EP2329290A1 - High frequency surfacewave radar - Google Patents
High frequency surfacewave radarInfo
- Publication number
- EP2329290A1 EP2329290A1 EP09807959A EP09807959A EP2329290A1 EP 2329290 A1 EP2329290 A1 EP 2329290A1 EP 09807959 A EP09807959 A EP 09807959A EP 09807959 A EP09807959 A EP 09807959A EP 2329290 A1 EP2329290 A1 EP 2329290A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- antenna
- antenna element
- frequency
- array
- range
- 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.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
- H01Q9/04—Resonant antennas
- H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
- H01Q9/28—Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines
-
- 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
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/0218—Very long range radars, e.g. surface wave radar, over-the-horizon or ionospheric propagation systems
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
- H01Q19/28—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using a secondary device in the form of two or more substantially straight conductive elements
- H01Q19/30—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using a secondary device in the form of two or more substantially straight conductive elements the primary active element being centre-fed and substantially straight, e.g. Yagi antenna
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q21/00—Antenna arrays or systems
- H01Q21/28—Combinations of substantially independent non-interacting antenna units or systems
Definitions
- the present invention relates to a high frequency surfacewave radar (HFSWR) installation.
- HFSWR high frequency surfacewave radar
- Conventional HFSWR transmits an RF signal at a single frequency and detects energy which is returned from objects in the path of the transmitted RF signal.
- the range of HFSWR is significantly enhanced over standard ground - based radar in that the range to a surface target that might be detected is in the order of hundreds of kilometres.
- the frequency range associated with high frequency radar is approximately 3-30 MHz and the corresponding wavelength of the transmitted signal is measured in tens of meters, say 10m to 100m.
- the wavelength of the signal to be transmitted directly governs the size of an associated transmitting antenna element. The magnitude of a HFSWR installation comprising a number of such antenna elements in an array can therefore be significant.
- log-periodic antennae In order to achieve reasonable coverage across the HF frequency range, it is known to provide a transmit array comprising one or more log-periodic antennae.
- log-periodic antennae whilst log-periodic antennae are naturally able to operate over a particularly wide band, they are not regarded as being physically stable and correspondingly robust and can, therefore, be disadvantageous.
- HFSWR single frequency HFSWR are limited in their performance due to external influences such as man made interference, for example radio transmissions. Consequently, such HFSWR are considered to be “external noise” limited as these external signals dominate any internal noise levels of the internal mechanism such as receive electronics of the radar installation.
- Alternative radar, such as those operating at microwave frequencies, are typically “internal noise” limited as the noise generated by the internal mechanism of the radar dominate any external noise signals at microwave frequencies. It is an aim of the present invention to address the aforementioned disadvantages associated with High Frequency Surfacewave Radar and alleviate some of the problems coupled therewith.
- the present invention provides a high frequency surfacewave radar installation comprising an array of antenna elements, the array comprising: a first antenna element configured to exhibit a first characteristic; and a second antenna element configured to exhibit a second characteristic, related to the first characteristic but different therefrom.
- the first antenna element may be a doublet capable of directional transmission and/or reception and the second antenna element may be a single monopole or dipole capable of omnidirectional transmission and/or reception.
- the doublet may comprise monopole or dipole elements.
- the first antenna element may be configured to transmit a signal having a frequency in the range of a first octave and the second antenna element may be configured to transmit a signal having a frequency in the range of a second octave.
- the first and second antenna elements may be doublets capable of directional transmission and/or reception and the array may comprise a third antenna element, wherein the third element may be a single monopole or dipole capable of omnidirectional transmission and/or reception.
- the present invention provides a high frequency surfacewave radar installation comprising an array of antenna elements, the array comprising: a first antenna element configured to transmit a signal having a frequency in the range of a first octave; and a second antenna element configured to transmit a signal having a frequency in the range of a second octave.
- first and second antenna elements each having capability for transmitting in different octaves of frequency
- a compact antenna installation having an extended bandwidth can be achieved.
- the second antenna element may be smaller than the first antenna element.
- the first octave may represent a range of up to 8 MHz and the second octave may represent a range from 8 to 16 MHz.
- the array may comprise a third antenna element configured to transmit a signal having a frequency in the range of a third octave.
- the third antenna element may be smaller than the second antenna element and the third octave may represent a range above 16 MHz.
- the antenna elements may be configured to receive a signal on any frequency covered by the transmission from the radar installation.
- radar installation we mean an installation capable of transmitting and/or receiving radar signals from one or more antennae together with the corresponding electronics for operating the, or each, antenna.
- antenna we mean apparatus comprising an array of antenna elements.
- an “array” of antenna elements we mean a number of, potentially different, antenna elements, regularly or irregularly spaced the output of which are combined in some manner.
- FIG. 1 illustrates an antenna
- Figure 2 illustrates a schematic representation of an architecture of the antenna of Figure 1 ;
- Figure 3 illustrates a schematic representation of an alternative antenna
- FIG 4 illustrates a schematic representation of another alternative antenna.
- the antenna 10 illustrated in Figure 1 comprises an array of antenna elements 15a, 15b, 15c, 15d, 15e, 15f.
- each element is represented by a doublet.
