GB2350002A - Co-boresighting a tracking sensor and a radar antenna - Google Patents
Co-boresighting a tracking sensor and a radar antenna Download PDFInfo
- Publication number
- GB2350002A GB2350002A GB9910866A GB9910866A GB2350002A GB 2350002 A GB2350002 A GB 2350002A GB 9910866 A GB9910866 A GB 9910866A GB 9910866 A GB9910866 A GB 9910866A GB 2350002 A GB2350002 A GB 2350002A
- Authority
- GB
- United Kingdom
- Prior art keywords
- radar antenna
- antenna
- tracking sensor
- boresight
- radar
- 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
- 238000000034 method Methods 0.000 claims abstract description 23
- 229910052734 helium Inorganic materials 0.000 claims abstract description 4
- 239000001307 helium Substances 0.000 claims abstract description 4
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims abstract description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 239000011888 foil Substances 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims description 2
- 230000001172 regenerating effect Effects 0.000 claims description 2
- 238000000926 separation method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
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
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/86—Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
-
- 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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/40—Means for monitoring or calibrating
- G01S7/4004—Means for monitoring or calibrating of parts of a radar system
- G01S7/4017—Means for monitoring or calibrating of parts of a radar system of HF systems
-
- 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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/40—Means for monitoring or calibrating
- G01S7/4004—Means for monitoring or calibrating of parts of a radar system
- G01S7/4026—Antenna boresight
-
- 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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/40—Means for monitoring or calibrating
- G01S7/4004—Means for monitoring or calibrating of parts of a radar system
- G01S7/4026—Antenna boresight
- G01S7/403—Antenna boresight in azimuth, i.e. in the horizontal plane
-
- 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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/40—Means for monitoring or calibrating
- G01S7/4004—Means for monitoring or calibrating of parts of a radar system
- G01S7/4026—Antenna boresight
- G01S7/4034—Antenna boresight in elevation, i.e. in the vertical plane
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
A method of co-boresighting a radar antenna 21 and a tracking sensor 22 carried by a marine vessel which has a reference 26 mounted on it comprises aligning the boresight of the sensor with the reference, generating a reference radar signal at the reference, encompassing all frequencies at which the radar operates, for aligning the antenna with the reference, then tracking a moving target 25 with both the antenna and sensor and recording the far-field deviation (Figure 4) between their boresights, and finally realigning the boresights to the reference whilst also applying an offset to the boresight of the antenna to account for the far-field deviation. Since the sensor has long range focus a telescope 27 is used to align it with the reference. Preferably the reference is a mast with a target 28 for aligning the sensor and a narrow beam radar generator 24 for aligning the antenna, and is additionally equipped with a mirror 32 to reflect a light source 33 mounted by the antenna to align the orientation of the mast. The mast may also be arranged so that the antenna is pointed towards the sea when boresighted (Figure 5). The moving target may be a metallic helium filled balloon located at 5 km from the vessel.
Description
2350002 IMPROVEMENTS IN OR RELATING TO RADAR ANTENNAE The invention
relates to a method of co-boresighting a radar antenna with an associated tracking sensor and radar antenna and associated tracking sensor apparatus which are both mounted on a marine vessel.
At present a radar antenna is electrically boresighted with a tracking sensor, such as an electro-optical thermo-tracking sensor, by static alignment of the radar antenna and tracking sensor against a distant target on a tower while the marine vessel carrying the radar antenna and tracking sensor is in dry dock. A tower is typically located at a distance of 500 meters from the ship to achieve focus at infinity for the radar antenna.
The technique involves tracking a distant target such as an antenna source located on the tower which is arranged to generate a reference signal that is detectable by both the radar antenna and the tracking sensor and determining the separation between the tracking sensor boresight, which is taken as the reference boresight, and the boresight of the radar antenna. Calibration data is generated which is used with the radar antenna to co boresight the radar antenna and the tracking sensor.
