A DEVICE FOR DETECTING AND INFORMATION TRANSFER

Abstract: A device for detection and information transmission comprises a first unit (1) for transmitting and receiving microwaves and shows at least a first antenna (6). It is primarily characterized in that the unit is so arranged that within a first antenna lobe (12, 19) through Doppler shift of a transmitted first microwave signal it detects movements in an object. The unit is further arranged to communicate within a second antenna lobe (7, 13, 20) with a so-called transponder.

Description: A DEVICE FOR DETECTING AND INFORMATION TRANSFER. The present invention relates to a device for detection and information transmission, with a first unit for transmitting and receiving electro¬ magnetic waves within the microwave range, with at least a first antenna. The device is intended to be used for alarm surveillance, admission control and for otherwise affecting limited spaces such as entrances to localities such as public buildings, offices, industrial buildings, private houses, vehicles, particularly cars, etc. Background of the invention It is known to surveille by alarm such limited spaces with the aid of electromagnetic waves. One method uses infrared technique, in which heat sensitive elements are provided with a light intersection device which makes the combination of heat and movement in the surveilled area possible to detect. Another alarm surveillance method uses a radar device which senses the Doppler shift that occurs when a reflecting object is moving in the space in front of the transmission and reception antenna of the device. Both technologies require separate devices for alarm surveillance and admission control/delocking/disarming, which add to costs and lessens reliability in the device. They have also the disadvantage that the disarming of the alarms must be effected without the surveilled space being entered, which can lead to less convenience. A further disadvantage is that domestic animals unintentionally can initiate the alarm. Partilularly the optic alarm equipnent is furthermore difficult to conceil, because its ray path is hindered by opaque material. The risk of sabotage is thereby increased. The object and most important characteristics of the invention The object of the invention is to achieve a device of the kind mentioned in the introduction, for: surveillance and alarm, in buildings and vehicles, surveillance of passages in corridores, etc, admission control, that is locking and unlocking of buildings and vehicles, opening and closing of doors, gates, level crossings etc, acting upon and adjusting, for instance, seats and mirrors in vehicles or rocm selective heat sets in buildings. The device shall be deactivated from contactlessly. Such a device is primarily characterized in that the unit is so arranged that, in a first antenna lobe through Doppler shift of a first microwave signal emitted from the unit it detects existing movement in an object, and, further, is so arranged that, within a second antenna lobe through the transmission of a second microwave signal, it cormrunicates with a second unit in the form of a so-called transponder, so arranged that on receiving said second microwave signal it re-transmits a third, in¬ formation carrying microwave signal, which the first unit is arranged to receive. In an often useful embodiment of the device according to the invention the second antenna lobe, that is the communication lobe, covers however at least partly a space, which is not covered by the first -antenna lobe, that is the detection lobe. There are many cases in which one wishes to separate the detection lobe and the communication lobe more or less completely. ----_,--=---- ^ Within the scope of this invention several embodiments are possible. The first vmit is for example usually so arranged that on detected movement of an object within the first antenna lobe it initiates the giving of an alarm signal. The first unit can be located at the entrance of an industrial plant, private house or the like, said first antenna lobe covering a space within the area nearest to the door. In this antenna lobe, a movement by for instance an unpermitted person can thus be detected and an alarm be initiated, for instance in that an alarm clock is brought to sound. Within a second antenna lobe, which usually covers a space larger than that covered by the first antenna lobe, communication between the first unit and a transponder is possible, whereby the initiating of the giving of an alarm signal can be put out of function by an autho¬ rized person, equipped with a transponder prograi ied in a corresponding way. In an embodiment, particularly suited for application in vehicles, partilularly passenger cars, the device according to the invention comprises at least one second antenna at a distance from the first antenna, so arranged that by transmitting a fourth microwave signal it communicates with a transponder, the second antenna lobe covering a