://www.septentrio.com/news_news.htm), but it demonstrates some interesting capabilities already.

Fig.1: Tracking the CBOC(6,1,1/11) with a BOC(1,1) replica, a BOC(6,1) replica, and the sum of of the two.

In a couple of week I would like to show something else... let's see.

Michele
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Ticking the last box: Glonass L1

February 20, 2009, 2:50 pm
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Hello!
We had to wait long enough for some RF filters. Half a hour after receiving them, the Maxim MAX2769 which is fitted on our NSL USB dongle tuned correctly on Glonass frequency. I had to quickly make up a bit of Matlab code, and off I went acquiring Russian birds over Nottingham skies.
Result: 8 satellites. Pictures attached.

Fig. 1: The signal characteristics show some interference peak, and the gain should to be increased a bit.


Fig. 2: The typical histogram of acquired channels. This time is Glonass.


Some details of the channels:


Fig. 3: Details about the individual channels.


I hope the MAX2769 has no secrets any more :)


The next post will be something new, about a new exciting Software Defined Radio GNSS receiver!

Michele
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Still alive and working hard

December 3, 2009, 6:13 am
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Hi,

despite not writing anything in here, I have been working on a new version of the dongle and on many other things.

First, I'm now in hardware design: look at the new signal samplers, my personal joy and pride :)

Fig.1: Primo USB dongles: very flexible GNSS data samplers.

These have the same functionality of the old CPLD version, but are more slick and robust. Eheh!

Second, I'm playing with a new platform:

Fig.2: The Gumstix Overo Earth runs our software GNSS receiver.

Above is one of our dongles connected to a Gumstix OVERO earth carrier board. Not only the OMAP3503 can reliably record the raw GNSS stream, but it is also capable of processing 16 GPS -or Galileo BOC(1,1)- channels in real-time, continuously!
To do that, quite some assembly code had to be written (especially for the FFTs!). The NEON core within the Cortex-A8 is a wonderful machine, and the learning curve with gcc is very acceptable. I won't give more details of how we did it, just want to share -again- my joy and pride :)

To finish, this time I HAVE TO thank all my colleagues-friends working hard with me at NSL, and the opensource community of the Beagleboard and the BeagleSDR project.

Cheers!
Mic

P.S.: Next post is coming soooon...
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Opening the door to new signals

April 29, 2010, 8:22 am
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Well,

I don't manage to keep my promise of updating regularly this blog (blush). Anyway, I am improving little by little so another pretty stable thing is a board which I use to capture the new civil signals from GPS, Glonass, Galileo, Compass. I might refer to it as "TUNE".

Figure 1: Six single channel TUNE boards.

With a much wider bandwith than PRIMO, these boards can capture through USB a continuous endless stream of E5AltBOC signal with 1 bit quantisation (122.88Mbps). Two can also be connected together to have some sort of a dual-frequency sampler.

At the moment, the GUI to configure everything (tuner, clock distribution, ADC) is a little "complicated":

Figure 2: The TUNE configuration GUI.


...so it's my next part-time job to make it little more user friendly.
Some results of acquisitions and tracking of "famous" signals will follow shortly.


Regards everyone and thanks for all the comments had so far,
Michele
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Galileo E5AltBOC tracking in slow motion

May 12, 2010, 2:29 am
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Hello everyone,

not grabbed with our "TUNE" boards (the plot would not be as detailed at 61.44Msps) but with our next one I did not write about yet (samples at about 440Msps), here is a basic E5AltBOC pilot signal tracking:


Figure 1: Galileo PRN02 E5AltBOC tracking. Spirent GSS8000 simulator, static scenario, GPS L1, L2, L5, Galileo E1, E5a/b, E6 all in view.



Figure 1: GIOVE-B E5AltBOC tracking. Clear sky conditions, Novatel GPS704-X antenna, static scenario in Nottingham, May the 6th 2010, 00:05 GMT.


These animations are obtained using octave and ffmpeg... at 40x slower motion :)

More to come soon,
Michele
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Linking PRIMO with gps-sdr

May 13, 2010, 8:31 am
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Hello,

just finished adapting the open-source project www.gps-sdr.com to use PRIMO. On our Ubuntu Karmic 32bit laptop runs nicely but still uses a lot of resources (especially the GUI). The effect is nevertheless outstanding!

