EP0975991A4 - Doppler radar warning system - Google Patents

Doppler radar warning system

Info

Publication number
EP0975991A4
EP0975991A4 EP98920848A EP98920848A EP0975991A4 EP 0975991 A4 EP0975991 A4 EP 0975991A4 EP 98920848 A EP98920848 A EP 98920848A EP 98920848 A EP98920848 A EP 98920848A EP 0975991 A4 EP0975991 A4 EP 0975991A4
Authority
EP
European Patent Office
Prior art keywords
signal
transceiver
distance
signals
vehicle
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Withdrawn
Application number
EP98920848A
Other languages
German (de)
French (fr)
Other versions
EP0975991A1 (en
Inventor
Benny Hsu
Maw-Rong Chin
James Chun Chen
Shunjen Gene Houng
William Chung-Hay Ngai
Pang Yu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Microtek International Inc
Original Assignee
Microtek International Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Microtek International Inc filed Critical Microtek International Inc
Publication of EP0975991A1 publication Critical patent/EP0975991A1/en
Publication of EP0975991A4 publication Critical patent/EP0975991A4/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
    • B60Q9/00—Arrangement or adaptation of signal devices not provided for in one of main groups B60Q1/00 - B60Q7/00, e.g. haptic signalling
    • B60Q9/002—Arrangement or adaptation of signal devices not provided for in one of main groups B60Q1/00 - B60Q7/00, e.g. haptic signalling for parking purposes, e.g. for warning the driver that his vehicle has contacted or is about to contact an obstacle
    • B60Q9/004—Arrangement or adaptation of signal devices not provided for in one of main groups B60Q1/00 - B60Q7/00, e.g. haptic signalling for parking purposes, e.g. for warning the driver that his vehicle has contacted or is about to contact an obstacle using wave sensors
    • B60Q9/005—Arrangement or adaptation of signal devices not provided for in one of main groups B60Q1/00 - B60Q7/00, e.g. haptic signalling for parking purposes, e.g. for warning the driver that his vehicle has contacted or is about to contact an obstacle using wave sensors using a video camera
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
    • B60Q9/00—Arrangement or adaptation of signal devices not provided for in one of main groups B60Q1/00 - B60Q7/00, e.g. haptic signalling
    • B60Q9/002—Arrangement or adaptation of signal devices not provided for in one of main groups B60Q1/00 - B60Q7/00, e.g. haptic signalling for parking purposes, e.g. for warning the driver that his vehicle has contacted or is about to contact an obstacle
    • B60Q9/007—Arrangement or adaptation of signal devices not provided for in one of main groups B60Q1/00 - B60Q7/00, e.g. haptic signalling for parking purposes, e.g. for warning the driver that his vehicle has contacted or is about to contact an obstacle providing information about the distance to an obstacle, e.g. varying sound
    • 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
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • 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
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • G01S13/583—Velocity or trajectory determination systems; Sense-of-movement determination systems using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets
    • G01S13/584—Velocity or trajectory determination systems; Sense-of-movement determination systems using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets adapted for simultaneous range and velocity measurements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/86—Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/86—Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
    • G01S13/867—Combination of radar systems with cameras
    • 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
    • G01S13/87—Combinations of radar systems, e.g. primary radar and secondary radar
    • 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
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/93—Sonar systems specially adapted for specific applications for anti-collision purposes
    • G01S15/931—Sonar 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
    • G01S13/93—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
    • G01S2013/9314—Parking operations
    • 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
    • G01S2013/9315—Monitoring blind spots
    • 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
    • G01S2013/9317—Driving backwards
    • 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
    • G01S2013/9323—Alternative operation using light waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • 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
    • G01S2013/9324—Alternative operation using ultrasonic waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • 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
    • 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
    • G01S2013/93274—Sensor installation details on the side 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
    • G01S2013/93275—Sensor installation details in the bumper area
    • 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
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/88—Sonar systems specially adapted for specific applications
    • G01S15/93—Sonar systems specially adapted for specific applications for anti-collision purposes
    • G01S15/931—Sonar systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G01S2015/932—Sonar systems specially adapted for specific applications for anti-collision purposes of land vehicles for parking operations
    • G01S2015/933—Sonar systems specially adapted for specific applications for anti-collision purposes of land vehicles for parking operations for measuring the dimensions of the parking space when driving past
    • G01S2015/936—Sonar systems specially adapted for specific applications for anti-collision purposes of land vehicles for parking operations for measuring the dimensions of the parking space when driving past for measuring parking spaces extending transverse or diagonal to the driving direction, i.e. not parallel to the driving 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
    • 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
    • G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
    • G01S7/032—Constructional details for solid-state radar subsystems
    • 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
    • G01S7/35—Details of non-pulse systems

