(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2003/0008675 A1
`Willats et al.
`(43) Pub. Date:
`Jan. 9, 2003
`
`US 20030008675A1
`
`(54) SCANNING DEVICE
`
`(30)
`
`Foreign Application Priority Data
`
`(76)
`
`Inventors: Robin Willats, Preston (GB); John
`Emson, West Midlands (GB); Sidney
`Fisher, West Midlands (GB);
`Gurbinder Kalsi, West Midlands (GB);
`Nigel Spun.’ sohhuu (GB); Jean
`Didier,Anou1d (FR); Alan Dixon,
`Chester
`Stephen Drysdale,
`Northampton (GB)
`
`Correspondence Address:
`CARLSON, GASKEY & OLDS, RC.
`400 WEgT MApLE ROAD
`SUITE 350
`BIRMINGHAM, Ml 43009 (US)
`
`(21) App], No;
`
`10/131,604
`
`(22)
`
`Filed:
`
`Apr. 24, 2002
`
`May 4, 2001
`
`(GB) ................................. .. GB0110976.8
`
`Publication Classification
`
`Int. Cl.7 .............................. H04B 1/16; H04B 7/00;
`H040 7/20; H04“ ‘/00; H04B 1/38
`......................... ..
`
`UISI C].
`
`ABSTRACT
`
`(51)
`
`(57)
`
`Ascanning device (12) for use in periodically scanning for
`the existence of at least one corresponding remote response
`device (22) wherein, in use, the rate at which the scanning
`device scans for the response device decreases as the time
`since the detection of a previous response device increases,
`such that the rate of power consumption of the scanning
`device reduces during periods of non-use.
`
`RES PaMS E
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`ASSA 100
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`ASSA 1006
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`Patent Application Publication
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`Jan. 9, 2003 Sheet 1 of 2
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`US 2003/0008675 A1
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`2
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`Patent Application Publication
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`maJ
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`1A5768W
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`

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`US 2003/0008675 A1
`
`Jan. 9, 2003
`
`SCANNING DEVICE
`
`This application claims priority to United Kingdom
`(GB) Patent Application No. 0110976.8 filed on
`May 4, 2001.
`
`BACKGROUND OF THE INVENTION
`
`[0001] The present invention relates to a scanning device.
`More particularly, the present invention relates to a scanning
`device for use in vehicle access control systems,
`for
`example, which periodically scans for the existence of
`associated remote response devices.
`
`[0002] As an alternative to the use of a key or remote ‘plip’
`type devices for gaining access to a vehicle and/or starting
`the engine of a vehicle once inside, it is known to provide
`a scanning device that is associated with the vehicle and
`which scans for the existence of response devices within a
`given range by using radio frequency waves, for example.
`Only if a code held by the response device matches an access
`code held by the scanning device will access to the vehicle
`be permitted.
`
`From the point of view of the vehicle user, it is
`[0003]
`desirable that
`the rate of scanning by such devices is
`relatively high so that the user does not have to wait for a
`relatively long period of a time before being able to enter the
`vehicle. However, the higher the scan rate, the greater the
`rate at which power is consumed by the scanning device.
`
`[0004] The power available from either the vehicle battery
`or a dedicated power source for the scanning device is
`effectively finite when there is no other source such as a
`running engine to charge the battery/power source. Thus, if
`a vehicle having such a scanning device is left for an
`extended period of time whilst operating at a high scanning
`frequency, the power source may be exhausted which makes
`entry into the vehicle difficult and/or prevents the starting of
`the vehicle.
`
`SUMMARY OF THE INVENTION
`
`[0005] The present invention seeks to overcome or at least
`mitigate the problems of the prior art.
`
`[0006] According to one aspect of the present invention
`there is provided a scanning device for use in periodically
`scanning for the existence of at least one corresponding
`remote response device wherein, in use, the rate at which the
`scanning device scans for the response device decreases as
`the time since the detection of a previous response device
`increases, such that the rate of power consumption of the
`scanning device reduces over prolonged periods of non-use.
