GB2329777A - Location system - Google Patents
Location system Download PDFInfo
- Publication number
- GB2329777A GB2329777A GB9800600A GB9800600A GB2329777A GB 2329777 A GB2329777 A GB 2329777A GB 9800600 A GB9800600 A GB 9800600A GB 9800600 A GB9800600 A GB 9800600A GB 2329777 A GB2329777 A GB 2329777A
- Authority
- GB
- United Kingdom
- Prior art keywords
- detector elements
- data
- detector
- detection system
- location
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S1/00—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith
- G01S1/02—Beacons or beacon systems transmitting signals having a characteristic or characteristics capable of being detected by non-directional receivers and defining directions, positions, or position lines fixed relatively to the beacon transmitters; Receivers co-operating therewith using radio waves
- G01S1/04—Details
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Radar Systems Or Details Thereof (AREA)
- Position Fixing By Use Of Radio Waves (AREA)
Abstract
A sensor array comprises a number of detector elements which each detect radiation from a target. In order to determine the location of the individual sensor elements, each emits an individually coded chirped, spread spectrum signal in turn at a known time. Each detector receives the signals from the other detectors, and can determine the relative positions of the detectors from the difference between the times of transmission and reception; this gives relative rangers which can be stored, and the position can be determined by triangulation. Direction of arrival may also be determined.
Description
DETECTION SYSTEM
The present invention relates to detection systems which include a plurality of remotely disposed elements having sensors which serve in combination to detect objects from signals emitted by those objects.
Detection systems are known to be comprised of a plurality of autonomous detector elements. The detector elements are provided with sensors which detect sound, light or electromagnetic radiation, through which the presence of an object emitting signals formed from any of these types of radiation may be detected. Furthermore, the detection system may further determine the location of the object provided that the relative position of each of the detector elements is known. However it is often the case that such detector elements are disposed in an ad hoc manner to the effect that a location of each of the elements forming part of the detection system is unknown.
A technical problem of determining a location of a plurality of detector elements forming part of a detection system is addressed by the present invention.
According to the present invention there is provided a detection system comprising a plurality of detector elements which detector elements each include a communicator for communicating data to and from any other detector element, a data processor coupled to the communicator and arranged in use to send and receive data via the communicator, and a clock coupled to said data processor for providing a temporal reference thereto, wherein said data processor in combination with said communicator of at least one of said detector elements operates to transmit a predetermined signal at a predetermined time to the other detector elements and consequent upon a temporal difference between said predetermined time and a time of reception of said predetermined signals said data processor operates to generate relative distance data representative of a relative distance of said at least one of said detector elements with respect to said other detector elements.
By providing a communicator and a data processor within each of the detector elements, known signals transmitted between the plurality of detector elements serve to determine a distance of the detector elements from the others of the detector elements in accordance of the time of flight of the known signals, thereby providing information appertaining to a relative distance between the detector elements in the array.
Advantageously the detector elements may further include a data store coupled to the data processor for storing said relative distance data.
Furthermore, each of said detector elements may communicate said predetermined signals to the others of the detector elements thereby generating relative distance data in each of the detector elements appertaining to relative distances to all other detector elements.
The data processors may further operate during a subsequent phase to transmit to the other detector elements via the communicators the relative distance data, and consequent upon receipt of said relative distance data from each of said detector elements, said data processor further operates to generate location data representative of a location of each of the detector elements. The data processor may generate the location data by triangulating the position using the relative distance data for each of the other detector elements.
The term triangulating as used herein refers to and includes a process of determining the relative location of an object from a plurality of distance measurements to that object from a corresponding plurality of reference positions.
By arranging for each of the plurality of detector elements to transmit the relative distance data to all the other detector elements, information appertaining to a respective location of each of the detector elements may be generated for each of the plurality of detector elements, by triangulating the relative location of the detector element from each of the other detector elements.
