Google
  Web www.gpspassion.com


GpsPasSion LIVE!
www.flickr.com
This is a Flickr badge showing public photos from GpsPasSion Live !. Make your own badge here.

www.NaviBlog.com



Versions

Links/Liens




Portal/Portail
Rechercher

- -

Polls/Sondages
Sondage
Pour vous guider sur la Route :
GPS Mobile (SEM)
GPS Intégré
Smartphone
Autre
Voter  -  Résultat des votes
Votes : 2296




Club GpsPasSion
Soutenez le site!

USA: (US$)
EUROPE: (€)
Guide Paypal


GpsPasSion Forums
Home | Profile | Register/Enregist. | Active Topics | Search/Recherche | FAQ
Username:
Password:
Save Password
Forgot your Password?

 All Forums
 Advanced Topics
 Traffic Information (TMC)
 [GUIDE] Decoding the TMC Protocol (GNS°

Note: You must be registered in order to post a reply.
To register, click here. Registration is FREE!

Screensize:
UserName:
Password:
Format Mode:
Format: BoldItalicizedUnderlineStrikethrough Align LeftCenteredAlign Right Horizontal Rule Insert HyperlinkInsert EmailInsert Image Insert CodeInsert QuoteInsert List
   
Message:

* HTML is OFF
* Forum Code is ON
Smilies
Smile [:)] Big Smile [:D] Cool [8D] Blush [:I]
Tongue [:P] Evil [):] Wink [;)] Clown [:o)]
Black Eye [B)] Eight Ball [8] Frown [:(] Shy [8)]
Shocked [:0] Angry [:(!] Dead [xx(] Sleepy [|)]
Kisses [:X] Approve [^] Disapprove [V] Question [?]

  Check here to include your profile signature.
Check here to subscribe to this topic.
    

T O P I C    R E V I E W
BeamRider Posted - 28 oct. 2004 : 14:34:12
UPDATED 2009 : Detailed information posted by Camomille here on page 2.
Does anyone has specification for the GNS protocol 1.0 or 2.0?
I've done some reverse engineering from a tiny serial log I've found on the net, but I still miss commands from PDS/PC to the GPS unit to initialise and tune station.
I'll be very glad if someone has or can produce a long log file with TMC messages to test my TMC decoder: in my country I've TMC service but with a subtype of TMC messages only and I know that in Germany and UK service is complete.
Many thanks
34   L A T E S T    R E P L I E S    (Newest First)
SandyLake Posted - 01 juin 2011 : 09:05:21
jose-ramon, or anyone else, can you please post a download link for DecoRDS. Thank you.
phmartin Posted - 05 avr. 2010 : 20:59:15
Gpspassion: even if SIRF chips do not have RDS capabilities, devices use some extra $PSRF codes for their own purposes. See examples in my post in Nov. 2008 in this thread.
gpspassion Posted - 03 avr. 2010 : 02:02:26
It seems unlikely as $PSRF stands for "SiRF Proprietary" and I'm not aware of their chips including RDS capability.
rickgtx Posted - 02 avr. 2010 : 15:17:18
Can you tell if this is GNS protocol?
I have a Nokia 500. Initially I thought the TMC was disabled by the manufacturer for the US. When iGo 8 searches it pauses at COM-3 and GNS protocol, but never finds TMC hardware. I never got a response from COM3 until used the FM On command ($PFST,FMON) and got a continuous response with $FM strings and a few $RDS strings like this:
$FM,0,08750,008,100*08
$FM,0,08750,009,100*09
$RDS,F551A383EE915FA2*6F
$RDS,B80CBBF5030F7FEA*13
$RDS,00F60D4CEB5C12F1*1F
$FM,0,08750,008,0*09

TMC is on Comm Port 3 (COM3:) at 1200 baud.
The command $PFST,FMON starts the TMC responding
The command $PFST,CHANNEL,10590 sets the FM station to 105.9

What do these commands do?
Based on a search in the Smart2Go navigation program these might be the commands to the TMC port:
$PFST, [NEMA | BAND,0 | FMON | SEEK,1,20 | SEEK,0,20 | CHANNEL,xxxxx]
$PLTCM, [V | + | - | H2,x]
$PSRF121,x
$PSRF122 - $PSRF122,95.3 tune to 95.3 MHz? (Didn't work)
$PSRF123 [1,x | 0,x]
$PSRF126,2
$PSRF153, [rds2 | pw1 | reg,>|or|> | frq xx.x]

My WinCE 5.0 device does not support .NET programs even with MioPocket installed so DecoRDS does not work.

