GB2298540A - Inter-vehicle proximity warning device - Google Patents
Inter-vehicle proximity warning device Download PDFInfo
- Publication number
- GB2298540A GB2298540A GB9503982A GB9503982A GB2298540A GB 2298540 A GB2298540 A GB 2298540A GB 9503982 A GB9503982 A GB 9503982A GB 9503982 A GB9503982 A GB 9503982A GB 2298540 A GB2298540 A GB 2298540A
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- United Kingdom
- Prior art keywords
- vehicle
- warning
- detecting means
- proximity
- inter
- Prior art date
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/14—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring differences of pressure in the fluid
-
- 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
- G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
-
- 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
- G01S13/886—Radar or analogous systems specially adapted for specific applications for alarm 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
- 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
- G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
- G01S2013/9316—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles combined with communication equipment with other vehicles or with base stations
-
- 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
- G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
- G01S2013/932—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles using own vehicle data, e.g. ground speed, steering wheel direction
-
- 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
- G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
- G01S2013/9322—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles using additional data, e.g. driver condition, road state or weather data
-
- 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
- G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
- G01S2013/9325—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles for inter-vehicle distance regulation, e.g. navigating in platoons
-
- 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
- G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
- G01S2013/9327—Sensor installation details
- G01S2013/93271—Sensor installation details in the front of the vehicles
-
- 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
- G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
- G01S2013/9327—Sensor installation details
- G01S2013/93272—Sensor installation details in the back of the vehicles
-
- 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
- G01S7/04—Display arrangements
- G01S7/06—Cathode-ray tube displays or other two dimensional or three-dimensional displays
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- General Physics & Mathematics (AREA)
- Aviation & Aerospace Engineering (AREA)
- Electromagnetism (AREA)
- Computer Networks & Wireless Communication (AREA)
- Emergency Alarm Devices (AREA)
Abstract
Inter-vehicle proximity warning device for providing a visible and/or audible warning when a vehicle is closer than a predetermined distance to another vehicle. The device includes a voltage regulator 1, a speed sensor 2, an amplifier 3, a vehicle turning sensor 4, a power stabiliser 5, a proximity detector 6 and a warning device 7 connected in series and in that order. The proximity detector 6 includes a Gunn oscillator beam projector and a mixer diode beam detecting means. The device is suitable for sensing the proximity of a following or a followed vehicle and the warning device 7, includes a high intensity brake light 7 or a dashboard mountable visual or audible warning means depending on whether the proximity sensor faces backwards or forwards. Actuation of the device can be arranged to occur automatically upon illumination of a vehicle's fog lamps and deactivation may occur when the vehicle is travelling below a predetermined speed or turning more than a predetermined amount. Ultrasonic or infra-red sensors may be used in alternative embodiments. The speed sensor 2 is a piezo-electric airflow (air pressure) sensor (fig 2).
Description
INTER-VEHICLE PROXIMITY WARNING DEVICE
This invention relates to a vehicle proximity warning device.
Statistics have indicated that a high proportion of motor vehicle accidents occur because drivers follow the vehicle ahead too closely both in good and reduced visibility driving conditions, at speeds of 13.4 m/s (30 mph) and above.
Devices are known which detect obstacles in the path of a reversing vehicle. Such a device provides an audible alarm as a warning that collision with the object is likely. However, because such devices function by means of a long wave ultrasonic beam, their detection range is limited to approximately two metres.
It is an objection of the invention to provide a device for warning the driver of a vehicle following too close behind another vehicle that he or she is at risk of rear end collision. A further object of the invention is to provide a device for warning the driver of a vehicle that he or she is following another vehicle too closely, such a device would be particularly useful when driving in conditions of reduced visibility.
The invention consists in an inter-vehicle proximity warning device for mounting in a vehicle, said device including beam projecting means, beam detecting means for detecting a reflection of the beam from an object located within a specified distance which is at least lOm from the beam detecting means, and warning means responsive to the beam detecting means to indicate the presence of such an object. Such a device can be installed in a vehicle, sense that there is an increased chance of collision with another vehicle and provide an appropriate warning. The device can be arranged to sense either a following or a followed vehicle.
Preferably, the specified distance is at least 20 metres from the detecting means so as to increase the detection range and thus provide an earlier warning. For a still greater detection range the specified distance may be at least 30 metres from the detecting device.
