WO2015158265A1

WO2015158265A1 - System and method for locating assets equipped with a transponder

Info

Publication number: WO2015158265A1
Application number: PCT/CN2015/076671
Authority: WO
Inventors: Jonathan Philip Lewis-Evans; Alexander John Key
Original assignee: Jonathan Philip Lewis-Evans; Alexander John Key
Priority date: 2014-04-15
Filing date: 2015-04-15
Publication date: 2015-10-22
Also published as: HK1198863A2

Abstract

Provided is a method and system for locating mis-placed, lost or stolen assets. In such a system, each asset is equipped with a transponder which issues coded signals when activated by a control communication, the coded signals enabling a tracking unit to direction find said asset. A method of locating an asset includes providing an unmanned aerial vehicle (UAV) with a wireless transceiver and using said UAV, when airborne, as a wireless signal relay station in the system. The UAV is arranged to relay wireless signals via its transceiver between components of the system, for example between an asset when issuing coded beacon signals and the tracking unit.

Description

SYSTEM AND METHOD FOR LOCATING ASSETS EQUIPPED WITH A TRANSPONDER

Technical Field

The invention relates to a system and a method for locating an asset equipped with a transponder where the transponder issues coded signals when activated by a control communication, wherein said coded signals enable a tracking unit to direction find said asset.

Background Art

Known asset location and recovery systems typically provide a specialized locating device such as a transponder to be associated with an asset such as a motor vehicle which a user may wish to attempt to recover should it be moved without the user's permission, e.g. is stolen.

Some known asset locating and recovery systems enable the transponder to use a radio network to communicate with an operations control centre 'OCC'. The OCC is the management centre which manages subscribers and which controls asset location and recovery when a report or alert is received that an asset has been stolen, etc.

Existing asset location and recovery systems typically make use of a recovery vehicle or tracking vehicle which is directed to the anticipated location of a stolen asset either by the OCC or by an on-board device which provides radio frequency 'RF' direction finding information. This often comprises a signal strength indication and a detected signal direction relative to the recovery vehicle of the detected source of the signal, i.e. the stolen asset such as a motor vehicle.

The radio networks used by existing asset location and recovery systems often comprise a network of fixed location communication receivers/ transmitters/ transceivers and antennas. Maintaining a high percentage geographic coverage of a territory using a solely fixed site network may require an operator to deploy a large number of fixed location antenna sites with substantial associated costs. These costs include such things as: the cost of the equipment; the site purchase; lease or rental costs; site license costs; and/or site installation, maintenance and support costs. Furthermore, sites that provide the greatest geographical area coverage at a given transmission power or the best reception range are often valued at a premium. There may be competition for such sites from other wireless or radio network operators. Such sites often include those where an antenna can be placed at a substantially higher altitude than the surrounding geography such as on hills, mountains, tall buildings or dedicated tall antenna masts.

As an alternative to fixed location sites in the radio network, some operators have deployed mobile receivers/transmitters/transceivers and antennas carried by vehicles or piloted aircraft to supplement the coverage provided by fixed sites. Mobile receivers/transmitters/transceivers and antennas have the advantage that they can be deployed to a particular geographic area where transmission/reception is required for a given time period, and then moved and deployed again elsewhere if the need arises in a different area.

The use of piloted aircraft is effective for such mobile coverage because of the speed with which aircraft can reach a required coverage area, and the longer distances of radio transmission and reception range that can be achieved at the altitude at which they normally fly. Additionally because line of sight radio range is often greater, an aircraft flying over an urban area may receive a radio signal without clutter and noise compared to ground level reception. Piloted aircraft are also able to move rapidly across areas with few or poor quality roads and operate in areas difficult for motor vehicles to traverse.

In dangerous recovery situations, for example where assets are being recovered from criminals, piloted aircraft provide a safety advantage to individuals involved in the tracking, locating and recovery of the assets. The pilots of the aircraft can monitor and observe from a height out of notice of criminals or range of any weapons they might possess.

