# Testing Procedure of Unmanned Aerial Vehicles (UAVs) Trajectory in Automatic Missions
## 2 Materials and Methods-Test Tasks for UAVs and Field Works
It is worth noting that it is possible to use these tests as versatile ones, which can be carried out almost anywhere. The following tasks have been specified:  
* Task 1--aimed at determining the hovering accuracy by the UAV. The device has been programmed to reach the point having specific coordinates and then to maintain the position. This point has been located 30 m above the ground. Such measurement conditions has allowed for me to assume that the device has been subjected to laminar wind flow only and it has not been disturbed by turbulences from terrain obstacles. This is one of the basic tasks with the main purpose of controlling the position of the UAV during the hovering to examine the device position drift during its flight. * Task 2--based on five waypoints that have been the ends of the sections covered by the UAV. The waypoints have been placed on the base and arranged in a cross, whose arms have been parallel to the directions of the world, with each arm being 25.00 m in length (counting from the centre of the base). Figure 1 illustrates an outline of the base. The motivation to define this task has been determining the basic parameters of the UAV work in the aspect of the ISO standards for industrial robots. * Task 3--aimed at verifying the accuracy of the barometric system that was installed in the UAV, responsible for the correct implementation of the programmed flight altitudes. This task has assumed a gradual attainment of successive altitudes, previously programmed in 5 m intervals between 20 and 90 m.
* Task 4--there has been a simulation of a photogrammetric mission in which the device has been programmed to perform a mission over a given area. The trajectory of the changed direction of the flight has been used here by stopping at the programmed waypoint, and then turning and continuing the way to the next point. Figure 2 illustrates an outline of the base. * Task 5--there has also been a simulation of a photogrammetric mission as in task 4, with the exception that it has been using the trajectory of the changed direction of the flight in which the UAV does not stop at the turn point, but it makes a smooth turn towards the next point. The forward speed of the device is adjusted to the turn automatically by the UAV on-board computer. The aim of tasks 4 and 5 was to verify the accuracy of the realization of photogrammetric missions by the UAV and to analyse its influence on coverage of the images. The proposed set of tasks is flexible. It is worth mentioning that the sizes of the test bases that are described above can be individually adjusted to the device being the object of interest. It is also important to pay attention to the target tasks for the UAV before which the tests are performed; for example, the maximum altitude tested in Task 3 should be adjusted to the planned UAV flight parameters during the mission. Figure 1: Outline of measurement base in task 2. Figure 2: Outline of measurement base in task 4 and 5. The tasks that are described above were tested several times during the field works, which have consisted in the measurements performed on two the same DJI A2 on-board computers in two types of weather conditions. The DJI A2 multi-rotor stabilisation controller is a complete flight control system for various multi-rotor platforms. Flight controller supports many UAV's functions, such as control of the gimbal and the camera, the FaiSafe activation, changing control mode, intelligent orientation control, low voltage protection, and parachute activation. The A2 flight control system uses the controller unit as its core, which is connected with the IMU, GNSS-COMPASS module, Power Management Unit (PMU), and Electronic Speed Controllers (ESC). The lock of altitude and position of the UAV during a flight is achievable thanks to the IMU and the GNSS. All on-board systems contribute to the hovering accuracy of the UAV that is equipped with DJI A2 declared by the manufacturer, which is: \(\pm\)0.5 m (vertical) and \(\pm\)1.5 m (horizontal).