Preferably the device includes vehicle speed dependent means for varying the specified distance. Thus, the greater stopping distance which is required to avoid a collision when a vehicle travels at a higher speed, is taken into account.
The beam projecting means and beam detecting means preferably comprise a Gunn oscillator and a mixer diode respectively. These components are inexpensive and are not prone to interference. Alternatively, the beam projecting means and the beam detecting means may comprise an ultrasonic transducer, or an infrared emitting diode and a filter detecting diode or phototransistor.
The warning means preferably includes at least one visible warning unit. When the beam projecting means and beam detecting means are mounted so as to detect a following vehicle, the warning means may include a red light for warning a following vehicle. Means are preferably included for intermittently illuminating the red light in order to identify its warning function. The warning may alternatively be effected by means of the light being illuminated throughout a period in which an object is within the specified distance. The red light may also provide, as its primary function, a vehicle brake light.
with such an arrangement the device preferably includes means for overriding the intermittent illumination of the red light when the vehicle's foot brake is applied.
Advantageously, the device preferably includes vehicle turning sensing means, such as steering wheel rotation sensing means for deactivating the device when the sensing means detect that turning of the vehicle is occurring. The rotation sensing means detects when steering wheel rotation of more than a predetermined angle, for example 150, occurs. In this way, false triggering of the device, resulting from roadside obstacles when the vehicle turns is reduced.
Means are preferably provided for deactivating the device when the vehicle is travelling at less than a predetermined speed. In this way false triggering of the device at lower speeds, for example in congested traffic conditions when vehicles may follow each other closely, can be avoided.
The warning means may include a dashboard mountable light and may also include an audible warning unit. Such warning means are preferable when the beam projecting means and the beam detecting means are arranged to detect an obstacle in the vehicle's path, in conditions of reduced visibility. For this purpose, means may be provided for activating the device in response to the activation of the vehicle's fog lights in order that the device will be automatically actuated in conditions in which it is necessary.
Preferably the beam projecting means and the beam detecting means are configured to operate using X-band or
Cx-band frequencies of between 5.2 and 10.9 GHz. More preferably operation is at above 10 GHz so as to reduce the chance of interference by extraneous means such as halogen and sodium lamps and rain.
Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:
FIG. 1 is a block circuit diagram of a warning device according to one embodiment of the invention;
FIG. 2 is a circuit diagram of a voltage regulator of the device shown in Fig. 1;
FIG. 3 is a circuit diagram of a speed sensor of the device shown in Fig. 1;
FIG. 4 is a schematic diagram of an angular displacement switch of the device shown in Fig. 1;
FIG. 5 is a circuit diagram of a power stabiliser of the device shown in Fig. 1;
FIGS. 6A, 6B and 6C together form a circuit diagram of a proximity detector of the device shown in Fig. 1;
FIG. 6D is a circuit diagram of a warning lamp oscillator circuit for use in the invention;
FIG. 7 is a block circuit diagram of a vehicle proximity warning device according to a second embodiment of the invention;;
FIG. 8 is a circuit diagram of an alternative proximity detector; and
FIG. 9 is a circuit diagram of another alternative proximity detector.
Reference will firstly be made to Fig. 1 which schematically shows the integers of the rear warning device.
A voltage regulator 1, which provides electrical power for the device, is connected to a speed sensor 2, the output of which is connected via an amplifier 3 to an angular displacement switch 4. The output from the switch 4 is connected via a power stabiliser 5 to a proximity detector 6, which is in turn connected to a high-intensity brake light 7. The latter may be mounted on the rear parcel shelf or inside the rear window of the vehicle.
Fig. 2 shows the voltage regulator 1 which supplies electrical power to the warning device. A voltage regulator integrated circuit 8, of type LM2575, manufactured by National Semiconductor has its input 9 connected to the unregulated vehicle fused supply source of 12V to 14V. The active low control of the LM2575 is isolated by grounding the active pin 10 which means that the device switches on and off with the vehicle ignition.
The voltage regulator gives an output at 11 of 5V +/- 0.8V and 1.OA. The output is connected to ground via a reverse-biased zener diode D1 of type 1N4148 or 1N5822 and is fed through an inductor L1 of 330 pH. The voltage regulator 1 will be employed whether the device is arranged to sense a following or a followed vehicle and could permit the device to be used with an alternating current supply.