Piloted aircraft are, however, in many respects, almost prohibitively expensive to operate due to their considerable operating costs such as their leasing, purchase, fuelling, and maintenance among other costs. Consequently, piloted aircraft are not often utilized in public subscription stolen asset location and recovery systems.

Technical Problem

An object of the invention is to mitigate or obviate to some degree one or more problems associated with known asset location and recovery systems .

Another object of the invention is to increase the range of reception and transmission of existing fixed radio network sites in an asset location and recovery system .

Another object of the invention is to provide coverage in areas of an asset location and recovery system where no fixed antenna site has been deployed.

Technical Solution

In a first main aspect, the invention provides a method in a system for locating an asset having an asset equipped with a transponder which issues coded signals when activated by a control communication, said coded signals enabling a tracking unit to direction find said asset, said method comprising the steps of: providing an unmanned aerial vehicle (UAV) with a wireless transceiver; and using said UAV, when airborne, as a wireless signal relay station to relay wireless signals via said UAV transceiver from at least a first component to at least a second component of the system for locating an asset.

In a second main aspect, the invention provides a system for locating an asset, comprising: an asset equipped with a transponder which issues coded signals when activated by a control communication; a tracking unit to direction find said asset, wherein said coded signals from the transponder enable the tracking unit to direction find said asset; and an unmanned aerial vehicle (UAV) with a wireless transceiver, wherein said UAV is configured as a wireless signal relay station to relay wireless signals via said UAV transceiver from at least a first component to at least a second component of the system for locating an asset.

Advantageous Effects

the invention concerns a method for an asset location system to determine the location and the subsequent recovery of assets such as motor vehicles, although the invention can equally well be used with other mis-placed, lost or stolen physical assets.

Description of Drawings

The foregoing and further features of the present invention will be apparent from the following description of preferred embodiments which are provided by way of example only in connection with the accompanying figures, of which:

Fig. 1 is a schematic diagram of an embodiment of an asset location system according to the invention;

Fig. 2 is a schematic diagram of an embodiment of a UAV for use in the invention; and

Fig. 3 is a schematic diagram of another embodiment of a UAV for use in the invention.

Mode for Invention

The following description is of preferred embodiments by way of example only and without limitation to the combination of features necessary for carrying the invention into effect.

Reference in this specification to 'one embodiment' or 'an embodiment' means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase 'in one embodiment' in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not other embodiments.

Generally speaking, the invention concerns a method for an asset location system to determine the location and the subsequent recovery of assets such as motor vehicles, although the invention can equally well be used with other mis-placed, lost or stolen physical assets.

A physical asset may comprise any of: a vehicle of any type including an automobile, a boat, an airplane, etc.; a person; an animal; cargo including containerized goods; manufacturing, construction or agricultural plant or machinery; bank money delivery boxes; or any other item which has value to an asset owner sufficient to warrant subscription to an asset location and recovery system for recovery of the asset in the event that it is mis-placed, lost or stolen or moved to another location without the owner's permission. One skilled in the art will understand that the asset location system according to the invention merely requires a suitable locating device such as a transponder to be associated with an asset of any type in order for the system to track and locate said transponder and by inference the asset associated with the transponder. The skilled person will also understand that, with the increasing miniaturization of electronic circuitry and devices, many opportunities arise for secreting a suitably adapted transponder on or in an asset. This may involve integrating the transponder into the asset to tap into the asset's power supply or it may involve providing the asset with an independent power supply, possibly comprising long life batteries or the like. In the case of a person, for example, the transponder may be secreted in the lining of clothing or even secreted or integrated into a personal electronic product such as a laptop computer, personal digital assistant or mobile phone, for example. It may even be implanted under the skin as is already done with pets.

