Publication NumberUS 10509118
Assignees
  • Ohio State Innovation Foundation
  • The Regents of the University of Michigan
Filing StatusIssued Patent
US PAIR StatusPatented Case
US PAIR Status Date2019-11-26
Application Number15/494002
AvailabilityUnknown
Filing Date2017-04-21
Publication Date2019-12-17

Abstract

This disclosure relates to systems and methods for measuring wave fields of a body of water. A system can include a radiation source and an antenna that can cooperate with the radiation source to transmit a radio frequency (RF) signal to a wave field having one or more waves. The antenna can receive backscattered signals from the wave field. The system can include a local oscillator and a processor. The local oscillator downconverts the backscattered signals into baseband signals and the processor can process the baseband signals to determine a relative velocity of each of the waves of the wave field. The processor can further be programmed to identify an observed portion of the backscattered signals as bad data and remove the bad data from further processing.

Claims

  • 1. A system comprising: a radiation source to generate pulsed signals; an antenna coupled with the radiation source, wherein the antenna cooperates with the radiation source to transmit a radio frequency (RF) signal to a wave field having one or more waves based on the pulsed signals, the RF signal having a frequency and a phase offset, and wherein the antenna receives backscattered signals from the wave field; a local oscillator coupled with the antenna that downconverts the backscattered signals into baseband signals; a non-transitory memory to store machine readable instructions; and a processor coupled to the local oscillator, wherein the processor accesses the memory and executes the machine readable instructions to: average a range of the baseband signals to determine a phase offset estimate; determine phase corrected returns by conjugate multiplication of the baseband signals and the phase offset estimate; and determine a relative velocity of each of the one or more waves of the wave field based on Doppler processing using the phase corrected returns.
  • 2. The system of claim 1, wherein the machine readable instructions further cause the processor to normalize the baseband signals to determine normalized signals and thereby removing variations of amplitude in the baseband signals.
  • 3. The system of claim 2, wherein the phase offset estimate is determined based on the normalized signals for the baseband signals.
  • 4. The system of claim 1, wherein the radiation source is a magnetron, and the phase offset is induced by the magnetron.
  • 5. The system of claim 1, wherein: the antenna transmits the RF signal repetitively for a plurality of instances, wherein each instance is separated by a pulse repeat interval; and the antenna receives the backscattered signals for the plurality of instances.
  • 6. The system of claim 5, wherein the machine readable instructions further cause the processor to: determine power for the backscattered signals corresponding to a range; determine an average power for a sample set of the backscattered signals; determine a threshold using the average power; and exclude an observed one of the backscattered signals corresponding to the range from one of the average power and the Doppler processing based on an evaluation of the power of the observed one of the backscattered signals relative to the threshold.
  • 7. The system of claim 6, wherein the evaluation comprises comparing the power of the observed one of the backscattered signals relative to the threshold to determine if the power of the observed one of the backscattered signals is greater than the threshold.
  • 8. The system of claim 1, wherein the machine readable instructions further cause the processor to: determine a coherent average of the phase corrected returns over a coherent pulse interval; determine an incoherent average of the phase corrected returns over the coherent pulse interval; and exclude the phase corrected returns from the Doppler processing based on an evaluation of the coherent average of the phase corrected returns, the incoherent average of the phase corrected returns and a threshold.
  • 9. The system of claim 8, wherein the phased corrected returns are excluded from the Doppler processing when coherent average of the phase corrected returns is less than the threshold times the incoherent average of the phase corrected returns.
  • 10. The system of claim 1, wherein the machine readable instructions further cause the processor to: determine a power versus range curve using backscattered signals; and exclude an observed one of the backscattered signals from the Doppler processing based on an evaluation of a power of the backscattered signals and the power versus range curve relative to a threshold.
  • 11. A system comprising: a radiation source to generate pulsed signals; an antenna coupled with the radiation source, wherein the antenna cooperates with the radiation source to transmit a radio frequency (RF) signal to a wave field having a plurality of waves based on the pulsed signals, wherein the antenna receives backscattered signals from the wave field; a local oscillator coupled with the antenna, wherein the local oscillator downconverts the backscattered signals into baseband signals; a non-transitory memory to store machine readable instructions; and a processor coupled to the local oscillator, wherein the processor accesses the memory and executes the machine readable instructions to: identify an observed portion of the backscattered signals as bad data, based on an evaluation of a power of the observed portion of the backscattered signals relative to an expected power value; and remove the bad data from further processing.
  • 12. The system of claim 11, wherein: the antenna transmits the RF signal repetitively for a plurality of instances, wherein each instance is separated by a pulse repeat interval; and the antenna receives the backscattered signals for the plurality of instances.
  • 13. The system of claim 12, wherein the machine readable instructions further cause the processor to: detect power for the backscattered signals corresponding to a range; determine an average power for a sample set of the backscattered signals; and determine the expected power value using the average power.
  • 14. The system of claim 11, wherein the machine readable instructions further cause the processor to: average a range of the baseband signals to determine a phase offset estimate indicative of the phase offset; perform conjugate multiplication with the baseband signals and the phase offset estimate to determine phase corrected returns; determine a coherent average of the phase corrected returns over a coherent pulse interval, wherein the observed portion of the backscattered signals comprises the baseband signals over the coherent pulse interval; determine an incoherent average of the phase corrected returns over the coherent pulse interval; and evaluate the coherent average and the incoherent average.
  • 15. The system of claim 14, wherein in response to the evaluation, the power of the observed portion of the backscattered signal fails to agree with the expected power value, when the coherent average and the incoherent average fail to agree within a threshold.
  • 16. The system of claim 14, wherein the phased corrected returns are excluded from the Doppler processing when coherent average of the phase corrected returns is less than the threshold times the incoherent average of the phase corrected returns.
  • 17. The system of claim 11, wherein the machine readable instructions further cause the processor to: determine a power versus range curve using backscattered signals; and determine the expected power using the power versus range curve.
  • 18. The system of claim 17, wherein the machine readable instructions further cause the processor to exclude an observed one of the backscattered signals from the further processing based on an evaluation of a power of the backscattered signals and the power versus range curve relative to a threshold.
  • 19. The system of claim 18, wherein the further processing comprises Doppler processing.
  • 20. The system of claim 19, wherein the radiation source is a magnetron.
  • 21. A system comprising: a receiver for receiving backscattered signals from a field; a converter coupled with the receiving unit for generating baseband signals from the backscattered signals; a non-transitory memory to store machine readable instructions; and a processor coupled to the converter, wherein the processor accesses the memory and executes the machine readable instructions to: average a range of the baseband signals to determine a phase offset estimate; determine phase corrected returns by conjugate multiplication of the baseband signals and the phase offset estimate; and determine a parameter of the field using the phase corrected returns.
  • 22. The system of claim 21, further comprising: a transmitter for transmitting a RF signal toward the field that is a wave field with the backscattered signals being generated from the RF signal reaching the wave field.
  • 23. The system of claim 22, further comprising: a radiation source to generate pulsed signals; and an antenna coupled with the radiation source, wherein the antenna includes the transmitter for generating using the pulsed signals and transmitting the RF signal to the wave field, and wherein the antenna includes the receiver for receiving the backscattered signals from the wave field.
  • 24. The system of claim 23, wherein said step of determine a parameter of the wave field includes: determine a relative velocity of each of one or more waves of the wave field based on Doppler processing using the phase corrected returns.
  • 25. The system of claim 21, wherein said converter comprises a local oscillator that downconverts the backscattered signals into the baseband signals.