Definitions

  • the present invention relates to a Doppler radar that may be incorporated into automotive, residential, business, and other warning systems, and to a fully integrated automotive and/or building safety warning system with three-dimensional features using the combined technologies of real-time video, camera and a smart Doppler radar.
  • Doppler radar also known as the Doppler effect
  • Doppler effect is well known, as explained, for example, in M.I. Skolnik, "Introduction to Radar Systems", McGraw-Hill, 1980, Chapter 3, CW and Frequency-Modulated Radar.
  • Warning systems including vehicular warning systems which implement Doppler radar, have been described in U.S. Patent Nos. 3,863,253 ("'253") and 5,087,918 ('"918").
  • the '253 system is an analog system which converts the Doppler signals corresponding to two signals transmitted from the vehicle and returned as echo signals from the object into two rectangular signals, an exclusive OR gate which receives the two rectangular signals for producing pulses each appearing at a time when either of the rectangular signals appear, and an averaging circuit to produce a signal representative of the distance between the vehicle and the object.
  • the '918 system provides object range resolution, detection of both stationary and moving objects, and resolution of multiple objects, through use of six radio frequency heads that transmit and receive radar signals of both frequency- modulated continuous wave type and two-frequency Doppler type signals.
  • detection of an object is signaled by a visual indicator and an audible indicator.
  • Doppler radar to detect objects nearby, and the object's distance and relative speed.
  • Figure 1 is a block drawing showing the components of a preferred embodiment of the Doppler radar system of the present invention.
  • Figure 2 is a diagram showing the phase relation of the signals used in the Doppler radar of Figure 1.
  • Figure 3 is a block diagram showing the phase comparator of Figure 1.
  • FIG. 4 is a block diagram showing the digital filter of the digital signal processor of Figure 1.
  • Figure 5A is a schematic circuit diagram of the trans- mitter/receiver module of the Figure 1 embodiment.
  • Figure 5B is a reproduction of the mask work of the circuit the transmitter/receiver module of the Figure 1 embodiment.
  • Figure 6 is a reproduction of the mask work of the trans- mitting and receiving antenna of the Figure 1 embodiment.
  • Figure 7 is a schematic diagram showing the relationship of the radar beams and reflectors used in the Figure 1 embodiment system.
  • Figure 8 is a block diagram showing the relationship of a target-to-zones in relation to the Figure 1 embodiment.
  • Figure 9 is a schematic diagram showing a cone of coverage, together with reference coordinates for the radar beams of the Figure 1 embodiment.
  • Figure 10 is a schematic diagram showing the Figure 9 cone and including coordinates for objects in three zones within the cone.
  • Figure 11 is a schematic diagram showing two transmitter/ receiver units together with a digital signal processing and display unit of the Figure 1 embodiment.
  • Figure 12 is an exploded perspective view of a transmitter/receiver unit of Figure 11.
  • Figure 13 is an exploded perspective view of the digital signal processing and display unit of the Figure 1 embodiment.
  • Figure 14 is an exploded, rear perspective view of the Figure 13 unit.
  • Figure 15 is a schematic view of a vehicle illustrating the positioning of a transmitter/receiver unit of Figure 12 for the Figure 1 embodiment.
  • Figure 16 is a rear view of Figure 15 vehicle, showing two transmitter/receiver units.
  • Figure 17 is a top schematic view showing two transmitter/receiver units positioned at the rear of a truck.
  • Figure 18 is a side, cross-sectional view of a bracket used to retain a transmitter/receiver unit of Figure 12.
  • Figure 19 is a front view of the Figure 18 bracket and transmitter/receiver unit.
  • Figure 20 is a schematic drawing showing the components of an alternate preferred embodiment of the present system including displays, a processor and sensors.
  • Figure 21 is a top schematic view of a vehicle showing the position of transceivers and display devices for another preferred embodiment of the present invention.
  • Figure 22 is a schematic view of a vehicle showing the positioning of transceivers of the present invention in another alternate embodiment.
  • Figure 23 is a schematic view of a vehicle with trans- ceivers of the present invention placed in alternate positions in another alternate embodiment, and showing the vehicle in a parking environment and with an alternate display device.
  • Figure 24 is a schematic diagram of a vehicle showing transceivers placed in the side of the vehicle and in an envi- ronment where another vehicle is approaching the first vehicle from the side.
  • Figure 25 is a schematic diagram showing the use of the present invention as a security warning device wherein signals from the approaching target are transmitted to a remote video telephone.
  • Figure 26 illustrates the present invention as placed on a building above a door way.
  • Figure 27 illustrates the present invention in an embodiment in which three transceivers of the present invention are positioned at various locations on a building to provide a wide area surveillance capability.
  • Figure 28 is a flow diagram of the main routine for the computer implemented software for the Figure 1 embodiment.
  • Figures 29A-29D are flow diagrams of sub-routines of the main routine for the computer implemented software for the Figure 1 embodiment.
  • Figure 30 is a schematic diagram showing the relationship of the Doppler-shifted signals in a manner to facilitate understanding of the conversions from frequency to period for the Doppler-shifted signals, of the relationship of the terminology used in the software routine in comparison to the other portions of the description of the invention and the manner in which forward and reverse directions are determined.
  • the preferred embodiment described herein includes a computer software implementation based on an 8-bit microprocessor, such as for example a Z86E31, manufactured by Zilog. It is recognized that the principles of the present invention may be used with other processors.
  • One of the advantages achieved by the present invention is the capability of providing a Doppler radar system which is implemented with relatively simple, inexpensive components, such as, for example, an 8-bit microprocessor.
  • FIG 1 provides a block diagram illustration of a Dop- pier radar warning system of the present invention.
  • Doppler radar unit or system 30 includes a transmitter 32 and a receiver 34 which together are referred to as the transceiver.
  • the transceiver components are concluded in a module 31.
  • the preferred circuit which is illustrated in Figures 5A and 5B, as will be described in greater detail.
  • the transmitter 32 includes a voltage-controlled oscillator (“VCO”) 36 and a frequency-shifted keying modulator (“FSK”) 38.
  • VCO voltage-controlled oscillator
  • FSK frequency-shifted keying modulator
  • the VCO 36 is a radio-frequency ("RF") oscillator whose oscillating frequency is determined by a controlled voltage.
  • VCOs of the type used in the present invention are commercially available and the oscillating frequency as used in the present invention is chosen to be within the 5.8 GHz ISM frequency band.
  • the ISM frequency band is the U.S. government Federal Communication Commission allocated frequency band for industrial, sci- entific and medical applications and for which no license is required.
  • the FSK modulator 38 is a conventional square wave generator whose output voltage wave form is sent through line 39 and used to control the VCO to produce two distinct frequencies at F 0 ⁇ ⁇ F, in a conventional manner.
  • FSK modulators are commercially available and, for the purpose of the present invention the preferred range of frequencies which may be used for F 0 are within the range of 5.725 GHz to 5.850 GHz. Also, within the scope of the present invention, the preferred range of change of frequencies, ⁇ F, is from 1 MHz to 2 MHz.
  • the FSK modulator 38 simultaneously provides a signal through line 37 to control the demultiplexer ("DE-MUX") circuit 54 in the receiver 34 to recover two Doppler echo signals reflected from the moving target or object 42.
  • the trans- mitter 32 also includes a transmitter antenna 40 ("Tx") which receives the VCO signal output through line 41 and radiates the RF energy toward the object 42.
  • the receiver 34 includes a receiver antenna (“Rx”) 44 which receives the reflected RF energy from the object 42. This reflected energy, the echo, is at a different apparent frequency due to the Doppler effect, as is well known.
  • the analog signal from the Rx antenna 44 is then sent through line 43 to low noise amplifier (“LNA”) 46 which amplifies the received RF signal by a factor of approximately 10.
  • LNA low noise amplifier
  • the am- plified RF signal is then sent via line 45 to a mixer 48, which produces an intermediate frequency (“IF”) analog signal from the product of the transmitted and received signals.
  • the mixer 48 is a circuit which converts high frequency energy into a lower, intermediate frequency energy in a conventional fashion, by subtracting the frequency of the echo signal from the frequency of the transmitted signal.
  • the analog IF signal which is representative of the Doppler shift, or effect, is then sent via line 47 to the IF amplifier 52 which amplifies the IF signal by a factor of approximately 1,000.
  • the IF amplifier 52 is a conventional analog amplifier.
  • the amplified IF signal is then sent via line 53 to the demultiplexer circuit 54, which separates the two mixed, amplified Doppler shifted signals reflected from the object.
  • These two Doppler signals are referred to as signal S, which is the Doppler shifted signal which had been transmitted at F 0 + ⁇ F.
  • the second signal, referred to as S 2 is the Doppler shifted signal which had been transmitted at frequency F 0 - ⁇ F.
  • phase comparator 60 converts these analog signals to digital signals and determines the phase difference, referred to as ⁇ , between the two Doppler signals S ! and S 2 .
  • the phase difference, ⁇ is represented by a digital signal which is then sent via line 61 from the phase comparator 60 to the digital signal processor ("DSP") 62.
  • DSP digital signal processor
  • the DSP 62 calculates the object distance, i.e.. range or "R" from the object to the antenna by using the phase difference ⁇ , and the known rela- tionship that the distance "R” is directly proportional to the phase difference.
  • the DSP software is represented schematically at 55 in Figure 1.
  • the DSP also includes a digital filter 63 which filters out unwanted noise and minimizes the number of false alarms.
  • Digital signals representing the calcu- lated distance R are then sent to displays; for example, a light display 64 and an audio display such as a beeper 66.
  • the number of lights energized in the display is in inverse proportion to the distance R.
  • the beeper has a sounding frequency which is inversely proportional to the dis- tance R.
  • Other displays may be used, such as numerical displays of distance, voice statements of distances, etc.
  • the vertical axis represents an analog signal amplitude at ⁇ voltages, with the horizontal axis representing time.
  • the signal S is shown crossing the 0-voltage line at T, and T 3 as signal S, increases in voltage from 0 volt to its maximum voltage and then decreases again to 0 volt.
  • the signal S 2 is at 0-voltage, the "signal 0" at T 2 which is some time later than the T, at which the signal S, has its signal 0.
  • This relationship is preferably implemented in the application software, flow diagrams of which are illustrated in Figures 28 and 29 -D.
  • FIG 3 is a block diagram of the phase comparator 60, which is preferably implemented with the digital signal processor application software, and which includes two conven- tional signal 0 crossing detectors that initiate interrupt requests to the digital processor software routine at 0-crossing T, , T 2 , T 3 , etc., as shown in Figure 2.
  • the zero crossing detectors are typically included in microprocessor chips of the size for which this invention is intended.
  • the analog signals are thereby converted to digital signals, and further processed by the DSP software.
  • the signal S ! is monitored by the 0 crossing detector 72, and when signal S, crosses the 0-voltage condition, interrupt requests are sent to the digital processor for determination of the 0-crossing times at T, and T 3 , as shown at 76, " for signal S,.
  • 0-crossing detector 74 monitors signal S 2 and provides an interrupt request to the digital processor for reading the 0- crossing T 2 of signal S 2 .
  • the phase difference ⁇ is directly proportional to the range of an object from the transmitter antenna 40.
  • the DSP also de- termines speed information in accordance with this relationship.
  • the digital filtering feature of the present invention is shown schematically at 63.
  • This filtering function is preferably implemented in the applica- tion software and functions to reduce noise and minimize false alarms.
  • Input signal 82 which is representative of the range, R.
  • the digital filter 63 may be referred to as a feedback loop, and with the flow chart for the preferred embodiment being shown in Figure 29A-D.
  • the filter 63 has the raw, unfiltered signal 82, i.e., S(82) as its input.
  • N is an integer, found to be in a useful range of from 1 to 10.
  • the preferred values of N are 4, 5, 6, 7 and 8.
  • the value 6 is the most preferred value for N in regard to the first embodiment. It has been discovered that N values of 1, 2 or 3 tend to yield an insufficient reduction in noise and too many false alarms. N values of 8 , 9 and 10 tend to yield more noise reduction, but the response time is too slow. Also, it is emphasized that the particular choice for an N value depends on the particular application for which the warning system is to be used. The preferred value of 6 has been found to be the best choice for the vehicular warning system of the first embodiment of the present invention.
  • the divided signal, S(87) then has added to it the signal S(92) at node 88 to yield the signal R' , at 96, which more ac- curately represents the final estimated range.
  • the R' signal is also returned to the feedback loop at 90, and through line 92 is added at node 88 to S(87) and through line 94 is subtracted from S(82) at 84.
  • the signal R 1 shown at 96 is output and is a representation of the final, estimated distance or R from the object to the transmitter antenna. This signal may be then sent to conventional displays using conventional techniques. Referring to the Figure 5A schematic circuit diagram, the circuit for transmitter-receiver module 31 will be described.
  • the module 31 includes the circuitry shown in Figure 1 and described above.
  • VCO 31 is represented by transistor 356 which is an FET transistor, preferably Hewlett Packard Part No. ATF- 13786.
  • the LNA 46 is shown at 328 and is an integrated circuit with Hewlett Packard Part No. MG886563.
  • the mixer 48 is shown at 335 in Figure 5 and includes diodes 336 and 338, with Hewlett Packard Part Nos. HSMS2852 for both diodes which are typically commercially available as a single package which contains the two diodes.
  • the VCO 36 includes transistor 356 and Varactor diode 360.
  • the diode 360 is, preferably, Siemens Part No.
  • BBY5203W and the transistor 356 is preferably a Hewlett Packard Part No. ATF-13786.
  • These above-mentioned components form the active components in the circuit, with the remaining components being typical, passive components including various capacitors and resistors and a microwave transmission line shown at components 342, 340, 356, 344, 352, 374, 372.
  • the FSK modulator 38 generates a 50 KHz square wave, as shown at 304 in Figure 5A.
  • the signal then is transmitted to and through resister 390 which is a 50K OHM resistor and then to the variable resistor 392 which is a 5K OHM vari- able resistor.
  • the signal proceeds through a capacitor 394 which is preferably a .IMF (micro Farad).
  • the signal then is transmitted to a node and is split, part of which goes to ground through resistor 376 which is a 100K OHM resistor.
  • the signal also goes to the next branch downward as shown in Figure 5A through resistor 375 which is a 10K OHM resistor and goes into the Varactor diode 360, which functions in a conventional fashion to modulate the frequency.
  • Downstream of the capacitor the signal then goes to ground through resistor 358 which is a 10K OHM resistor and into the gate of transistor 356.
  • the source of transistor 356 then is connected to ground via resistor 354 which is a 22 OHM resistor.
  • the drain side of transistor 356 then connects to capacitor 362 which is a 7 Pico Farad capacitor and makes a complete circle back to the Varactor diode 360.
