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首页> 外文会议>European Automotive Congress >A BROAD BEAM DOPPLER EFFECT SENSOR FOR THE MEASUREMENT OF THE ABSOLUTE SPEED OF A VEHICLE
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A BROAD BEAM DOPPLER EFFECT SENSOR FOR THE MEASUREMENT OF THE ABSOLUTE SPEED OF A VEHICLE

机译：用于测量车辆绝对速度的宽梁多普勒效应传感器

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The efficiency of many automotive applications, for instance the ABS, could be increased by exploiting the absolute speed of the vehicle instead of that derived from the rotation of the wheels. Indeed, the later may not reflect the real situation, particularly in high danger cases, for instance when the wheels are sliding on an icy or wet road surface. Thus, sensors using Doppler effect are being investigated. They take advantage of the frequency shift of a wave reflected by ground scattering obstacles. This shift, proportional to the vehicle speed, depends on the angle between the direction of the reflected wave and the road surface. Thus, the accuracy of the measurement depends on the knowledge of this angle. For this reason, conventional Doppler sensors use a narrow beam antenna in order to have a good accuracy on the angle. Such sensors are well suited to cases when the obstacle number is large. In some cases however, the probability of having scattering obstacles in the antenna footprint may be quite small, for instance when the road surface is icy, leading to the impossibility to perform the measurement. The present work was devoted to Doppler effect sensors using broad beam antennas in order to increase this probability. Two principles are proposed. The first one uses the simultaneous emission of two waves, a first one at a constant frequency and a second one which frequency is a function of time, whereas the second one uses the successive emission of these two waves. The measurements carried out with a laboratory set up and the results obtained by simulation techniques show that these sensors are particularly well suited for the above mentioned high danger situations when few obstacles are present on the road surface. In order to have a good accuracy for all road conditions, the directivity of the antenna can be electronically switched according to the obstacle distributions.
机译：通过利用车辆的绝对速度而不是从车轮的旋转来增加，可以增加许多汽车应用的效率，例如ABS。实际上，后来可能无法反映真实情况，特别是在高危险情况下，例如当车轮在冰冷或湿的路面上滑动时。因此，正在研究使用使用多普勒效应的传感器。它们利用由地面散射障碍物反射的波的频移。这种偏移与车速成比例取决于反射波和路面的方向之间的角度。因此，测量的准确性取决于该角度的知识。因此，传统的多普勒传感器使用窄光束天线，以便在角度上具有良好的精度。当障碍物数量大时，这种传感器非常适合于情况。然而，在一些情况下，在天线占地面积中散射障碍物的概率可能是非常小的，例如当路面是冰冷的时，导致不可能执行测量。使用宽光束天线致专用于多普勒效应传感器，以提高这种概率。提出了两项​​原则。第一个使用两个波的同时发射，第一频率处的第一一个波，第二个频率是时间的函数，而第二个是使用这两个波的连续发射。用实验室设置的测量结果和通过仿真技术获得的结果表明，当在路面上存在少量障碍时，这些传感器特别适用于上述高危险情况。为了对所有道路条件具有良好的精度，可以根据障碍物分布来电子切换天线的方向性。

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