Figure 1: The gps-sdr GUI running with PRIMO (PVT window).

Figure 1: The gps-sdr GUI running with PRIMO (alm. and eph. window).


I really have to congratulate with Gregory Heckler and his colleagues for the fantastic job they have done so far. Every PRIMO user can now also enjoy their open-source receiver.

Thank you guys,
Michele


P.S. On their project website you should be able to find the archive with a preliminary snapshot of the code. Compile and run the GUI with ./gps-gse and the receiver with sudo ./gps-sdr -primo. I had no time to test it with the USRP 'cause we only have tweaked ones in the lab.. just be aware I tuned the scaling in acquisition and correlators.
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Snapshot post-processing with PRIMO

July 22, 2010, 6:22 am
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Hi,

Today I'd like to show what Ben, Luis, and me have been doing in our spare time and sometimes sacrifying our precious weekend hours.

Internal codename RETROFIX, it's a service running on one of our servers and processing small snapshots of data collected with PRIMO. At the moment uses about 200ms of signal and it's therefore limited in sensitivity. But surely it proofs the concept that with a coarse time tag and 128kBytes of digitized RF signal you can calculate the position and the time of a user.



If you have a PRIMO dongle just contact me and I'll send you the website address, the configuration files, and the application to grab a compatible signal: I'd love to have some feedback.

Come back soon for updates,
Mic
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Ladies and gentlemen, our "Wave"

October 23, 2010, 9:56 am
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Hi,


This is a special post for me, there is just so much work behind it that I feel literally relieved :)


Figure 1: Wave GNSS front-end.




Luis and me went through a quantity of problems, but eventually this week we can claim that Wave works reliably and performs well.
So here it is, our vision of an industrial direct bandpass sampling, multi-constellation, multi-frequency receiver.


Figure 2: Wave digital board rev1.1 with LVDS, USB, and GigETH connectors exposed.

Figure 3: Wave RF board rev1.1 with dual band filters and variable gain amplifiers

I will not explain the theory behind it, just post a file captured with a Novatel GPS-704X antenna at NSL. With your favourite acquisition algorithm, you may find in there all the currently available satellite navigation signals. And if you know what we are talking about, you know you just need one parameter: f_S = 5.4e8.

By the way, we will be done soon with porting gps-sdr. Wave has already passed the overnight stress test with it on a 64-bit Ubuntu distribution.


Figure 4: gps-sdr processing GPS L1 as digitised and conditioned by Wave. Take a look at the spectrum of the signal on the left (we have a strong external interference at 1.369 MHz, we don't know who's responsible YET). And of course Luis' empty tea mug on the right, filled with champagne later that afternoon :)


We hope readers will find this tool as intriguing as we do. We like to think that we made one step towards the ultimate real-time all-frequencies, all constellations software receiver. Any takers of our challenge?


To be continued,
Luis and Michele
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Open source Software Defined Radio GPS receiver

November 12, 2010, 8:48 am
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Hello,

Just a quick update to the people who are involved on gps-sdr.
Here is a version that (as far as I am aware) compiles on Ubuntu Lucid (32 and 64 bits).
And if you don't have any of NSL's GNSS data grabber, here is file captured with Primo which should give you a position in Nottingham :)

Cheers,
Michele


P.S. Please note that I am not a maintainer of gps-sdr, so please do not ask me for support on how to install the software or other trivial receiver stuff. Also, I don't take any responsibility for the modifications I have done. In practice, take the code you need from it.. and that's about it!
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A new adventure in GNSS

February 20, 2011, 12:53 pm
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Hi,

I am afraid nothing has happened on my GNSS blog for too long now, so I guess I should give some really big news this time ;)
Well, I would love to write about my latest GNSS creation... but I am not allowed :(
I hope this will not happen in the future... in fact, I am now working on a project called One Talent GNSS: a small business to provide GNSS consultancy and "gadgets".
So, this blog will from now on tell more about products and achievements of this new e-Creature, which I hope to grow fast to the size of my passion and enthusiasm!
Check it out regularly, we'll do our best not to disappoint you :)

Michele
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Skytraq s1315f-raw (under the magnifying lens)

April 10, 2011, 10:01 am
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Hi,

Lately I have been working with one of the few mass market receivers which outputs raw observables: the Skytraq S1315F-RAW. The only other "low cost" alternative to it is the uBlox LEA-4T, LEA-5T, and LEA-6T.