  • the drain of transistor 356 is also the power output, the major portion of the power output passing through capacitor 364 which is a 7 Pico Farad capacitor and then through the power divider shown at 367, and, as represented in the Region 1 on the Figure 5 B transmitter/ receiver module PCB design.
  • One portion of the power is then sent to the transmitting antenna connecting point 370 as shown in Figures 5A and 5B and then to antenna 40 as shown in Figure 1.
  • the line 366 in Figure 5A represents a tuning stub.
  • the remaining power then is sent through the opposite line of the branch and into the mixer 335 in Figure 5A, and shown at 48 in Figure 1.
  • connection point 324 to the receiving antenna 44 connects adjacent the antenna 44 as shown in Figure 1.
  • the Doppler shifted signal which is returned from the target or object 42 then is transmitted down the line and through capacitor 332 which is a 33 Pico Farad capacitor.
  • the signal then enters the LNA 328 as shown in Figure 5A, and referred to as 46 in Figure 1.
  • the signal output from the low noise amplifier 328 is then passed through capacitor 330 which is a 10 Pico Farad capacitor and from there through resistor 334 which is preferably a 10 OHM resistor and from there into the mixer 335 as shown in Figure 5A.
  • Line 340 represents a tuning stub.
  • the output from the low noise amplifier 328 also is sent to a matching network 325 via the line and resistor 326, which is preferably a 68 OHM resistor.
  • the matching circuit includes the transmission line illustrated schematically at 342 and shown in detail in the PCB design of Figure 5B. Of i por- tance, it is noted that one branch of the transmission line 342 includes a conventional microstrip line which is 20 mil. wide and 250 mil. long.
  • the matching network also includes a 1 Pico Farad capacitor 322 which is connected to ground and a second 0.01 MF (micro Farad) capacitor 320 which is also connected to ground.
  • a +5 volt DC voltage is applied to voltage divider circuit which includes resistor 384, a 10K OHM resistor, resistor 388 which is a 10K resistor, resistor 386 which is a 10K resistor and variable resistor 382 which is a 100K OHM variable resistor, and then through resistor 380 which is a 1 MEG OHM resistor and then goes into transistor 378 which is commonly available transistor, Part No. BCW60D.
  • One output of the transistor 378 goes to line 379 and it is here where the frequency F 0 is set up. Referring to line 381, downstream from the capacitor 394, the ⁇ F is determined, thus at transistor 356 the frequency F + or - ⁇ F is alternatingly produced.
  • this part of the circuit uses a DC voltage to produce the desired frequency F 0 + or - ⁇ F.
  • reference numeral 302, 308, 310 and 314 are connections to ground in accordance with standard microwave design practice. The connections points 316 and 318 are not connected in the preferred embodiment.
  • transmitter-receiver module printed circuit board design it is noted that this is an enlargement of the actual mask for the transmitter-receiver module 31 as shown in Figure 1. The exact proportions and dimensions shown therein embody the preferred microwave design for the embodiment for the Figure 1 embodiment shown at reference numeral 31 in Figure 1.
  • each antenna is of a trian- gular shape.
  • the antenna substrate material is FR4 , as commonly referred to in the field of microwave technology.
  • the preferred substrate thickness is 32 mils.
  • Transmitting antenna 40 connected to the system 30, has a first plane reflector 98 and a second plane reflector 100, with included angle ⁇ therebetween.
  • Each of the reflectors 98 and 100 may be rotated about a vertical axis 102, 103 to form an adjustable radial wave guide 104.
  • the included angle ⁇ may be adjusted to vary the beam width of beam A.
  • the orientation of the radial wave guide 104 can be varied to steer the beam. As shown in Figure 7, which is a top view, increasing ⁇ would widen beam A. Movement of the entire wave guide 104 to the left or right would move beam A and beam B to the left or right.
  • a block diagram of the receiving antenna, target or object and warning device of the present invention will be described.
  • a series of zones has been defined as representing a range of distances from the antenna.
  • the DSP can be programmed to detect objects located in a predetermined zone. For example, the object in zone 2 would be detected, and all other zones would be ig- nored. Multi-zones, such as zones 2 and 5 (not shown) , or zones 1, 3 and 6 (not shown) could be assigned for detection, and other zones ignored.
  • the antenna receives a reflected signal from the target 42, sends it to the radar transceiver 31 via antenna 44, then to the digital signal processor 62, and ultimately to the visual/audio warning devices 64, 66.
  • Figures 9 and 10 illustrate the concept of a cone within which objects may be identified and their ranges from the antenna may be determined through use of a coordinate system.
  • a truncated cone 106 is shown as ex- tending outward from its narrow end, which terminates at the transmitting/receiving antenna unit 108 of the warning system, and outward to some predetermined distance.
  • an X, Y, Z coordinate system is established, with the antenna unit being the center of the coordinate system, the X direction being left-to-right from the center point of the antenna and facing in the direction of the transmitted beam.
  • the Y direction is vertical, and the +Z direction is the horizontal direction of the transmission.
  • zone 2 would be that region within the cone between Z, and Z 2 ; and zone 3 would be that region inside of the cone between Z value Z 2 and Z 3 .
  • the Doppler radar warning system is incorporated into a vehicular safety warning system having two transmitters and receivers connected to a single digital signal processor and display unit.
  • the first transceiver unit 108 is shown with mounting brackets 110, 112, mounting plate 114 and radar transmitting antenna 40 and radar receiving antenna 44 shown respectively.
  • the preferred antenna is made of a metallic patch and is of a triangular configuration measuring about 0.6 inch at each side as shown in Figure 6 and further described above. Other materials, sizes and shapes, of course, may be used, or will be appreciated by those skilled in this field, and are considered to be equivalent.
  • Signal cord 116 is shown leading from the transceiver unit 108.
  • the transceiver unit 108 may be combined with other transceiver units as input, for example, unit 118 which is identical to unit 108.
  • Signal input lines 116 and 120 are shown as receiving signals from either a signal transceiver unit 108, 118, respectively, or multiple transceiver units via lines 122, 124.
  • the signals are input to the visual/audio warning device, as shown at 126. It is envisioned that transceiver units such as shown in Figure 11 would be placed, for example, on the left and right areas of the front and/or back and/or sides of a vehicle such as a car, truck or other vehicle.
  • the unit includes a housing 128, mounting brackets, a back plate 132, an antenna holding substrate 134, upon which the transceiver printed circuit board circuit 31 is held, a receiving antenna 44, a transmitting antenna 40, antenna holding brackets 136, 138 and signal processing cord 116.
  • the housing also includes a front cover 140 which may be sized and shaped to form any convenient shape, such as to simulate a head lamp or some other part of the vehicle to camouflage its identity as a radar transceiver.
  • the transceiver housing is made of a durable plas- tic and is of a type for which the radar signals may pass easily therethrough.
  • the transceiver units are positioned behind nonmetallic bumper (s) of the vehicle. In this way they are highly protected and camouflaged, but are fully functional.
  • the display 126 includes a main housing 142 portion and a top housing 144 portion.
  • a front plate 146 provides for a plurality of light emitting diodes and a speaker 164 for display of the visual and audio signals from the digital signal processor.
  • An audio volume control is shown at 165.
  • LEDs light emitting diodes
  • four LEDs 148, 150, 152 and 154 are shown with corresponding light paths indicated at 156, 158, 160 and 162.
  • Pin connections 166, 168 are located at the rear of the unit to receive signal wires 116, 120.
  • the preferred software application for the present invention will be de- scribed.
  • This application is capable to determine distances in the case when the object is moving toward the transceiver, i.e.. the forward, or advancing direction, as well as when the object is moving away from the transceiver, i.e.. the reverse or retracting direction.
  • the signals S, and S 2 as shown in Figure 2, it is noted that this relationship occurs when the object is moving away from the transceiver.
  • a schematic representation of the signals along the time axis in the case when the object and the transceiver are moving toward each other is shown.
  • Figure 30 includes a square wave representation of the signals with the designators "H” and "L” referring to the distance between S, old and S 2 old and the distance H + L is represented by S 2 new - S 2 old.
  • the distance ratio then may be expressed as H ⁇ (H + L) .
  • H/(H + L) (S, old Time - S 2 old Time) ⁇ (S 2 new Time - S 2 old Time) .
  • the relationship is expressed by simply swapping H and L to yield the ratio L ⁇ (L + H) and the distance ratio then may be expressed as L/(L + H) .
  • software routine which is implemented on a Z86E31 IC chip, the routine begins at step 502 with power being supplied to the chip. Then, at step 504, the chip is initialized with the variable RDY set equal to 0. Next, at step 506, the main program waits for an interrupt, which interrupt comes in when the S, signal crosses the 0-volt condition.
  • step 510 the RDY register is set equal to 1 at step 510.
  • step 512 the program checks to determine whether the RDY register is set equal to 1. If no, then the program returns to the wait for interrupt condition at 506. If the RDY register equals 1, then the main program continues to step 514 where the RDY register is reset to 0, so that when either the program is restarted or is returned to step 506, the RDY register is set at 0. After clearing the RDY register to 0, next the program performs the calculation which determines the ratio used in the distance calculation at step 516 and, as will be explained later in greater detail in regard to the calculation subroutine.
  • step 518 the distance value resulting from step 518 in the forward, that is, the condition when the target and transceiver are moving towards each other, is a distance from which the number 1 is subtracted. It has been found that in the vehicular system of the first embodiment, the value 1 yields best results and is therefore preferred. For other applications a different number might be used instead of 1. In the case where the object and the transceiver are moving away from each other, the dis- tance figure resulting from step 518 is left unchanged.
  • the value calculated in step 520 is then sent to the filter subroutine, represented as step 522, in Figure 28.
  • the filter subroutine in general, provides a loop or feedback calculation in which noise and false alarms are minimized.
  • the filtered distance is represented by a variable named DF.
  • the final value of the DF variable is stored in a register which is set equal to a DF initial value plus the value of the distance from step 520 minus the initial DF value ⁇ 6.
  • a value of 7.0 for the DF initial value is most preferred, and that the most preferred number in the denominator is 6.
  • the number 6 in the denominator in step 522 corresponds to the value N as set forth at 86 in Figure 4. As described above, this value is an integer, and is within the range of 1- 10. Specific applications will use different values for N, with the particular value chosen being an optimization for the particular application.
  • the DF final is sent to decision point 524 and checked to determine whether the DF value final is less than 0. If the value is less than 0, the main program returns to wait for interrupt 506, negative numbers having no significance in the present application. If the DF value final is 0 or a positive number, then the decision point 524 result is no and the signal energizes beeper 526 and the bar code visual display 528 and returns the main program to the wait for interrupt step 506.
  • the initial value of DF is set to 7 for the first calculation or first iteration through the main loop.
  • the initial DF for each subsequent loop is set to be equal to the final DF of the previous iteration.
  • the final DF is + 6.0.
  • the decision would be no, the beeper and bar code would be energized and the main loop would return to step 506 for the next S, interrupt.
  • next distance calculation entering step 522 would be filtered with the initial DF being 6.0 rather than 7.0 as in the previous iteration. In similar fashion each succeeding iteration of the main loop would then use new DFs.
  • step 516 the subroutine 516 will be described in regard to the calculation of the ratio as expressed in step 516 of Fi ure 28.
  • main loop 500 provides information to decision point 530 as shown. If the data is not ready, then the program returns to the main loop. If data is ready, then the decision is yes and the subroutine proceeds to step 532 where time, expressed as H + L is inverted and thereby converted to frequency. Also, in step 532, frequencies of less than 0.7 Hz are rejected as having no meaning for the present application. For signals that are not rejected at 532, they then proceed to step 534. Step 534 is referred to as a range gate.
  • range gate means that a distance or range between the transceiver and a proposed target or beginning of a zone is predetermined and set so that the system will perform calculations and the filtering functions only on reflected signals within the set range.
  • the range has been set at 8 feet, meaning that signals which have been processed through step 532 but indicate a distance of greater than 8 feet will be rejected, whereas signals that have passed through step 532 and indicate a distance of 8 feet or less will be further processed.
  • the range of 8.0 ' is most preferred for the present ap- plication, although it will be understood that different ranges may be chosen for different applications, and that a plurality of range gates may be used so that objects in different zones may be determined while objects in other zones may be ignored.
  • the decision is no in step 538 and the program then skips over step 536.
  • the decision at step 534 is yes, indicating that the object is 8' or closer to the transceiver, the program then goes to step 536 where signals greater than 300 Hz are also rejected as of no usefulness in the present application.
  • steps 534, 536 and 538 are useful by discarding unusable signals that would otherwise slow down and clutter up the program.
  • step 540 a reverse determination is made.
  • the decision at point 540 is yes and the program goes to step 542 where the variable is converted to be a ratio repre- sentative of L ⁇ (H + L) .
  • This ratio is rejected for cases in which this value is greater than 0.25.
  • the value of 0.25 has been determined to be most preferred for the present application, although it is recognized that other values may be chosen for other applications.
  • the decision at step 540 is no, indicating that the object is moving closer to the transceiver, then the variable is converted to be representative of H ⁇ (H + L) and in cases where this signal is greater than 0.25, all such values are also rejected.
  • the calculations in steps 542 and 544 are merely calculations of ratios. In the event where the ratio in step 542 is greater than 0.25 or where the ratio is greater than 0.25 in step 544, the signal is rejected as having no known useful purpose in the present application.
  • the signal is sent to dynamic rescaling step 546 in order to provide more useful and accurate information from the data collected.
  • the value for H is 2 bytes in size whereas in step 548 the value for H has been converted to a 1 byte value, and the technique of converting from the 2 byte to the 1 byte is a conventional dynamic re- scaling technique which takes place in step 546.
  • the rescaled ratio is set forth and expressed in step 548, with the example being the case of a forward direction of motion, i.e.. when the object and the transceiver are moving together.
  • step 548 the signal is then sent to step 550 which is a round off step and decision point.
  • step 550 the decimal part of the ratio of signal 548 is equal to or greater than .5, then the value is sent to round off step 552 and rounded off to the next highest integer.
  • the decimal part of the signal 548 is less than .5, then the decimal part of the ratio is discarded and only the integer remains.
