_sDMSPacket = string.Format(":000000 {0:0000}{1}{2:0000} {3:0000}\r\n", (int)Math.Floor(dHeave * 100 + 0.5), 'G', (int)Math.Floor(dRoll * _R2D * 100 + 0.5), (int)Math.Floor(dPitch * _R2D * 100 + 0.5));
Using the above, I get values like
:000000 -0021G0006 0281
:000000...