Communications: electrical – Vehicle detectors
Reexamination Certificate
1999-08-05
2002-07-09
Lieu, Julie (Department: 2736)
Communications: electrical
Vehicle detectors
C340S934000, C340S935000, C340S936000, C340S937000, C340S941000, C340S942000, C340S943000
Reexamination Certificate
active
06417783
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a vehicle detector arrangement including a sensor with a solar power supply.
2. Description of the Related Art
Vehicle detection, for example for determining speeds, for counting vehicles or for classification, among other things for traffic routing and traffic information systems, is becoming more and more necessary and desirable due to the increasing traffic density. A means for identifying vehicles is disclosed, for example, by German Patent Document DE 27 54 117 C2, whereby it is required that the vehicles be equipped with a reply module that is evaluated at specific read locations arranged in the roadway area. Both the equipping of vehicles with readable reply units as well as the arrangement of read stations in the roadway area are relatively complicated and cost-intensive.
SUMMARY OF THE INVENTION
The present invention is based on the object of proving a vehicle detector arrangement for practical everyday use. The inventive vehicle detector arrangement should be capable of acquiring a continuous and durable data base and make it available for evaluation in order to enable dependable traffic information and a traffic routing adapted to the increasing traffic density without having to be connected to an external power supply and to data transmission cables in a complicated way.
For typically achieving the object, the invention proposes that the transmission/reception unit, the energy supply unit and the control unit are accommodated in a housing and are connected to the at least one detector unit, whereby at least one solar cell module is arranged at the outside of the housing.
The inventive vehicle detector arrangement is a compact central unit that can be flexibly utilized, whereby the elements that can be combined for one or more detector elements are accommodated in a housing of, for example, plastic. Such a central unit can be arranged with a supporting structure at buildings, bridges and the like but can also be secured to carrier poles and the like. Due to the energy supply with a solar cell module and the transmission/reception means, the vehicle detector arrangement thus works autonomously and no complicated installation jobs are needed. The connection between the central unit and the at least one detector unit can likewise be mechanically produced with a carrier unit. Detector units can also be positioned completely separately from the housing and can be electrically connected to the central unit.
According to one proposal of the invention, the detector unit—one or more being provided—comprises at least one passive of infrared sensor. Advantageously, the electrical circuit can be such due to the employment of the passive infrared detector that only a minimal power consumption ensues. The at least one sensor element can be arranged in a separate housing, for example a cylindrical housing with a frontal lens cover. According to an especially advantageous proposal of the invention, a detector unit comprises a plurality of sensors, whereby sensors with post-pulse oscillation and sensors without post-pulse oscillation are combined. Advantageously, three sensors with post-pulse oscillation are combined with one sensor without post-pulse oscillation.
According to another advantageous proposal of the invention, the detector unit additionally or alternatively comprises radar sensors or, respectively, additionally or alternatively comprises microwave sensors. A further improvement of the acquisition properties is achieved by the inventive combination of sensors with post-pulse oscillation and without post-pulse oscillation or, respectively, by the use of different sensors.
From the point of view of optimum energy utilization, the invention proposes that the vehicle detector arrangement can be switched between an idle mode and an active mode. This switching ensues automatically, for example after acquisition of a specific minimum number of vehicles, after expiration of an acquisition-free time or the like.
It is advantageously proposed that the solar cell module is adjustable.
Since, in particular, a readjustment of the angle of inclination considerably improves the utilization of solar light, an automatic readjustment of the solar cell module can also be inventively provided.
A critical aspect of the inventive vehicle detector arrangement is an altogether beneficial current balance. A battery and a solar panel are respectively connected to a charge regulator. The battery and charge regulator are designed for a nominal 12 volts. The solar panel, for example, delivers 5 through 6 watts. The charge regulator is connected to a voltage converter that nominally supplies the following detector circuit with 6 volts. Such a circuit enables a power consumption of approximately 4.75 mA at 12 volts. The current balance exhibits a power consumption of a maximum of 36 mW for a detector unit. The dissipated power of the voltage converter lies at approximately 20%, i.e. approximately 9 mW. The charge regulator has an intrinsic consumption that lies at approximately 12 mW. It follows from the data that a buffer battery of only 6.6 Ah can guarantee operation for more than 40 days without current being supplied from the solar panel. The inventive vehicle detector arrangement thus works nearly autonomously and extremely imperceptibly due to the structure. One reason for this is in the PIR technology that is employed, this making use of long-wave infrared radiation that already exists and that every body emits above the absolute zero point (−273° C.).Differing from other technologies, thus, energy need not be emitted and in turn received. Only already existing, natural radiation is received. Radiation contrasts are thereby identified, namely both positive as well as negative contrasts. The ambient temperature thus plays a negligible part because the thermal overall change in radiation is acquired, as a result whereof the detection is nearly independent of the radiation frequency or, respectively, of the wavelength. The radiation contrast, among other things, is a function of the size and of the emission factor of the surface of a vehicle moving in or through the acquisition area. For achieving adequately precise measured values, a wait is first carried out for a temporally stable measured value sequence before the actual measurement.
The principle of a detector unit for achieving the stated objective is based on the detection of a vehicle that moves in a travel direction through a plurality of spatially separate zones that form the acquisition region. These at least two zones derive due to the optical imaging of corresponding sensor elements with a suitable lens arrangement and the evaluation of the resulting sensor signals. The speed information can be acquired from the time that a vehicle requires in order to proceed from zone 1 to zone 2. The vehicle length is calculated from the identified speed and the dwell time of a vehicle in one of the zones. Advantageously, more than the acquired two zones are selected and sensors having post-pulse oscillation as well as sensors without post-pulse oscillation are utilized and the signals resulting therefrom are interpreted in order to be nonetheless able to output information to the control unit given deterioration of a detector function or even given outage of a sensor (thereby providing a redundancy of the measurement).
The intensity and time sequence of the radiation changes produced in this way can vary greatly due to weather conditions over the course of a day and of the year as well as depending on the traffic flow. The amplitudes and time sequences of the signals of each sensor element resulting therefrom are continuously identified and further-processed for control purposes. This control, for example, can influence the properties of the gain of the sensor signals or the response thresholds of the signal processing and is especially advantageous because both the amplifiers as well as the signal evaluation thereby work in an optimum range under al
Büchel Erik
Gabler Manfred
Kuster Walter
Reisinger Elmar
Harness & Dickey & Pierce P.L.C.
Lieu Julie
Siemens Aktiengesellschaft
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