Vermeer Manufacturing Company, Inc.

Sprint Communications Comapny L.p.

University of Kansas

Christopher Thomas Allen

Gregory S Stump

Rongqing Hui

Douglas Lew Richards

Douglas Charles Hague

Kenneth Robert Demarest

Trenton Shuey

Xiaojun Fang

Mark Loyd Jones

Shawn Shahriar Keshmiri

Peter Adany

Masud Al Aziz

Victor Samuel Frost

Helin Ji

Lawrence James Pelz, Jr

Systems, methods, apparatuses and computer-readable storage media for navigating an unmanned aerial vehicle (UAV) using signals of opportunity are disclosed. The UAV may include a receiver for detecting a plurality of signals at two or more receiver elements. The UAV may estimate an angle of arrival (AoA) for at least two signals of the plurality of signals, and may estimate a position of the receiver based, at least in part, on the AoA for each of the at least two signals. Known locations of the transmitters that are transmitting the at least two signals may be used in conjunction with the AoAs to determine the estimate of the position of the receiver. More than two signals may be used to localize the estimated position of the receiver.

Techniques for navigating UAVs using ground-based transmitters

A low-altitude altimeter () and a method of determining low altitudes for unmanned aerial vehicles (). The altimeter includes at least two illuminators (), at least one sensor (), and a computing device (). The illuminators () emit signals which are received by the sensor () in such a way that an angle at which they are received is determinable by the computing device (). The computing device () processes each signal received by the sensor (), determines the angle at which the sensor () received the signal, and, based thereon, determines the altitude of the unmanned aerial vehicle (). When a first pair of illuminators are arranged along a fuselage axis, and a second pair of illuminators are arranged orthogonally to that axis, the computing device can combine first and second altitude, pitch angle, and roll angle measurements to provide a more refined altitude determination.

Low-altitude altimeter and method

An optical homodyne detection scheme for FM chirped lidar is described. The system performs de-chirping within a photodetector, and it does not require high-speed photo-detection or RF mixing. Embodiments are also described for dealing with phase noise.

Coherent detection scheme for FM chirped laser radar

A monitoring system is described that is comprised of a processing system and a database system. The database system is configured to store identities for a plurality of channels in the communication network. The processing system identifies an error on a first channel of the plurality of channels. The processing system identifies a second channel of the plurality of channels that is adjacent to the first channel based on the database system and determines if an error occurs on the second channel. The processing system identifies a third channel of the plurality of channels based on database system and determines if an error occurs on the third channel. The processing system identifies polarization-mode dispersion based on determining the error occurs on the second channel and determining the error does not occur on the third channel.

Identification of polarization-mode dispersion on a communication network

An apparatus and method for horizontally drilling for detecting subsurface features and avoiding such features during closed-loop control of an underground drilling machine. A horizontal drilling system includes a base machine capable of propelling a drill pipe rotationally and longitudinally underground. A cutting tool system is coupled to the drill pipe, and a control system controls the base machine. A detector is employed to detect a subsurface feature. A communication link is utilized for transferring data between the detector and the control system. The control system uses the data generated by the detector to modify control of the base machine in response to detection of the subsurface feature.

Apparatus and method for horizontal drilling

A receiver system processes a received optical signal that carries user information. The receiver system includes a splitter, a first converter, a second converter, and a detection system. The splitter splits the received optical signal based on polarization into a first optical signal and a second optical signal. The first converter converts the first optical signal into a corresponding first electrical signal. The second converter also converts the second optical signal into a corresponding second electrical signal. The detection system applies radio frequency detection to the first electrical signal to generate a third electrical signal. The detection system applies radio frequency detection to the second electrical signal to generate a fourth electrical signal. The detection system then combines the third electrical signal and the fourth electrical signal to form a fifth electrical signal that carries the user information.

Optical systems with diversity detection

An apparatus and method for horizontally drilling provides for detecting subsurface features and avoiding such features during closed-loop control of an underground drilling machine. A horizontal drilling system includes a base machine capable of propelling a drill pipe rotationally and longitudinally underground. A cutting tool system is coupled to the drill pipe, and a control system controls the base machine. A detector is employed to detect a subsurface feature. A communication link is utilized for transferring data between the detector and the control system. The control system uses the data generated by the detector to modify control of the base machine in response to detection of the subsurface feature.