  • step 558 then is sent to decision box 560 and steps 562 and 564 where again, the forward distance is determined to be the distance value from step 558 minus 1 in step 564 and the distance value in the case of a reverse di- rection is the distance value expressed in step 558 minus 0, which is another expression or a repeat of step 520 as explained above with respect to the main program 500.
  • step 566 a determination is made concerning whether the distance equals 0, and if the answer is no, then the program skips around step 568.
  • step 568 a conventional determination is made regarding whether the 0 signal is the result of noise. If the answer is yes, then the program returns to the main loop 500 and if the answer is no, the pro- gram continues to the part of the subroutine shown at Figure 29C.
  • step 570 the routine checks to see whether this is the first time after power on. If the answer is yes, then the program proceeds to step 572 where the variable DF is set equal to 7 , as explained previously.
  • the program then skips to decision point 574 decision point and at this point the pro- gram checks to determine the value of the distance calculated in steps 564 and 566 minus the initial value DF, which has been set initially to 0. If the distance minus the variable DF is less than 0, then the answer at 574 is yes and the program proceeds to step 576. If the answer is no at 574 indi- eating that distance minus DF is equal to or greater than 0, then the program proceeds to step 580.
  • step 576 the same calculation is performed except that the comparison is made to -1. If the value of distance minus DF is less than -1, then the answer is yes and the program proceeds to step 578. If the answer is no, the program then proceeds to step 582. In the case where step 578 is reached, then the variable is set to -1 and the program proceeds to step 582. Referring to decision box 580, the same calculation as set forth in step 574 is performed; however, the calculation is compared to the value +1. If the value is greater than +1 then the program proceeds to step 579 and if the answer is no, the program proceeds to step 582. In step 579, if the dis- tance minus DF is greater than +1, then the variable is set to +1 and the program proceeds to step 582.
  • step 582 a new variable, referred to as DFR, is set equal to the DFR initial plus (distance minus DF) .
  • DFR initial plus (distance minus DF) .
  • the final DFR is contained in a register and it is con- stantly updated as more iterations of the program take place.
  • the program then proceeds to step 584 as shown in Figure 29D.
  • step 584 the final value of DFR is compared to 0. If DFR is not greater than 0, then the program proceeds to step 594. If the value of DFR is less than 0, then the program proceeds to step 586.
  • step 594 the value of DFR is compared to 6 and if the value is greater than 6 the program proceeds to step 596 where the variable DF is set equal to DF + 1. If the answer is no in step 594, then the program proceeds to decision point 600. Returning to decision point 586, the variable DFR is compared to the value -6 as shown, and if the answer is no, the program proceeds to step 600. In the event the variable DFR is less than -6, then the program proceeds to step 590 where the variable DF is set equal to DF - 1 and the program proceeds to step 592 where the variable DFR is cleared, by setting it equal to 0, and the program then proceeds to step 600.
  • variable DF is compared to the value 0 and if the answer is yes, indicating that the vari- able DF is less than 0 the program returns to the main loop. If DF is equal to or greater than 0, then the program proceeds to the beeper 602 and the bar code 604 and the value of DF is displayed in an appropriate fashion such as volume or frequency of beeps and/or number or sequencing of lights, and is re- turned to the main loop 500 as shown in Figure 28 in the lower right corner where beeper step 526, bar code 528 are also shown, but with different reference numerals. In this case return to the main loop means that the program returns to step 506 waiting for another S, interrupt.
  • transceiver unit 108 may be placed in the rear, fixed to an adjustable bracket 170 and suspended below the lower bumper at a desired angle.
  • the bracket 170 as described in greater detail with reference to Figures 18 and 19, may be adjustable so that the direction of the beam transmission may be varied, with a 16° angle, for example, shown in Figure 15.
  • transceiver units may be nested with backup lights behind backup light covers as shown at 172 in Figure 15.
  • radar transceiver units of the present invention may be placed behind the front and/or rear bumper to conceal the unit from view and provide additional protection to the unit.
  • Figure 15 The broken lines of Figure 15 indicate signal transmission lines and connectors leading from the radar transceivers to the visual/audio warning device.
  • Figure 17 illustrates two radar transceivers of the present invention positioned below the bumper and mounted to adjustable brackets 170 of the present invention.
  • Figure 17 is a top view of another vehicle, in this case a tractor trailer, in which two of the radar transceiver units 174, 176 are positioned at the rear of the trailer, with their beams shown in an overlapping relationship.
  • a preferred bracket 170 for retaining the radar transceiver unit 108 of the present invention is shown.
  • Figure 18 is a side view showing a bracket plate 178, a pivot 180 which includes a conventional nut 182 and screw 184 fastener and a transceiver unit retain- ing plate 186.
  • the cone of the transmitting beam is shown as being emitted from the transmitting antenna.
  • a front view of the bracket 170 of the present invention is shown.
  • a high quality, low cost conventional video camera adapted to provide two-dimensional images and real-time video/ audio scenes for image identification, security and video pattern recognition;
  • a smart Doppler radar to calculate the distance between the automobile, truck or other vehicle, and the ob- ject(s) and to provide warning signals, which include an audible alarm beeper, a multi-language warning voice synthesizer, and a green, yellow and red LED for distance display.
  • the warning system 200 is shown schematically in Figure 20 and includes a signal processing unit 202, sensors 204, and display devices 206.
  • the sensors 204 preferably include a video camera 208, a digital camera 210, an infrared sensor 212, a sonar unit 214, a proximity sensor 216 and/or most preferably, a Doppler radar unit 218.
  • the Doppler radar unit 218 is as described above with reference to Figures 1-19.
  • the other sensors used in the present invention are all conventional .
  • the signal processing unit 202 includes a signal processing unit 220 which receives signals from the sensors, and converts any analog signals into digital signals in circuit 222; and makes a rate of motion and distance calculation of objects within range of the sensors for display on one or more of the display devices in circuit and software implementation sche- matical referred to at 224.
  • the processing unit 202 also includes a transmitter/receiver 226 for transmitting signals to and receiving instructions from remote display devices 206.
  • the transceiver 46 is wireless.
  • the data and control signals may be transmitted over conventional sig- nal lines and may use conventional protocols such as presently used to control household appliances with personal computers.
  • the display 206 preferably includes a distance display 228, a video display 230, a multi-language voice synthe- sizer 232, a speaker 234 and a remote display 236 which is preferably a video telephone.
  • Sensors 240-260 may be positioned at various locations along and near the outside of the vehicle, such as, for example, four sensors 240, 242, 246 and 248 near the rear of the vehicle 238 and behind its rear bumper, if the bumper is not metal for the Doppler radar sensors. These sensors are preferably mixed in that a given area of the car should include several types of sensors so that visual as well as range and rate of motion information may be determined concerning an object near the vehicle.
  • the plurality of sensors 250, 252, 254, 256, 258 and 260 may be positioned near the front and front sides of the vehicle in order to obtain visual, distance and rate of motion information regarding objects near the front of the vehicle 238. Signals from the various sensors are then sent to the central processing or signal processing unit 262, processed, and corresponding, processed signals are then sent to display devices.
  • an audio display device 264 is shown near the rear window of the vehicle with speaker 266 and speaker 268 providing audio information concerning objects near the vehicle.
  • audio and/or visual displays 270 and 272 are shown positioned on the dash board of the vehicle.
  • another vehicle 274 is shown schematically and with six sensors of the present invention placed at various locations.
  • one set of sensors 278 is positioned at the mid- die, rear of the vehicle and this combined sensor includes, preferably a Doppler radar transceiver unit as well as a video camera.
  • the sensing unit 278 has an effective zone of coverage toward the rear of the vehicle as represented by area 280 in Figure 22.
  • the left rear of the vehicle in- eludes a sensing unit 282 having Doppler radar and video camera sensing capability to provide an effective zone 284 of coverage.
  • the left front of the vehicle includes a sensing unit 286 having coverage in area 288; the front of the vehicle includes a sensing unit 290 providing coverage for area 292; the right front of the vehicle includes a sensing unit 294 providing coverage in area 296; and the right rear portion of the vehicle includes a sensing unit 298 providing coverage in area 300.
  • each of the sensing units referred to in Figure 22 include a Doppler radar trans- ceiver and video camera, various combinations of the sensors as set forth in Figure 20 may be used.
  • Figure 23 shows an alternate embodiment of the present invention in which sensing units are placed at the left rear, right rear, left front and right front of the vehicle and in an environment in which the vehicle is positioned for parking on a street.
  • the vehicle may be outfitted with four sensing units as referred to, or may have additional sensing units along the side of the vehicle, which sensing units are deactivated in a parking mode of operation.
  • the vehicle 302 includes in its right rear a sensing unit 304 which, preferably includes a video sensor and a Doppler radar transceiver providing coverage of area 306.
  • the left rear of the vehicle 302 includes a second sensing unit 308 which pro- vides coverage of area 310.
  • a vehicle 312, to the rear of vehicle 302 is .within the zone 306 of sensor 304 and zone 310 of sensor unit 308.
  • the left front of the vehicle includes a sensor unit 314 that provides coverage of area 316 and a sensing unit 318 which provides coverage of area 320.
  • another vehicle 322, parked in front of vehicle 302 is within zones 316 and 320.
  • the visual and range information available to the driver of car 302 assists that driver in entering and exiting the parking space next to curb 324 and in front of car 312 and behind car 322.
  • the visual and range information is displayed, for example, on display 326 positioned on the center dash board of the vehicle 302.
  • that display may include a distance display 328, selection displays 330 and 332 indicating to the driver whether the dis- play 326 is providing information concerning the object to the rear of the vehicle or to the front of the vehicle, such as, for example, display 330, when lit, indicating that the range information displayed in display 328 is the range or distance to the vehicle 322 to the front of the car 302, and, when light 332 is lit, the display 328 indicates the distance between vehicle 312 to the rear and vehicle 302.
  • the display 326 may provide for two, simultaneous video displays 334 and 336, with display 334 showing the view from the rear of the car 302, and thus, the front of the car 312, and with display 336 showing the rear of the vehicle 322.
  • various choices of displays may be made, such as providing for an automatic switching or sampling of the display to various of the sensing units, providing for a man- ual selection of the display or displays to be shown.
  • Vehicle 338 is shown with four sensing units positioned at each side of the vehicle. These sensing units may be the only sensing units on the vehicle, or may be in addition to other sensing units placed in the front and rear of the vehicle, as shown and described with respect to other figures.
  • the right front of the vehicle includes a sensing unit 340 which provides coverage of area 342; right rear sensing unit 344 provides coverage of area 346; left rear sensing unit 348 provides coverage of area 350; and left front sensing unit 352 provides coverage of area 354.
  • each sensing unit include a visual sensing device, such as a video camera or digital camera and a range sensing device such as a sonar device or a Doppler radar device.
  • a visual sensing device such as a video camera or digital camera
  • a range sensing device such as a sonar device or a Doppler radar device.
  • the sensing units may be used to provide early warning of a collision, and in addition to providing audio/ visual displays to the driver/passengers of the vehicle 338, may also be used as input to safety devices such as, preferably air bags.
  • the DSP software may be written to provide an activation signal to the air bags of vehicle 338 upon the receipt and verification of signals indicating an impending collision between vehicle 356 and 338.
  • Vehicle 358 is shown with four sensing units and corresponding sensed zones 360 and 362; 364 and 366; 368 and 370; and 372 and 374 respectively.
  • the object of interest is the target 376 which, in this case may be someone approaching the car for purpose of breaking and entering.
  • the system of the present invention can be pre-set to activate a remote video phone 378, preferably digital, in the event a person 376 approaches too close to the vehicle.
  • the video phone 378 may be used from time-to-time to check on the security of the vehicle. For example, if the car is left outside and the occupants are inside having dinner at a restaurant, the video phone may be left on, with a constant video display of the zones 362, 366, 370 and 374 made available to the digital video phone 378.
  • the sensor 360 provides visual and range data regarding the person 376 to the digital processing unit 380.
  • the output of the digital pro- cessing unit 380 is transmitted via antenna 382 to the receiving antenna 384 of the video phone 378.
  • Video information may be shown on display 386 and range information shown on display 388.
  • Key pad 390 may be used to control the system to switch from one display to another, etc.
  • the system may be set up so that if a predetermined combination of size of object, range of object and/or rate of speed of object near the vehicle 358 would exceed some minimum predetermined value, then the system would automatically initiate a call to the video telephone 378 and thereby provide a remote warning of possible breaking and entering, collision or other problem at the vehicle.
  • a building wall 392 having a window 394 and a door 396 is outfitted with a sensing unit 398 which provides coverage in zone 400.
  • the sensing unit 398 preferably includes at least two differ- ent types of sensors, with one providing visual-type information, and one providing range information.
  • building 402 includes a fenced area within fence 404.
  • First sensing unit 406 provides visual and range information in zone 408; sensing unit 410 provides visual and range information for targets or objects within zone 412; and sensing unit 414 provides visual and range information regarding objects within zone 416.
  • various types of display devices may be placed at locations inside of the building, or may be remote-type display devices, such as a video telephone described above with reference to Figure 25.
  • a signal processing unit as described above will be used in a building security system, and the number and loca- tion of sensing units and display units will vary according to each particular building and design choices made by users.
  • video phones as a visual display device
  • television and/or personal computer monitors may also be used.
  • System controls may also be provided through adoption of a conventional signaling protocol, and through a universal controller for a television, the keypad or mouse for a personal computer.
  • the control and data signals may be transmitted wireless, or through hard wires placed in the building.
  • the present systems may also be adapted for use by visu- ally compared persons.
  • the system may be incorporated in a portable unit that could be carried by the user, and when activated, would provide range, speed and size or contour information. It is envisioned that this application would employ conventional video shape recognition technology to assist the user in identifying shapes of objects in zones of interest.

