Patents by Inventor David Stevenson

David Stevenson has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9398402
    Abstract: An apparatus and method are disclosed for tracking a large number of wireless terminals and for estimating the location of the terminals at each instant. Some embodiments of the present invention use a wide variety of factors to determine the order and frequency with which each wireless terminal is located. These factors include, but are not limited to, the history of the location of the wireless terminal, the time of day, and the weather.
    Type: Grant
    Filed: September 19, 2011
    Date of Patent: July 19, 2016
    Assignee: Polaris Wireless, Inc.
    Inventors: Ankit Bansal, Tarun Kumar Bhattacharya, Martin Feuerstein, Scot Douglas Gordon, Robert Lewis Martin, David Stevenson Spain, Jr.
  • Patent number: 9374801
    Abstract: A location engine that accounts for propagation-time components in an antenna system disposed between i) the base station that serves a wireless terminal and ii) the airwaves over which electromagnetic signals propagate between the antenna elements and wireless terminal. By considering and accounting for these propagation components, the location engine is able to estimate information about the antenna system, such as i) whether the antenna system is a distributed antenna system and ii) the configuration of the antenna system. Based on this estimated information, the location engine is also able to estimate adjustments that can be made to location-related measurements, and, with these adjustments, estimate the location of one or more wireless terminals.
    Type: Grant
    Filed: September 18, 2015
    Date of Patent: June 21, 2016
    Assignee: Polaris Wireless, Inc.
    Inventors: Robert Lewis Martin, David Stevenson Spain, Jr.
  • Patent number: 9301273
    Abstract: A technique for deriving timing information across wireless base stations is disclosed. After initializing values for base station time-offset parameters, a server acquires reference coordinates of a wireless terminal, which are provided from an independent source, and also acquires values for one or more time-of-occurrences of events associated with signals that travel between the wireless terminal and the base stations. The server generates predicted coordinates of the wireless terminal, based in part on the current time-offset values, by using trilateration. The server then generates updated time-offset values, based on a method of least squares, in which each residual is a difference between the reference and predicted coordinates of each wireless terminal location, for one or more wireless terminals. The server modifies the time-offset values so as to minimize the least-squares function.
    Type: Grant
    Filed: June 17, 2015
    Date of Patent: March 29, 2016
    Assignee: Polaris Wireless, Inc.
    Inventors: David Stevenson Spain, Jr., Scot Douglas Gordon
  • Publication number: 20150376890
    Abstract: An intake nozzle fits onto the suction hose of a vacuum pumper truck. The nozzle comprises a tubular housing and the rotor within the housing near the intake end. The rotor includes a hollow cylindrical canister and spiral vanes on its exterior. Ambient air enters an air tube, penetrates the side of the housing and supplies ambient air to the interior of the canister. The air exits through outlet ports into the liquid waste as it moves past under vacuum. The injected air reduces the density of the liquid waste, speeding up the pumping process and reducing the incidence of blockages.
    Type: Application
    Filed: June 27, 2014
    Publication date: December 31, 2015
    Inventors: David Stevenson, Christopher Stevenson
  • Patent number: 9220080
    Abstract: A method and system that account for one or more propagation-time components in a transmission path between a base station and a wireless terminal in a coverage area being served by the system. One such component is in the base station equipment between the radio that serves a wireless terminal and the antenna element that radiates and/or receives electromagnetic signals that involve the terminal. Another component of the transmission path is the one or more paths over which a radiated signal travels between the base station antenna element and the wireless terminal. By accounting for these propagation components through the use of measurement data provided by possibly a large number of wireless terminals, a disclosed location engine is able to derive adjusted measurements that are more representative of the propagation-time characteristic being measured by the individual terminals. These adjusted measurements can then be used to estimate the location of a wireless terminal more accurately.
    Type: Grant
    Filed: April 23, 2015
    Date of Patent: December 22, 2015
    Assignee: Polaris Wireless, Inc.
    Inventors: Robert Lewis Martin, David Stevenson Spain, Jr.
