GB2048600A - Anti-collision vehicle radar system - Google Patents
Anti-collision vehicle radar system Download PDFInfo
- Publication number
- GB2048600A GB2048600A GB7913451A GB7913451A GB2048600A GB 2048600 A GB2048600 A GB 2048600A GB 7913451 A GB7913451 A GB 7913451A GB 7913451 A GB7913451 A GB 7913451A GB 2048600 A GB2048600 A GB 2048600A
- Authority
- GB
- United Kingdom
- Prior art keywords
- radar
- receiving
- coiled
- transmitting
- polarization
- 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- Withdrawn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
- 230000010287 polarization Effects 0.000 claims abstract description 42
- 230000002452 interceptive effect Effects 0.000 claims abstract description 14
- 230000002238 attenuated effect Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000523 sample Substances 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
- G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
- G01S13/76—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems wherein pulse-type signals are transmitted
- G01S13/78—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems wherein pulse-type signals are transmitted discriminating between different kinds of targets, e.g. IFF-radar, i.e. identification of friend or foe
-
- 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
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
-
- 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
- G01S7/024—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using polarisation effects
- G01S7/026—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using polarisation effects involving the transmission of elliptically or circularly polarised waves
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
An anti-collision vehicle radar system (12) overcomes interference from radar systems on other vehicles by providing a radar transmitter (15) having a transmitting antenna (14) which transmits a radar beam having circular polarization with a particular direction of rotation of the polarization, a radar receiver (18) for receiving the reflected radar beam and including a receiving antenna (16) which discriminates in favour or received signals having circular polarization with the particular direction of rotation but which discriminates against received signals having circular polarization with the opposite direction of rotation. The receiving antenna is thus effective to discriminate in favour of a reflected radar beam from the associated transmitting antenna while discriminating against an interfering radar beam. Utilization devices (22) are connected to the receiver for utilizing received radar signals to control operation of the vehicle (10). <IMAGE>
Description
SPECIFICATION
Anti-collision vehicle radar system
This invention relates to an anti-collision vehicle radar system, adapted to control the operation of a vehicle, so as to avoid collisions with other vehicles and with obstacles of all kinds.
The radar system is applicable to vehicles generally, including passenger automobiles, trucks, buses, rapid transit trains, and all other types of railroad trains, for example.
Many such anti-collision vehicle radar systems have been proposed in the prior art. Typically, such an anti-collision radar system includes a radar transmitter, a transmitting antenna mounted on the vehicle for transmitting a radar receiver for receiving the reflected radar beam, after it has been reflected by another vehicle or any other obstacle. The radar system may include means for measuring the range or distance between the vehicle and the obstacle, and also the rate or velocity with which the vehicle is approaching the obstacle. The radar system may include means for automatically actuating the brakes of the vehicle, if the range and velocity information indicatesth t it is necessary to stop or slow down the vehicle to avoid a collision with the obstacle.
Prior anti-collision vehicle radar systems have been afflicted with the problem of interference from radar beams transmitted by similar radar systems on other vehicles. An anti-collision radar system is not of much value unless radar units can be installed on all vehicles, without causing interference problems between the radar units on approaching vehicles.
With prior radar systems, the radar units on approaching vehicles have severely interfered with each other, in that each radar receiver has been blinded or overloaded by the strong radar beam from the approaching vehicle, to such an extent that each radar receiver has been rendered incapable of effectively receiving the weaker reflected beam from its own transmitter.
The principal object of the present invention is to provide a new and improved anti-collision vehicle radar system which is capable of discriminating in favor of the reflected radar beam, while discriminating against any radar beam from a similar radar system on another vehicle, so that the radar system can effectively receive and analyze the reflected beam, without being blinded by any radar beam from another vehicle.
In accordance with the present invention, this objective is achieved by providing radar transmitting means for transmitting a radar beam having circular polarization with a particular direction of rotation of the polarization, radar receiving means for receiving the beam after reflection thereof and including means for discriminating in favor of received signals having circular polarization with such particular direction of rotation, while discriminating against received signals having circular polarization with the opposite direction of rotation of the polarization, and utilization means connected to the receiving means for utilizing received radar signals to control the operation of the vehicle. In this way, the receiving means is effective to discriminate in favor of the reflected radar beam while discriminating against any interfering radar beam from another vehicle radar system.The transmitted radar beam, with its circular polarization, is reflected from obstacles without anh change in the direction of rotation of the polarization. However, the circularly polarized beam from an approaching vehicle is received with the opposite direction of rotation ofthe polarization, due to the fact that the orientation of the approaching vehicle is reversed relative to the orientation of the base vehicle.
