diff --git a/docs/application_layer.rst b/docs/application_layer.rst index 0ea3c0f..47295a3 100644 --- a/docs/application_layer.rst +++ b/docs/application_layer.rst @@ -78,12 +78,18 @@ GNSS Position Data stores the 112 bit META field as follows: * - Size, in bits - Format - Contents - * - 32 - - 32-bit fixed point degrees and decimal minutes (TBD) - - Latitude - * - 32 - - 32-bit fixed point degrees and decimal minutes (TBD) - - Longitude + * - 8 + - 8-bit signed integer + - Latitude - degrees, integer part (-90..+90, positive values for northern hemisphere) + * - 16 + - 16-bit unsigned integer + - Latitude - degrees, fractional part (eg. 0.5 -> 32,768) + * - 16 + - 16-bit signed integer + - Longitude - degrees, integer part (-180..+180, positive values for eastern hemisphere) + * - 16 + - 16-bit unsigned integer + - Longitude - degrees, fractional part (eg. 0.5 -> 32,768) * - 16 - unsigned integer - Altitude, in feet MSL. Stored +1500, so a stored value of 0 represents -1500 MSL. Subtract 1500 feet when parsing. @@ -92,8 +98,8 @@ GNSS Position Data stores the 112 bit META field as follows: - Course in degrees true North * - 10 - unsigned integer - - Speed in miles per hour. - * - 12 + - Speed in knots + * - 20 - Reserved values - Transmitter/Object description field