The output 11 of the voltage regulator 1 forms the input of the speed sensor 2 as shown in Fig. 3, which is used to switch the warning device on at vehicle speeds above 9.0 m/s (20 mph). The speed sensor includes a
Motorola MPXl00AP piezoresistive sensor 13 which is connected as feedback to a variable resistor 12 of 400Q to 550Q. The piezoresistive sensor is fitted to the front of the vehicle in order to measure the change of air pressure occurring as a result of the vehicle's motion. It is known that the air resistance on the vehicle increases with the square of the vehicle's speed or
Air resistance = kv2a where k is a constant, v is the speed of the vehicle and a is its frontal area.It has been established that average values of k for different types of vehicle are as follows:
Commercial vehicle/bus k = 0.0024
Saloon car k = 0.0017
Sports car k = 0.0012
Racing car k = 0.0006
The warning device uses an average of the above values of k of 0.0015. The air pressure on the piezoresistive sensor 13 is proportional to the square of the velocity of the vehicle relative to the air, which is the vector sum of the road speed of the vehicle and the speed of the wind. The piezoresistive sensor has a builtin reference vacuum of OkPa and the speed sensor gives an accurate linear voltage output at 14 which increases by 0.6 mV/kPa in proportion to the applied pressure above ambient pressure (approximately 100 kPa).The piezoresistive sensor has a range of O to 1550 kPa, a response time of 1 ms and a temperature coefficient of 0.19%/ C.
The output 14 of the speed sensor 2 is applied to the input of the amplifier 3, which consists of a duplicate of the operational amplifier 15 of type A74lC, shown in
Fig. 6B, with its associated input and feedback components
R8 to R10, C5 and C6, and which is supplied with power also as shown in Fig. 6B.
Fig. 4 shows the angular displacement switch 4, the input 16 of which is taken from the output of the amplifier 3. The angular displacement switch comprises a plastic encapsulated reed switch 17 and a plastic encapsulated moving electromagnet 18. The latter is positioned by means of dual sided adhesive fixers to the underside of the hub of the vehicle's steering wheel. The reed switch 17 is fixed in a similar way to the steering column such that when the steering wheel is in the "straight ahead" position the reed switch is closed, connecting the input 16 to the output 19, and ensuring that the warning device operates only when the vehicle is travelling in a substantially straight line.
The angular displacement switch 4 is configured such that rotation of the steering wheel beyond 20C to the left or right momentarily opens the reed switch, thus switching the warning device off. This reduces false triggering of the device which would otherwise occur when the vehicle performed manoeuvres such as turning through an acute bend or overtaking as a result of a roadside obstacle such as hedges or fences, or passing vehicles, entering the protected safety envelope.
The reed switch 17 has rhodium-plated single pole contacts which have a capacitance of 0.8 > F and a resistance of 80MQ. The operation time of the reed switch is 4ms and the release time 0.2ms, the operational life being 100 million operations. The output of the angular displacement switch 4 forms the input of the power stabiliser 5, as shown in Figure 5, which provides the required stable supply voltage to the proximity detector 6 despite fluctuations in the vehicle voltage which has been shown by experiment to vary between 10.8V and 13.8V. The input 19 supplies a power supply integrated circuit 20 of type L200CV. The output voltage occurring at 21 is set at 12V by an 820Q resistor 22 and a 210kQ variable resistor 23.The power stabiliser 5 limits the current and power supplied to the proximity detector 6, thus tending to prolong the life of the filament of the high-intensity brake light 7 and providing thermal shutdown and overvoltage protection. The power stabiliser 5 will be employed whether the device is arranged to sense a following or followed vehicle and could act as a power stabiliser enabling the device to be used with an alternating current.
Figure 6A shows the diode driver circuit of the proximity detector 6. The input 21 of this circuit is supplied from the 12V output of the power stabiliser 5.
This input is supplied via a resistor R1 to a "band gap" voltage reference integrated circuit 37 of type TL430C, the reference output of which is connected to the junction of two resistors R3, R4 having 1% tolerance. The input 21 is also applied to a transistor TR1 which drives an emitter follower transistor TR3 to supply currents of 160mA.
