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|T O P I C R E V I E W
||Posted - 20 mars 2005 : 16:36:53
UPDATED20101201SiRFdemo for PCs (and PocketPCs*)
Advanced configuration for SiRF based GPS receivers!
>> SORRY THE PICTURES HAVE BEEN LOST
EXPLANATIONS SHOULD STAND BY THEMSELVES
IF NOT FEEL FREE TO ASK ANY QUESTIONS <<
Before proceeding, download the latest version of SiRFdemo
PC Version (advanced) : v3.87 - PPC Version (basic): v1.16
- Navigation Parameters
- Configuring 'Static Navigation'
- Back to NMEA
- Links of interest
Why use SiRFdemo ?
- 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
- Your GPS is behaving oddly and you want to reset it to factory defaults
- 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
- 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
- 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
- Launch SiRFdemo - choose the correct COM port and select 4,800 (or 38,400 for a Bluetooth GPS) (fig 1)
- 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
3. NAVIGATION PARAMETERS
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 :
- Operating Mode (Degraded/Altitude Hold/Dead Reckoning) : défines the operating mode when optimal reception (4+ satellites) is no longer available
- 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
- 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
- DOP : filtering based on the quality of reception
- 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
- 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.
4. STATIC NAVIGATION
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 :
- \Navigation\Static Navigation\ (fig. 6)
- Click on "Disable" then SEND (fig. 7)
- Verify that the change has been recorded by the GPS by calling the Navigation Parameters
- Please note that the default setting will return with a "factory reset" command or when the battery runs out
- 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
5. BACK TO NMEA
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:
- To keep your settings : \Action\Switch to NMEA Protocol\ select 4,800 then Send (fig. 10 et 11)
- To set your GPS back to its factory settings : \Action\Initialize Data Source\Factory Reset then Send (fig. 12 et 13)
6. USEFUL LINKS
- "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.
Discounts and Assistance/Réductions et Assistance (Club GpsPasSion) / Où commencer?
|15 L A T E S T R E P L I E S (Newest First)
||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.
||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).
||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:
thanks in advance,
||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).
||Posted - 26 janv. 2011 : 22:26:37
Do you know where I could get the other SIRF tools (SiRFGetEE, SiRFView...) ?
||Posted - 26 janv. 2011 : 13:43:33
SirfTech works fine. I also managed to run SiRFDemo 3.87 from my laptop through ActiveSync. For this I use :
- Franson GPSGate 18.104.22.1687 on the laptop (input = ActiveSync)
- Franson GPSGate 2.6 build 347 BETA for Windows CE .NET on the device (output = activesync)
||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:
||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 sirf.com 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...
||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
||Posted - 30 oct. 2009 : 11:29:19
just for the knowledge base:
transmit serial message:
sirf mode: PSRF100,0,38400,8,1,0
nmea mode: A0A20018 81020101 00010101 05010101 00010001 00010001 00019600 012BB0B3
||Posted - 05 juil. 2009 : 08:55:31
i try 2400 that work the nmea protocol in the other baudrate i can't view the nmea string
When i try to change protocol i obtain only this
in error view
warning setcommstate()failed in CSerialComm::open
warning SetComm(0x1000)() failed
i have an other question, the 1 PPS output it's enable when there is the fix or must be enable by sirfdemo ? because i have wired the probe of the oscilloscope but there isn't the 1pps signal !
||Posted - 04 juil. 2009 : 23:41:45
Originally posted by scalor
only this string in the receiver output view
255(0xFF) Error Data
and in the error view
Did you try every possible baudrate at this point?
||Posted - 04 juil. 2009 : 21:38:28
i have a problem, in a usglobalsat mr350P gps that work perfectly in nmea output, when i try to switch between nmea output and sirf output, i obtain only this string in the receiver output view
255(0xFF) Error Data
and in the error view
||Posted - 20 mars 2009 : 20:28:03
No chance, not sure what your problem is, but you should check out the topics in the Garmin section for tips on how to fix it.
||Posted - 20 mars 2009 : 20:25:28
does anybody know how to connect to a garmin c550 using this software and usb or bluetooth? My sirf firmware needs a downgrade since webupdater did me in. I tried installing sirfdemo & the uart/usb software
I get error code 10 just trying to start the driver.
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