Method of detecting oil spills at sea using a shipborne navigational radar

• US 4,933,678 A
• Filed: 05/30/1989
• Issued: 06/12/1990
• Est. Priority Date: 05/30/1989
• Status: Expired due to Fees

• Current Assignee: Department of Health and Human Services (State of Victoria)
• Original Assignee: The United States of America as represented by the Secretary of the Interior
• Inventors: Tennyson, Edward J.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Hellner, Mark
• Application Number:
  US07/358,049
• Time in Patent Office: 378 Days
• Field of Search: 342/22, 342/26, 342/41, 342/176
• US Class Current: 342/176
• CPC Class Codes: G01S 13/88 Radar or analogous systems specially adapted for specific applications electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00

Abstract

A method is provided wherein standard shipborne navigational radar is used for the purpose of detecting oil-spills on the sea. A homogenous sea-return image is obtained by selectively reducing the sea-clutter, rain, and haze filters of the radar while selectively increasing the gain of the radar. Because oil-spills on the surface of the water minimize the backscatter of radar waves, the location of an oil-spill may be determined by identifying characteristic distortions in the form of zones of diminished sea-return in the homogenous sea-return image. A moving oil spill may be tracked with repeated observations.

Claims

1. A method for relatively long range tracking of the location of petroleum and petroleum products on a body of water using a radar apparatus including filter means, including a sea-return filter, and haze and rain filters, for filtering radar return signals, gain control means for varying the amplification of the radar return signals, and a viewing scope for viewing said radar return signals, said method comprising:

transmitting radar signals onto the surface of a body of water;

receiving return radar signals backscattered from the body of water;

imaging said radar return signals on said radar scope to enable viewing of wave patterns corresponding to said return signals;

selectively reducing the filtering of said return signals provided by said sea-return filter and said haze and rain filters while selectively controlling said gain control mains to vary the amplitude of said radar return signals so to produce a homogeneous wave pattern at least throughout the central region of said radar scope while preventing the image on the scope from becoming bright throughout; and

detecting any distortions in said homogenous wave pattern caused by the presence of petroleum products on the rough body of water.

2. A method of tracking an oil-spill at sea, said method comprising:

positioning a radar, having variable gain and having a sea-clutter filter, in the vicinity of the oil-spill;

transmitting radar signals from said radar onto the sea;

receiving return signals from the sea in response to the transmitted radar signals;

selectively controlling said sea clutter filter while selectively increasing said gain of the radar so to provide a homogenous radar return from the sea; and

detecting any distortions in the homogenous return caused by the presence of oil on the sea.