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 SiRFdemo tutorial (static navigation)

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T O P I C    R E V I E W
gpspassion Posted - 20 mars 2005 : 16:36:53
SiRFdemo for PCs (and PocketPCs*)
Advanced configuration for SiRF based GPS receivers!


Before proceeding, download the latest version of SiRFdemo
PC Version (advanced) : v3.87 - PPC Version (basic): v1.16


  1. Introduction
  2. Configuration
  3. Navigation Parameters
  4. Configuring 'Static Navigation'
  5. Back to NMEA
  6. Links of interest


Why use SiRFdemo ?
  1. To take a peek at the advanced settings of your GPS receiver and to see how it was set in the factory, or modify some of these settings

  2. Your GPS is behaving oddly and you want to reset it to factory defaults

  3. You want to verify the revision of the Firmware loaded on your GPS receiver - (insight on SiRF FW naming)

<!> Beware <!>
While using this software will normally not damage your receiver, please realize that some actions not covered in this tutorial might misconfigure your receiver and likely void your warranty. In any case, GpsPasSion will not be held responsible if your GPS receiver stops responding from the use of this software


  1. To use SiRFdemo you need a PC or a laptop and a way to connect your GPS receiver. For a compact flash GPS, you can use a PCMCIA/CF adapter, for a wired GPS, a DB9 serial port or USB via a USB/DB9 adapter and of course a Bluetooth GPS receiver with built-in BT or a dongle
  2. You need to identify the correct COM port used by your GPS. It will be COM1 for a serial GPS generally and for a Bluetooth GPS, a right click on the connection will show you the port
  3. Launch SiRFdemo - choose the correct COM port and select 4,800 (or 38,400 for a Bluetooth GPS) (fig 1)
  4. SiRFdemo only provides detailed information in SiRF mode so do \Action\Switch to SiRF (fig 2) and you will see the various windows "light up"(fig 3)

Fig.1 Fig.2 Fig.3


A modern GPS receiver is a full blown "computer" equipped with a CPU - baseband chip (ARM), an RF chip (signal processing), ROM (rewritable flash) and RAM - but unlike a "normal" computer it is highly specialized and has been programmed accordingly. Some of these parameters are visible as the "Navigation Parameters"; to make them appear in the "Response View" window, do \Poll\Navigaton Parameters. Let's take a brief look at them :

Fig.4 Fig.5

  1. Operating Mode (Degraded/Altitude Hold/Dead Reckoning) : défines the operating mode when optimal reception (4+ satellites) is no longer available
  2. Track Smoothing : wrill smoothen the track to remove the "jumps" resulting from the natural "inaccuracy" of the GPS system (10/15 meters) - disabled by default
  3. Static Navigation : will "freeze" the position at very low speed to cancel out the drifting resulting from the natura "inaccuray" of GPS - should be disabled for pedestrian use - see below for details
  4. DOP : filtering based on the quality of reception
  5. DGPS : controls the activation of SBAS (WAAS in the US and EGNOS in Europe) - since SA (Selective Availability) was removed in May 2000, mainly useful to check the integrity of the GPS signal for critical use in planes and in shipts - available on SiRFstar III with FW 3.1 and above
  6. Power : to configure power saving trickle modes

Note : To show the firmware version loaded in your GPS in the top window, do \Poll\SW Version - GSW3.0...with the SiRFIII Globalsat BT-338 GPS I was using.


While most settings are best left untouched unless you want to experiment (always risky !), "Static Navigation" is one that should be looked at closely especially with the arrival of the new SiRFstarIII based receivers, as these ultra-powerful receivers take GPS reception to a new level and can work with very weak signals but when that happens, accuracy can be impacted. Observations over a 24 hour period show that with good signals, 95% of the positions reported by the GPS will be within a 15 meter radius, while with weak signals, 95% of the positions will be within a radius of 50 meters.

Current road navigation software is designed for GPS receivers that only operate with good signals so accuracy will be in the 15 meter area. Such software will "snap" the position to the closest road so in a dense urban area, with degraded accuracy it's going to be easy to make the wrong decision and produce "uncosmetic" results and possibly force a trip recalculation.

Instead of redesigning navigation software to take this account (one could imagine some type of dynamic filtering based on DOP) and risk increasing the processing load on the PDA and hurt user experience, the easy fix is to implement this fix directly by having GPS manufacturers activate "Static Navigation" by default and therefore freeze the position using some complex algorithms mainly speed dependent. The problem with this is that this will considerably hurt low speed pedestrian use, with the speed staying on "0" and 50 meter jumps (update threshhold). If you want to use your GPS receiver outside your car, you'll need to disable SN, this is how to do it :

Fig.6 Fig.7

  1. \Navigation\Static Navigation\ (fig. 6)
  2. Click on "Disable" then SEND (fig. 7)
  3. Verify that the change has been recorded by the GPS by calling the Navigation Parameters
  4. Please note that the default setting will return with a "factory reset" command or when the battery runs out
  5. Analyzing: As you can see in 9a, representing a walk with silumtaneaous logging, the impact of SN on a SiRFstarIII GPS is pretty significant, better accuracy, better distance measurement, with Xtrac 2 there is no notable impact and its status as a "non-pedestrian" friendly GPS remains.