According to an aspect of the present invention there is provided a method locating a plurality of detector elements, said method comprising the steps of;
arranging for each of said plurality of detector elements to transmit to each of the other detector elements a predetermined signal,
determining at each of the detector elements a temporal difference between a time when said predetermined signal was sent and a time when said predetermined signal was received corresponding to a time of flight of said signals, and
consequent upon said temporal difference from the detector elements to the other detector elements determining a relative distance of the detector element to the other detector elements.
The method of locating said plurality of detector elements, may
further include the steps of;
communicating the relative distances of each of the detector elements between each of the other detector elements, and
for at least one of the detector elements determining the relative location of the plurality of detector elements within the array by triangulating the location using the relative distances from each detector element.
One embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings, wherein;
FIGURE 1 a is a schematic block diagram of a detector element forming part of a detection system,
FIGURE lb is a part aspect view of a detection system,
FIGURE 2 is an aspect view of a plurality of detector elements which appear in Figure lb,
FIGURE 3 is a part aspect view of the plurality of detectors which appear in Figure 2, illustrating transmission of a signal by one of the detector,
FIGURE 4 is a part aspect view of the plurality of detectors which appear in Figure 2, illustrating transmission of a signal by another of the detectors,
FIGURE 5 is a part aspect view of the plurality of detectors which appear in Figure 2, illustrating a part of a triangulation process,
FIGURE 6 is a part aspect view of the plurality detector elements which appear in Figure 2, illustrating a further part of the triangulation process, and
FIGURE 7 is an aspect view of the detection system shown in the preceding Figures detecting a target from signals emitted thereby.
A schematic block diagram of one of a plurality of detector elements which forms part of a detection system is shown in Figure 1 a, with a complete detection system shown in Figure lb. In Figure la, a detector element X, is shown to be comprised of a radio communications transceiver 1, coupled to a control and data processor 2. Coupled to the control and data processor 2, is a data store 3, and a clock 4. The radio transceiver 1, is coupled to an antenna 5, which radiates radio signals generated by the transceiver 4. The detector element X is further provided with a signal sensor 6.
Figure lb, shows a master control unit M, communicating a synchronisation signal carried by radio signals represented as line 8, to each of a plurality of detector elements X which make up the detection system.
On receipt of the synchronisation signal 8, each of the plurality of detector elements X are synchronised with reference to their respective clocks 4.
In use, the detector elements are disposed at unknown and substantially random locations with respect to each other, which is illustrated in the diagram shown in Figure 2, where parts also appearing in
Figure 1 bear like designations. However, as will be explained later, in order for the detector elements to operate in combination to determine the location of a target, the relative location of the detector elements must be established.
In operation each detector element X first determines the relative locations of the other detector elements in the array. A first phase in the determination of the location of the other detector elements is illustrated in
Figure 3.
In Figure 3, there is shown a diagram showing the disposal of detector elements a, b, c, d, e in a substantially random pattern. At a predetermined time one of the detector elements a as shown in Figure 3, is arranged to communicate a chirped signal represented as circles 10, to each of the other of the plurality of detector elements b, c, d, e. Since the emission of the chirped signal from a is arranged to be generated at a predetermined time; and all detector elements 10 are synchronised, the other detector elements in the detection system are arranged to detect the emission of the signal 10. A temporal difference in a time taken to receive the communicated signal 10 from a time when it was sent provides information appertaining to a distance of the first detector a to each corresponding detector element b, c, d, e. This relative distance is calculated in the data processor 2 in each of the detector elements after the predetermined signal has been detected by the radio transceiver 1. The relative distance of a to the detector element is then stored in the data store 3. The chirped signal is de-chirped in the radio transceiver to increase the accuracy with which the time of reception of the signal is determined. The chirped signal alternatively may be a spread spectrum signal, in which case the spectrum of the signal is spread with a known spreading code.
Correspondingly, the process of determining a distance of the detector element b from each of the other detector elements a, c, d, e, is shown in Figure 4, where parts also appearing in Figure 3 bear identical numerical designations. As illustrated, detector element b emits a chirped signal 12 which is detected by each of the other detector elements a, c, d, e.