  • Patent number: 9207195
    Abstract: The application discloses systems and methods for X-ray scanning for identifying material composition of an object being scanned. The system includes at least one X-ray source for projecting an X-ray beam on the object, where at least a portion of the projected X-ray beam is transmitted through the object, and an array of detectors for measuring energy spectra of the transmitted X-rays. The measured energy spectra are used to determine atomic number of the object for identifying the material composition of the object. The X-ray scanning system may also have an array of collimated high energy backscattered X-ray detectors for measuring the energy spectrum of X-rays scattered by the object at an angle greater than 90 degrees, where the measured energy spectrum is used in conjunction with the transmission energy spectrum to determine atomic numbers of the object for identifying the material composition of the object.
    Type: Grant
    Filed: May 2, 2014
    Date of Patent: December 8, 2015
    Assignee: Rapiscan Systems, Inc.
    Inventors: Tsahi Gozani, Joseph Bendahan, Craig Matthew Brown, Willem G. J. Langevel, John David Stevenson
  • Patent number: 9173064
    Abstract: A technique for providing a location estimate of a mobile station, with increased accuracy. An unenhanced estimate of the location of a target mobile station is first obtained. A portable transmitter is then situated in an initial geographic area of interest defined by the unenhanced estimate. The portable transmitter is then tuned to transmit on a particular neighbor base station frequency being reported by the mobile station. When the portable transmitter is moved close enough to the target mobile station, the mobile station stops reporting the neighbor to the mobile's wireless telecommunications network, on account of the interference introduced by the portable transmitter being on that frequency. The estimated distance from the portable transmitter to the target mobile station depends on the transmit signal strength used by the portable transmitter. By considering these details, an enhanced estimate of the location of the mobile station can then be deduced.
    Type: Grant
    Filed: October 6, 2014
    Date of Patent: October 27, 2015
    Assignee: Polaris Wireless, Inc.
    Inventor: David Stevenson Spain, Jr.
  • Patent number: 9164162
    Abstract: A location engine that accounts for propagation-time components in an antenna system disposed between i) the base station that serves a wireless terminal and ii) the airwaves over which electromagnetic signals propagate between the antenna elements and wireless terminal. By considering and accounting for these propagation components, the location engine is able to estimate information about the antenna system, such as i) whether the antenna system is a distributed antenna system and ii) the configuration of the antenna system. Based on this estimated information, the location engine is also able to estimate adjustments that can be made to location-related measurements, and, with these adjustments, estimate the location of one or more wireless terminals.
    Type: Grant
    Filed: July 7, 2015
    Date of Patent: October 20, 2015
    Assignee: Polaris Wireless, Inc.
    Inventors: Robert Lewis Martin, David Stevenson Spain, Jr.
  • Patent number: 9088943
    Abstract: A technique for deriving timing information across wireless base stations is disclosed. After initializing values for base station time-offset parameters, a server acquires reference coordinates of a wireless terminal, which are provided from an independent source, and also acquires values for one or more time-of-occurrences of events associated with signals that travel between the wireless terminal and the base stations. The server generates predicted coordinates of the wireless terminal, based in part on the current time-offset values, by using trilateration. The server then generates updated time-offset values, based on a method of least squares, in which each residual is a difference between the reference and predicted coordinates of each wireless terminal location, for one or more wireless terminals. The server modifies the time-offset values so as to minimize the least-squares function.
    Type: Grant
    Filed: January 8, 2013
    Date of Patent: July 21, 2015
    Assignee: Polaris Wireless, Inc.
    Inventors: David Stevenson Spain, Jr., Scot Douglas Gordon
  • Publication number: 20140341341
    Abstract: The application discloses systems and methods for X-ray scanning for identifying material composition of an object being scanned. The system includes at least one X-ray source for projecting an X-ray beam on the object, where at least a portion of the projected X-ray beam is transmitted through the object, and an array of detectors for measuring energy spectra of the transmitted X-rays. The measured energy spectra are used to determine atomic number of the object for identifying the material composition of the object. The X-ray scanning system may also have an array of collimated high energy backscattered X-ray detectors for measuring the energy spectrum of X-rays scattered by the object at an angle greater than 90 degrees, where the measured energy spectrum is used in conjunction with the transmission energy spectrum to determine atomic numbers of the object for identifying the material composition of the object.
    Type: Application
    Filed: May 2, 2014
    Publication date: November 20, 2014
    Applicant: Rapiscan Systems, Inc.
