Mechanical-scan radar pedestal alignment tool

This work aims to develop a system that can correct the misalignment between a mechanical scan radar and the pedestal on which it is installed. The pedestal is used to move the radar about its azimuth and elevation axes. When the system is assembled, due to mechanical tolerances, the mechanical and the electrical zeros are not aligned, and an offset is present. To measure it, the onboard analog rotation sensor called resolver is used. This sensor has a primary and two secondary windings, placed at 90° relative to each other; given an input voltage VIN, and the output voltages Vcos and Vsin, it is possible to evaluate the angle as the arctangent of the ratio of Vsin and Vcos. It is requested to design a stand-alone instrument to measure the offsets with high accuracy and store the values in an EEPROM installed on the pedestal to allow the calibration of the antenna. This new instrument will replace the currently used that is obsolete and non-stand-alone. Before proceeding with the design, it is investigated whether something similar already exists or was developed before and which is the actual knowledge about the system to ease the process and the risk of error during the realization. It is found that no devices able to fulfill all the requirements currently exist, however, the company had already developed an instrument for a similar purpose that is used as a starting point. Once the system has been developed and assembled, it is tested for its proper functioning and wanted performance. It is evaluated accuracy by using voltage dividers to simulate the angles voltages and by comparing the angles retrieved with those got from a reference instrument (i.e. voltmeter), and repetitiveness by verifying that repeated measurements of the same angle do not have significant deviations. Once accuracy and repetitiveness are evaluated, end-of-line tests are performed: these tests verify that the system works as expected, especially if more devices are produced.