My purpose was to assess its capabilities, to understand if there are applications in which this device can really be useful. I don't know the answer yet, but I can publish some preliminary results obtained with RTKLIB.

So, I assembled a few of these on a board together with a FT232RQ UART-to-USB transceiver and run Cutecom on my Linux machine.

Figure 1: Yuan10 20-Hz raw measurements GPS receiver.

To my surprise, this does not work like the uBlox chips, which can output both NMEA and binary. The S1315F-RAW only outputs binary data. The news you don't read anywhere else is that the observations are taken at 20Hz, and do not include a PVT solution. Also, the clock bias is let running free and therefore the measures can be quite far off (tens of milliseconds) the real GPS time.

Ultimately I wanted to know what is the quality of the carrier phase, since this will tell if the receiver is fit for low-cost RTK applications.


Scenario 1: Zero Baseline, Open Sky

Figure 2: Zero baseline track results in 1 hour.

Figure 3: Zero baseline ENU results in 1 hour.

Scenario 2: Short (known) Baseline, Open Sky
To be done still :)

Comparison 1: Orcam GPS-26 OEM (SiRF Star II)
Using the board below I collected RAW observables (pseudorange, carrier phase, Doppler, and C/N0) from two SiRF Star II receivers.

Figure 4: Dual SiRF Star II receiver board assembly
I wrote a simple SiRF binary to Rinex3 parser and the observations look like:

> 2011 04 08 17 23 47.7684297  0  8                                            
G26  50696315.376     1063480.948       91453.281          46.500              
G17  51072993.018     1467528.376       86392.422          43.500              
G27  48803613.805     2145210.883       87538.367          48.000              
G09  48571516.433      925322.182       85910.797          50.000              
G22  51765421.846     1955361.390       86170.438          40.800              
G12  51568741.123      921796.354       84204.570          42.900              
G28  51649721.912     1347484.069       90745.469          42.900              
G15  48654575.927     1362007.686       89023.945          53.800              
> 2011 04 08 17 23 48.7684297  0  8                                            
G26  50713719.228     1154933.716       91452.766          46.000              
G17  51089432.729     1553920.546       86392.164          43.000              
G27  48820272.359     2232748.763       87537.875          47.900              
G09  48587864.077     1011232.602       85910.422          50.400              
G22  51781819.554     2041531.555       86170.164          41.000              
G12  51584765.483     1006000.356       84204.008          42.900              
G28  51666990.473     1438229.023       90744.961          42.900              
G15  48671516.093     1451031.430       89023.742          53.300              
> 2011 04 08 17 23 49.7684297  0  8                                            
G26  50731122.086     1246383.916       91450.203          46.000              
G17  51105869.630     1640310.413       86389.867          43.000              
G27  48836930.232     2320284.139       87535.375          48.000              
G09  48604211.074     1097140.644       85908.039          50.000              
G22  51798218.833     2127699.431       86167.875          40.900              
G12  51600789.059     1090201.716       84201.359          42.700              
G28  51684257.464     1528971.343       90742.320          42.600              
G15  48688455.438     1540052.871       89021.438          53.000              
> 2011 04 08 17 23 50.7684297  0  8                                            
G26  50748523.408     1337830.931       91447.016          46.300              
G17  51122307.805     1726697.388       86386.977          43.100              
G27  48853586.988     2407816.398       87532.266          48.100              
G09  48620558.438     1183045.689       85905.047          50.000              
G22  51814616.209     2213864.420       86164.992          40.800              
G12  51616810.906     1174399.828       84198.109          42.300              
G28  51701524.646     1619710.464       90739.117          43.000              
G15  48705394.801     1629071.432       89018.555          53.000                

but unfortunately RTKLIB refuses to process the raw measurements and I am still trying to work out why!

Anyway, the first results with the S1315F-RAW seem promising enough, showing 2-3 cm errors in Kinematic mode. More will come on this post soon.

Cheers,
Michele
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The benefit of Glonass?

April 10, 2011, 3:38 pm
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Another study I am carrying out is how much benefit the availability of Glonass satellites really brings. Low-cost dual constellation GPS-Glonass standalone receiver are starting to show up in the market: Skytraq released the S4554GNS-LP and the S2525G2F, and NVS is soon coming out with their NV08C.

