Sonic ranging/detection system employing varied beamwidth

• US 4,551,825 A
• Filed: 11/01/1982
• Issued: 11/05/1985
• Est. Priority Date: 11/01/1982
• Status: Expired due to Fees

• Current Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Original Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Inventors: Biber, Conrad H.
• Primary Examiner(s): Farley, Richard A.
• Application Number:
  US06/438,052
• Time in Patent Office: 1,100 Days
• Field of Search: 367/101, 367/102, 367/87, 367/99, 367/116, 367/103, 343/5 PD
• US Class Current: 367/101
• CPC Class Codes: G01S 15/102 using transmission of pulses having some particular characteristics
• CPC Class Codes: G01S 15/87 Combinations of sonar systems
• CPC Class Codes: G01S 15/88 Sonar systems specially adapted for specific applications seismic or acoustic prospecting or detecting G01V1/00

Abstract

A sonic ranging and/or object detection system, particularly useful for the blind, periodically employs widely different pulse frequencies in order to distinguish between objects located directly in front of the energy transmitting portion of this system and those located to either side. The higher frequency pulses produce a relatively narrow sonic energy beam width for detecting centrally located objects and the lower frequency pulses produce a relatively broad sonic energy beam width for detecting lateral or off-center objects. One or more time-related audible tones are superimposed on each of the pulse frequencies for range determining and/or object distinguishing purposes.

Claims

1. Object detection apparatus comprising means for transmitting a urst of sonic energy at more than one frequency toward a remote object and detecting a reflection of said energy from said object, said tramsmitting means including an electrostatic transducer having a frequency dependent transmission pattern, and means for alternately changing the sonic energy transmission frequency between relatively high and low frequencies wherein a portion of said transmission pattern includes a central beam portion defined by a beam angle and said beam portion is alternated between relatively narrow and wide beam angles in response to said alternating sonic energy transmission frequencies;

means responsive to the transmission and reception of said narrow central beam angle burst of sonic energy in a particular direction and at a first frequency toward a remote object for generating a signal respresentative of object distance;

means responsive to said object distance signal for generating an audible signal whose pitch is varied in accordance with the distance to said remote object;

means responsive to the transmission and reception of said wide central beam angle burst of sonic energy at a second frequency in said particular direction for generating a signal respresentative of the presence of an object located in a direction at an angle to said particluar direction; and

means responsive to said object presence signal for generating an audible signal, of constant pitch, indicating the presence of an object in said angled direction.

2. Object detection apparatus comprising means for transmitting energy toward one or more objects in the direction of travel and for detecting a reflection from such objects, said transmitting means including a transducer energizeable for producing a forwardly directed transmission pattern having at least a central beam portion whose beamwidth varies in accordance with the frequency of energization, and actuatable means for sequenctially energizing said transducer, with at least a first and a second frequency to vary the beamwidth accordingly and thereby detects objects centrally located before said transducer responsive to one of said energizations and more laterally located objects responsive to another of said energizations;

and

means responsive to detection of a reflection in response to said one energization for producing a signal varying with range of the object so detected and in response to detection of a reflection in response to said other energization for producing a constant signal indicative of mere detection of an object.

3. Apparatus for detecting and distinguishing between forwardly positioned objects and other slightly laterally thereof, said apparatus comprising:

means for transmitting periodic bursts of energy in the direction of travel;

means for varying the frequency of said bursts to periodically provide at least a narrow and a wide beam pattern of said burst; and

means for detecting echoes from narrow and wide beam patterns and for producing a first signal due to an echo from said narrow beam bursts and a second signal different from said first signal responsive to an echo from said wide beam bursts.