DOPPLER RADAR FOR LAND VEHICLES

• US 3,833,906 A
• Filed: 02/14/1972
• Issued: 09/03/1974
• Est. Priority Date: 02/14/1972
• Status: Expired due to Term

• Current Assignee: Carroll F. Augustine
• Original Assignee: Carroll F. Augustine
• Inventors: Augustine, Carroll F.
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Birmiel, H. A.
• Application Number:
  US05/226,107
• Time in Patent Office: 932 Days
• Field of Search: 343/8,9,7ED,753,783,784
• US Class Current: 342/59
• CPC Class Codes: G01S 13/60 wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed, drift angle, ground track G01S13/64 takes precedence

Abstract

A doppler radar system for automobiles and the like which is especially adapted for measuring speed of the vehicle. Preferably, two radar antennas are utilized, one of which is forwardly and downardly directed and the other of which is rearwardly and downwardly directed. The doppler signals from each of the antennas are summed to provide a velocity signal which is compensated for changes in the pitch of the vehicle. Each of the antennas includes a horn and a dielectric lens for the horn for focusing the transmitted energy at the traveling surface.

Claims

1. In combination with a land vehicle traveling along a roadway for the vehicle, a system comprising:

first generating and doppler detecting means including a diode for generating first high frequency electromagnetic energy and for providing a first doppler signal representative of the difference in frequencies between a returned part of said first high frequency energy and a generated part of said firSt high frequency energy;

first directing and receiving means including a first horn structure cooperative with said first generating and doppler detecting means for directing at least a portion of said first high frequency energy along a first axis intersecting said roadway and receiving along said first axis a returned part of said first high frequency energy directed along said first axis which is provided to said first generating and doppler detecting means, said first horn structure having an open end directed at said roadway with a first dielectric lens position in said opening and sealingly engaged therewith for protecting said first generating and doppler detecting means, said lens being spaced a predetermined distance from said roadway and having a focal length established in accordance with said distance for focusing said high frequency energy generally at said roadway so as to concentrate said high frequency energy into a restricted area at said roadway;

second generating and doppler detecting means including a second diode for generating second high frequency electromagnetic energy and for providing a second doppler signal representative of the difference in frequencies between a returned part of said second high frequency energy and a generated part of said second high frequency energy;

second directing and receiving means including a second horn structure cooperative with said second generating and doppler detecting means for directing at least a portion of said second high frequency energy along a second axis intersecting with said roadway and receiving along said second axis a returned part of said second high frequency energy directed along said second axis, said second axis having a predetermined divergence from said first axis, said second horn structure having an open end directed at said roadway with a second dielectric lens position in said opening and sealingly engaged therewith for protecting said second generating and doppler detecting means, said lens being spaced a predetermined distance from said roadway and having a focal length established in accordance with said distance for focusing said high frequency energy generally at said roadway so as to concentrate said high frequency energy into a restricted area at said roadway; and

means for accomplishing one of a summation and subtraction of said first and second doppler signals for providing an output signal representative of the one of the sum and difference, respectively, of said first and second doppler signals whereby an operating condition of said vehicle is determinable from said output signal.

2. A system according to claim 1 wherein said first and second doppler signals are summed to provide said output signal.

3. A system according to claim 1 wherein said first and second doppler signals are subtracted to provide said output signal.

4. A system according to claim 1 wherein said first axis is generally forwardly directed with respect to the travel of said land vahicle along vehicle roadway and said second axis is generally rearwardly directed with respect to the travel of said land vehicle along said roadway.

5. A system according to claim 4 wherein said land vehicle has a longitudinal axis and wherein said first and second axes are substantially aligned with said longitudinal axis of said land vehicle.

6. A system according to claim 4 wherein said land vehicle is adapted for changes in pitch and wherein said first and second doppler signals are summed for providing said output signal whereby said output signal is related to the velocity of said land vehicle along said roadway and is compensated for changes in the pitch of said land vehicle.

7. A system according to claim 6 wherein said land vehicle has a longitudinal axis and wherein said first and second axes are substantially aligned with said longitudinal axis of said land vehicle.

8. A system according to claim 1 wherein said first and second axes are laterally divergent whereby said outpUt signal is representative of lateral drift of said land vehicle.

9. A system according to claim 1 wherein said means for accomplishing one of a summation and subtraction of said first and second doppler signals comprises:

first converting means for converting said first doppler signal into a pulse train having a repetition rate representative of the frequency of said first doppler signal;

second converting means for converting said second doppler signal into a pulse train having a repetition rate representative of the frequency of said second doppler signal; and

means for accomplishing one of a summation and subtraction of said first and second pulses for providing said output signal.

10. A system according to claim 9 wherein each of said lenses has a second focal length established to be generally the distance between said lens and said respective generating and doppler detecting means.

11. A system according to claim 1 wherein each of said horns diverges towards said opening and each further includes an opposite opening communicating with said respective generating and doppler detecting means.

12. A system according to claim 1 wherein each of said lenses includes a first lens portion for focusing said high frequency energy at said roadway and a second lens portion for focusing received high frequency energy generally in the vicinity of said respective generating and doppler detecting means.