Well, I assembled a few S455GNS-LP on a carrier board:

Figure 1: Kopeke10 USB GPS-GLonass receiver
..and drove in the countryside doing some tests.

Figure 2: Test drive with two dual constellation antennas: a non-branded one (20EUR, left) and a Tallysman TW2400 (80EUR, right).
On the left antenna I had:
- a S1315F-RAW
- a S4554GNS-LP

on the right antenna I had:
- a uBlox LEA-5H evaluation kit
- a S1315F-RAW
- a S4554GNS-LP

So that I would make sure to test my receivers with both antennas and compare them against a good reference. Some preliminary results are shown below.

Figure 3. The roundabout is always good to test how much filtering the PVT solution has. Considering that Google Earth might not necessarily be super-accurate, all the receivers perform pretty well.
 
Figure 4. Driving under a big junction does not affect the receivers very much. Well done!

Figure 5. Uhm? What the heck is that? The Skytraq receiver obviously picked up quite a bit of multipath from the South-East building when I stopped. The good LEA-5H -on the same antenna- did not make a move, and neither the other S4554GNS-LP.



Figure 6. Approching a parking slot just after the road bends, running along a bunch of trees. Multipath has again an interesting different effect on the receivers. But I am more likely to have parked where the uBlox said :)

I will soon add some results in urban environment, where having twice as many satellites should make a real difference.


EDIT 26/08/2011:
Recently, I went out again to compare data from the Sytraq S455GNS-LP and a NVS NV08C-CSM which I soldered onto a carrier board called Denga10 (shown below). The antenna was a low-cost GPS/Glonass magnet-mount patch.

Figure 7. Denga10 carrier board for NV08C-CSMGPS/Glonass receiver.


NVS provides easy software to manage their receivers and translate what is a unconventional NMEA stream:

$GPGGA,203211.00,4340.7619,N,01020.8364,E,2,14,00.8,002.0,M,47.9,M,,*59
$GPRMC,203211.00,A,4340.7619,N,01020.8364,E,00.00,218.2,020811,,,D*5B
$GPGSV,4,1,13,03,65,155,48,06,53,140,47,11,32,282,44,14,24,117,41*7D
$GPGSV,4,2,13,16,19,193,46,18,22,048,41,19,77,307,49,22,58,066,48*7B
$GPGSV,4,3,13,24,21,268,41,32,14,210,40,33,33,214,43,37,38,164,41*7A
$GPGSV,4,4,13,39,37,159,00*48
$GLGSV,2,1,06,66,55,046,46,73,09,307,24,74,05,353,20,81,52,106,38*6C
$GLGSV,2,2,06,82,62,338,44,83,12,313,01*6D
$GNGSA,A,3,03,14,19,06,24,32,22,16,11,18,,,01.3,00.8,01.0*16
$GNGSA,A,3,66,73,82,81,,,,,,,,,01.3,00.8,01.0*10
$PORZD,A,002.8*36

Figure 8. Navis converter to generate a KML from the GPS/Glonass NMEA output of the NV08C-CSM
Also Skytraq is working hard and recently added a GNS Viewer to their software in order to allow customers to quickly evaluate what is again a non conventional NMEA stream:

$GNGNS,203211.170,4340.7630,N,01020.8350,E,AA,16,0.7,14.1,45.7,,0000*53
$GNGSA,A,3,03,06,22,14,18,19,24,32,11,16,,,1.1,0.7,0.9*23
$GNGSA,A,3,66,81,82,73,65,74,,,,,,,1.1,0.7,0.9*25
$GPGSV,3,1,12,19,77,308,49,03,65,155,49,22,58,067,48,06,54,141,46*7B
$GPGSV,3,2,12,11,32,283,44,14,24,118,40,18,23,049,41,24,21,268,40*71
$GPGSV,3,3,12,16,19,194,46,32,14,210,40,28,02,333,,08,00,299,*79
$GLGSV,3,1,09,82,62,338,44,66,56,047,47,81,52,106,37,83,12,314,15*6C
$GLGSV,3,2,09,73,10,307,24,74,06,354,32,65,05,030,32,88,03,125,*6D
$GLGSV,3,3,09,80,00,261,*51
$GNRMC,203211.170,A,4340.7630,N,01020.8350,E,000.0,221.9,020811,,,A*7B
$GNVTG,221.9,T,,M,000.0,N,000.0,K,A*1B

Figure 9. Skytraq GNS Viewer.
Some results are shown below. Seems that the NVS tends to filter a bit too much. Luckily it's possible to upgrade the firmware of these receivers and hopefully NVS has already worked on it to improve accuracy.






