EP1221152B1

EP1221152B1 - Electronic presence surveillance

Info

Publication number: EP1221152B1
Application number: EP99947388A
Authority: EP
Inventors: Pascal Feuillarade
Original assignee: Feuillarade Pascal
Current assignee: Feuillarade Pascal
Priority date: 1999-09-20
Filing date: 1999-09-20
Publication date: 2003-05-07
Anticipated expiration: 2019-09-20
Also published as: AU6085799A; EP1221152A1; WO2001022379A1; ATE239960T1; DE69907760D1

Abstract

A presence surveillance system for surveilling the presence of a mobile object within a predetermined distance range of up to a plurality of 10 metres, comprising an R.F. transmitter emitting R.F. signals and being attacheable to said mobile object and an electronic monitoring device for receiving and processing said R.F. signals for determining the momentary actual distances of said R.F. transmitter with respect to said monitoring device, the monitoring device correspondingly comprising a receiver section being adapted to said R.F. transmitter, a distance measuring section determining the actual distance and providing a distance output signal corresponding to the determined actual distance and being connected to said receiver section, and a microprocessor section, wherein the receiver section and the measuring section are controlled by the microprocessor section, wherein the monitoring device is incorporated into a mobile phone apparatus such as especially a GSM cellular phone apparatus comprising a dice comprising a CPU, with a transceiver, a keyboard and a display being connected to the CPU, wherein at least the microprocessor section of the monitoring device is integrated into the CPU of the mobile phone apparatus and the monitoring device is operatively connected to the keyboard and the display of the mobile phone apparatus.

