ONE WAY OPTICAL RANGING SYSTEM

• US 3,576,371 A
• Filed: 02/05/1969
• Issued: 04/27/1971
• Est. Priority Date: 02/05/1969
• Status: Expired due to Term

• Current Assignee: Edward M. Ulicki
• Original Assignee: Edward M. Ulicki
• Inventors: Ulicki, Edward M.
• Application Number:
  US04/796,696
• Time in Patent Office: 811 Days
• US Class Current: 356/4.07
• CPC Class Codes: G01S 11/12 using electromagnetic waves other than radio waves

Abstract

This invention relates to a one way optical range finding system. Optical radiation at two different wavelengths, one of which is substantially unaffected by the atmosphere, is transmitted to a distant object through the atmosphere. The ratios of the received radiation signals at the two wavelengths is used to compensate for the atmospheric effects on the other transmitted wavelength.

Claims

1. A method for determining distance comprising the steps of:

transmitting radiation signals of known intensities through the atmosphere at two different frequencies, one of said frequencies being substantially unaffected by atmosphere;

receiving the signals and separating the signals into first and second received signals, determining range by detecting the attenuation of the first received signal, and utilizing the second received signal from the atmospherically unaffected signal to provide a correction factor for said first signal.

2. A system for avoiding collision between first and second airplanes, said system comprising a transmitter in said first airplanE;

a receiver in said second airplane;

said transmitter comprising a light source transmitting at least two different frequencies, one of which is optically transparent to the atmosphere, both of said signals being attenuated in accordance with distance between the airplanes, said receiver comprising means to determine the distance of said two aircrafts by utilizing the ratio of the received signals.

3. An optical range measuring system comprising means for transmitting radiation of precisely controlled intensities at first and second different optical wavelengths to a distant object through an atmospheric path, one of said wavelengths being substantially unaffected by atmospheric conditions, means for receiving reflected radiation from said object, said receiving means including means for separating the received radiation into first and second signals at said different wavelengths, and means for sensing the relative intensities of said received signals and for producing a correction signal compensating for the atmospheric effects on the other of said wavelengths.

4. The system of claim 3, in which said correction signal producing means comprises means for sensing the ratio of said first and second received signals, and further comprising means for multiplying one of said received signals by said correction signal.

5. The system of claim 4, further comprising a squaring circuit coupled to the output of said multiplier and a range indicator coupled to the output of said squaring circuit.

6. The system of claim 5, further comprising means for producing a gating signal in response to said one of said received signals, and gating means interposed between said squaring circuit and said indicator and coupled to said gating signal producing means.

7. The invention of claim 3 in which the two frequencies are approximately 8550A and 8950A.

8. The lamp of claim 3 in which the light source is a mercury doped cesium iodide light source.