- Each doublet comprises a pair of tetrahedral dipoles in a conventional manner.
- the phase relationship between the two dipoles reinforces forward transmission of a signal whilst reducing backward transmission of the signal hence providing directionality of the antenna element.
- the extent of this reinforcement is denoted by the 'front to back ratio' of a particular doublet configuration and the configuration is chosen to achieve a particular result. In this embodiment, the front to back ratio is approximately 15 dB.
- the antenna 20 comprises an array of sixteen elements, up to six of which, hereinafter referred to as transmitting elements 25a-25f, may be used when the antenna 20 is transmitting as illustrated in Figure 2a and all of which may be used when the antenna 20 is receiving as illustrated in Figure 2b.
- the six transmit elements 25a-25f are each capable of transmission and reception using duplexer units which comprise both a transmission port and a receive port.
- the transmit elements each comprise a doublet and has associated therewith a digital waveform generator 30 and an amplifier 35.
- the amplifier is a 1 kW solid state power amplifier.
- a controller 40 is provided to supply instructions to the waveform generator 30, the amplifier 35 and the antenna 20.
- transmit elements 25a-25f may all be used in combination to transmit an outgoing signal or, alternatively a reduced number, even a single element, may be used to transmit the outgoing signal.
- the number and configuration of elements used to transmit affects the form of signal generated thereby.
- a focused beam having high gain is output in a plane normal to the plane of the array.
- a wider beam, of lower gain can be achieved by using a single element to output the transmission signal.
- Phase ramps or weighting can be implemented across the array in order to achieve an electronic beam steering capability.
- a single frequency can be transmitted by any particular element.
- multiple carrier frequencies can be generated within the waveform to enable more than one frequency to be transmitted by the, or each, element at any one time.
- Transmit signals are generated by the digital waveform generator 30 associated with each element.
- the waveform generators are fully controlled by software.
- the software replicates analogue production of one or more signals and generates parallel streams of data having multiple frequency content. Such a signal represents a number of independent signals, each having a different transmission frequency.
- the waveform characteristics for each element are independent, fully programmable and arbitrary. In other words, the generation of simultaneous, multiple frequency and beam combinations is enabled on transmission from the antenna 20.
- Figure 2b illustrates operation of antenna 20 in a receive mode.
- the antenna 20 comprises a plurality of elements 42a-42j in addition to the aforementioned transmit elements 25a-25f. Each element 25a-25f, 42a-42j is capable of receiving incoming signals.
- each element 25a-25f, 42a-42j is provided with its own dedicated receiver 45, capable of simultaneous receipt and detection of signals having up to four frequencies.
- the receiver is configured to receive the incoming signal which, as described above, may have multiple frequency content. This incoming signal is then digitised and discretised into the separate detected independent signals and passed to controller 40 for signal processing.
- simultaneous receive beam forming is preferably used across the entire array so that electronic beam steering may be used to detect targets in particular directions.
- One element, say doublet 42a, is configured with reverse phasing to act as a Rear Lobe Blanking (RLB) antenna.
- Another of the elements 42j serves as an environmental monitoring antenna in addition to being part of the antenna array 20.
- each antenna element is provided by a doublet, i.e. a pair of cooperating dipoles.
- doublets In using doublets exclusively the size and cost of the antenna array 20 may become significant. It is desirable to reduce the complexity and magnitude of the array.
- those antenna elements used solely for receiving signals, elements 42b-42j may comprise single dipoles 42' rather than doublets 42 as exemplified in the antenna array
- each antenna element may comprise one or more monopole antenna elements, preferably comprising a tetrahedral element.
- Use of a monopole antenna element requires appropriate ground conditions or use of an antenna mat, but if such conditions are available, the reduced magnitude associated with the monopole leads to advantageously reduced material and installation costs.
- the functionality of the antenna 10 is further expanded.
- Conventional radar operate in a relatively narrow frequency band.
- the apparatus described in the aforementioned embodiment is substantially independent of the operating frequency except in terms of the geometry presented by each antenna element. In particular, it is the height of the dipole that determines the frequency that can be transmitted therefrom.
- Each tetrahedral dipole forming the antenna array 20 for the first embodiment stands approximately 8m high.
- the distance, d, between each tetrahedral dipole of a doublet is approximately 6m [ ⁇ /4].
- the distance, D, between adjacent doublets is approximately ⁇ /2 [10-12m] thus the antenna array 20 is approximately 200 m long. This magnitude of array is required in order to achieve a spacing through which signals can be received and processed to yield quantifiable data.
- the tetrahedral dipole configuration exhibits a greater frequency range than say a conventional monopole or dipole, the range is still limited to a single octave, for example 8-16 MHz.
- the duplexer unit associated with each doublet leads to some inherent restrictions in the device, however the primary restriction of the device is in the physical dimensions, particularly the height, of the dipole itself.
- dipoles having a different physical magnitude may be introduced into the antenna array. To achieve a higher frequency, a smaller sized dipole may be provided.
- Figure 3 illustrates how dipoles (or other antenna elements) of two different sizes can be interlaced with one another in order to achieve two octaves of coverage.
- Eight elements 50 to 56 and 60 to 66 are used for transmission and reception whilst the remainder of the elements 70 are used only to receive signals. As illustrated, each element is provided by a doublet.
