Estimating Altitude of Drones Using Batteries

摘要

With the rise of drone technology, both new possibilities and new problems are presented in an expanding variety of applications. One such application is the use of drones to establish temporary mobile networks over a small area in the event of a catastrophe or environmental disaster, however this may require establishing the location of a drone without GPS data or other location sensors. In such cases, external battery readings may be used to characterize drone behavior and predict its location. Alternatively, to defend against cyberattacks drone battery data may be used as an authentication method by verifying internal sensor readings against separate measurements from an external system, validating of internal readings and detecting abnormalities. By analyzing certain characteristics of battery current draw and voltage readings, specific drone behaviors can be determined or predicted. The focus of this research study is to determine what classifications or predictions of drone flight behavior may be made using external battery readings alone, and to explore if the problems outlined above are solvable through this method. Data was collected using a DJI Mavic Air drone with an externally attached microcontroller over a series of controlled flight patterns. Internal sensor readings from the DJI Mavic Air drone, including altitude and acceleration, are stored in onboard flight logs and were used to validate the externally measured data. Battery readings were taken externally using an Arduino-based system that bridges the physical connection between the battery and the drone body, measuring and logging the cumulative current draw and voltage of the battery while the drone is in flight. From this data we were able to develop programs to accurately classify the drone state as being in takeoff, hovering, ascending, descending, or landing. We were also able to find a relationship mapping cumulative battery current draw to acceleration. Using the detected flight state in conjunction with the calculated acceleration, our program is able to accurately estimate the altitude of the drone using only externally measured cumulative battery current.