EP2255218A1 - Détection d'une entité en mouvement - Google Patents

Détection d'une entité en mouvement

Info

Publication number
EP2255218A1
EP2255218A1 EP09747027A EP09747027A EP2255218A1 EP 2255218 A1 EP2255218 A1 EP 2255218A1 EP 09747027 A EP09747027 A EP 09747027A EP 09747027 A EP09747027 A EP 09747027A EP 2255218 A1 EP2255218 A1 EP 2255218A1
Authority
EP
European Patent Office
Prior art keywords
signal
location
reflections
stepped
antenna
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP09747027A
Other languages
German (de)
English (en)
Other versions
EP2255218A4 (fr
Inventor
Tim Dyson
Todd Mackey
James Mcneill
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
L3 Communications Cyterra Corp
Original Assignee
L3 Communications Cyterra Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by L3 Communications Cyterra Corp filed Critical L3 Communications Cyterra Corp
Publication of EP2255218A1 publication Critical patent/EP2255218A1/fr
Publication of EP2255218A4 publication Critical patent/EP2255218A4/fr
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/887—Radar or analogous systems specially adapted for specific applications for detection of concealed objects, e.g. contraband or weapons
    • G01S13/888—Radar or analogous systems specially adapted for specific applications for detection of concealed objects, e.g. contraband or weapons through wall detection
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/9021—SAR image post-processing techniques
    • G01S13/9029—SAR image post-processing techniques specially adapted for moving target detection within a single SAR image or within multiple SAR images taken at the same time
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
    • G01S7/415—Identification of targets based on measurements of movement associated with the target
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
    • H01Q9/26—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength
    • H01Q9/27—Spiral antennas

Definitions

  • This desc ⁇ ption relates to detecting moving entities, such as detecting the presence of a moving person concealed behind a wall m a building
  • Detection sensors may be used to determine the presence of objects when visual recognition is difficult Attorney Docket No 10897 0064 WO 1
  • a method for detecting entities based on movement includes transmitting a stepped-frequency radar signal from a first side of a wall to a second side of the wall and detecting reflections of the transmitted signal with a first antenna at a first detection location and with a second antenna at a second detection location
  • the method also includes generating data including information associated with frequency and phase shifts between the transmitted signal and the reflections of the transmitted signal detected with the first antenna at the first detection location and with the second antenna at the second detection location
  • the method further includes analyzing the generated data to determine information associated with a moving object located beyond the second side of the wall The analysis includes differentiating reflections of the transmitted signal detected with the first antenna at the first detection location from reflections of the transmitted signal detected with the second antenna at the second detection location
  • the second detection location can be spaced along at least a first axis from the first detection location
  • the method can also include detecting the reflections of the transmitted signal with a third antenna at a third detection location
  • the third detection location can be spaced along at least a second axis from the first or second detection locations and the second axis can be perpendicular to the first axis
  • generating the data can include generating data associated with frequency and phase shifts between the transmitted signal and the reflections of the transmitted signal detected with the first, second, and third antennas
  • Determining the information associated with a moving object can include analyzing the data associated with the frequency shifts to identify a presence of the moving object
  • Differentiating the reflections of the transmitted signal can include using differences between the phase shift of reflections as detected with the first, second, and third antennas to determine a location of the moving object defined by multiple spatial dimensions
  • the method can include rendering, on a display screen, an indication of the Attorney Docket No 10897 0064WO1 determined location of the identified moving object relative to location of the display screen in the multiple spatial dimensions
  • transmitting the stepped-frequency radar signal can include transmitting a first stepped-frequency radar signal at the first side of the wall to the second side of the wall and concurrently transmitting a second stepped-frequency radar signal at the first side of a wall to the second side of the wall
  • Transmitting the first stepped-frequency radar signal can include transmitting the first stepped- frequency radar signal at a first transmit location and concurrently transmitting the second stepped-frequency radar signal can include concurrently transmitting the second stepped-frequency radar signal at a second transmit location
  • the method can include differentiating the reflections of the first transmitted signal transmitted at the first transmit location with reflections of the second transmitted signal transmitted at the second transmit location
  • the method can include analyzing the data from the differentiated reflections to account for differences between the data associated with the phase shifts of the first and second transmitted signals which results from the spatial difference between the first and second transmit locations
  • transmitting the stepped-frequency radar signal can include beginning transmission of the stepped-frequency radar signal with a system at a first system location and moving the system during transmission of the stepped-frequency radar signal from the first system location to a second system location
  • Detecting the reflections of the transmitted signal can include detecting reflections of the transmitted signal during the movement of the system from the first system location to the second system location
  • Analyzing the generated data can include determining the information associated with the moving object located beyond the second side of the wall based upon the reflections detected du ⁇ ng the movement of the system from the first system location to the second system location
  • the method can include determining system motion as reflections of the transmitted signal are detected dunng the movement of the system from the first system location to the second system location
  • Generating the data can include generating data for detected reflections which includes information associated with frequency and phase shifts and associated with a corresponding system motion as Attorney Docket No 10897-0064WO1 determined when the reflection was detected
  • Analyzing the generated data can include generating a synthetic aperture radar image using the data including information associated with frequency and phase shifts and associated with a corresponding system motion
  • Determining the system motion as reflections of the transmitted signal are detected dunng the movement of the system can include sampling output of an mertial sensor within the system
  • Generating the data can include generating a packet of data for reflections received at each of multiple system locations between the first and second system locations, each packet including the information associated with frequency and phase shifts, and output of the sampled mertial sensor at the time the reflection was detected
  • the method can also include identifying a transmit-to-receive leakage signal resulting from the transmission of the stepped-frequency radar signal, generating a cancellation waveform configured to remove effects of the identified transmit-to- receive leakage signal, and using the generated cancellation waveform to remove effects of transmit-to-receive leakage signal of subsequent transmissions Further, the method can include, after transmitting the stepped-frequency radar signal, determining the stepped-frequency radar signal should be altered, and transmitting an altered stepped-frequency radar signal based upon the determination that the stepped- frequency radar signal should be altered The method can additionally include generating the altered stepped-frequency radar signal, the altered stepped-frequency radar signal having one or more of the transmitted frequencies removed The method can further include generating the altered stepped-frequency radar signal, the altered stepped-frequency radar signal having the order of the transmitted frequencies changed
  • the first antenna can be a forward looking antenna and the second antenna can be a backwards looking antenna
  • some aspects include a system for detecting entities based on movement
  • the system includes transmission circuitry configured to enable transmission of a stepped-frequency radar signal
  • the system also includes a first antenna configured to detect reflections of the transmitted signal at a first detection location of the system and a second antenna configured to detect reflections of the transmitted signal at a second detection location of the system
  • the system further Attorney Docket No 10897-0064WO 1 includes receiving circuitry configured to receive the detected reflections from the first and second antennas and to generate data including information associated with frequency and phase shifts between the transmitted signal and the reflections of the transmitted signal detected with the first antenna at the first detection location of the system and with the second antenna at the second detection location of the system
  • the system additionally includes a processor configured to receive the generated data from the receiving circuitry and to analyze the generated data to determine information associated with a moving object located at a side of a wall opposite to the system The analysis includes differentiating reflections of the transmitted signal detected with the first antenna at the first detection location of the system from reflections of the transmitted signal detected
  • the receiving circuitry can be a part of the processor
  • the second detection location of the system can be spaced along at least a first axis from the first detection location of the system
  • the system can include a third antenna configured to detect reflections of the transmitted signal at a third detection location of the system
  • the third detection location of the system can be spaced along at least a second axis from the first or second detection locations of the system
  • the second axis can be perpendicular to the first axis
  • the receiving circuitry can be configured to receive the detected reflections from the third antenna and to generate data associated with frequency and phase shifts between the transmitted signal and the reflections of the transmitted signal detected with the first, second, and third antennas
  • the processor can be configured to analyze the data associated with the frequency shifts to identify a presence of the moving object
  • the processor can be configured to use differences between the phase shift of reflections as detected with the first, second, and third antennas to determine a location of the moving object defined by multiple spatial dimensions
  • the processor can be configured to enable rendenng, on Attorney Docket No 10S97 0064WO1 a display screen, of an indication of the determined location of the identified moving object relative to the system in the multiple spatial dimensions
  • the transmission circuitry can be configured to enable transmission of a first stepped-frequency radar signal and a second stepped-frequency radar signal concurrently
  • the system can also include a first transmit antenna configured to transmit at a first transmit location of the system and a second transmit antenna configured to transmit at a second transmit location of the system
  • the transmission circuitry can be configured to enable the concurrent transmission of the first stepped-frequency radar signal with the first transmit antenna and the second stepped-frequency signal with the second transmit antenna