Since a time of emission of the signal 12 from detector element b is arranged to be effected at a second predetermined time, a distance of b from each of the other plurality of detector elements a, c, d, e, is determined by the data processor 2 in accordance with a time of flight of the signals 12 from b to each of the other detector elements a, c, d, e. Thereafter, this process is repeated in turn by each of the other detector elements, c, d, e, until each detector element is provided with relative distances of all other detector elements.
The distance measurements to each of the other detectors has been illustrated with an example of chirped signals transmitted at separate time intervals by each of the detector elements in turn. However, as will be appreciated, by modulating the radio signals with spreading codes, and using a different code for each detector element, the relative distances can also be determined substantially contemporaneously.
When each detector element has established the relative distance to all other detector elements, the first of the detector elements a, thereafter communicates the relative distance data to each of the other detector elements b, c, d, e appertaining to coded information representative of the distance measurements of each of the other detector elements b, c, d, e with respect to detector a, which has been collected during the first phase. The relative distance data from a is stored in data store 3. This second phase of the process is illustrated in Figure 5, where the circles 14 are representative of the transmission of the relative distance data to each of the other detector elements b, c, d, e. Each of the other detector elements b, c, d, e, are arranged to receive the communication from detector element a, and to decode and store in their data stores 3, data appertaining to the distances of detector elements b, c, d, e, to detector element a. Correspondingly, each of the other detector elements b, c, d, e also effect transmission of the relative distance data collected during the first phase so that each detector element is provided with information appertaining to a relative position of the detector element with respect to the other detector elements in the array. Once the communication of the relative distances have been exchanged between the detector elements, the data processors 2 in each of the detector elements determine the location of all detector elements in the array, by computing a triangulation for each detector element in the array. The process of triangulation is know to those skilled in the art as being a process of solving a set of simultaneous equations in three dimensional space, wherein distances from reference points in the three dimensional space to an object are known, the solution of the set of simultaneous operations being the coordinates of the object in three dimensional space.
To facilitate the process of determining the location of each of the detector elements X, the first three of the detector elements a, b, c are arranged to determine a plane in space from the relative coordinates from each other. This process is illustrated in Figure 5 by the lines 16, 18, 20.
Once the plane defined by the relative coordinates of the detectors a, b, and c have been established, the location of the other detectors in the array may be established. However, as represented in Figure 6, there may be an ambiguity as to the apparent location of other detector elements, in this example, detector d. This is because the data available can be equally consistent with the location of d being below the plane a, b, c as shown in
Figure 6. However, such a distinction is irrelevant since it is only desired to locate the fourth detector element d with respect to the reference plane a, b, c. To provide a further improvement in the location of the detector elements, each detector element may further include apparatus for determining a direction of arrival of the signals, providing a further reference from which the location of detector element may be determined.
In operation the detection system hereinbefore described operates to detect a new object from signals emitted thereby. Each of the plurality of detector elements comprising the detection system is arranged to be provided with a sensor 6, which may detect inter alia acoustic, magnetic, optical or radio signals. This is illustrated in Figure 7, where an object 22, is detected from signals 24 emitted by the object 22, which signals are detected by the signal sensors 6, within each detector element X. The relative position of the new object may be determined from a relative time of arrival of signals generated by that object and detected by the sensors 6, at each of the detector elements X in combination with the relative location of each of the detector elements. From a relative time of arrival of signals at each of the detector elements, the solution as to the location of the object with respect to the detector elements is calculated by any of the data processors within the detector elements.
An improvement in the resolution of the difference in the time of arrival of signals emitted by the object 22 may be effected by cross correlating the signals between the detector elements. In this case each detector element must transmit the signals detected to each of the other detector elements. This again may be effected by arranging for each of the detector elements to transmit the data to each of the other detector elements in a predetermined time plan.