Thanks for any information!
grandpa Posted - 05 nov. 2009 : 19:50:29
using iGO on a c710 wich contains an fm4 gns chip.
iGO's FF 56 78 78 56 results in
in: 3F 00 00 56 05 1D 2E 06 05 3F

message FF 43 01 00 43 seems to report the producer:
in: 3F 47 4E 53 20 47 6D 62 48 3F (GNS GmbH)

iGO tunes with message FF 59 01 01 59 and gets two lines in response
in: 3F 00 00 59 00 6F 6B 00 00 3F
in: 3F 00 00 66 02 01 55 00 00 3F
The fifth byte of the second message (02) is the frequency igo tunes next to, after CC the value is 00.

When manual tuning is used iGO tunes with FF 73 52 05 73 reply is
in: 3F 00 00 73 52 01 55 00 00 3F
L_o_k_i Posted - 14 août 2009 : 13:34:41
To scan down, starting from xx:

command: FF 78 xx 01 78
answer: 3F 00 00 78 00 6F 6B 00 00 3F (to be confirmed!)
when scan stops: should be the same as scan up

This command has been found in Navigon.
beemer Posted - 30 juil. 2009 : 16:50:19
What I've found and tested about GNS with iGO and Navigon.
==========================================================

RDS-ON
======
RDS ON
FF(or 0x3F) 56 78 78 56
answ:3F 00 00 56 05 11 2D 07 03 3F
Unknown meaning of fields 4-8 (05 11 2D 07 03) ?
Two differnet answer found in real TMC device logs:
3F 00 00 56 05 11 2D 07 03 3F iGO
3F 00 00 56 06 07 30 08 03 3F José Ramón

RDS_OFF
=======
FF(or 0x3F) 53 78 78 53
-Dont answer, only empty buffer

Tunning
=======
FF(or 0x3F) 46 xx 05 46 Used by iGO
FF(or 0x3F) 46 xx 78 46 Used by GNS Test
FF(or 0x3F) 73 xx 78 46 Used by DecoRDS
Answ: 3F 00 00 46 xx yy zz 00 00 3F
xx = (char) dwCurrentFrequency / 100 - 875 ;
yy zz = (Not sure).
00 00 if there are no station
01 55 if there are station with or without RDS or TMC


SCANNING
========
FF 79 xx 01 79 scan from xx up
xx = (char) dwCurrentFrequency / 100 - 875 ;
Inmediate answer: 3F 00 00 79 00 6F 6B 00 00 3F
Answer when scan stop: 3F 00 00 66 ww yy zz 00 00 3F : Stoped on ww with yy zz result
yy = (char) dwCurrentFrequency / 100 - 875 ;
yy zz = (Not sure).
00 00 if no station found. Continues scanning automatically
01 55 if there are station with or without RDS or TMC


RDS/TMC messages
================
3F aa bb cc dd ee ff gg hh 3F
aa-hh Four RDS data blocks RDS



Hope helps in a future to someone. HyperGPS TMC virtual driver is based on this and works fine.
beemer Posted - 11 mai 2009 : 17:17:56
This thread has been very useful for me developing HyperGPS ( http://forum.xda-developers.com/showthread.php?t=512630 )that is currently capable of comunicating with iGO 8 in royaltek mode from an HTC PDA FM radio reciver based on flywhc@xda-developers user FM API, but I wonder if you have more deep information on Royaltek and/or GNS protocols.

For example, that information from user phmartin, does somebody have completed it a little more?
$RTRDS provides tuning information; the format is
$RTRDS,p1,p2,.....p11,p12*checksum
p1 is the tuned frequency (readable text)
p2 is the signal level, 0 to 15 (readable text)
p8 is the "block ratio", 0 to 100% (readable text). "block ratio" is the name used in the demo s/w ref. [5]
I dunno what the other parameters are supposed to mean

The idea is to make HyperGPS as compatible as I'll can with GNS and royaltek protocols.

TKS.