  • the receiving circuitry can be configured to differentiate reflections of the first transmitted signal transmitted at the first transmit location of the system with reflections of the second transmitted signal transmitted at the second transmit location of the system
  • the processor can be configured to account for differences between the data associated with the phase shifts of the first and second transmitted signals which results from the spatial difference between the first and second transmit locations of the system
  • the transmission circuitry can be configured to enable the transmission of the stepped-frequency radar signal to begin at a first system location and to continue during movement of the system from the first system location to a second system location
  • the receiving circuitry can be configured to receive the detected reflections of the transmitted signal du ⁇ ng the movement of the system from the first system location to the second system location
  • the processor can be configured to determine the information associated with the moving object located at the side of the wall opposite to the system based upon the reflections detected du ⁇ ng the movement of the system from the first system location to the second system location
  • the system can include a motion sensor configured to determine system motion as reflections of the transmitted signal are detected du ⁇ ng the movement of the system from the first system location to the second system location
  • the receiving circuitry can be configured to generate data for detected reflections Attorney Docket No 10897 0064WO1 which includes information associated with frequency and phase shifts and information associated with a corresponding system motion as determined by the motion sensor when the reflection was detected
  • the processor can be configured to generate a synthetic aperture radar image using the data including information associated with frequency and phase shifts and information associated with a corresponding system motion
  • the motion sensor can be an mertial sensor To generate data for detected reflections which includes a corresponding system motion, the receiving circuitry can be configured to sample output of the inertial sensor and to generate a packet of data for reflections received at multiple system locations between the first and second system locations, each packet including the information associated with frequency and phase shifts and output of the sampled mertial sensor at the time the reflection was detected
  • the processor can be configured to identify a transmit-to-receive leakage signal resulting from the transmission of the stepped-frequency radar signal, generate a cancellation waveform configured to remove effects of the identified transmit-to-receive leakage signal, and use the generated cancellation waveform to remove effects of transmit-to-receive leakage signal of subsequent transmissions
  • the processor can be configured to, after the transmission of the stepped-frequency radar signal, determine the stepped-frequency radar signal should be altered, and enable the transmission circuitry to transmit an altered stepped-frequency radar signal based upon the determination that the stepped-frequency radar signal should be altered
  • the processor can be configured to enable generation of the altered stepped-frequency radar signal, the altered stepped-frequency radar signal having one or more of the transmitted frequencies removed
  • the processor can be configured to enable generation of the altered stepped-frequency radar signal, the altered stepped- frequency radar signal having the order of the transmitted frequencies changed
  • the first antenna can be a forward looking antenna and the second antenna can be a backwards looking antenna
  • the first antenna can be a transceiver and, to enable transmission of the stepped-frequency radar signal, the transmission circuitry can be configured to enable transmission of the stepped-frequency radar signal with the first antenna Attorney Docket No 10897 0064WO1
  • some aspects include a system for detecting entities based on movement
  • the system includes transmission circuitry configured to enable transmission of a stepped-frequency radar signal
  • the system also includes a first antenna configured to detect reflections of the transmitted signal at a first detection location of the system and a second antenna configured to detect reflections of the transmitted signal at a second detection location of the system
  • the system also includes receiving circuitry configured to receive the detected reflections from the first and second antennas and to generate data including information associated with frequency and phase shifts between the transmitted signal and the reflections of the transmitted signal detected with the first antenna at the first detection location of the system and with the second antenna at the second detection location of the system
  • the system further includes processing means to analyze the generated data to determine information associated with a moving object located at a side of a wall opposite to the system The analysis includes differentiating reflections of the transmitted signal detected with the first antenna at the first detection location of the system from reflections of the transmitted signal detected with the second antenna at the second detection location of the system
  • Fig IA is a diagram illustrating use of a scanning device for detecting moving entities
  • Fig IB is a block diagram of a stepped-frequency scanning device configured to detect moving entities
  • Figs 2 A and 2B are perspective views of an antenna design for the device of Fig IB
  • Fig 3 is a diagram of an example conversion circuit in a scanning device
  • Fig 4A is a flow chart of an example of a process to detect moving entities using a transmitted stepped-frequency signal with a scanning device Attorney Docket No 10897 0064WO1
  • Fig 4B is a flow chart of an example of a process to detect moving entities including alternativeng transmitted waveforms used by a scanning device
  • Fig 5 A is a diagram illustrating use of mterferomet ⁇ c measurement with a scanning device
  • Fig 5B is a flow chart of an example of a process to detect moving entities using interferometnc measurement with a scanning device
  • Fig 6 A is a diagram illustrating use of multi-static motion detection with a scanning device
  • Fig 6B is a flow chart of an example of a process to detect moving entities o using multi-static motion detection with a scanning device
  • Fig 7 is a diagram illustrating use of transceivers to conduct interferometnc measurement and multi-static motion detection with a scanning device
  • Fig 8 A is a diagram illustrating use of synthetic aperture radar imaging with a scanning device 5
  • Fig 8B is a flow chart of an example of a process to detect moving entities using synthetic aperture radar imaging with a scanning device
  • Fig 9 A is a flow chart of an example of a process to analyze data associated with frequency and phase shifts generated by a scanning device
  • Fig 9B is a flow chart of an example of a process to cancel transmit-to-receive0 leakage signal with a scanning device
  • Fig 9C is a flow chart of an example of a process to compensate for motion occurring during operation of a scanning device
  • Fig 9D is a flow chart of an example of a process to compensate for motion occurring during operation of a scanning device using adaptive processing
  • Fig 1 OA is a picture of a handheld stepped-frequency scanning device relative to a semi-automatic weapon ammo pouch
  • Fig 1 OB is a picture of a handheld stepped-frequency scanning device in a Attorney Docket No 10897-0064WO 1
  • Fig 1 IA is a picture illustrating battery access in a handheld stepped- frequency scanning device
  • Fig HB is a graph illustrating power discharge characteristics in a handheld stepped-frequency scanning device
  • Fig 12A is a picture illustrating recessed light emitting diodes in a handheld stepped-frequency scanning device
  • Fig 12B is a picture illustrating operational controls of a handheld stepped- frequency scanning device
  • a device In order to detect the presence of entities through movement when visual detection is blocked (e g , by a wall), a device, such as a handheld scanner, includes a stepped-frequency radar transmitter
  • the transmitter emits a radar based signal that includes different frequencies
  • the emitted signal strikes objects and is partially reflected
  • the reflected signal may be affected by environmental characte ⁇ sites (e g , movement of an object or entity or distance to the object or entity)
  • environmental characte ⁇ sites e g , movement of an object or entity or distance to the object or entity
  • signals reflected from the object will exhibit a frequency shift (i e , a Doppler shift) that may be observed and processed by the device
  • the distance a signal travels before or after being partially reflected affects the phase of the reflected signal at the receiver
  • Va ⁇ ous processing methodologies and hardware configurations can be used by the device to analyze characteristics of reflected signal for useful information
  • processing information received from multiple receives can be used to determine a location in 2 or 3 spatial dimensions of detected movement
  • detecting differing rates of movement may require separate processing algorithms and/or separate characte ⁇ stics of the transmitted signal
  • a shorter duration (e g , a few seconds) of signal transmission at a set of frequencies may be transmitted to detect fast moving objects, such as an individual running while a longer duration (e g , less than 10 seconds) signal transmission may Attorney Docket No 10897-0064WO1 be employed to detect slower moving objects, such as the chest cavity of an individual breathing
  • the device may be used to aid in military or search and rescue missions For example, soldiers may use the device to detect the presence of unknown individuals that may be hiding behind walls A soldier may activate the device while aiming the transmitter such that the signal is pointed at a closed door The signal may penetrate walls and doors, and partially reflect when striking an individual (e g , an enemy soldier) The reflected portion of the signal may exhibit a frequency shift detectable by the device at multiple receivers The device receives and processes the reflected signal from the receivers, and may determine a presence in three spatial dimensions of one or more entities Also, the device may be used to detect the presence of individuals bu ⁇ ed in piles of rubble based on subtle movement, such as breathing
  • Fig IA shows a diagram 100 illustrating use of a scanning device for detecting moving entities
  • a user 105 holds an activated handheld stepped-frequency sensor device 110, which transmits stepped-frequency radar signals
  • the device 110 includes several forward looking antennas 114 and a backward looking antenna 116 (shown as arrows) This configuration is one example, various implementations of the device 110 and its arrangement of antennas are discussed in Figs 5A-7 Also, a single transmitted signal from the device 110 is described for simplicity, although multiple signals can be transmitted as discussed m Figs 6A-7
  • the device 110 may differentiate between signals received from the forward looking antennas 114 and those received from the backward looking antenna 116 to determine information associated with the location of detected movement (e g , whether the movement occurs in front of or behind the device)
  • the device 110 has been operated to transmit a signal either with one of more of the antennas as transceivers or with a separate transmitter
  • the signal (not shown) propagates outwards, st ⁇ kes objects, and is reflected 115A, 120A, 125A, 130A, and 135A
  • the reflected signal exhibits a frequency shift proportional to the magnitude of the object's movement towards or away from the device Attorney Docket No 10897 0064WO1
  • the signal may penetrate a wall 118 and be partially reflected by a running individual 115, a sitting individual 120, a spinning ceiling fan 125, and a stationary chair 130 on the opposite side of the wall