A locating device such as a transponder is installed, worn or somehow associated with such an asset or a group of such assets. Where the assets are containerized, for example, the transponder may be associated with the container or one of the group of containerized assets. Hereinafter, the description will refer to motor vehicles as the physical assets and theft as the cause or circumstance of unauthorized or unintended removal or loss merely by way of illustration only. It will be appreciated that other types of assets, stolen, lost or mis-placed under any circumstances can also be tracked.

Referring to Fig. 1, shown is a schematic diagram of an asset location system 10 according to the invention. The system 10 comprises an operations control centre 'OCC' 12 for managing subscribers and for vehicle locating and recovery processes, a fixed radio network 14 for communicating signals between the components of the system 10, a 'stolen' motor vehicle 16, a recovery vehicle or tracking unit 20 with signal processing equipment 22 and at least one UAV 17 having a wireless transceiver 19.

The OCC 12 may be a server-based system including means for processing computer readable instructions for implementing the methods hereinafter described. In some examples, the OCC 12 may include at least one database (not shown) for maintaining subscribers' data, etc. The processing means and computer readable instructions may be provisioned as suitable hardware and software resources which may be implemented in the form of computing devices having a storage and processing means for encoding stored computing instructions.

The motor vehicle 16 is provisioned with a transponder 28 which issues coded beacon signals once it is activated by a control message received from the OCC 12.

In operation of this arrangement, if the OCC 12 or a subscriber to the asset location system 10 becomes aware that, say, the vehicle 16 may have been lost or stolen, the OCC 12 or said subscriber may request status and location data for the vehicle 16. After a period of time, the OCC 12 will return to the requestor the status and location data for the vehicle 16 if this has been received or is easily determinable. The status and location information may be determined from periodic signals exchanged between the OCC 12 and the vehicle's transponder 28 over the fixed wireless network 14 or some other available communications system. However, if no up to date status and location data is returned or easily determinable, the OCC 12 may examine a last known location of the vehicle 16 and the time it was at that location. Based on the last known location and the elapsed time since the vehicle 16 was at its last known location, the OCC 12 may determine a geographical area within which the stolen asset is expected to be currently located.

In any event, the OCC 12 transmits an activation or control message to the transponder 28 of the vehicle 16 to awaken the transponder 28 and cause it to commence transmitting its location or beacon information in accordance with a pre-programmed sequence of transmissions on a selected communication medium or on any communication medium as determined locally as available by the transponder 28.

Normally, the activation message from the OCC12 is transmitted over the fixed wireless network 14 and received by the transponder 28 by that medium. However, if the vehicle 16 is outside a transmission area of the network 14 or in a wireless signal black-spot, the activation signal may not be received at the transponder 28.

In one embodiment of the invention, once the OCC 12 receives an alert that the vehicle 16 is missing/stolen and the OCC 12 fails to receive any acknowledgement from the transponder 28 or any other component of the system 10 that the transponder 28 has been activated, an OCC operative may instruct a tracking unit vehicle 20 to make its way to a last known location or an anticipated location of the vehicle 16. The tracking unit operator or a team of such operators may be instructed to launch a UAV 17 to provide a wireless signal relay station within the asset location system 10 whereby one of a number of repeated activation commands from the OCC 12 may successfully be relayed to the transponder 28 to activate it and whereby at least an activation acknowledgement message from the transponder 28 may be relayed to the OCC 12.

The foregoing represents just one way in which a UAV 17 may be usefully used in the asset location and recovery system 10 to improve or extend the network wireless coverage of the system 10 and to relay a wireless signal via said UAV transceiver 19 from a first component, in this case the OCC 12, to a second component, in this case the vehicle 16, of the system 10 .

It will be understood that the activation signal from the OCC 12 may not be sent directly from the OCC 12 to the UAV 17 for relaying to the transponder 28, but may be firstly relayed through a part of the fixed radio network 14 or any other communications links or media available to the system 10 prior to being received by the UAV 17 for relaying to the transponder 28. Furthermore, the UAV 17 may be configured to relay signals to and/or from the OCC 12 to other components in the system 10 such as the tracking vehicle 10, a network signal relay station (not shown) in the fixed radio network 14 or another UAV 21.