To produce the circularly polarized radar beam, the radar transmitter may employ transmitting antenna means having a coiled antenna element
The receiving antenna means may employ an antenna element which is coiled in the opposite direction, to discriminate against any interfering radar beam. The transmitting and receiving antenna elements are preferably helical in shape, with opposite coiling directions. The helical antenna elements have the additional advantage of being highly directional, so as to produce a narrow beam width.
Further objects, advantages and features of the present invention will appear from the following description, taken with the accompanying drawings, in which:
Fig. 1 is a diagrammatic plan view showing twn approaching vehicles equipped with anti-coll-- r radar systems to be described as illustrative embodiments of the present invention.
Fig. 2 is a diagrammatic sectional view showing a helical radar antenna which may be employed in the radar system.
Fig. 3 is a more detailed sectional view showing a similar helical antenna, but with an opposite coiling direction.
Fig. 4 is a front view of the helical antenna of Fig. 3.
Fig. 1 illustrates two identical vehicles 10 having identical radar systems 12, to be described as illustrative embodiments of the present invention. Each radar system 12 comprises radar transmitting' means including a helical transmitting antenna 14 connected to a radar transmitter 15. Each radar system 12 also comprises receiving means including a helical receiving antenna 16 connected to a radar receiver 18, the output of which is connected to a signal processor 20, adapted to operate utilization devices 22 for controlling the operation of the vehicle. The transmitter 15, receiver 18, signal processor 20 and the utilization devices 22 may employ the technology of the prior art, or any other suitable technology.
As shown, the helical transmitting and receiving antennas 14 and 16 comprise helical coils 24T and 24R, which are mounted in front of metal plates 26 serving as reflectors. The transmitting antenna 14 of each radar system 12 radiates a circularly polarized radar beam in which the polarization rotates in a particular direction which may be either clockwise or counterclockwise, but is the same for all of the radar systems on all vehicles. This radar beam is reflected by any obstruction and is returned with the same
absolute direction of rotation of the polarization. The
receiving antenna 16 is constructed so as to dis
criminate in favor of this direction of rotation.
If two vehicles are approaching each other while travelling in opposite directions, as illustrated in Fig.
1, each radar system will receive any interfering
radar beam from the system on the other vehicle, in
addition to its own reflected beam. The interfering
beam has a circular polarization which is rotating in the opposite direction, because the interfering beam
is being viewed from the receiving end of the beam
rather than from the transmitting end. Thus, if each radar system is transmitting a radar beam with clockwise polarization, the interfering beam from another vehicle headed or oriented in the opposite direction is received with a counterclockwise polarization, while its own reflected beam is received with a clockwise polarization. The receiving antenna 16 of each radar system is then constructed so as to discriminate against the counter-clockwise polarization of the interfering beam, while discriminating in favor of the clockwise polarization of the reflected beam.
In this way, the interfering beam can be rejected or attenuated by as much as 40 D.B., relative to the reflected beam, so that each radar system will be able to distinguish between the reflected beam and the interfering beam. Thus, each radar system is able to receive, analyze and measure its own reflected beam, without being blinded, overloaded or confused by an interfering beam.
To achieve the desired discrimination, the helical
receiving antenna element 24R should be coiled in the opposite direction, relative to the coiling direction of the transmitting antenna element 24T. The opposite coiling directions are illustrated in Fig. 1.
Except for the opposite coiling directions, the trans
mitting and receiving antennas 14 and 16 may be
basically the same.
Additional details of the transmitting and receiving antennas 14 and 16 are shown in Figs. 2,3 and 4. Fig.
2 is diagrammatic, while Fig. 3 is more detailed. It may be considered that Fig. 2 illustrates the receiving antenna 16, while Figs. 3 and 4 illustrate the transmitting antenna 14. It will be noted that the opposite coiling directions are employed for the helical receiving antenna element 24R and the helical transmitting antenna element 24T. In each case, the axis of the coil 24R and 24T coincides with the desired direction of propagation. The conductive reflector plate 26 is perpendicular to the axis of the helical coil 24T or 24R.
In each case, the antenna coil 24T or R is fed by forming one end of the coil into an axial lead 30 which may be coupled to a coaxial line or a wave guide. As shown in Fig. 3, the lead 30 extends axially through a cylindrical bore 32 in a cylindrical conductor 34, into a wave guide 36. Within the wave guide 36, the end of the lead 30 serves as a probe 38, ter
minating in a ball 40 which is for the purpose of
broad band matching. The wave guide 36 may be employed to supply energy to or from the antenna
14 or 16. The illustrated wave guide 36 has a tuning stub 42 in which a conductive tuning slug 44 is slidable. Any known or suitable wave guide or other feed technology may be employed. The antenna element 24T or R may be tuned by adjusting the
length or position of the lead 30.
