Multi-Rate Signal Processing Issues in Active Safety Algorithms 2016-01-0112
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 the literature many resampling methods have been proposed, including interpolation techniques. These methods are often very accurate, but require the use of complex filters. An additional difficulty in the active safety systems is that they have to be very fast. For this reason, the use of complex resampling methods is not feasible. In this paper we consider various resampling approaches. The main objective is to obtain very fast methods that introduce a delay no greater than that one sample. Investigations carried out show that a simple linear or parabolic interpolation can significantly improve the precision of active safety algorithms.