Communications: electrical – Vehicle detectors
Reexamination Certificate
2002-05-29
2004-08-10
La, Anh V. (Department: 2636)
Communications: electrical
Vehicle detectors
C340S905000, C340S901000, C701S023000
Reexamination Certificate
active
06774817
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a reflection multiplier radio wave marker system which employs a radio wave lane marker installed in the surface of a road for providing a vehicle with information about location in the width direction in a traffic lane and road status, and to a traffic system.
BACKGROUND OF THE INVENTION
FIG. 6
shows a conventional radio wave marker system. In
FIG. 6
, a reflection multiplier radio wave marker (hereinafter referred to as marker)
54
is installed in the surface of a road, while a marker sensor
60
, which is formed of a transmit antenna
55
, a receive antenna
56
and a detection•processing portion
57
, is mounted on board a vehicle.
The transmit antenna
55
transmits electric wave to a marker
54
, the electric wave reflected by the marker
54
is received by the receive antenna
56
. The detection•processing portion
57
processes the signal received to calculate location of the vehicle in relation to the marker
54
.
Referring to
FIG. 6
, one unit of transmit antenna
55
is disposed substantially in the middle; while the receive antenna
56
is disposed for three units, in the left, in substantially the middle and in the right.
Intensity of the electric wave reflected by a marker
54
is higher when the marker
54
is located closer to the transmit antenna
55
of marker sensor
60
. Receiving sensitivity at a receive antenna
56
of marker sensor
60
goes higher when it is located closer to marker
54
.
When distance between a marker
54
and a transmit antenna
55
, or a receive antenna
56
, of marker sensor
60
exceeds beyond a certain range, the marker sensor
60
becomes unable to detect the marker
54
.
Being dependent on the shape and size of a transmit antenna
55
mounted at the front of a vehicle, it is difficult for a conventional radio wave marker system to detect location of a vehicle in relation to a marker
54
in the direction of width covering the entire range of a vehicle width. Namely, if a single transmit antenna
55
is to cover the entire range of a vehicle width evenly, it should be a loop antenna whose size is identical substantially to the vehicle width. In practice, such a loop antenna poses a great restriction in mounting it on board a vehicle.
In order to enable a vehicle to detect the location in relation to a marker in substantially the entire range of the vehicle width using a means mounted at the vehicle front, the transmit antenna
55
needs to be made compact in size and high in sensitivity. These are not easy tasks to achieve.
SUMMARY OF THE INVENTION
A reflection multiplier radio wave marker system which comprises a plurality of transmit antennas mounted on board a vehicle for transmitting electric wave signals in a first frequency; a reflection multiplier radio wave marker installed in the surface of a road, which reflects and transmits the electric wave signal of first frequency after multiplying it into an electric wave of a second frequency; and a receive antenna mounted on board the vehicle for receiving the electric wave of second frequency. The system detects location of the vehicle in a traffic lane based on the second frequency electric wave signal reached from a marker. Range of the location detection is extending to cover substantially the entire width of the vehicle.
REFERENCES:
patent: 3813497 (1974-05-01), Wachs et al.
patent: 5451941 (1995-09-01), Lamazou
patent: 5889478 (1999-03-01), Minesi
patent: 6097312 (2000-08-01), Tanji
patent: 6173005 (2001-01-01), Kotzin
patent: 1103938 (2001-05-01), None
patent: WO 00/72288 (2000-11-01), None
European Search Report for EP 02 01 1937, dated Aug. 26, 2002.
Handa Satoru
Tanji Yoshihiko
La Anh V.
Matsushita Electric - Industrial Co., Ltd.
LandOfFree
Reflection multiplier radio wave marker system and traffic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reflection multiplier radio wave marker system and traffic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reflection multiplier radio wave marker system and traffic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3353082