Interferometric doppler radar and method for wave and water level measurement

• US 10,436,625 B2
• Filed: 01/19/2016
• Issued: 10/08/2019
• Est. Priority Date: 01/19/2015
• Status: Active Grant

• Current Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida), Texas Tech University System
• Original Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Inventors: Bridge, Jennifer Anne, Li, Changzhi, Gu, Changzhan, Davis, Justin R.
• Primary Examiner(s): McGue, Frank J
• Application Number:
  US15/000,776
• Publication Number:
  US 20160209260A1
• Time in Patent Office: 1,358 Days
• Field of Search: 342124
• CPC Class Codes: G01F 23/284 Electromagnetic waves
• CPC Class Codes: G01S 13/36 with phase comparison between the received signal and the contemporaneously transmitted signal
• CPC Class Codes: G01S 13/583 using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets
• CPC Class Codes: G01S 13/70 for range tracking only
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/88 Radar or analogous systems specially adapted for specific applications electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: G01S 7/358 using I/Q processing

Abstract

Devices, methods and systems for wave and water level measurement using a single DC (direct current)-coupled CW (continuous wave) Doppler radar for detecting water elevation changes in time when installed up to several meters from the water surface. The radar is wireless and can stream continuous data to a local PC (personal computer) or base station in range of its radio. The radar can sample up to 40 Hz and can run on batteries for continuous sampling. The radars can include multiple radar configurations of 1, 2 and 4 radar configurations. Applications for this radar can include the measurement of beach run-up, free surface elevation in tidal zones, and storm surge elevations near bridges and critical infrastructure during storm events.

Claims

1. A wireless radar sensor for measuring water surface level and characteristics in time comprising:

a CW (continuous wave) Doppler radar coupled with a transmit antenna and a receive antenna to transmit a continuous wave wireless signal without frequency modulation to a moving target of water and wirelessly receive a reflected signal having distance-dependent phase modulation;

a signal processing circuit to process the received reflected signal to generate a digital data corresponding to a water level measurement for the moving target by utilizing differentiate and cross-multiply (DACM) demodulation to recover water level information from phase information of the received reflected signal;

a power source for supplying power to the continuous wave Doppler radar; and

a micro-controller coupled with a cellular antenna to wirelessly transmit the processed digital data to a base station to detect water elevation changes by measuring the water surface level of the moving target.

2. The wireless radar sensor of claim 1, wherein the continuous wave Doppler radar comprises:

a waveform generator to produce the continuous wave wireless signal to transmit without frequency modulation;

a mixer for mixing the original transmitted signal with the received reflected signal; and

an analog-to-digital converter to convert the mixed signal to the digital data that is input to the signal processing circuit.

3. The wireless radar sensor of claim 1, further comprising:

at least one of a coarse tuning and a fine tuning circuit.

4. The wireless radar sensor of claim 2, wherein the waveform generator comprises:

a linear oscillator to generate a 2.4 GHz continuous wave signal.

5. The wireless radar sensor of claim 1, wherein the transmit antenna and the receive antenna are patch antennas.

6. The wireless radar sensor of claim 1, wherein the power source is a battery.

7. The wireless radar sensor of claim 1, wherein the power source comprises:

a solar power source; and

a rechargeable battery for storing excess solar energy.

8. The wireless radar sensor of claim 1, wherein the base station is selected from a group consisting of a personal computer, a tablet or a personal data assistant device.

9. The wireless radar sensor of claim 1, wherein the continuous wave Doppler radar is a DC-coupled continuous wave Doppler radar.

10. The wireless radar sensor of claim 1, wherein the continuous wave Doppler radar is an AC-coupled continuous wave Doppler radar.

11. The wireless radar sensor of claim 1, further comprising:

a multiple radar configuration.

12. The wireless radar sensor of claim 11, wherein the multiple radar configuration includes:

a two radar configuration.

13. The wireless radar sensor of claim 11, wherein the multiple radar configuration includes:

a four radar configuration.

14. A wireless radar sensing system for storm surge tracking and tidal zone assessment comprising:

two or more wireless radar sensors in communication, each wireless radar sensor including;

a signal generator to generate a microwave signal, wherein the microwave signal comprises a continuous wave signal,

a transmitting antenna to transmit the generated continuous wave signal without frequency modulation towards a surface of a moving target of water,

a receive antenna to receive a reflected continuous wave signal without frequency modulation from the surface of the moving target, the reflected continuous wave signal having distance-dependent phase modulation,

a mixer for combining the generated signal with the received signal to form a mixed analog signal,

a converter to convert the mixed analog signal to a digital data,

a differentiate and cross-multiply (DACM) demodulator to recover water level information from phase information of the digital data, and

a radio and antenna for transmitting the recovered water level information as transmitted data to a base station; and

the base station being configured to receive the transmitted data and to process the transmitted data to determine a surface level of the moving target.

15. A method for wave and water level measurement comprising the steps of:

generating a continuous wave signal and transmitting the continuous wave signal without frequency modulation toward a moving target of water;

receiving a reflected signal from the moving target, the reflected signal having distance-dependent phase modulation;

mixing the generated signal and received signal, down converting the mixed signal to a baseband signal;

converting the baseband signal to a digital data;

processing the digital data with a differentiate and cross-multiply (DACM) demodulator to recover water level information from phase information of the digital data, and

transmitting the recovered water level information as transmitted data to a local personal computing device or a base station; and

processing the transmitted data at the local personal computing device or the base station to determine a surface level of the moving target.

16. The wave and water level measurement method of claim 15, including the step of:

sampling at a rate of approximately 40 Hz.

17. The wave and water level measurement method of claim 15, wherein the generating step including the step of generating an approximately 2.4 GHz continuous microwave signal.