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ER2 Nav Data Recorder Data Format


The Nav data output format and time channel data format provided below were taken from the ER2 Investigator's Handbook.

4. NAVIGATION DATA RECORDER OUTPUT

4.1 RS 232 Navigation Data Output To Payload Areas

The data from all navigation data inputs is accumulated in a buffer for one second. The Data is processed and output to the RS232 data bus at 9600 Baud. This results in a delay of one second between the actual time the data is received and the time it is output on the RS232 data bus. The time is correct to one millisecond. The output format is as follows:

Parameter Units Output Format
Byte Size
 Source
Header, GPS Status 'SOH' [G/N] ASCII XX
2
 Inserted
UTC Time (GMT) days:hrs:min:sec ASCII XXX:XX:XX:XX
12
 GPS
Present Pos. Latitude DEGREES ASCII N/S XX.XXXXX
9
 INU
Present Pos. Longitude DEGREES  ASCII E/W XXX.XXXXX
10
 INU
True Heading DEGREES ASCII XXX.XX
6
 INU
Pitch Angle (up + ) DEGREES ASCII ±XX.XXXX 
8
 INU
Roll Angle (rt. + ) DEGREES ASCII ±XX.XXXX
8
 INU
Ground Speed METERS/Sec ASCII XXX.XX
6
 INU
Track Angle True DEGREES ASCII XXX.XX
6
 INU
Inertial Wind Speed METERS/Sec ASCII XX.X
4
 INU
Inertial Wind Direction  DEGREES ASCII XXX.X
5
 INU
Body Longit. Accl. G ASCII ±X.XXX
6
 INU
Body Lateral. Accl. G ASCII ±X.XXX
6
 INU
Body Normal Accl. G ASCII ±X.XXX
6
 INU
Track Angle Rate DEGREES/Sec ASCII ±XX.X
5
 INU
Pitch Rate DEGREES/Sec ASCII ±XX.X
5
 INU
Roll Rate DEGREES/Sec ASCII ±XX.X
5
 INU
Inertial Vertical Speed METERS/Sec ASCII ±XX.XX
6
 INU
GPS Altitude METERS ASCII XXXXX.X
7
 GPS
GPS Latitude DEGREES ASCII N/SXX.XXXXX
9
 GPS
GPS Longitude DEGREES ASCII E/WXXX.XXXXX
10
 GPS
Static Pressure * Millibar ASCII XXXX.XXX
8
 Analog
Total Pressure  Millibar  ASCII XXXX.XXX
8
 Analog
Differential Pressure  Millibar ASCII XX.XXX
6
 Analog
Total Temperature * Degree C ASCII ±XX.XX
6
 Analog
Static Temperature * Degree C ASCII ±XX.XX
6
 Derived
Barometric Altitude * Meters ASCII XXXXX.X
7
 Derived
Mach No * N/A ASCII X.XXX
5
 Derived
True Air Speed * METERS/Sec ASCII XXX.XX
6
 Derived
Wind Speed * METERS/Sec ASCII XX.X
4
 Derived
Wind Direction * DEGREES  ASCII XXX.X
5
 Derived
Sun Elevation  DEGREES ASCII ±XX.XX
6
 Derived
Sun Azimuth DEGREES ASCII XXX.XX
6 
 Derived
Analog Channels (12) Volts ASCII ±X.XXX
6(72 TOTAL)
 Analog
End of Frame LF, CR ASCII
2
 Inserted

NOTE:  Each parameter is followed by a space. The values for each of the 12 analog channels are separated by spaces.
* These values are not valid below an aircraft altitude of 10 km.
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4.2 RS 232 Time Channel Data Format

Data from the GPS time and date labels are read, translated and formatted. This data is sent on the RS232 Time Channel at 9600 baud. The date is Julian and the time is Universal Coordinated Time (UTC). The string is terminated by a carriage return and line feed. The effective time begins at the first character of this frame with less than 0.1 milliseconds of delay. The output format (in ASCII) is as follows:

DATE_ _XXX_ _TIME_ _XX:XX:XXCRLF [27 characters total]
CR = Carriage Return
LF = Line Feed

The Nav Recorder also broadcasts an IRIG-B time code to all payload areas.


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