This tutorial will focus on how to use an optical flow sensor as a means of GPS denied navigation
Note: Optical Flow Sensors are not robust, and should only be used to augment another method of position estimation such as SLAM
ardupilot has a built in optical flow simulated sensor. To use this we will launch the ardupilot sitl and set SIM_FLOW to 1 by runnning
param set SIM_FLOW 1
Disable the simulated GPS by typing
param set SIM_GPS_ENABLE 0
first we must enable the drone's EKF to use the optical flow estimates. to do this type
param set EK2_GPS_TYPE 3
Position estimation from optical flow is a methos that integrates velocity at each time step to form a position estimate. In order to do this we must tell the drone where to start integrating from. This will be done by setting the EKF origin. This can be done 2 different ways
-1.) Via a ground station -2.) Programically