`
`[0007] According to another aspect of the present inven-
`tion there is provided a method of scanning for the existence
`of at least one corresponding remote response device com-
`prising the steps of:
`[0008]
`i) providing a scanning device operating at a
`first scanning rate;
`[0009]
`ii) reducing the scanning rate of the scanning
`device as the time lapsed since a previous detection
`of a response device increases.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0010] The various features and advantages of this inven-
`tion will become apparent to those skilled in the art from the
`
`following detailed description of the currently preferred
`embodiment. The drawings that accompany the detailed
`description can be briefly described as follows:
`
`[0011] FIG. 1 is a schematic diagram of an access control
`system for a vehicle incorporating a scanning device accord-
`ing to one embodiment of the present invention.
`
`[0012] FIG. 2 is a graph illustrating the relationship
`between the scan rate periodicity and the time elapsed since
`the last detection of a response device by the scanning
`device of FIG. 1.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`
`[0013] Referring to FIG. 1 there is indicated generally at
`10 an access control system for a vehicle 8. In this version,
`the system 10 incorporates a scanning device 12 comprising
`a controller 14 (preferably a microprocessor), a scanning
`sensor 16 and a dedicated power source 20 such as a
`rechargeable battery. The scanning device 12 in this embodi-
`ment is also supplied with power by an external power
`source 24 such as the vehicle battery.
`
`[0014] The scanning sensor 16 is capable of communicat-
`ing with one or more associated response devices 22 using
`radio frequency waves, for example. Outputs from the
`controller 14 are connected to one or more door latches 26
`
`the engine starter 28. A
`as well as, in this embodiment,
`switch 30 is preferably provided between the controller
`output and the starter 28 such that the driver of the vehicle
`may close the switch to start
`the engine only once an
`appropriate output signal is received from controller 14. In
`this way, the scanning device may act as an engine immo-
`bilizer.
`
`In use, authorized users of the vehicle carry the
`[0015]
`response device 22 which preferably takes the form of a
`transponder having an identifier code stored therein. The
`scanning sensor 16 periodically scans for the existence of
`such response devices 22 within its range of operation under
`the control of controller 14 and when such a response device
`22 is detected,
`the scanning sensor 16 interrogates the
`response device to obtain the identifier code which is then
`passed to the controller 14 so that it may be authenticated
`against codes held within a memory associated with the
`controller 14. If there is a match, the controller then sends a
`signal instructing the unlatching of door latches 26, and the
`authorizing of the starting of the engine starter. Once the
`user is seated in the vehicle, switch 30 may be closed to start
`the vehicle engine.
`
`In normal use, the scanning device 12 preferably
`[0016]
`draws its power from the external power source 24 and the
`controller ensures that dedicated power source 20 is fully
`charged from the external power source 24 (e.g., a battery of
`the vehicle to which the device is fitted). However, during
`long term parking, when the vehicle is not being used, the
`external power source 24 may become exhausted. In such
`circumstances, the controller 14 senses when the external
`power source falls below a predetermined certain level of
`charge and instead draws power from the dedicated power
`source 20 (e.g., a battery associated with the device), in
`order to prolong the period during which the vehicle may be
`accessed beyond the point at which the external power
`source becomes exhausted.
`
`4
`
`

`
`US 2003/0008675 A1
`
`Jan. 9, 2003
`
`[0017] Because vehicle users wish to gain access to the
`vehicle rapidly, the scanning rate (frequency) is normally set
`relatively high at, say, two second intervals (0.5 Hz). How-
`ever, at this scanning rate, the external power source 24 and
`in particular the dedicated power source 20, become rapidly
`exhausted during a long period of non-use.
`
`[0018] Therefore, the scanning device 12 of the present
`invention reduces the scan rate dependent upon the time
`elapsed since a response device was previously detected. In
`some classes of embodiment, the scan rate reduction may be
`in direct proportion to the time elapsed or may reduce
`exponentially, logarithmically or in accordance with another
`suitable mathematical relationship. However,
`in preferred
`embodiments, the scan rate reduces in a ‘stepped’ manner.
`The reduction may be a single step or multiple steps.
