Advanced Features

The following section provides and overview of the Reflex's advanced features along with how they can each be configured. These features may be enabled to improve flying quality.

Takeoff and Landing Detection

This feature enables the Reflex to detect the takeoff and landing states of the drone, allowing it to perform actions like disarming due to takeoff timeout and after landing.

To ensure the effectiveness of this feature, there are limitations on the maximum bank angle when the drone is close to the ground. These limitations include:

  • Touchdown Height: Below this height from the ground, the bank angle is constrained to zero.

  • Coning Distance: Above the touchdown height, there is a coning distance within which the maximum allowable bank angle setpoint gradually scales down to zero from maximum bank angle until it reaches the touchdown height.

The pilot regains full bank control authority above the touchdown height plus the coning distance.

Additionally, the feature restricts horizontal forces and throttle when the drone is on the ground before takeoff and after landing.

For optimal performance of this feature, it is recommended to enable the bank angle limitation and the associated actions.

To enable auto-disarm on landing, ensure the throttle stick is fully down in piloted modes, and avoid any horizontal movement commanded by the pilot. In automated modes, no additional pilot intervention is required for auto-disarm.

Web Interface: Settings > Commander > Takeoff And Landing Detection

RPM Notch Filter

The RPM notch filter aims to minimize noise picked up by the flight controller's internal IMUs that is caused by vibrations from the rotors. This feature allows the user to configure a set of notch filters whose centre frequencies will dynamically change to attenuate the frequencies of each of the motors.

Note: This feature relies on feedback of the motor RPMs and thus is only functional when the Bidirectional DShot protocol is being used.

To enable and configure the RPM notch filter, navigate to the following location from the web interface:

Web Interface: Settings > Internal Sensors > IMU RPM Notch Filter

Here, the following parameters need to be configured:

  • Bandwidth: The frequency range around each notch filter's centre frequency which should be attenuated.
  • Minimum Frequency: The lower bound of frequencies which should be attenuated by the notch filters. If the measured motor frequencies are below this value, then the data will not be filtered.
  • Fade Range: The range of frequencies above the Minimum Frequency during which the filter effect is linearly faded in/out. For example, if the Minimum Frequency is set to 30Hz and the fade range is set to 10Hz, then the filters have no effect at 30Hz and linearly increase in effectiveness until they are fully effective at 40Hz. The purpose of this is to avoid sudden changes in computation of the filters, which could lead to numerical instability.
  • Number of Harmonics: The feature can also be configured to filter out the first three harmonics of the motor frequencies to account for noise induced by the propellers. It is recommended that the number of harmonics chosen to be filtered corresponds to the number of blades on the propellers. For example, if using three bladed propellers, it is best to set the number of harmonics to three.