Method and Device for Detection of Motion of the Surface of an Object

• US 20110006940A1
• Filed: 12/13/2007
• Published: 01/13/2011
• Est. Priority Date: 12/19/2006
• Status: Active Grant

• Current Assignee: Radarbolaget I Gavle AB
• Original Assignee: Radarbolaget I Gavle AB
• Inventors: Andersson, Daniel
• Granted Patent: US 8,106,812 B2
• Time in Patent Office: Days
• US Class Current: 342/22
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/288 phase modulated
• CPC Class Codes: G01S 13/534 based upon amplitude or phase shift resulting from movement of objects, with reference to the surrounding clutter echo signal, e.g. non coherent MTi, clutter referenced MTi, externally coherent MTi
• CPC Class Codes: G01S 13/888 through wall detection
• CPC Class Codes: G01S 7/024 using polarisation effects in waveguides H01P1/165; for aerials H01Q, e.g. H01Q15/22, H01Q15/24, H01Q19/195
• CPC Class Codes: G01S 7/2921 based on data belonging to one radar period
• CPC Class Codes: G01S 7/2923 based on data belonging to a number of consecutive radar periods

Abstract

The invention relates to a method for detection of motion of the surface of an object by means of a detection device, the object being stationary during a detection process, and situated in a space on the opposite side of a wall in relation to the detection device, and having a relative dielectric constant ∈r greater than 1.1. The method comprises steps of transmitting radar signals and receiving radar signals reflected by the object, and if a motion has been detected, in addition visualising the motion in a three-dimensional combined radar model and data model. The invention also relates to a detection device for carrying out the method.

Claims

1. A method for detection of motion of the surface (13) of an object (4) by means of a detection device (1), the object (4) being stationary during a detection process, and situated in a space (2) on the opposite side of a wall (3) in relation to the detection device (1), and having a relative dielectric constant ∈

_r greater than 1.1, the method is characterized by the steps of;

a) generating a data model of the object (4) and the above-mentioned space (2), which data model is stored in a central processing unit (10) comprised in the detection device (1),

b) transmitting radar signals in the form of radar pulses, the frequency components of which are distributed within the frequency range of 30 MHz-12.4 GHz,

c) receiving reflected radar signals generated at reflection points consisting of dielectric steps when the radar signals pass into and out of, respectively, the object (4),

d) comparing the received reflected radar signals with the transmitted radar signals in order to obtain correlation results, each of which communicates distances between two known positions (11a-c, 12) via said reflection points,

e) difference analyzing different correlation results obtained over time in order to detect a motion of a specific reflection point of the surface (13),

f) by means of difference analyses of correlation results belonging to at least three mutually separated sets of two known positions (11a-c, 12) unambiguously determining the location of the specific moved reflection point,

g) creating a radar model of the motion of the surface (13) of the object (4), and visualising the radar model in the above-mentioned data model.

2. Method according to claim 1, characterized by the step of revising the distance, communicated from correlation results, between two known positions (11a-c, 12) via said reflection points, considering the fact that the transmitted and received, respectively, radar signals propagate through the wall (3) that separates the detection device (1) and the object (4) and that has a relative dielectric constant ∈

_r greater than 1.1.

3. Method according to claim 1, characterized in that the radio waves transmitted in the form of pulses consist of a binary cyclic code sequence that has an unambiguously correlation result.

4. Method according to claim 1, characterized in that the radar signals are transmitted from at least three transmitters (11a-c) comprised in the detection device (1), and the reflected radar signals are received by one receiver (12) comprised in the detection device (1).

5. Method according to claim 1, characterized in that the radar signals are transmitted from one transmitter (11a-c) comprised in the detection device (1), and the reflected radar signals are received by at least three receivers (12) comprised in the detection device (1).

6. A detection device (1) for detection of motion of the surface (13) of an object (4), which is stationary during a detection process, and which is situated in a space (2) on the opposite side of a wall (3) in relation to said detection device (1), and which has a relative dielectric constant ∈

_r greater than 1.1, characterized in that the same comprises a central processing unit (10) in which a data model of the object and the above-mentioned space (2) is stored, means (11a-c) to transmit radar signals in the form of pulses, the frequency components of which are distributed within the frequency range of 30 MHz-12.4 GHz, means (12) to receive reflected radar signals generated at reflection points consisting of dielectric steps when the radar signals pass into and out of, respectively, the object (4), means to compare the reflected radar signals with the transmitted radar signals in order to obtain correlation results, each of which communicates a distance between two known positions (11a-c, 12) via said reflection points, means to difference analyze different correlation results obtained over time in order to detect a motion of at least one specific reflection point of the surface (13), means to unambiguously determine the location of the specific moved reflection point based on difference analyses of correlation results belonging to at least three mutually separated sets of two known positions (11a-c, 12), means to create a radar model of a detected motion of the surface (13) of the object (4), and means to visualise the radar model in the above-mentioned data model.

7. Detection device according to claim 6, characterized in that the same comprises at least three transmitters (11a-c) arranged to transmit the radar signals, and one receiver (12) arranged to receive the reflected radar signals.

8. Detection device according to claim 6, characterized in that the same comprises one transmitter (11a-c) arranged to transmit the radar signals, and at least three receivers (12) arranged to receive the reflected radar signals.