`
`[0019] Referring now to FIG. 2, a graph illustrating a
`notional example of such variable scan rate is shown. The
`scan rate, elapsed times and number of reduction steps may,
`of course, be altered according to particular user require-
`ments. It can be seen from FIG. 2 that for an initial period
`of one day since the last response device was detected, the
`scan rate is once every two seconds (in order to allow for a
`rapid response to the approach of a potential vehicle user
`when the vehicle is merely left overnight, for example).
`Beyond one day,
`the rate then drops to once every ten
`seconds (0.1 Hz) to allow for a slightly less rapid response
`when the vehicle is left for a longer period, such as airport
`parking, for example. This rate reduction results in a reduc-
`tion in power consumption that potentially extends the life
`of the power source by five tin1es in comparison with the two
`second scan rate.
`
`[0020] After seven days of non-use, which could in prac-
`tical terms represent the vehicle being left for sale with a
`dealer, or in winter layup, the scan rate reduces to once every
`thirty second (0.033 Hz), thereby potentially increasing the
`battery life fifteen fold with respect
`to the two second
`interval scan rate.
`
`[0021] Clearly, such a response delay would be unaccept-
`able in day to day use, but would not present a problem when
`the vehicle is to be operated for the first time after a long
`period of non-use.
`
`In order to determine the time elapsed since the last
`[0022]
`detection of a response device, a time logging device such
`as an in-built quartz timer and counter (not shown) are
`advantageously incorporated into the controller 14.
`
`It should be understood that numerous changes
`[0023]
`may be made within the scope of the present invention. For
`example, alternative types of scanner using other forms of
`electromagnetic radiation such as microwave, or infra-red,
`may be employed, as may sonar scanners. The controller
`may also output to actuators and the like for adjusting the
`seating, steering wheel and mirror positions, for example, in
`order to personalize the vehicle settings for a particular user
`carrying a response device. Furthermore, the controller may
`be incorporated into the overall vehicle control system rather
`than being part of the stand-alone scanning device. It is
`envisaged that the scanning device may be used in other
`fields such as building access control, for example.
`
`aforementioned description is exemplary
`[0024] The
`rather that limiting. Many modifications and variations of
`
`the present invention are possible in light of the above
`teachings. The preferred embodiments of this invention have
`been disclosed. However, one of ordinary skill in the art
`would recognize that certain modifications would come
`within the scope of this invention. Hence, within the scope
`of the appended claims,
`the invention may be practiced
`otherwise than as specifically described. For this reason the
`following claims should be studied to determine the true
`scope and content of this invention.
`
`1. A scanning device for use in periodically scanning for
`the existence of at least one corresponding remote response
`device wherein the rate at which the scanning device scans
`for the response device decreases as the time since the
`detection of a previous response device increases, such that
`the rate of power consumption of the scanning device
`reduces during periods of non-use.
`2. Ascanning device according to claim 1 suitable for use
`in an access control system.
`3. Ascanning device according to claim 1 suitable for use
`in an engine immobilizer.
`4. A scanning device according to claim 1 wherein the
`scanning device is associated with a vehicle.
`5. A scanning device according to claim 1 wherein the
`device scans using electromagnetic radiation.
`6. A scanning device according to claim 1 wherein the
`device is powered by a remote power source associated with
`the vehicle.
`
`7. A scanning device according to claim 1 wherein the
`device is powered by a dedicated power source associated
`with the device.
`
`8. A scanning device according to claim 7 wherein the
`dedicated power source provides a back-up to remote
`vehicle power source.
`9. A scanning device according to claim 8 wherein the
`dedicated power source supplies power to the scanning
`device once the power stored by the remote power source
`falls below a predetermined level.
`10. A scanning device according to claim 1 wherein the
`decrease in the scan rate is at least single step.
`11. An access control system, comprising:
`
`a scanning device:
`
`a remote response device; and
`
`a security device wherein the scanning device scans for a
`security code that unlocks the security device,
`the
`security code held by the response device, wherein the
`rate at which the scanning device scans for the response
`device decreases as the time since the detection of a
`
`previous response device increases.
`12. Amethod of scanning for the existence of at least one
`corresponding remote response device comprising the steps
`of:
`
`providing a scanning device operating at a first scanning
`rate; and
`
`reducing the scanning rate of the scanning device as the
`time lapsed since a previous detection of a response
`device increases.
`
`5