This format can...
This is the log format output by factory-installed Honda/Acura (Alpine) Navigation Systems in (at least) 2006 models and newer. (Though I've seen indirect data that says that Acura nav systems at least as far back as 2004 use it too)
This format is definitely known to work with the following model cars specifically:
|2006 Honda Civic Hybrid|
Logging may be enabled by simultaneously holding down the MAP/GUIDE, MENU, and CANCEL buttons for 3-5 seconds, then selecting "Functional Setup", "Log Data". A PCMCIA card must be inserted into the system (behind the Nav LCD) for logging to work. (The system can read MP3/WMA files on this card and will also write logs to it. Generally, a PCMCIA to CF or PCMCIA to SD adapter is used with a corresponding CF/SD card) With logging successfully set up, the system will create a directory named "VPlog" off the root of the card. Inside this directory, files will be created with names corresponding to the date and time of engine start, in GMT. (YYMMDD_HHMM.vpl)
The VPL format contains quite a bit of data, much of which remains undecoded. This format currently reads only lat/lon, altitude, speed, heading, date/time, visible sats, HDOP and VDOP.
Generally, the layout of the format seems similar to NMEA, with discrete sentences containing different fields of data, followed by a 1-byte XOR'd checksum. Some sentences are generated only once per engine start, others every few seconds, many every second, and a few on the order of five and in one case, up to twenty five times per second. All data in the file is written in ASCII; most of it simply as hexadecimal characters. Most fields are fixed width, though a few can be variable. (Those that are variable have a field count as the first field after their sentence identifier) Currently, only the '75'-sentence is processed (and only about 70% of it), though this provides all the data necessary for position information. Some fields in other sentences have been decoded, but they are not currently processed. Information on the data in these fields can be found in vpl.c.