BEFORE - AFTER - On the Field

Fig.8 Fig.9 Fig.9a


NMEA being the universal GPS language, best not to forget to return to that mode after looking up the advanced settings and possibly modifying them. There are two ways to proceed:
  1. To keep your settings : \Action\Switch to NMEA Protocol\ select 4,800 then Send (fig. 10 et 11)
  2. To set your GPS back to its factory settings : \Action\Initialize Data Source\Factory Reset then Send (fig. 12 et 13)

Fig.10 Fig.11

Fig.12 Fig.13


  1. "Technical Forums" - >>HERE<<

* PocketPC owners can also try this application that I have found to work as well although not with WM2003SE. For WM2003SE you can use this program to toggle SN and also or CE Monitor and GPSTweak for SBAS settings - 02/2006 : here is a new "tweaker", SiRFtech.

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15   L A T E S T    R E P L I E S    (Newest First)
zgroza Posted - 16 juil. 2013 : 23:15:09
(it's hard to believe to me, but it really works)

I've found a solution by accident, on a one of Polish biker's blog. That man wrote: "when you connect with SirfDemo in NMEA mode, select: Transmit serial message, type: PSRF100,0,9600,8,1,0 and choose NMEA protocol wrapoer" - and when I've done this, I saw at last standard behavior described on this forum (and many others): flowing output in the response view...

I don't understand how it works (and why option "switch to Sirf protocol" doesn't work) but it doesn't matter to me: finally I could switch off StaticNav., switch on SBAS - and poll Nav parameters to make sure that it works.

If it would be useful to anyone of you: I've checked first communication with SirfTech for PC - and I was able to switch to Sirf without problem & switch off StaticNav. - but I wasn't sure the result: I couldn't find an option to check if this command was completed succesfully. And next thing: both SirfDemo and SirfTech, when used with PortMon running (thanks for remind me, that such application exist), show, that communication occur all the time until I disconnect the device: even when SirfDemo shows nothing after switching to Sirf protocol (choosen from menu "action"), PortMon still shows, that everything is ok. - all commands (synchronizing baud rates etc.) are completed with success! Only SirfDemo shows no output... I don't understand this (I'm not a programmer) and I don't even try: I'm really happy that my module works fine :))) (and yesterday I thought of throwing it away...)

Anyway, thanks a lot for your help :)))
zgroza Posted - 15 juil. 2013 : 09:14:20
Thanks a lot for your replies!
Unfortunately today I left the receiver at my friend for further testing (I don't expect anytning), I'll have it back tomorrow and then I'll follow your advices.

I'll let you know if there's any progress or none (by the way: I didn't realize that there's a separate version of SirfTech for PC).
Carl@SiRF Posted - 12 juil. 2013 : 18:42:35
What you describe is pretty classic for losing baud rate matchup. The fact that the LED continues to blink means that the unit is still sending out data. When you command the unit to change protocol and baud rate, SiRFDemo does the same thing with you, so if the command was not acted upon for whatever reason, you lose communication.

There are a couple things that could be wrong: either the receiver rejected or did not act upon the command, or it responded incorrectly. That latter is not very likely, so let's concentrate no the former. The basic GSC3 chip has two serial ports, although one may not be connected. If the software in the receiver is set to handle both ports, then as a byproduct of that you are stuck without being able to switch protocols - there is a rule in the software that only one copy of a protocol may exist and in a two-port build NMEA is already on one port and SiRF binary is on the other. I suspect that is your issue.

To verify if that is correct, issue the command to switch baud rates only. If you keep contact with the chip, then issue the command to switch protocol but at the same baud rate. If the receiver continues to talk in NMEA, most likely the two-port build is the culprit and you can't switch to binary. Chect your module and see if maybe somewhere on the circuit board the other serial port is present - look with a scope on any test points for serial data.
saimhe Posted - 12 juil. 2013 : 17:46:25
After switching to Sirf protocol, nothing happens: GPS module behaves as if it was disconnected (green led blinking slowly), there's nothing in response view, in error view or receiver output view and when I try to send any command to the module I can't even check if anything was send.

Try the PC version of SirfTech ( It behaves more transparently than SiRFdemo. Additionally, you can run PortMon ( to see what was actually sent and received.
zgroza Posted - 12 juil. 2013 : 13:56:06

Need some help if you can :)
I've tried to disable Static Navigation (Nokia LD-3W; SirfDemo 3.87 & earlier, e.g. 3.30a, 3.36, 3.40 - no difference) with no result. I can connect with GPS module and I have output in debug view (NMEA protocol behaves as if everything was ok.), but when I switch to Sirf Protocol - I'm loosing connection with the module (when I switch back, I have output in debug view again). After switching to Sirf protocol, nothing happens: GPS module behaves as if it was disconnected (green led blinking slowly), there's nothing in response view, in error view or receiver output view and when I try to send any command to the module I can't even check if anything was send. The only thing that changes is baud rate: always 57600 (yes, I switched "set main serial port" settings - with no effort). I've tried to log in if anything changes, but there's nothing valuable in the log file). Receiver initialization doesn't make any changes too.

