the old mechanism wasted most of the input bytes, and chewed a lot of
CPU, making it impractical to do GPS detection for a GPS attached
after startup
The new code is async, and detects a GPS by looking for a fully formed
packet with the right checksum for each GPS type
if a UBlox is configured for NMEA only, with no UBX messages at all
then it would never trigger the GPS_AUTO detection. This adds a UBX
config message to the init strings that enables the NAV_SOL message
the parser was broken in several ways:
1) when it received an unknown message it didn't update the ck_a and ck_b fields, so it
thought the message had a bad checksum, which meant it got out of protocol sync
2) the read() method would return false if the last message from the GPS was of an unknown type.
So we relied on the last msg always being one that we understand and want
3) the parser considered any valid UBLOX message to be 'new data', whereas we only actually get
a new fix when we get box a new position and velned message
4) the total message size per update is more than 128 bytes, but the serial port was opened
with only a 128 byte buffer, so we got corruption regularly
Nuke AP_GPS_IMU, as nothing is using it anymore.
Simplify the handling of no GPS/no fix detection.
Fix prototypes for ::init and ::read.
Update AP_GPS_Auto and corresponding example, nearly ready for primetime.
Use uint8_t rather than byte.
Strip some _error() calls to save space. More could still go.
git-svn-id: https://arducopter.googlecode.com/svn/trunk@1246 f9c3cf11-9bcb-44bc-f272-b75c42450872
Note that this is currently disabled as changes need to be made to APM to support it.
Tested with MTK, u-blox and SiRF GPS'.
git-svn-id: https://arducopter.googlecode.com/svn/trunk@671 f9c3cf11-9bcb-44bc-f272-b75c42450872
Andrew Tridgell
Pat Hickey
rmackay9
James Goppert
deweibel@gmail.com
deweibel
DrZiplok@gmail.com
james.goppert
paulbmather@gmail.com
jasonshort