Description

The present invention relates to electronic surveillance systems for surveilling the presence of a mobile object within a certain distance with respect to a monitoring device surveilling the mobile object. Such a system generally consists of primarily a transmitter, a receiver and a processing unit for processing the data or signals from the transmitter and received by the receiver. The invention especially relates to such systems which further release an alarm, when a threshold distance between the mobile object and the monitoring device is exceeded, and which are able to determine and indicate the direction of the mobile object with respect to the monitoring unit.
Hawthorne (U.S. Pat. No. 4,785,291) discloses a system for determining and indicating the distance between a transmitter and a receiver (monitor), in which the signal indicated on the receiver turns into an alarm mode signal, as soon as a threshold distance is exceeded by the transmitter. This system is not able to monitor the direction of the transmitter. The receiver (monitoring device) is a box intended for stationary use.
Perez et al. (U.S. Pat. No. 5,289,163) and Musa (U.S. Pat. No. 5,557,259) suggest locating systems for surveilling the distance and the direction of a transmitter in reference to a receiver by releasing an audible and/or vibrating alarm and displaying the direction of the transmitter on the receiver as soon as a threshold distance is exceeded by the transmitter. In Perez et al. the monitoring device is a box, attacheable to a person. In Musa the monitoring device has the form of a bracelet, attacheable to the wrist of a person.
Dalsace (Fr. Pat. App. No. 2,749,994) suggests a transmitter-receiver system for releasing an audible or vibrating alarm, when a selectable predetermined threshold distance is exceeded. This system does not provide a direction monitoring option.
Recently, Pearl (www.pearl.com) has revealed a surveillance system, wherein the distance and the direction between a monitor box and an element attacheable to the person to be surveilled (e.g. a child) may be displayed on an LCD display. This system does not provide an alarm option for releasing an alarm when a preset threshold distance is exceeded.
A system measuring and displaying the distance, and releasing an alarm if a threshold distance is exceeded, is known from US-A-5 661 460. This system, however, does not disclose that the distance measuring unit is incorporated into a mobile phone, sharing the CPU of the mobile phone.
It is the intention of the present invention to provide a compact, portable surveillance system for surveilling the presence of a mobile object within a predetermined distance range of up to typically several 10 metres with respect to a monitoring device. Such a system is a useful instrument e.g. for an adult having the charge of a playing child. She/he can attach the mobile object to the child and have the monitoring device with her/him, and thus she/he can surveille the presence of the child without the need of permanent direct visual or mechanical contact to the child, which would prevent her/him from doing other things during her/his activity of surveilling the child. The surveillance system can also be used for other applications, such as monitoring the distance of elderly or mentally disabled people outside specialized homes or clinics, of a team or group member (outdoor sports and leisure activities), a pet or the like.
According to the present invention said monitoring device is incorporated into a mobile phone apparatus such as e.g. a GSM cellular phone. Due to this latter feature the surveillance system of the invention is especially comfortable for users: mobile phones are very common by now, thus it is not unusual that a person owns a private mobile phone and permanently has this phone with her. This means that when whishing to use the surveillance system the person does not have to take an additional, bulky device with her, but she can just use a supplementary option of her mobile phone, which she has with her anyway.
The presence surveillance system according to the present invention comprises on the one hand an R.F. transmitter emitting R.F. signals and being attacheable to a mobile object. On the other hand it comprises an electronic monitoring device comprising a receiver section being adapted to said R.F. transmitter. Said receiver section receives R.F. signals emitted by the R.F. transmitter and provides a corresponding signal to a distance measuring section also provided in the monitoring device. The distance measuring section determines from the received actual R.F. signal more or less permanently at successive time points the corresponding momentary actual distance of the R.F. transmitter with respect to the monitoring device and outputs a corresponding distance output signal to a microprocessor section provided in the monitoring device. Said microprocessor section preferably compares the value of said distance output signal to a threshold value corresponding to a predetermined threshold distance, which should not be exceeded by the mobile object, i.e. for example by the child. The threshold value is for example stored in a memory of the monitoring device being provided therein. If now the value of the distance output signal exceeds said threshold value, an alarm section provided in the monitoring device generates an alarm.
The aforementioned microprocessor further controls the receiver section, the measuring section and the alarm section.
