01-07-2018, 07:44 PM
Colin
Most common GPS receivers output at least 5 data strings in NMEA format every second, sometimes more in a format native to the basic GPS receive engine. I am a little unsure why you would want to use an Arduino (of any flavour) to reprocess NMEA data to put it onto a USB port (a pseudo-COM port). Reprocessing will take critically important time when you are trying to get as close as possible to the true GPS incremental time change from one second to the next (within a few milliseconds). The faster the baud rate of the data from the GPS receiver to the PC, the lower the timing discrepancy. At a 56 Kbaud data rate, the error I measured was under 70mS in total.
All you really need to do is use a serial to USB adapter device to turn the serial TTL/CMOS levels from the receiver into USB-compatible signals - something like an FTDI FT232RL would do the job nicely. The Arduino Serial to USB adapter XC4464 module from Jaycar is not FTDI-based but has drivers available that work Win7-10 and will do the same job.
Above all, you still need to process the NMEA data in the PC to be able to set the clock, do grid square calcs etc. Oh wait, that's what my GPS2Time software already does from a raw data stream from a cheap-ex GPS receiver module with another cheap-ex serial/USB device in between - OR - buy a cheap-ex GPS receiver with a USB lead out of it...
Doug
Most common GPS receivers output at least 5 data strings in NMEA format every second, sometimes more in a format native to the basic GPS receive engine. I am a little unsure why you would want to use an Arduino (of any flavour) to reprocess NMEA data to put it onto a USB port (a pseudo-COM port). Reprocessing will take critically important time when you are trying to get as close as possible to the true GPS incremental time change from one second to the next (within a few milliseconds). The faster the baud rate of the data from the GPS receiver to the PC, the lower the timing discrepancy. At a 56 Kbaud data rate, the error I measured was under 70mS in total.
All you really need to do is use a serial to USB adapter device to turn the serial TTL/CMOS levels from the receiver into USB-compatible signals - something like an FTDI FT232RL would do the job nicely. The Arduino Serial to USB adapter XC4464 module from Jaycar is not FTDI-based but has drivers available that work Win7-10 and will do the same job.
Above all, you still need to process the NMEA data in the PC to be able to set the clock, do grid square calcs etc. Oh wait, that's what my GPS2Time software already does from a raw data stream from a cheap-ex GPS receiver module with another cheap-ex serial/USB device in between - OR - buy a cheap-ex GPS receiver with a USB lead out of it...
Doug
Doug VK4ADC @ QG62LG51
http://www.vk4adc.com
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http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.