Syncbox can accept data transfer from the user simulation system via Ethernet or RS232. The data format in each case uses the ASCII NMEA format for $GPGGA.
$GPGGA_HHMMSS.SS_DDMM.MMMMM_K_DDDMM.MMMMM_L_N_QQ_PP.P_AAAA.AA_M_±XX.XX_M, SSS_RRRR*CC<CR><LF>
Ethernet/LAN communication uses UDP protocol. Port number and IP address/DHCP are configurable via the SD card configuration file.
RS232 data input can be configured via the SD card file.
You can configure the network interface and serial interface for position input via a text file copied to the microSD card. The file must be named 'config.txt'. A typical configuration file will look like the following examples when opened in a text editor such as Windows Notepad:
Note: The case of the commands does not matter, they can be upper, lower or a mixture of both.
This is the UDP port number over which the Syncbox will receive the NMEA trajectory information.
IP address of the SyncBox, if this complete line is left out, it will use DHCP instead.
Smoothing
This value is the amount of smoothing in samples that will be carried out on the input stream. Typically, this value should be 1 if the user NMEA data is supplied at 100 Hz.
The lower this number, the lower the latency of the system. A value of 1 runs at the native latency of SatGen which is ~100 ms. A value of 10 adds 100 ms, and a value of 100 adds 1 second. If the user has 100 Hz+ data, then a low number would be fine, 10 Hz requires a smoothing rate of at least 20, and 1 Hz at least 100.
This parameter will use the internal RTC (if a backup battery is wired in). Leaving this line out it will use the first time (UTC) received over Ethernet to start the clock.
If you set Log to equal ‘true’, the Syncbox will timestamp and log to the microSD card the incoming Ethernet packets and also log the output from the unit to SatGen. This can be run whilst in normal operations without causing problems with SatGen. However, to avoid filling the microSD card, it is recommended that this parameter is set to ‘false’ unless required.
Echo
If you set Echo to equal 'true’ the input from the Ethernet Port will echo over the USB serial input.
Note: this will stop SatGen from working as this uses the USB serial port. Set to 'false' for normal use.
If this statement exists and is ‘true’, user data will be taken from the RS232 input rather than the Ethernet UDP.