MODAPS PCR 07-019
| PCR Number | 07-019 |
|---|---|
| Date | 2007-10-18 |
| Initiator | James Kuyper |
| Abstract | Several minor updates to PGE01. |
| Problem Statement | This PCR addresses several minor unrelated issues at one time: Bug 194: MOD_PR03 uses the SD start time to calculate the solar "elevation"angle Bug 199: If too many scans are split by bit-flipped packets, MOD_PR01 will attempt to write a 209th scan. Bug 258: MOD_PR03 ignores bit 18 of the attitude quality flags. Bug 484: If a bit flip corrupts a packet time stamp, inserting that packet between two different scans, rather than within a scan, MOD_PR01 does not identify it as being out-of-sequence. Spline interpolation of the mirror motion is performed separately for each frame. |
| Description of Change | Bug 194: Use the EV center time to calculate the solar elevation angle. Bug 199: Change to prevent unnecessary creation of empty scans, and to halt writing to the output file at 208 scans. Bug 258: Change to use the platform-fatal bit, which is set when any platform-specific fatal bit is set, including bit 18 for Aqua. Bug 484: Correct the code which checks for inconsistencies between the packet count and the time stamp, so that it works as originally intended for out-of-sequence packets that are found between scans. Perform spline interpolation of the mirror motion for all 1354 frames of a scan at one time. |
| Products Affected | M[O|Y]D01, M[O|Y]D03 |
| Software Affected | PGE01 |
| Processing String to Receive the Change | Terra Forward, Aqua Forward |
| Downstream Product Effects | Since the L1B program cannot process scans containing EV data that has been split away from the SD data, preventing such splits will, on rare occasions, increase the number of scans of data available for all downstream products. |
| Data Granules to be Used for Science Testing | 2007-238 11:00/13:00 |
| Justification | Bug 194: A data gap that ends while the mirror is between the start of the SD sector and center time of the EV sector unnecessarily prevents geolocation for the entire scan. Note: L1B cannot calibrate EV data without the corresponding SD data, which reduces the value of fixing this. Bug 199: The MOD01 SDSs are created with room for only 208 scans. Bug 258: For the Aqua satellite (only) bit 18 indicates that the attitude data was unprocessed. Bug 484: When a bit flip corrupts a packet timestamp, inserting it randomly between two valid packets, 2/3 of the time it will arrive between packets belonging to different scans. Performing spline interpolation of mirror motion for all 1354 frames, once per scan, makes MOD_PR03 run 20% faster. |
| Effective Date for Implementation of Change | |
| Status |