In a preferred arrangement of the system 10, the UAV 17 is usefully employed in vehicle tracking whereby it is launched by an operative at or near an anticipated or predicted location of the vehicle 16 in order to at least relay coded beacon signals from the transponder 28 to the tracking vehicle 20. In this embodiment as depicted in Fig. 1, once the UAV 17 is launched, the tracking vehicle establishes an uplink/downlink communication connection to the airborne UAV 17. This may prompt the UAV 17 to turn on its signal processing apparatus (not shown), although this may already be powered up. The UAV 17, if launched in a suitable vicinity within wireless range of the transponder 28, will receive coded beacon signals from the transponder and/or other information enabling the tracking vehicle 20 to calculate a location for the vehicle 16. The UAV 17 may be configured to process the coded beacon signals to determine a received signal strength indication 'RSSI' or a received channel power indication 'RCPI' for the received coded beacon signals and/or a direction of propagation of the coded beacon signals and relay this information to the tracking vehicle 20. The UAV 17 may also be configured to provide to the tracking vehicle 20 information comprising any of its own location, altitude, direction and orientation. Armed with the information provided to it by the UAV 17, the tracking vehicle 20 may determine or calculate an expected location or direction of the location of the vehicle 16 by known methods leading to possible recovery of the vehicle 16.

The foregoing represents another way in which a UAV 17 may be usefully used in the asset location and recovery system 10 to relay a wireless signal or information via said UAV transceiver 19 from a first component, in this case the 'stolen' vehicle transponder 28, to a second component, in this case the tracking vehicle 20, of the system 10 .

It will be understood that the signals or information from the transponder 28 may be received by the UAV 17 and relayed to other components in the system 10 such as the OCC 12, a network signal relay station (not shown) in the fixed radio network 14 or another UAV 21.

In the foregoing methods, a plurality of UAVs 17, 21 may be employed, each UAV 17, 21 having a transceiver 19 and each being capable of relaying wireless signals and information between components of the system 10.

In one embodiment, the or each UAV 17, 21 is controlled to fly a flight path and to provide RSSIs and/or directions of propagation of the beacon signals of the vehicale 16 for a plurality of points along said flight path and to transmit said plurality of RSSIs and/or directions of propagation to another component of the asset locating system such as the tracking vehicle 20. The provision of a number of RSSIs and/or directions of propagation together with knowledge of the flight path enables the tracking vehicle 20 to calculate by triangulation and other techniques the location of the missing vehicle 16. Where a plurality of UAVs 17, 21 is deployed, each may be controlled to fly a respective flight path. The flight paths may be predetermined, although, in some circumstances, the UAVs may autonomously determine their own flight paths within a specified geographical region.

In another embodiment, the UAV 17 may be autonomously controlled to occupy a flight position determined in part by a current position of the tracking unit 20 and/or a current predicted or calculated position of the vehicle 16 in order that the UAV maintains a wireless coverage over at least one or both of the tracking unit 20 and vehicle 16.

The or each UAV 17, 21 may be remotely controlled by an operative using a line of sight control system or remotely controlled by an operative located out of sight of the UAV using signals transmitted over a communications link to the UAV. These control options are more useful where a single UAV 17 or a very small number of UAVs 17, 21 are being deployed. Where a plurality of UAVs is being deployed, it is preferred that these are controlled autonomously when airborne and where they may be autonomously controlled to fly in a spaced apart pattern.

In one embodiment where a plurality of UAVs 17, 21 is deployed, the method may include the steps of: receiving at each UAV 17, 21 a signal from the asset transponder 28; processing said signal to determine a received signal strength indication (RSSI) and/or direction of propagation of the beacon signals; and transmitting at least said RSSI and/or direction of propagation of the beacon signals to the tracking vehicle 20. Armed with the different RSSIs and/or different directions of propagation of the beacon signals from the plurality of UAVs 17, 21 and having knowledge of the positions of the UAVs 17, 21 when the RSSIs/beacon signal directions were determined enables the tracking vehicle to triangulate a position for the transponder 28 and thus the missing vehicle 16.

