To track the movement of the copter in flight, a stable IMU with minimal swing effect has to be used. There are several low cost IMU's available on the market, similar to the one in the flight controller. While these are great for tracking instantaneous movement, they are not good at tracking movement over time. Due to noise and swinging of the gyro while accelerating in any direction, the tracking will be skewed while moving up and down the cave. This mostly results in incorrect or unreliable scanning data.
Xsens Technologies are well known in the industry for producing stable and accurate IMU's. Their product series \href{https://www.xsens.com/products/mti-1-series/}{MTi 1} features all the specifications needed for the copter and was chosen as the primary IMU for the project.
