Ultrasonic sensors are popular in parking functions in automotive. They are used to measure distances between a car and obstacles near the car. Car companies need to prove that sensors are reliable before using them on vehicles since these sensors are safety-critical. Therefore, it has great practical value to research on the measurement and verification of ultrasonic sensors. The purpose of this thesis work is to analyse analog parts of some ultrasonic sensors. Measurement methods and three experimental setups are designed to get analog data. Ice, soil, stones or some other things on the road might cover the sensor, which limits the movement of horn and causes measurement errors. Sensor impedance is measured to check the possibility of blockage situation detection in a simulation of a real environment. The work also includes analysing the ultrasonic sensor beam pattern, the sound reflection from the environment, noise reduction, the relationship between the signal voltage amplitude and different positions of sensors, influences on different input signal lengths, and bandwidth investigation of the ultrasonic sensor. MATLAB compares measurement results with theory or simulation, All methods and setups are validated by getting measurement results successfully and correctly. Sensor blockage situation is recognized clearly by different impedance magnitudes. Sensors types under study are different from sensors installed on cars. However, other ultrasonic sensor measurements can utilize the same measurement methods and experimental setups. This thesis has been performed in collaboration with the company Volvo Car Corporation active safety department.