BeamRider Posted - 25 mars 2009 : 10:57:14
What about OpenTMC standard? It "should be" pretty well documented because but I can still find only Anaryllo docs like:

http://www.locosystech.com/download/oem/Open%20TMC%20V2.00-1.02pdf.pdf

That's more than enough to decode TMC on those devices. Is there someone that has such a device that can provide logs? (there are some blind spots to clear in the document)
phmartin Posted - 04 nov. 2008 : 23:33:51
The following is based on my experience with the Bluetooth GPS-TMC receiver Royaltek RTG-2000
I used the following references:
[1] SiRF Binary Protocol Reference Manual and SiRF NMEA Reference Manual
[2] Specification of the radio data system (RDS) for VHF/FM sound broadcasting in the frequency range from 87,5 to 108,0 MHz, European Standard EN 50067
[3] Coding protocol for Radio Data System — Traffic Message Channel (RDS-TMC) using ALERT-C, International Standard ISO 14819-1
[4] GPS Diagnostics V1.05 by CommLinx Solutions -PC freeware
[5] Royaltek TMC demo software for Pocket PC -PPC freeware
http://www.royaltek.com/FileDownload.php?dir=DownloadFile&file=TMC_Demo_PPC2003_1209717193.CAB

As indicated by Jose-Ramon in his post 3-3-2008 (point 7) the sentences are inserted between NMEA sentences.
All sentences (sent and received) start with $ and end with * followed by a checksum (checksum is defined in ref [1])

Three types of sentences are sent by the receiver: $PSRFTXT, $RTRDS, $RTTMC.

$PSRFTXT followed by a string: this is a text message, directly readable (example: $PSRFTXT,Ack Input...)

$RTRDS provides tuning information; the format is
$RTRDS,p1,p2,.....p11,p12*checksum
p1 is the tuned frequency (readable text)
p2 is the signal level, 0 to 15 (readable text)
p8 is the "block ratio", 0 to 100% (readable text). "block ratio" is the name used in the demo s/w ref. [5]
I dunno what the other parameters are supposed to mean

$RTTMC provides RDS messages; according to [2], the RDS protocol defines an RDS message as 4 blocks of 16 bits of data; an RTTMC sentence simply contains one RDS message.
the format is
$RTTMC,p1,p2,p3,p4,p5*checksum
p1 is the RDS group type (readable text) as defined in ref [2], the most interesting are
....0: basic information
....2: radio text
....4: clock time and date
....8: TMC traffic message channel
....14: EON Enhanced Other Networks
p2 is the Pid (programme identification code) in readable form. The Pid is defined in [2]; it always is the first block of any RDS message
p3, p4, p5 are three 4-character chains containing blocks 2 to 4 of the RDS message in Hexadecimal. Detailed definition of these messages can be found in ref [3] for group type 8 (TMC) and in ref [2] for the other groups.

The following sentences can be sent to the receiver: $PSRFxxx (SiRF binary messages, see ref [1]) where xxx can be 107, 121, 122, 123, 126. The receiver sends in response to sentence 121-126 an acknowledgement sentence $PSRFTXT,Ack Input121*checksum (or an error sentence $PSRFTXT,Nak Input121*checksum).
The purpose of the sentences is the following: (see ref. [5])

$PSRF107*21 Get firmware version. Response (with my device)
>>>>>>>>$PSRFTXT,VersionR: 2K00320101N10151006080906*42
>>>>>>>>$PSRFTXT,RoyalTek Ver 1.1.0.106 GSW3LP EE*74
>>>>>>>>$PSRF154,107*3D

$PSRF126,0*3F Set scan mode (see ref. [5]) to FM
$PSRF126,1*3E Set scan mode to RDS
$PSRF126,2*3C Set scan mode to TMC

$PSRF123,1,1*27 scan up
$PSRF123,0,1*26 scan down

The receiver will scan until it locks on any transmitter (if scan mode=FM), or until it locks on a station sending RDS messages (if scan mode=RDS), or until it locks on a station sending RDS group type 8 messages (if scan mode=TMC)

$PSRF123,1,0*26 tune up (ie increase the frequency by 0.1 Mhz)
$PSRF123,0,0*27 tune down

$PSRF122,freq*checksum tune to freq
example: $PSRF122,95.3*1B tune to 95.3 MHz
(Note: to perform tests without having to compute the checksums, s/w ref. [4] came quite handy to experiment sending these types of messages)

$PSRF121,p1*checksum still is unclear to me. It seems that sending $PSRF121,0*39 will memorize a Pid and that $PSRF121,1*38 will scan if the current Pid is different from the one in memory. That's an unconsolidated guess for the time being.