space which is not covered by the first antenna lobe. In this embodiment the first unit can be located inside the vehicle with a first antenna directing a first antenna lobe within the range of the manoevering means of the vehicle, such as ignition lock, gear lever, wheel etc, and valuable objects, such as radio sets, whereas a second antenna connected to the first unit is arranged at a distance from the first unit, either inside the vehicle, for instance at the switch panel at the side of the vehicle or in the internal rear view mirror, or on the outside of the vehicle, for instance in a rear view mirror. In both cases the second antenna transmits a second antenna lobe, in which communication with a transponder is possible, so that the alarm thereby can be turned off by an authorized person. In an embodiment of the device, which can be suitable in closed areas, particularly in a passenger car coupe, the first unit is arranged to be blocked from initiating the giving of an alarm signal if it, through microwave communication with a transponder, receives a corresponding code signal. This embodiment is partilucarly useful if there is a domestic animal in the closed area, such as a passenger car coupe. The domestic animal in question is then provided with the above-mentioned transponder, which prevents the alarm frcm being initiated even if the dαnestic animal is present within the first antenna lobe, in which movements in objects, that is in this case a domestic animal, can be detected. When a breaking into the vehicle is attempted by an unauthorized person it is likely that the domestic animal rapidly either flees frαn the vehicle or in any case moves out of the range of both the first and second antenna lobes, so that the alarm function is automatically activated. The blocking function of the alarm with a transponder can also be of interest for installation in buildings, in that a night guard equipped with a transponder can thereby in a very smooth way temporarily deactivate the alarm while passing the alarmed area. In certain cases it is desired to have a big first antenna lobe, that is a detection lobe, which for instance may be the case when detection of the movements of an object, for instance coning nearer, should call for mechanic movements in units with great inertia, such as an automatic door or road gate. One wishes then to have an early warning that an opening shall take place in order to start the mechanical opening pro¬ cedure, which however is not completed until a permitted transponder cαππunication is completed, for example to debit the correct charge class for a passing vehicle from read transponder data, if it is a question of a road toll or vehicle parking. There may also be a need to have the first antenna lobe, the detection lobe, and the second antenna lobe, the communication lobe, activated at different times, however still using the same first unit and antenna. Also in this case it could be desired that the detection lobe should be even bigger than the cc munication lobe. For instance, at a department store entrance, or in any other often frequented entrance, it may be desired that the door opens for every person that cones into the detection lobe during daytime (when criminality is relatively low) , whereas at night a transponder co-tπtui-ication is necessary for the door to unlock/open up. The detection lobe can then have so great a range that a person caning nearer will not have to slow down on passing during daytime, because of mechanic inertia in the door. During night it is perhaps desired to have a very discreet cαiπtunication lobe in which the transponder ccmmunication in the door opening/door unlocking purpose can occur. In a preferred embodiment of the device the microwave signals emitted frαn the first unit all.show the same frequency, which reduces the manufacturing costs for the equipment and facilitates the obtaining of frequency permission frαn the authorities. Alternatively, it can be advantageous to design the device so that a certain variation in frequency is possible, within the same frequency band, for instance any of the ISM-bands 915 MHz, 2.45 GHz, 5.72 GHz or 24 GHz with a band width of some hundreds of MHz. The use of microwave technique brings advantages such as cαtmunication with good range and insensitivity to filth, snow and ice. Said transponders can be made extremely compact and can thereby be integrated in for example credit cards, wrist watches, boxes and keys. The reason for this is that one prefers to use transponders that do not need to generate any emitted power of their own as their function is achieved through coding and reflection by a radiating microwave signal without any supply of extra energy. In a suitable embodiment of the device according to the invention the first microwave signal is modulated so that the information sideband of the first microwave signal is produced and re-radiated. The antennae can be placed hidden, for example integrated in the