**1. Introduction**

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Radar sensors offer in general the capability to measure extremely accurately target range, radial velocity, and azimuth angle for all objects inside the observation area. These target parameters can be measured simultaneously even in multiple target situations, which is a technical challenge for the waveform design and signal processing procedure. Furthermore, radar systems fulfil these requirements in all weather conditions, even in rain and fog, which is important for all automotive applications, [1], [2]. Advanced driver assistant systems (ADAS) are currently under investigation to increase comfort and safety in general. For Adaptive Cruise Control (ACC) applications a single 77 GHz radar sensor is used, which has a maximum range of 200 m and covers a narrow azimuth angle area of 15 degree for example. Many other and additional automotive applications, like Stop & Go, Pre-Crash or Parking Aid, consider a completely different observation area [3]. In this case a maximum range of 50 m, but a wide azimuth angle area of 120 degrees is required. For these applications 24 GHz radar sensors are used. Besides the range and velocity parameters, additional information concerning the target type are of great interest, as one of the main objectives of future safety systems will be the increased protection of all pedestrians and other vulnerable road users.

By extending the radar signal processing part of a 24 GHz radar sensor with a pedestrian recognition scheme, the same radar sensor which is used for the mentioned applications can be applied additionally for pedestrian recognition and allows the design of pedestrian safety systems. Therefore, the radar signal processing part has to be adapted to the assumption of extended targets with a characteristic range profile and a velocity profile (e.g. based on the Doppler Spectrum) in general [4]. The detailed analysis of the resulting range profile and target's velocities is possible and can be used to recognize pedestrians in urban areas with conventional 24 GHz radar sensors.