So this is where I stand. All questions are welcome. I hope others will pick up from here and complete the interpretation of the $RTRDS and the $PSRF121 sentences....
gpspassion Posted - 03 nov. 2008 : 19:47:29
Sounds good, go ahead !
adonix Posted - 11 mai 2008 : 01:49:22
Helle everyone, i need your help.

I'm trying to create a virtual TMC receiver for my Eten X500 using it's radio module.

Right now, i'm able to receive RDS packets and identify TMC messages. My software will interface with iGO using the Royaltek protocol.

Till now, i managed to send the following sentences to iGO:
$RTTMC,1,e213,1540,00e2,0080*4B : RDS/TMC message
$RTRDS,091.7,0,0,2,1,1,1,000,255,5,0,50*63 : Frequency identifier

iGO detects the vitualTMC, it also gives the channel name and display some RDS text if available. As for TMC, it writes "Test", then "TMC present" then "TMC status N/A" and it cycles these messages.

i noticed that iGO send sentences to the TMC hardware:
$PSRF121,1*38
$PSRF122,87.7*1C

i guess that these are tuning signals.

What i need is a log of an Royaltek receiver in order to reverse engineer the protocol. Or, informations on the protocol.

I dunno if Jose-Ramon have some information that helps me.

Thank you very much
Jose-Ramon Posted - 03 mars 2008 : 10:28:46
quote:
Thanks to Jose-Ramon for DecoRDS




Hello everybody, I am the creator of the DecoRDS. Let me answer some questions that I have seen in this thread:

1) No manufacturer publishes its communications protocol.

2) The information that I am going to make here, is the result of 'reverse engineer' ... therefore, may contain errors.

3) The GNS protocol, inserted information in binary RDS within chains NMEA GPS (ASCII). The indicator of the beginning and end of the RDS frame, is the character '?' CHR(&h3F)

4) Some receivers GNS must starting to begin insert information RDS within chains NMEA GPS ... others need to receive this information on a regular time (RDS-ON every 3"). Otherwise, non inserting the information RDS.

RDS-ON > CHR(&hFF) + CHR(&h56) + CHR(&h78) + CHR(&h78) + CHR(&h56)
RDS-OFF > CHR(&hFF) + CHR(&h53) + CHR(&h78)+ CHR(&h78) + CHR(&h53)

5) This is the way to tune the RDS receiver, using a GNS receiver:



6) The DecoRDS, detects and operates automatically with 5 different communication protocols.

7) The RoyalTek protocol inserted RDS using commands NOT included in the NMEA standard ($ RTTMC) ... but this makes it compatible with any software GPS, as it never breaks the frames NMEA GPS. This is an example, with the information sent by RDS RoyalTek GPS:

$RTTMC,1,e213,1540,00e2,0080*4B
$RTTMC,8,e213,8543,8873,1458*1B
$RTTMC,0,e213,054f,395e,2020*18


8) The DecoRDS can reproduce files 'log', but these files must be created with a single protocol (one line for each RDS group):

RDS: 16 hexadecimal characters (0 ... F) formatted text
ERROR: 1 character hexadecimal (0 ... F) formatted text to the error control (0 = 0% error / F = 100% error)
CR: 2 characters end line = CHR(&h0D) + CHR (&h0A)

Example, with RoyalTek protocol:

$ RTTMC,0,e213,054f,395e,2020*18
E213 054F 395E 2020 + ERROR (0 ... F) + CR

This is a file 'log', seen with a text editor:

E213E55D1800E2110
E213154000E208000
E213054F2F424D430
E2130548E32F44650
E21305492F426D6F0
E213255C6F7220650



More information here:

http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=92857
http://forum.pocketnavigation.de/thread.php?threadid=1061162&threadview=0&hilight=&hilightuser=0&page=2

camomille Posted - 27 févr. 2008 : 19:37:01
Hello,

My contribution :

Flux exchange data between "DecoRDS" on x50v and GNS5843 connected with serial port(rxd/txd) .

Scan frequency 87,6 Mhz by step 0,1 Mhz and search on 94,1/94,2/94,3/94,4 (RDS without TMC) and stop on 97,1 Mhz (with TMC).