This requires the marine vessel to be in dry dock and the target to be located some 500 meters firom the marine vessel in order to provide focus at infinity. However, as can be seen from Figure 1, this creates a problem, in that the perceived boresight separation, indicated as line labelled 10, between the boresight 11 of a radar antenna 12, and the 2 boresight 13 of a tracking sensor 14 varies with the angle at which the radar antenna 12 and tracking sensor 14 points due to high and low tides affcting location of the marine vessel at dockside. That is the boresight 11 of the radar antenna 12 and the boresight 13 of the tracking sensor 14 varies between boresights indicated as 1 la to 1 lb and 13a to 13b, respectively, with high and low tides. The perceived tracking sensor 14 to radar antenna 12 boresight 13, 11 separation varies with the angle at which the target, not shown, points at the radar antenna 12. This is due to the radar antenna 12 having an antenna phase centre having a significant Z axis component indicated as line labelled 15.
Typically, the antenna phase centre is located approximately two meters in front of tracking sensor 14, this creates an angular pointing error as a result of tidal movement of the marine vessel and the boresight 11 of the radar antenna may, in fact, be indicated as 1 lc rather than 1 lb at low tide.
Furthermore, depending on the radar antenna used, tower and land geotnetries, the simulated target can be contaminated by land or weather clutter and dockyard equipment can cause reflections which interfere with the direct beam between the radar antenna and tower.
It is an object of the invention to obviate or mitigate problems associated with the prior art.
According to a first aspect of the invention, a method of co-boresighting a radar antenna with an associated tracking sensor carried by a marine vessel which also has a reference mounted on the marine vessel comprises aligning the boresight of the tracking sensor 3 with respect to the reference, generating a reference signal associated with the reference for reception by the radar antenna, receiving the reference signal at the radar antenna and modifying calibration data used to correct the boresight of the radar antenna with respect to the boresight of the tracking sensor for frequencies detectable by the radar antenna, then tracking a moving target using both the radar antenna and the tracking sensor and recording the deviation between the boresight of the radar antenna and the boresight of the tracking sensor for frequencies detectable by the radar antenna, then realigning the boresight of the tracking sensor with respect to the reference, regenerating the reference signal for reception by the radar antenna, and receiving the reference signal at the radar antenna and modifying the calibration data whilst also applying an offset signal to the memory in accordance with the inverse of the recorded deviation in boresights, of the radar antenna and the tracking sensor for frequencies detectable by the radar antenna.
is In this manner, the reference is carried on board the vessel and the radar antenna and tracking sensor can be co-boresighted or the calibration data can be assessed while at sea or at dockside and if necessary corrective alignment can be accomplished. Furthermore, the affect of high and low tides on moving the location of the vessel with respect to an alignment target is obviated. It will be understood that the offset signal applied to the memory has the effect of altering the calibration data that would normally be recorded so as to correct the data for the deviation between the boresights of the radar antenna and tracking sensor.
Preferably, the method may include aligning the boresight of the tracking sensor with 4 respect to the reference such that the associated radar antenna has both the reference signal and water in which the vessel is located within its field of view. In this manner the radar antenna perceives the reference signal to appear in water which mitigates clutter caused by land objects or weather conditions within the field of view of the radar antenna.
The method may include generating the reference signal using a reference antenna, mounting the reference antenna to a mast and locating the mast in the field of view of the radar antenna. The method may include aligning the pointing direction of the reference antenna with the radar antenna using a mirror associated with the reference antenna to reflect light from a light source associated with the radar antenna. The method may include mounting the mast on an adjustable mount and aligning the light from the light source associated with the radar antenna with the mirror associated with the reference antenna by moving the mast.
The method may include associating a target with the reference antenna, associating a telescope with the radar antenna and aligning the radar antenna with the reference antenna by viewing the target through the telescope thereby emulating the boresight of the tracking sensor.
Preferably, the method may include positioning the target at a distance from the reference antenna corresponding to the distance between the radar antenna and the telescope.
The method may include producing the reference signal using a narrow beam antenna and a signal generator.
The method may include using a metal foil balloon filled with helium as the moving target.
According to a second aspect of the invention radar antenna and associated tracking sensor apparatus comprises a reference antenna which is arranged to generate a reference signal and which is mounted on a marine vessel carrying the radar antenna and tracking sensor, the radar antenna being arranged to receive the reference signal, a telescope associated with the radar antenna and a target associated with the reference antenna such that when the target is viewed through the telescope the tracking sensor is aligned with the reference antenna, a memory arranged to store calibration data used to correct the boresight of the radar antenna with respect to the boresight of the tracking sensor for frequencies detectable by the radar antenna, and a processor arranged to determine and store the deviation between the boresight of the radar antenna and the boresight of the tracking sensor for frequencies detectable by the radar antenna, whereby the apparatus is operable to correct the boresight of the radar antenna with respect to the boresight of the tracking sensor for frequencies detectable by the radar antenna.
