Changes between Version 20 and Version 21 of TBR/UserApp/MMS_Instruments_Suite


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Timestamp:
Dec 6, 2011, 1:27:07 AM (8 years ago)
Author:
Ivaylo
Comment:

/* Instrument Description */

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  • TBR/UserApp/MMS_Instruments_Suite

    v20 v21  
    6262The MMS instrumentation consists of three major systems:
    6363
    64     An air motion sensing system to measure the velocity of the air with respect to the aircraft, i.e., the true air speed.
    65     An inertial navigation system to measure the velocity of the aircraft with respect to the earth, i.e., the ground speed.
    66     A data acquisition system to sample, process and record the measured quantities.
     64    *An air motion sensing system to measure the velocity of the air with respect to the aircraft, i.e., the true air speed.
     65    *An inertial navigation system to measure the velocity of the aircraft with respect to the earth, i.e., the ground speed.
     66    *A data acquisition system to sample, process and record the measured quantities.
    6767
    6868The air motion sensing system consists of sensors, which measure temperature, pressures, and airflow angles (angle of attack and yaw angle). The Litton LN-100G Embedded GPS Inertial Navigation System (INS) provides the aircraft attitude, position, velocity, and acceleration data. On the DC-8, the Trimble TANS Vector provides secondary attitude and navigation data. The TANS Vector utilizes the GPS carrier phase shift between multiple antennas to derive independent aircraft attitude. The Data Acquisition System samples the independent variables simultaneously and provides control over all system hardware.
     
    7474The system calibration of the MMS consists of:
    7575
    76     Individual sensor calibrations.
    77     Sensor dynamical response tests.
    78     Laboratory determination of the dynamic behavior of the inertial navigation system.
    79     In-flight calibration.
    80     Comparison with radiosonde and radar-tracked balloons.
     76    *Individual sensor calibrations.
     77    *Sensor dynamical response tests.
     78    *Laboratory determination of the dynamic behavior of the inertial navigation system.
     79    *In-flight calibration.
     80    *Comparison with radiosonde and radar-tracked balloons.
    8181
    8282Individual sensors are routinely re-certified to NIST standard by their respective calibration laboratories. Specific MMS sensor configuration are tested rather than the nominal set-up. For example, a temperature bath calibration is determined for a specific platinum sensor matched to a specific signal conditioner. Another example is that the recovery correction for a specific temperature probe is re-established by wind tunnel testing.
     
    8989
    9090Power spectra of the measured quantities are finally analyzed to determine the resolution and noise figure. Independent spectral and fractal analysis of the MMS data are documented in Bacmeister [1996] and Tuck [1999].
     91= DC-8 MMS Instrument Improvement =
    9192
    92 DC-8 MMS Instrument Improvement
    9393
    9494To increase system performance and reliability, we propose to improve the following DC-8 MMS sub-systems:
    9595
    96     The current dynamic and static pressure measurements include very long pneumatic lines, which span the width and half the length of the DC-8 fuselage. The long lines have proven to be unreliable and prone to leakage. The long transmission line system shows significant signal propagation time delays, oscillations, and frequency dependent damping. Dedicated transducers will sample the outside pressure with a 12-inch connecting line. The payload integration will require minor mechanical and electrical efforts for the transducer installations.
     96    *The current dynamic and static pressure measurements include very long pneumatic lines, which span the width and half the length of the DC-8 fuselage. The long lines have proven to be unreliable and prone to leakage. The long transmission line system shows significant signal propagation time delays, oscillations, and frequency dependent damping. Dedicated transducers will sample the outside pressure with a 12-inch connecting line. The payload integration will require minor mechanical and electrical efforts for the transducer installations.
    9797
    9898    We also plan to replace these transducers with vibrating quartz digital pressure sensor, with temperature compensation from ParoScientific. The ParoScientific transducers have significantly better accuracy (0.01% compared to Rosemount's 0.1% full scale) and lower long-term drifts. The improvement in the pressure measurements translates to higher accuracy in static pressure, static temperature, and wind products.
    9999
    100     We propose to update the data system to operate autonomously similar to the ER-2 MMS without an operator on-board during a science flight. An operator at the console, in the passenger cabin, is still a requirement during the testing and validation phase. The instrument is operated with a simple on/off switch. This improvement reduces the seat requirement during science flights and reduces the number of field personnel.
     100    *We propose to update the data system to operate autonomously similar to the ER-2 MMS without an operator on-board during a science flight. An operator at the console, in the passenger cabin, is still a requirement during the testing and validation phase. The instrument is operated with a simple on/off switch. This improvement reduces the seat requirement during science flights and reduces the number of field personnel.
    101101
    102     Special pilot induced flight maneuvers are required to calibrate and to validate system performance on each flight. The calibrating maneuver typically includes 5 sinusoidal ± 2° of pitching, 5 sinusoidal ± 2° of yawing, and 360° square box pattern. The pitch and yaw maneuvers consume negligible flight time; they are usually executed in transit. It takes the DC-8 about 10 minutes to complete the four 90-degree of the box pattern. We have developed a new calibration algorithm and reduced the box pattern frequency by half.
     102    *Special pilot induced flight maneuvers are required to calibrate and to validate system performance on each flight. The calibrating maneuver typically includes 5 sinusoidal ± 2° of pitching, 5 sinusoidal ± 2° of yawing, and 360° square box pattern. The pitch and yaw maneuvers consume negligible flight time; they are usually executed in transit. It takes the DC-8 about 10 minutes to complete the four 90-degree of the box pattern. We have developed a new calibration algorithm and reduced the box pattern frequency by half.
     103= ER-2 MMS Instrument Integration =
    103104
    104 ER-2 MMS Instrument Integration
    105105
    106106The ER-2 MMS last performed in January-March 2000 during the Sage Ozone Loss Validation Experiment. The instrument is flight ready and only needs installation on to the CAMEX-4 ER-2 payload. Because the CAMEX payload utilizes a special nose for the ER-2 Doppler Radar (EDOP), the MMS temperature sensors and airflow angle system need to be installed. We have made a preliminary assessment with the ER-2 Engineering Technical Lead at Dryden Flight Research Center.