Tracking and communications device
A portable tracking and communications device ( 10 ) comprises a Global Positioning System (GPS) module and a mobile telephony module, the device including at least a first passive, electronic ground plane simulator comprising a pair of essentially grounded antennae ( 16, 17 ) that are selectively connectable one to the other via a parallel-connected resistor-capacitance resonator ( 18, 19 ), the resonator being tuned to a first predetermined frequency or frequency range.
1. A device comprising:
a housing;
a Global Positioning System (GPS) module including a casing;
a mobile telephony module including a casing;
memory configured to store a mapping perimeter;
a processor configured to determine whether the device lies inside or outside the mapping perimeter;
a first circuit comprising a plurality of antennae each grounded to the housing, wherein the plurality of antennae are selectively connectable in parallel to each other with circuitry including a resistor-capacitor resonator; and
wherein:
the resistor-capacitor resonator is tuned to at least one of a first predetermined frequency or a first predetermined frequency range;
the circuit is configured to provide mobile telephony signals in the device when the plurality of antennae are not connected to one another;
the circuit is configured to provide GPS signals when the plurality of antennae are connected to one another the casing of the GPS module; and
the casing of the mobile telephony module comprise the plurality of antennae.
2. The device according to claim 1 including a microprocessor programmed to selectively connect the plurality of antennae to one another.
3. The device according to claim 2 wherein the microprocessor is programmed to detect activity levels of at least the mobile telephony module in receiving mobile telephony signals and connect the plurality of antennae in dependence on the detected activity levels.
4. The device according to claim 1 including a second circuit including a resonator tuned to a second frequency or a second frequency range different from the first predetermined frequency or the first predetermined frequency range.
5. The device according to claim 4 wherein the respective components of the GPS module and the mobile telephony module are common to the first and second circuits.
6. The device according to claim 1 wherein the mobile telephony module comprises a General Packet Radio System (GPRS) module.
7. The device according to claim 1 wherein two of the plurality of antennae lie in overlapping relation to one another on opposite sides of the device.
8. The device according to claim 7 wherein two of the plurality of antennae are separated from one another by a distance in the range 15 mm to 30 mm.
9. The device according to claim 1 including a wristband secured to the housing, wherein the wristband is configured to releasably secure the device to a wrist of a user.
10. The device according to claim 9 wherein the wristband includes mutually engageable parts lockably securable one to another in order to secure the device to the wrist of the user.
11. The device according to claim 10 wherein the mutually engageable parts include a lock selectively securable and releasable by way of a key distinct from the device.
12. The device according to claim 11 including a data generation and transmission circuit and at least one transmission antenna configured to cause transmission of data.
13. The device according to claim 12 wherein the data generation and transmission circuit is capable of generating and transmitting data in at least one of GPRS format or short message service (SMS) format.
14. The device according to claim 12 wherein the data generation and transmission circuit is operatively connected to a wristband so as to generate and transmit a data signal on rupturing of the wristband.
15. The device to claim 12 wherein the data generation and transmission circuit is operatively connected at least one of the mutually engageable parts so as to generate and transmit a data signal on separating of the mutually engageable parts one from another without releasing of the lock.
16. The device according to claim 1 including a liquid crystal display (LCD) that is capable of displaying device status information.
17. A system including:
a device comprising:
a housing;
a Global Positioning System (GPS) module including a casing;
a mobile telephony module including a casing;
a circuit comprising a plurality of antennae each grounded to the housing, wherein the plurality of antennae are selectively connectable in parallel to each other with circuitry including a resistor-capacitor resonator;
a memory; and
a microprocessor;
wherein:
the resistor-capacitor resonator is tuned to at least one of a first predetermined frequency or a first predetermined frequency range;
the circuit is configured to provide mobile telephony signals in the device when the plurality of antennae are not connected to one another;
the circuit is configured to provide GPS signals when the plurality of antennae are connected to one another; and
the casing of the GPS module and the casing of the mobile telephony module comprise the plurality of antennae; and
a server remote from the device, wherein:
the server has defined therein a polygonal or circular mapping perimeter transmissible to the device;
the memory of the device is capable of storing the mapping perimeter; and
the microprocessor of the device is capable of determining whether the device lies within or outside the mapping perimeter.
18. The system according to claim 17 wherein the perimeter is superimposed on at least one mapping data set.
19. The system according to claim 17 wherein when the mapping perimeter is polygonal; and
wherein the microprocessor includes programmed therein an algorithm that defines a line joining two points so as to intersect a boundary of a polygonal mapping perimeter, and
wherein the position of the device as determined by the GPS module lying on the said line and the microprocessor is capable of determining whether the device lies within or outside the polygon by determining how many times the device would cross the perimeter of the polygonal mapping perimeter if it were to move from its instantaneously prevailing position along the said line to an end of the line lying furthest from it.
20. The system according to claim 17 wherein the mapping perimeter is circular and is defined by longitude and latitude coordinates corresponding to a center point together with a numerical value corresponding to a radius, and wherein the microprocessor is capable of calculating a distance of the device from the center point and, if it exceeds the radius, determining that the device lies outside the perimeter.
21. The system according to claim 17 wherein the microprocessor generates an alert message and causes its transmission via the transmission antenna on the microprocessor determining that the device is outside the perimeter.
22. The system according to claim 17 wherein the server is capable of transmitting data defining the perimeter to the device as an encrypted datagram, and wherein the microprocessor is capable of receiving and decrypting the datagram.
23. The system according to claim 22 wherein the microprocessor is capable of generating a further datagram indicating decryption of the data defining the perimeter and causing transmission of the datagram via the transmission antenna to the server.
24. The system according to claim 17 including a portable device capable of transmitting SMS data messages, further defining the mapping perimeter, from the further device to the portable device in order to define the perimeter therein.
25. The system according to claim 24 wherein the server is capable of transmitting a further SMS message to the further device following decryption of the data defining the perimeter by the microprocessor.
26. The device according to claim 1 including a microprocessor that is programmed to establish the position of the device according to a technique of cell triangulation identification using the mobile telephony module.