switch panel of a vehicle, and in an internal or external rear view mirror, whereby they become difficult to access for sabotage. In a preferred embodiment of the device according to the invention the transponder is so designed, that it comprises a memory, with a first part, which is unique for each individual transponder, which part is not writeable, and a second part, which is writeable by means of a microwave signal. In another embodiment, the second, writeable part of the transponder memory is written with coded information under use of an algorithm: with a coding key, the contents of the not writeable part of the memory and not coded information constitute inputs to the coding process. This embodiment of a transponder is described in more detail in Swedish patent application No. 9301419-9. The device according to the invention can be combined with functions for admission control and unlocking and also for activation an adjustment of the local functions. A great problem with known contactless locking and alarm systems is that they require active handling, typically a button pressing on a unit worn to lock/activate and unlock/deactivate the alarm, usually with alternate function. The device according to the invention admits in a special embodiment with movement detection capability, a considerably simplified handling, in that there are motion detectors which sense every movement in a vehicle coupe as well as in certain cases also a coming nearer/going away function which indicates locking/alarm activation or unlocking/deactivation. The device can accordingly be so designed that its locking function is controlled by an authorized transponder in such a way that the locking function-unlocks when an authorized transponder is coming nearer to the locked object, and locks when an authorized transponder moves away therefrαn. This can take place according to different methods, such as signal processing of quadrature signals and signal processing of the amplitude/time function, respectively. In both cases the first unit is arranged to emit a fifth microwave signal in a second antenna lobe, which covers a space which is not covered by the first antenna lobe, the first unit being arranged, after receiving an emitted information carrying microwave signal frαn a transponder, to signal-process it in order to decide if the transponder is coming closer or is leaving and to emit a corresponding unlocking or locking signal to the locking function. Tfte signal processing can relate to quadrature signals or the amplitude/time function of the signal. The detection of movement and possibly of direction can be effected cor¬ respondingly at an object that is not equipped with a transponder, when after approved ccππtuπication the locking function is acted upon through a movement of the hand, or the like, to open or lock. This function can also be had in the first antenna lobe. The device in vehicles can also be used for adjusting personal drive parameters such as rear view mirror adjustment, seat adjustment, gear shifting points and the like. If the device is mounted in a vehicle it can additionally be combined with information transmission frαn units located along a road. This relates to actively transmitting units which frαn a relatively great distance can transmit information on for example the traffic situation in the road system in question. A number of tran- sponders/tranceivers can also be arranged along a road for transmitting information, such as with regard to current speed limit. It should be observed, that the concepts "first, second etc. microwave signal/antenna lobe" are applied in order to clearly designate the function of the microwave signal/antenna lobe in the case in question. This, of course, does not prevent that it may, per se, be a question of the same frequency/coverage area, but emitted with different level, direction, polarization, information contents etc. Transponders can be designed in many ways, but it is preferred that personally carried transponders are designed alternatively as a thin card, a watch or key or an easily carried box. Description of the examples of embodiment The invention will now be described in more detail with reference to the accompanying figures of which Figure 1 schematically shows the device according to the invention as applied in a passenger car coupe; Figure 2 shows schematically a second antenna, communicating with a transponde; Figure 3 shows schematically the detection of a movement in a first antenna lobe; Figure 4 shows schematically a first antenna in communication with an alarm blocking transponder; whereas Figure 5 shows schematically the device according to the invention as applied at a building entrance; Figure 6 shows schematically the device according to the invention with transponder movement activation which can relate to the locking function in vehicles; Figure 7a shows a diagram for electronics for signal processing of quadra¬ ture signals; Figure 7b shows how the