In one embodiment, the UAV 17 may be configured to have a weight below a threshold at which it is required for a UAV flight operator to obtain a flying certificate from a civil aviation authority.

The method may include operating the UAV 17 to remain below a predetermined height where said predetermined height may comprise a height ceiling for UAVs under civil aviation rules. That being said, there are advantages to controlling the UAV 17 to a highest permissible or operational height in that this increases the wireless area coverage provided by the UAV 17 as a wireless relay station. In some embodiments, the method may include operating the UAV 17 at a height which exceeds the height of a nearest located transmission antenna of the fixed radio network 14 of the system 10.

Although not shown in Fig. 1, the transceiver 19 of the or each UAV 17, 21 may be enabled for communicating via a cellular wireless network. As such, the UAV 17, 21 may be configured to receive a SIM card for cellular mobile communications. Consequently, where the UAV 17, 21 is unable to make wireless contact directly with any component of the system 10 or via the fixed radio network 14, it can attempt to establish a communications link though a mobile cellular network where cellular coverage permits it.

The use of one or more UAVs in an asset location and recovery system 10 as hereinbefore described provides a number of technical benefits such as increasing the range of reception and transmission of the system's existing fixed radio network, affording access to areas where vehicular access is difficult, flying quietly overhead in an unobtrusive manner, and allowing a skilled pilot to remain on base in a remote control centre while the UAV is carried to its place of deployment by a less skilled operator, thus potentially saving on pilot travel time to the location.

Also, to provide direction finding triangulation information on a lost or stolen asset, a UAV may be controlled to fly a path known to the controller and to receive different compass bearings of the signal from the lost or stolen asset transponder. Triangulation of these bearings may be used to give a more exact location of the lost or stolen asset.

Also, a UAV may be configured to provide a live aerial video feed of the area around a stolen or lost asset useful to a commander of a tracking and recovery operation. This may be used to determine resources required to recover the asset and the safety of ground operatives involved in the recovery operation. A UAV may be used to track and locate in areas with limited ground access for motor vehicles or on foot.

Fig. 2 shows an embodiment of a UAV 17, 21 having a transceiver 19 as hereinbefore described and memory and processing circuitry 30 for controlling operation of the transceiver 19. The memory and processing circuitry 30 comprises memory means for storing signals and/or other data for processing and machine readable instructions which, when executed by a processor of the circuitry 30, processes said received signals and/or data in accordance predefined process steps. The UAV 17, 21 includes an antenna module 32 which, in this embodiment, is supported underneath the UAV 17, 21, although the module may be mounted elsewhere on the UAV 17, 21.

In the present invention, the UAV(s) 17, 21 is(are) used to direction find a lost, stolen or misplaced asset such as a stolen vehicle 16 based on the asset's beacon signals. Direction finding (DF), or radio direction finding (RDF), refers to the measurement of the direction from which a received signal was transmitted. This can refer to radio or other forms of wireless communication. By combining the direction information from two or more suitably spaced receivers/antennas (or a single mobile receiver/antenna), the source of a transmission may be located in space via triangulation. The doppler or pseudo-doppler direction finding (DF) technique is a phase based DF method that produces a bearing estimate on the received signal by measuring the doppler shift induced on the signal at the receiver/antenna or receivers/antennas.

Referring again to Fig. 2, it can be seen that the antenna module 32 has a plurality of antennas (or receivers) 34, preferably four. These are preferably spatially arranged in an array. The arrowed line A in Fig. 2 signifies that, in order to induce a doppler shift at the antennas 34, any one of the following techniques may be applied: (1) the UAV 17, 21 is itself controlled to rotate about its vertical axis; (2) the antenna module 32 is controlled to rotate relative to the UAV 17, 21; and (3) more preferably, each antenna 34 of the array is signal sampled in turn. In this latter case, the antennas 34 are preferably arranged in a circular array on the module 32, but do not need to be physically rotated.

