**5.1 Description of the new inspection process**

The UAV allows us to gather a set of high quality images and videos from where the physical parameters of all the infrastructure are extracted as (Azimuth, Tilt, Height, Antenna type, etc.) in a short time frame and by eliminating the human intervention. This process will be divided into the following steps:


**Figure 8.** *The automated inspection process scenario.*

#### **5.2 The automated inspection process scenario**

**Figure 8** describes the designed automated inspection scenario. In the 1st segment, the UAV is recording images of the feeder cables state from bottom to top. In the 2nd segment, the vehicle is measuring the height of the antenna and its azimuth, and will then capture 360° panoramic images of the area surrounding the tower. The measurement of the height and azimuth is made using the embedded sensors (GPS, Compass, Accel/Gyro, etc.). In the 3rd segment, the UAV captures a side view of the antenna to measure the tilts and define the type of the antenna. In the 4th segment, a global view of the infrastructure is captured. After completing this, the vehicle initiates the landing.

#### **6. Results and discussion**

We have presented and detailed the assembly and configuration process of the UAV and its components. Then, we considered a telecommunication relay inspection operation established by the human being by implementing the technique of using a quadrotor drone. These operations are carried out in order to protect the conditions of activities in order to regulate the operation and management of communication provided by telecommunication operators. Generally, these inspections require climbing and a visual inspection of the structure. Each structural element is checked and verified [19]. The structures examined are usually steel masts, steel and concrete towers, satellite dishes, sector antennas and rooftop telecommunication structures [20, 21], etc.

These inspections are entirely manual, a costly activity for infrastructure companies and cause problems for operators and users, and these inspections are time-consuming. For this and thanks to integrating tools such as 4K cameras, measurement sensors, etc. We have developed an on-site audit technology using a quadrotor drone, capable of inspecting any telecommunications site. These technologies provide detailed measurement and monitoring of the status and operation of critical equipment. However, when the condition of the infrastructure is closely and continuously monitored, the risk due to faulty equipment can be significantly reduced.

The quadrotor was developed to perform checks in hard-to-reach areas and altitudes to troubleshoot any issues. Some of these problems include telecommunication errors, burns and incorrect physical parameters, falls due to climbing the antenna, etc. It is in this context that we have introduced an audit intervention for different heights of telecommunication towers. An inspection operation was triggered for a 20 m high tower, carried out by the radio team of phone operator Mobilis – ALGERIA. During this operation, the aerialist recorded all the necessary time of various measurements of the physical parameters of the relay, namely the tilts, azimuths, heights, type of aerials, etc. Likewise, we considered the same tower, but this time based on a quadrotor drone. As soon as the drone completes its mission, the results obtained are evaluated using a comparative table describing the execution time of the two previous operations as indicated in **Table 1**.

The table details the duration of each step of the inspection process carried out with human support or using a quadrotor drone on a 20 m high tower. The human execution time in the "up turn and check feeders" step is much longer than the time it takes to be executed by the quadrotor drone, similar to the "down turn" step. Tower height determination, GPS (global positioning system) and azimuth points are


#### **Table 1.**

*The execution time of the 20 m tower.*

measured when the drone takes over the camera orientation and begins to determine the antenna type, so this does not doesn't take too long. The high sensitivity of the GPS & Compass sensor integrated into the drone allows more precise measurements than the traditional compasses used by the aerialist. The drone inspection time is 6 minutes, while the total time of all human inspection steps is 20 minutes. This means that the drone will save more time and avoid risks that may occur during this process.

The radio team has two towers of 40 and 70 m, to check whether the height can influence the execution time of all the UAV inspection stages or not. We have started a second measurement mission to be carried out. The balances obtained are compared with a histogram showing the execution time of the two operations, as shown in **Figure 9**.

Comparing the two operations, we can see that the 20m tower measured by the antenna operator takes 20 minutes, and the 70m tower takes 45 minutes, and regarding the operation performed by the drone, the 20m tower m took six minutes while that of 70 m is 14 minutes. We notice, at all tower heights, the duration of the UAV-based inspection operation is shorter than the traditional one. It means, the

**Figure 9.** *Comparative histogram of the inspection execution time for each tower.*

#### *Quadrotor-Type UAVs Assembly and Its Application to Audit Telecommunications Relays DOI: http://dx.doi.org/10.5772/intechopen.104254*

inspection carried out by the drone gives precision of the measurements, reliability of the information obtained and to save more time in such missions.

The quadrotor drone offers such inspections and thanks to its stability, rapid deployment, a wide angle of view, precision in the physical parameters measured, precious time saving and high quality panoramic images in real-time. In addition to that, all problems that may arise during such operations (burns, human error, falls, etc.) have been eliminated.
