WO2005059585A1

WO2005059585A1 - Signal intensity mapping

Info

Publication number: WO2005059585A1
Application number: PCT/GB2004/005272
Authority: WO
Inventors: Barry Stephen
Original assignee: Audiotel International Ltd
Current assignee: Audiotel International Ltd
Priority date: 2003-12-19
Filing date: 2004-12-16
Publication date: 2005-06-30
Anticipated expiration: 2006-06-19
Also published as: GB2409593A; GB0329544D0

Abstract

A counter surveillance detector apparatus for locating electronic eavesdropping devices or other target devices or objects. The detector apparatus includes: at least one radiating and/or non-radiating transducer for receiving electromagnetic energy to enable detection of a target object; a location positioning device adapted to determine the spatial location of the detector apparatus relative to a sweep environment; and a control unit adapted to receive location information from the location positioning device and to receive signal intensity information from the transducer, and to store corresponding location information and intensity information in association with one another. The location sensing may be performed by ultrasonic or electromagnetic techniques. A signal intensity map is generated showing measured signal intensity as a function of location in the sweep environment.

Description

SIGNAL INTENSITY MAPPING

The present invention relates to counter surveillance equipment suitable for locating electronic eavesdropping devices and electronic equipment. More generally, the invention relates to detectors suitable for detecting the presence of any target devices or objects that can be detected by interaction with, or response to, an electromagnetic field emitted by the detector, or any target devices or objects that can be detected by sensing electromagnetic radiation emitted therefrom.

Where the threat of electronic espionage exists, it is common practice to clear and secure sensitive locations (e.g. buildings and rooms within buildings) by performing a Technical Surveillance Counter Measures (TSCM) sweep.

Part of any TSCM sweep includes using electronic counter surveillance equipment to detect and locate covert eavesdropping devices.

In the prior art, a TSCM operator has had to move a detector around the area being 'swept', while constantly monitoring the instantaneous output from the electronic eavesdropping device detector in an attempt to identify any anomalies in the readings.

Generally, the detectors fall into two classes. A, first class is particularly adapted to locate target devices that are active, in the sense that they are actively transmitting electromagnetic energy at the time that the sweep is being carried out. Typically, this technique requires a 'non-radiating detector' (or 'scanner') which listens for transmissions across a wide band of the electromagnetic spectrum or at selected frequencies therein. ^"We shall refer to this class of detectors as non-radiating detectors. An example of this type of detector is a broadband field strength meter. A second class of detectors is particularly adapted to locate target devices that are passive, in the sense that they might not be actively emitting electromagnetic radiation at the time that the sweep is being carried out. Typically, this technique requires a 'radiating detector' which actively emits radiation so as to cause a resultant emission (e.g. modification of electromagnetic field by reflection or re-radiation at another frequency) from the target device. Examples of this type of detector are metal detectors and non-linear junction detectors (NLJD's) which detect metal-metal junctions and semiconductor junctions by irradiating them and listening for a harmonic response.

By way of example, when using a non-radiating detector, such as a broadband field strength meter, the indication from the equipment will increase as an active target device is approached and decrease as the detector moves away from the active target device.

In a typical counter surveillance sweep environment (e.g. an office), there may be many innocent sources of electromagnetic radiation (e.g. personal computer monitors) which means that identifying the location of a covert eavesdropping device becomes a non-trivial task.

If the TSCM operator could visualise the sweep environment in terms signal intensity from one or more electronic eavesdropping device detectors, then the difficulty of identifying the location of the anomalies, and hence any potential covert electronic eavesdropping device, would be greatly reduced.

It is an object of the present invention to provide an apparatus which can produce signal intensity maps of areas and structures during a counter surveillance sweep. According to one aspect, the present invention provides a detector apparatus for detecting the existence of target objects by their emission of radiation or by their interaction with, or response to, an electromagnetic field emitted by the detector, within a sweep environment, comprising: at least one radiating and/or non-radiating transducer for receiving electromagnetic energy to enable detection of a target object; a location positioning device adapted to determine the spatial location of the detector apparatus relative to a sweep environment; and a control unit adapted to receive location information from the location positioning device and to receive signal intensity information from the transducer, and to store corresponding location information and intensity information in association with one another.