  • the signal also is partially reflected by a nearby stationary chair 135 that is on the same side of the wall 118 as 5 the user 105
  • the signal 120A reflected by the sitting individual 120 exhibits a small frequency shift due to the breathing movement of the individual's chest cavity
  • the signal 115A reflected by the running individual 115 exhibits a larger frequency shift than the partially reflected signal 120A from the sitting individual 120, with this frequency shift being due to the more pronounced movement of the body of the 10 running individual 115
  • the signal 125A reflected by the spinning ceiling fan 125 exhibits a frequency shift that is characte ⁇ stic of a repeated mechanical movement
  • the signals 130A and 135A that are reflected by the stationary chair 130 and the nearby stationary chair 135 exhibit no frequency shift
  • the device 110 receives and processes the frequency and phase information 15 from the partially-reflected signals 115A, 120A, 125A, 130A, and 135A
  • the signals may be received using a single antenna or using forward and backward looking antennas
  • the device 110 may calibrate against data associated with partially-reflected signals that exhibit no frequency shift 130A and 135 A or that exhibit only a frequency shift due to mechanically repeated movement 20 125
  • the processed data indicates movement reflective of both breathing and running
  • the device 110 provides indications of detected moving objects by lighting separate lights or providing other types of visual indicators
  • the device 110 can provide the results of the scan on a display screen 119 along with various information determined by 25 processing
  • the device uses three forward looking antennas to determine the location of objects m three spatial dimensions (as discussed in Figs 5A-5B) and provides a visual display of the relative location of two detected moving objects
  • reflected signal from the running individual 115, the sitting individual 120, 30 the spinning ceiling fan 125, and the stationary chairs 130 and 135 have all indicated the existence of objects, only two are shown on the display screen 119
  • the device 110 has removed the fully stationary objects (e g , the chairs 130 and 135) and the objects exhibiting characteristics of repetitious mechanical movement (e g , spinning ceiling fan 125) from consideration
  • processing techniques of the device 110 have determined the sitting individual 120 to be exhibiting movement indicative of a stationary person (e g , only subtle breathing movement) and the running individual 115 to be exhibiting movement indicative of an active person Therefore, of the detected objects, only the two individuals are represented on the display screen 119
  • the running individual 115 is represented on the display screen with a larger, more pronounced indication 119a to signify the significant level of movement whereas the sitting individual 120 is represented on the display screen with a smaller, less pronounced indication 119b to signify the less significant movement
  • Other implementations may show (or include options to show) all detected objects or a subset thereof (e g , show objects with repeated mechanical movement, show stationary objects, show any object detected that is between a detected moving object and the device 110)
  • Fig IB is a block diagram of a stepped-frequency scanning device 150 configured to detect moving entities
  • the device 150 includes antennas 155 and 160 for transmitting and receiving a stepped-frequency radio frequency signal (an "RF signal") to detect moving entities
  • the device 150 is shown as a bistatic radar, in that there are separate antennas for transmitting and receiving the RF signal
  • a transmit antenna 155 is connected to a radar transmitter and transmits an RF signal toward a target
  • a receive antenna 160 is connected to a radar receiver and receives a portion of the RF signal that is reflected by the target
  • the device 150 may be a monostatic radar that uses a single antenna as a transceiver to both transmit and receive the RF signal
  • vanous implementations may use multiple transmit antennas 155 and/or multiple receiving antennas 160 Attorney Docket No 10897 0064WO1
  • the transmit antenna 155 is connected to a radar transmitter 165 that transmits an RF signal toward a target
  • Implementations using more than one concurrent transmission may use one or more transmit antennas 155 which can be coupled to either a single shared/multiplexed radar transmitter 165 or multiple dedicated radar transmitters 165
  • the transmitted RF signal can include frequencies that cover a bandwidth in increments of frequency steps
  • the signal may include a nominal frequency operating with a center frequency in the UHF, L, S or X bands
  • the receive antenna 160 is connected to a radar receiver 170 and receives the reflected RF signal from the target
  • the receive antenna 160 is discussed in terms of the implementation including a single antenna Nevertheless, the receive antenna 160 may represent two or more antennas as shown by the forward looking antennas 114 of Fig IA Implementations employing multiple antennas may each have a dedicated receiver which is shared or otherwise multiplexed, or may include multiple dedicated receivers
  • the receiver 170 is coupled to a signal processor 175 that processes received RF signals from the receiving antenna 160
  • the signal processor 175 is coupled to a display 180 and a timing and control module 185
  • the display 180 provides audible and/or visual information or alerts of objects detected by the device, such as those described with the display screen 119 of Fig 1 A
  • the timing and control module 185 may be connected to the transmitter 165, the receiver 170, the signal processor 175, and the display 180
  • the timing and control module provides signals, such as a clock signal and control signals, to the other components of the device 150 Implementations may employ detection processes for slow or fast movement that run in real-time on an embedded processor Implementations also may employ interference detection processes
  • the signal processor 175 can include an interferometer/interferometer processing
  • the interferometer can process received signal to enable location of entities or targets within a given environment
  • the interferometer also can provide simultaneous stationary object mapping capability hi particular, the interferometer Attorney Docket No 10897 0064WO1 may receive channel signals, use a low-pass filtered to provide stationary object mapping, and use a high-pass filter for moving target angle estimation
  • the device 150 also includes a motion sensor 190 which may include an internal mertial sensor and/or global positioning system (GPS) sensor or other location sensors Detection of moving and/or breathing targets dunng handheld and/or on-the-move operation of the device 150 is supported through use of the motion sensor's measurement and resulting compensation dunng processing
  • a motion sensor 190 which may include an internal mertial sensor and/or global positioning system (GPS) sensor or other location sensors Detection of moving and/or breathing targets dunng handheld and/or on-the-move operation of the device 150 is supported through use of the motion sensor's measurement and resulting compensation dunng processing
  • GPS global positioning system
  • an mertial measurement sensor with or without the use of a global positioning sensor, can be incorporated with the motion sensor 190 to provide sensor motion measurement, thereby supporting motion compensation processing to factor out device 150 motion (as discussed below)
  • adaptive processing of the radar return can be used by the motion sensor 190 and/or the signal processor 175 to estimate the sensor motion independent
  • Fig 2A illustrates an antenna design 200 employed in one implementation of the device of Fig IB
  • the design 200 employs separate transmit and receive antennas 205 and 210 to simplify the electronics, provide spatial separation and reduce very shallow reflections
  • the antennas 205 and 210 which may serve as particular implementations of the antennas 114 and 116 of Fig IB, may be placed in a housing 215, and a cover 220 may be placed over the antennas
  • the cover 220 may be made of a suitable radome material
  • Fig 2B further illustrates aspects of the design 200 discussed above with respect to Fig 2A
  • the design 200 employs a spiral antenna as the receive antenna 210 to permit significant size reduction
  • the spiral radiates efficiently when it has an outer circumference of at least one wavelength This means that the antenna needs a maximum diameter of about one-third wavelength
  • the upper frequency limit for Attorney Docket No 10897-0064WO 1 efficient spiral radiation is set by the size of the feed point attachments, and the lower frequency limit is set by the outer diameter of the spiral structure Within these limits, the spiral radiates efficiently in a frequency-independent manner
  • the input impedance and the radiation patterns may vary little over this frequency range
  • the receive antenna 210 may be constructed by etching a spiral pattern on a printed circuit board A planar, p ⁇ nted circuit, spiral antenna radiates perpendicularly to the plane
  • the previous desc ⁇ ption provides an example implementation of an antenna design
  • Other implementations may include different antennas, such as an endfire waveguide antenna
  • Such a configuration may be slightly larger than the spiral configuration
  • the endfire waveguide antenna reduces the measurement spot size, thus making a more precise position of a concealed object easier to locate
  • Other suitable types of wideband antennas may also be used
  • Fig 3 is a diagram of an example conversion circuit 300 in a scanning device
  • the circuit 300 can be used as portions of the transmitter 165 and receiver 170 of Fig IB
  • the circuit 300 includes a signal generator 310, a signal control 320, a transmission multiplexer 330, a receive multiplexer 340, and a mixer 350, which may be in the form of a quadrature demodulator
  • the circuit 300 one or more transmission signals are generated and transmitted through one or more transmit antennas Reflected portions of the transmitted signal are received through one or more receive antennas, which may optionally be the same antennas as the one or more transmit antennas
  • the received signal and the signal generated by the signal generator 310 are input to the mixer 350, which outputs an in-phase signal and an out- of-phase (quadrature) signal
  • the signal generator 310 generates a signal to be transmitted by the one or more transmit antennas
  • the signal generator 310 may include a phase lock loop synchronized by an oscillator
  • a temperature controlled crystal oscillator is used to synchronize a voltage controlled oscillator
  • the Attorney Docket No 10897-0064WO1 signal generated by the signal generator 310 may be input to a mixer 350 and to a signal control 320
  • the signal control 320 may amplify or otherwise condition the signal to enable transmission by the one or more transmit antennas
  • the signal control 320 inputs the signal to the one or more transmit antennas and to a
  • the signal control 320 includes one or more signal outputs, each dedicated to one of the one or more transmit antennas and coupled to the transmission multiplexer 330
  • the transmission multiplexer 330 enables sequential sampling of the one or more signal outputs of the signal control 320 to provide feedback of the transmission signal to the mixer 350
  • 10 330 may function as a single pole double throw (SPDT) switch for each of the signal outputs of the signal control 320
  • the one or more transmit antennas emit the transmission signal, which encounters objects in the environment Portions of the transmission signal may be reflected
  • the reflected portions, which may exhibit a frequency and phase shift, are 15 received by the one or more receive antennas
  • the receive multiplexer 340 enables sequential sampling, by the mixer 350, of the signal received by each of the one or more receive antennas
  • the receive multiplexer 340 may function as a SPDT switch for each of the signals received by the one or more receive antennas