The voltage reference integrated circuit 37 and the resistors R3, R4 produce a stable input of 7V, + 100mV for a transceiver 38, which is fitted to the rear of the vehicle. The transceiver consists of two closely tuned cavities or waveguides and an antenna which gives a gain of about 5dB. One of the waveguides, the Gunn oscillator, contains a Gunn diode which emits a thin beam of X-band microwave energy at 10.687 GHZ. A diode of the 1N23 type is used, those with later prefixes (E, F, G) being preferred for their lower noise figures. The Gunn oscillator includes an iris which permits a variable detection range, however in this example the range is set by the power supply to the Gunn oscillator. The oscillator is made electrically an odd number of quarter wavelengths.
The other waveguide contains a mixer diode also of type 1N23, which acts as a receiver. There is a small hole between the two waveguides so that some of the transmitted signal passes directly to the receiver. The signal input end of the mixer waveguide is of any convenient length and is fitted with a matching screw to match the mixer diode to the wavelength. The mixer diode is biased to 38*A has a low impedance of 6004 and is decoupled at its hot end.
Signals reflected to the transceiver 23 from the environment are of exactly the same frequency of the transmitted signal. However, signals reflected from a moving object within the 15m (50') detection range of the transceiver are of a frequency which is changed slightly by the Doppler effect. For example, a difference in speed between the vehicle and the detected object of only one metre per second produces a frequent change of about 60Hz.
This slightly changed signal interferes with the transmitted signal in the mixer waveguide and produces a beat signal with a frequency equal to the change. All moving objects within range which have a frontal area greater than 0.25m2, are detected in this manner.
The low frequency beat signal is output from the mixer diode at terminal 24 of the transceiver 38, and applied to a transistor TR4 which is connected as a common base amplifier with bias current supplied by resistor R5.
The output from transistor TR4 is ac coupled via point B to the integrated circuit 15 of type WA741C as shown in Figure 6B. This integrated circuit is a non-inverting operational amplifier with a feedback capacitor C5 which ensures that only low frequency signals are amplified.
The output from the amplifier is applied to a lowpass filter 25, which is one half of an integrated circuit of type LF353. The cut off frequency of the low-pass filter is approximately 40Hz and signals of higher frequency are rejected. Thus the amplifier and the low pass filter 25 together prevent false triggering of the warning device by extraneous signal.
The output from the low-pass filter 25 is in turn applied to a variable gain amplifier 26 constituted by the other half of the LF353 circuit. The gain of this amplifier is preset by means of a variable resistor RV1 in order to adjust the sensitivity of the receiver.
Referring now to figure 6C, the amplified signal from the amplifier 25 is applied at point D via a capacitor C11 to diodes Dl, D2 and a capacitor C12. These four components remove the a.c. component from the audio signal and provide a d.c. bias to switch transistor TR2 and light emitting diode 27, the latter of which is used to test the warning device after installation.
The amplified signal from the amplifier 25 is applied at point D via a capacitor Cll to diodes D11, D12 and a capacitor C12. These four components remove the a.c.
component from the audio signal and provide a d.c. bias to switch transistor TR2 and light emitting diode 27, the latter of which is used to test the warning device after installation.
A 12V, 16A miniature pcb-mounted relay 28 is connected as shown. When the contacts of the relay are closed a current of 0.57A at 12V illuminates the highintensity brake light 7. When the contacts open, the brake light 7 is extinguished.
With the warning device as described above, if a moving object is detected within 15m (50') of the vehicle, the high-intensity brake light 7 flashes three times every second for each ten seconds that the safety zone is invaded, thus warning the driver of an approaching vehicle that he is too close. When the safety zone is clear, a safe breaking distance has been regained and the highintensity brake light is extinguished.
Figure 6D shows a typical warning lamp oscillator circuit for providing intermittent illumination of the high intensity brake light 7. An IC7555 timing circuit 60 provides alternate switching between its output pins 61 and 63. The flash frequency is given by the formula:
1.44
F =
(R63 + 2R62)C61 and the time tl between flashes is given by the formula: tl = 0.693 (R63 + R62 C1)
The values of the components are as follows:
R1 = 470Q R2 = 68kQ R3 = 4.7kin D21 = in4148 D61 = lOrF D62 = lOOFF Terminal 64 is connected to the standard rear brake light circuit and terminal 65 is connected to the high intensity brake light 7.
The left and right brake lights of the vehicle are prevented from illuminating when the warning device is activated by means of two J-PAD5 SLX low leakage diodes D20 (one shown in figure 6D) fitted into the existing brake light circuit as input voltage protection. When the foot brake of the vehicle is applied, the left, right and highintensity brake lights are illuminated, any flashing of the high-intensity brake light 7 being momentarily overridden.