Figures 10. The NVS receiver tends to filter too much compared to the Skytraq.

EDIT 07/12/2011: NVS released recently a new firmware for their NVS08C-CSM. I will update Denga10 and have another test session very soon!

Questions?

To be continued (again),
Michele
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Is SiRF really bringing back carrier phase?

August 29, 2011, 12:48 am
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Lately I have been witnessing people reporting about getting carrier phase from various SiRF GSD4e receivers, such as Navman and OriginGPS. 
There is a moltitude of SiRF IV receivers out there, and the list below is not exhaustive:


Fastrax IT430
Maestro Wireless A-2100
Inventek ISM420

Wi2Wi W2SG0084i

Micro-modular MN8010
OriginGPS ORG4472

Locosys Technologies S4-0606
Navman Wireless Jupiter J-F2

Thanks to Димма on a Russian Geodesy blog, we have a snapshot of data collected with SiRFLive2.0 (please forgive text wrapping):


SiRFLive Version: SiRFLive 2.0 Marketing
Thursday, August 25, 2011
PC: W037D299
Physical Connection: UART
SW Version: GSD4e_4.1.0-P1 12/20/2010 354 GSD4e
DUT Name:
28,0,860041386,25,3.8972801716003340e+005,2.5330147020331487e+007,1.8319525e+004,2.5330178622016661e+007,30000,191,27,27,27,27,27,27,27,27,27,27,1000,500,-4,0,0
28,1,860041386,12,3.8972801716003340e+005,2.6510500006031543e+007,1.8745631e+004,2.6510516541034564e+007,30000,191,44,44,44,44,44,44,44,44,44,44,1000,500,-4,0,0
28,2,860041386,2,3.8972801716003340e+005,2.7095735858978566e+007,1.8233168e+004,2.7095742224695239e+007,30000,191,45,45,45,45,45,45,45,45,45,45,1000,500,-4,0,0
28,3,860041386,4,3.8972801716003340e+005,2.8811696972083870e+007,1.8818879e+004,2.8811729208855990e+007,30000,191,43,43,43,43,43,43,43,43,43,43,1000,500,-4,0,0
28,4,860041386,10,3.8972801716003340e+005,2.9933113007417683e+007,1.7881320e+004,2.9933150167102419e+007,30000,191,41,41,41,41,41,41,41,41,41,41,1000,500,-4,0,0
28,5,860041386,30,3.8972801716003340e+005,2.5056555168215591e+007,1.8287135e+004,2.5056605592962816e+007,30000,45,15,15,15,15,15,15,15,15,15,15,1000,500,0,50,0
28,6,860041386,31,3.8972801716003340e+005,2.7253274315252494e+007,1.7911645e+004,2.7253302286751069e+007,30000,45,21,20,20,20,20,20,20,20,20,20,1000,500,-4,50,0
64,2,25,16,2,0,860046711,2711796546,-2018378871,202101184,34,13,19486396,161,170064,14592,765,5295,127,0,373,37,19486200,8,0,0,1
64,2,12,16,2,0,860045683,2711665022,-999316371,206803073,-1,9,19486396,93,88983,14592,243,263,236,0,419,19,19486200,6,0,0,1
64,2,2,16,2,0,860044900,2711564712,590426562,201150408,2,7,19486396,58,34257,14592,209,-410,237,0,471,15,19486200,9,0,0,1
64,2,4,16,2,0,860056748,2713081329,-637293933,207611290,1,2,19486396,178,173482,14592,200,328,229,0,384,20,19486200,9,0,0,1
64,2,10,16,2,0,860052503,2712537904,-712001231,197268336,1,65534,19486396,206,199974,14592,-294,-424,231,0,340,16,19486200,14,0,0,1
64,2,30,16,6,0,860048142,2711979654,-68870448,201744724,2,14,19486396,265,271360,14592,-1060,2049,-30,0,108,130,19486200,0,-1,0,1
64,2,31,16,6,0,860053502,2712665770,-161848563,197604358,5,7,19486396,147,150528,14592,2103,-464,-38,0,83,165,19486200,8,0,0,1
