Loren D Nelson

US Patent:

6409198, Jun 25, 2002

Filed:

Oct 12, 1999

Appl. No.:

09/416565

Inventors:

Carl Scott Weimer - Littleton CO
Stuart Paul Beaton - Littleton CO
Martin Joseph OBrien - Pine CO
Loren Dean Nelson - Evergreen CO

Assignee:

Ophir Corporation - Littleton CO

International Classification:

G01J 502

US Classification:

28033904, 25033901

Abstract:

An advance in a passive, remote sensing device for measurement of atmospheric temperature utilizes an actuated modulator for periodically alternating the radiation detected by a detector at a selected infrared wavelength between the infrared radiation from the atmosphere and that from the infrared reference radiation emitted from a reference material such that the detector compares the radiation emitted from the atmosphere to that emitted by the reference material at the selected infrared wavelength in order to determine the atmosphere temperature. Preferably, the modulator is a MEMS based modulator having a movable grating formed by MEMS based fabrication techniques.

US Patent:

6509566, Jan 21, 2003

Filed:

Jun 22, 2000

Appl. No.:

09/602096

Inventors:

Paula R. Wamsley - Littleton CO
Carl S. Weimer - Littleton CO
Loren D. Nelson - Evergreen CO
Martin J. OBrien - Pine CO

Assignee:

Ophir Corporation - Littleton CO

International Classification:

G01N 2145

US Classification:

2503385, 2503418

Abstract:

An oil and gas exploration system and method for land and airborne operations, the system and method used for locating subsurface hydrocarbon deposits based upon a remote detection of trace amounts of gases in the atmosphere. The detection of one or more target gases in the atmosphere is used to indicate a possible subsurface oil and gas deposit. By mapping a plurality of gas targets over a selected survey area, the survey area can be analyzed for measurable concentration anomalies. The anomalies are interpreted along with other exploration data to evaluate the value of an underground deposit. The system includes a differential absorption lidar (DIAL) system with a spectroscopic grade laser light and a light detector. The laser light is continuously tunable in a mid-infrared range, 2 to 5 micrometers, for choosing appropriate wavelengths to measure different gases and avoid absorption bands of interference gases. The laser light has sufficient optical energy to measure atmospheric concentrations of a gas over a path as long as a mile and greater.

US Patent:

6750453, Jun 15, 2004

Filed:

May 25, 2002

Appl. No.:

10/155770

Inventors:

Loren D. Nelson - Evergreen CO
Martin J. OBrien - Pine CO

Assignee:

Ophir Corporation - Littleton CO

International Classification:

G01N 2117

US Classification:

2503385, 2504581

Abstract:

A source directs broadband modulated light into a region the free atmosphere in which target gas may be present. A gas correlation radiometer responds to light transmitted through the region. Separate radiometer channels respond to a single beam of light after transmission through the region. A beam splitter separates the beam into two beams, one directed into each of the channels. The two channels separately and simultaneously respond to a respective one of the light beams for separately and simultaneously generating signals that together indicate whether the target gas is in the free atmosphere. A method provides an optimal bandpass of an IR filter that filters the light before transmission to the radiometers. Another method uses a null factor in computing an output that determines the concentration of the target gas in the free atmosphere. Long distance detection embodiments may be borne by vehicles such as trucks or aircraft.

US Patent:

6822236, Nov 23, 2004

Filed:

Mar 18, 2004

Appl. No.:

10/803389

Inventors:

Loren D. Nelson - Evergreen CO
Martin J. OBrien - Pine CO

Assignee:

Ophir Corporation - Littleton CO

International Classification:

G01N 2135

US Classification:

2503385, 2503381

Abstract:

A method optimizes gas correlation radiometer response to trace amounts of target gas in the free atmosphere in competition with interfering gas. Operations identify spectral regions of a first absorption spectrum of the target gas, and of a second absorption spectrum of the interfering gas. A set of similarity data is determined as a function of overlap regions within the spectral region, and a set of contrast data is determined as a function of non-overlap regions within the spectral region, including a plurality of data items within each of a plurality of bandwidths, and a data item corresponding to a center wavelength within each bandwidth. Graphs correspond to each bandwidth. From one graph a center wavelength of an infrared filter is selected, and from another graph there is selected a bandwidth of the infrared filter, to configure an infrared filter for use with the gas correlation radiometer.