- the larger elements 50, 52, 54, 56 transmit on lower frequencies F1 , F2, F3, F4, say in the range from 4-8 MHz. Meanwhile, the smaller elements 60, 62, 64, 66 transmit at frequencies F5, F6, F7, F8 in a higher frequency range, say in the range 8-16 MHz.
- Antenna elements having an active tuning capability can be used in place of elements having a different physical magnitude. Such elements are particularly effective on receive where efficiency is less critical.
- three sizes of dipole could be interspersed with one another in order to achieve an installation covering three octaves.
- the larger elements 80, 82, 84, 86 transmit on lower frequencies F1 , F2,
- F3, F4 say in the range from 4-8 MHz.
- the medium sized elements 90, 92, 94, 96 transmit at frequencies F5, F6, F7, F8 in a higher frequency range, say 8-16MHz.
- the smallest elements 100, 102, 104, 106 transmit at the highest end of the "high frequency" band, say in the range 16-30MHz.
- aircraft targets could be located anywhere and so the directionality afforded by the doublet arrangement is required.
- higher frequencies are required and so the physical magnitude of each dipole is reduced.
- the antennae discussed above each represent a monostatic architecture, whereby the transmit antenna and the receive antenna are collocated.
- the aforementioned principals can readily be applied to a bistatic architecture, whereby the transmit antenna is located remotely from the receive antenna, or in a multistatic architecture where one or more remotely located additional antennae are provided.
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Variable-Direction Aerials And Aerial Arrays (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
A high frequency surfacewave radar installation is provided comprising an array of antenna elements. The array comprises a first antenna element which is configured to transmit a signal having a frequency in the range of a first octave together with a second antenna element which is configured to transmit a signal having a frequency in the range of a second octave.
Description
HIGH FREQUENCY SURFACEWAVE RADAR
The present invention relates to a high frequency surfacewave radar (HFSWR) installation.
Conventional HFSWR transmits an RF signal at a single frequency and detects energy which is returned from objects in the path of the transmitted RF signal.
The range of HFSWR is significantly enhanced over standard ground - based radar in that the range to a surface target that might be detected is in the order of hundreds of kilometres. The frequency range associated with high frequency radar is approximately 3-30 MHz and the corresponding wavelength of the transmitted signal is measured in tens of meters, say 10m to 100m. The wavelength of the signal to be transmitted directly governs the size of an associated transmitting antenna element. The magnitude of a HFSWR installation comprising a number of such antenna elements in an array can therefore be significant.
In order to achieve reasonable coverage across the HF frequency range, it is known to provide a transmit array comprising one or more log-periodic antennae. However, whilst log-periodic antennae are naturally able to operate over a particularly wide band, they are not regarded as being physically stable and correspondingly robust and can, therefore, be disadvantageous.
Conventional, single frequency HFSWR are limited in their performance due to external influences such as man made interference, for example radio transmissions. Consequently, such HFSWR are considered to be "external noise" limited as these external signals dominate any internal noise levels of the internal mechanism such as receive electronics of the radar installation. Alternative radar, such as those operating at microwave frequencies, are typically "internal noise" limited as the noise generated by the internal mechanism of the radar dominate any external noise signals at microwave frequencies.
It is an aim of the present invention to address the aforementioned disadvantages associated with High Frequency Surfacewave Radar and alleviate some of the problems coupled therewith.
According to a first aspect, the present invention provides a high frequency surfacewave radar installation comprising an array of antenna elements, the array comprising: a first antenna element configured to exhibit a first characteristic; and a second antenna element configured to exhibit a second characteristic, related to the first characteristic but different therefrom. By providing an antenna installation having an array of antenna elements of differing configurations to achieve alternative characteristics, a compact antenna installation having greater functionality can be achieved.
The first antenna element may be a doublet capable of directional transmission and/or reception and the second antenna element may be a single monopole or dipole capable of omnidirectional transmission and/or reception. The doublet may comprise monopole or dipole elements. By combining different types of antenna element the overall magnitude of the antenna installation may be optimised and by using antenna elements comprising monopole or dipole elements (e.g. tetrahedral elements), a physically stable and, therefore, robust antenna array is achieved.
Alternatively the first antenna element may be configured to transmit a signal having a frequency in the range of a first octave and the second antenna element may be configured to transmit a signal having a frequency in the range of a second octave. In which case, a compact installation having a significantly extended bandwidth may be achieved. The first and second antenna elements may be doublets capable of directional transmission and/or reception and the array may comprise a third antenna element, wherein the third element may be a single monopole or dipole capable of omnidirectional transmission and/or reception. By providing of one or more antenna elements having a single monopole or dipole configuration, the overall magnitude of an antenna installation having an extended band width may be optimised.
According to a second aspect, the present invention provides a high frequency surfacewave radar installation comprising an array of antenna elements, the array comprising: a first antenna element configured to transmit a signal having a frequency in the range of a first octave; and a second antenna element configured to transmit a signal having a frequency in the range of a second octave.
By providing first and second antenna elements each having capability for transmitting in different octaves of frequency, a compact antenna installation having an extended bandwidth can be achieved.
The second antenna element may be smaller than the first antenna element.