30,25,3.8972799999998091e+005,1.5076749765686795e+007,3.5933861764103957e+006,2.1542989468968987e+007,6.4299937762260811e+001,2.7401660794328523e+003,-4.9865148201605086e+002,1.5608991872749377e-005,1.5621511e-012,1,0.0000000e+000,0.0000000e+000,3.2923935e+000
30,12,3.8972799999998091e+005,1.1884563679683834e+007,1.6291456387266476e+007,1.7384876625289034e+007,-1.1622553644346129e+002,2.1962242709684892e+003,-1.9626822261160808e+003,1.8102194566119174e-005,3.3094907e-012,1,0.0000000e+000,0.0000000e+000,4.2158856e+000
30,2,3.8972799999998091e+005,6.2082524729776531e+006,1.8408282380763520e+007,1.8385535284110300e+007,-2.1201026021377620e+003,-9.3213884708925502e+002,1.6059507862227920e+003,3.5292745438883114e-004,4.0546915e-012,1,0.0000000e+000,0.0000000e+000,4.7821899e+000
30,4,3.8972799999998091e+005,-1.0762067066920688e+007,1.1736652988876456e+007,2.1071583778895516e+007,-2.3825680363444444e+003,-1.3365420890936439e+003,-4.3364700696691807e+002,2.1170121762251255e-004,9.2645414e-012,1,0.0000000e+000,0.0000000e+000,6.5737190e+000
30,10,3.8972799999998091e+005,-9.8302346586159449e+006,2.0084912631979931e+007,1.3816020695044205e+007,-2.8794790172300321e+002,-1.8082575793544818e+003,2.4235822198007645e+003,-1.1038774409012209e-005,-4.5888042e-012,1,0.0000000e+000,0.0000000e+000,9.3115501e+000
30,30,3.8972799999998091e+005,1.5365798544428909e+007,2.2397196288039838e+006,2.1188563043022357e+007,3.0218839841904361e+002,2.7624647015425176e+003,-5.0214592859035730e+002,9.1548491532589152e-005,-3.8803110e-012,4,4.0960000e+005,1.0816000e+004,3.2914379e+000
30,31,3.8972799999998091e+005,7.1807381854674015e+006,-1.3033520067140032e+007,2.2198544705630817e+007,2.4188392313643085e+003,1.3389951664065002e+003,2.4421316559121053e+001,1.3109461800722862e-004,9.3347006e-012,4,4.0960000e+005,1.0816000e+004,4.2912688e+000
41,0,516,1650,389728000,2011,8,25,12,15,13000,16779786,577739216,142115489,22129,18638,21,0,19942,0,0,0,2504,2291,0,1,514445417,0,1830720,0,0,0,0,5,23,8
4,626,38972800,12,2,86,42,191,46,46,45,45,45,45,45,45,45,45,10,62,6,191,41,41,41,41,41,41,41,41,41,41,12,107,50,191,44,44,44,44,44,44,44,43,43,43,30,219,83,45,15,15,15,15,15,15,15,15,15,14,4,38,18,191,44,44,43,43,43,43,43,43,43,43,25,185,85,191,27,27,27,27,27,27,27,26,26,26,31,300,40,45,21,21,21,21,20,20,20,20,20,20,29,215,50,0,0,0,0,0,0,0,0,0,0,0,14,240,16,0,0,0,0,0,0,0,0,0,0,0,9,156,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
2,3305164,837044,5372540,0.000,0.000,0.000,4,4.6,2,626,38972800,5,25,12,2,4,10,0,0,0,0,0,0,0
9,0,0,0,0
7,1650,389728,5,96205,17160052,389727999
50,0,0,18,0,0
As this is a fantastic opportunity for people looking for a cheap RTK system, I am planning to have a further look into this. Any help and comments are appreciated!

EDIT 11/09/26:
I assembled Shilling20, a dual Origin GPS ORG4472 board

Figure1: Dual GSD4e (ORG4472) assembly, for short baseline applications.



And seems that both receivers, with firmware  
GSD4e_4.0.4-P1 08/13/2010 225 GSD4e
Output RAW measurements: pseudorange, carrier phase, Doppler, etc. MID64.2 is also preent. More to come soon.

