Impact of GNSS antenna calibration model for attitude estimation in UAV platform

The recent increase of unmanned aerial vehicles (UAVs) in both military and civilian usage stems mainly from modern navigation technologies and from their abilities to accomplish different tasks in a quick, safe, and cost-effective manner. One sector that witnessed significant UAV impact is the emerging Information and Communication Technology (ICT) field, in particular the branch of UAV trim and antennas calibration. In fact, navigation and positioning of drones is carried out through GNSS satellite positioning, which is a fundamental aspect for navigation, remote operation and flight safety. Unfortunately, the acquisition of emitted satellite signals, performed by onboard drone antennas, are extremely affected by noise due to electromagnetic disturbances, radio interferences and other bias. Therefore, it is clear how the antennas calibration is extremely important, particularly the low-cost ones. Typically, antennas tests are performed inside anechoic chambers, where the radiation pattern can be estimated with high precision. However, high precision often requires the use of high-cost instrumentation. In this scenario is mandatory to develop cost-effective methods to characterize UAV antennas. A possible solution to this phenomenon is using a multi antenna GNSS measurement system. These kinds of measurements, although less accurate than those performed in anechoic chambers, allow a more realistic performance analysis due to multipath contributions in ground, surrounding structures, and drastically reduce the equipment cost. The main objective of this thesis is to calibrate antenna under tests (AUTs) throughout the use of a non-conventional and cost-effective system. All tests of this project were carried out on two antenna models, microstrip patch and dual-frequency omnidirectional, and the workflow was divided as follows: -??control and calibration of antennas in an anechoic chamber, to collect precise and effective measurements; -??outdoor static data acquisition and post-processing of GNSS observations in order to validate the results of the anechoic chamber characterization; -??outdoor dynamic data acquisition to evaluate the heading estimation of the GNSS multiantenna system through the use of a rotation platform; -??a final study of the measurement system using a remotely piloted drone. The simulations showed how even through the use of unconventional methods it is possible to calibrate signal receivers while maintaining a high level of reliability of the results. Furthermore, being a method that uses low price equipment, this thesis wants to provide a valid alternative to an audience that has lower project budget.