Novatel SUPERSTAR II OM-20000077 - Manual (Page 37)

Message Formats Chapter 5
SUPERSTAR II User Manual Rev 3 37
Type 9 messages contain the following information for a group of three satellites in view at the base station:
• Scale factor
• User Differential Range Error
• Satellite ID
• Pseudorange correction
• Range-rate correction
• Issue of Data (IOD)
5.2 NMEA Format Data Messages
The NMEA log structures follow format standards as adopted by the National Marine Electronics Association.
The reference document used is "Standard For Interfacing Marine Electronic Devices NMEA 0183 Version
2.00". For further information, see Appendix D, Standards/References on Page 62. The following table contains
excerpts from Table 6 of the NMEA Standard which defines the variables for the NMEA messages. The actual
format for each parameter is indicated after its description.
Field Type Symbol Definition
Special Format Fields
Status A Single character field:
A = Yes, Data Valid, Warning Flag Clear
V = No, Data Invalid, Warning Flag Set
Latitude llll.ll Fixed/Variable length field:
degrees|minutes.decimal - 2 fixed digits of degrees, 2 fixed digits of minutes and
a variable number of digits for decimal-fraction of minutes. Leading zeros always
included for degrees and minutes to maintain fixed length. The decimal point and
associated decimal-fraction are optional if full resolution is not required.
Longitude yyyyy.yy Fixed/Variable length field:
degrees|minutes.decimal - 3 fixed digits of degrees, 2 fixed digits of minutes and
a variable number of digits for decimal-fraction of minutes. Leading zeros always
included for degrees and minutes to maintain fixed length. The decimal point and
associated decimal-fraction are optional if full resolution is not required
Time hhmmss.ss Fixed/Variable length field:
hours|minutes|seconds.decimal - 2 fixed digits of hours, 2 fixed digits of minutes,
2 fixed digits of seconds and variable number of digits for decimal-fraction of
seconds. Leading zeros always included for hours, minutes and seconds to
maintain fixed length. The decimal point and associated decimal-fraction are
optional if full resolution is not required.
Defined field Some fields are specified to contain pre-defined constants, most often alpha
characters. Such a field is indicated in this standard by the presence of one or
more valid characters. Excluded from the list of allowable characters are the
following which are used to indicate field types within this standard:
"A", "a", "c", "hh", "hhmmss.ss", "llll.ll", "x", "yyyyy.yy"
Numeric Value Fields
Variable
numbers x.x Variable length integer or floating numeric field. Optional leading and trailing
zeros. The decimal point and associated decimal-fraction are optional if full
resolution is not required (example: 73.10 = 73.1 = 073.1 = 73)
Fixed HEX hh___ Fixed length HEX numbers only, MSB on the left
Information Fields
Variable text c--c Variable length valid character field.
Fixed alpha aa___ Fixed length field of uppercase or lowercase alpha characters
Fixed number xx___ Fixed length field of numeric characters
Fixed text cc___ Fixed length field of valid characters
NOTES:
1. Spaces may only be used in variable text fields.
2. A negative sign "-" (HEX 2D) is the first character in a Field if the value is negative. The sign is omitted if value is positive.
3. All data fields are delimited by a comma (,).
4. Null fields are indicated by no data between two commas (,,). Null fields indicate invalid or no data available.
5. The NMEA Standard requires that message lengths be limited to 82 characters.