A system identifies a polarization-mode dispersion (PMD) event in an optical fiber by determining error conditions in proximate wavelengths. The system includes an optical interface and a PMD identification system. The optical interface receives an optical signal from the optical fiber wherein the optical signal is wavelength division multiplexed with a plurality of wavelengths. The PMD identification system determines whether a first error condition exists in a first one of the wavelengths of the optical signal. The PMD identification system also determines whether a second error condition exists in a second one of the wavelengths of the optical signal wherein the second one of the wavelengths is proximate to the first one of the wavelengths. The PMD identification system also determines whether an acceptable condition exists in a third one of the wavelengths of the optical signal that is not proximate to the first one and the second one of the wavelengths of the optical signal. The PMD identification system then determines the presence of the polarization-mode dispersion event in the optical fiber based on the first error condition, the second error condition, and the acceptable condition.

Identifying a polarization-mode dispersion event

An apparatus and method for determining a location and an orientation of an underground boring tool by employment of a radar-like probe and detection technique. The boring tool is provided with a device which generates a specific signature signal in response to a probe signal transmitted from above the ground. Cooperation between the probe signal transmitter at ground level and the signature signal generating device provided at the underground boring tool results in accurate detection of the boring tool location and, if desired, orientation, despite the presence of a large background signal. Precision detection of the boring tool location and orientation enables the operator to accurately locate the boring tool during operation and, if provided with a directional capacity, avoid buried obstacles such as utilities and other hazards. The signature signal produced by the boring tool may be generated either passively or actively, and may be a microwave or an acoustic signal. Further, the signature signal may be produced in a manner which differs from that used to produce the probe signal in one or more ways, including timing, frequency content, information content, or polarization.

Apparatus and method for detecting a location and an orientation of an underground boring tool

Apparatus and method for controlling an underground boring tool

The invention is a method and apparatus that provides for the control of optical signals in a polarization-independent manner using birefringence. The invention includes an optical coupler connected to a birefringence element by an optical path loop. The optical coupler and optical path loop could be a Sagnac interferometer. The birefringence element affects the phase velocity of optical signals based on a control signal, and it can introduce a relative phase shift between optical signals propagating around the loop. The optical signals can be routed based on this phase shift.

Method and apparatus for controlling an optical signal

Apparatus and method for detecting a location and an orientation of an

An apparatus and method for locating an underground object or structure by employment of a radar-like probe and detection technique is disclosed. The underground structure is provided with a device which generates a specific signature signal in response to a probe signal transmitted from above the ground. Cooperative action between the probe signal transmitter at ground level and the signature signal generating device provided on the underground object provides for accurate detection of the subsurface object, despite the presence of a large background noise signal. The depth and, if desired, orientation of the underground object may also be determined using the signature signal generated by the signature signal generating device mounted to the underground object. Orientation information may be encoded on the signature signal or transmitted as an information signal separate from the signature signal. The probe signal may be microwave or acoustic. The signature signal produced by the signature signal generating device mounted to the underground object may be generated either passively or actively. Further, the signature signal may be produced in a manner which differs from the probe signal in one or more ways, including phase, frequency content, information content, or polarization. Also, the signature signal generating device may produce both location and orientation information, without the need for a separate orientation detecting device. Alternatively, orientation and location information may be produced by independent orientation detection and signature signal generating devices.

Apparatus and method for detecting an underground structure

An apparatus and method for locating an underground boring tool using a radar-like probe and detection technique. A boring tool is provided with a device which generates a specific signature signal in response to a probe signal transmitted from above the ground. Cooperative operation between the probe signal transmitter at ground level and a signature signal generator disposed within the boring tool provides for the accurate locating of the boring tool, despite the presence of a large background signal. The signature signal produced by the boring tool may be generated either passively or actively, and in a manner which differs from the probe signal in one or more ways, including timing, frequency content, or polarization. A survey of a boring site, made either prior to or during the boring operation, provides data related to the characteristics of the ground medium subjected to the survey and the identification of underground hazards, such as buried utilities. Knowledge of ground characteristics enables estimates of boring productivity and cost to be made. Accurate surveys of planned boring pathways can be made and compared, either contemporaneously or subsequently, against the accurately measured position of the boring tool during a boring operation. The direction of the boring tool may be adjusted in response to the measured position in order to maintain the boring tool along the planned pathway and at an optimum boring rate.

Growing community of inventors

Lawrence, KS, United States of America

Christopher Thomas Allen