information can be obtained from analyzed quadra¬ ture signals; Figure 8 shows a logic diagram of the device in Figure 6. Information transmission and position/speed indication with the aid of -transponder techniqe, as well as Doppler radar technique, can be effected in a number of ways and therefore shall not be described in more detail here, since they care common knowledge among people skilled in the art. One-way and two-way information transmission with the aid of transponder technique are for example described in U.S. patents 4,242,661, 4,390,880 and 4,075,632. The function of a Doppler radar is described in Skolnik, "Introduction to radar systems". Compact transponder technique, for example to be integrated in watches, credit cards etc, is described in patent (applications) PCT/SE91/00479, 9200209-6 and 9200210-4. The device according to the invention uses one transmitting/receiving unit both for transponder ccmmunication and the Doppler radar function. The means for producing -and transmitting high frequency signal, described in the above-mentioned literature, for example at 2.45 GHz, as for receiving and signal-processing primary radar echoes and information sidebands frαn the transponders are mutual, accordingly, and are based on known technique. They care therefore not mentioned further here. In Figure 1, a passenger car coupe is represented schematically, seen frαn the back seat. A first unit for transmitting and receiving electro¬ magnetic waves within the microwave range is designated by 1, a first antenna, located in the middle of the switch panel by 6, and other antennae 3 connected to the first unit, located in the external rear view mirrors 2 of the vehicle. The first antenna 6 is arranged for both the Doppler radar function -and transponder ccmmunication, whereas the other antennae 2 and 3 are arranged for transponder communication. From Figure 1 it is evident that the first antenna 6 creates a first antenna lobe 12, intended for Doppler radar measuring of movements, and a second antenna lobe 13, for transponder communication. As can be seen, the second antenna lobe 13 comprises the first antenna lobe 12 and extends out of it. These antenna lobes are also shown in Figure 3, where the movements of an unauthorized person in connection with the release of a radio set 15 is demonstrated. This movement is thus intended to be detected within the first antenna lobe 12 for initiating an alarm signal. It is suitable to design the device so that the first antenna lobe 12 will have a relatively limited range, comprising essential means for driving the car, such as ignition lock 16 and objects attractive to thieves, such as radio sets 15, whereas the second antenna lobe 13 has a considerably greater range, suitably comprising the whole vehicle coupe. In Figure 2 a second antenna 2 and its antenna lobe 7 is shown, within which transponder communication for disarming the alarm function, lock opening and possibly transmission of personal drive parameters are possible. The shown person's arm 8 thus carries a transponder in the form of a wrist watch 9 or a credit card 10. In Figure 4 it is shown how a domestic animal, in this case a cat, can be provided with a transponder 17, which by cαmtunication via the first antenna 6 with the first unit within the second antenna lobe 13 blocks the alarm signal frαn being initiated, even if the dαnestic animal moves within the first antenna lobe 12. With the aid of software functions in the first unit 1, time functions can be established which brings about that a blocking of the initiating of an alarm signal, caused by the transponder 17, is interrupted a certain predetermined time after the cαimunication between the transponder 17 and the first unit 1 has ceased, in that the dαnestic animal has moved out of the second antenna lobe 13 by getting down in the back seat or flee out of the vehicle on a burglary whereby a door has been opened. As has already been mentioned the antennae 2 can be used for communication with other units for transmission of information, for example on the -traffic situation, or with transponders or tranceivers according to what is described in SE 9300108 along a road for transmitting information, for example about current speed limit. Parts of the device according to the invention, particularly the antennae 2, can be cαnbined with a mobile telephone in the equipment in the vehicle. Even if application in vehicles is an important application area for devices according to the invention, it can be used with advantage for alarm surveillance of buildings and fenced grounds. So it is shown in Figure 5 an application at an entrance of a building where a first antenna 18 is located hidden in the eaves 22, where a fist antenna lobe 19 for movement detection with Doppler radar is entirely comprised by a second antenna lobe 20 for communication with a transponder. An indicator 21 indicates when the alarm funcrtion is connected, to deter from burglary. It also