Indoor localization system with LTE code and carrier phase measurements and an IMU

Patent metadata

Field	Value
Publication number	US-11199630-B2
Application number	US-202017039843-A
Country	US
Kind code	B2
Filing date	Sep 30, 2020
Priority date	Oct 9, 2019
Publication date	Dec 14, 2021
Grant date	Dec 14, 2021

Abstract

Systems, device configurations and methods are provided for indoor localization for a navigator receiver based on broadband communication signals such as LTE. In one embodiment, an LTE-IMU framework determines receiver position indoors. Two different designs of LTE receivers are provided based on code phase and carrier phase determinations of the received signal. A base/navigator framework is presented to correct unknown clock biases of the LTE eNodeBs. In this framework, the base receiver is placed outdoors, has knowledge of its own position, and makes pseudorange measurements to eNodeBs in the environment whose positions are known. The base transmits these pseudoranges to the indoor navigating receiver, which is also making pseudorange measurements to the same eNodeBs. The navigating receiver differences the base and navigator pseudoranges. The navigator receiver is equipped with an extended Kalman filter (EKF) to fuse LTE and IMU measurements in a tightly-coupled fashion and estimate navigating receiver states.

First claim

What is claimed is:

1. A method for indoor localization for a navigator receiver, the method comprising:
receiving, by a device, a broadband communication signal;
processing, by the device, the broadband communication signal based on a receiver framework to estimate range of the device relative to a source of the broadband communication signal;
receiving, by the device, position and psuedorange measurement data from a base receiver;
receiving, by the device, inertial measurement unit (IMU) measurement data associated with the device;
determining, by the device, a position for the device based on estimated range of the device relative to the source, difference in psuedorange measurement data relative to the base receiver, and IMU measurement data, wherein a filter of the device determines position based on a state vector for the device, a clock state vector and IMU state vector; and
outputting, by the device, a navigation observable based on the position determined for the device.

2. The method of claim 1 , wherein the broadband communication signal is a cellular long term evolution (LTE) signal and wherein a cell-specific reference signal (CRS) of the broadband communication signal is tracked to estimate the range of the device.

3. The method of claim 1 , wherein the range estimate is determined based on a code based receiver framework including an operations to perform a coarse estimate of frame start time, estimation of channel impulse response, estimation of time of arrival and tracking symbol timing within a frame of a received signal.

4. The method of claim 1 , wherein the range estimate is determined based on a carrier-based receiver framework including operations to perform a coarse estimate of frame start time, estimation of doppler frequency of received signal, phase tracking of a cell-specific reference signal (CRS), and estimation of time of arrival.

5. The method of claim 1 , wherein receiving position and psuedorange measurement data from the base receiver includes receiving base position and base psuedorange measurements from a base device, wherein differences in psuedorange measurements are used by the device to remove clock bias from a received signal.

6. The method of claim 1 , wherein receiving the IMU measurement data includes receiving angular rate around a z-axis and two-dimensional specific forces along x and y axes.

7. The method of claim 1 , wherein determining position by the filter includes an operation to perform a discrete-time update of a clock state estimate for the device, wherein clock bias of the device is corrected.

8. The method of claim 1 , wherein determining position by the filter includes updating a state vector for the device based on an extended Kalman filter (EKF) operation, the EKF filter operation updating the state vector to account for clock bias and the IMU state vector, and wherein the EKF filter operation fuses IMU data with device measurements.

9. The method of claim 1 , wherein an extended Kalman filter (EKF) operation is performed to estimate a state vector from carrier phase measurements.

10. The method of claim 1 , wherein the navigation observable is at least one pseudorange measurement between a navigating receiver and a source of the broadband communication signal, wherein output of a navigation filter includes two-dimensional position and velocity of the device, and estimates of receiver clock bias and drift.

11. A device configured for indoor localization, the device comprising:
a receiver module configured to receive a broadband communication signal; and
a controller coupled to the receiver module, wherein the controller is configured to process the broadband communication signal based on a receiver framework to estimate range of the device relative to a source of the broadband communication signal;
receive position and psuedorange measurement data from a base receiver;
receive inertial measurement unit (IMU) measurement data associated with the device;
determine a position for the device based on estimated range of the device relative to the source, difference in psuedorange measurement data relative to the base receiver, and IMU measurement data, wherein a filter of the device determines position based on a state vector for the device, a clock state vector and IMU state vector; and
output a navigation observable based on the position determined for the device.

12. The device of claim 11 , wherein the broadband communication signal is a cellular long term evolution (LTE) signal and wherein a cell-specific reference signal (CRS) of the broadband communication signal is tracked to estimate the range of the device.

13. The device of claim 11 , wherein the range estimate is determined based on a code based receiver framework including an operations to perform a coarse estimate of frame start time, estimation of channel impulse response, estimation of time of arrival and tracking symbol timing within a frame of a received signal.

14. The device of claim 11 , wherein the range estimate is determined based on a carrier-based receiver framework including operations to perform a coarse estimate of frame start time, estimation of doppler frequency of received signal, phase tracking of a cell-specific reference signal (CRS), and estimation of time of arrival.

15. The device of claim 11 , wherein receiving position and psuedorange measurement data from the base receiver includes receiving base position and base psuedorange measurements from a base device, wherein differences in psuedorange measurements are used by the device to remove clock bias from a received signal.

16. The device of claim 11 , wherein receiving the IMU measurement data includes receiving angular rate around a z-axis and two-dimensional specific forces along x and y axes.

17. The device of claim 11 , wherein determining position by the filter includes an operation to perform a discrete-time update of a clock state estimate for the device, wherein clock bias of the device is corrected.

18. The device of claim 11 , wherein determining position by the filter includes updating a state vector for the device based on an extended Kalman filter (EKF) operation, the EKF filter operation updating the state vector to account for clock bias and the IMU state vector, and wherein the EKF filter operation fuses IMU data with device measurements.

19. The device of claim 11 , wherein an extended Kalman filter (EKF) operation is performed to estimate a state vector from carrier phase measurements.

20. The device of claim 11 , wherein the navigation observable is at least one pseudorange measurement between a navigating receiver and a source of the broadband communication signal, wherein output of a navigation filter includes two-dimensional position and velocity of the device, and estimates of receiver clock bias and drift.

Assignees

• Univ California

Inventors

• Kassas Zak
• Abdallah Ali
• Shamaei Kimia

Classifications

• H04W64/003

  locating network equipment · CPC title

• G01S5/02585

  at least one of the measurements being a non-radio measurement · CPC title

• H04L5/0048

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title

• H04W64/006

  with additional information processing, e.g. for direction or speed determination · CPC title

• H04W56/0005 Primary

  synchronizing of arrival of multiple uplinks · CPC title