According to another aspect, the present invention provides a method for detecting the existence of target objects by their emission of radiation or by their interaction with, or response to, an electromagnetic field emitted by a detector apparatus, within a sweep environment, comprising the steps of: determining the spatial location of the detector apparatus relative to a sweep environment by way of a location positioning device; receiving electromagnetic energy from at least one radiating and/or non- radiating transducer to enable detection of a target object; and processing, in a control unit, the received spatial location information from the location positioning device and the signal intensity information from the transducer, and storing the corresponding location information and intensity information in association with one another in a memory in the detector.

Embodiments of the present invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a block diagram of a signal intensity mapping unit; and Figure 2 is a flow diagram illustrating a process flow for the control unit of figure 1.

Referring to figure 1, a signal intensity mapping apparatus 10 includes a location positioning device 1, one or more radiating detectors 2 for detecting passive target devices or objects, one or more non-radiating detectors 3 for detecting active target devices or objects, a control unit 4, a data storage unit 5 and a display unit 6. The radiating and/or non-radiating detectors 2, 3 include respective transducers 11, 12 for transmitting and/or receiving electromagnetic radiation. The transducers 11, 12 may be integrated into a common housing 16 together with the rest of the components of the signal intensity mapping apparatus 10. However, in a preferred arrangement as illustrated in figure 1, the transducers 11, 12 are mounted in a search head 15 which is remote from, but electrically connected to, a base unit 16 housing the remaining components.

The radiating detectors 2 preferably include a non-linear junction detector (NLJD) and a metal detector as known to a person skilled in the art.

The non-radiating detectors 3 preferably include a harmonic receiver and a broadband detector as known to the person skilled in the art.

In a preferred embodiment, the location positioning device 1 comprises an electronic position sensor la which is adapted to determine its location within the TSCM sweep environment. This position sensor la may operate in a number of possible ways.

In a first arrangement, the position sensor la comprises at least one ultrasonic transducer adapted to determine distance of the sensor from a predetermined reference object or to determine distances from a set of predetermined reference objects. For example, in an office environment, one or more ultrasonic transducers may be adapted to determine distance from one or more end walls, ceiling or floor of the office.

The location positioning device 1 may further include an orientation sensor lb, such as an electronic compass or similar device which may work in conjunction with directional position sensors such as the ultrasonic transducers described above, to assist the location positioning device 1 in determining an absolute location.

In a further arrangement, the location positioning device uses optical or other electromagnetic energy to determine its position within the TSCM sweep environment. This may be performed by reference to one or more beacons previously positioned within the TSCM sweep environment at one or more predeterrnined locations. The beacon or beacons may be active, in transmitting energy detectable by the location positioning device 1, or may be passive in merely reflecting or re-radiating energy transmitted by the location positioning device. Various such • position sensing systems using optical or other electromagnetic signals are found in the art, using triangulation or other techniques. In large sweep areas, position sensing may be assisted by, for example, a GPS system.

The location positioning device 1 may further include a direction sensor lc which determines the direction in which the transducer search head 15 is facing. This may be useful where the detector 2 or 3 in operation is highly directional as it enables the position of detectable signals to be more accurately determined. It will be understood that some or all of the functions of position sensing, orientation sensing and direction sensing may be carried out in an integrated unit and some of the sensed parameters can be determined by reference to the other sensed parameters.

More generally, the position sensor la, the orientation sensor lb and the direction sensor lc may be adapted to determine the location of the remote search head 15, if that location is significantly different from, or if not deducible from, the position of the base unit housing 16. This may be particularly important where the sweep head 15 is coupled to the base unit 16 by way of a flying lead. In such circumstances, some or all of the components of the location positioning device 1 may be situated within the remote search head 15 rather than in the base unit housing 16.

In the preferred embodiment, the location positioning device 1 is fully automated and delivers a continuous or intermittent stream of position information to the control unit 4 during operation of the apparatus 10 in a TSCM sweep. However, some of the position sensing activity may be performed by manual intervention by the operator. For example, the user may be prompted to enter position co-ordinates or other location specific information at routine or special intervals.