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Abstract

A Doppler radar warning system (30) adapted for use as an automotive safety system including Doppler radar transceiver (31), a digital signal processor (55) for receiving the Doppler radar signals, resolving the signals into a phase difference and determining the distance between a target (42) and the receiving antenna (44), as well as the relative speed of the target (42), and displaying the distance and rate of speed information on a visual (64) and/or audio display (66), including its application in an integrated vehicle and/or building safety warning system including a camera and Doppler radar unit to provide sensing in a surveillance zone of three-dimensional features of objects located in the zone, range information regarding objects located in the surveillance zone, and rate of speed of motion of objects within the surveillance zone.

Description

Description
DOPPLER RADAR WARNING SYSTEM
A portion of the disclosure of this patent document contains material which is subject to copyright and mask work protection. The copyright and mask work owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright and mask work rights whatsoever.
Technical Field
The present invention relates to a Doppler radar that may be incorporated into automotive, residential, business, and other warning systems, and to a fully integrated automotive and/or building safety warning system with three-dimensional features using the combined technologies of real-time video, camera and a smart Doppler radar.
Background Art
The principles of Doppler radar, also known as the Doppler effect, are well known, as explained, for example, in M.I. Skolnik, "Introduction to Radar Systems", McGraw-Hill, 1980, Chapter 3, CW and Frequency-Modulated Radar. Warning systems, including vehicular warning systems which implement Doppler radar, have been described in U.S. Patent Nos. 3,863,253 ("'253") and 5,087,918 ('"918").
The '253 system is an analog system which converts the Doppler signals corresponding to two signals transmitted from the vehicle and returned as echo signals from the object into two rectangular signals, an exclusive OR gate which receives the two rectangular signals for producing pulses each appearing at a time when either of the rectangular signals appear, and an averaging circuit to produce a signal representative of the distance between the vehicle and the object.
The '918 system provides object range resolution, detection of both stationary and moving objects, and resolution of multiple objects, through use of six radio frequency heads that transmit and receive radar signals of both frequency- modulated continuous wave type and two-frequency Doppler type signals. In the '918 system, detection of an object is signaled by a visual indicator and an audible indicator.
Disclosure of Invention It is an object of the present invention to provide a safety warning system which includes digital signal processing hardware made with inexpensive, conventional components and computer program-implemented software for processing the signals generated by the system. Doppler radar to detect objects nearby, and the object's distance and relative speed.
It is a further object of the present invention to provide a safety warning system which combines two distinct technologies: a high quality, low cost video camera and a smart Doppler radar for the purpose of detecting objects near the vehicle, building or other area; determining the distance and relative speed of the object in relation to the vehicle, building or other area; and providing visual and audio information concerning the object. /// Brief Description Of The Drawings
Other objects and advantages of the invention will become apparent from the foregoing detailed description taken in connection with the accompanying drawings, in which: Figure 1 is a block drawing showing the components of a preferred embodiment of the Doppler radar system of the present invention.
Figure 2 is a diagram showing the phase relation of the signals used in the Doppler radar of Figure 1. Figure 3 is a block diagram showing the phase comparator of Figure 1.
Figure 4 is a block diagram showing the digital filter of the digital signal processor of Figure 1.
Figure 5A is a schematic circuit diagram of the trans- mitter/receiver module of the Figure 1 embodiment.
Figure 5B is a reproduction of the mask work of the circuit the transmitter/receiver module of the Figure 1 embodiment.
Figure 6 is a reproduction of the mask work of the trans- mitting and receiving antenna of the Figure 1 embodiment.
Figure 7 is a schematic diagram showing the relationship of the radar beams and reflectors used in the Figure 1 embodiment system.
Figure 8 is a block diagram showing the relationship of a target-to-zones in relation to the Figure 1 embodiment.
Figure 9 is a schematic diagram showing a cone of coverage, together with reference coordinates for the radar beams of the Figure 1 embodiment. Figure 10 is a schematic diagram showing the Figure 9 cone and including coordinates for objects in three zones within the cone.
Figure 11 is a schematic diagram showing two transmitter/ receiver units together with a digital signal processing and display unit of the Figure 1 embodiment.
Figure 12 is an exploded perspective view of a transmitter/receiver unit of Figure 11.
Figure 13 is an exploded perspective view of the digital signal processing and display unit of the Figure 1 embodiment. Figure 14 is an exploded, rear perspective view of the Figure 13 unit.
Figure 15 is a schematic view of a vehicle illustrating the positioning of a transmitter/receiver unit of Figure 12 for the Figure 1 embodiment.
Figure 16 is a rear view of Figure 15 vehicle, showing two transmitter/receiver units.
Figure 17 is a top schematic view showing two transmitter/receiver units positioned at the rear of a truck. Figure 18 is a side, cross-sectional view of a bracket used to retain a transmitter/receiver unit of Figure 12.
Figure 19 is a front view of the Figure 18 bracket and transmitter/receiver unit.
Figure 20 is a schematic drawing showing the components of an alternate preferred embodiment of the present system including displays, a processor and sensors.
Figure 21 is a top schematic view of a vehicle showing the position of transceivers and display devices for another preferred embodiment of the present invention. Figure 22 is a schematic view of a vehicle showing the positioning of transceivers of the present invention in another alternate embodiment.
Figure 23 is a schematic view of a vehicle with trans- ceivers of the present invention placed in alternate positions in another alternate embodiment, and showing the vehicle in a parking environment and with an alternate display device.
Figure 24 is a schematic diagram of a vehicle showing transceivers placed in the side of the vehicle and in an envi- ronment where another vehicle is approaching the first vehicle from the side.
Figure 25 is a schematic diagram showing the use of the present invention as a security warning device wherein signals from the approaching target are transmitted to a remote video telephone.
Figure 26 illustrates the present invention as placed on a building above a door way.
Figure 27 illustrates the present invention in an embodiment in which three transceivers of the present invention are positioned at various locations on a building to provide a wide area surveillance capability.
Figure 28 is a flow diagram of the main routine for the computer implemented software for the Figure 1 embodiment.
Figures 29A-29D are flow diagrams of sub-routines of the main routine for the computer implemented software for the Figure 1 embodiment.
Figure 30 is a schematic diagram showing the relationship of the Doppler-shifted signals in a manner to facilitate understanding of the conversions from frequency to period for the Doppler-shifted signals, of the relationship of the terminology used in the software routine in comparison to the other portions of the description of the invention and the manner in which forward and reverse directions are determined.
Best Mode for Carrying Out the Invention
In the following description, like reference numerals will be used to refer to like or corresponding elements in the different figures of the drawings for the purpose of illustration.
The preferred embodiment described herein includes a computer software implementation based on an 8-bit microprocessor, such as for example a Z86E31, manufactured by Zilog. It is recognized that the principles of the present invention may be used with other processors. One of the advantages achieved by the present invention is the capability of providing a Doppler radar system which is implemented with relatively simple, inexpensive components, such as, for example, an 8-bit microprocessor. Of special importance are the feature which ex- tracts the useful information from the Doppler shifted analog signals by converting the zero crossing times into digital signals which can then be relatively quickly, accurately and inexpensively processes the Doppler-shifted signals representative of phase angle and unfiltered, approximate range infor- mation; and the discovery of the filtering circuit which uses the concept of division by an integer and feedback of the divided signal to quickly, simply and inexpensively reduce unwanted noise and false alarms. As shown in the drawings for purposes of illustration, and with reference to Figures 1-14 and 28-30, a first preferred embodiment of the Doppler radar transmission, receiving and signal processing components of the present system will be described. These components provide a low cost, accurate range-finding capability for warning systems that may be used in the automotive, trucking, and other vehicular fields, as well as in building and other security fields of application. Figure 1 provides a block diagram illustration of a Dop- pier radar warning system of the present invention. Doppler radar unit or system 30 includes a transmitter 32 and a receiver 34 which together are referred to as the transceiver. The transceiver components are concluded in a module 31. The preferred circuit which is illustrated in Figures 5A and 5B, as will be described in greater detail. The transmitter 32 includes a voltage-controlled oscillator ("VCO") 36 and a frequency-shifted keying modulator ("FSK") 38. The VCO 36 is a radio-frequency ("RF") oscillator whose oscillating frequency is determined by a controlled voltage. VCOs of the type used in the present invention are commercially available and the oscillating frequency as used in the present invention is chosen to be within the 5.8 GHz ISM frequency band. The ISM frequency band is the U.S. government Federal Communication Commission allocated frequency band for industrial, sci- entific and medical applications and for which no license is required. The FSK modulator 38 is a conventional square wave generator whose output voltage wave form is sent through line 39 and used to control the VCO to produce two distinct frequencies at F0 ± ΔF, in a conventional manner. FSK modulators are commercially available and, for the purpose of the present invention the preferred range of frequencies which may be used for F0 are within the range of 5.725 GHz to 5.850 GHz. Also, within the scope of the present invention, the preferred range of change of frequencies, ΔF, is from 1 MHz to 2 MHz. The FSK modulator 38 simultaneously provides a signal through line 37 to control the demultiplexer ("DE-MUX") circuit 54 in the receiver 34 to recover two Doppler echo signals reflected from the moving target or object 42. The trans- mitter 32 also includes a transmitter antenna 40 ("Tx") which receives the VCO signal output through line 41 and radiates the RF energy toward the object 42.
The receiver 34 includes a receiver antenna ("Rx") 44 which receives the reflected RF energy from the object 42. This reflected energy, the echo, is at a different apparent frequency due to the Doppler effect, as is well known. The analog signal from the Rx antenna 44 is then sent through line 43 to low noise amplifier ("LNA") 46 which amplifies the received RF signal by a factor of approximately 10. The am- plified RF signal is then sent via line 45 to a mixer 48, which produces an intermediate frequency ("IF") analog signal from the product of the transmitted and received signals. The mixer 48 is a circuit which converts high frequency energy into a lower, intermediate frequency energy in a conventional fashion, by subtracting the frequency of the echo signal from the frequency of the transmitted signal.
The analog IF signal, which is representative of the Doppler shift, or effect, is then sent via line 47 to the IF amplifier 52 which amplifies the IF signal by a factor of approximately 1,000. The IF amplifier 52 is a conventional analog amplifier. The amplified IF signal is then sent via line 53 to the demultiplexer circuit 54, which separates the two mixed, amplified Doppler shifted signals reflected from the object. These two Doppler signals are referred to as signal S,, which is the Doppler shifted signal which had been transmitted at F0 + ΔF. The second signal, referred to as S2, is the Doppler shifted signal which had been transmitted at frequency F0 - ΔF. The separated analog signals, S, and S2 are sent via lines 56 and 58, respectively, to phase comparator 60. Phase comparator 60 converts these analog signals to digital signals and determines the phase difference, referred to as Δθ, between the two Doppler signals S! and S2. The phase difference, Δθ, is represented by a digital signal which is then sent via line 61 from the phase comparator 60 to the digital signal processor ("DSP") 62.
The DSP 62, and its application software calculate the object distance, i.e.. range or "R" from the object to the antenna by using the phase difference Δθ, and the known rela- tionship that the distance "R" is directly proportional to the phase difference. The DSP software is represented schematically at 55 in Figure 1. The DSP also includes a digital filter 63 which filters out unwanted noise and minimizes the number of false alarms. Digital signals representing the calcu- lated distance R are then sent to displays; for example, a light display 64 and an audio display such as a beeper 66. Preferably, the number of lights energized in the display is in inverse proportion to the distance R. The beeper has a sounding frequency which is inversely proportional to the dis- tance R. Other displays, of course, may be used, such as numerical displays of distance, voice statements of distances, etc.
Referring to Figure 2, the relationship between the two Doppler shifted signals S, and S2, and how useful information regarding phase angle is extracted and converted to digital form is shown. The vertical axis represents an analog signal amplitude at ± voltages, with the horizontal axis representing time. The signal S, is shown crossing the 0-voltage line at T, and T3 as signal S, increases in voltage from 0 volt to its maximum voltage and then decreases again to 0 volt. Similarly, the signal S2 is at 0-voltage, the "signal 0" at T2 which is some time later than the T, at which the signal S, has its signal 0. This relationship is preferably implemented in the application software, flow diagrams of which are illustrated in Figures 28 and 29 -D.
Figure 3 is a block diagram of the phase comparator 60, which is preferably implemented with the digital signal processor application software, and which includes two conven- tional signal 0 crossing detectors that initiate interrupt requests to the digital processor software routine at 0-crossing T, , T2, T3, etc., as shown in Figure 2. The zero crossing detectors are typically included in microprocessor chips of the size for which this invention is intended. The analog signals are thereby converted to digital signals, and further processed by the DSP software. As shown in Figure 3, the signal S! is monitored by the 0 crossing detector 72, and when signal S, crosses the 0-voltage condition, interrupt requests are sent to the digital processor for determination of the 0-crossing times at T, and T3, as shown at 76," for signal S,. Similarly, 0-crossing detector 74 monitors signal S2 and provides an interrupt request to the digital processor for reading the 0- crossing T2 of signal S2. The 0-crossing T,, T2, and T3 are then used to calculate the phase difference, Δθ, as shown at 80, in Figure 3, and using the formula Δθ = (T2 - Tj)/(T3 - T,) .
As is well known, the phase difference Δθ is directly proportional to the range of an object from the transmitter antenna 40. The distance R is then obtained by the use of the formula R = K, Δθ, where K is a constant that is empirically determined. From the calculation performed by the software routine, and as schematically referred to at 80, a digital signal 82, representative of the distance R between the target and the transmitter antenna is then sent to the digital fil- tering circuit 63.
As is also well known, the relative speed of the object is proportioned to the difference between T3 and T,, and may be represented by the formula Δ Speed = K2 / (T3 - T,) , where K2 is a constant that is empirically determined. The DSP also de- termines speed information in accordance with this relationship.
With reference to Figure 4, the digital filtering feature of the present invention is shown schematically at 63. This filtering function is preferably implemented in the applica- tion software and functions to reduce noise and minimize false alarms. Input signal 82 which is representative of the range, R. The digital filter 63 may be referred to as a feedback loop, and with the flow chart for the preferred embodiment being shown in Figure 29A-D. The filter 63 has the raw, unfiltered signal 82, i.e., S(82) as its input. The processing of the input signal S(82) , as shown in Figure 4 is as follows: S(82) has subtracted from it, at subtraction node 84, the signal in line 94, S(94) , to become the signal in line 85, i.e., S(85). S(85) is then divided by N at 86. N is an integer, found to be in a useful range of from 1 to 10. The preferred values of N are 4, 5, 6, 7 and 8. The value 6 is the most preferred value for N in regard to the first embodiment. It has been discovered that N values of 1, 2 or 3 tend to yield an insufficient reduction in noise and too many false alarms. N values of 8 , 9 and 10 tend to yield more noise reduction, but the response time is too slow. Also, it is emphasized that the particular choice for an N value depends on the particular application for which the warning system is to be used. The preferred value of 6 has been found to be the best choice for the vehicular warning system of the first embodiment of the present invention.
The divided signal, S(87) then has added to it the signal S(92) at node 88 to yield the signal R' , at 96, which more ac- curately represents the final estimated range. The R' signal is also returned to the feedback loop at 90, and through line 92 is added at node 88 to S(87) and through line 94 is subtracted from S(82) at 84. Once the unfiltered signal R has been processed to minimize false alarms and reduce noise, the signal R1 shown at 96, is output and is a representation of the final, estimated distance or R from the object to the transmitter antenna. This signal may be then sent to conventional displays using conventional techniques. Referring to the Figure 5A schematic circuit diagram, the circuit for transmitter-receiver module 31 will be described. The module 31 includes the circuitry shown in Figure 1 and described above. VCO 31 is represented by transistor 356 which is an FET transistor, preferably Hewlett Packard Part No. ATF- 13786. The LNA 46 is shown at 328 and is an integrated circuit with Hewlett Packard Part No. MG886563. The mixer 48 is shown at 335 in Figure 5 and includes diodes 336 and 338, with Hewlett Packard Part Nos. HSMS2852 for both diodes which are typically commercially available as a single package which contains the two diodes. The VCO 36 includes transistor 356 and Varactor diode 360. The diode 360 is, preferably, Siemens Part No. BBY5203W and the transistor 356 is preferably a Hewlett Packard Part No. ATF-13786. These above-mentioned components form the active components in the circuit, with the remaining components being typical, passive components including various capacitors and resistors and a microwave transmission line shown at components 342, 340, 356, 344, 352, 374, 372. This reference again to Figures 1 and 5, the circuit will be explained. The FSK modulator 38 generates a 50 KHz square wave, as shown at 304 in Figure 5A. The signal then is transmitted to and through resister 390 which is a 50K OHM resistor and then to the variable resistor 392 which is a 5K OHM vari- able resistor. Next, the signal proceeds through a capacitor 394 which is preferably a .IMF (micro Farad). The signal then is transmitted to a node and is split, part of which goes to ground through resistor 376 which is a 100K OHM resistor. The signal also goes to the next branch downward as shown in Figure 5A through resistor 375 which is a 10K OHM resistor and goes into the Varactor diode 360, which functions in a conventional fashion to modulate the frequency. Downstream of the capacitor the signal then goes to ground through resistor 358 which is a 10K OHM resistor and into the gate of transistor 356. The source of transistor 356 then is connected to ground via resistor 354 which is a 22 OHM resistor. The drain side of transistor 356 then connects to capacitor 362 which is a 7 Pico Farad capacitor and makes a complete circle back to the Varactor diode 360. The drain of transistor 356 is also the power output, the major portion of the power output passing through capacitor 364 which is a 7 Pico Farad capacitor and then through the power divider shown at 367, and, as represented in the Region 1 on the Figure 5 B transmitter/ receiver module PCB design. One portion of the power is then sent to the transmitting antenna connecting point 370 as shown in Figures 5A and 5B and then to antenna 40 as shown in Figure 1. The line 366 in Figure 5A represents a tuning stub. The remaining power then is sent through the opposite line of the branch and into the mixer 335 in Figure 5A, and shown at 48 in Figure 1.