indicates to a person provided with an authorized transponder, who enters into the second antenna lobe 20, that the alarm function is deactivated through transmission of a corresponding code frαn the transponder in question. In Figure 6 it is shown how an antenna 23, mounted in the internal or external rear view mirror of a passenger car, transmits a second antenna lobe 7, which does not coincide with the first antenna lobe 12, that is the detection lobe, but is directed so that the vehicle locking function is comprised in this second antenna lobe 7. In the figure a person is shown carrying a transponder 9 in the form of a wrist watch. In an embodiment of the device the direction of movement of an object relative to the antenna can be determined by detection circuits in the first unit 1, which is used to further facilitate an unlcxiking/locking function. If a movement of for example a part of the body towards the antenna is detected, at.the same time as a reading/communication of transponder data is effected, it is likely that the lock is desired to be opened, whereas moving away probably means that locking is desired. In Figure 7 there are examples shown on analyses of reflected quadrature signals frc a natural object, for example a part of the body. A local oscillator 25 produces the carrier wave frequency that is used both for transponder communication and Doppler measurment. The carrier wave is guided via a circulator 26 out through an antenna 27. The carrier wave is reflected by different objects 28 back to the antenna 27. The reflected signal is guided frαn the antenna 27 via the circulator 26 to a mixer 28, where the signal is mixed with the local oscillator signal in such a way that two mixed signals appear, so-called I and Q signals, one of which is quadrature shifted relative to the other. The signals are low-pass filtered in the filter 29 in order to reduce the background noise and thereby increase the range of the device. The limiting frequency can for example be sane two hundred kHz to let through information signals from transponders modulated with data at a data rate in the 100 kHz range. The signals are led to the block 30 which comprises transponder commu¬ nication circuits for decoding the received data, partly to a band pass filter 31 for Doppler filtering of the reflections from natural objects, for example a part of the body, that moves in the antenna lobe. The block 30 can also comprise circuits for specific detection of a transponder movement in the -antenna lobe. The frequency range of the bandpass filter 31 is chosen with regard to the speed range in which a movement shall be detected, and can for example be 0.5 Hz to 200 Hz. After the bandpass filter, to the extent an object moves in front of the antenna 27, a low-frequency Doppler signal is obtained where the frequency is proportional to the speed of the object and where the amplitude is proportional to the amount of reflected power. The phase difference between the quadrature signals will be positive or negative depending on whether the object is coming nearer to or is leaving the antenna 27. The signals are amplified to a suitable level in the amplifier 32 and can then be A/D converted and analysed in the movement detector block 33. In Figure 7b an example is shown how information can be obtained frαn the analysed quadrature signals 34 and 35. Through FFT analyses, frequences 36 which the signals comprise can be obtained, and thereby the speed of the object that is moving. By also comparing the signals 34 and 35 with respect to their mutual phase positions, information is obtained on whether the object is coming nearer or is leaving. The amplitude 37 also can be analysed in a time sequence, and thereby give further information on the object -and its possible movement. A special embcxliment of the device according to the inveniton can also determine the specific movement direction relative to the antenna of a transponder, and depending on whether the transponder 9 is brought nearer or taken further away within the -antenna lobe 7 relative to the antenna, electronic circuits included in the first unit 1 will signal process the information carrying microwave signal reflected from the transponder 9, so that the first unit 1 can transmit an unlocking or locking signal to the locking function 24, depending on whether the transponder 9 is brought nearer or taken further away frαn the antenna lobe. In case a detection of a transponder movement shall be effec±ed, the transponder signals that reach the block 30 are detected. In case the transponder is located relatively close to the antenna, getting nearer or further away can easily be determined in that a time sequence with the amplitude values of the signals are taken in and measured with respect to increase or decrease. In the event the transponder is located at a relatively great distance frαn the .antenna, and its relative signal power variation on movement within the locking area therefore