Log asc in HTML for color
http://gardemanger.perso.cegetel.net/TMC/log_asc.htm
Log Hexa in HTML for color
http://gardemanger.perso.cegetel.net/TMC/log_hex.htm
Log asc in TXT for modify
http://gardemanger.perso.cegetel.net/TMC/Scan_DecoRDS_asc.txt
Log hex in TXT for modify
http://gardemanger.perso.cegetel.net/TMC/Scan_DecoRDS_hex.txt

Short script UltraEdit32 for extract codes RDS with file *_hex.txt :
var msg="";
var rds="";
var targetStr = UltraEdit.document[0];
targetStr.findReplace.regExp = true;
while (targetStr.findReplace.find("(3F.{25}3F|FF.*$)"))
{msg=targetStr.selection;
if (msg.substr(0,2)=="3F"){msg=msg.substring(3,27)+" <<<GNS";}
else {msg=msg+" >>GNS";}
rds=rds+msg+"\r\n";}
UltraEdit.newFile();
UltraEdit.activeDocument.write(rds);






Thanks to Jose-Ramon for DecoRDS
http://foro.todopocketpc.com/showthread.php?t=131911
http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=92857
VolkerSchulz Posted - 06 oct. 2007 : 15:12:08
Seems to work!

Sending a tuning request to the GPS receiver twice(!) turns on GNS 2.0 and makes the receiver sending both, NMEA and RDS/TMC data.

I do not have a RDS decoder yet, but the receiver starts sending those 10 byte blocks (probably 8 bytes RDS data + the '?' encapsulation).

Starting with either 0x3F or 0xFF seems to work fine.

So:

0x3F 0x46 0x7A 0x78 0x46 0x0D 0x0A 0x3F 0x46 0x7A 0x78 0x46 0x0D 0x0A
turns on GNS 2.0 support and tunes to 99.7 MHz

0x3F 0x46 0x00 0x78 0x46 0x0D 0x0A 0x3F 0x46 0x00 0x78 0x46 0x0D 0x0A
turns off GNS 2.0 support and switches back to NMEA 2.0 only.

Find a HEX to MHz conversion table here: http://www.capuzza.com/GNS/HEX2MHz.txt
VolkerSchulz Posted - 06 oct. 2007 : 13:57:43
Thanks, m.g., I'll send you a PN over there.

I didn't receive an answer to my inquiry from GNS but I did some research (also checked out what 'bill_gehts?' wrote) and I logged some communication data between the GPS receiver and Destinator PN navigation software.

Here's what I got so far:

-After starting the GPS receiver it sends out raw NMEA data with no RDS (TMC) included.

-After starting Destinator it 'initializes' the GPS receiver with some sort of command string to make it send out RDS data.

-Maybe it doesn't even 'initialize' but just tunes the receiver to a certain FM frequency.

-DavBouBou found out that the original app from GNS writes 5 bytes to the COM port (0xff,0x46,0x00,0x78,0x46). 'bill_gehts?' mentioned in another forum that this is the 'tuning comand', which should work as follows:

0xFF 0x46 ?? 0x78 0x46

?? = frequency:
00 = off
...
75: 99,2 MHz
76: 99,3 MHz
...
95: 102,4 MHz

-In my communication logs I've found the following:

(DST=Destinator, GPS=GPS receiver)
1:DST: 0x3F 0x56 0x78 0x78 0x56 0x0D 0x0A
2:GPS: 0x0A 0x0D 0x0A
3:DST: 0x3F 0x56 0x78 0x78 0x56 0x0D 0x0A
4:GPS: 0x3F 0x00 0x00 0x56 0x06 0x07 0x30 0x08 0x03 0x3F 0x0F 0x0A
5:DST: 0x3F 0x46 0x7A 0x78 0x46 0x3F 0x46 0x7A 0x78 0x46 0x0D 0x0A
6:GPS: <two NMEA sentences>
7:DST: 0x3F 0x46 0x7A 0x78 0x46 0x0D 0x0A

Line 1: Some sort of init? Also note the CR LF at the end.
Line 2: Answer?!? LF CR LF?
Line 3: Same as line 1.
Line 4: Looks like the first RDS block, encapsulated by '?'.
Line 5: Two(?) tuning requests with CR LF after the last one.
Line 6: NMEA sentence
Line 7: One tuning request with CR LF

m.g Posted - 06 oct. 2007 : 00:42:03
Splitter app: I read the original file byte after byte with some counter and switch output between the two out-files when '?' is met as delimiter of a rds-group.