Preferably, the reference antenna is mounted on a mast and the mast is further mounted on the marine vessel.
The invention will now be described, by way of example only, with reference to the 6 accompanying drawings, in which:
Figure 1 illustrates the perceived separation area between a tracking sensor and radar antenna in the prior art;
Figure 2 illustrates apparatus of the present invention; Figure 3 illustrates tracking of a distant object using the tracking sensor and radar antenna, Figure 4 illustrates the calibration offsets necessary to co-boresight the tracking sensor with the radar antenna according the present invention, and Figure 5 illustrates further apparatus of the invention.
From Figures 2 and 3, a marine vessel 20 is arranged to carry a radar antenna 21, for example an I-band radar, and a tracking sensor 22, for example on electro- optical thermal tracking sensor. The radar antenna 21 is mounted to the vessel 20 on a moveable jig 23 such that the radar antenna can be aligned with a reference antenna 24 or arranged to track a moving target 25.
The reference antenna 24 is mounted to the vessel 20 on a mast 26 which is positioned approximately 30 metres in the far field of the radar antenna 21, and the reference antenna 24 is arranged to generate a reference signal to simulate a target which is
7 detectable by the radar antenna 21 for frequencies detectable by the radar antenna 21.
It will be understood that the frequencies detectable by the radar antenna may be a plurality of discrete frequencies within the bandwidth of the radar antenna. The mast can either be temporary or permanent. The reference antenna 24 can be a narrow beam antenna feed by a signal generator.
The tracking sensor 22 cannot focus down to thirty metres while maintaining collimation, therefore the radar antenna 21 has associated with it a telescope 27 and the reference antenna 24 has associated with it a target 28, to accurately emulate the boresight, indicated by dotted line 29, of the tracking sensor 22. The boresight 29 of the tracking sensor 22 is aligned with the reference antenna 24 by viewing the target 28 through the telescope 27. The target 28 may be represented by a cross or another suitable character, or an identifier and the telescope 27 may have crosshairs or other suitable arrangement to aid alignment with the target 28. The spacing between the reference antenna 24 and its associated target 28 and the radar antenna 21 and its associated telescope 27 should be substantially equal.
The radar antenna 21 also has associated with it a memory, not shown, arranged to store digital calibration data which is used to correct the boresight, indicated by dotted line 30, of the radar antenna 21 with respect to the boresight 29 of the tracking sensor 22.
To ensure stability of the boresight 30 of the radar antenna 21, adjustable clamps, not shown, are fitted to the moveable jig 23 so as to mechanically lock the position of the radar antenna 21 in both elevation and azimuth axes. A fine adjustment on these clamps 8 allows the telescope 27 to be aligned with the centre of the target 28. Holding the radar antenna 21 pointing at a stationary target 28, rather than actively tracking a moving target, provides a lower noise level in angle tracking loops used to move the radar antenna 21 thereby improving the final accuracy of the co-boresighting.
Once the boresight 29 of the tracking sensor 22 is aligned with the reference antenna 24, the calibration data stored in the memory is modified, for discrete frequencies, detectable by the radar antenna 21, so as to construct a set of calibration data which corrects the boresight 30 of the radar antenna 21 with respect to the boresight 29 of the tracking sensor 22. Figure 4 illustrates example calibration data as set of points in line labelled X and frequency is indicated along the abscissa.
The radar antenna 21 is released from the mechanical lock and the antenna 21 and tracking sensor 22 are then set to track the moving target 25, which is typically located five kilometres from the vessel 20. The moving target 25 may be a metallic balloon filled with helium which can be released from the vessel 20. From Figure 3, the actual boresight, indicated by solid line 3 1, of the tracking sensor 22 is taken as the reference boresight and a processor, not shown, is arranged to determine and store the deviation between the boresight 30 of the radar antenna 21 and the actual boresight 31 of the tracking sensor 22 for discrete frequencies detectable by the radar antenna 21. The stored deviation produces a set of data points, as indicated in Figure 4, as line labelled Y.
Next, the tracking sensor 22 is again aligned with the reference antenna 24 by viewing 9 the target 28 associated with the reference antenna 24 through the telescope 27 associated with the radar antenna 21 and the mechanical lock applied. The reference signal generated by the reference antenna 24 is again received by the radar antenna 2 1.