The position and orientation of the detector apparatus may be obtained relative to a starting position and orientation by way of a suitable motion sensor as also known to a person skilled in the relevant art. The starting position relative to the sweep environment could be determined manually and entered into the control unit 4 by user input, or could be determined electronically using techniques described above. The control unit 4 is preferably a microprocessor module which is adapted to read and store, in memory 5, all the necessary information during a TSCM sweep to enable construction of a signal intensity map of the TSCM sweep environment.

With reference to figure 2, the steps performed in an exemplary control unit 4 comprise, sequentially, reading a position output by the location positioning device 1 (step 21), taking a signal intensify reading from each of the one or more radiating detectors 2 (step 22), taking a signal intensity reading from each of the one or more non-radiating detectors 3 (step 23), storing the information read into the data storage unit 5 (step 24), and updating the display unit 6 with any relevant information useful to the user (step 25). The control unit function then cycles round to restart with a new position output, as shown.

The control unit 4 uses all of the measurements taken to generate a signal intensity map showing, in two- or three-dimensional representations, the signal intensify as a function of position within the TSCM sweep environment.

For instance, the signal map may be a two-dimensional plan view of the sweep environment with varying signal intensify plotted thereon by colour, grey scale, brightness or contour lines or a combination thereof. Alternatively, the signal map may be a simulated three-dimensional perspective view of the sweep environment with the varying signal intensify plotted thereon by colour, grey scale, brightness or contour lines or a combination thereof.

In the preferred embodiment, the display unit 6 displays the signal intensity map of the sweep environment updated in real time as readings are taken so that the operator can obtain rapid visual feedback of swept and unswept areas, anomalies in the readings, and areas worthy of further scrutiny (e.g. with different detection parameters). It will be understood that the expression 'real time' is intended to encompass 'quasi real time' in which there may be short (e.g. up to a few seconds) processing delays before information is presented, or short periods between display refresh intervals.

Although the presence of a display unit 6 in the signal mapping apparatus is preferred, it will be understood that a display or other output unit could be • provided separate from the main apparatus 10. For example, the control unit 4 may simply store all of the relevant information in data storage unit 5 for subsequent download to another device and display thereon, e.g. a personal computer, PDA or the like.

For example, an external interface 7 may be provided coupled to either the data storage unit 5 or the control unit 4 for information download. Similarly, the interface may be used for upload, e.g. to upgrade or modify software in the control unit or to update configuration settings in the detector apparatus 10. The external interface may comprise a hardwire connection or a wireless connection, e.g. RF or infrared.

Referring again to figure 1, in a preferred embodiment the data storage unit 5 is the microprocessor memory. The data storage unit 5 is used to internally store location positions alongside corresponding signal intensify readings. The data storage unit 5 may also be used to store entire signal intensify maps of TSCM environments for subsequent retrieval and use as 'fingerprints' or 'signatures' of structures and areas mapped. For example, a signal intensify map from a previous sweep of a specific area may be recalled and compared to a new sweep.

In the preferred embodiment the display unit 6 is a colour liquid crystal display device, but any suitable display device may be used. The display unit 6 preferably allows the operator to view one or more previously stored maps in conjunction with a current map (e.g. either simultaneously or sequentially) to identify differences between the current map and one which was previously obtained. In another arrangement, the apparatus may display a 'difference' map showing changes in signal intensity, as a function of location, between a current and-previous map. This may be by map overlay or superposition to subtract one set of intensities from another using any suitable mathematical algorithm.

The detector apparatus may also allow for selection of one or more specific non-radiating and / or radiating detector signal intensify outputs for display in each signal intensity map. The signal intensities from each respective detector type may be viewed separately or combined using any appropriate combinatorial algorithm to provide optimum information to the user for analysing the intensify signals and determining the location of any target objects.

The apparatus as described above could be retrofitted to existing electronic eavesdropping device detectors or integrated into new detectors.

Throughout the present specification, the detector outputs for plotting in a map have been described as signal intensities. This term is intended to encompass all forms of detector output that are useful in providing a measure of the proximity of a radiation source and / or a signal strength therefrom. For example, the measured quantity may be an electromagnetic field strength, an amplitude or an intensity value.