The first octave may represent a range of up to 8 MHz and the second octave may represent a range from 8 to 16 MHz. The array may comprise a third antenna element configured to transmit a signal having a frequency in the range of a third octave. The third antenna element may be smaller than the second antenna element and the third octave may represent a range above 16 MHz.
The antenna elements may be configured to receive a signal on any frequency covered by the transmission from the radar installation.
In this application, by the phrase "radar installation" we mean an installation capable of transmitting and/or receiving radar signals from one or more antennae together with the corresponding electronics for operating the, or each, antenna. By "antenna" we mean apparatus comprising an array of antenna elements.
By an "array" of antenna elements we mean a number of, potentially different, antenna elements, regularly or irregularly spaced the output of which are combined in some manner.
The present invention will now be described in detail, with reference to the accompanying drawings, in which;
Figure 1 illustrates an antenna;
Figure 2 illustrates a schematic representation of an architecture of the antenna of Figure 1 ;
Figure 3 illustrates a schematic representation of an alternative antenna; and
Figure 4 illustrates a schematic representation of another alternative antenna. The antenna 10 illustrated in Figure 1 comprises an array of antenna elements 15a, 15b, 15c, 15d, 15e, 15f. In this configuration each element is represented by a doublet. Each doublet comprises a pair of tetrahedral dipoles in a conventional manner. By providing the dipoles in pairs, each doublet is able to generate and transmit a directional signal. The phase relationship between the two dipoles reinforces forward transmission of a signal whilst reducing backward transmission of the signal hence providing directionality of the antenna element. The extent of this reinforcement is denoted by the 'front to back ratio' of a particular doublet configuration and the configuration is chosen to achieve a particular result. In this embodiment, the front to back ratio is approximately 15 dB.
The spacing, d, between dipoles in any doublet of the array is approximately a quarter of the wavelength (i.e. d=λ/4) and the spacing, D, between each adjacent doublet in the array is approximately half the wavelength (D= λ 12). Figure 2 illustrates a schematic representation of an example antenna
20. The antenna 20 comprises an array of sixteen elements, up to six of which, hereinafter referred to as transmitting elements 25a-25f, may be used when the antenna 20 is transmitting as illustrated in Figure 2a and all of which may be used when the antenna 20 is receiving as illustrated in Figure 2b. The six transmit elements 25a-25f are each capable of transmission and reception using duplexer units which comprise both a transmission port and a receive
port. The transmit elements each comprise a doublet and has associated therewith a digital waveform generator 30 and an amplifier 35. In this example, the amplifier is a 1 kW solid state power amplifier. A controller 40 is provided to supply instructions to the waveform generator 30, the amplifier 35 and the antenna 20.
Of the six transmit elements 25a-25f, they may all be used in combination to transmit an outgoing signal or, alternatively a reduced number, even a single element, may be used to transmit the outgoing signal. The number and configuration of elements used to transmit affects the form of signal generated thereby.
If all the elements 25a-25f transmit simultaneously in phase with one another, a focused beam having high gain is output in a plane normal to the plane of the array. A wider beam, of lower gain, can be achieved by using a single element to output the transmission signal. Phase ramps or weighting can be implemented across the array in order to achieve an electronic beam steering capability.
A single frequency can be transmitted by any particular element. Alternatively, multiple carrier frequencies can be generated within the waveform to enable more than one frequency to be transmitted by the, or each, element at any one time.
Transmit signals are generated by the digital waveform generator 30 associated with each element. The waveform generators are fully controlled by software. The software replicates analogue production of one or more signals and generates parallel streams of data having multiple frequency content. Such a signal represents a number of independent signals, each having a different transmission frequency. The waveform characteristics for each element are independent, fully programmable and arbitrary. In other words, the generation of simultaneous, multiple frequency and beam combinations is enabled on transmission from the antenna 20. Figure 2b illustrates operation of antenna 20 in a receive mode. The antenna 20 comprises a plurality of elements 42a-42j in addition to the
aforementioned transmit elements 25a-25f. Each element 25a-25f, 42a-42j is capable of receiving incoming signals.
In this example, each element 25a-25f, 42a-42j is provided with its own dedicated receiver 45, capable of simultaneous receipt and detection of signals having up to four frequencies. The receiver is configured to receive the incoming signal which, as described above, may have multiple frequency content. This incoming signal is then digitised and discretised into the separate detected independent signals and passed to controller 40 for signal processing.
The processing required to perform this discretisation relies on the knowledge that four particular distinct signals are being received on four known frequencies.
On receipt, simultaneous receive beam forming is preferably used across the entire array so that electronic beam steering may be used to detect targets in particular directions. One element, say doublet 42a, is configured with reverse phasing to act as a Rear Lobe Blanking (RLB) antenna. Another of the elements 42j serves as an environmental monitoring antenna in addition to being part of the antenna array 20.