Then for discrete frequencies detectable by the radar antenna 21, the inverse of the stored deviation in the processor is applied as an offset signal to the memory whilst the calibration data in the memory is remodified to correct the boresight 30 of the radar antenna 21 for each of those discrete frequencies with respect to the boresight 29 of the tracking sensor 22. It will be understood that the stored deviation can be converted into an offset signal which is added into the angle tracking loops used to control the radar antenna 21 so as to cause the calibration data to be offset by an amount equal to the applied offset signal. In this manner, the boresight 30 of the radar antenna is co boresighted with the boresight 29 generated by the tracking sensor 22 in such a manner so as to offset for electrical deviations in the expected boresights of the radar antenna 21 and tracking sensor 22.
It will be understood that boresights labelled 29 and 31 in Figures 2 and 3 are in affect the same boresight generated by either the telescope 27 and target 28, to emulate the boresight of the tracking sensor 22 as it cannot focus down to thrity metres, or by the tracking sensor 22 itself, at ranges above thirty metres. The modified calibration data is illustrated as set of data points labelled line Z in Figure 4.
The pointing direction of the reference antenna 24 with respect to the radar antenna 21 is important and, as can be seen in Figure 2, the accuracy can be determined by mounting a mirror 32 on the mast to reflect light from a fight source 33 associated with the radar antenna 21. The mast 26 can be fitted on an adjustable mount to allow pointing inaccuracies to be corrected.
In a further embodiment, shown in Figure 5, a vessel 40 is arranged to carry a radar antenna 41 and a tracking sensor 42. The radar antenna 41 is mounted on a moveable jig, not shown, such that the radar antenna 41 can be aligned with a reference antenna 43, mounted on a mast 44, used to generate a reference signal, to simulate a target, which is detectable by the radar antenna 4 1. The boresight, indicated by dotted line 45, of the radar antenna 41 is arranged to align with the reference antenna 43 such that the reference signal appears in water 46 about the vessel 40. This mitigates clutter caused by land objects or weather conditions within the field of view of the radar antenna 41.
The co-boresighting technique is substantially the same as that already described with reference to Figures 2 to 4.
In this manner accuracy in co-boresighting can be greater than 1.6 metres at 10 kilometres or 0.5 arcminutes.
Claims (13)
1. A method of co-boresighting a radar antenna with an associated tracking sensor carried by a marine vessel which also has a reference mounted on the marine vessel, comprising aligning the boresight of the tracking sensor with respect to the reference, generating a reference signal associated with the reference for reception by the radar antenna, receiving the reference signal at the radar antenna and modifying calibration data used to correct the boresight of the radar antenna with respect to the boresight of the tracking sensor for frequencies detectable by the radar antenna, then tracking a moving target using both the radar antenna and the tracking sensor and recording the deviation between the boresight of the radar antenna and the boresight of the tracking sensor for frequencies detectable by the radar antenna, then realigning the boresight of the tracking sensor with respect to the reference, regenerating the reference signal for reception by the radar antenna, and 12 receiving the reference signal at the radar antenna and modifying the calibration data whilst also applying an offset signal to the memory in accordance with the inverse of the recorded deviation in the boresights of the radar antenna and the tracking sensor for frequencies detectable by the radar antenna.
2. A method, as in Claim 1, including generating the reference signal using a reference antenna, mounting the reference antenna to a mast and locating the mast in the field of view of the radar antenna.
3. A method, as in Claims 1 or 2, including aligning the boresight of the tracking sensor with respect to the reference such that the associated radar antenna has both the reference signal and water in which the vessel is located within its field of view.
4. A method, as in Claims 2 or 3, including aligning the pointing direction of the reference antenna with the radar antenna using a mirror associated with the reference antenna to reflect light from a light source associated with the radar antenna.
5. A method, as in Claim 4, including mounting the mast on an adjustable mount and aligning the light from the light source associated with the radar antenna with the mirror associated with the reference antenna by moving the mast.
6. A method, as in Claims 2 to 5, including associating a target with the reference 13 antenna, associating a telescope with the radar antenna and aligning the radar antenna with the reference antenna by viewing the target through the telescope thereby emulating the boresight of the tracking sensor.
