GpsDiffuser - Real time and delayed time GPS localization data diffusion

V 5.0.1

Documentation


Table of contents

  1. Real time Navigation mode
    1. Real time mode behaviour
    2. Launching navigation
      1. Supported GPS receiver models
      2. Selecting port and speed
      3. Protocol
      4. Settings to be done on GPS receiver
    3. Navigation log
    4. Automatic launch of navigation when starting
  2. Replay Mode
    1. Loading files
    2. Replay modes : time and speed
    3. Dashboard
    4. File processing
  3. Displayed information
    1. Replay information
    2. NMEA information
  4. Diffusion
    1. Diffused NMEA information
    2. Diffusion addresses
  5. Configuration file
  6. Command line parameters
  7. Menus
  8. Appendix A : Supported formats

GpsDiffuser is a program that diffuses real time or replayed GPS data.
This diffusion is done by transmission of sentences at format NMEA 0183 on UDP ports.
Diffused data come either from a GPS receiver or source issuing on UDP in real time navigation mode, either from a replayed file.
In case of replay, position and speed settings are modifiable.
GpsDiffuser is at least compatible with itself, GeoVisu and GpsGate.

GpsDiffuser is available for Windows 2000/XP/2003/Vista/Seven. This program is free of charge.

I. Real time Navigation mode

Real time mode is the case of receipt of NMEA sentences on a port. Possible ports are serial (COMx), USB or UDP. Activation is done using menu Gps/Navigation.

1. Real time mode behaviour

In real time mode, dashboard buttons are inactive.
Information about NMEA sentences contents are displayed in the lower part of the screen.
Whatever the choosen port is, navigation starts even if no GPS receiver is connected on the port. However, display of current navigation position will happen only when receiving data.

2. Launching navigation

If Navigation option is already checked, Navigation menu stops navigation. Otherwise, it displays navigation screen.

a. Supported GPS receiver models

Navigation (display current position) is possible with all serial GPS receivers supporting protocol NMEA0183, and with Garmin USB GPS receivers (Garmin PVT protocol). Garmin PVT protocol on serial (COM) port is not supported.

GpsDiffuser has been tested with the following models :

PVT navigation Garmin Quest, Garmin GPS 18
NMEA navigation Garmin GPS II Plus, Magellan Sportrak, Haicom Hi-204 III, Emtac Trine, GlobalSat DG-100, Lowrance GlobalMap 100, Royaltek BlueGps RBT-3000, Evermore GT-600, eBontek eGPS-597, iBlue 747.

b. Selecting port and speed

Proposed ports are :

For every USB GPS receiver whose driver creates a virtual COM port, or for a software as GPSGate emulating a virtual COM port, you must choose "COM port".

Only one GPS receiver or port can be selected at a time.

In all cases, you can start navigation even when GPS receiver is not connected or port does not exist.

c. Protocol

Protocol is automatically set to Garmin PVT for Garmin USB, and to NMEA in all other cases.
Other protocols are not supported yet.

d. Settings to be done on GPS receiver

GPS model Settings to be doneRemarks
Serial Garmin Please select the right protocol : NMEA/NMEA 4800b.
USB GarminThere is nothing to set. GpsDiffuser starts PVT emission.
MagellanSpeed must be the same as the one selected in screen. GpsDiffuser automatically starts NMEA emission.
Royaltek RGM-3800 Speed selected in screen must be 115200b. GpsDiffuser automatically starts NMEA emission.
Royaltek RBT-2300, RCD-1100 Speed selected in screen must be 57600b GpsDiffuser automatically starts NMEA emission.
Globalsat DG-1001. Speed selected in screen must be 115200b.
2. It seems that, for Globalsat DG-100, navigation is no longer possible after downloading log ; you have to switch the GPS receiver off and then on.
GpsDiffuser automatically starts NMEA emission.
Other GPS receiversNMEA emission must be started by user (or by default).
Speed must be the same as the one selected in screen.