In the aforementioned embodiments each antenna element is provided by a doublet, i.e. a pair of cooperating dipoles. In using doublets exclusively the size and cost of the antenna array 20 may become significant. It is desirable to reduce the complexity and magnitude of the array. In a signal transmission mode it is desirable to transmit the signal directionally however, in a reception mode directionality becomes less critical and, therefore, those antenna elements used solely for receiving signals, elements 42b-42j, may comprise single dipoles 42' rather than doublets 42 as exemplified in the antenna array
20' shown in Figure 2c. In so doing, the number of components in each receive antenna element is halved thus reducing the material costs, the installation costs and maintenance associated therewith. Furthermore, each antenna element may comprise one or more monopole antenna elements, preferably comprising a tetrahedral element. Use of a monopole antenna element requires
appropriate ground conditions or use of an antenna mat, but if such conditions are available, the reduced magnitude associated with the monopole leads to advantageously reduced material and installation costs.
In a more sophisticated embodiment, the functionality of the antenna 10 is further expanded. Conventional radar operate in a relatively narrow frequency band. However, the apparatus described in the aforementioned embodiment is substantially independent of the operating frequency except in terms of the geometry presented by each antenna element. In particular, it is the height of the dipole that determines the frequency that can be transmitted therefrom.
Each tetrahedral dipole forming the antenna array 20 for the first embodiment stands approximately 8m high. The distance, d, between each tetrahedral dipole of a doublet is approximately 6m [λ/4]. The distance, D, between adjacent doublets is approximately λ/2 [10-12m] thus the antenna array 20 is approximately 200 m long. This magnitude of array is required in order to achieve a spacing through which signals can be received and processed to yield quantifiable data.
Whilst the tetrahedral dipole configuration exhibits a greater frequency range than say a conventional monopole or dipole, the range is still limited to a single octave, for example 8-16 MHz. The duplexer unit associated with each doublet leads to some inherent restrictions in the device, however the primary restriction of the device is in the physical dimensions, particularly the height, of the dipole itself. In order to cover a greater frequency (i.e. a wider bandwidth) dipoles having a different physical magnitude may be introduced into the antenna array. To achieve a higher frequency, a smaller sized dipole may be provided.
Figure 3 illustrates how dipoles (or other antenna elements) of two different sizes can be interlaced with one another in order to achieve two octaves of coverage.
Eight elements 50 to 56 and 60 to 66 are used for transmission and reception whilst the remainder of the elements 70 are used only to receive signals. As illustrated, each element is provided by a doublet.
The larger elements 50, 52, 54, 56 transmit on lower frequencies F1 , F2, F3, F4, say in the range from 4-8 MHz. Meanwhile, the smaller elements 60, 62, 64, 66 transmit at frequencies F5, F6, F7, F8 in a higher frequency range, say in the range 8-16 MHz.
A high level of power must be provided to each transmit element of the antenna, however, whilst efficiency is of concern during transmit it is less important on receipt. Consequently, the remainder of the smaller elements 70 can be used to receive the low frequency signals in addition to the higher frequency signals as the doublet of each respective element are able to receive all frequencies although some losses will occur.
Antenna elements having an active tuning capability can be used in place of elements having a different physical magnitude. Such elements are particularly effective on receive where efficiency is less critical.
In a more sophisticated embodiment, illustrated in Figure 4, three sizes of dipole could be interspersed with one another in order to achieve an installation covering three octaves. In this example, twelve antenna elements 80 to 86, 90 to 96 and 100 to
106 are used for transmission and reception whilst the remainder of the elements 1 10 are only used to receive signals.
The larger elements 80, 82, 84, 86 transmit on lower frequencies F1 , F2,
F3, F4, say in the range from 4-8 MHz. Meanwhile, the medium sized elements 90, 92, 94, 96 transmit at frequencies F5, F6, F7, F8 in a higher frequency range, say 8-16MHz. The smallest elements 100, 102, 104, 106 transmit at the highest end of the "high frequency" band, say in the range 16-30MHz.
By using an increased frequency range, a more comprehensive surveillance picture can be collated. In particular, alternative traces can be considered and compared when clutter is present, in order to ascertain the
location of a target. In this way, reflections due to clutter can more effectively be eliminated and targets otherwise occluded can be detected.
Further design selections can be made in order to minimise/optimise the magnitude and cost of an antenna installation, especially where a particular target type is envisaged. For example, ships are large, slow moving targets that require lower frequencies to be used. This suggests that larger antenna elements ought to be employed. However, if the transmission array is land based, it is likely that the general direction of the anticipated targets is known (i.e. out to sea) and therefore the doublet arrangement for each antenna element is not required as the directionality associated therewith is redundant. Consequently, although the magnitude of each transmitting dipole is large to provide an accurate, low frequency signal. Each element need only comprise a single dipole rather than a doublet, thus halving the magnitude of the element.
In contrast, aircraft targets could be located anywhere and so the directionality afforded by the doublet arrangement is required. However, due to the speed and magnitude of the target type, higher frequencies are required and so the physical magnitude of each dipole is reduced.
The antennae discussed above each represent a monostatic architecture, whereby the transmit antenna and the receive antenna are collocated. The aforementioned principals can readily be applied to a bistatic architecture, whereby the transmit antenna is located remotely from the receive antenna, or in a multistatic architecture where one or more remotely located additional antennae are provided.
Claims
1. A high frequency surfacewave radar installation comprising an array of antenna elements, the array comprising: a first antenna element configured to exhibit a first characteristic; and a second antenna element configured to exhibit a second characteristic, related to the first characteristic but different therefrom.