  • Some implementations may use other mechanisms, such as a control system, in place of the transmission multiplexer 330 and the receive multiplexer 340
  • the one or more receive antennas are input directly to a mixer without a multiplexer
  • the mixer 350 receives the signal from the signal generator 310 at a first 25 input Based on the transmission multiplexer 330 and the receive multiplexer 340, either the transmission signal or the received signal is provided to the mixer 350 at a second input
  • the mixer 350 converts input signals to a form that is more easily processed, such as, for example, an in-phase and an out of phase component at a baseband frequency
  • the mixer 350 is a quadrature demodulator, though 30 other signal conversion systems may be used
  • the quadrature demodulator outputs "I" and "Q" data (referred to as IQ data) which can be sent to an analog-to-digital Attorney Docket No 10897-0064WO1
  • a single transmit antenna and a single receive antenna are each coupled to a switch rather than the transmission multiplexer 330 and the receive multiplexer 340
  • Fig 4A is a flow chart of an example of a process 400A to detect moving entities using a transmitted stepped-frequency signal with a scanning device
  • the process 400 A may be implemented with the device 150 ofFig IB or with other devices Also, the process 400A may be implemented in conjunction with the processes of Figs desc ⁇ bed below
  • the process 400A begins when a stepped-frequency signal is transmitted by a device (41 OA)
  • the stepped-frequency signal may be an RF radar signal including multiple frequencies and phases that are transmitted concurrently or consecutively
  • each transmission includes cycling through a frequency band such that multiple frequencies are transmitted Specifically, while cycling through the band, each frequency is transmitted for a pe ⁇ od of time, followed by the next frequency, until the bandwidth has been crossed
  • multiple frequencies may be sent, one after another, the transmitted and received signals are discussed here and elsewhere as a single signal to simplify discussion After transmission, the signal stnkes an object and is partially reflected
  • the multiple transmissions of the stepped frequency signal (410) may include use of multiple transmit antennas simultaneously to form a multi-static radar
  • the transmit antennas may be located on a single device or across multiple devices
  • the combined measurements of signals can be received from the multiple transmissions by one or more receivers and can be used in processing to reduce interference and enhance detection of movement or location thereof
  • the transmit frequencies of the antennas are made different to avoid mutual transmission-interference
  • the antennas can be networked (on a single Attorney Docket No 10897 0064WO 1 device or between multiple devices) such that their transmit times are coordinated and the subsequent pre-processed data from each antenna can be processed in a central location
  • the distances between antennas can be determined through static location survey or by using position measurement sensors
  • randomized frequency orde ⁇ ng and wide bandwidth of the transmissions may be utilized to disguise the coherent nature or minimize the effects of intentional or incidental jamming
  • various implementations utilize a stepped- frequency pulse in which certain pulse frequencies are omitted in processing to screen out radio frequency interference from surrounding incidental or intentional sources
  • a non-umformly spaced, monotomcally ordered, stepped-frequency waveform may be used
  • a non-monotomcally ordered stepped-frequency waveform or a frequency-hopped tonal waveform also may be used
  • the transmitted waveform frequency steps can be transmitted in an order dictated by a quadratic congruential sequence
  • Two or more antennas can be operated simultaneously using mutually orthogonal stepped-frequency transmit sequences, such as, for example Bellegardia Sequences or Quadratic Congruences
  • some implementations enhance the effective aperture of the radar by moving the transmitting antenna along a pre-determined or motion-sensed line segment using a synthetic aperture radar (SAR) imaging operation mode
  • the stepped-frequency signal is transmitted by the device (410A) while the device is linearly moved
  • the known movement is combined with the received reflections and taken into account during processing to form a SAR image
  • information provided by a device's mertial measurement and/or location sensors can be used to assist the user in providing a proper motion or by the processor in correcting for imperfections in the motion
  • the device detects the reflected portion of the signal (420A) This detection can be accomplished using a transceiver, a separate antenna, or multiple separate antennas (e g , a forward looking and backward looking antennas or multiple forward looking antennas) In one implementation, a single transceiver transmits the stepped- frequency signal and receives reflected portions therefrom
  • the detected signal Attorney Docket No 10897-0064WO1 includes a frequency that may have been altered by movement of the struck object and a phase that may be affected by the distance to the object
  • multiple antennas for detection to enable more specific determination as to the location of an object (or entity)
  • Using multiple antennas spaced at known distances and positioned to receive signals in a similar direction can enable a more accurate two or three dimensional identification of an entity
  • processing the measurements from two or more antennas, separated rn a ho ⁇ zontal direction may be conducted to provide an estimate of azimuth angle-of-ar ⁇ val
  • elevation angle-of-arnval estimation may be provided by processing measurements from two or more antennas that are separated m a vertical direction
  • Simultaneous azimuth and elevation interferometry can enable estimation of each target's location in three spatial dimensions
  • the device's existing receiver can be multiplexed between multiple receiving antennas and/or additional receivers can be added to the device to receive the signals from multiple antennas simultaneously
  • the device processes the reflected portions of the signal to generate data associated with frequency and phase shifts (430A)
  • the processing may identify information associated with frequency and phase shifts that may be indicative of the presence of moving objects or objects at a distance
  • the processing may include a calibration step to calibrate the data or processing steps based on conditions detected for a particular use of the device
  • Calibration may include removing or alte ⁇ ng parts of the signal indicative of clutter, repeated mechanical movement, signal leakage, or reflections near or behind the device
  • Processing may also include calibration of the analysis steps, such as integration time
  • leakage cancellation can be used in the calibration processing
  • vanous components of the transmit-to-receive leakage signal can be adaptively located and removed from the received signal Such components can generally be orders of magnitude higher than the highest reflected signal
  • Their cancellation can provide a reduced dynamic range of the subsequent signal data
  • Attorney Docket No 10897-0064WO1 also can suppress the range sidelobes of the leakage signal which otherwise may obscure lower
  • the device uses a motion and/or location sensor to calibrate information from the reflected portions of the signal du ⁇ ng or p ⁇ or to processing
  • motion or location information can be used to support motion compensation processing to factor out device motion
  • adaptive processing of the radar return can be used by the device to estimate device motion
  • Such adaptive processing can be employed by using the phase change of stationary scatte ⁇ ng present in the scene to estimate the sensor motion
  • the device analyzes the data to determine if the reflected portions of the signal are associated with moving objects or entities (440A)
  • the analysis of the data (440A) may include use of a short-time Fou ⁇ er Transform to estimate the Doppler shift of the return signals as one of multiple Fou ⁇ er Transformation integration times
  • the analysis may include using a low-pass filter to provide data for stationary object mapping and using a high-pass filter to provide data for moving target angle estimation
  • processing techniques such as Maximum Likelihood Method, Maximum Entropy Method, or Music Method, may offer
  • the process 400A can configure the transmitted waveform internal structure, bandwidth extent, and duration to better match and reveal certain target characteristics and fine-grained structure
  • small movements of machinery e g , clock mechanisms, slow speed rotating pumps
  • human motions e g , voluntary and involuntary facial movements and life sign processes such as breathing, heart beat and blood flow withm the arterial cavities
  • These targets when re-exammed with the properly designed transmitted waveform, can reveal their nature in the form of very small displacements over time that impart micro-Doppler structure on the returned signals
  • movement of 50-70 microns and less can be detected through adjustments to the transmit waveform characteristics and receiver processing algorithm parameters
  • Results of the analyzed data are then displayed (450A)
  • the results can be displayed using a series of indicators or lights
  • movement detected as significant e g , from a running individual
  • movement detected as less significant e g , from an individual sitting and breathing
  • a display screen is used to illustrate two or three dimension positions of movement with or without additional information about the movement
  • a visual display of the relative location of multiple detected moving objects can be shown as locations on a three dimensional graph or representation of a space
  • the significance or level of movement of the detected moving objects can be indicated by, for example, size, shape, color, or animation of the indications
  • the device can de ⁇ ve information of the area using information from the received reflections (e g , derive existence of stationary objects such as walls) or by loading preexisting data (e g , load a geographical map of an area or representation of Attorney Docket No 10897-0064WO1 the
  • the device is configured to determine the relative positions of other devices
  • the device can locate other devices by detecting a unique broadcast signature du ⁇ ng transmission (e g , a particular sequence of frequency steps) or by wireless network communications
  • individuals without a scanner may include other RF identification tags that can be similarly located and identified
  • the device can display the position of other located devices/individuals on the display screen by rendering a unique indication
  • such located other devices/individuals can be displayed with a first color indication while identified unknown moving objects can be displayed with a second color indication
  • This can enable a unit of soldiers to, for example, identify whether a target m another room is likely a non-threat (e g , a "friendly") or a threat (e g , a "hostile")
  • devices can be configured to share results of analysis with other nearby devices using wireless communication From this shared information, the device can display results computed from other devices For example, if a first device determines there is a moving object 3
  • the process 400A is an example implementation of a process to sense moving entities using, for example, a stepped-frequency scanning device Some implementations may include additional or alternative steps For example, processing and analyzing the data (430A and 440A) may be conducted together Attorney Docket No 10897 0064WO1
  • Fig 4B is a flow chart of an example of a process 400B to detect moving entities including alte ⁇ ng transmitted waveforms used by a scanning device
  • the process 400B may be implemented with the device 150 of Fig IB or other devices
  • the process 400B can be used along with or separate from the process 400A of Fig 4A
  • a device may be able to compensate for the effects of noise or interference, and may be able to avoid or overcome the presence of signal jamming