The app for data-analyzis is a little more complicated, it is mine also. The image shows only partial information of the csv-file generated.

Communicate with the GPS receiver: Maybe just contact GNS and ask them kindly if they are willing to provide you this information. Otherwise you will need to log the communication data (in both directions) and analyze. Also search the posts from user 'bill_gehts?' on pocketnavigation.de...

For contact - if you prefer private communication, please pm me either on pocketnavigation.de or on navifriends.de, I will probably be back by Monday.

Sorry, this reply is rather short, but it is late in good old Europe... ;-)

m.g
VolkerSchulz Posted - 05 oct. 2007 : 01:30:21
Awesome! Splitting works perfectly and 'ALERT-C' may point me to the right direction. Would be glad to receive any additional information.

Which app did you use to display the extracted TMC data?

Did you write the spliter app? If so, is it as straightforward as I think it is:
- Find first '?'
- Extract 8 bytes from first position after '?'
- Delete 10 bytes from first '?' (data bytes + both '?')
- Start over

Do you know how to 'communicate' with the GPS receiver? Means:
- How to switch to TMC mode?
- How to tune manually?
- How to seek a station automatically?
- How to read information about current station (RDS)?

Can I contact you by instant messenger or email?
m.g Posted - 05 oct. 2007 : 00:42:01
You can use splitLog to separate gps data from tmc data. As for the ISO: look for ALERT-C, this should help to find the correct iso-specs.
Here is (partially) what I extracted from your file:

regards,
m.g

VolkerSchulz Posted - 04 oct. 2007 : 23:39:11
Hey guys!

Any progress in working with the GNS 2.0 protocol? I've bought a GNS 5843 (Bluetooth) just today and am still trying to figure out the TMC thing.

It works fine with my navigation software (Destinator PN) on my smartphone. I figured out that the GPS receiver sends standard NMEA only until TMC is activated (by some sort of command), which happens after my navigation software is started.

BeamRider: Which ISO specifications did you use to decode?

Find a first data log here:http://www.capuzza.com/nmea/. First with no TMC messages, then with TMC activated.

If somebody has useful information about GNS 2.0 or decoding the 8 byte messages, please let me know. Will be glad to upload more data logs if neccessary.

Cheers,
Volker
davboubou Posted - 26 juil. 2007 : 18:06:30
Does someone finally got some information on the GNS protocol and how to initialize a GNS TrafficBox?

Disassembling their GpsRdsRun_PC.exe, I found out that it writes 5 bytes(0xff,0x46,0x00,0x78,0x46) on the COM port, but it didn't work for me.

Thanks for any information.
PitaGyros Posted - 14 juin 2006 : 12:36:46
quote:
Originally posted by BeamRider

Thanks a lot, if the modular is GNS compatible then you'll see something like:
$GPGSS.........?xxxxxxxx?......
where xxxxxxxx is the 8 byte RDS group. The position inside the NMEA string isn't fixed, that's why you have to configure the 98xx in NMEA mode to make it work with non TMC software.



Hi!

I wanted to ask if someone could post a NMEA dump in the forum. I am especially interested in the GPGSS messages.

Thank you very much!
PitaGyros
admin_0 Posted - 27 mars 2006 : 19:19:06
quote:
Originally posted by CarPC

Does anyone have any s/w or information on the GNS 2.0 protocol which would help me do this?


Did you succeed in finding the GNS protocol online ??
mullions Posted - 16 août 2005 : 11:57:52
Hello,
to get the GNS protocol, you need to buy their SDK...or speak German.
gpspassion Posted - 21 juin 2005 : 09:55:32
I don't think GNS have released details on how it works. I haven't seen any tools so far that could decode it, only navigation software that uses it, like Navigon, Alturion or Destinator.