    Inventors: Tsahi Gozani, Joseph Bendahan, Craig Matthew Brown, Willem G. J. Langevel, John David Stevenson
  • Publication number: 20140321588
    Abstract: The present specification discloses methods for inspecting an object. The method includes scanning an object in a two-step process. In the primary scan, a truck or cargo container (container) is completely scanned with a fan beam radiation, the transmitted radiation is measured with an array of detectors, and the transmission information and optionally the fission signatures are analyzed to determine the presence of high-density, high-Z and fissionable materials. If the container alarms in one or more areas, the areas are subjected to a secondary scan. This is done by precisely repositioning the container to the location of the suspect areas, adjusting the scanning system to focus on the suspect areas, performing a stationary irradiation of the areas, and analyzing the measured feature signatures to clear or confirm the presence of SNM.
    Type: Application
    Filed: May 9, 2014
    Publication date: October 30, 2014
    Applicant: Rapiscan Systems, Inc.
    Inventors: Tsahi Gozani, Joseph Bendahan, Michael Joseph King, Timothy John Shaw, John David Stevenson
  • Patent number: 8838137
    Abstract: A technique for estimating the location of a wireless terminal at an unknown location in a geographic region is disclosed. The technique is based on the recognition that there are location-dependent traits of electromagnetic signals. In environments where multiple antennas are radiating the same signal, as in the case of distributed antennas or host-repeater configurations, one or more possible locations of the wireless terminal can be designated as improbable based on i) a measure of the propagation delay of a signal traveling between a) a base station and b) the wireless terminal or an infrastructure antenna, or ii) the maximum distance at which a signal is detectable by the wireless terminal. Additionally, the applicable set of values for the location-dependent traits is selected based on similar criteria.
    Type: Grant
    Filed: August 30, 2012
    Date of Patent: September 16, 2014
    Assignee: Polaris Wireless, Inc.
    Inventors: Tarun Kumar Bhattacharya, David Stevenson Spain, Jr., Hassan Mohamed El-Sallabi, Robert Lewis Martin
  • Patent number: 8750454
    Abstract: The application discloses systems and methods for X-ray scanning for identifying material composition of an object being scanned. The system includes at least one X-ray source for projecting an X-ray beam on the object, where at least a portion of the projected X-ray beam is transmitted through the object, and an array of detectors for measuring energy spectra of the transmitted X-rays. The measured energy spectra are used to determine atomic number of the object for identifying the material composition of the object. The X-ray scanning system may also have an array of collimated high energy backscattered X-ray detectors for measuring the energy spectrum of X-rays scattered by the object at an angle greater than 90 degrees, where the measured energy spectrum is used in conjunction with the transmission energy spectrum to determine atomic numbers of the object for identifying the material composition of the object.
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: June 10, 2014
    Assignee: Rapiscan Systems, Inc.
    Inventors: Tsahi Gozani, Joseph Bendahan, Craig Mathew Brown, Willem Gerhardus Johannes Langeveld, John David Stevenson
  • Patent number: 8712428
    Abstract: A method of estimating the location of a wireless terminal without the addition of hardware to either the wireless terminal or to the telecommunication system's base stations is disclosed. The illustrative embodiment of the present invention is based on the observation that the signal strength of a signal from a transmitter is different at some locations, and, therefore, the location of a wireless terminal can be estimated by comparing the signal strength it currently observes against a map or database that correlates locations to signal strengths. Furthermore, the illustrative embodiment deduces the signal strength of the serving base station's control channel signal at the wireless terminal, RD, based on the principal of reciprocity.
    Type: Grant
    Filed: September 23, 2003
    Date of Patent: April 29, 2014
    Assignee: Polaris Wireless, Inc.
    Inventor: David Stevenson Spain
  • Publication number: 20140066088
    Abstract: A technique for estimating the location of a wireless terminal at an unknown location in a geographic region is disclosed. The technique is based on the recognition that there are location-dependent traits of electromagnetic signals. In environments where multiple antennas are radiating the same signal, as in the case of distributed antennas or host-repeater configurations, one or more possible locations of the wireless terminal can be designated as improbable based on i) a measure of the propagation delay of a signal traveling between a) a base station and b) the wireless terminal or an infrastructure antenna, or ii) the maximum distance at which a signal is detectable by the wireless terminal. Additionally, the applicable set of values for the location-dependent traits is selected based on similar criteria.