The helical transmitting and receiving antennas 14 and 16 have the additional advantage of being highly directional, so as to provide a narrow beam width. In this way, interference is reduced and the strength of the reflected beam is increased.
The helical transmitting antenna 14 radiates electromagnetic radio waves having circular polarization. Other types of antennas may be employed to radiate waves having circular polarization. For example, other types of coiled antenna elements may be employed, such as spiral coils.
In a circularly polarized wave, the transverse polarization of the wave rotates. In the case of the helical transmitting antenna 14, the direction of rotation depends upon the coiling direction of the helical coil.
A circularly polarized wave may be regarded as comprising two wave components which are 90c out of phase electrically and are polarized along transverse planes which are 90" apart, such as horizontal and vertical planes. The two wave components combine to form a wave which is circular or rotary.
The rotation ofthe polarization may be in either direction about the axis of propagation ofthewave.
The radar system of the present invention may be operated at various radio frequencies, but it is particularly advantageous to operate the radar system at extreme ultra-high frequencies, such as the so called X band at about 10 gigahertz. In this band, a high degree of directionality can be achieved with small antennas. Thus, the helical transmitting and receiving antennas 14 and 16 will achieve an extremely narrow beam width.
Any known or suitable radar technology may be employed to analyze and measure the reflected radar signals. Thus, technology is available to measure the range or distance between the vehicle and the obstruction, and also the relative speed or velocity between the vehicle and the obstacle. The radar system may be programmed to operate the brakes of the vehicle automatically, if the range and velocity information indicate that there is danger of a collision between the vehicle and the obstacle. Other controls of the vehicle can also be operated, if desired.
With the radar system of the present invention, every automobile and every other automotive vehicle can be equipped with a radar set to prevent any vehicle from colliding with another vehicle or any other obstacle. The radar sets on approaching vehicles will not interfere with one another, because each radar set is able to discriminate in favor of its own reflected beam. while discriminating against the beam from an oncoming vehicle. This discrimination results from the circular polarization of the transmitted radar beams, plus the ability of the receiving antennas to discriminate in favorofcircu- lar polarization in one direction of rotation, while discriminating against circular polarization in the opposite direction of rotation.
Claims (9)
1. An anti-collision vehicle radar system, comprising radartransmitting means including atransmitting antenna including transmitting antenna means for transmitting a radar beam having circular polarization with a particular direction of rotation of the polarization, radar receiving meons for receiving said beam after reflection thereof and including a receiving antenna including receiving antenna means for discriminating in favor of received signals having circular polarization with said particular direction of rotation while discriminating against received signals having circular polarization with the opposite direction of rotation of the polarization, said system thereby being effective to discriminate in favor of a reflected radar beam from said transmitting means while discriminating against any interfering radar beam received directly from another similar vehicle radar system, and utilization means connected to said receiving means for utilizing received radar signals to control the operation of a vehicle.
2. An anti-collision vehicle radar system according to claim 1, in which said transmitting antenna means includes a helical transmitting antenna element which is coiled in one direction, said receiving antenna means including a helical receiving antenna element which is coiled in the opposite direction.
3. An anti-collision vehicle radar system according to claim 1, in which said transmitting antenna means includes an antenna element coiled in one direction, said receiving antenna means including an antenna element coiled in the opposite direction.
4. An anti-collision vehicle radar system, comprising transmitting means fortransmitting a radar beam having circular polarization with a particular direction of rotation of the polarization, radar receiving means for receiving the radar beam after reflection thereof and including means for discriminating in favor of received signals having circular polarization with said particular direction of rotation while discriminating against received signals having circular polarization with the opposite direction of rotation of the polarization, said system thereby being effective to discriminate in favor of a reflected radar beam from said transmitting means while discriminating against any interfering radar beam received directly from another similar vehicle radar system, and utilization means connected to said receiving means for utilizing received radar signals to control the operation of a vehicle.
5. An anti-collison vehicle radar system according to claim 4, in which said transmitting means includes a helically coiled transmitting antenna element coiled in one direction, said receiving means including a helically coiled receiving antenna element coiled in the opposite direction.
6. An anti-collision vehicle radar system according to claim 4, in which said transmitting means includes a coiled transmitting antenna element coiled in one direction, said receiving means including a coiled receiving antenna element coiled in the opposite direction.