Attention : geodetic system information is generally not transmitted by standard NMEA protocol.
Non-Garmin GPS receivers must either be set to WGS84 system (recommanded), or be configured to issue NMEA sentence $GPDTM.

3. Navigation log

There is an option to log sentences received from GPS receiver into a NMEA file.
This option can be switched on and off either using "Log navigation" menu, either by the same name checkbox in navigation screen.

Log files are stored in log directory (see configuration file). Default log directory can be opened using GpsDiffuser Start menu.

In case of NMEA GPS receiver, these are raw sentences received from GPS receiver ; Garmin PVT protocol is converted to NMEA sentences, some of them being Garmin proprietary.

It is not possible to log data received on UDP port.

4. Automatic launch of navigation when starting

When GpsDiffuser is launched using command line, or by a shortcut, it is possible to start automatically real time navigation, with or without log.
To do this, you have to give an argument among the following :

Examples :

"C:\program files\geovisu suite\gpsdiffuser.exe" -NAVIGLOG COM3 -NAVIGPORTSPEED 9600
"C:\program files\geovisu suite\gpsdiffuser.exe" -NAVIG UDP7551

GPS receiver does not need to be connected, neither port needs to exist, before launching GpsDiffuser.
As soon as GpsDiffuser can open port and receives data, it will diffuse them.

It is therefore possible to launch automatically navigation (on a given port) when starting the computer, by placing such a shortcut in the "Startup" menu of Windows.

II. Replay mode

Replay mode is the case of processing a file. When a file is loaded (menu File/Open or drag&drop), dashboard is active and provide replay starting. Replay starting is done by clicking Forward or Backward button.

1. Data loading

"Open" menu is used to select a file for loading. Only files with an extension corresponding to a format that GpsDiffuser can process are proposed.

Another way is to drag and drop either one or several files.

You can give file names to GpsDiffuser using the command line or a shortcut. You can put in the command line file names (cf. Command line parameters).

GpsDiffuser can load files even when the extension doesn't correspond to the format of the file. GpsDiffuser automatically recognizes file format.

GpsDiffuser does not read compressed files (Gzip and ZIP) directly.

2. Replay modes : time and speed

When replaying, you can change time or speed factor. Information are displayed in the lower part of the screen. Board buttons are described in next section.

Replay can be done in two modes : "Replay time" and "Replay speed".

3. Dashboard

Dashboard is active when at least one file has been loaded and that «real time navigation» mode is not active.
Various fields of the dashboard are :

File The corresponding combo box contains all files that have been loaded.
You can change current file when replay and mode «real time navigation» are not active.
Changing of file comes with the display of the context (current position, mode, ...) of this file.
When loading, mode is «Replay time» with a factor of 1.
Time factor Time factor can be modified everywhen.
To do this, you have to either enter a value in the input box, either move cursor.
In both cases, the value displayed on the right remains red as long as it has not been validated.
Validation is done by clicking button.
If the modification is done while replaying, GpsDiffuser simulates a tracklog change. This tracklog change information is taken into account by GeoVisu.
Validation also sets the mode to «Replay time». In this mode, the trip is done at a multiple of the real speed.
Speed Speed can be modified everywhen.
To do that, you have to either enter a value in the input box, either move cursor.
In both cases, the value displayed on the right remains red as long as it has not been validated.
Validation is done by clicking button.
Validation also sets the mode to «Replay speed».
If the modification is done while replaying, GpsDiffuser simulates a tracklog change. This tracklog change information is taken into account by GeoVisu.
Position Position among tracklog is symbolized by the cursor.
This cursor moves while replaying.
When no replay, neither navigation, is active, you can move cursor to move along the tracklog. Such a move comes with transmission of GPS positions on UDP ports.
Buttons Buttons allow you to manage replay. These buttons are :
  • Infinite loop
  • Reverse play
  • Pause
  • Play
  • Stop (Pause + reset at beginning)

4. File processing

GpsDiffuser can replay files other than raw NMEA files.
GpsDiffuser converts theses files to NMEA format, and recreates if necessary calculated positions. The aim is to diffuse NMEA sentences with a sufficient frequency to allow a real animation.