The R.F., i.e. the Radio Frequency spectral range has been chosen, as by using this spectral range transmission with little distortion or interference can be obtained, even with the presence of objects such as walls, doors and vegetation in the transmission path of R.F. signals between the R.F. transmitter and the monitoring device.
The mobile phone apparatus of the invention comprises a dice comprising a CPU, with a transceiver, an alarm unit disposing of one or more alarms such as audible, voice and vibrational alarms, a keyboard and a display being connected to the CPU.
According to the invention at least the microprocessor section of the monitoring device is integrated into the dice of the mobile phone apparatus, the monitoring device is operatively connected to and thus may be operated via the keyboard and the display of the mobile phone apparatus. Preferably the actual distances are recallable into the display of the mobile phone apparatus by means of the keyboard thereof. Optionally, if the mobile phone apparatus disposes of a menu, the aforementioned actions of operating the monitoring device and of recalling the actual distances into the display of the mobile phone apparatus may also be done via said menu.
Although there is the possibility that the monitoring device is provided with a separate alarm section for generating specific alarms, the alarm section of the monitoring device is preferably integrated into the alarm unit of the mobile phone apparatus, and optionally disposes of specific alarms for the electronic surveillance system, which are different from the conventional alarms of the mobile phone.
The actual distance between the R.F. transmitter and the monitoring device may be measured via the signal amplitude of the R.F. signal received by the receiver section of the monitoring device. This method has the disadvantage that, even though an appropriate spectral range has been chosen, objects and obstacles in the transmission path of the R.F. signal can distort the R.F. signal, such that the actual distance is determined incorrectly. Therefore, for measuring the actual distance between the R.F. transmitter and the monitoring device there is preferably provided a pulsed operation mode. In this mode the R.F. transmitter emits as R.F. signals a series of successive R.F. pulses at a corresponding series of successive time points of emission. At least one of the microprocessor section and the receiver section of the monitoring device is synchronized to these time points of emission of said R.F. pulses. For example the R.F. transmitter and the monitoring device comprise each a clock, and the two clocks run at the same speed and emit their respective clock pulses at the same time point or alternatively at two different time points having a specified fixed time distance with respect to each other. The distance measuring section determines the propagation time period of each of the R.F. pulses proceeding between the R.F. transmitter and the monitoring device. From this propagation time period the actual distance between the R.F. transmitter and the monitoring device is determined. The distance measuring section generates a distance output signal corresponding to the propagation time period and thus to the actual distance measured before and provides said distance output signal to the display of the mobile phone apparatus, where the distance output signal is displayed in a form such as "DISTANCE:.....m". Optionally said distance output signal is displayed via a bar graph.
Although the pulsed operation mode is preferably used according to the invention, it would be possible instead that there is provided a monitor transmitter in the monitoring device which is designed such that it emits a switch-on impulse to the mobile object. The switch-on pulse may be emitted when a key of the mobile phone or a button is depressed. The mobile object comprises a transceiver comprising, besides the R.F. transmitter, an object receiver for receiving the switch-on impulse from the monitor transmitter. The transceiver is designed such that receipt of the switch-on impulse switches the R.F. transmitter of the mobile object on and initiates the emission of one or more R.F. signals by the R.F. transmitter.
Optionally the switch-on impulse from the monitor transmitter initiates the emission of the first pulse in pulsed operation mode and the a distance measurement in pulsed operation mode.
According to a further preferred option of the surveillance system according to the invention the direction of the location of the R.F. transmitter with respect to the location of the monitoring device is detected via determination of the polarization of the R.F. signals. The monitoring device for this purpose further comprises a direction detector circuit. For detecting said direction the user e.g. executes a rotation around the vertical axis of his upright body by an angle of 360 degrees. When doing so he also rotates the monitoring device, i.e. the mobile phone apparatus. When, according to the relative orientation of the antenna of the monitoring device and the field vector of the R.F. signal, the receiver signal is e.g. a maximum or e.g. a minimum, corresponding to the fact that the direction of the location of the R.F. transmitter has been found, the alarm section of the monitoring device generates an alarm. The alarm can be an alarm of the mobile phone apparatus or alternatively a separate audible or visible signal such as a beep or an LED. Alternatively or in addition the display indicates that the direction has been found. The direction of the location of the R.F. transmitter with respect to the location of the monitoring device can alternatively be detected via the signal amplitude of the R.F. signal. But this latter method has the disadvantage that objects or obstacles in the transmission path of the R.F. signals possibly distort the transmission of the R.F. signals, which makes it difficult to search and find the direction.