7. A method, as in Claim 6, including positioning the target at a distance from the reference antenna corresponding to the distance between the radar antenna and. the telescope.
8. A method, as in Claim 2 to 7, including producing the reference signal using a narrow beam antenna and a signal generator.
9. A method, as in any preceding claim, including using a metal foil balloon filled with helium as the moving target.
10. A method substantially as illustrated in and/or described with reference to the accompanying drawings.
11. Radar antenna and associated tracking sensor apparatus, comprising a reference antenna which is arranged to generate a reference signal and which is mounted on a marine vessel carrying the radar antenna and tracking sensor, the radar antenna being arranged to receive the reference signal, 14 a telescope associated with the radar antenna and a target associated with the reference antenna such that when the target is viewed through the telescope the tracking sensor is aligned with the reference antenna, a memory arranged to store calibration data used to correct the boresight of the radar antenna with respect to the boresight of the tracking sensor for frequencies detectable by the radar antenna, and a processor arranged to determine and store the deviation between the boresight of the radar antenna and the boresight of the tracking sensor for frequencies detectable by the radar antenna, whereby the apparatus is operable to correct the boresight of the radar antenna with respect to the boresight of the tracking sensor for frequencies detectable by the radar antenna.
12. Radar antenna and associated tracking sensor apparatus, as in Claim 11, wherein the reference antenna is mounted on a mast and the mast is further mounted on the marine vessel.
13. Radar antenna and tracking sensor apparatus substantially as illustrated in and/or described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9910866A GB2350002B (en) | 1999-05-12 | 1999-05-12 | Improvements in or relating to radar antennae |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9910866A GB2350002B (en) | 1999-05-12 | 1999-05-12 | Improvements in or relating to radar antennae |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9910866D0 GB9910866D0 (en) | 1999-07-07 |
| GB2350002A true GB2350002A (en) | 2000-11-15 |
| GB2350002B GB2350002B (en) | 2003-11-19 |
Family
ID=10853199
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9910866A Expired - Fee Related GB2350002B (en) | 1999-05-12 | 1999-05-12 | Improvements in or relating to radar antennae |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2350002B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2897442A1 (en) * | 2006-02-13 | 2007-08-17 | Marc Brussieux | Intrusion detection device for e.g. coastal area, has coordination unit to coordinate detection unit with information so that detection axis is pointed towards intruder, and control unit to control pointing of axis on position of intruder |
| WO2018158502A1 (en) * | 2017-02-28 | 2018-09-07 | Rolls-Royce Oy Ab | Apparatus and system for assessing or measuring the capability of situational awareness sensors |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0247375A2 (en) * | 1986-05-28 | 1987-12-02 | Atlas Elektronik Gmbh | Method for locating an under water target |
| GB2213339A (en) * | 1987-12-02 | 1989-08-09 | Secr Defence | Relative position determination |
| EP0362914A2 (en) * | 1988-09-16 | 1990-04-11 | Hollandse Signaalapparaten B.V. | Surveillance radar |
| GB2318010A (en) * | 1996-10-07 | 1998-04-08 | Secr Defence | Reflecting transponder for calibrating phased-array radar |
-
1999
- 1999-05-12 GB GB9910866A patent/GB2350002B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0247375A2 (en) * | 1986-05-28 | 1987-12-02 | Atlas Elektronik Gmbh | Method for locating an under water target |
| GB2213339A (en) * | 1987-12-02 | 1989-08-09 | Secr Defence | Relative position determination |
| EP0362914A2 (en) * | 1988-09-16 | 1990-04-11 | Hollandse Signaalapparaten B.V. | Surveillance radar |
| GB2318010A (en) * | 1996-10-07 | 1998-04-08 | Secr Defence | Reflecting transponder for calibrating phased-array radar |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2897442A1 (en) * | 2006-02-13 | 2007-08-17 | Marc Brussieux | Intrusion detection device for e.g. coastal area, has coordination unit to coordinate detection unit with information so that detection axis is pointed towards intruder, and control unit to control pointing of axis on position of intruder |
| WO2018158502A1 (en) * | 2017-02-28 | 2018-09-07 | Rolls-Royce Oy Ab | Apparatus and system for assessing or measuring the capability of situational awareness sensors |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9910866D0 (en) | 1999-07-07 |
| GB2350002B (en) | 2003-11-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20140512 |