2. An installation according to Claim 1 , wherein the first antenna element is a doublet capable of directional transmission and/or reception and the second antenna element is a single monopole or dipole capable of omnidirectional transmission and/or reception.
3. An installation according to Claim 1 , wherein the first antenna element is configured to transmit a signal having a frequency in the range of a first octave and the second antenna element is configured to transmit a signal having a frequency in the range of a second octave.
4. An installation according to Claim 3, wherein the first and second antenna elements are doublets capable of directional transmission and/or reception and wherein the array comprises a third antenna element, the third element being a single monopole or dipole capable of omnidirectional transmission and/or reception.
5. An installation according to any preceding claim, wherein the, or each, antenna element comprises a tetrahedral element.
6. A high frequency surfacewave radar installation comprising an array of antenna elements, the array comprising: a first antenna element configured to transmit a signal having a frequency in the range of a first octave; and a second antenna element configured to transmit a signal having a frequency in the range of a second octave.
7. An installation according to any of Claims 3, to 6, wherein the second antenna element is smaller than the first antenna element.
8. An installation according to any of Claims 3 to 7, wherein the first octave represents a range of up to 8 MHz.
9. An installation according to any of Claims 3 to 8, wherein the second octave represents a range from 8 to 16 MHz.
10. An installation according to any of Claims 3 to 9, wherein the array comprises a third antenna element configured to transmit a signal having a frequency in the range of a third octave
11. An installation according to Claim 10, wherein the third antenna element is smaller than the second antenna element.
12. An installation according to Claim 10 or Claim 11 , wherein the third octave represents a range above 16 MHz.
13. An installation according to any preceding claim, wherein the antenna elements are configured to receive a signal on any frequency covered by the transmission from the radar installation.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP09807959A EP2329290A1 (en) | 2008-08-20 | 2009-08-20 | High frequency surfacewave radar |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0815398A GB0815398D0 (en) | 2008-08-20 | 2008-08-20 | High frequency surfacewave radar |
EP08252791A EP2157443A1 (en) | 2008-08-20 | 2008-08-20 | High frequency surfacewave radar |
EP09807959A EP2329290A1 (en) | 2008-08-20 | 2009-08-20 | High frequency surfacewave radar |
PCT/GB2009/051038 WO2010020813A1 (en) | 2008-08-20 | 2009-08-20 | High frequency surfacewave radar |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2329290A1 true EP2329290A1 (en) | 2011-06-08 |
Family
ID=41136909
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP09807959A Withdrawn EP2329290A1 (en) | 2008-08-20 | 2009-08-20 | High frequency surfacewave radar |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2329290A1 (en) |
AU (1) | AU2009283967A1 (en) |
WO (1) | WO2010020813A1 (en) |
Families Citing this family (63)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2500052A (en) | 2012-03-08 | 2013-09-11 | Univ Antwerpen | Target detection |
US9910144B2 (en) | 2013-03-07 | 2018-03-06 | Cpg Technologies, Llc | Excitation and use of guided surface wave modes on lossy media |
US9912031B2 (en) | 2013-03-07 | 2018-03-06 | Cpg Technologies, Llc | Excitation and use of guided surface wave modes on lossy media |
US9941566B2 (en) | 2014-09-10 | 2018-04-10 | Cpg Technologies, Llc | Excitation and use of guided surface wave modes on lossy media |
US10498393B2 (en) | 2014-09-11 | 2019-12-03 | Cpg Technologies, Llc | Guided surface wave powered sensing devices |
US10079573B2 (en) | 2014-09-11 | 2018-09-18 | Cpg Technologies, Llc | Embedding data on a power signal |
US10101444B2 (en) | 2014-09-11 | 2018-10-16 | Cpg Technologies, Llc | Remote surface sensing using guided surface wave modes on lossy media |
US9960470B2 (en) | 2014-09-11 | 2018-05-01 | Cpg Technologies, Llc | Site preparation for guided surface wave transmission in a lossy media |
US10001553B2 (en) | 2014-09-11 | 2018-06-19 | Cpg Technologies, Llc | Geolocation with guided surface waves |
US9887587B2 (en) | 2014-09-11 | 2018-02-06 | Cpg Technologies, Llc | Variable frequency receivers for guided surface wave transmissions |
US9887557B2 (en) | 2014-09-11 | 2018-02-06 | Cpg Technologies, Llc | Hierarchical power distribution |