I've tried to solve it by myself:
First of all, I've read SirfDemo User Guide (trying to find some troubleshooting or some hints to my problem) - nothing found. Then, I've read this forum to find any solution - the only hint I've found was to install Alpsirf on PocketPC - but I haven't got any... only standard PC (and mobile phone running java apps). I've tried to change bluetooth COM port number and other settings, change bluetooth drivers (Widcomm & Bluesoleil, on different PC's), I made reset of GPS receiver (on the device - software can't do it), in SirfDemo: I made protocol & baud rate synchronization, tried to set different baud rates by hand, switched on (or off) time sync, changed target software (I don't know which version my Nokia has) with or without auto-detection. And no result: always the same. I feel helpless...

GPS module is brand new (with valid warranty). And it has no other sockets to connect - only bluetooth.

Is there something I could omit?
Can you at least tell me for sure, that my GPS module is damaged? That would be usefull.

Thanks a lot in advance :)
Carl@SiRF Posted - 23 avr. 2013 : 01:54:42
The message that says Unk: 4002131400........00000002 means that SiRFDemo has parsed a binary message, removing the header and trailer, but that it doesn't know how to interpret the payload. SiRFDemo has been replaced by SiRFLive for newer chips like the GSD4e, so it was never taught how to interpret message ID 64, subID 2 (0x40 0x02 for the first two bytes).

MID 64 is the new message group of advanced navigation library data.
saimhe Posted - 12 nov. 2012 : 19:05:21
Not enough data. With some 1-2 KB it would be easier.

Basically this message means that SiRFDemo was unable to detect neither NMEA format nor SiRF binary format. To my eyes this definitely isn't NMEA, too many non-text values. As for the binary, the protocol allows to craft a packet that's 32 KB in length and still valid, and a packet boundary would not be found earlier.

But in practice this is more similar to a bitrate mismatch. SiRFDemo likes to switch to higher bitrate among with the binary protocol. Some Bluetooth modems support a single bitrate only and in such case communication becomes impossible until the entire GPS receiver is reset properly (for example, by disconnecting the internal backup battery).
jeensii Posted - 25 oct. 2012 : 13:39:02

Can anybody explain to me what the output in sirf mode in the debug view of SiRFDemo exactly means? I mean those:

Unk: 4002131400........00000002

thanks in advance,
testerics Posted - 13 avr. 2012 : 12:23:56
There is a command line for changing "Message Rate" on NMEA? I want to start GSA=1 and GSV=1 on my Navigon with a script before launching the Primo or iGO8 to have the possibility to see the signal bars on this applications (for now, Navigon is starting only GGA and RMC).
JulienS Posted - 26 janv. 2011 : 22:26:37
Do you know where I could get the other SIRF tools (SiRFGetEE, SiRFView...) ?
JulienS Posted - 26 janv. 2011 : 13:43:33
Thanks Alan,
SirfTech works fine. I also managed to run SiRFDemo 3.87 from my laptop through ActiveSync. For this I use :
- Franson GPSGate on the laptop (input = ActiveSync)
- Franson GPSGate 2.6 build 347 BETA for Windows CE .NET on the device (output = activesync)
Allycat Posted - 25 janv. 2011 : 19:44:24

SiRFdemoPPC was intended to run with Windows Mobile and generally the "stripped down" Win_CE devices have too many software modules missing.

It depends what you want to do, but have you seen/tried "SirfTech" which manages most of the SiRF functions and has wider platform support:

Cheers, Alan.
JulienS Posted - 25 janv. 2011 : 19:16:10
Hi Everyone, and especially Carl@sirf if you're still there:
I'd need to run SirfDemoPPC on a windows CE 6.0. I could hardly download the software from the internet, as is not available anymore. I installed it, and it doesn't seem compatible with my OS. Is there a way to make it work ?
If someone has experience about this...
jukivili Posted - 07 déc. 2009 : 01:28:36
Nokia LD-4W (GSWLT3.2.5NOK_3.3.01.01-CL31B1.00):

"Action -> Switch to SiRF Protocol" works fine (bt link goes down, after reconnect it is running in sirf-mode).

"Action -> Switch to NMEA Protocol" does NOT work (bt/gps go out of sync, need to power cycle), but manual NMEA switch works with 0 baud.

"Action -> Transmit Serial Message...": a0 a2 00 18 81 02 01 01 00 00 01 01 05 01 01 01 00 00 00 01 00 01 00 01 00 01 00 00 00 93 b0 b3
bogdan.dumitru Posted - 30 oct. 2009 : 11:29:19
just for the knowledge base:
Nokia LD-3W
transmit serial message:
sirf mode: PSRF100,0,38400,8,1,0
nmea mode: A0A20018 81020101 00010101 05010101 00010001 00010001 00019600 012BB0B3

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