Referring to Figure 5A, at the lower left hand corner, connection point 324 to the receiving antenna 44 connects adjacent the antenna 44 as shown in Figure 1. The Doppler shifted signal which is returned from the target or object 42 then is transmitted down the line and through capacitor 332 which is a 33 Pico Farad capacitor. The signal then enters the LNA 328 as shown in Figure 5A, and referred to as 46 in Figure 1. The signal output from the low noise amplifier 328 is then passed through capacitor 330 which is a 10 Pico Farad capacitor and from there through resistor 334 which is preferably a 10 OHM resistor and from there into the mixer 335 as shown in Figure 5A. Line 340 represents a tuning stub. The output from the low noise amplifier 328 also is sent to a matching network 325 via the line and resistor 326, which is preferably a 68 OHM resistor. The matching circuit includes the transmission line illustrated schematically at 342 and shown in detail in the PCB design of Figure 5B. Of i por- tance, it is noted that one branch of the transmission line 342 includes a conventional microstrip line which is 20 mil. wide and 250 mil. long. The matching network also includes a 1 Pico Farad capacitor 322 which is connected to ground and a second 0.01 MF (micro Farad) capacitor 320 which is also connected to ground. At .306 a +5 volt DC voltage is applied to voltage divider circuit which includes resistor 384, a 10K OHM resistor, resistor 388 which is a 10K resistor, resistor 386 which is a 10K resistor and variable resistor 382 which is a 100K OHM variable resistor, and then through resistor 380 which is a 1 MEG OHM resistor and then goes into transistor 378 which is commonly available transistor, Part No. BCW60D. One output of the transistor 378 goes to line 379 and it is here where the frequency F0 is set up. Referring to line 381, downstream from the capacitor 394, the ΔF is determined, thus at transistor 356 the frequency F + or - ΔF is alternatingly produced. In summary, this part of the circuit uses a DC voltage to produce the desired frequency F0 + or - ΔF. In the preferred embodiment, reference numeral 302, 308, 310 and 314 are connections to ground in accordance with standard microwave design practice. The connections points 316 and 318 are not connected in the preferred embodiment. With reference to the Figure 5B transmitter-receiver module printed circuit board design, it is noted that this is an enlargement of the actual mask for the transmitter-receiver module 31 as shown in Figure 1. The exact proportions and dimensions shown therein embody the preferred microwave design for the embodiment for the Figure 1 embodiment shown at reference numeral 31 in Figure 1.
Referring to Figure 6, an enlarged copy of mask for the transmitting antenna 40 and receiving antenna 44 are shown together with dimensions. As shown, each antenna is of a trian- gular shape. The antenna substrate material is FR4 , as commonly referred to in the field of microwave technology. The preferred substrate thickness is 32 mils.
Referring to Figure 7, a top view, schematic representation of the antenna and reflectors with variable beam width capability will be described. Transmitting antenna 40, connected to the system 30, has a first plane reflector 98 and a second plane reflector 100, with included angle Φ therebetween. Each of the reflectors 98 and 100 may be rotated about a vertical axis 102, 103 to form an adjustable radial wave guide 104. The included angle Φ may be adjusted to vary the beam width of beam A. The orientation of the radial wave guide 104 can be varied to steer the beam. As shown in Figure 7, which is a top view, increasing Φ would widen beam A. Movement of the entire wave guide 104 to the left or right would move beam A and beam B to the left or right.
Referring to Figure 8 , a block diagram of the receiving antenna, target or object and warning device of the present invention will be described. As may be seen, a series of zones has been defined as representing a range of distances from the antenna. The DSP can be programmed to detect objects located in a predetermined zone. For example, the object in zone 2 would be detected, and all other zones would be ig- nored. Multi-zones, such as zones 2 and 5 (not shown) , or zones 1, 3 and 6 (not shown) could be assigned for detection, and other zones ignored. The antenna receives a reflected signal from the target 42, sends it to the radar transceiver 31 via antenna 44, then to the digital signal processor 62, and ultimately to the visual/audio warning devices 64, 66.
Figures 9 and 10 illustrate the concept of a cone within which objects may be identified and their ranges from the antenna may be determined through use of a coordinate system. Referring to Figure 9, a truncated cone 106 is shown as ex- tending outward from its narrow end, which terminates at the transmitting/receiving antenna unit 108 of the warning system, and outward to some predetermined distance. Within the truncated cone an X, Y, Z coordinate system is established, with the antenna unit being the center of the coordinate system, the X direction being left-to-right from the center point of the antenna and facing in the direction of the transmitted beam. The Y direction is vertical, and the +Z direction is the horizontal direction of the transmission. With references to Figures 10, it then may be seen that zone 1 may be defined by regions inside the cone 106 from the transmitter/receiver module 108, i.e.. Z = 0 out to the value of Z = a predetermined value, and with the X and Y values de- fining a series of circles or ellipsis within the cone. Similarly, zone 2 would be that region within the cone between Z, and Z2; and zone 3 would be that region inside of the cone between Z value Z2 and Z3.
In the preferred embodiment of the present invention, the Doppler radar warning system is incorporated into a vehicular safety warning system having two transmitters and receivers connected to a single digital signal processor and display unit. Referring to Figure 11, the first transceiver unit 108 is shown with mounting brackets 110, 112, mounting plate 114 and radar transmitting antenna 40 and radar receiving antenna 44 shown respectively. The preferred antenna is made of a metallic patch and is of a triangular configuration measuring about 0.6 inch at each side as shown in Figure 6 and further described above. Other materials, sizes and shapes, of course, may be used, or will be appreciated by those skilled in this field, and are considered to be equivalent. Signal cord 116 is shown leading from the transceiver unit 108. The transceiver unit 108 may be combined with other transceiver units as input, for example, unit 118 which is identical to unit 108. Signal input lines 116 and 120 are shown as receiving signals from either a signal transceiver unit 108, 118, respectively, or multiple transceiver units via lines 122, 124. The signals are input to the visual/audio warning device, as shown at 126. It is envisioned that transceiver units such as shown in Figure 11 would be placed, for example, on the left and right areas of the front and/or back and/or sides of a vehicle such as a car, truck or other vehicle.
Referring to Figure 12, an exploded, perspective view of the radar transceiver unit 108 is shown. The unit includes a housing 128, mounting brackets, a back plate 132, an antenna holding substrate 134, upon which the transceiver printed circuit board circuit 31 is held, a receiving antenna 44, a transmitting antenna 40, antenna holding brackets 136, 138 and signal processing cord 116. The housing also includes a front cover 140 which may be sized and shaped to form any convenient shape, such as to simulate a head lamp or some other part of the vehicle to camouflage its identity as a radar transceiver. Preferably the transceiver housing is made of a durable plas- tic and is of a type for which the radar signals may pass easily therethrough. Most preferred, however, the transceiver units are positioned behind nonmetallic bumper (s) of the vehicle. In this way they are highly protected and camouflaged, but are fully functional. With reference to Figures 13 and 14, the visual/audio warning display component 126 of the present invention adapted as an automotive warning system will be described. The display 126 includes a main housing 142 portion and a top housing 144 portion. A front plate 146 provides for a plurality of light emitting diodes and a speaker 164 for display of the visual and audio signals from the digital signal processor. An audio volume control is shown at 165. Of a total of ten light emitting diodes (LEDs) , four LEDs 148, 150, 152 and 154 are shown with corresponding light paths indicated at 156, 158, 160 and 162. Pin connections 166, 168 are located at the rear of the unit to receive signal wires 116, 120.
Referring to Figures 28, 29A-D and 30, the preferred software application for the present invention will be de- scribed. This application is capable to determine distances in the case when the object is moving toward the transceiver, i.e.. the forward, or advancing direction, as well as when the object is moving away from the transceiver, i.e.. the reverse or retracting direction. With respect to the signals S, and S2 as shown in Figure 2, it is noted that this relationship occurs when the object is moving away from the transceiver. With reference to Figure 30, a schematic representation of the signals along the time axis in the case when the object and the transceiver are moving toward each other is shown. Also, Figure 30 includes a square wave representation of the signals with the designators "H" and "L" referring to the distance between S, old and S2 old and the distance H + L is represented by S2 new - S2 old. As is also shown in Figure 30, the distance ratio then may be expressed as H ÷ (H + L) . With refer- ence to the preferred software routine, then, only one formula need be used, which is shown below as follows:
H/(H + L) = (S, old Time - S2 old Time) ÷ (S2 new Time - S2 old Time) . In the reverse situation, that is, when the target and the transceiver are leaving each other, the relationship is expressed by simply swapping H and L to yield the ratio L ÷ (L + H) and the distance ratio then may be expressed as L/(L + H) . Referring first to the Figure 28, software routine, which is implemented on a Z86E31 IC chip, the routine begins at step 502 with power being supplied to the chip. Then, at step 504, the chip is initialized with the variable RDY set equal to 0. Next, at step 506, the main program waits for an interrupt, which interrupt comes in when the S, signal crosses the 0-volt condition. Referring to decision point 508, in the event the S, interrupt comes in, then the RDY register is set equal to 1 at step 510. Next, another decision point 512 is reached where the program checks to determine whether the RDY register is set equal to 1. If no, then the program returns to the wait for interrupt condition at 506. If the RDY register equals 1, then the main program continues to step 514 where the RDY register is reset to 0, so that when either the program is restarted or is returned to step 506, the RDY register is set at 0. After clearing the RDY register to 0, next the program performs the calculation which determines the ratio used in the distance calculation at step 516 and, as will be explained later in greater detail in regard to the calculation subroutine.
Once the calculation ratio in step 516 has been determined to yield a distance ratio, that distance ratio is then multiplied by an application specific and empirically determined scaling factor in step 518. Once the scaling factor has been applied to the distance ratio in step 518, then another calculation in step 520 is performed to more closely approximate the true distance in the condition when the target and object are moving together and to differentiate between that condition and the condition when the target and object are moving apart. For example, in the preferred embodiment the distance value resulting from step 518 in the forward, that is, the condition when the target and transceiver are moving towards each other, is a distance from which the number 1 is subtracted. It has been found that in the vehicular system of the first embodiment, the value 1 yields best results and is therefore preferred. For other applications a different number might be used instead of 1. In the case where the object and the transceiver are moving away from each other, the dis- tance figure resulting from step 518 is left unchanged.
The value calculated in step 520 is then sent to the filter subroutine, represented as step 522, in Figure 28. The filter subroutine, in general, provides a loop or feedback calculation in which noise and false alarms are minimized. In the preferred embodiment as shown in Figure 28, the filtered distance is represented by a variable named DF. The final value of the DF variable is stored in a register which is set equal to a DF initial value plus the value of the distance from step 520 minus the initial DF value ÷ 6. In this calcu- lation and for purposes of the best mode of practicing the invention in its embodiment 1 , it has been found that a value of 7.0 for the DF initial value is most preferred, and that the most preferred number in the denominator is 6. It is noted that the number 6 in the denominator in step 522 corresponds to the value N as set forth at 86 in Figure 4. As described above, this value is an integer, and is within the range of 1- 10. Specific applications will use different values for N, with the particular value chosen being an optimization for the particular application. Once the filtering calculation is performed in step 522, the DF final is sent to decision point 524 and checked to determine whether the DF value final is less than 0. If the value is less than 0, the main program returns to wait for interrupt 506, negative numbers having no significance in the present application. If the DF value final is 0 or a positive number, then the decision point 524 result is no and the signal energizes beeper 526 and the bar code visual display 528 and returns the main program to the wait for interrupt step 506. With respect to 522, the initial value of DF is set to 7 for the first calculation or first iteration through the main loop. In each subsequent iteration of the loop, while energized, the initial DF for each subsequent loop is set to be equal to the final DF of the previous iteration. For example, considering the case when the system is turned on and DF initial is set to 7.0 and assuming as a result of the first iteration through the main loop, the final DF is + 6.0. In that case, at step 524 the decision would be no, the beeper and bar code would be energized and the main loop would return to step 506 for the next S, interrupt. When the next S, interrupt came in and the program proceeded through steps 508 through 520, the next distance calculation entering step 522 would be filtered with the initial DF being 6.0 rather than 7.0 as in the previous iteration. In similar fashion each succeeding iteration of the main loop would then use new DFs.
Now referring to Figure 29A, the subroutine 516 will be described in regard to the calculation of the ratio as expressed in step 516 of Fi ure 28. As shown, main loop 500 provides information to decision point 530 as shown. If the data is not ready, then the program returns to the main loop. If data is ready, then the decision is yes and the subroutine proceeds to step 532 where time, expressed as H + L is inverted and thereby converted to frequency. Also, in step 532, frequencies of less than 0.7 Hz are rejected as having no meaning for the present application. For signals that are not rejected at 532, they then proceed to step 534. Step 534 is referred to as a range gate. The term range gate means that a distance or range between the transceiver and a proposed target or beginning of a zone is predetermined and set so that the system will perform calculations and the filtering functions only on reflected signals within the set range. For the preferred embodiment of the present application, the range has been set at 8 feet, meaning that signals which have been processed through step 532 but indicate a distance of greater than 8 feet will be rejected, whereas signals that have passed through step 532 and indicate a distance of 8 feet or less will be further processed. It has been found that the range of 8.0 ' is most preferred for the present ap- plication, although it will be understood that different ranges may be chosen for different applications, and that a plurality of range gates may be used so that objects in different zones may be determined while objects in other zones may be ignored. In the event that the range gate option is not exercised, the decision is no in step 538 and the program then skips over step 536. In the event the decision at step 534 is yes, indicating that the object is 8' or closer to the transceiver, the program then goes to step 536 where signals greater than 300 Hz are also rejected as of no usefulness in the present application. As may be appreciated, steps 534, 536 and 538 are useful by discarding unusable signals that would otherwise slow down and clutter up the program.
Referring to step 540, a reverse determination is made. In the event the object is moving away from the transceiver then the decision at point 540 is yes and the program goes to step 542 where the variable is converted to be a ratio repre- sentative of L ÷ (H + L) . This ratio is rejected for cases in which this value is greater than 0.25. The value of 0.25 has been determined to be most preferred for the present application, although it is recognized that other values may be chosen for other applications. In the event the decision at step 540 is no, indicating that the object is moving closer to the transceiver, then the variable is converted to be representative of H ÷ (H + L) and in cases where this signal is greater than 0.25, all such values are also rejected. The calculations in steps 542 and 544 are merely calculations of ratios. In the event where the ratio in step 542 is greater than 0.25 or where the ratio is greater than 0.25 in step 544, the signal is rejected as having no known useful purpose in the present application.
Next, when the ratios are equal to or greater than 0.5, the signal is sent to dynamic rescaling step 546 in order to provide more useful and accurate information from the data collected. Specifically, in step 544, the value for H is 2 bytes in size whereas in step 548 the value for H has been converted to a 1 byte value, and the technique of converting from the 2 byte to the 1 byte is a conventional dynamic re- scaling technique which takes place in step 546. The rescaled ratio is set forth and expressed in step 548, with the example being the case of a forward direction of motion, i.e.. when the object and the transceiver are moving together.
After step 548, the signal is then sent to step 550 which is a round off step and decision point. In the event the decimal part of the ratio of signal 548 is equal to or greater than .5, then the value is sent to round off step 552 and rounded off to the next highest integer. In the event that the decimal part of the signal 548 is less than .5, then the decimal part of the ratio is discarded and only the integer remains.
