Skip to content. | Skip to navigation

Personal tools
You are here: GES DISC Home Precipitation Documentation TRMM_README SSIs TRMM_readme_PR_Scan_Status.shtml


TRMM PR Scan Status
Name Format Values Description
Missing 1-byte integer Value and meaning Indicates whether information is contained in the scan.
Validity 1-byte integer Bit and meaning A summary of status modes.
QAC 1-byte integer 0: No decoding error occurred. The Quality and Accounting Capsule of the Science packet as it appears in Level-0 data.
1-byte integer Bit and Meaning A summary of geolocation quality in the scan.
Data Quality 1-byte integer Bit and Meaning A summary of data quality in the scan.
Current Spacecraft
1-byte integer Value and Meaning Current spacecraft orientation.
Current ACS Mode 1-byte integer Value and Meaning Current ACS mode.
Yaw Update Status 1-byte integer 0: Inaccurate
1: Indeterminate
2: Accurate
Yaw update status.
PR Mode 1-byte integer 1: Observation Mode
2: Other Mode
PR mode.
PR Status 1 1-byte integer 0: Normal
1: A little questionable
A warning for scan data.
This field is used only for NASDA's data analysis.
PR Status 2 1-byte integer 0: Not initialized
1: Initialized
Initialization in Onboard Surface Algorithm.
Orbital Number
4-byte float   The orbit number and fractional part of the orbit at Scan Time.
The orbit fraction part is calculated as:
(Time-Orbit Start Time)/(Orbit End Time-Orbit Start Time)

Value and Meaning of Missing
Value Meaning
0 Scan data elements contains information
1 Scan was missing in the telemetry data
2 Scan data contains no elements with rain

Bit and Meaning of Validity
Bit Meaning if bit=1
0 Spare (always 0)
1 Non routine spacecraft orientation (2 or 3)
2 Non routine ACS mode (other than 4)
3 Non routine yaw update status (0 or 1)
4 Non routine instrument status (other than 1)
5 Non routine QAC (non-zero)
6 Spare (always 0)
7 Spare (always 0)

Bit and Meaning of Geolocation Quality
Bit Meaning if bit=1 for Non-routine Situation Routine Situation
0 Latitude limit error If all status modes are routine, all bits in
Validity = 0. Routine means that scan data has
been measured in the normal operational situation
as far as the status modes are concerned. Validity
does not assess data or geolocation quality. Validity
is broken into 8 bit flags. Each bit=0 if the status
is routine but the bit = 1 if the status is not routine.
Bit 0 is the least significant bit (i.e., if bit i=1 and
other bits = 0, the unsigned integer value is 2**i).
1 Geolocation discontinuity
2 Attitude change rate limit error
3 Attitude limit error
4 Satellite undergoing maneuvers
5 Using predictive orbit data
6 Geolocation calculation error
7 not used

Bit and Meaning of Data Quality
Bit Meaning if bit=1 Note
0 Missing Unless this is 0 (normal), the scan data is
meaningless to higher processing. Bit 0 is the
least significant bit (i.e., if bit i=1 and other
bit = 0, the unsigned integer value is 2**i).
5 Geolocation quality is not normal
6 Validity is not normal

Value and Meaning of
Current Spacecraft Orientation
Value Meaning
0 +x forward
1 -x forward
2 -y forward
3 Inertial -- CERES Calibration
4 Unknown Orientation

Value and Meaning of
Current ACS Mode
Value Meaning
0 Standby
1 Sun Acquire
2 Earth Acquire
3 Yaw Acquire
4 Nominal
5 Yaw Maneuver
6 Delta-H (Thruster)
7 Delta-V (Thruster)
8 CERES Calibration
Document Actions
NASA Logo -
NASA Privacy Policy and Important Notices
Last updated: Sep 09, 2009 02:26 PM ET