According to another option the predetermined threshold distance is presettable via the keyboard and preferably under support of the display of the mobile phone apparatus or, if available, via the menu of the latter. This setting of the threshold distance can be such that the threshold distance is a permanent preset value. Preferably the threshold distance is settable and changeable by the user of the surveillance system as often as she/he wants, wherein the value of the threshold distance is freely adjustable to be a value not greater than the value of the predetermined distance range of e.g. 50 metres. Further, the monitoring device may even be settable to a plurality of threshold values to respond to a plurality of additional different threshold distances, and the alarm section of the monitoring device generates an alarm each time the value of the distance output signal exceeds one out of the plurality of corresponding additional different threshold values. These additional different threshold values are preferably settable, just like the first threshold value. They may be presettable (once) by the manufacturer, but they are preferably settable by the user as often as she/he wants, with the threshold values being freely adjustable in the same way as for the abovementioned single threshold value. Further, preferably different alarms may be available for the different threshold values. For example a vibrational and/or a visual alarm is generated for all but the largest threshold values, and a beep and optionally a visual alarm is generated for the largest threshold value. Or a pulsed beep is generated for all but the largest threshold values, wherein the pulse repetition rate may be related, e.g. directly proportional, to the respective threshold value, and a permanent beep is generated for the largest threshold value. Or beeps of different frequencies or of different sound volumes are generated for the different threshold values, or the like. Alternatively some other combination of alarms out of the available alarms - comprising the separate ones and the ones of the mobile phone - may be provided.
The surveillance system being intended also for outdoor use, the R.F. transmitter is preferably hermetically sealed into a waterproof casing. Preferably the R.F. transmitter is further incorporated into a bracelet with an adjustable strap, such that the bracelet can be attached to a wrist, arm, ankle, leg, the upper part of the body, the neck or the like of a person. The R.F. transmitter may alternatively be incorporated into a belt, a pendant to be worn on a strap or the like around the neck or the like, or the like.
The presence surveillance system of the invention preferably further disposes of a standby mode. When the surveillance system is in standby mode, the R.F. transmitter emits R.F. signals, the receiver of the monitoring device receives the R.F. signals, the distance measuring section determines the distance between the R.F. transmitter and the monitoring device and provides a distance output signal to the microprocessor section of the monitoring device. The microprocessor section comprises a comparing section being designed such that it then compares the value of the distance output signal to a or, if several threshold values are available, to the several different threshold value/s. When the value of the distance output signal exceeds the or any out of the several different threshold value/s, respectively, an alarm is released, and alternatively also the distance output signal is provided to the display of the mobile phone, such that the distance is displayed on the display of the mobile phone. If a direction detector cercuit is available, as there is in the preferably, upon exceeding of a threshold distance also a direction output signal is provided to the display or to the alarm unit or to both.
In normal operation mode all features of said standby mode are available, and in addition the distance output signal is permanently provided to the display of the mobile phone for being displayed there. I.e. the distance output signal is provided to the display for being displayed there also in that case, when no predetermined threshold value is exceeded.
Summarizing, in standby mode the user is contacted by the monitoring device only in that case, when a predetermined threshold value is exceeded. In that case, when a predetermined threshold value is exceeded, at least an alarm is raised. Preferably the system is switched to normal operation mode as well. In normal operation mode distance and, if a direction detection circuit is available, direction of the R.F. tranmitter with respect to the monitoring device are permanently indicated, wether the distance exceeds a threshold distance or not; when a threshold distance is exceeded, an alarm is raised.