  • the device includes an mput option to randomize the waveform frequencies or to select alternative frequency stepping
  • the user can activate a manual alteration input (e g , a button on the device)
  • the device is t ⁇ ggered to adjust the transmission waveform used in subsequent transmission
  • a user may determine that alteration is needed prior to any transmission, such as, if the user suspects that an identifiable transmission may result in directed jamming
  • the device is configured to determine that the transmission waveform should be altered (410B) without additional user mput as a result of vanous conditions
  • the device can be configured to t ⁇ gger alteration of the transmission waveform in response to a determination of poor results during processing and analysis of data, such as, if saturation or degraded performance is detected (discussed below)
  • the device can be configured to determine that the transmission waveform should be altered (410B) in response to a determination that frequencies are jammed or otherwise have high levels of interference
  • the device detects signals present p ⁇ or to transmission (prior to each transmission or during device power on) If a frequency is Attorney Docket No 10897 0064WO1 found to be unavailable due to jamming or interference, the device alters the waveform to remove frequency steps in or near the unavailable frequency
  • the device proceeds to alter the transmission waveform (420B)
  • the alte ⁇ ng may include removing specific frequencies, changing the step pattern of the frequency steps, randomizing frequency steps, or otherwise generating a non-umformly spaced, monotomcally ordered stepped-frequency waveform
  • the alte ⁇ ng may include accessing a stored transmission waveform of a se ⁇ es of discrete stepped-frequencies for transmission, alternativeng one or more of the discrete stepped-frequencies or order thereof, and sto ⁇ ng the altered transmission waveform in permanent or temporary storage (e g , random access memory) for use du ⁇ ng subsequent transmission
  • permanent or temporary storage e g , random access memory
  • the altered waveform is transmitted by the device as a stepped- frequency signal (430B)
  • the frequency steps of the altered waveform can be transmitted in an order dictated by a quadratic congruential sequence
  • two or more transmit antennas can be operated simultaneously using mutually orthogonal stepped-frequency transmit sequences, such as, for example
  • Fig 5 A is a diagram 500A illustrating use of interferometnc measurement with a scanning device 502 A and Fig 5B is a flow chart of an example of a process 500B to detect moving entities using interferometnc measurement with the device 502 A
  • the desc ⁇ ption of Figs 5 A and 5B is directed to the use of multiple receiving antennas
  • the determined location of moving objects can be of greater specificity
  • a single receiving antenna generally enables determination of a linear distance between the device 502A and the object
  • using three receiving antennas can enable determination of a location in three spatial dimensions relative to the device 502A
  • the device 502A may be implemented as a part of the device 150 of Fig IB or other devices
  • the process 500B can be used along with or separate from the process 400A of Fig 4A Attorney Docket No 10897-0064 WO 1
  • the device 502 A transmits a stepped-frequency signal (51 OB)
  • the signal may be a stepped-frequency signal transmitted using a single transmit antenna 505A
  • the signal propagates outward from the device 502A and reaches a moving object 540A, where it is partially reflected
  • the reflected portions of the signal 5 propagate back to the device 502A with a frequency change proportional to the magnitude with which the moving object was moving towards or away from the device 502A
  • the phase changes with position while frequency remains constant
  • the reflected portions of the signal propagate past each of the first, second, and third receiving antennas 510A-530A
  • the reflected portions of the signal are detected by the first receiving antenna
  • the first receiving antenna 510A is at a first location, and the reflected portions of the signal exhibit a first phase relative to the first location The reflected portions of the signal are also detected by the second receiving antenna 520A of the device 502A (53OB) The second receiving antenna
  • the third receiving antenna 530A is at a third location which is spaced from the first and/or second locations
  • the first and second receiving antennas 510A and 520A 20 are separated along a first axis (e g , horizontally) to create a first mterferomet ⁇ c pair and the third receiving antenna 530A is separated from the first and/or second receiving antennas 510A and 520A along a second axis which is perpendicular to the first axis (e g , vertically) to create a second mterferomet ⁇ c pair
  • the back lobe of a rear facing antenna can be used in conjunction with the first and 25 second mterferomet ⁇ c pairs which are forward looking in the diagram 500A to provide additional interferometnc measurement capability to increase accuracy of angle of ar ⁇ val estimation
  • Different implementations can place the receiving antennas 510A-530A differently, such that they are separated by multiple dimensions
  • the detections (520B- 30 540B) can be conducted nearly simultaneously (i e , detection can be temporally separated only
  • the reflected portions are processed to generate data associated with frequency and phase shifts (550B) using, for example, the techniques desc ⁇ bed above with respect to element 430A of Fig 4A
  • the processed data is analyzed to determine location information of moving objects (560B)
  • the spatial locations 5 of the receiving antennas 510A-530A and the phase of the reflected portions as measured by the receiving antennas 51OA-53OA are taken into account to determine the physical position of the moving object 540A relative to the device 502A
  • the device 502 Auses the phase differences between reflected portions of the signal as received by the first and second receiving antennas 510A and
  • the device 502A processes the phase differences between reflected portions of the signal as received by the second and third receiving antennas 520A and 530A and the known physical
  • the device 502 A uses azimuth and elevation interferometry of the data to determine the physical location of the moving object 540A in three spatial dimensions
  • the device 502A displays a multidimensional representation indicating 20 the determined location information of the moving object 540A (570B) using, for example, the techniques desc ⁇ bed above with respect to element 450A of Fig 4A
  • Fig 6 A is a diagram 600A illustrating use of multi-static motion detection with a scanning device 602 A and Fig 6B is a flow chart of an example of a process 600B to detect moving entities using multi-static motion detection with the device
  • Figs 6 A and 6B are directed to the use of multiple signal transmissions By using multiple transmissions, more precise identification of movement and location thereof can be provided Moreover, the multiple transmissions can protect against degraded results due to jamming, interference, or noise Additionally, some implementations conduct the transmissions in a sequence to
  • the device 602 A may be implemented as Attorney Docket No 10897 0064WO1 a part of the device 150 of Fig IB or other devices
  • the process 600B can be used along with or separate from the process 400A of Fig 4A
  • the three transmit antennas 610A-630A are part of a single device 602 A
  • the transmissions occur on a single shared transmit antenna (not shown) to minimize device size and required components
  • dedicated transmit antennas can reduce circuit complexity and lower issues of interference
  • separate antennas may be needed for receipt of signals, and therefore may be utilized for separate transmission as well
  • first, second, third transmit antennas 610A-630A are used to transmit three signals Specifically, a first stepped-frequency signal is transmitted with the first transmit antenna 610A (610B), a second stepped-frequency signal is transmitted with the second transmit antenna (620B), and a third stepped-frequency signal is transmitted with the third transmit antenna (630B)
  • the transmissions of the three signals (610B-630B) can be conducted concurrently or spaced m time
  • the three transmit antennas 610A-630A can each be a transmit antenna of separate devices, rather than from a single device 602 A (as shown)
  • the transmissions of the three signals are all conducted concurrently
  • the transmit frequencies are made to be different to minimize interference and to facilitate distinguishing between the reflected portions of the signals
  • the transmit antennas 610A-630A can each transmit a particular frequency within a predetermined se ⁇ es of frequency steps Thereafter, each transmit antenna concurrently transmits the next respective frequency of the senes
  • the first transmission may be Fi for the first transmit antenna 610A, F 2 for the second transmit antenna 620A, and F 3 for the third transmit antenna 630A
  • the next transmission can follow as F 2 for the first transmit antenna 61 OA, F 3 for the second transmit antenna 620A, and Fi for the third transmit antenna 630A
  • the physical separation for the three transmit antennas 610A-630A Attorney Docket No 10897 0064WO1 can be used during subsequent processing and/or analysis to account for difference in propagation distance of signals
  • a particular device can be used to control transmission, detection, and processing
  • the devices can be networked together (using line or wireless communication) to control flow of information and commands
  • a first device of the multiple devices can direct other devices when and what frequency to transmit, similar to how the device 602A directs the three transmit antennas 610A-630A
  • the first device can also detect reflected portions of each signal and conduct processing and analysis of the signal transmitted by each of the multiple devices
  • the first device can receive position information of the other devices to be used du ⁇ ng processing and analysis Results of the processing can be communicated from the first device to each of the other devices, enabling the user of each device to perceive the results
  • Reflected portions of the first, second, and third signal are detected using a receiving antenna 605 A (640B) and the reflected portions are processed to generate data associated with frequency and phase shifts, using, for example, the techniques desc ⁇ bed above with respect to elements 420A and 430A of Fig 4A
  • the signal received by the receiving antenna 605 A can be filtered to separately extract the reflected portion of each transmission
  • the signal received by the receiving antenna 605A is filtered with an approp ⁇ ate filter to extract signals near each of frequencies Fi, F 2 , and F 3
  • the signal received by the receiving antenna 605A is sent to a number of filters equivalent to the number of transmission (in this example, 3 filters), where each filter extracts signal near a particular frequency
  • the signal received by the receiving antenna 605 A is sent to a single adjustable filter which is adjusted to extract signals near a
  • the processed data is analyzed to determine location information of moving objects (660B) If multiple transmit antennas are used (as shown in the diagram Attorney Docket No 10897 0064WO1
  • the device 602A takes into account the known distance between the transmit antennas to account for different propagation distances of transmitted signals
  • Implementations directed to concurrent transmissions can enable the determination of more precise identification of movement and its location Using, for example, three transmissions can provide three separate data snapshots of a given scene These snapshots may each have some differences due to signal noise, unwanted reflection, leakage, or other interference By averaging the three data sets, the effect of such interference is reduced Also, targeted or general signal jamming may be present on one, but not all, transmitted frequencies, resulting in very poor data The device can selectively discard data from one or more transmitted frequencies Therefore, the use of multi-static motion detection may overcome some effects of jamming