Figure 7 schematically shows a second embodiment of the invention which comprises a front warning device. A voltage regulator 75 is connected to a proximity detector 72 mounted on the front of the vehicle. Both of these devices are the same as the counterpart devices (16) in the first embodiment. The proximity detector is connected via an amplifier 73 to an 80dB 12V buzzer 29 and a lowintensity warning lamp 30, both of which are mounted in the driving compartment. The front warning device is for use in conditions of reduced visibility and is activated whenever the vehicle's high intensity fog lights and ignition are switched on together. This device is not speed dependent.
The proximity detector 72 detects obstacles within a safety envelope of 22m (75') in the path of the vehicle.
This range can be varied by selecting a resistor R20 shown in Figure 6C, which determines a time delay occurring between detection of an obstacle and operation of the warning components, during which time the distance to the obstacle will have shortened. The variation from standard conditions is amplified and used to sound the buzzer 29 and illuminate the warning lamp 30, thus alerting the driver to the presence of an object within the 22 metre safety envelope.
The buzzer and warning lamp remain activated as long as the obstacle remains within the safety envelope.
It will be appreciated that the invention, as described above, provides an efficient and inexpensive automatic system for warning against the risk of collision which results from vehicles following each other too closely. However, the front warning device is not intended as a substitute for driver awareness and good driving practice in conditions of reduced visibility.
Alternative proximity detectors to the microwave radar detector described above may be used in the invention. Figure 8 shows an ultrasonic proximity detector using a distance proportional transducer 31 which has an inbuilt pulse width proportional output of 0.5V or 0.5mA with temperature compensation as a distance transmitter.
The transducer operates at 40kHz with a cone width of 5 , switching time 200ms, settling time ls, linearity + 50mm and temperature stability from -100C to +600C.
Figure 9 shows an infrared proximity detector which uses a type SFH750 infrared emitting diode 32 and a type
SFH250 filter detector diode 33. Alternatively, a Heimann
LH1954 pyroelectric passive infrared emitting diode and an
NPN silicon phototransistor may be used, mounted in one housing on parallel axes. The diode and phototransistor are moulded in infrared transmissive plastics material which reduces ambient light. The phototransistor responds to radiation from the infrared emitting diode only when a reflective object passes into the field of view.
It is considered that a detailed description of the circuits shown in Figures 8 and 9 is unnecessary, their operation being apparent to those skilled in the art. The following components are common to the circuits of Figures 6A to 6C, 8 and 9: R1 = 3.9kQ R2, R15, R16 = lkQ R3 = 82kQ R4 = 5lkQ R5 = 150kQ R6 = 4.7M# R7, R17 = 470Q
R8, Rll, R19 = lOkQ R9 = 2.2kQ R10 = 470kQ R12, R13 = 220kQ
R14 = R18 = 220# R20 = 47kQ RV1 = 470kQ variable resistor
C1, C10 = 100nF
C2, C12 = l00\F C3, C6, C9 = 1 > F 35V C5 = 47nF Cli = lOpF 50V
D1, D2 = lN4148/iN5822 D3 = iN4001 LED1 = MINI 3mm LED
TR1, TR2 = BC548
TR3 = BD139 TR4 = BC109C
TR5 = BD131 5 = Power stabiliser (see Figure 5)
15 = WA741C 25 = Low pass filter
26 = Variable gain amplifier
All the externally mounted parts of the warning device are encapsulated in a waterproof manner to the IP65 (DIN40050) standard.
The warning device may be modified by providing a circuit for varying the detection range or safety envelope depending on the speed of the vehicle. In the modified device, the millivolt output 14 of the speed sensor 2 is applied via an interpreter to the input circuit of the transceiver 38 in order to control the power supplied thereto. The speed-dependent detection range takes account of the fact that the stopping distance which should be maintained between two vehicles is larger at higher speeds.
Claims (21)
1. An inter-vehicle proximity warning device for mounting in a vehicle, said device including beam projecting means, beam detecting means for detecting a reflection of the beam from an object located within a specified distance which is at least lOm from the beam detecting means, and warning means responsive to the beam detecting means to indicate the presence of such an object.