Fig. 3 shows a further embodiment of a UAV 17, 21 having a transceiver 19, circuitry 30 and an antenna module 32. In this embodiment, the module 32 has a single antenna/receiver 36. The arrowed line B signifies that either the UAV 17, 21 is controlled to rotate about its vertical axis or that the antenna module 32 is controlled to rotate relative to the UAV 17, 21. In both cases, the antenna/receiver 36 is mounted on the module 32 such that it is offset a distance x from the vertical axis, i.e. from the vertical centre of rotation of the UAV 17, 21. Consequently, in either case, the single antenna 36 is physically moved in a circle to thereby induce a doppler shift to enable direction finding on a received beacon signal.

In general, the invention concerns a method and system for locating mis-placed, lost or stolen assets. In such a system, each asset is equipped with a transponder which issues coded signals when activated by a control communication, the coded signals enabling a tracking unit to direction find said asset. A method of locating an asset includes providing an unmanned aerial vehicle (UAV) with a wireless transceiver and using said UAV, when airborne, as a wireless signal relay station in the system. The UAV is arranged to relay wireless signals via its transceiver between components of the system, for example between an asset when issuing coded beacon signals and the tracking unit

The apparatus described above may be implemented at least in part in software. Those skilled in the art will appreciate that the apparatus described above may be implemented at least in part using general purpose computer equipment or using bespoke equipment mounted on an aerial vehicle.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only exemplary embodiments have been shown and described and do not limit the scope of the invention in any manner. It can be appreciated that any of the features described herein may be used with any embodiment. The illustrative embodiments are not exclusive of each other or of other embodiments not recited herein. Accordingly, the invention also provides embodiments that comprise combinations of one or more of the illustrative embodiments described above. Modifications and variations of the invention as herein set forth can be made without departing from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are indicated by the appended claims.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word 'comprise' or variations such as 'comprises' or 'comprising' is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art.

Claims

A method in a system for locating an asset having an asset equipped with a transponder which issues coded signals when activated by a control communication, said coded signals enabling a tracking unit to direction find said asset, said method comprising the steps of:

providing an unmanned aerial vehicle (UAV) with a wireless transceiver; and

using said UAV, when airborne, as a wireless signal relay station to relay wireless signals via said UAV transceiver from at least a first component to at least a second component of the system for locating an asset.
The method of claim 1, wherein the first component of the asset locating system comprises the asset equipped with a transponder and the second component of the asset locating system comprises any one or more of the tracking unit, a network signal relay station, another UAV, and an operation control centre (OCC) of the asset locating system.
The method of claim 1, wherein the first component of the asset tracking system comprises an operation control centre (OCC) of the asset locating system and the second component of the asset locating system comprises any one or more of the tracking unit, a network signal relay station, another UAV, and the asset equipped with a transponder.
The method of any one of claims 1 to 3, wherein the UAV is remotely controlled by an operative using a line of sight control system when airborne.
The method of any one of claims 1 to 3, wherein the UAV is remotely controlled by an operative located out of sight of the UAV using signals transmitted over a communications link to the UAV when airborne.
The method of any one of claims 1 to 3, wherein the UAV is controlled autonomously when airborne.
The method of any one of claims 4 to 6, wherein the UAV is controlled to remain below a first predetermined height when airborne.
The method of any one of claims 4 to 7, wherein the UAV is controlled to remain above a second predetermined height when airborne.
The method of any one of the preceding claims, wherein a plurality of UAVs is utilized in the asset locating system.
The method of any one of the preceding claims, further comprising the steps of:

receiving at the or each UAV a signal from the asset transponder;

processing said signal to determine a received signal strength indication (RSSI) and/or a direction of propagation of the coded signals; and