  • some implementations directed to one-at-a-time transmission enable a more rapid refreshing of data
  • the time required to complete the process 400A of Fig 4A can be too large to update a user of a quickly changing situation
  • data presented to the user can be updated more often If, for example, the process 400A requires one half of a second to complete and three separate transmissions are spaced at a half second, data can be refreshed at approximately 6 hertz (depending on processing speed and other parameters, the time required to complete the process 400A may be significantly different than one half of a second)
  • One-at-a-time refers to the start of transmission and does not preclude the possibility of an overlap between an ending of a first transmission and the start of a second transmission
  • the order of the elements of process 600B can be different than shown in Fig 6B
  • reflected portions of the first signal can be detected using the receiving antenna 605 A prior to the transmission of the second stepped-frequency signal with the second transmit antenna 620A
  • the device 602A displays a multidimensional representation indicating the determined location information of the moving object 640A (670B) using, for example, the techmques desc ⁇ bed above with respect to element 450A of Fig 4A Attorney Docket No 10897-0064WO1
  • Fig 7 is a diagram 700 illustrating use of transceivers to conduct mterferomet ⁇ c measurement and multi-static motion detection with a scanning device
  • the device 702 may be implemented as a part of the device 150 ofFig lB or other devices
  • the device 702 includes first, second, and third transceivers 710-730
  • Each transceiver is configured to both transmit and receive stepped-frequency signals and is spaced from the other transceivers Therefore, the device 702 is able to conduct multi-static motion detection as desc ⁇ bed in Fig 6B of a moving object 740 through transmission by the transceivers 710-730 and to conduct mterferometnc measurement as desc ⁇ bed in Fig 5B of the moving object 740 through signal receipt by the transceivers 710-730
  • the diagram 700 illustrates the deflected signals but not the three transmitted signals
  • the device 702 may use a mix of transceivers with transmit antennas or receive antennas
  • a device 702 configured to use mterferometnc measurement as desc ⁇ bed in Fig 5B without the need for multi-static motion detection may require three receive antennas but only one transmit antenna
  • the device 702 can include a transceiver antenna used for all transmission and as a first receive antenna and two spaced receive antennas used as second and third receive antennas in mterferometnc analysis
  • Fig 8A is a diagram 800A illustrating use of SAR imaging with a scanning device 802A and Fig 8B is a flow chart of an example of a process 800B to detect moving entities using SAR imaging with the device 802A SAR imaging artificially enhances the effective aperture of the receiving antenna of a device
  • SAR imaging artificially enhances the effective aperture of the receiving antenna of a device
  • the results data can correspond to the results obtain from a device with a receiving antenna spanning a meter
  • the device 802 A may be implemented as a part of the device 150 of Fig IB or other devices
  • the process 800B can be used along with or separate from the process 400A of Fig 4 A
  • a SAR operation mode of the device 802 A is activated (810B)
  • the activation may be as a result of input by a user to the device 802 A to select one of multiple operation modes
  • the device 802A includes an input option to specify that SAR will be used
  • the device Attorney Docket No 10897-0064WO 1
  • SAR operation is the standard mode of the device 802A, and powering on the device 802A activates SAR operation
  • Transmission of a stepped- frequency signal begins at a first location 810A 5 (820B)
  • the transmission can begin as a result of user input
  • the user may activate an input option (the same input option or another input option) to t ⁇ gger the start of transmission
  • the transmission may be t ⁇ ggered based upon movement of the device 802 A such as that detected from an internal motion sensor
  • activating the SAR operation mode (810B) initiates device 10 802A monitoring of movement When movement is deemed significant (e g , motion of at least 100 millimeters is detected), transmission of the signal begins (820B) Therefore, when ready, the user can ready the device 802A for SAR operation and begin the scan by beginning the motion of the device (as descnbed below)
  • the device 802 A is moved from the first location 81OA to a second location 15 820A while transmitting the stepped-frequency signal (83OB) and reflected portions of the signal are detected du ⁇ ng movement of the device from the first location 81 OA to the second location 820A (840B)
  • the movement can be a lateral movement created by the user to move the device 802 A from the first location 810A to the second location 820A Du ⁇ ng the movement, the device 802 A receives reflected portions of 20 the signal
  • the reflected portions of the signal may be received and used for subsequent processing along with an indication of where or when the signal was received
  • the device 802A can use time in conjunction with an assumed movement rate or can use measurements from an internal motion sensor to determine the location of the moving antenna at the time reflected portions are detected
  • an internal motion sensor is used to provide dynamic SAR scanning Specifically, the device 802A uses the start and stop of motion to trigger the start and end of transmission/detection Therefore, a user with ample room to obtain a large aperture can move the device across a longer distance while a user not able to move the device a full meter can nevertheless use space less
  • the processing can use techniques similar to those discussed in, for example, element 650B of Fig 6B
  • the reflected portions may be received and processed into discrete packets of data associated with frequency and phase shifts
  • the packets can be associated with a relative position in the movement Implementations with an internal motion sensor can use motion information to t ⁇ gger generation of packets at specific physical intervals and record the location of each packet based on sensed motion For example, in one implementation, a packet is recorded every half wavelength (e g , at approximately every 2 5 inches) across one foot of lateral device motion based upon internal motion sensing Implementations not employing motion sensors can be configured to assume movement of a particular speed for the purposes of packet location determination, and the user can be trained to move the device 802A at approximately the assumed speed
  • the processed data is analyzed to determine location information of moving objects (860B) and a multidimensional representation indicating the determined location information is displayed (870B), using, for example, the techniques described above with respect to elements 440A and 450A of Fig 4A
  • Fig 9 A is a flow chart of an example of a process 900A to analyze data associated with frequency and phase shifts generated by a scanning device
  • the process 900A is earned out with the device 150 of Fig IB and can be used to perform element 440A of Fig 4A, element 440B of Fig 4B, element 560B of Fig 5B, element 660B of Fig 6B, or element 860B of Fig 8B
  • the process 900A is desc ⁇ bed with respect to element 440A of Fig 4A
  • the process 900A receives processed IQ data that may be generated, for example, by element 430A of Fig 4A and with the circuit 300 of Fig 3
  • the process 900A involves multiple signal processing paths, degraded performance processing (910A), overt movement processing (925A), and subtle movement processing (975 A)
  • degraded performance processing (910A) overt movement processing (925A)
  • subtle movement processing (975 A)
  • the signal processing paths are discussed separately, though the different types of processing may be concurrently earned out on the same input signals
  • paths shown are examples only Other implementations may conduct processing along a single path configured to process Attorney Docket No 10897-0064WO1 overt or subtle movement
  • Each processing path may be associated with a specific type of result displayed from the output generator (965A)
  • phase and/or frequency data for each transmitted frequency is first used to develop a current picture of an environment, and is then compared against further phase and frequency data to determine differences
  • the process 900A incorporates coherent integration gam and robust detection algorithms, to provide enhanced range of movement detection, higher probability of detection (Pd), and a lower probability of false alarm (Pfa)
  • the process 900A begins when IQ data is input to be processed (905A)
  • the input IQ data can be the output of the mixer 350 of the circuit 300 of Fig 3
  • the IQ data is generated using a single transmit antenna and a single receive antenna
  • the IQ data is generated using multiple transmit antennas for mterferomet ⁇ c processing and/or multiple receive antennas for multi-static processing Accordingly, the process 900A can be used to implement portions of the processes 500B of Fig 5B and 600B of Fig 6B
  • the user inputs one or more commands associated with one or more of overt movement processing (925A), subtle movement processing (975A), or both
  • overt movement processing 925A
  • subtle movement processing 975A
  • a user wishing to target only subtly moving objects e g , the cardio-pulmonary function of an individual sleeping or in a coma
  • a single command may be pressed, which may, depending on the reflected signal, t ⁇ gger overt moving processing (925A), subtle movement processing (975A), or both IQ data is input to a calibrator (935A) and to a saturation detector (915A)
  • the saturation detector (915A) sends data to a degraded performance detector (920A), which monitors for situations including detection of A/D converter saturations or unusually high signal levels that may a ⁇ se from the transmitted signal reflecting off metal objects buried withm or behind walls, detection of significant increases in the noise floor resulting from intentional or unintentional jamming, and detection of significant signal energy across all range cells associated with excessive movement of Attorney Docket No 10897-0064WO1 the antenna If such situations are detected, the degraded performance detector (920A) can determine that the transmission waveform of subsequent transmission should be altered according to element 410B of Fig 4B Also, data from the degraded performance detector (920B) can be sent to the output generator (965A) to trigger a visual indication or an alert to specify the detection of a degraded signal The alert may signify to the user that processing results may be less reliable Degraded performance processing (910A) need not interrupt other processing
  • the IQ data may first be sent through the calibrator (935A)
  • Calibration can be used to minimize the effects of non-ideal transceiver hardware, such as transmit-to-receive signal leakage, unwanted device movement, interference, or other adverse effects upon the IQ data or collection thereof Target detection performance may be improved as a result of cleaner range and Doppler profiles
  • Calibration can provide for adjustment of the collection of data, by, for example tnggenng the determination that the transmission waveform of subsequent transmission should be altered according to element 410B of Fig 4B
  • Calibration can also provide for adjustment of collected data, to for example, compensate for direct-current (DC) offset errors, IQ gam and phase imbalance, and gam and phase fluctuation across frequency which may be caused, for example, by transmit-to-receive signal leakage or unwanted device movement
  • DC direct-current
  • IQ gam and phase imbalance gam and phase fluctuation across frequency which may be caused, for example, by transmit-to-receive signal leakage or unwanted device movement