III. Displayed information

1. Replay information

Mode, Factor, Distance km and Duration concern replay.
Distance and duration are those from beginning of track to current position. They are calculated information.

2. NMEA information

Information Longitude, Latitude, Altitude, Speed, Direction, Number of satellites in vue and used, and NMEA sentences are displayed in every mode when they are available.
They are extracted from raw or calculated NMEA sentences.

Speed is calculated if it is not available among input data.

IV. Diffusion

1. Diffused NMEA information

When you click Play button (forward or backwark) (resp. Pause or Stop), GpsDiffuser issues in addition proprietary sentence $PGVUT,START (resp. $PGVUT,STOP) which indicates beginning (resp. stop) of navigation.

2. Diffusion addresses

Diffusion is activated by default. It is done to all recipients declared in «Selected» area of «Diffusion addresses» screen.
To de-activate diffusion you have to use menu Diffusion/Diffusion.

Recipient adresses management is done using «Diffusion addresses» screen, which is available from menu Diffusion/Diffusion addresses.
A recipient address consists of an IP address or web/DNS address, and of an UDP port number.
Usual UDP port numbers for GpsDiffuser are values from 7551 to 7559.

By default, GpsDiffuser diffuses to ports 7551 and 7552 on the local machine (localhost).

V. Configuration File

Configuration File «gpsdiffuser.cfg» allows you to define some GpsDiffuser parameters.

Parameter SyntaxUse
GpsDiffuser language
(English or French)
LANG ENGLISH
(or : LANG FRANCAIS )
This parameter allows you to change GpsDiffuser language (English or French).
By default, GpsDiffuser takes into account operating system language.
Real time navigation log directory LOG_DIR c:\nmea This parameter allows you to modify navigation log directory.
ACTIVE_NMEA_UDP_DIFFUSE_ADRx ACTIVE_NMEA_UDP_DIFFUSE_ADR1 mycomputer 7553
ACTIVE_NMEA_UDP_DIFFUSE_ADR1 192.168.1.45 7555
ACTIVE_NMEA_UDP_DIFFUSE_ADR1 computer.domain.com 7552
This parameter allows you to add recipients selected for diffusion. x can take values from 1 à 9.
The addition of the name of a computer that doesn't exist on the network nor on the web results in a loss of time at the start of GpsDiffuser. This loss of time is due to the DNS search of the name of the computer.
INACTIVE_NMEA_UDP_DIFFUSE_ADRx INACTIVE_NMEA_UDP_DIFFUSE_ADR1 mycomputer 7553
INACTIVE_NMEA_UDP_DIFFUSE_ADR1 192.168.1.45 7555
INACTIVE_NMEA_UDP_DIFFUSE_ADR1 computer.domain.com 7552
This parameter allows you to add recipients non-selected for diffusion. x can take values from 1 à 9.
The addition of the name of a computer that doesn't exist on the network nor on the web results in a loss of time at the start of GpsDiffuser. This loss of time is due to the DNS search of the name of the computer.

gpsdiffuser.cfg file is available from GpsDiffuser Start menu. It can by modified using a text editor.
Lines beginning with # are comments.
An example file (gpsdiffuser_exemple.cfg) is provided in GpsDiffuser installation directory.

