This paper describes the results of our evaluation
of a pedestrian's radio wave reflection characteristics.
Recently, the demands made for safety systems, such
as the Forward Collision Avoidance Assistance System
(FCAAS), have been increasing. The radar sensors of
such safety systems have to be capable of detecting
not only vehicles but also pedestrians, bicycles,
and roadside objects. Furthermore, such a safety system
should be able to make a decision without any mistake
as to whether a collision occurs. Therefore, the radar
sensor must be capable of detecting objects with 100%
certainty up to a point immediately before a collision
would otherwise occur.
The reflection characteristics of radio waves from
a pedestrian were measured as part of the effort to
improve the pedestrian detection performance of the
radar sensor. A pedestrian's radio wave reflection
intensity is low, at about 15- 20 dB less than that
of the rear of a vehicle, and can vary by as much
as 20 dB. Evaluating these characteristics in detail
is a prerequisite to the development of a radar sensor
that is capable of detecting pedestrians reliably.
本報告では，歩行者の電波反射特性を評価した結果について述べる。近年，車両周辺監視などの安全システムに対するニーズが高まってきている。安全システム用の電波センサでは，車両だけでなく，歩行者，自転車，路側物などまで検出しなければならない。さらに，安全システムは衝突するかどうかの判断を誤りなく行わなければならない。そのため，電波センサは，衝突直前の距離に至るまで，物体を確実に検出する必要がある。
電波センサによる歩行者検出性能を向上させるために，歩行者からの電波反射特性を測定した。歩行者の電波反射強度は車両の後部と比較して15〜20dB程度低いこと，変動幅は20dB程度あることを確認した。これらの特性を詳しく評価することが，歩行者検出性能の高い電波センサの開発に繋がっていく。