Cheers,
Michele
 
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NVS08C-CSM, the first mass market receiver to track Galileo

December 26, 2011, 11:19 pm
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I would like to report the great work done by NVS which -to my knowledge- is the first Company to produce a mass market single frequency four constellation receiver tracking Galileo.

Figure 1: NVS Storegis displaying simultaneous tracking of GPS, Glonass, and Galileo PRN11 (in yellow).

The receiver was flashed with a custom firmware kindly provided by the manufacturer to us on Boxing Day and was then perfectly able to track GALILEO-PFM (GSAT0101). Elevation and azimuth are -obviously-
not measured as the satellite transmits dummy data and it's therefore marked as unhealthy right now.

Other bespoke versions of the firmware enable tracking of GIOVE A and B or raw observables on all constellations, which shows the potential of this little module.

Another good thing is that the NVS08C-CSM is easily available for purchase through NVS reps as well as here:
http://it.farnell.com/nvs-technologies/nv08c-csm/receiver-sat-navigation-smt/dp/1902504

Merry Christmas to all the GNSS community!

All the best,
Michele

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Processing Galileo

January 1, 2012, 5:25 am
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The first prototype of SdrNav20 is working these days to receive the Galileo signal in space.

Figure 1: First SdrNav20 assembled prototype.


Using a simple patch antenna, the first acquisition done using a 8MHz bandwidth reports the expected spectrum purity and signal properties.
Figure 2: Power spectrum of signal acquired on SdrNav20 channel 1. A bandwidth of 8MHz is wide enough for BOC(1,1), but not CBOC(6,1,1/11). A bandwidth limitation is anyway introduced by the antenna SAW filter as well.
Figure 3: Time series and histogram of the acquired signal. The gain of the satellite tuner was set to 60dB (RF) and 8dB (IF), which could not excite the second MSB of the MAX19505 ADC.

The acquisition of Galileo PFM shows the typical BOC(1,1) correlation shape.:
Figure 4: BOC(1,1) correlation shape, averaged on 100 codes (400ms).
A short file (for anybody to try his/her own acquisition) can be found here.

EDIT 27/12/2012: Acquiring with SdrNav20 Galileo-FM2 (Galileo-PFM seemed momentarily disabled)
Figure 5: Galileo-FM2 E1 correlation shape, averaged on 100 codes (400ms).
The messages on E1B looked good, but still dummy:

a98e40000000002aaaaa4f4f2ffb8000
00955555555555555555555544790000
a98ec0000000002aaaaa5063173b8000
3f4a63d11ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f83b4db6d54000
3f4a63f11ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f803cb10954000
3f4a64111ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f8225d9ad54000
00955555555555555555555544790000
a990c0000000002aaaaa4823ab3b8000
00955555555555555555555544790000
a99140000000002aaaaa6957e27b8000
3f4a64711ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f80a454ed54000
3f4a64911ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f803617e554000
3f4a64b11ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f83be7d8154000
3f4a64d11ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f813ff0c154000
3f4a64f11ea372ec4d3b4f84dcbb0000
934ed3e1372ec4d3b4f82b79aa554000
00955555555555555555555544790000
a99440000000002aaaaa6d48287b8000
00955555555555555555555544790000
a994c0000000002aaaaa726410bb8000
00955555555555555555555544790000
a99540000000002aaaaa531059fb8000
d3978d7c6c2e85281e379780ce9f8000

A sample file is here.

Adding to the above, SdrNav20 demonstrates acquisition of L2C and L5 (or Galileo E5a):
Figure 6: Power spectrum of L2C signal captured with SdrNav20
Figure 7: Signal acquisition of GPS L2C signal (only of enabled PRNs)
Figure 8: Power spectrum of L5 signal captured with SdrNav20

Figure 9: Signal acquisition of GPS L5 signal (only of enabled PRNs) 
Figure 10: Signal acquisition of Galileo-PFM on E5a
A couple of files for L2C and L5 are stored respectively here and here. Please mind that L2C acquisition (without assistance) can be a long process given the length of the codes :)

Cheers!
Michele

P.S.: The file name is self-explicative: fs is sampling frequency, fif is intermediate frequency, bw is bandwidth, interleaved I&Q has 'int8_t' type samples (pretty much as the GN3Sv2 used to output).
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