Patents by Inventor Shankar V. Achanta

Shankar V. Achanta 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: 10379500
    Abstract: Systems and methods for detecting the failure of a precision time source using an independent time source are disclosed. Additionally, detecting the failure of a GNSS based precision time source based on a calculated location of a GNSS receiver is disclosed. Moreover, the system may be further configured to distribute a time derived from the precision time source as a precision time reference to time dependent devices. In the event of a failure of the precision time source, the system may be configured to distribute a time derived from a second precision time source as the precision time signal during a holdover period.
    Type: Grant
    Filed: August 22, 2017
    Date of Patent: August 13, 2019
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Shankar V. Achanta, David E. Whitehead, Henry Loehner
  • Patent number: 10288741
    Abstract: The present application discloses detecting manipulation of GNSS signals using a second time source. If two or more GNSS constellation signals are being detected, the phase error between the GNSS constellation signals may be monitored. When the phase error drifts, then manipulation is determined. The integrity of a GNSS constellation signal may be monitored using an internal time source such as a crystal oscillator by monitoring a slope of the free running counter at the detected rising edges of a pulse-per-second signal from the GNSS constellation. If more than two GNSS constellations are monitored, a voting scheme may be used to determine the manipulated GNSS constellation.
    Type: Grant
    Filed: April 26, 2017
    Date of Patent: May 14, 2019
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventor: Shankar V. Achanta
  • Patent number: 10161986
    Abstract: Disclosed herein are systems for monitoring and protecting an electric power system using a plurality of conductor-mounted detectors (CMDs). In one embodiment, a plurality of CMDs are coupled to an electrical conductor. Each CMD may harvest power from the electrical conductor and may monitor electrical current in the conductor. When the electrical current in the conductor exceeds a fault current threshold a fault signal may be transmitted. A receiver in communication with each of the plurality of CMDs may receive the fault signal from at least one of the plurality of CMDs. A protective action may be generated and implemented to clear the fault. A portion of the electric power system affected by the fault may be determined based on identification of each of the plurality of CMDs to transmit the fault signal.
    Type: Grant
    Filed: October 13, 2017
    Date of Patent: December 25, 2018
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Edmund O. Schweitzer, III, Shankar V. Achanta, David E. Whitehead
  • Patent number: 10122487
    Abstract: Systems and methods for detecting the failure of a precision time source using an independent time source are disclosed. Additionally, detecting the failure of a GNSS based precision time source based on a calculated location of a GNSS receiver is disclosed. Moreover, the system may be further configured to distribute a time derived from the precision time source as a precision time reference to time dependent devices. In the event of a failure of the precision time source, the system may be configured to distribute a time derived from a second precision time source as the precision time signal during a holdover period.
    Type: Grant
    Filed: November 11, 2016
    Date of Patent: November 6, 2018
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: David E. Whitehead, Shankar V. Achanta, Henry Loehner
  • Publication number: 20180287658
    Abstract: Systems, methods, and apparatuses for one-way communications are disclosed. A system includes a transmitter, a first receiver, and a second receiver. A transmitter transmits one or more messages on one or more channels according to a predetermined, pseudo-random channel hopping protocol. The receivers receive said transmissions according to the order of the pseudo-random channel hopping protocol. Methods for re-syncing the one-way system in the event of a power loss or other event causing desynchronization. Default waiting channels are established for the receivers once a certain number of channel detection periods according to the one-way communication protocol result in no detected signals.
    Type: Application
    Filed: March 29, 2018
    Publication date: October 4, 2018
    Applicant: Schweitzer Engineering Laboratories, Inc.
    Inventors: Miralem Cosic, Shankar V. Achanta, Raymond W. Rice, Chen Zhu, Bryson R. Bechtel
  • Publication number: 20180106851
    Abstract: Disclosed herein are systems for monitoring and protecting an electric power system using a plurality of conductor-mounted detectors (CMDs). In one embodiment, a plurality of CMDs are coupled to an electrical conductor. Each CMD may harvest power from the electrical conductor and may monitor electrical current in the conductor. When the electrical current in the conductor exceeds a fault current threshold a fault signal may be transmitted. A receiver in communication with each of the plurality of CMDs may receive the fault signal from at least one of the plurality of CMDs. A protective action may be generated and implemented to clear the fault. A portion of the electric power system affected by the fault may be determined based on identification of each of the plurality of CMDs to transmit the fault signal.
    Type: Application
    Filed: October 13, 2017
    Publication date: April 19, 2018
    Applicant: Schweitzer Engineering Laboratories, Inc.