When a predetermined threshold distance is exceeded while the mobile phone apparatus is in use in conventional telephone mode, e.g. while the user is making or receiving a telephone call or while the user is setting the menu or while she/he is checking a mail box of the mobile phone apparatus, if such is available, or the like, at least an alarm is raised. Preferably the surveillance system is in addition automatically switched to normal operation mode, i.e. the distance output signal and optionally the direction output signal is/are provided to the display to be indicated there. Neither said raising of an alarm nor said switching to normal operation mode, when a predetermined threshold distance is exceeded, interrupts the activity of the conventional telephone mode momentarily in use. I.e., for example a telephone conversation is not interrupted, when a threshold distance is exceeded.
Summarizing, the incorporated monitoring device of the invention does not alter the conventional functions of the mobile phone apparatus.
The monitoring device of the invention is preferably incorporated into a cellular mobile phone apparatus, nevertheless it may alternatively be incorporated into the cordless mobile phone apparatus of a conventional cordless phone.
While the features according to the invention are described in the claims, the invention is further described in reference to a preferred embodiment of the invention as shown in the drawings.
Fig. 1 shows a bracelet A with an incorporated R.F. transmitter C according to the invention.
Fig. 2 shows a monitoring device E according to the preferred embodiment of the invention being, according to the invention, incorporated into an mobile phone apparatus APP and a microprocessor section P according to the preferred embodiment of the invention.
Fig. 3 shows an R.F. transmitter C according to the preferred embodiment of the invention.
Fig. 4 shows a monitoring device E according to the preferred embodiment of the invention.
Fig. 5 shows part of a monitoring device E according to another embodiment of the invention.
The description of the preferred embodiment will be made in reference to figures 1 to 4 of the drawings.
The R.F. transmitter C according to the preferred embodiment of the invention is preferably incorporated into a bracelet A, as shown in fig. 1.
Referencing to fig. 2 a monitoring device E according to a preferred embodiment of the invention is incorporated into a mobile phone apparatus (APP). The mobile phone apparatus according to the preferred embodiment of the invention comprises an antenna AN, a display DI, a keyboard KB, and a microprocessor section P, here for clarity shown outside the mobile phone apparatus, but according to the invention being incorporated into the mobile phone apparatus.
With reference to fig. 3 the R.F. transmitter C according to the preferred embodiment of the invention is incorporated into a bracelet A and comprises an antenna B and a lithium cell D. The antenna B is a double line antenna. The encoding is 12 bit and programmable via a switch (not shown). For alimentation a PP3 battery with an output voltage of 9 Volts is used. The frequency of the R.F. transmitter C is 433 MHz. The cycle of emission is 1 emission per second, wherein the emission is optionally visualized via an LED. The range of emission of the R.F. transmitter C is typically 20 metres. The R.F. transmitter C is sealed into a casing made of ABS and having the size of a typical sports wristwatch. A membrane being tightly connected with the casing guarantees the hermetical disconnection of the R.F. transmitter C from the environmental atmosphere. An adjustable strap allows the adjustment of the bracelet to an arm, wrist, upper part of the body, an ankle or the like the bracelet is to be attached to.
With reference to fig. 4 the monitoring device E comprises an antenna F, an alimentation means G, a receiver section H with a direction detector circuit, a distance measuring section I, a threshold adjustment section J for setting the predetermined threshold value or values, a switching means K for switching the monitoring device E between normal operation mode and standby mode, an alarm 1 L and a display 1 M, each of the two latter being related to the measurement of the distance between the R.F. transmitter C and the monitoring device E, an alarm 2 N and a display 2 O, each of the two latter being related to the determination of the direction of the R.F. transmitter C with respect to the monitoring device E, and a microprocessor section P.
The antenna F of the monitoring device E is a SMA-double line joint and at the same time a quarter-wave antenna. The alimentation G is identical with the battery of the mobile phone apparatus. The level of the received R.F. signal is indicated digitally via a bar graph. The receiver section H operates at a frequency of 433 MHz. The encoding is 12 bit and programmable via a switch (not shown).
The microprocessor section P of the monitoring device E consists of a section of a silicon dice comprising a printed circuit. The silicon dice of the preferred embodiment is identical with the dice of the mobile phone apparatus, which dice is modified by the microprocessor section P, the dice of the mobile phone apparatus comprising registers, an arithmetic-logic unit ALU, a control unit, a bus, data input and output interfaces and a line amplifier and disposing of bus adresses indicating the location of data to be read from or to be written into a central memory.
For fullfilling the functions of the surveillance system, which are supplementary to the conventional functions of a mobile phone apparatus, a microprogram is integrated into the microprocessor section P.
The complete dice thus treats the four functions of:

operating in the conventional mobile phone net,
permanently transmitting, processing and maintaining information coming from the R.F. transmitter C towards the mobile phone apparatus,
utilizing the release means of the existing audible, voice or vibrational alarms of the mobile phone apparatus, when a predetermined threshold distance between the R.F. transmitter C and the receiver H (the mobile phone apparatus) is exceeded, and
indicating the direction of the R.F. transmitter C on the display and/or via an alarm of the mobile phone apparatus via the magnetic pole of the R.F. transmitter C (or an analogous system).

The microprocessor section P calculates in real time the propagation time period of R.F. signals from the R.F. transmitter C to the mobile phone apparatus. This calculation allows the indication of the exact distance of the location of the R.F. transmitter C with respect to the location of the mobile phone apparatus on the display DI of the mobile phone apparatus.
The detailed functioning of the monitoring device E according to the preferred embodiment of the invention in its function of detecting an actual distance being larger than a threshold distance is the following.
The R.F. receiver H receives an R.F. signal and transmits the R.F. signal to the distance measuring section I. The threshold adjustment section J releases via the distance measuring section I the activation of the alarm 1 L and the display 1 M. Then the alarm 1 L releases the alarm 2 N and the display 2 O. The alarm 2 N and the display 2 O are repeated until manual extinction.
The alarm 1 L and the display 1 M are repeated until the threshold distance J is not exceeded any more (optional manual extinction).
The surveillance system of the preferred embodiment of the invention disposes of four threshold distances, which are settable in the threshold adjustment section J and via the menu or generally via the keyboard KB and the display DI of the mobile phone apparatus to be e.g. 5, 10, 15 and 20 metres.
In standby mode an alarm 1 L is released when one out of the four predetermined threshold distances is exceeded. When exceeding 5 metres, a beep with a duration of 0.5 seconds is emitted every 4 seconds, when exceeding 10 metres said beep is emitted every 2 seconds, when exceeding 15 metres, said beep is emitted every one second, and finally when 20 metres are exceeded, a permanent beep is emitted, and the system is switched to normal operation mode. The alarm 1 L triggers the display 1 M, which in turn releases the alarm 2 N and the display 2 O. Said beep is preferably an audible alarm of the mobile phone.
In normal operation mode the receiver H and/or the distance measuring section I activate/s the display 1 M, which in turn releases the alarm 2 N and the display 2 O.
The alarm 2 N and the display 2 O are repeated until manual extinction.
The display 1 N can e.g. be a text such as "DISTANCE:....m" displayed on the display of the mobile telephone.
The display 2 O can be a text such as "Direction OK", when the direction of the location of the R.F. transmitter C is found, and a text such as "Searching Transmitter" otherwise.
In normal operation mode, the display of the mobile telephone e.g. alternately displays the texts of display 1 N and display 2 O, each of the texts staying on the display for e.g. one second, or, according to the choice by the user, the display 1 N permanently stays visible on the display, until manual extinction.
According to another embodiment of the invention the predetermined distance range is typically 100 metres. According to still another embodiment said range is a few or several 10 metres or a plurality of 10 metres.
The monitoring device of the surveillance system according to the present invention is preferably incorporated into a cellular mobile phone apparatus, but it may alternatively also be incorporated into a conventional cordless phone with a cordless mobile phone apparatus (APP) as shown in fig. 2 and a cordless phone base station (BST) as shown in fig. 5.