transmitting said RSSI and/or a direction of propagation of the coded signals to another component of the asset locating system.
The method of claim 10 when dependent on claim 9, wherein each of the plurality of UAVs transmits a respective RSSI and/or a direction of propagation of the coded signals to another component of the asset locating system.
The method of claim 10 or claim 11, wherein the or each UAV also transmits to another component in the system any one or more of its own direction, altitude, location and orientation.
The method of any one of claims 10 to 12, wherein the or each UAV is controlled to fly a flight path and to provide RSSIs and/or directions of propagation of the coded signals for a plurality of points along said flight path and to transmit said plurality of RSSIs and/or directions of propagation of the coded signals to another component of the asset locating system.
The method of claim 13, wherein the or each UAV is controlled to fly a predetermined flight path.
The method of any one of the preceding claims, wherein the UAV is controlled to occupy a flight position determined in part by a current position of the tracking unit and/or a current predicted or calculated position of the asset.
The method of any one of the preceding claims, wherein the transceiver of the UAV is enabled for communicating via a cellular wireless network.
A system for locating an asset, comprising:

an asset equipped with a transponder which issues coded signals when activated by a control communication;

a tracking unit to direction find said asset, wherein said coded signals from the transponder enable the tracking unit to direction find said asset; and

an unmanned aerial vehicle (UAV) with a wireless transceiver, wherein said UAV is configured as a wireless signal relay station to relay wireless signals via said UAV transceiver from at least a first component to at least a second component of the system for locating an asset.
The system of claim 17, wherein the first component of the asset locating system comprises the asset equipped with a transponder and the second component of the asset locating system comprises any one or more of the tracking unit, a network signal relay station, another UAV, and an operation control centre (OCC) of the asset locating system.
The system of claim 17, wherein the first component of the asset tracking system comprises an operation control centre (OCC) of the asset locating system and the second component of the asset locating system comprises any one or more of the tracking unit, a network signal relay station, another UAV, and the asset equipped with a transponder.
The system of any one of claims 17 to 19, wherein the UAV is arranged to be remotely controlled by an operative using a line of sight control system when airborne.
The method of any one of claims 17 to 19, wherein the UAV is arranged to be remotely controlled by an operative located out of sight of the UAV using signals transmitted over a communications link to the UAV when airborne.
The system of any one of claims 17 to 19, wherein the UAV is arranged to be controlled autonomously when airborne.
The system of any one of claims 20 to 22, wherein the UAV is arranged to be controlled to remain below a first predetermined height when airborne.
The system of any one of claims 20 to 23, wherein the UAV is arranged to be controlled to remain above a second predetermined height when airborne.
The system of any one of claims 17 to 24, wherein the asset locating system includes a plurality of UAVs.
The system of any one of claims 17 to 25, wherein the or each UAV is arranged to:

receive a signal from the asset transponder;

process said signal to determine a received signal strength indication (RSSI) and/or a direction of propagation of the coded signals; and

transmit said RSSI and/or a direction of propagation of the coded signals to another component of the asset locating system.
The system of claim 26 when dependent on claim 25, wherein each of the plurality of UAVs is arranged to transmit a respective RSSI and/or a direction of propagation of the coded signals to another component of the asset locating system.
The system of claim 26 or claim 27, wherein the or each UAV is arranged to transmit to another component in the system any one or more of its own direction, altitude, location and orientation.
The system of any one of claims 26 to 28, wherein the or each UAV is controlled to fly a flight path and to provide RSSIs and/or directions of propagation of the coded signals for a plurality of points along said flight path and to transmit said plurality of RSSIs and/or directions of propagation of the coded signals to another component of the asset locating system.
The system of claim 29, wherein the or each UAV is controlled to fly a predetermined flight path.
The system of any one of claims 17 to 30, wherein the UAV is controlled to occupy a flight position determined in part by a current position of the tracking unit and/or a current predicted or calculated position of the asset.
The system of any one of claims 17 to 31, wherein the transceiver of the UAV is enabled for communicating via a cellular wireless network.