is relatively small, qudrature measure- ment can be effected also on the I and Q signals of the transponder in analogy with what has been described concerning movement direction detection of natural objects. Because the information carrying transponder signal is modulated with a inoculation frequency, for example in the 100 kHz range, it can here be suitable to effect one additional mixing of this signal to base band by making it beat against a coherent oscillator (not shown) , likewise working in the 100 kHz range, in the block 30, before the quadrature mearurement is effected. In this way the phase changes of the transponder information signals that are due to movement, are transposed to such low frequences that the A/D converter and signal processing circuits similar to those earlier described for the block 33 can be used. In Figure 8 a logic diagram is represented for this embodiment of the device according to the invention. This diagram is general and is intended also for passage/alarm in buildings. Here follows a brief description of application to a vehicle. Firstly, admission to the vehicle is designated. The driver moves towards the vehicle, whereby the transponder signal is read in a ccmmunication lobe and is found to be authorized for admission. If not (not OK) an earlier initiated alarm detection, that there is no movement in the detection lobe, continues. When the transponder has been found authorized, that is OK, and the vehicle is found locked, the device determines if the transponder has gotten nearer in order that unlocking shall take place. Has this occurred, at the same time as other possible conditions for unlocking (could be time limitations, blocking of function when ignition is on etc) are found to be fulfilled, the alarm detecti o n is deactivated and the device takes the actions that are foreseen, for example automatic adjustment of seat and mirrors. Immediately thereafter the door is unlocked, so that the driver will have time (for example 1 second) to open the door. In this way, it is prevented that the door unintentionally is locked again before it has been opened. The procedure on leaving the vehicle is as follows. After having gotten out of the vehicle the transponder is again read and found to be OK. The device senses that the door is unlocked, and whether leaving takes place in the ccmmunication lobe. If, in addition, the locking conditions care fulfilled, for example that the ignition is not left on, and it is quiet in the coupe (that is in the detection lobe) , the door is locked and the alarm is activated. If the ccimmunication lobe is arranged so that unintentional transponder ccmmunication can occur, for example if the ccmmunication antenna of the device is located in an internal rear view mirror for coπmunication through a side window and the driver happens to hold up his transponder in the cx-mmunication lobe inside the vehicle, locks and alarm should not be affected. This occurs, in that it is a condition for the detection function that it is quiet in the detection lobe, before locking can take place, that is the driver and passengers are not in the vehicle. The above-described device is entirely autonαnous, and although no active button pressings are needed, still it provides a comfortable and complete alarm/admission function.

Claims: Claims 1. A device for detection and information transmission, with a first unit (1) for transmitting and receiving electrαnagnetic way-es. within the microwave range with at least a first antenna (6) c h a c r a c t e r i z e d in that the unit is arranged within a first antenna lobe (12, 19) through Doppler shift of a first microwave signal emitted frαn the unit to detect possible movement in an object, and further is arranged within a second antenna lobe (7, 13, 20) through emitting a second microwave signal to communicate with a second unit in the form of a so-called transponder (9, 10) arranged so that on receiving said second microwave signal it,re-emits a third, information carrying microwave signal, which the first unit is arranged to receive. 2. A device according to claim 1, c h a r a c t e r i z e d in that the second antenna lobe (7, 13, 20) at least partly covers a volume, which is not covered by the first antenna lobe (12, 19) . 3. A device according to claim 1 or 2, c h a r a c t e r i z e d in that at a distance from the first antenna (6) , it comprises at least a second antenna (2, 3) , arranged to communicate with a transponder (9, 20) through emitting a fourth microwave signal. 4. A device according to any one of claims 1 to 3, c h a r a c t e r i z e d in that at least one antenna (3, 6) is integrated in the internal and/or external mirror of a passenger car coupe, alternatively in its switch panel. 