_________________________________________________________________________
Discounts and Assistance/Réductions et Assistance (Club GpsPasSion) / Où commencer?
CarPC Posted - 20 juin 2005 : 12:58:13
I have just bought a GNS 9830 GPS/TMC receiver. This came with no s/w to tune the radio so I cannot see any TMC messages. Does anyone have any s/w or information on the GNS 2.0 protocol which would help me do this? I can write my own code if necessary, but first I have to know what messages the 9830 expects.
BeamRider Posted - 31 oct. 2004 : 09:46:30
I've used GPGSS string as an example only: the RDS data is mixed with NMEA in every string (sorry, I don't know very well the NMEA strings meanings).
Is possible that modular sends RDS data only in Sirf mode? That behavior can explain why modular can be logged with conventional GPS software while GNS not.
I've got informations only for GNS units so please can you try with 98xx if/when you're able to?
Many thanks
gpspassion Posted - 30 oct. 2004 : 15:13:28
Ok, I logged the Modular GPS with VisualGPS CE in Nmea mode of course and I'm only getting the standard messages, sorry. Not sure how one would go about gettng these special GPGSS messages?

___________________________________________
Discounts and Assistance/Réductions et Assistance (Club GpsPasSion)
Best "GPS" PocketPC/Choisir un PDA ou un Kit "GPS" / Où commencer?
BeamRider Posted - 28 oct. 2004 : 17:44:29
Thanks a lot, if the modular is GNS compatible then you'll see something like:
$GPGSS.........?xxxxxxxx?......
where xxxxxxxx is the 8 byte RDS group. The position inside the NMEA string isn't fixed, that's why you have to configure the 98xx in NMEA mode to make it work with non TMC software.
My hardware needs only a free serial port connected to an RDS demodulator. RDS data stream is synchronous so I don't use RX line of the com port but a sort of interrupt driven logic. Synchronisation and error control/correction is described in ISO documentation.
I'm glad you're interested in my project, you'll surely receive it ASAP.

gpspassion Posted - 28 oct. 2004 : 17:36:32
I get it, very interesting indeed! I'm on a trip right now and only have the Modular GPS with me, I'll log to see if there are any odd messages. If that doesn't work I can log data from the 9830 nextnweek. GPSGate does ask you to connect in NMEA doesn't it, unless there's an option I've missed?
Also how do you get the data from your hardware into the PC/PocketPC ?
Feel free to pass on your .exe when you're ready ;-)
BeamRider Posted - 28 oct. 2004 : 17:19:31
Let's go deeper on it
Let's suppose that you have a normal GPS and you want to use it with your TMC enabled navigator software (Navigon, Alturion, D3 PRO, ecc..). Then my project get GPS data from the receiver and RDS data from a small unit I've built around an USB FM radio. The code creates a virtual com port that emulates the behaviour of the GNS 98xx unit feeding the navigator with GPS and TMC data. That's all for emulation.
For the log you can try a software GPS splitter like GPSGate (I think it can write a log while sending data to the software) resolving your initialisation issue. The resulting file is binary (RDS group are binary).
The TMC databases are free of charge and usually given by national traffic bureaus. The good thing is that my code is binary compatible with Tricksy databases. I can send you an executable version of my code in a few days (just give me the time to clean some parts). It's ugly and unoptimized but runs on any Windows PC.
gpspassion Posted - 28 oct. 2004 : 17:00:16
Not sure I'm following the emulation part? If you have something to test on a PC, I'll be glad to help. On the log, problem is that with the 9810/30 you need to switch them in GPS" mode for them to work with a normal GPS program that can log. The Modular is different, I'll check a log. You're going to need the TMC tables too, can they be bought?
BeamRider Posted - 28 oct. 2004 : 16:46:28
Hi,
I'm from Genova(Italy).
A NMEA log is exactly what I'm looking for but be sure to tune to a TMC station please(obivious but imperative). In the log file you'll see some strange packets mixed with NMEA strings. These are RDS groups, TMC messages are coded inside a specific RDS group.
As I said, I'm able to decode them but not sure if my code supports the multigroup TMC message type. I implemented the decoder using the ISO specifications so I'm quite sure it'll work.
My project goal is to give textual TMC messages in a window where an GPS/RDS unit is used as emulating the unit using my own hardware and a conventionsal GPS. Actually the first phase is complete (awaiting to test with your log ), the second is in development. The platform I'm using is Windows but the code is portable to PPC without too much work.
gpspassion Posted - 28 oct. 2004 : 15:50:59
Interesting idea! Where are you located? As for producing a log I'd be glad to help, but I don't know how a full log can be created, other than a standard NMEA log?

GpsPasSion Forums © 2002-2014_GpsPasSion/Manzanite Go To Top Of Page
This page was generated in 1,09 seconds. Powered By: Snitz Forums 2000 Version 3.4.05