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General Introduction
ITARD-024SA is high-performance narrow-beam flat radar. It is an auxiliary product in the ITS
area of considerable integration and intelligent level. It is to detect the moving vehicle
dynamically to promote the modern management level of the road and city traffic.
ITARD-024SA realizes the vehicle detect via the Doppler effect theory. The radar sends out a ray
of microwave, and the microwave is reflected after it touched the moving vehicle. The radar can
receive the reflected wave. If the object has the radial movement relative to the radar, the
frequency of the reflected wave is different from the frequency of the send out wave. At the same
time, the difference of the frequency is proportion to the relative moving speed of the object and
the radar. Now the radar can detect the difference between the reflected wave and the send out
wave to calculate the moving speed of the vehicle.
The radar that used to detect the vehicle speed shall meet some basic requirements.
First, the antenna of the radar shall have sound direction capabilities. The wave beam shall not
be too wide. Otherwise, there are several lanes in the radar detect area at the same time; the
radar can not distinguish the object and can not calculate the speed. In the actual environments,
we can see the wave beam level width of the radar shall be less than 7°. The ITARD-024SA
adopts the 4.6°angle. To avoid the interference from the vehicle out of the beam, the side lobe
level of the antenna direction shall be general low. Usually it shall be less than
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15dB. The
ITARD-024SA adopts
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21.5 dB. At this value, it can effectively reduce the interference from the
neighboring lane. Besides, to accurately locate the vehicle position, the trailing edge of the radar
beam shall be steep, the typical and the wave beam-shape factor (
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20dB width/
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3dB width)
shall be less than 2.5.
The second requirement is speed measuring responsive time. It is the delay time from the object
enters the detect area to the radar gives the speed data. ITARD-024SA adopts the following
principles: for the vehicle of slow speed, the speed measuring responsive time is general long
and for the vehicle of high speed, the speed measuring responsive time is short. In this way, the
vehicles of all speeds are in the specified distance so that the camera can get the clear plate
information.