Now referring to Figure 29B, which is a continuation of Figure 29A, the rounded integer from steps 550 and 552 are now sent to decision point 554 for again, a determination of whether the value expresses a reverse direction or not. In the event the ratio expresses a reverse direction, then the distance is expressed as the ratio x 85% in step 556. It is noted that the value 85% has been determined to be the best value for the present application of embodiment 1, although other values could be used in other applications. Similarly, if it is determined that the decision in box 554 is no, indicating a forward direction, that is the object and the transceiver are coming closer together, the ratio is multiplied by 65% to yield the distance calculation in step 558. Again, the value 65% has been empirically determined to be the best mode for the present application and this number could be varied in other applications. The result of step 558 then is sent to decision box 560 and steps 562 and 564 where again, the forward distance is determined to be the distance value from step 558 minus 1 in step 564 and the distance value in the case of a reverse di- rection is the distance value expressed in step 558 minus 0, which is another expression or a repeat of step 520 as explained above with respect to the main program 500. Next, at step 566, a determination is made concerning whether the distance equals 0, and if the answer is no, then the program skips around step 568. If in decision box 566 the distance is 0, then the subroutine proceeds to step 568 where a conventional determination is made regarding whether the 0 signal is the result of noise. If the answer is yes, then the program returns to the main loop 500 and if the answer is no, the pro- gram continues to the part of the subroutine shown at Figure 29C.
Referring to Figure 29C, the program proceeds from step 568 to step 570 where the routine checks to see whether this is the first time after power on. If the answer is yes, then the program proceeds to step 572 where the variable DF is set equal to 7 , as explained previously. In the event the decision at step 570 is no, indicating that this was not the first time after the power was on, the program then skips to decision point 574 decision point and at this point the pro- gram checks to determine the value of the distance calculated in steps 564 and 566 minus the initial value DF, which has been set initially to 0. If the distance minus the variable DF is less than 0, then the answer at 574 is yes and the program proceeds to step 576. If the answer is no at 574 indi- eating that distance minus DF is equal to or greater than 0, then the program proceeds to step 580.
In step 576, the same calculation is performed except that the comparison is made to -1. If the value of distance minus DF is less than -1, then the answer is yes and the program proceeds to step 578. If the answer is no, the program then proceeds to step 582. In the case where step 578 is reached, then the variable is set to -1 and the program proceeds to step 582. Referring to decision box 580, the same calculation as set forth in step 574 is performed; however, the calculation is compared to the value +1. If the value is greater than +1 then the program proceeds to step 579 and if the answer is no, the program proceeds to step 582. In step 579, if the dis- tance minus DF is greater than +1, then the variable is set to +1 and the program proceeds to step 582.
In step 582, a new variable, referred to as DFR, is set equal to the DFR initial plus (distance minus DF) . In this step the final DFR is contained in a register and it is con- stantly updated as more iterations of the program take place. Following each step 582 the program then proceeds to step 584 as shown in Figure 29D. In step 584, the final value of DFR is compared to 0. If DFR is not greater than 0, then the program proceeds to step 594. If the value of DFR is less than 0, then the program proceeds to step 586.
In step 594, the value of DFR is compared to 6 and if the value is greater than 6 the program proceeds to step 596 where the variable DF is set equal to DF + 1. If the answer is no in step 594, then the program proceeds to decision point 600. Returning to decision point 586, the variable DFR is compared to the value -6 as shown, and if the answer is no, the program proceeds to step 600. In the event the variable DFR is less than -6, then the program proceeds to step 590 where the variable DF is set equal to DF - 1 and the program proceeds to step 592 where the variable DFR is cleared, by setting it equal to 0, and the program then proceeds to step 600. In decision point 600 the variable DF is compared to the value 0 and if the answer is yes, indicating that the vari- able DF is less than 0 the program returns to the main loop. If DF is equal to or greater than 0, then the program proceeds to the beeper 602 and the bar code 604 and the value of DF is displayed in an appropriate fashion such as volume or frequency of beeps and/or number or sequencing of lights, and is re- turned to the main loop 500 as shown in Figure 28 in the lower right corner where beeper step 526, bar code 528 are also shown, but with different reference numerals. In this case return to the main loop means that the program returns to step 506 waiting for another S, interrupt. Referring to Figures 15-16, various locations for placement of the radar transceiver unit 108 of the present invention are illustrated. For example, transceiver unit 108 may be placed in the rear, fixed to an adjustable bracket 170 and suspended below the lower bumper at a desired angle. The bracket 170, as described in greater detail with reference to Figures 18 and 19, may be adjustable so that the direction of the beam transmission may be varied, with a 16° angle, for example, shown in Figure 15. Alternatively, or additionally, transceiver units may be nested with backup lights behind backup light covers as shown at 172 in Figure 15. Alternatively, and most preferably, radar transceiver units of the present invention may be placed behind the front and/or rear bumper to conceal the unit from view and provide additional protection to the unit. The broken lines of Figure 15 indicate signal transmission lines and connectors leading from the radar transceivers to the visual/audio warning device. Similarly, Figure 17 illustrates two radar transceivers of the present invention positioned below the bumper and mounted to adjustable brackets 170 of the present invention.
Figure 17, is a top view of another vehicle, in this case a tractor trailer, in which two of the radar transceiver units 174, 176 are positioned at the rear of the trailer, with their beams shown in an overlapping relationship. With reference to Figures 18-19, a preferred bracket 170 for retaining the radar transceiver unit 108 of the present invention is shown. Figure 18 is a side view showing a bracket plate 178, a pivot 180 which includes a conventional nut 182 and screw 184 fastener and a transceiver unit retain- ing plate 186. As shown in Figure 18, the cone of the transmitting beam is shown as being emitted from the transmitting antenna. Referring to Figure 19, a front view of the bracket 170 of the present invention is shown.
An application of the Doppler radar warning system in automotive safety warning system will now be described as an alternate preferred embodiment of the present invention. This embodiment combines two distinct technologies as follows:
(1) a high quality, low cost conventional video camera adapted to provide two-dimensional images and real-time video/ audio scenes for image identification, security and video pattern recognition; and
(2) a smart Doppler radar to calculate the distance between the automobile, truck or other vehicle, and the ob- ject(s) and to provide warning signals, which include an audible alarm beeper, a multi-language warning voice synthesizer, and a green, yellow and red LED for distance display.
The warning system 200 is shown schematically in Figure 20 and includes a signal processing unit 202, sensors 204, and display devices 206. The sensors 204 preferably include a video camera 208, a digital camera 210, an infrared sensor 212, a sonar unit 214, a proximity sensor 216 and/or most preferably, a Doppler radar unit 218. The Doppler radar unit 218 is as described above with reference to Figures 1-19. The other sensors used in the present invention are all conventional .
The signal processing unit 202 includes a signal processing unit 220 which receives signals from the sensors, and converts any analog signals into digital signals in circuit 222; and makes a rate of motion and distance calculation of objects within range of the sensors for display on one or more of the display devices in circuit and software implementation sche- matical referred to at 224. The processing unit 202 also includes a transmitter/receiver 226 for transmitting signals to and receiving instructions from remote display devices 206. In the application shown in Figure 20, the transceiver 46 is wireless. In an application such as in-house use, the data and control signals may be transmitted over conventional sig- nal lines and may use conventional protocols such as presently used to control household appliances with personal computers. The display 206 preferably includes a distance display 228, a video display 230, a multi-language voice synthe- sizer 232, a speaker 234 and a remote display 236 which is preferably a video telephone.
Referring to Figure 21, a schematic representation of the orientation of the present system in an automobile 238 is shown. Sensors 240-260 may be positioned at various locations along and near the outside of the vehicle, such as, for example, four sensors 240, 242, 246 and 248 near the rear of the vehicle 238 and behind its rear bumper, if the bumper is not metal for the Doppler radar sensors. These sensors are preferably mixed in that a given area of the car should include several types of sensors so that visual as well as range and rate of motion information may be determined concerning an object near the vehicle. Similarly, the plurality of sensors 250, 252, 254, 256, 258 and 260 may be positioned near the front and front sides of the vehicle in order to obtain visual, distance and rate of motion information regarding objects near the front of the vehicle 238. Signals from the various sensors are then sent to the central processing or signal processing unit 262, processed, and corresponding, processed signals are then sent to display devices. In the Figure 21 embodiment, an audio display device 264 is shown near the rear window of the vehicle with speaker 266 and speaker 268 providing audio information concerning objects near the vehicle. Similarly, audio and/or visual displays 270 and 272 are shown positioned on the dash board of the vehicle. Referring to Figure 22, another vehicle 274 is shown schematically and with six sensors of the present invention placed at various locations. For example, in the Figure 22 embodiment, one set of sensors 278 is positioned at the mid- die, rear of the vehicle and this combined sensor includes, preferably a Doppler radar transceiver unit as well as a video camera. The sensing unit 278 has an effective zone of coverage toward the rear of the vehicle as represented by area 280 in Figure 22. Similarly, the left rear of the vehicle in- eludes a sensing unit 282 having Doppler radar and video camera sensing capability to provide an effective zone 284 of coverage. The left front of the vehicle includes a sensing unit 286 having coverage in area 288; the front of the vehicle includes a sensing unit 290 providing coverage for area 292; the right front of the vehicle includes a sensing unit 294 providing coverage in area 296; and the right rear portion of the vehicle includes a sensing unit 298 providing coverage in area 300. Although it is preferable that each of the sensing units referred to in Figure 22 include a Doppler radar trans- ceiver and video camera, various combinations of the sensors as set forth in Figure 20 may be used.
Figure 23 shows an alternate embodiment of the present invention in which sensing units are placed at the left rear, right rear, left front and right front of the vehicle and in an environment in which the vehicle is positioned for parking on a street. In this embodiment, the vehicle may be outfitted with four sensing units as referred to, or may have additional sensing units along the side of the vehicle, which sensing units are deactivated in a parking mode of operation. The vehicle 302 includes in its right rear a sensing unit 304 which, preferably includes a video sensor and a Doppler radar transceiver providing coverage of area 306. The left rear of the vehicle 302 includes a second sensing unit 308 which pro- vides coverage of area 310. As shown in Figure 23, a vehicle 312, to the rear of vehicle 302 is .within the zone 306 of sensor 304 and zone 310 of sensor unit 308. The left front of the vehicle includes a sensor unit 314 that provides coverage of area 316 and a sensing unit 318 which provides coverage of area 320. As shown in Figure 23, another vehicle 322, parked in front of vehicle 302 is within zones 316 and 320. With the present invention, the visual and range information available to the driver of car 302 assists that driver in entering and exiting the parking space next to curb 324 and in front of car 312 and behind car 322. The visual and range information is displayed, for example, on display 326 positioned on the center dash board of the vehicle 302. As shown in Figure 23, that display may include a distance display 328, selection displays 330 and 332 indicating to the driver whether the dis- play 326 is providing information concerning the object to the rear of the vehicle or to the front of the vehicle, such as, for example, display 330, when lit, indicating that the range information displayed in display 328 is the range or distance to the vehicle 322 to the front of the car 302, and, when light 332 is lit, the display 328 indicates the distance between vehicle 312 to the rear and vehicle 302. Similarly, the display 326 may provide for two, simultaneous video displays 334 and 336, with display 334 showing the view from the rear of the car 302, and thus, the front of the car 312, and with display 336 showing the rear of the vehicle 322. As may be appreciated, various choices of displays may be made, such as providing for an automatic switching or sampling of the display to various of the sensing units, providing for a man- ual selection of the display or displays to be shown.
Referring to Figure 24, an alternate embodiment and use of the present invention will be described. Vehicle 338 is shown with four sensing units positioned at each side of the vehicle. These sensing units may be the only sensing units on the vehicle, or may be in addition to other sensing units placed in the front and rear of the vehicle, as shown and described with respect to other figures. The right front of the vehicle includes a sensing unit 340 which provides coverage of area 342; right rear sensing unit 344 provides coverage of area 346; left rear sensing unit 348 provides coverage of area 350; and left front sensing unit 352 provides coverage of area 354. As with other embodiments, it is preferred that each sensing unit include a visual sensing device, such as a video camera or digital camera and a range sensing device such as a sonar device or a Doppler radar device. Also shown in Figure 24 is a second vehicle 356 shown moving toward vehicle 338. In this embodiment, it is envisioned that the sensing units may be used to provide early warning of a collision, and in addition to providing audio/ visual displays to the driver/passengers of the vehicle 338, may also be used as input to safety devices such as, preferably air bags. For example, the DSP software may be written to provide an activation signal to the air bags of vehicle 338 upon the receipt and verification of signals indicating an impending collision between vehicle 356 and 338. This collision anticipation function would provide for various criteria to activate the air bag system, such as a combination of rate of speed and distance. Referring to Figure 25, another aspect of the present invention will be described. Vehicle 358 is shown with four sensing units and corresponding sensed zones 360 and 362; 364 and 366; 368 and 370; and 372 and 374 respectively. In this embodiment, the object of interest is the target 376 which, in this case may be someone approaching the car for purpose of breaking and entering. For example, if the car 358 is parked in a parking lot and the occupants are in a remote location, such as a restaurant or theater, the system of the present invention can be pre-set to activate a remote video phone 378, preferably digital, in the event a person 376 approaches too close to the vehicle. Similarly, the video phone 378 may be used from time-to-time to check on the security of the vehicle. For example, if the car is left outside and the occupants are inside having dinner at a restaurant, the video phone may be left on, with a constant video display of the zones 362, 366, 370 and 374 made available to the digital video phone 378. As shown in Figure 25, the sensor 360 provides visual and range data regarding the person 376 to the digital processing unit 380. The output of the digital pro- cessing unit 380 is transmitted via antenna 382 to the receiving antenna 384 of the video phone 378. Video information may be shown on display 386 and range information shown on display 388. Key pad 390 may be used to control the system to switch from one display to another, etc. Also, for example, the system may be set up so that if a predetermined combination of size of object, range of object and/or rate of speed of object near the vehicle 358 would exceed some minimum predetermined value, then the system would automatically initiate a call to the video telephone 378 and thereby provide a remote warning of possible breaking and entering, collision or other problem at the vehicle.
Referring to Figure 26, the principles of the present invention are shown adapted for a building security or safety warning system. In this embodiment, a building wall 392 having a window 394 and a door 396 is outfitted with a sensing unit 398 which provides coverage in zone 400. As with the sensing units described with respect to the previous figures, the sensing unit 398 preferably includes at least two differ- ent types of sensors, with one providing visual-type information, and one providing range information.
With reference to Figure 27, the present invention is shown as adapted to a building security system in which three sensing units are used near the end of a building to provide a wide zone of coverage. In this embodiment building 402 includes a fenced area within fence 404. First sensing unit 406 provides visual and range information in zone 408; sensing unit 410 provides visual and range information for targets or objects within zone 412; and sensing unit 414 provides visual and range information regarding objects within zone 416.
In adaptations for use in building security, the principles of the invention as described above with respect to vehicles may be directly applied. For example, various types of display devices may be placed at locations inside of the building, or may be remote-type display devices, such as a video telephone described above with reference to Figure 25. Similarly, a signal processing unit as described above will be used in a building security system, and the number and loca- tion of sensing units and display units will vary according to each particular building and design choices made by users. In addition to video phones as a visual display device, television and/or personal computer monitors may also be used. System controls may also be provided through adoption of a conventional signaling protocol, and through a universal controller for a television, the keypad or mouse for a personal computer. The control and data signals may be transmitted wireless, or through hard wires placed in the building.
The present systems may also be adapted for use by visu- ally compared persons. In such user, the system may be incorporated in a portable unit that could be carried by the user, and when activated, would provide range, speed and size or contour information. It is envisioned that this application would employ conventional video shape recognition technology to assist the user in identifying shapes of objects in zones of interest.
While the present invention has been described with what are generally considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments but to the contrary, it is intended to cover variations, modifications and equivalent arrangements included within the spirit of the invention, which are set forth in claims, and whose scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures.

