High-Resolution High-Dynamic Range Doppler-Effect Measurement Using Modulated Carrier Signals

• US 20180206075A1
• Filed: 01/17/2018
• Published: 07/19/2018
• Est. Priority Date: 01/17/2017
• Status: Active Grant

• Current Assignee: PhasorLab Inc.
• Original Assignee: PhasorLab Inc.
• Inventors: Demirdag, Cuneyt, Park, Joshua C., Wolverton, Glen, Topiwala, Devang
• Granted Patent: US 11,412,347 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 11/10 using Doppler effect
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
• CPC Class Codes: G01S 5/0257 Hybrid positioning by coordinating position lines of different shape G01S5/12
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 4/027 using movement velocity, acceleration information
• CPC Class Codes: H04W 4/46 for vehicle-to-vehicle communication [V2V]
• CPC Class Codes: H04W 84/005 Moving wireless networks

Abstract

Described in this document are ways to accomplish high resolution and high dynamic range Doppler-Effect measurements for use in wireless communications and other applications such as positioning. Doppler Effect (interchangeably called Doppler shift or Doppler frequency shift) measurements have traditionally been done with purpose-built devices, such as pulse-based radars. Presented in this document are alternative ways to incorporate Doppler frequency shift measurement using modulated carrier signals with a conventional radio, without additional hardware.

Claims

1. A method, comprising:

generating a baseband information signal by mixing a received modulated carrier signal with a local oscillator (LO) signal having an LO frequency, the modulated carrier signal being an in-phase signal and quadrature signal uncorrelated with each other and derived from different input data sets;

obtaining baseband signal samples of the baseband information signal having an in-phase signal sample and a quadrature signal sample;

determining an offset frequency rotation based on an estimated correlation between the in-phase signal samples and the quadrature signal samples; and

,

generating a relative speed by subtracting the offset frequency rotation from a measured frequency offset,

thereby determining the relative speed when the received modulated carrier signal is received at a stationary receiver,

wherein the received modulated carrier signal is a quadrature-modulated signal with arbitrary orthogonal in-phase and quadrature signal components.

2. The method of claim 11, wherein determining the offset frequency rotation further comprises calculating:

Σ

_k=1^N{|I_R,i(k)|·

|Q_R,i(k)|},

where I_R,i refers to an in-phase part of an ith error-corrected data set and Q_R,i refers to a quadrature part of the ith error-corrected data set.

3. The method of claim 11, wherein determining the offset frequency rotation further comprises calculating:

Σ

_k=1^N{(I_R,i(k))²(Q_R,i(k))²},

where I_R,i refers to an in-phase part of an ith error-corrected data set and Q_R,i refers to a quadrature part of the ith error-corrected data set.

4. The method of claim 1, wherein the relative speed is walking speed.

5. The method of claim 1, further comprising performing one-way measurement where only the source transmits and receives the reflected wave from a target which doesn'"'"'t transmit or receive.

6. The method of claim 1, further comprising performing two-way measurement where 2 transceiver nodes are collaborating and start to move while synchronized in time and frequency.

7. The method of claim 1, further comprising performing two-way measurement where 2 transceiver nodes are collaborating and start to move before becoming synchronized in time and frequency.

8. The method of claim 1, further comprising performing two-way measurements with MIMO transceivers to add angle of arrival measurements to help in positioning applications.

9. The method of claim 1, further comprising performing two-way measurements in a network where nodes can move while unsynchronized in time and frequency.

10. The method of claim 1, further comprising performing two-way measurements for high data rate applications in cellular or data networks.

11. The method of claim 1, vehicle-to-Infrastructure (V2I), Vehicle-to-Vehicle (V2V) and Vehicle-to-Everything (V2X) absolute and relative positioning.

12. The method of claim 1, ad-hoc network based positioning applications or ad-hoc direct positioning applications.

13. The method of claim 1, further comprising performing dynamic positioning by performing the method at each pair of vehicles in a network of moving vehicles or a mesh vehicle network.

14. The method of claim 1, further comprising using multiple-in, multiple-out antennas (MIMO antennas).

15. The method of claim 1, further comprising measuring round trip time, time difference of arrival, or angle of arrival.

16. The method of claim 1, further comprising performing multiple measurements of a single source of the received modulated carrier signal at multiple receivers, thereby increasing accuracy.

17. A method, comprising:

generating, at a first node, a baseband information signal by mixing a received modulated carrier signal with a local oscillator (LO) signal having an LO frequency, the modulated carrier signal being an in-phase signal and quadrature signal uncorrelated with each other and derived from different input data sets;

obtaining, at the first node, baseband signal samples of the baseband information signal having an in-phase signal sample and a quadrature signal sample;

determining, at the first node, a first observed frequency rotation based on an estimated correlation between the in-phase signal samples and the quadrature signal samples; and

,

generating, at the first node, a relative speed of the first node and a second node,

wherein the received modulated carrier signal is a quadrature-modulated signal with arbitrary orthogonal in-phase and quadrature signal components.

18. The method of claim 17, wherein observing the first observed frequency rotation is performed at the first node, and wherein observing a second observed frequency rotation is performed at the second node, and generating the relative speed is performed at the first node based on the second observed frequency rotation received from the second node.

19. The method of claim 17, further comprising generating the relative speed by dividing by two the sum of the first observed frequency rotation and the second observed frequency rotation.

20. The method of claim 17, wherein the first node and the second node are assumed to be in sync, and further comprising generating the relative speed by treating the first observed frequency rotation as a Doppler component.