    Type: Application
    Filed: August 30, 2012
    Publication date: March 6, 2014
    Applicant: POLARIS WIRELESS, INC.
    Inventors: Tarun Kumar Bhattacharya, David Stevenson Spain, JR., Hassan Mohamed El-Sallabi, Robert Lewis Martin
  • Patent number: 8583141
    Abstract: A technique for estimating the location of a wireless terminal at an unknown location in a geographic region is disclosed. The technique is based on the recognition that there are traits of electromagnetic signals that are dependent on topography, the receiver, the location of the transmitter, and other factors. For example, if a particular radio station is known to be received strongly at a first location and weakly at a second location, and a given wireless terminal at an unknown location is receiving the radio station weakly, it is more likely that the wireless terminal is at the second location than at the first location.
    Type: Grant
    Filed: June 7, 2010
    Date of Patent: November 12, 2013
    Assignee: Polaris Wireless, Inc.
    Inventors: Tarun Kumar Bhattacharya, Martin Feuerstein, Scot Douglas Gordon, David Stevenson Spain, Jr.
  • Patent number: 8571577
    Abstract: A technique for estimating the location of a wireless terminal at an unknown location in a geographic region is disclosed. The technique is based on the recognition that there are traits of electromagnetic signals that are dependent on topography, the receiver, the location of the transmitter, and other factors. For example, if a particular radio station is known to be received strongly at a first location and weakly at a second location, and a given wireless terminal at an unknown location is receiving the radio station weakly, it is more likely that the wireless terminal is at the second location than at the first location.
    Type: Grant
    Filed: July 18, 2012
    Date of Patent: October 29, 2013
    Assignee: Polaris Wireless, Inc.
    Inventors: Tarun Kumar Bhattacharya, Martin Feuerstein, Scot Douglas Gordon, David Stevenson Spain, Jr.
  • Publication number: 20130283141
    Abstract: A method for building client agnostic, discoverable service oriented workflow forms for collecting spatial data input composed of spatial features and metadata is described that permits a workflow engine to export a user-defined spatial workflow represented as a service and described as XML. This workflow is composed of numerous spatial and non-spatial workflow activities chained together and includes forms for collecting user input. These forms are described using XML and can be rendered on clients irrespective of their user interface technology.
    Type: Application
    Filed: April 20, 2012
    Publication date: October 24, 2013
    Applicant: Latitude Geographics Group Ltd.
    Inventors: David Stevenson, Christian Morin, Ryan Cooney
  • Patent number: 8565786
    Abstract: A technique for estimating the location of a wireless terminal at an unknown location in a geographic region is disclosed. The technique is based on the recognition that there are traits of electromagnetic signals that are dependent on topography, the receiver, the location of the transmitter, and other factors. For example, if a particular radio station is known to be received strongly at a first location and weakly at a second location, and a given wireless terminal at an unknown location is receiving the radio station weakly, it is more likely that the wireless terminal is at the second location than at the first location.
    Type: Grant
    Filed: July 18, 2012
    Date of Patent: October 22, 2013
    Assignee: Polaris Wireless, Inc.
    Inventors: Tarun Kumar Bhattacharya, Martin Feuerstein, Scot Douglas Gordon, David Stevenson Spain, Jr.
  • Publication number: 20130221397
    Abstract: A light emitting element structure and a circuit thereof are provided. The light emitting element circuit includes a driving unit and a light emitting element. The driving unit is used for generating a driving current at a light emission period. The light emitting element includes a current transferring unit and a light emitting unit. The current transferring unit is connected with the driving unit to transfer the driving current and generate a light emitting current at the light emission period. The light emitting unit is connected with the current transferring unit and emits light in response to the light emitting current. The light emitting unit is connected with the current transferring unit and emits light in response to the light emitting current.
    Type: Application
    Filed: February 22, 2013
    Publication date: August 29, 2013
    Applicant: WINTEK CORPORATION
    Inventors: Hieng-Hsiung Huang, Chun-Ming Huang, Wen-Chun Wang, David Stevenson, Cheng-Yi Cheng, Hsi-Rong Han