  • the overt movement processing (925A) can be optimized for rapid detection of moving personnel Processing delays associated with filtering and coherent integration can be short, enabling quicker display/alert of indications of detected movement, for example, within less than a second of the event in some implementations
  • the overt movement processing (925A) can begin with the data output from the calibrator (935A) input to the moving target indication (MTI) filter Attorney Docket No 10897-0064WO1
  • Flagged returns from the MTI filer (940A) can be used by the output generator (965A) to identify flagged objects accordingly
  • objects flagged as stationary are presented with a characteristic (e g , a color or uniquely shaped icon) which differs from objects not flagged as stationary and object flagged as likely repeated mechanical movement are similarly presented with a different charactenstic
  • Each transmit frequency may be processed by a separate filter having a bandpass response that passes signals from separate target velocities
  • Separate filters may enable detection of short duration movements from the arms and legs of stationary personnel as well as the detection of the main body movement, such as walking and running
  • the data output from the MTI filter (940A) is input to the high range resolution (HRR) processor (945A)
  • HRR high range resolution
  • the HRR process (645A) uses an inverse fast fou ⁇ er transform (IFFT) to transform the ensemble of returns from the received signal to HRR profiles
  • IFFT inverse fast fou ⁇ er transform
  • other transforms may be used
  • the HRR process (945A) results may be input to the degraded performance detector (920) as well as the Doppler processor (950A)
  • the Doppler processor (950A) may provide additional coherent integration gain to further improve the signal-to-noise ratio
  • a region detector (955A) selects a Doppler bin with amplitude regions from range resolution cells
  • the region amplitudes are passed on to a Range constant false alarm rate processor (CFAR) (960A)
  • the Range CFAR (960A) is a cell-averaging constant false alarm rate (CA-CFAR) detector and operates along the HRR range cells output from the region detector (955A)
  • the range cells are compared to the surrounding cells A detection may be sent to the output generator (965 A) if calculated parameters of the cell under test are greater than a predetermined amount
  • Subtle movement processing (975A) is optimized for detection of stationary personnel, such as individuals whose only significant movement is that caused by respiratory and/or cardiac function
  • Subtle movement processing (915A) includes the Attorney Docket No 10897 0064WO1 calibrator (935A), the HRR processor (945A) and the Doppler processor (950A), but with longer integration times A longer integration time provides fractional-hertz Doppler resolution to resolve the earner modulation sidebands associated with breathing
  • the HRR processor (945 A) can be used directly on the calibrated radar data, bypassing the MTI filters that may otherwise remove the respiration sidebands
  • the output of the Doppler processor (950A) is sent to a Doppler CFAR processor (980A)
  • the Doppler CFAR processor (980A) may be applied across the Doppler processor (95OA) output to identify portions of the spectrum that are significantly above the noise floor Values selected by the Doppler CFAR processor (980A) may be input to the spectrum variance estimator (985A) where the power-weighted second-moment of the spectrum is determined If the calculated spectrum variance is within limits typical of respiration, the output generator (965A) may declare detection of subtle movement
  • the output generator (965A) receives the results of the analysis of the IQ data from one or more of the overt movement processing (925A), subtle movement processing (975A), and the degraded performance processing (91 OA) For example, IQ data may be analyzed according to each processing path, generating multiple sets of results
  • the output generator (965A) may give pno ⁇ ty, such that, if the same object is identified as overt and subtle movement, the output generator (965A) considers the object overtly moving
  • the output generator (965A) may perform additional clean-up of the detection map, including, for example, removal of detections beyond a range, and encoding the detection as either near or far
  • the output generator (965A) constructs a graphic user interface (GUI) to render the results for display to the user
  • GUI graphic user interface
  • the output generator (965A) can output results of signal processing to a SAR processor (990A)
  • the SAR processor (990A) is used as a feedback loop in implementing portions of the process 800B of Fig 8B Specifically, the SAR processor (990A) receives the output of the output generator (965A) and outputs SAR Attorney Docket No 10897-0064WO1 processing data as further IQ data for subsequent processing using the process 900A to provide a radar image with a synthetic aperture
  • the above process 900A is an example and other processing techniques could be used along with or separate from elements of the process 900A
  • alternate techniques discussed in Fig 4A such as Maximum Likelihood Method
  • Maximum Entropy Method, or Music Method may offer greater resolution for micro- Doppler detection using shorter observation times
  • methods such as Singular Spectrum Analysis (SSA) and Higher-order statistics based techniques (e g , Bispectral Analysis) can also be used to better resolve very closely spaced independent target returns than is possible with direct Fourier methods
  • SSA Singular Spectrum Analysis
  • Higher-order statistics based techniques e g , Bispectral Analysis
  • other methods that focus on reducing the computational cost relative to the FFT methods can be used to create the frequency (Doppler) spectrum, such as, Discrete Cosine Transform, Fast Hartley Transform, and Walsh-Hadamard Transform
  • Fig 9B is a flow chart of an example of a process 900B to cancel transmit-to- receive leakage signal with a scanning device
  • This processing approach can be used to adaptively locate and remove various components of the transmit-to-receive leakage signal, which generally are orders of magnitude higher in amplitude then the highest reflected portions of signal intended to be detected
  • This cancellation can reduce the dynamic range of the signal data and also can suppress the range sidelobes of the leakage signal which otherwise may obscure lower-amplitude stationary targets
  • a reduction of dynamic range can allow for increased magnification of data for better separation between noise and targets without generating significant artifacts that would otherwise be generated by the increased magnification
  • the process 900B may be implemented as a part of the process 900A of Fig 9 A and/or the process 400A of Fig 4A
  • the process 900B can be used as part of the calibrator (935 A) in Fig 9A
  • the process 900B may be performed using the device 150 of Fig IB or other devices
  • the device begins stepped-frequency signal transmission and monitors for transmit-to-receive leakage signal (91 OB)
  • the monito ⁇ ng may begin concurrently with the transmission or just before or after the transmission In one implementation, the monito ⁇ ng begins poor to transmission Thereafter, the change in received Attorney Docket No 10897 0064WO1 signals is used to determine the presence of transmit-to-receive leakage signal according to the techniques desc ⁇ bed below
  • a transmit-to-receive leakage signal is identified (920B)
  • the identification can be based upon various characteristics in signal received by one or more receive antennas that are indicative of transmit-to-receive leakage For example, due to the proximity of the receive antennas to the transmit antennas, transmit-to-receive leakage signal can be the strongest received signal within a short delay from transmission Specifically, transmit-to-receive leakage can occur at effectively zero distance from the device Therefore, signal reflected from locations within a short distance (e g , less than one foot) can be identified as transmit-to- receive leakage (920B)
  • Amplitude can also be used to identify transmit-to-receive leakage signal
  • transmit-to-receive leakage signal can dominate the dynamic range with an atypically high amplitude (e g , several orders of magnitude greater than the highest amplitude reflected signal) This effect is a result of the differing paths of signals
  • transmit-to-receive leakage signal often is from a direct path and signals reflected from moving objects often move through an attenuating medium (e g , a wall) there can be a significant difference in amplitude between transmit-to- receive leakage signal and signal reflected from moving objects
  • an attenuating medium e g , a wall
  • transmit-to-receive leakage signal exhibits no Doppler shift
  • transmit-to-receive leakage signal exhibits no Doppler shift
  • transmit-to-receive leakage signal is reflected from the device and received at the device Therefore, the transmission location and receive location have no difference in net movement so long as they are mechanically connected
  • a cancellation waveform configured to remove the effects of the identified transmit-to-receive leakage signal is generated (930B)
  • the cancellation waveform is configured to offset the effect, thereby effectively removing the identified transmit-to- receive leakage signal
  • a signal profile which is the inverse of the profile of the identified transmit-to-receive leakage signal can be created This cancellation waveform can effectively zero out the transmit-to-receive leakage signal Attorney Docket No 10897 0064WO1
  • the device determines whether there is additional transmit-to- receive leakage signal (940B) If there is additional transmit-to-receive leakage, the 5 process 900B identifies and generates a cancellation waveform to remove effects of the additional transmit-to-receive leakage signal (920B and 930B)
  • the iteration can be used to fine-tune the removal of a particular signal leakage path or to remove signal from multiple leakage paths For example, signal from a separate leakage path may travel further before reaching the receive antenna and may not have the same 10 amplitude or delay Multiple cancellation waveforms can be generated, or a single cancellation waveform can be adjusted with each iteration
  • the one or more cancellation waveforms are applied to remove the effects of transrmt-to-receive leakage signal of subsequent transmissions (95OB)
  • the cancellation waveform can reflect the signal profile of the identified transmit-to-
  • the one or more cancellation waveforms are applied to all subsequent transmission while the device is powered on
  • the process 900B is repeated at fixed intervals of time or
  • Fig 9C is a flow chart of an example of a process 900C to compensate for motion occurring du ⁇ ng operation of a scanning device
  • This processing approach can be used to enable the operation of the device while it is being moved intentionally or unintentionally
  • input from a motion sensor is used to facilitate the 30 adjustment of data to offset the effect of device movement
  • the process 900C may be implemented as a part of the process 900A of Fig 9A and/or the process 400A of Fig Attorney Docket No 10S97-0064WO1
  • the process 900C can be used as part of the calibrator (935A) in Fig 9A Also, the process 900C may be performed using the device 150 of Fig IB or other devices
  • the device begins stepped-frequency signal transmission (910C) and reflected portions of the signal and accompanying motion data are detected (920C)
  • Device movement can cont ⁇ bute to or otherwise alter the phase change of the reflected portions created by the movement of the reflecting object Specifically, if the device is moving towards a stationary object (e g , due to unintentional device movement), the reflected portion of the signal can exhibit a Doppler shift similar to what would be exhibited if, instead, the object had been moving towards the stationary device
  • the movement information enables adjustment for phase changes resulting from this device movement
  • the device receives movement information from an internal mertial sensor