US10033198B2 (en) | 2014-09-11 | 2018-07-24 | Cpg Technologies, Llc | Frequency division multiplexing for wireless power providers |
US9882397B2 (en) | 2014-09-11 | 2018-01-30 | Cpg Technologies, Llc | Guided surface wave transmission of multiple frequencies in a lossy media |
US10175203B2 (en) | 2014-09-11 | 2019-01-08 | Cpg Technologies, Llc | Subsurface sensing using guided surface wave modes on lossy media |
US10084223B2 (en) | 2014-09-11 | 2018-09-25 | Cpg Technologies, Llc | Modulated guided surface waves |
US10074993B2 (en) | 2014-09-11 | 2018-09-11 | Cpg Technologies, Llc | Simultaneous transmission and reception of guided surface waves |
US9887556B2 (en) | 2014-09-11 | 2018-02-06 | Cpg Technologies, Llc | Chemically enhanced isolated capacitance |
US9893402B2 (en) * | 2014-09-11 | 2018-02-13 | Cpg Technologies, Llc | Superposition of guided surface waves on lossy media |
US9859707B2 (en) | 2014-09-11 | 2018-01-02 | Cpg Technologies, Llc | Simultaneous multifrequency receive circuits |
US10027116B2 (en) * | 2014-09-11 | 2018-07-17 | Cpg Technologies, Llc | Adaptation of polyphase waveguide probes |
US9923385B2 (en) | 2015-06-02 | 2018-03-20 | Cpg Technologies, Llc | Excitation and use of guided surface waves |
US10193595B2 (en) | 2015-06-02 | 2019-01-29 | Cpg Technologies, Llc | Excitation and use of guided surface waves |
US9921256B2 (en) | 2015-09-08 | 2018-03-20 | Cpg Technologies, Llc | Field strength monitoring for optimal performance |
US9887585B2 (en) | 2015-09-08 | 2018-02-06 | Cpg Technologies, Llc | Changing guided surface wave transmissions to follow load conditions |
US9997040B2 (en) | 2015-09-08 | 2018-06-12 | Cpg Technologies, Llc | Global emergency and disaster transmission |
US9857402B2 (en) | 2015-09-08 | 2018-01-02 | CPG Technologies, L.L.C. | Measuring and reporting power received from guided surface waves |
US10122218B2 (en) | 2015-09-08 | 2018-11-06 | Cpg Technologies, Llc | Long distance transmission of offshore power |
US9496921B1 (en) | 2015-09-09 | 2016-11-15 | Cpg Technologies | Hybrid guided surface wave communication |
US10033197B2 (en) | 2015-09-09 | 2018-07-24 | Cpg Technologies, Llc | Object identification system and method |
US10062944B2 (en) | 2015-09-09 | 2018-08-28 | CPG Technologies, Inc. | Guided surface waveguide probes |
US9916485B1 (en) | 2015-09-09 | 2018-03-13 | Cpg Technologies, Llc | Method of managing objects using an electromagnetic guided surface waves over a terrestrial medium |
US9885742B2 (en) | 2015-09-09 | 2018-02-06 | Cpg Technologies, Llc | Detecting unauthorized consumption of electrical energy |
US10205326B2 (en) | 2015-09-09 | 2019-02-12 | Cpg Technologies, Llc | Adaptation of energy consumption node for guided surface wave reception |
JP2018534897A (en) | 2015-09-09 | 2018-11-22 | シーピージー テクノロジーズ、 エルエルシーCpg Technologies, Llc | Load limiting in inductive surface wave power supply systems. |
US9882436B2 (en) | 2015-09-09 | 2018-01-30 | Cpg Technologies, Llc | Return coupled wireless power transmission |
CN108352725A (en) | 2015-09-09 | 2018-07-31 | Cpg技术有限责任公司 | Guide surface waveguide photodetector |
US10027131B2 (en) | 2015-09-09 | 2018-07-17 | CPG Technologies, Inc. | Classification of transmission |
US10063095B2 (en) | 2015-09-09 | 2018-08-28 | CPG Technologies, Inc. | Deterring theft in wireless power systems |
US10031208B2 (en) | 2015-09-09 | 2018-07-24 | Cpg Technologies, Llc | Object identification system and method |
US9927477B1 (en) | 2015-09-09 | 2018-03-27 | Cpg Technologies, Llc | Object identification system and method |
US9973037B1 (en) | 2015-09-09 | 2018-05-15 | Cpg Technologies, Llc | Object identification system and method |
US9887558B2 (en) | 2015-09-09 | 2018-02-06 | Cpg Technologies, Llc | Wired and wireless power distribution coexistence |
WO2017044269A1 (en) | 2015-09-09 | 2017-03-16 | Cpg Technologies, Llc. | Power internal medical devices with guided surface waves |
US10396566B2 (en) | 2015-09-10 | 2019-08-27 | Cpg Technologies, Llc | Geolocation using guided surface waves |
US10408916B2 (en) | 2015-09-10 | 2019-09-10 | Cpg Technologies, Llc | Geolocation using guided surface waves |
BR112018004919A2 (en) | 2015-09-10 | 2019-05-14 | Cpg Technologies, Llc | apparatus and method |
US10103452B2 (en) | 2015-09-10 | 2018-10-16 | Cpg Technologies, Llc | Hybrid phased array transmission |
US10498006B2 (en) | 2015-09-10 | 2019-12-03 | Cpg Technologies, Llc | Guided surface wave transmissions that illuminate defined regions |
EP3341748A2 (en) | 2015-09-10 | 2018-07-04 | CPG Technologies, LLC | Geolocation using guided surface waves |
US10559893B1 (en) | 2015-09-10 | 2020-02-11 | Cpg Technologies, Llc | Pulse protection circuits to deter theft |
US10193229B2 (en) | 2015-09-10 | 2019-01-29 | Cpg Technologies, Llc | Magnetic coils having cores with high magnetic permeability |
