# Improvement of Hexacopter UAVs Attitude Parameters Employing Control and Decision Support Systems
## 3 Hexacopter Platform Architecture
The receiver can be connected to a mobile device (tablet or smartphone) or a laptop, on which a GCS (ground control station) platform is installed. The two components of the telemetry kit are illustrated in Figure 7: the transmitter mounted on the drone and the receiver in two connection options (Samsung tablet and HP Omen laptop), on which the Mission Planner GCS was installed. The video signal from the hexacopter is either stored on the GoPro camera's internal microSD card (when it has to operate in record mode) or transmitted in real time to the ground by means of the following chain: the GoPro camera is connected to the Tarot T4-3D gimbal via a special dedicated connector; the video signal is then transmitted to a 32-channel antenna operating in the 5645-5945 MHz frequency range. This communicates with a dual receiver (two built-in antennas for better signal reception) on 32 channels, on the same frequency of 5.8 GHz, and the image is displayed on a 7\" HD monitor. Following laboratory tests, for optimal operation of the transceiver chain, the transmitter was set to channel 4 (5645 MHz), and the receiver was set to channel 5 (5885 MHz), according to the frequency matrices in the specifications of each component. Figure 8 illustrates the composition and  
Figure 4: Connections diagram for hexacopter variant v1. Figure 5: Hexacopter assembly for variant v2. location of the video transceiver system from the hexacopter to the operator. The HD video monitor with the built-in receiver is shown in the tripod-mounted version, but it can also be mounted on the operator's radio remote control for easy observation of real-time images and gimbal control to obtain the desired frame during the surveillance, reconnaissance, investigation and shooting missions. The Pixhawk 2.4.8 flight controller (FMUv2) installed on the hexacopter v2 version, with the interfaces to various peripheral equipment, are illustrated in Figure 9.  
The flight controller hardware components are the following:  
* System-on-Chip STMicroelectronics STM32F427 Cortex-M4F 32-bit main microcontroller, operating frequency 180 MHz, RAM: 256 KB SRAM (L1), 2 MB Flash memory for writing instructions. * System-on-Chip STMicroelectronics STM32F100 Cortex-M3 32-bit, 24 MHz operating frequency, 8 KB SRAM (L1), 64 KB Flash memory for writing instructions. Figure 6: Blood diagram of hexacopter platform. Figure 7: Arrangement of the telemetry kit on the drone and on the ground. Embedded sensors on the motherboard: \(\bullet\) a 3-axis STMicroelectronics L3 GD20H 16-bit gyroscope sensor; \(\bullet\) a 14-bit STMicroelectronics LSM303D accelerometer/magnetometer sensor; \(\bullet\) an Invensense MPU-6000 3-axis accelerometer/gyroscope sensor; \(\bullet\) a TE Connectivity MEAS MS5611 barometer sensor. Also connected to the flight controller is an external GPS antenna/bus module consisting of a Ublox M8N GPS receiver sensor and a Honeywell HMC5883L digital compass sensor. For the subsequent analysis of the flight parameters both on the ground and in flight in archuCorter firmware, version v4.x, was employed and installed on the Pixhawk 2.4.8 AP motherboard. A laptop and a tablet were utilized for the ground control station on which the mission planner platform was installed and employed. In the v2 version, the drone powering was achieved with three Turnigy batteries, LiPo type with four cells, in 4S1P and 4S2P configurations, maximum supported current 12-24C, with capacities 12,000 mAh, 16,000 mAh and 20,000 mAh. The hexacopter presented in the two variants, equipped with avionics components and sensors, can be employed in a wide range of civil applications, as well as in the field of  
Figure 8: Video signal transmission–reception chain from hexacopter to the operator. Figure 3:0 Pixhawk 2.4.8 flight controller and the peripheral connection interfaces. homeland and national security. The solutions developed represent a relatively economic option in terms of the component acquisition costs and integration.