5. A device according to any one of claims 1 to 4 ch a r a c t e r i z e d in that the microwave signals emitted frαn the first unit (1) have the same frequency and/or are comprised within the same frequency band, such as one of the ISM bands 915 MHz, 2.45 GHz, 5.72 GHz or 24 GHz. 6. A device according to any one of claims 1 to 5 c h a r a c t e r i z e d in that said transponder (9, 10) is arranged to re-emit the third microwave signal without supplying any energy frαn the transponder. 7. A device according to any one of the preceding claims, c h ar a c t e r i z e d in that at least one transponder (9, 10) comprises a memory, with a first part, which is unique for every individual transponder, which part is not writeable, and a second part which is writeable by means of microwave signal. 8. A d vi-TS according to claim 7, char a cte r i z ed in that he second, writable part of the transponder memory is written with ceded information under use of an --.^algorithm with a coding key, the contents of the not writable part and not coded information of the memory constituting inputs to the coding process. 9. A device according to any one of claims 1 to 8 c h ar a c t e r i z e d in that the first unit (1) is so arranged that on the detection of movement in an object within the first -antenna lobe (12, 19) it initiates an activity such as the giving of an alarm signal. 10. A device according to claim 9, c hara c te r i z ed in that the first unit (1) is blocked from initiating an activity such as an alarm signal, if it through microwave cαmtunication with a second transponder (9, 10, 17) receives a corresponding code signal. 11. A device according to any one of claims 1 to 10, c h a r a c t e r i z e d in that the first unit (1) is arranged to transmit a fifth microwave signal within a second antenna lobe, which covers a space, which is not covered by the first antenna lobe, the first unit (1) being arranged so that on the reception and possible approval of an information carrying microwave signal transmitted frαn a transponder, and furthermore through Doppler signal processing of signals reflected from a movable object, for example a part of the body, it determines with quadrature technique if the object is coming nearer or is leaving, and thereafter gives a corresponding, unlocking/opening or locking/ closing signal to a locking/opening function. 12. A device according to any one of claims 1 to 10, c h a r a c t e r i z e d in that the first unit (1) is arranged to transmit a fifth microwave signal within a second antenna lobe, which covers a space that is not covered by the first antenna lobe, the first unit (1) being so arranged that on the reception and possible approval of an information carrying microwave signal transmitted from a transponder, and furthermore through signal-processing of the amplitude/time funcrtion of reflected signals of a movable object, such as a part of the body, it also determinesif the object is coming nearer or is leaving and emits a corresponding unlocking/opening or locking/closing signal to a locking/opening funcrtion. 13. A device according to any one of claims 1 to 10, c h a r a c t e r i z e d in that the first unit (1) is arranged to transmit a fifth microwave signal within a second antenna lobe (7) which covers a space that is not covered by the first antenna lobe (12), the first unit (1) being so arranged, that on the reception of an information carrying microwave signal emitted frcm a transponder (9, 10) through signal processing of its answer signal mixed to quadrature signals, it determines if the transponder is caning nearer or is leaving, and emits a corresponding unlocking or locking signal to a locking function. 14. A device according to any one of claims 1 to 11, c h a r a c t e r i z e d in that the first unit (1) is arranged to transmit a fifth microwave signal within a second antenna lobe (7) which covers a space that is not covered by the first antenna lobe (12), the first unit (1) being so arranged that on the reception of an information carrying microwave signal emitted frαn a transponder (9, 10) , it determines through signal-processing of the amplitude/time function of its answer signal if the transponder is coming nearer or is leaving and emits a corre¬ sponding unlocking or locking signal to a locking function. 15. A device according to any one of claims 1 to 14, c h a r a c t e r i z e d in that the transponder 9, 10) is personally carried and is designed as a thin card, a watch, key or an easily carried box. 16. A device according to any one of claims 1 to 15, char a ct e r i z ed in that the first unit (1) is arranged to initiate an automatic adjustment of seats and mirrors with the aid of the code that is in the trans¬ ponder (9, 10). 17. A device according to any one of the preceding claims, for a vehicle ch a r a c ter i z ed in that it is arranged to cαππunicate with road side equipment in the form of transponders or tranceivers.

Inventors: GUNNARSSON STAFFAN, GUNNARSSON, STAFFAN
Applicants: GUNNARSSON STAFFAN, SAAB SCANIA COMBITECH AB, SAAB-SCANIA COMBITECH AKTIEBOLAG
Application year: 1993
Main classification: G08B13
IPC codes: G01S13, G06K7, G06K19, G07B15, G08B13, H01Q1