The apparatus as described thereby allows a TSCM operator to visualise areas and structures within the counter surveillance sweep environment in one or more detector domains. The apparatus assists the TSCM operator to easily identify signal intensify anomalies, and hence potential covert electronic eavesdropping devices, within the TSCM area or structures being interrogated during the counter surveillance sweep.

The preferred embodiment allows the TSCM operator to obtain signatures or 'fingerprints' of areas and structures within the counter surveillance sweep environment which can subsequently be used as a bench mark, or reference, to further increase efficiency of future counter surveillance sweeps.

Other embodiments are intentionally within the scope of the accompanying claims.

Claims

1. Detector apparatus for detecting the existence of target objects by their emission of radiation or by their interaction with, or response to, an .electromagnetic field emitted by the detector, within a sweep environment, comprising: at least one radiating and/or non-radiating transducer for receiving electromagnetic energy to enable detection of a target object; a location positioning device adapted to determine the spatial location of the detector apparatus relative to a sweep environment; and a control unit adapted to receive location information from the location positioning device and to receive signal intensify information from the transducer, and to store corresponding location information and intensity information in association with one another.

2. The detector apparatus of claim 1 in which the location positioning device comprises a position sensor for determining relative position to a reference point or plane within the sweep environment.

3. The detector apparatus of claim 2 in which the location sensor comprises an ultrasonic transducer.

4. The detector' apparatus of claim 2 in which the location positioning device comprises an electromagnetic transducer.

5. The detector apparatus of claim 1 in which the location positioning device is adapted to determine position relative to one or more active beacons.

6. The detector apparatus of claim 2 in which the location positioning device is adapted to determine position relative to one or more passive objects.

7. The detector apparatus of claim 1 in which the location positioning device further includes an orientation sensor for determining an orientation of the sensor relative to the sweep environment.

8. The detector apparatus of claim 1 in which the location positioning device further includes a direction sensor for determining the direction in which the transducer is facing.

9. The detector apparatus of any preceding claim in which the transducer is mounted in a sweep head that is variable in position relative to a base unit housing other components of the detector apparatus.

10. The detector apparatus of claim 9 in which the location positioning device is adapted to determine the location, orientation and / or direction of the sweep head.

11. The detector apparatus of claim 1 in which the location positioning device comprises a user interface for inputting position co-ordinates or other location specific information.

12. The detector apparatus of claim 1 in which the control unit further includes means for processing said location information and signal intensify information to generate a signal intensity map indicating signal intensify as a function of location in the sweep environment.

13. The detector apparatus of claim 12 further including a display unit, in which the control means is further adapted for displaying a two- or three- dimensional representation of the measured signal intensities as a function of position within the sweep environment.

14. The detector apparatus of claim 13 adapted to update the displayed representation in real time.

15. The detector apparatus of claim 1 or claim 12 further including an external interface for downloading said location information and said signal intensify information and/or said signal intensity maps to an external device.

16. The detector apparatus of claim 12 further including means for displaying at least one previously stored signal intensify map in conjunction with a current signal intensity map.

17. The detector apparatus of claim 16 in which the previous and current intensity maps are overlaid or otherwise superposed.

18. The detector apparatus of claim 12 further including a user input and selection means for selection of signal intensities from one or more specific non-radiating and / or radiating detectors for display on the signal intensify map.

19. A method for detecting the existence of target objects by their emission of radiation or by their interaction with, or response to, an electromagnetic field emitted by a detector apparatus, within a sweep environment, comprising the steps of: determining the spatial location of the detector apparatus relative to a sweep environment by way of a location positioning device; receiving electromagnetic energy from at least one radiating and or non- radiating transducer to enable detection of a target object; and processing, in a control unit, the received spatial location information from the location positioning device and the signal intensity information from the transducer, and storing the corresponding location information and intensity information in association with one another in a memory in the detector.

20. The method of claim 19 further including the step of processing said location information and signal intensity information to generate a signal intensity map indicating signal intensity as a function of location in the sweep environment, and displaying said signal intensity map on a display device.

21. Detector apparatus substantially as described herein with reference to the accompanying drawings.