US10408915B2 (en) | 2015-09-10 | 2019-09-10 | Cpg Technologies, Llc | Geolocation using guided surface waves |
EA201890689A1 (en) | 2015-09-10 | 2018-10-31 | Сипиджи Текнолоджиз, Элэлси. | MOBILE PROBES OF DIRECTED SURFACE WAVEGUIDE AND RECEIVERS |
US10324163B2 (en) | 2015-09-10 | 2019-06-18 | Cpg Technologies, Llc | Geolocation using guided surface waves |
US10312747B2 (en) | 2015-09-10 | 2019-06-04 | Cpg Technologies, Llc | Authentication to enable/disable guided surface wave receive equipment |
KR20180051604A (en) | 2015-09-11 | 2018-05-16 | 씨피지 테크놀로지스, 엘엘씨. | Enhanced guided surface waveguide probes |
EA201890711A1 (en) | 2015-09-11 | 2018-09-28 | Сипиджи Текнолоджиз, Элэлси. | GLOBAL MULTIPLICATION OF ELECTRICAL POWER |
US10559866B2 (en) | 2017-03-07 | 2020-02-11 | Cpg Technologies, Inc | Measuring operational parameters at the guided surface waveguide probe |
US10559867B2 (en) | 2017-03-07 | 2020-02-11 | Cpg Technologies, Llc | Minimizing atmospheric discharge within a guided surface waveguide probe |
US10630111B2 (en) | 2017-03-07 | 2020-04-21 | Cpg Technologies, Llc | Adjustment of guided surface waveguide probe operation |
US10581492B1 (en) | 2017-03-07 | 2020-03-03 | Cpg Technologies, Llc | Heat management around a phase delay coil in a probe |
US20200190192A1 (en) | 2017-03-07 | 2020-06-18 | Sutro Biopharma, Inc. | Pd-1/tim-3 bi-specific antibodies, compositions thereof, and methods of making and using the same |
US10560147B1 (en) | 2017-03-07 | 2020-02-11 | Cpg Technologies, Llc | Guided surface waveguide probe control system |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2825900A (en) * | 1950-02-17 | 1958-03-04 | Rand Corp | Directional receiver |
GB8429724D0 (en) * | 1984-11-24 | 2001-11-28 | Gen Electric Co Plc | A wide bandwidth radar |
US5293176A (en) * | 1991-11-18 | 1994-03-08 | Apti, Inc. | Folded cross grid dipole antenna element |
US5418544A (en) * | 1993-04-16 | 1995-05-23 | Apti, Inc. | Stacked crossed grid dipole antenna array element |
GB2387053B (en) * | 2001-11-12 | 2006-02-01 | Telstra Corp Ltd | Surface wave radar |
US6762730B2 (en) * | 2002-10-04 | 2004-07-13 | Spx Corporation | Crossed bow tie slot antenna |
-
2009
- 2009-08-20 WO PCT/GB2009/051038 patent/WO2010020813A1/en active Application Filing
- 2009-08-20 AU AU2009283967A patent/AU2009283967A1/en not_active Abandoned
- 2009-08-20 EP EP09807959A patent/EP2329290A1/en not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
See references of WO2010020813A1 * |
Also Published As
Publication number | Publication date |
---|---|
AU2009283967A1 (en) | 2010-02-25 |
WO2010020813A8 (en) | 2011-05-05 |
WO2010020813A1 (en) | 2010-02-25 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2010020813A1 (en) | High frequency surfacewave radar | |
EP2556385B1 (en) | Electronic counter measure system | |
US7737879B2 (en) | Split aperture array for increased short range target coverage | |
KR100871432B1 (en) | Low altitude radar antenna | |
JP3393204B2 (en) | Multi-beam radar device | |
US20130088393A1 (en) | Transmit and receive phased array for automotive radar improvement | |
CN111352081B (en) | Traveling wave imaging manifold for high resolution radar system | |
CN107290728B (en) | Equivalent electromagnetic wave orbital angular momentum pulse radar detection method and system | |
JP4371124B2 (en) | Antenna device | |
JP7098732B2 (en) | Radar system | |
CN201673998U (en) | Traveling-wave type multi-beam circular polarized antenna | |
EP2157443A1 (en) | High frequency surfacewave radar | |
KR101007213B1 (en) | Antenna combiner of radar system where many radiation patterns can be synthesized | |
Moore | UK airborne AESA radar research | |
EP3780274A1 (en) | An array antenna arrangement | |
CN217215090U (en) | Radar antenna, radar and electromechanical device | |
Adrian | From AESA radar to digital radar for surface-based applications | |
WO1986007467A1 (en) | Multibeam surveillance radar | |
RU2794466C1 (en) | Method for surveying airspace by a pulse-doppler radar station with an active phased antenna array | |
Adrian | From AESA radar to digital radar for surface applications | |
Kjellén | Realisation study of digital radar array (DRA) | |
Saleem et al. | STUDY OF PHASED ARRAY ANTENNA AND RADAR TECHNOLOGY | |
WO2019138037A1 (en) | Radar systems | |
CN117595906A (en) | Active wave beam shaping network | |
Alam et al. | RF interference suppression in transmitting stations |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20110218 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK SM TR |
|
AX | Request for extension of the european patent |
Extension state: AL BA RS |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20110510 |