Comparing quadcopter iMET Temperature, Pressure and Humidity data with 10 m tower data

Collecting atmospheric data using Unmanned Aerial Vehicles (UAVs) is very much in its infancy. Apart from navigating Federal Aviation Administration (FAA) regulations and resolving technical issues such as automated launch and recovery, there is a lot to be learned regarding meteorological sensor performance. InterMet Systems Inc. has recently developed the iMET XQ sensor specifically for use on rotary-winged UAVs. This low-cost, light weight sensor includes a GPS receiver and a rechargeable battery (battery life is 90 minutes). With 16Mb of storage on board the sensor, all data can be stored to internal flash memory and downloaded post-flight via USB. The sensor will be mounted on top of a 3DRobotics Iris+ quad-copter. The Iris+ will be programmed to hover at 2 and 10 m elevation near temperature, humidity and pressure sensors on a stationary 10 m tower. Data will be averaged over 1-min intervals just like is done for data collected by the weather station sensors. To determine if the orientation of the sensor impacts the quality of the data collected, the quadcopter will be rotated so the iMET faces in different directions. Two to three 30 min flights per week will be performed over a period of 4 months during different weather conditions and during different times of the day. Therefore, large enough samples will be collected, so that comparisons will be statistically significant. Furthermore, a large sample will allow data to be stratified by wind speed, wind direction, iMET orientation, and other weather conditions.

Additionally, two iMET sensors will be mounted on the weather station tower cross-arm at 2 m to make direct comparisons with the tower sensors. This will test the performance of the sensors without being mounted on a moving platform with rotating wings which can potentially affect airflow. One iMET will be placed in a radiation shield mounted on the tower, the other will be exposed. The temperature sensor on the iMET is aluminized to reduce IR and UV effects. Comparing measurements from an exposed iMET with an iMET in a radiation shield, will reveal the effectiveness of the aluminzation.