2. A device as claimed in claim 1, wherein said specified distance is as least 20 metres from the beam detecting means.
3. A device as claimed in claim 1 or 2, including vehicle speed dependent means for varying said specified distance.
4. A device as claimed in claim 1, 2 or 3, wherein said beam projecting means and beam detecting means comprise a Gunn oscillator and a mixer diode respectively.
5. A device as claimed in claim 1, 2 or 3, wherein said beam projecting means and beam detecting means comprise an ultrasonic transducer.
6. A device as claimed in claim 1, 2 or 3, wherein said beam projecting means comprises an infrared emitting diode and said beam detecting means comprises a filter detector diode or a phototransistor.
7. A device as claimed in any preceding claim, wherein said warning means includes at least one visible warning unit.
8. A device as claimed in claim 7, wherein said warning means includes a red light for warning a following vehicle.
9. A device as claimed in claim 8, including means for intermittently illuminating the red light.
10. A device as claimed in any preceding claim, including vehicle steering sensing means for preventing actuation of the warning means when a vehicle to which the device is fitted is turning more than a predetermined amount.
11. A device as claimed in claim 10 wherein the steering sensing means includes steering wheel rotation sensing means which detects steering wheel rotation of more than a predetermined angle.
12. A device as claimed in claim 11, wherein the predetermined angle is greater than 150.
13. A device as claimed in any preceding claim, including a speed sensing arrangement for deactivating the device when a vehicle to which the device is fitted is travelling at less than a predetermined speed.
14. A device as claimed in claim 7, wherein said warning means includes a dashboard mountable light.
15. A device as claimed in any of claims 1 to 7 or claim 14 wherein said warning means include an audible warning unit.
16. A device as claimed in any of claims 1 to 7, 14 or 15, including means for activating the device in response to the activation of vehicle fog lights.
17. A vehicle including an inter-vehicle proximity warning device as claimed in any preceding claim.
18. A vehicle including an inter-vehicle proximity warning device as claimed in any of claims 1 to 13, the beam projecting means and beam detecting means being mounted at the rear of the vehicle for detecting a following vehicle.
19. A vehicle as claimed in claim 18, when dependent upon claim 9, wherein the red light serves as a vehicle brake light and the device includes means for overriding the intermittent illumination of the red light in response to actuation of a vehicle brake light circuit.
20. A vehicle including an inter-vehicle proximity warning device as claimed in any of claims 1 to 7 or 14 to 16, wherein the beam projecting means and beam detecting means are mounted so as to detect an obstacle in front of the vehicle.
21. An inter-vehicle proximity warning device substantially as herein described with reference to the accompanying Figures.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9503982A GB2298540A (en) | 1995-02-28 | 1995-02-28 | Inter-vehicle proximity warning device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9503982A GB2298540A (en) | 1995-02-28 | 1995-02-28 | Inter-vehicle proximity warning device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9503982D0 GB9503982D0 (en) | 1995-04-19 |
| GB2298540A true GB2298540A (en) | 1996-09-04 |
Family
ID=10770379
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9503982A Withdrawn GB2298540A (en) | 1995-02-28 | 1995-02-28 | Inter-vehicle proximity warning device |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2298540A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2038132A (en) * | 1978-11-14 | 1980-07-16 | Burling G T | Distance indicating system |
| EP0210079A2 (en) * | 1985-07-24 | 1987-01-28 | John W. Davis | Automotive collision avoidance and/or air bag deployment radar |
| GB2222710A (en) * | 1988-09-09 | 1990-03-14 | John Home | Vehicle monitoring systems |
| GB2254509A (en) * | 1991-04-02 | 1992-10-07 | William Clark | Safety device for a vehicle |
-
1995
- 1995-02-28 GB GB9503982A patent/GB2298540A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2038132A (en) * | 1978-11-14 | 1980-07-16 | Burling G T | Distance indicating system |
| EP0210079A2 (en) * | 1985-07-24 | 1987-01-28 | John W. Davis | Automotive collision avoidance and/or air bag deployment radar |
| GB2222710A (en) * | 1988-09-09 | 1990-03-14 | John Home | Vehicle monitoring systems |
| GB2254509A (en) * | 1991-04-02 | 1992-10-07 | William Clark | Safety device for a vehicle |
Non-Patent Citations (1)
| Title |
|---|
| New Scientist 15 August 1985 page 27 * |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9503982D0 (en) | 1995-04-19 |
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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) |