MMS
Point of Contact:
- T.P.Bui
- NASA/ARC
- Office Telephone: (650)604-5534
- E-mail: bui@mms.arc.nasa.gov
Brief Instrument Description of the
DC-8 Meterological Measurment System (MMS) -
| Principal Investigators: | T. P. Bui and L. Pfister |
| Co-Investigators: | S. W. Bowen, C. Chang, J.D.Day, B. Harness, A. Trias |
| Organization: | National Aeronautics and Space Administration Ames Research Center Mail Stop 245-5 Moffett Field, CA 94035-1000 |
The DC-8 MMS consists of three major systems: an air-motion sensing system to measure air velocity with respect to the aircraft, an aircraft-motion sensing system to measure the aircraft velocity with respect to the earth, and a data acquisition system to sample, process, and record the measured quantities.
The air-motion system consists of two airflow-angle probes, three total temperature probes, with different response time, a pitot-static pressure probe, and a dedicated static pressure system. All probes and sensors are judiciously located at specific positions of the fuselage. The aircraft-motion sensing system consists of an embedded GPS ring laser inertial navigation system (Litton LN-100G), and a multiple-antenna GPS attitude reference system (Trimble TANS Vector). The data system rack is located near station 840, and customized software was developed to control, sample, and process all sensors and hardware.
| Typical value at 40,000 ft | Accuracy | |
| Pressure | =~ 200 mb | +/- 0.3 mb or =~ 0.5% |
| Temperature | =~ 220 K | +/- 0.3 K or =~ 0.2% |
| Horizontal Wind | =~ 30 m s-1 | +/- 1 m s-1 or =~ 4.0% |
| Vertical Wind | < 1 ms-1 (Resolution: 0.1 m s-1) |
Secondary Products: (1 Hz & 5 Hz)
| Calculated: | potential temperature, true-air-speed, turbulence (0.8 - 1.5 Hz) |
| Measured: | positions, velocities, accelerations, pitch, roll, heading, angle of attack, angle of sideslip dynamic & total pressures, total temperatures. |
References: Chan, K. R., S. W. Bowen, and J. D. Day, Observation of Turbulence by DC-8 MMS, presented at the AEAP Virginia Beach Meeting, VA, April 1997. Bui, T. P., DC-8 Meteorological Measurement System, presented at the SONEX Workshop, NASA Ames Research Center, February 1997.
