[gpsd-dev] problem with gpsmon for an oncore device

[Mick Durkin]

Hi Gents,

I noticed that I was getting suspicious "unhealthy" flags against 
certain SVs when using gpsmon with an Oncore device.

I checked the packet dump and all the SVs were showing good health, so I 
had a dig into the code of monitor_oncore.c. It looks as though the 
"health" variable is being read too "early" in the buffer. The "az" 
variable which precedes it is a 16 bit value, so the offset between them 
should be 2 bytes, not one.

Here is my suggestion for a fix. The last line of the embedded diff 
wraps locally in my mailer as the original source line is over 80 
characters. I'm not sure how that will show up when it reaches you.

BR

Mick

=====================================

$ git diff -u
diff --git a/monitor_oncore.c b/monitor_oncore.c
index ed2d1dc..f5aec8d 100644
--- a/monitor_oncore.c
+++ b/monitor_oncore.c
@@ -326,7 +326,7 @@ static void oncore_update(void)
            doppl = (int)getbes16(buf, off + 1);
            el = (int)getub(buf, off + 3);
            az = (int)getbeu16(buf, off + 4);
-           health = (int)getub(buf, off + 5);
+           health = (int)getub(buf, off + 6);

            (void)wmove(Bbwin, (int)Bblines[i], 1);
            (void)wprintw(Bbwin, "%3d %3d %2d %5d %c%c", sv, az, el, 
doppl, (health & 0x02) ? 'U' : ' ',        /* unhealthy */