The autonomous Aerosonde meteorological observation system consists of pressure, temperature, humidity, winds, and GPS location.
Pressure, temperature, and humidity are measured using three Vaisala RSS901 sensors, one mounted inside the fuselage and ducted to the freestream, and two mounted in pods underneath the wing, with temperature and humidity elements in the freestream airflow. A pressure line from a static probe is connected to the fuselage sensor. Winds are measured during a turning maneuver using a combination of scalar airspeed and GPS vector groundspeed data. The interface to the Vaisala RSS901s has been implemented to Vaisala specifications.
A ground check is done on the three Vaisala sensors before every flight. This is done by placing the sensors into a zero humidity chamber and also measuring the ambient pressure and chamber temperature. Ground check correction formulas specified by Vaisala are applied to the data.
A theoretical and practical error analysis and sensitivity study will be presented in this talk. This analysis takes into account sources of error from: sensor calibrations, nonlinear sensor behavior and temperature effects, the measurement algorithm, the GPS and other sources. Intercomparisons are also made with other meteorological measurement systems during field testing.