US Patent:

52852563, Feb 8, 1994

Filed:

Jul 28, 1992

Appl. No.:

7/921502

Inventors:

Loren D. Nelson - Evergreen CO
David C. MacPherson - Conifer CO

Assignee:

Ophir Corporation - Littleton CO

International Classification:

G01C 300

US Classification:

356342

Abstract:

Contrail detection aft of an aircraft is provided by a rear-looking ranging system carried by the aircraft. A randomly modulated laser beam is directed into a detection volume aft of the aircraft for scatter back toward a detector on the aircraft. Bistatic mounting of a laser and a telescope of the detector preclude sensing of the scattered beam forward of the detection volume. Processing of the detected scattered beam includes cross correlation and analysis to indicate the formation of the contrail aft of the aircraft.

US Patent:

48734810, Oct 10, 1989

Filed:

Feb 16, 1988

Appl. No.:

7/156614

Inventors:

Loren D. Nelson - Morrison CO
Lee A. Erb - Boulder CO
Randolph H. Ware - Boulder CO
Donald Rottner - Littleton CO

Assignee:

Radiometrics Corporation - Littleton CO

International Classification:

G01W 102
G01W 108

US Classification:

324 585R

Abstract:

A passive, multi-channel microwave radiometer includes an antenna-lens assembly for receiving, and a first waveguide designed to provide a common path for propagating, 23. 8 GHz and 31. 4 GHZ atmospheric signals. The 23. 8 GHz signal is above the frequency of relative maximum water vapor absorption and the 31. 4 GHz signal is near a relative minimum in the water vapor absorption spectrum. Circuitry is responsive to the atmospheric signals for generating output signals representing the respective water vapor and liquid content in and the temperature of the atmosphere. For realtime calibration a blackbody assembly is mounted in the near field of the antenna-lens assembly. The blackbody assembly emits known blackbody microwave signals at 23. 8 GHz, 31. 4 GHz and in the V band. The radiometer is calibrated during its normal operation by causing a mirror to select the blackbody signals for propagation along the common path.

US Patent:

55838774, Dec 10, 1996

Filed:

May 9, 1995

Appl. No.:

8/437676

Inventors:

David C. MacPherson - Conifer CO
Loren D. Nelson - Evergreen CO
Martin J. O'Brien - Bailey CO

Assignee:

Ophir Corporation - Littleton CO

International Classification:

H01S 330

US Classification:

372 4

Abstract:

Apparatus performs a method of generating one or more output laser pulses in a range of 2 to 6 microns. When a plurality of the output laser pulses are generated, a first output pulse has any selected wavelength within the range and a second output pulse is temporally closely spaced relative to the first output pulse and has a chosen wavelength differing from the selected wavelength. An oscillator laser cavity is provided with a tunable oscillator rod capable of generating initial laser pulses within a range of from 750 to 1000 nm, and a tuning element is coupled to the rod. A flashlamp is operable to pump the rod. For two pulse operation, the flashlamp has a given duration. A Q-switch provides the initial laser pulses upon operation of the tuning element and the flashlamp. A Raman device coupled to the rod shifts the wavelength of such initial laser pulse into the range of from 2 to 6 microns to form the output laser pulse having a wavelength within the range. For multiple pulses, a controller causes the Q-switch to provide first and second ones of the initial laser pulses, spaced by a time interval less than the given duration.

US Patent:

55266762, Jun 18, 1996

Filed:

Feb 7, 1995

Appl. No.:

8/385140

Inventors:

Fredrick S. Solheim - Boulder CO
Lee A. Erb - Longmont CO
Loren D. Nelson - Evergreen CO
Randolph H. Ware - Boulder CO

Assignee:

Radiometrics Corporation - Boulder CO

International Classification:

G01W 100

US Classification:

73 2901

Abstract:

Apparatus and methods for profiling atmospheric temperature, water vapor and/or cloud liquid content utilizing passive microwave remote sensing are disclosed. The apparatus includes an antenna for receiving atmospheric microwave emissions having frequencies of interest, a highly stable, tunable frequency synthesizer, and downconverting system receiving selected frequency outputs from the synthesizer and the received emissions and, responsive thereto, providing output signals indicative of the frequencies of interest and representing the profile.