VI. Command line parameters

When run using command line or shortcut, GpsDiffuser can have the following parameters :

Parameter SyntaxUse
Load file-LOAD "file_name" Use this parameter to load a file.
The name cannot be a web address.
This option does not allow to load of a directory.
This parameter may be used as many times as there are files to load.
Example : -LOAD "c:/directory/file1.gvt" -LOAD "D:/file.nmea"
Loop replay file -PLAY "file_name" Use this parameter to loop replay a file.
The name cannot be a web address.
This option does not allow loading of a directory.
Example : -PLAY "c:/directory/file1.gvt"
Navigation automatic launch -NAVIG port_name
-NAVIGLOG port_name
-NAVIG launches navigation on selected port.
-NAVILOG launches navigation and log on selected port (except UDP).
Port name syntax is : COMx UDPx USB where x is the port number.
Example : -NAVIG UDP7551
(cf. paragraph I.4).
COM port speed -NAVIGPORTSPEED speed Use this parameter to set COM port speed in baud. It is an integer value.
This parameter is mandatory for COM ports when using -NAVIG COMx or -NAVILOG COMx.
This value must be equal to the GPS issue speed (cf. paragraph I.2.b).
Example : -NAVIGLOG COM3 -NAVIGPORTSPEED 4800
Log directory -LOG_DIR "directory" Use this parameter to set log directory.
Example : -LOG_DIR "c:/nmea"
Configuration file path -CONFIG_FILE "file_name" Use this parameter to set absolute path of the configuration file, if different from the default one.
Example : -CONFIG_FILE "G:/gpsdiffuser/gpsdiffuser2.cfg"

If the first string of the command line is a file name, it is interpreted as a loop replay file parameter.
Example : "C:\program files\geovisu suite\gpsdiffuser.exe" "c:\file1.gvt" means "C:\program files\geovisu suite\gpsdiffuser.exe" -PLAY "c:\file1.gvt"

VII. Menus

  1. File
    1. Open
      It is used to load a file containing GPS data.
    2. Quit
      Exits the application.
  2. GPS
    1. Navigation (current position)
      This is used to switch on and off real time navigation.
      When activating, this menu shows navigation screen.
      Function can be switched on before or after launching communication on GPS receiver or on UDP, it will take effect as soon as it receives navigation data.
    2. Log navigation
      This is used to record into a file in NMEA format, data sent from GPS receiver during navigation.
      This functionality is not available for data received on UDP port.
      This function can be switched on before or after starting navigation, but of course it will work only when navigating.
  3. Diffusion
    1. Diffusion addresses
      This shows Diffusion addresses screen.
    2. Diffusion
      Activates or de-activates diffusion towards ports specified in the &«Selected» list.
      This menu is checked by default.
  4. About
    This displays version information.

Appendix A : Supported formats

  1. GPS
    Format DescriptionNotes
    GPXGPS eXchange Format  
    NMEARaw NMEA log  
    MapSendMagellan MapSend  
    GTM 211GPS TrackMaker (binary)  
    GTM 212GPS TrackMaker text  
    OziExplorer  Waypoint, tracklog, route, event eand point file
    MagellanRaw Magellan log (NMEA format)  
    USRLowrance USR  
    TK1, TK2, TK3Wintec GeoVisu does not read TK4 waypoint format from WGS1000/GTender.
    Garmin XML Garmin Training Center and Forerunner Logbook (HST, CRS)  
    PCX5Garmin PCX5  
    MapShowAlan Map, Holux Tracklogs and waypoints (WPO, WPR, TRL)
    Emtac Trine Raw Emtac Trine log (NMEA format)  
    GVT
    GVW
    GVR
    GeoVisu Tracklogs
    GeoVisu Waypoints
    GeoVisu Routes
    GeoVisu uses its own data format to store data downloaded from Garmin and Navilink GPS receivers. Coordinate system is WGS84.
    These are ASCII files. See format in GeoVisu documentation.
    GVN GeoVisu Navigation GeoVisu uses its own data format to store data downloaded from GlobalSat, Wintec, Skytraq, Navilink GPS loggers. Coordinate system is WGS84.
    These are ASCII files. See format in GeoVisu documentation.
    RTKT Binary Royaltek log prefixed by NMEA sentences.  
    MTKT Binary Mediatek (MTK) log prefixed by NMEA sentences.  


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