Claims

What is claimed is:
1. A computer program-implemented, vehicle mounted Doppler radar warning system for determining range information regarding objects that provide a Doppler-shifted echo signal, in- eluding a transceiver adapted to produce a first Doppler analog signal reflected from an object and to produce a second Doppler analog signal reflected from the object, comprising: a computing device having a memory and adapted to process a digital signal corresponding to the phase shift of said first and second analog signals; an application program executable by the computing device; a routine in said application program for providing a digital signal representative of the distance between the transceiver and the object.
2. The system of claim 1 further including a routine in said application program for dividing said digital signal by an integer having a value in the range of 1 to 10.
3. The system of claim 1 further including a display repre- sentative of the distance between the transceiver and the object.
4. The system of claim 1 further including a routine in said application program for detecting an object within a predetermined zone and ignoring any object not in said predetermined zone.
5. The system of claim 1 further including: a first signal zero crossing detector adapted to detect the occurrence of the first analog signal crossing through a zero voltage condition from a positive voltage condition to a negative voltage condition and vice versa; and a second signal zero crossing detector adapted to detect the occurrence of the second analog signal crossing through a zero voltage condition from a positive voltage condition to a negative voltage condition and vice versa.
6. The system of claim 1 further including a variable beam width reflector adapted to vary the width of a beam transmitted from the transmitting antenna of said transceiver. 7. The system of claim 1 further adapted to operate within the 5.8 ISM frequency band.
8. The system of claim 1 further including a routine for providing a digital signal representative of the speed of the object relative to the speed of the transceiver. 9. The system of claim 1 further including a video camera adapted to obtain video images of said object.
10. The system of claim 3 wherein said display comprises light signals or audio signals.
11. The system of claim 1 further including an adjustable bracket adapted to carry said transceiver and to be adjustable in at least one direction of motion.
12. The system of claim 1 further including a remote display adapted to receive by wireless transmission the signal representative of the distance between the object and the transceiver.
13. The system of claim 1 in combination with a vehicle through attachment of said transceiver to said vehicle.
14. The system of claim 1 in combination with a building by positioning said transceiver to transmit a beam to a predetermined region inside of or adjacent to the building and to receive said Doppler-shifted signals.
15. A method of determining distance between an object and an antenna of a Doppler radar transceiver by a computer, including the steps of: receiving by a receiving antenna Doppler-shifted, sinusoidal analog signals reflected from the object, said signals varying from a negative voltage to a positive voltage and at times passing through a zero volt condition; determining times at which the analog signals are at the zero volt condition; determining from said times a signal representative of the distance between the object and the antenna to provide a raw distance signal. 16. The method of claim 15 further including the step of removing noise from said signal by the steps of: first dividing the raw distance signal by an integer having a value of from 1 to 10 to provide a divided raw distance signal; subtracting from the raw distance signal the divided raw distance signal to provide a subtracted, divided raw distance signal and repeating the above dividing and subtracting steps to provide a noise reduced distance signal.
EP98920848A 1997-04-14 1998-04-14 Doppler radar warning system Withdrawn EP0975991A4 (en)

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Application Number Priority Date Filing Date Title
US4351897P 1997-04-14 1997-04-14
US43518P 1997-04-14
PCT/US1998/007710 WO1998047022A1 (en) 1997-04-14 1998-04-14 Doppler radar warning system

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EP0975991A1 EP0975991A1 (en) 2000-02-02
EP0975991A4 true EP0975991A4 (en) 2003-02-12

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KR (1) KR19990082502A (en)
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AU (1) AU7359498A (en)
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WO (1) WO1998047022A1 (en)

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EP0975991A1 (en) 2000-02-02
TW373153B (en) 1999-11-01
AU7359498A (en) 1998-11-11
WO1998047022A1 (en) 1998-10-22
KR19990082502A (en) 1999-11-25
JP2002512689A (en) 2002-04-23
CN1239551A (en) 1999-12-22

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