7. An anti-collision vehicle radar system, comprising radartransmitting means including transmit- ting antenna means for transmitting a radar beam having circular polarization with a particular direction of rotation of the polarization, and radar receiving means for receiving said beam after reflection thereof and including receiving antenna means for
discriminating in favor of received signals having
circular polarization with said particular direction of
rotation while discriminating against received sign
als having circular polarization with the opposite
direction of rotation of the polarization, said system
thereby being effective to discriminate in favor of a
reflected radar beam from said transmitting means
while discriminating against any interfering radar
beam received directly from another similar vehicle
radar system.
8. An anti-collision vehicle radar system accord
ing to claim 7, in which said transmitting antenna
means includes a helical transmitting antenna element which is coiled in one direction, said receiving
antenna means including a helical receiving antenna
element which is coiled in the opposite direction.
9. An anti-collision vehicle radar system accord
ing to claim 7, in which said transmitting antenna
means includes an antenna element coiled in one
direction, said receiving antenna means including an
antenna element coiled in the opposite direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7913451A GB2048600A (en) | 1979-04-18 | 1979-04-18 | Anti-collision vehicle radar system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7913451A GB2048600A (en) | 1979-04-18 | 1979-04-18 | Anti-collision vehicle radar system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2048600A true GB2048600A (en) | 1980-12-10 |
Family
ID=10504616
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7913451A Withdrawn GB2048600A (en) | 1979-04-18 | 1979-04-18 | Anti-collision vehicle radar system |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2048600A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2621134A1 (en) * | 1987-09-26 | 1989-03-31 | Matsushita Electric Works Ltd | MOBILE OBJECT DISCRIMINATION SYSTEM |
| EP0247612A3 (en) * | 1986-05-30 | 1989-12-13 | Sharp Kabushiki Kaisha | Microwave data transmission apparatus |
| EP0308964A3 (en) * | 1987-09-24 | 1990-10-10 | Fujitsu Limited | Radio-frequency identification system |
| WO1990010200A3 (en) * | 1989-02-27 | 1990-11-29 | Hyper X Sa | Identification system using hertzian waves, consisting of an interrogation station and a responder unit |
| GB2299722A (en) * | 1995-04-04 | 1996-10-09 | Gunars Berzins | Improvement to radars and sonars |
| EP0803070A4 (en) * | 1995-01-09 | 1998-04-15 | Northrop Grumman Corp | Radar signal selection based upon antenna bearing |
| GB2351196A (en) * | 1999-04-01 | 2000-12-20 | Lear Automotive Dearborn Inc | Polarametric blind spot detector with steerable beam |
-
1979
- 1979-04-18 GB GB7913451A patent/GB2048600A/en not_active Withdrawn
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0247612A3 (en) * | 1986-05-30 | 1989-12-13 | Sharp Kabushiki Kaisha | Microwave data transmission apparatus |
| US4926182A (en) * | 1986-05-30 | 1990-05-15 | Sharp Kabushiki Kaisha | Microwave data transmission apparatus |
| EP0308964A3 (en) * | 1987-09-24 | 1990-10-10 | Fujitsu Limited | Radio-frequency identification system |
| FR2621134A1 (en) * | 1987-09-26 | 1989-03-31 | Matsushita Electric Works Ltd | MOBILE OBJECT DISCRIMINATION SYSTEM |
| WO1990010200A3 (en) * | 1989-02-27 | 1990-11-29 | Hyper X Sa | Identification system using hertzian waves, consisting of an interrogation station and a responder unit |
| AU629921B2 (en) * | 1989-02-27 | 1992-10-15 | Thomson-Csf | Identification system using hertzian waves, consisting of an interrogation station and a responder unit |
| US5258762A (en) * | 1989-02-27 | 1993-11-02 | Philippe Cabon | Identification system using hertzian waves, consisting of an interrogation station and a responder unit |
| EP0803070A4 (en) * | 1995-01-09 | 1998-04-15 | Northrop Grumman Corp | Radar signal selection based upon antenna bearing |
| GB2299722A (en) * | 1995-04-04 | 1996-10-09 | Gunars Berzins | Improvement to radars and sonars |
| GB2351196A (en) * | 1999-04-01 | 2000-12-20 | Lear Automotive Dearborn Inc | Polarametric blind spot detector with steerable beam |
| GB2351196B (en) * | 1999-04-01 | 2004-03-03 | Lear Automotive Dearborn Inc | Polarametric blind spot detector with steerable beam |
| US6734807B2 (en) | 1999-04-01 | 2004-05-11 | Lear Automotive Dearborn, Inc. | Polarametric blind spot detector with steerable beam |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |