id	summary	reporter	owner	description	type	status	priority	component	version	resolution	keywords	cc
122	BNC only retrieves correction information in Auto NMEA if port is opened by another application	mikko.seppala@…	mikko.seppala@…	"HW/SW: u-blox F9P (usb virtual comport) and commercial VRS correction service requiring NMEA input.

Using VRS service with NMEA set to Auto in Serial output does not seem to send data to serviceprovider unless the serial port is opened by another application.
See video:
https://www.youtube.com/watch?v=yGmjv8ZyZYg

Datarate from provider is under 0.1kB/s when serial port is not opened and RTCM decoder shows no data, GGA sentence confirms no RTK or DGPS is achieved. Once port is opened, datarate increases to over 0.6kB/s and RTCM decoder shows data flowing and GGA sentence shows instant RTK Fix. Once the program reading the port is closed, datarate decreases and age of differential in GGA sentence keeps increasing as no correction input is received.

If the serial port is opened by an application before BNC is started, data from the VRS provider does not flow at all as NMEA strings are not passed to BNC and the service provider.


When Manual GNGGA is selected instead of Auto, the logged GGA sentences show that RTK Float is achieved just by starting BNC, but due to most likely wrong NMEA string sent to VRS service, the Float rarely goes to Fix and is not as accurate as it could be.


Tested on BNC 2.12.12-ubuntu-shared from downloads page and SVN r8910 (with one line commented out so it compiles)."	defect	closed	normal	BNC		fixed	vrs