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In the presented paper we deal with an important problem in active safety systems, which is the multi-rate processing of different signals. Automotive systems are usually very complex, involving multiple subsystems, in which typically it is very difficult to obtain equal sampling rates. In many cases, this problem is ignored, which means that the signals samples stored in different time moments are silently assumed to be to sampled in the same time. Looking from the point of view of signal processing, this incorrect assumption often causes large harmonic distortions artifacts of processed signals. These distortions, in turn, generate harmonics of different frequencies. As a result, if processed signals are used to calculate the trajectories of objects seen by systems associated with the vehicle, may differ from the real world trajectories. This may cause occurrence of false positives or no reaction of the vehicle in case of emergency situation.

In this paper we present an example design process of filters used in automotive industry. Signal preprocessing is very important operation in active safety algorithms. Such algorithms usually take into account the vehicle state that includes position, velocities and accelerations of the car. On the basis of these data, as well as the parameters and trajectories of external objects “observed” by the car, the algorithms make decisions about various safety actions. Designer of such algorithms must assure an appropriate quality of such signals, which usually means a proper filtering. In this paper we focus on selected important aspects of the filter design process. The main objectives of the presented investigations is to obtain such filters that ensure a sufficient rejection of undesired components from the signal and at the same time that do not introduce too high delay to the processed signals.