As will be appreciated by those skilled in the art, various modifications may be made to the embodiments hereinbefore described whilst still falling within the scope of the invention. For example the communication of signals between detector elements may be by means other than radio signals, such as acoustic, optical or electrical signals convey by conductors. Furthermore, the detector elements may be further provided with apparatus for determining the direction of arrival of signals emitted by the target, which direction of arrival is used by the data processors to determine the location of the target in combination with the relative time of arrival of the emitted signals.
Claims (14)
- CLAIMS: 1. A detection system comprising a plurality of detector elements which detector elements each include a communicator for communicating data to and from any other of the plurality of detector elements, a data processor coupled to the communicator and arranged in use to send and receive data via the communicator, and a clock coupled to said data processor for providing a temporal reference thereto, wherein said data processor in combination with said communicator of at least one of said detector elements operates to communicate predetermined signals at a predetermined time to other detector elements and consequent upon a temporal difference between said predetermined time and a time of reception of said predetermined signals said data processor operates to generate relative distance data representative of a relative distance of said at least one of said detector elements with respect to said other detector elements.
- 2. A detection system as claimed in Claim 1, wherein the detector elements further include a data store coupled to the data processor for storing said relative distance data.
- 3. A detection system as claimed in Claims 1 or 2, wherein at least one other of said detector elements communicates other predetermined signals to the other elements, and said data processor operates to determine further relative distance data consequent upon a temporal difference between a time of reception and a time of transmission.
- 4. A detection system as claimed in Claims 1, 2 or 3, wherein each detector element has one of said data processors, which operate during a subsequent phase to communicate to the other detector elements via the communicators said relative distance data, and consequent upon receipt of said relative distance data, the data processor of at least one of said detector elements further operates to generate location data representative of a location of the detector elements.
- 5. A detection system as claimed in Claims 4, wherein the data processor generates the location data by triangulating the location using the relative distance data.
- 6. A detection system as claimed in any preceding claim, wherein said predetermined signals are chirped signals.
- 7. A detection system as claimed in any preceding claim, wherein said predetermined signals are modulated using a spreading code, each detector element using a different code.
- 8. A detection system as claimed in any preceding claim, wherein the predetermined signals are separated in time.
- 9. A detection system as claimed in any preceding Claim, wherein each of said detector elements further includes a sensor which operates to detect detection of said radiation in combination with said location data, said detector elements operate to determine the location of said target.
- 10. A detection system as claimed in any preceding claim further including a direction of arrival sensor, which provides said data processor with information appertaining to a direction of arrival of detected signals.
- 11. A method of locating a plurality of detector elements, said method comprising the steps of; arranging for at least one of said plurality of detector elements to transmit to each of the other detector elements predetermined signals, determining at each of detector elements a temporal difference between a time when said predetermined signal was sent and a time when said predetermined signal was received, and consequent upon said temporal difference determining a relative distance of said at least one detector element to said other detector elements.
- 12. A method of locating each of a plurality of detector elements as claimed in Claim 11, wherein further including the steps of; communicating the relative distances of the detector elements with respect to the other detector elements, to each of the other detector elements, and for at least one of the detector elements determining the relative location of the plurality of detector elements from the relative distances of the detector elements from the other detector elements.
- 13. A method of locating each of a plurality of detector elements as claimed in Claim 12, wherein the step of determining the relative location of the plurality of detector elements includes triangulating the location of the detector elements with respect to at least two other detector element in accordance with relative distance therebetween.