    Inventors: Edmund O. Schweitzer, III, Shankar V. Achanta, David E. Whitehead
  • Publication number: 20170351223
    Abstract: Systems and methods for detecting the failure of a precision time source using an independent time source are disclosed. Additionally, detecting the failure of a GNSS based precision time source based on a calculated location of a GNSS receiver is disclosed. Moreover, the system may be further configured to distribute a time derived from the precision time source as a precision time reference to time dependent devices. In the event of a failure of the precision time source, the system may be configured to distribute a time derived from a second precision time source as the precision time signal during a holdover period.
    Type: Application
    Filed: August 22, 2017
    Publication date: December 7, 2017
    Applicant: Schweitzer Engineering Laboratories, Inc.
    Inventors: Shankar V. Achanta, David E. Whitehead, Henry Loehner
  • Publication number: 20170328945
    Abstract: A conductor-mounted device (CMD) used to signal an intelligent electronic device (IED) of the existence of a fault on a portion of the electric power delivery system is described herein. The CMD may provide a heartbeat signal to the IED. The CMD may provide a fault signal to the IED. The CMD may be powered via a parasitic current draw on the conductor to which it is mounted. An IED may use a fault signal and/or LOC signal from a CMD to coordinate a high-impedance fault detection and/or downed line events.
    Type: Application
    Filed: May 9, 2017
    Publication date: November 16, 2017
    Applicant: Schweitzer Engineering Laboratories, Inc.
    Inventor: Shankar V. Achanta
  • Patent number: 9813173
    Abstract: The time signal verification and distribution device disclosed herein verifies and distributes a time signal to consuming devices. The device determines a time quality status of a first and second time signal, calculates a difference between a first and a second time signal, and compares the difference to a predetermined threshold. Based on the time quality status and the comparison, the time signal verification and distribution device distributes a time signal to a plurality of time signal consuming devices. Exceeding the predetermined threshold may indicate a spoofing attack or other problem with the time signals.
    Type: Grant
    Filed: October 5, 2015
    Date of Patent: November 7, 2017
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Shankar V. Achanta, Srinivas Achanta, David E. Whitehead
  • Publication number: 20170285170
    Abstract: The present application discloses detecting manipulation of GNSS signals using a second time source. If two or more GNSS constellation signals are being detected, the phase error between the GNSS constellation signals may be monitored. When the phase error drifts, then manipulation is determined. The integrity of a GNSS constellation signal may be monitored using an internal time source such as a crystal oscillator by monitoring a slope of the free running counter at the detected rising edges of a pulse-per-second signal from the GNSS constellation. If more than two GNSS constellations are monitored, a voting scheme may be used to determine the manipulated GNSS constellation.
    Type: Application
    Filed: May 6, 2013
    Publication date: October 5, 2017
    Applicant: Schweitzer Engineering Laboratories, Inc.
    Inventor: Shankar V. Achanta
  • Patent number: 9759816
    Abstract: The present application discloses detecting manipulation of GNSS signals using a second time source. If two or more GNSS constellation signals are being detected, the phase error between the GNSS constellation signals may be monitored. When the phase error drifts, then manipulation is determined. The integrity of a GNSS constellation signal may be monitored using an internal time source such as a crystal oscillator by monitoring a slope of the free running counter at the detected rising edges of a pulse-per-second signal from the GNSS constellation. If more than two GNSS constellations are monitored, a voting scheme may be used to determine the manipulated GNSS constellation.
    Type: Grant
    Filed: May 6, 2013
    Date of Patent: September 12, 2017
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventor: Shankar V. Achanta
  • Patent number: 9760062
    Abstract: Systems and methods for detecting the failure of a precision time source using an independent time source are disclosed. Additionally, detecting the failure of a GNSS based precision time source based on a calculated location of a GNSS receiver is disclosed. Moreover, the system may be further configured to distribute a time derived from the precision time source as a precision time reference to time dependent devices. In the event of a failure of the precision time source, the system may be configured to distribute a time derived from a second precision time source as the precision time signal during a holdover period.
    Type: Grant
    Filed: October 17, 2013
    Date of Patent: September 12, 2017
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Shankar V. Achanta, David E. Whitehead, Henry Loehner
  • Publication number: 20170227651
    Abstract: The present application discloses detecting manipulation of GNSS signals using a second time source. If two or more GNSS constellation signals are being detected, the phase error between the GNSS constellation signals may be monitored. When the phase error drifts, then manipulation is determined. The integrity of a GNSS constellation signal may be monitored using an internal time source such as a crystal oscillator by monitoring a slope of the free running counter at the detected rising edges of a pulse-per-second signal from the GNSS constellation. If more than two GNSS constellations are monitored, a voting scheme may be used to determine the manipulated GNSS constellation.
    Type: Application
    Filed: April 26, 2017
    Publication date: August 10, 2017
    Applicant: Schweitzer Engineering Laboratories, Inc.