Legend to Drawings

Figure 3
A - bracelet
B - antenna
C - transmitter radio frequency
D - alimentation, lithium cell
Figure 4
E - monitoring device
F - antenna
G - alimentation
H - receiver, direction detector
I - distance measuring section
J - threshold adjustment section
K - switching means
L - alarm 1
M - display 1
N - Alarm 2
O - display 2
P - microprocessor

Claims

A presence surveillance system for surveilling the presence of a mobile object within a predetermined distance range of up to a plurality of 10 metres, comprising
an R.F. transmitter (A) emitting R.F. signals and being attacheable to said mobile object, and
an electronic monitoring device (E) for receiving and processing said R.F. signals for determining the momentary actual distances of said R.F. transmitter with respect to said monitoring device, the monitoring device correspondingly comprising

a receiver section being adapted to said R.F. transmitter,

a distance measuring section determining the actual distance and providing a distance output signal corresponding to the determined actual distance and being connected to said receiver section, and

a microprocessor section,

wherein the receiver section and the measuring section are controlled by the microprocessor section,

wherein the monitoring device is incorporated into a mobile phone apparatus (APP) such as especially a GSM cellular phone apparatus comprising a dice comprising a CPU, with a transceiver, a keyboard and a display being connected to the CPU,
wherein at least the microprocessor section of the monitoring device is integrated into the CPU of the mobile phone apparatus and the monitoring device is operatively connected to the keyboard and the display of the mobile phone apparatus.
A presence surveillance system according to claim 1,
wherein further
said microprocessor section comprises a comparing section for comparing the value of said distance output signal to a threshold value corresponding to a predetermined threshold distance, and
the monitoring device comprises an alarm section being connected to at least one out of said distance measuring section and said microprocessor section and being controlled by said microprocessor section and generating an alarm, when the value of said distance output signal exceeds said threshold value.
A presence surveillance system according to claim 2,
wherein further
the mobile phone apparatus comprises an alarm unit disposing of one or more alarms such as especially audible, voice and vibrational alarms, and
the alarm section of the monitoring device is integrated into the alarm unit of the mobile phone apparatus.
A presence surveillance system according to any of claims 1 to 3, wherein the mobile phone apparatus further comprises a menu circuit and a menu program unit operating the menu circuit, the monitoring device being operated and controlled via said menu program unit, and the actual distances being recallable into the display of the mobile phone apparatus by means of the menu program unit thereof.
A presence surveillance system according to any of claims 1 to 4, wherein the R.F. transmitter is designed such that it emits as R.F. signals a series of successive R.F. pulses with a predetermined pulse period and a predetermined pulse length at a corresponding series of successive time points of emission in a pulsed operation mode,
at least one of the microprocessor section and the receiver section of the monitoring device being synchronized to the time points of emission of said R.F. pulses with a time delay of zero or not zero with respect to said time points,
the distance measuring section of the monitoring device being designed to determine the propagation time period of each of the R.F. pulses proceeding between the R.F. transmitter and the monitoring device,
the distance measuring section for each R.F. pulse generating a distance output signal corresponding to the respective propagation time period of the respective R.F. pulse and thus to the actual distance between the R.F. transmitter and the monitoring device, and
the distance output signal being displayed on the display of the mobile phone apparatus, optionally together with a text such as "Distance: <...> m", wherein at the place of the "<...>" the distance output signal is displayed in the form of a respective numerical value.
A presence surveillance system according to any of claims 1 to 5, wherein said distance output signal is displayed via a bar graph.
A presence surveillance system according to any of claims 1 to 6, further comprising a direction detector circuit for generating a direction output signal indicative of the direction of the location of the R.F. transmitter with respect to the location of the monitoring device.
A presence surveillance system according to any of claims 2 to 7,
wherein the monitoring device is designed such that it responds to a plurality of different threshold values,
the comparing section of the microprocessor section being designed and controlled to compare the value of the distance output signal to at least one out of said plurality of different threshold values, and
the alarm section of the monitoring device being designed and controlled to generate an alarm each time the value of the distance output signal of the measuring section exceeds one out of the plurality of different threshold values.
A presence surveillance system according to any of claims 2 to 8, wherein the or each of the predetermined threshold distance/-s is presettable to a value to be at most the value of the predetermined distance range, but otherwise freely adjustable, via the keyboard and/or the display of the mobile phone apparatus or via the menu program unit thereof, respectively.
A presence surveillance system according to any of claims 1 to 9, wherein the actual distances are recallable into the display of the mobile phone apparatus by means of the keyboard thereof.
A presence surveillance system according to any of claims 7 to 10, wherein the direction of the R.F. transmitter with respect to the monitoring device is recallable by means of the keyboard of the mobile phone apparatus, such that the direction is indicated by the display and/or via at least one out of the alarms of the mobile phone apparatus or alternatively via a separate audible or visual or sensual alarm such as e.g. a beep, an LED or a buzzer, respectively.
A presence surveillance system according to any of claims 2 to 10, wherein the actual distances are indicated on the display of the mobile phone apparatus, when the or alternatively any out of the predetermined threshold distance/s is exceeded by the actual distance.
A presence surveillance system according to any of claims 7 to 12, wherein the direction of the R.F. transmitter with respect to the monitoring device is indicated on the display and/or via at least one out of the alarms of the mobile phone apparatus or alternatively via a separate audible or visual or sensual alarm such as e.g. a beep, an LED or a buzzer, respectively, upon exceeding of a predetermined threshold distance by the actual distance.
A presence surveillance system according to any of claims 1 to 13, wherein the R.F. transmitter is hermetically sealed into a waterproof casing.
A presence surveillance system according to one of claims 1 to 14, wherein the R.F. transmitter is incorporated into a bracelet attacheable to a wrist, an arm, an upper part of the body, an ankle, a leg, the neck or the like of a person.
A presence surveillance system according to any of claims 1 to 15, wherein further the monitoring device comprises an SMA - double line joint and quarter wave antenna and the R.F. transmitter comprises an integrated double line antenna.
The mobile phone apparatus of a presence surveillance system according to any of claims 1 to 8, 11 and 12, the mobile phone apparatus comprising incorporated therein the monitoring device of the system.
A cordless phone installation comprising a cordless phone-base-station and a cordless mobile phone apparatus which is the mobile phone apparatus of a presence surveillance system according to any of claims 1 to 8, 11 and 12, the cordless phone apparatus comprising incorporated therein the monitoring device of the system.