- 14. A detection system as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB9720256.8A GB9720256D0 (en) | 1997-09-24 | 1997-09-24 | Detector system |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9800600D0 GB9800600D0 (en) | 1998-03-11 |
| GB2329777A true GB2329777A (en) | 1999-03-31 |
| GB2329777B GB2329777B (en) | 2002-10-02 |
Family
ID=10819532
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB9720256.8A Pending GB9720256D0 (en) | 1997-09-24 | 1997-09-24 | Detector system |
| GB9800600A Expired - Fee Related GB2329777B (en) | 1997-09-24 | 1998-01-14 | Determining the relative positions of detector elements of a detection system |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB9720256.8A Pending GB9720256D0 (en) | 1997-09-24 | 1997-09-24 | Detector system |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB9720256D0 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005033731A1 (en) * | 2003-10-06 | 2005-04-14 | Consejo Superior De Investigaciones Científicas | Pressure-wave-based sensory device which is used to measure the co-ordinates of objects, in particular, objects found during paleo-archaeological excavations |
| US7272404B2 (en) | 2000-02-02 | 2007-09-18 | Nokia Corporation | Position acquisition |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1136359A (en) * | 1966-10-26 | 1968-12-11 | Chisholm John P | Matrix navigation system |
| GB1194470A (en) * | 1967-12-28 | 1970-06-10 | Bendix Corp | Improvements in or relating to an Aircraft Collision Avoidance System |
| GB1250570A (en) * | 1968-03-06 | 1971-10-20 | ||
| US4918609A (en) * | 1988-10-11 | 1990-04-17 | Koji Yamawaki | Satellite-based position-determining system |
| US5194869A (en) * | 1991-07-30 | 1993-03-16 | National Space Development Agency Of Japan | Ranging method using telemetering and apparatus employing said method |
| US5214617A (en) * | 1990-02-21 | 1993-05-25 | The Laitram Corporation | Hydroacoustic ranging system |
| US5321668A (en) * | 1990-02-21 | 1994-06-14 | The Laitram Corporation | Hydroacoustic ranging method using bottom reflections |
| US5491670A (en) * | 1993-01-21 | 1996-02-13 | Weber; T. Jerome | System and method for sonic positioning |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001513891A (en) * | 1997-02-27 | 2001-09-04 | トラクス，インコーポレイテッド | Tracking system for multiple objects in a specific area |
-
1997
- 1997-09-24 GB GBGB9720256.8A patent/GB9720256D0/en active Pending
-
1998
- 1998-01-14 GB GB9800600A patent/GB2329777B/en not_active Expired - Fee Related
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1136359A (en) * | 1966-10-26 | 1968-12-11 | Chisholm John P | Matrix navigation system |
| GB1194470A (en) * | 1967-12-28 | 1970-06-10 | Bendix Corp | Improvements in or relating to an Aircraft Collision Avoidance System |
| GB1250570A (en) * | 1968-03-06 | 1971-10-20 | ||
| US4918609A (en) * | 1988-10-11 | 1990-04-17 | Koji Yamawaki | Satellite-based position-determining system |
| US5214617A (en) * | 1990-02-21 | 1993-05-25 | The Laitram Corporation | Hydroacoustic ranging system |
| US5321668A (en) * | 1990-02-21 | 1994-06-14 | The Laitram Corporation | Hydroacoustic ranging method using bottom reflections |
| US5194869A (en) * | 1991-07-30 | 1993-03-16 | National Space Development Agency Of Japan | Ranging method using telemetering and apparatus employing said method |
| US5491670A (en) * | 1993-01-21 | 1996-02-13 | Weber; T. Jerome | System and method for sonic positioning |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7272404B2 (en) | 2000-02-02 | 2007-09-18 | Nokia Corporation | Position acquisition |
| WO2005033731A1 (en) * | 2003-10-06 | 2005-04-14 | Consejo Superior De Investigaciones Científicas | Pressure-wave-based sensory device which is used to measure the co-ordinates of objects, in particular, objects found during paleo-archaeological excavations |
| ES2229932A1 (en) * | 2003-10-06 | 2005-04-16 | Consejo Sup. De Invest. Cientificas | Pressure-wave-based sensory device which is used to measure the co-ordinates of objects, in particular, objects found during paleo-archaeological excavations |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9720256D0 (en) | 1998-02-11 |
| GB9800600D0 (en) | 1998-03-11 |
| GB2329777B (en) | 2002-10-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20160114 |