    Inventor: Shankar V. Achanta
  • Patent number: 9709680
    Abstract: Systems and methods for detecting the failure of a precision time source using an independent time source are disclosed. Additionally, detecting the failure of a GNSS based precision time source based on a calculated location of a GNSS receiver is disclosed. Moreover, the system may be further configured to distribute a time derived from the precision time source as a precision time reference to time dependent devices. In the event of a failure of the precision time source, the system may be configured to distribute a time derived from a second precision time source as the precision time signal during a holdover period.
    Type: Grant
    Filed: September 4, 2013
    Date of Patent: July 18, 2017
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Shankar V. Achanta, David E. Whitehead, Henry Loehner
  • Patent number: 9709682
    Abstract: The present application discloses detecting manipulation of GNSS signals using a second time source. If two or more GNSS constellation signals are being detected, the phase error between the GNSS constellation signals may be monitored. When the phase error drifts, then manipulation is determined. The integrity of a GNSS constellation signal may be monitored using an internal time source such as a crystal oscillator by monitoring a slope of the free running counter at the detected rising edges of a pulse-per-second signal from the GNSS constellation. If more than two GNSS constellations are monitored, a voting scheme may be used to determine the manipulated GNSS constellation.
    Type: Grant
    Filed: May 6, 2013
    Date of Patent: July 18, 2017
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventor: Shankar V. Achanta
  • Patent number: 9599719
    Abstract: Disclosed herein is a system for detecting manipulation of a GNSS signal and mitigating against such manipulation. A GNSS receiver receives GNSS signals from a plurality of GNSS satellites, and calculates event times for each GNSS satellite. The GNSS receiver then compares a next event time for a particular GNSS satellite with an expected next event time for the particular GNSS satellite. If the difference between the expected next event time and the next event times exceeds a predetermined threshold, then the GNSS receiver indicates that signal integrity may be compromised.
    Type: Grant
    Filed: October 14, 2013
    Date of Patent: March 21, 2017
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Shankar V. Achanta, David E. Whitehead, Francis J. Cooper
  • Patent number: 9590411
    Abstract: The present disclosure provides systems and methods for synchronizing the time signals of master and remote IEDs using a radio link. According to one embodiment, a master IED may transmit an adjusted time signal to a remote IED via a radio signal. The master IED may determine a propagation delay between the master IED and a remote IED. The master IED may then adjust a master time signal by the propagation delay and transmit the adjusted time signal to the remote IED. Alternatively, a remote IED may request and receive a master time signal from a master IED via a radio signal. The remote IED may then determine the propagation delay and adjust the received master time signal accordingly. According to various embodiments, the time signal of a master and remote IED may be synchronized to within at least one millisecond.
    Type: Grant
    Filed: December 15, 2011
    Date of Patent: March 7, 2017
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventor: Shankar V. Achanta
  • Publication number: 20170063482
    Abstract: Systems and methods for detecting the failure of a precision time source using an independent time source are disclosed. Additionally, detecting the failure of a GNSS based precision time source based on a calculated location of a GNSS receiver is disclosed. Moreover, the system may be further configured to distribute a time derived from the precision time source as a precision time reference to time dependent devices. In the event of a failure of the precision time source, the system may be configured to distribute a time derived from a second precision time source as the precision time signal during a holdover period.
    Type: Application
    Filed: November 11, 2016
    Publication date: March 2, 2017
    Inventors: David E. Whitehead, Shankar V. Achanta, Henry Loehner
  • Patent number: 9520860
    Abstract: Systems and methods for detecting the failure of a precision time source using an independent time source are disclosed. Additionally, detecting the failure of a GNSS based precision time source based on a calculated location of a GNSS receiver is disclosed. Moreover, the system may be further configured to distribute a time derived from the precision time source as a precision time reference to time dependent devices. In the event of a failure of the precision time source, the system may be configured to distribute a time derived from a second precision time source as the precision time signal during a holdover period.
    Type: Grant
    Filed: October 18, 2013
    Date of Patent: December 13, 2016
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: David E. Whitehead, Shankar V. Achanta, Henry Loehner
  • Patent number: 9425652
    Abstract: Disclosed herein are a variety of various systems and method for adaptive holdover time error estimation. In one embodiment a system may include a local time source configured to generate a local time signal and an external time source interface configured to receive an external time signal. A time source subsystem may be configured to compare the local time signal and the external time signal and to determine a temperature-dependent signal drift rate of the local time signal relative to the external time signal. The time source subsystem may be a time-dependent signal drift rate of the local time signal relative to the external time signal. A holdover subsystem may detect a loss of reception of the external time signal during a holdover period and may estimate a total maximum error based on an estimated maximum time-dependent error and an estimated maximum temperature-dependent error.
    Type: Grant
    Filed: June 16, 2014
    Date of Patent: August 23, 2016
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Daniel B. Rippon, Shankar V. Achanta