  • the device uses a GPS sensor to de ⁇ ve device movement alone or in conjunction with an internal mertial sensor
  • processing includes generating a packet of data for received reflections of each frequency step of a sequence of frequency steps m the transmitted stepped-frequency signal and associating motion information with each packet
  • processing includes generating a packet of data for received reflections of each frequency step of a sequence of frequency steps m the transmitted stepped-frequency signal and associating motion information with each packet
  • the output of the sensor can be sampled once for each packet to determine acceleration of each of three axes
  • This acceleration information can be accumulative and can be integrated across multiple packets for determination of velocity and direction of movement
  • the generated data can be adjusted to reverse the Doppler effect resulting from the motion of the device with respect to the detected reflections
  • the position as determined by the sensor can be sampled once for each packet This position information can be used to determine velocity and direction of movement by comparing previous position information Attorney Docket No 10897 0064WO1
  • the processed data is analyzed (940C)
  • the motion determined by the motion sensor can be used during analysis to compensate or offset the perceived Doppler shift (and thus the perceived motion) of an object detected by the device
  • results of analyzed data are displayed (950C) using, for example, the techniques desc ⁇ bed above with respect to element 450A of Fig 4A
  • Fig 9D is a flow chart of an example of a process 900D to compensate for motion occurring du ⁇ ng operation of a scanning device using adaptive processing
  • This processing approach can be used to enable the operation of the device while it is being moved intentionally or unintentionally without the use of a motion sensor
  • the device analyzes data for the appearance of movement of stationary objects and uses the apparent movement to de ⁇ ve and compensate for the actual movement of the device
  • the process 900D may be implemented as a part of the process 900A of Fig 9 A and/or the process 400A of Fig 4 A
  • the process 900D can be used as part of the calibrator (935A) in Fig 9 A
  • the process 900D may be performed using the device 150 ofFig IB or other devices
  • the process 900D can be
  • the device transmits a stepped-frequency signal and detects reflected portions of the signal (910D)
  • the reflected portions are processed to generate data associated with frequency and phase shifts (920D)
  • the phase of reflected portions of the signal may exhibit a Doppler shift based on the relative movement of the object towards or away from the device If the device is moving towards a stationary object, the reflected portion of the signal can exhibit a Doppler shift similar to what would be exhibited if, instead, the object had been moving towards the stationary device Attorney Docket No 10897-0064 WO 1
  • the device identifies a phase change of reflections from stationary objects or scattering (930D)
  • the identification of the phase change can be based upon perceiving newly occurring movement (or a phase change indicative thereof) from a reflection from a previously stationary object
  • the device can identify non-movmg objects or objects of repeated mechanical movement and store the identification in memory Thereafter, the device can compare the stored identification of the pnor identified stationary object with the object's apparent movement du ⁇ ng a subsequent transmission From this comparison, the device can identify a phase change of reflections from stationary objects or scattering (930D)
  • the device can identify the phase change by analyzing a commonality in the data of reflected portions of the signal last transmitted Specifically, the device can look for consistent movement or a pattern of movement of scattering or objects which reflect the transmission For example, if the majonty of reflected portions of the signal indicate movement (l e , exhibit a phase change), the device can determine that the phase change of the reflected portions of the signal is a phase
  • the device de ⁇ ves device motion from the identified phase change (940D) Specifically, the device determines what motion of the device would produce the identified phase change of the stationary objects For example, m some implementations which generate a packet of data for received reflections of each frequency step, an adjustment is associated with each packet indicating the de ⁇ ved motion
  • the de ⁇ ved motion can be both a velocity and direction
  • the device may process the perceived motion towards and away from multiple objects of different physical locations This may include interferometnc processing techniques to determine movement of the device in three spatial dimensions Attorney Docket No 10897-0064WO1
  • the processed data is adjusted according to the de ⁇ ved device motion (950D)
  • the adjustment can include alte ⁇ ng frequency data to counteract the effect of the motion denved to have occurred for the device
  • the adjusted data is analyzed (960D) and results of the analyzed adjusted data are displayed (970D) using, for example, the techniques desc ⁇ bed above with respect to element 450A of Fig 4A
  • the adjustment may be conducted later in processing only for specific objects of significance or may be conducted earlier m processing on the data used to determine the existence of moving objects
  • Figs 1 OA- 12B and the discussion below are directed to a set of specific implementations of a scanning device referred to as a wall penetrating personnel detection sensors (WPPDS) and are provided as one possible set of implementations of a sensor for detecting moving entities as desc ⁇ bed above
  • WPPDS wall penetrating personnel detection sensors
  • a WPPDS employs a through-wall-detection radar device to detect personnel
  • the device includes a light-weight (e g , a few pounds or less), portable, dedicated through wall device for detection through walls
  • a light-weight e g , a few pounds or less
  • portable, dedicated through wall device for detection through walls
  • Particular implementations of the WPPDS are configured to detect both moving and stationary (breathing) personnel and can be useful in a va ⁇ ety of situations
  • an individual bu ⁇ ed under structural debris can be located with relative spatial position or distance and angle, which may be cntical to a life saving operation
  • the WPPDS may be used to determine the position of individuals from certain locations, which may dictate the rescue operation methodology
  • a particular implementation employs an AN/PSS-14 mine detection radar device in a miniaturized WPPDS unit that fits into a semi-automatic weapon (SAW) ammo pouch, and may operate for 180 twenty-second cycles and otherwise remain on standby du ⁇ ng a 16 hour pe ⁇ od running on eight disposable AA batten es
  • SAW semi-automatic weapon
  • Other implementations use different batteries
  • one implementations uses six CR123 type camera batteries rather than eight AA batteries
  • the WPPDS detects moving targets particularly well through non-metallic mate ⁇ als (e g , cement blocks, reinforced concrete, adobe, wallboard and plywood) Attorney Docket No 10897 0064 WOl
  • the WPPDS may employ coherent, stepped-frequency continuous wave (SFCW) radar that provides excellent through wall detection performance Detection is realized through range-Doppler processing and filtering to isolate human motion
  • SFCW stepped-frequency continuous wave
  • data from a SFCW radar may be processed as an ensemble of fixed-frequency CW radars, allowing for the optimum detection of the Doppler shift of a moving target over time via spectral analysis
  • the stepped- frequency radar data may also be processed to compress the bandwidth and obtain a high range resolution profile of the target
  • the data may be processed to remove stationary or fixed time delay data, leaving the moving target data to be evaluated in both the range and Doppler (velocity) dimensions
  • a coherent frequency-stepped radar may have an advantageous signal gam when computing the range and Doppler values of moving targets Pulse type or frequency chirp type radars may not be able to achieve the same integrated signal gam as stepped- frequency radar, due to a non-coherent nature
  • Another property of a SFCW radar is the ability to operate in environments that exhibit high radio frequency interference (RFI) Short pulse and frequency chirp radar devices maintain a wider instantaneous receive bandwidth, enabling more RFI into a processing electronics chain and reducing the signal to noise/interference level,
  • the antenna elements can be miniaturized (scaled) versions of the AN/PSS-14 cavity-backed spiral design
  • the miniaturized tactical antenna supports the selected frequency range (the upper end of the AN/PSS-14 operating range, which improves performance against rebar) and packaging constraints Attorney Docket No 10897 0064WO1
  • the RF Electronics can generate the frequency-stepped radar waveform, amplify the signal for transmission, receive energy reflected off targets using a low- noise front end, and generate coherent (in-phase and quadrature, or I & Q) signals used in the detection process
  • the transceiver electronics feature a reduced bandwidth, which enables a single voltage controlled oscillator (VCO) implementation compared to a more complex two VCO design Further device miniaturization can be achieved through implementation of a direct down-conversion (homodyne) receiver
  • a brassboard homodyne receiver has shown that significantly increased detection range in through wall applications is achievable compared to the phase- noise limited AN/PSS-14 super-heterodyne architecture
  • the reduced bandwidth of the single-board TX/RX can provide sufficient range resolution capability to support detection and can avoid the National Telecommunications and Information Administration (NTIA)/Federal Communication Commission (FCC) restrictions associated with ultra wideband (UWB) radars
  • NTIA National Telecommunications and Information Administration
  • FCC Frederal Communication Commission
  • UWB ultra wideband
  • the transmit power, coupled with the gain of the antenna, can result in a low radiated power (approximately the same as cell phones), making the device safe for human exposure
  • Some implementations use a super-heterodyne receiver with common transmit and receive local oscillators and VCOs
  • the super-heterodyne implementations can reduce phase noise as compared to the homodyne implementations
  • the digital signal processor hosts the motion detection algorithms
  • the WPPDS signal processing algorithm incorporates coherent integration gam and robust detection algorithms, achieving superior performance with greater detection range, higher probability of detection (Pd), and lower probability of false alarm (Pfa)
  • Particular implementations may be used to scan through damp concrete blocks and rebar, so as to permit ready detection of moving personnel
  • the device also can include power supply circuitry needed to convert 6V battery power for the electronics Bottoms-up power consumption calculations show that a set of disposable AA alkaline batten es may provide 180 twenty-second operating cycles
  • the low power, compact, high-performance direct-conversion radar transceiver can be realized through use of RF Monolithic Microwave Integrated Attorney Docket No 10897-0064WO1
  • MMICs and the RF integrated circuits available
  • An ultra-low phase noise Temperature Compensated Crystal Oscillator (TCXO) housed m a miniature surface- mountable package can be used as a reference to a synthesizer chip with a VCO integrated on the chip Loop response time and phase noise can be achieved and optimized via an external loop filter, creating a stable, fast-locking signal source with low divider noise
  • the signal source is then amplified by high-efficiency monolithic amplifiers with integrated active biasing circuitry and on-wafer DC blocking capacitors This approach minimizes part count and current consumption
  • This low-noise VCO is also used in the demodulation of the received radar return, which provides considerable phase noise cancellation due the oscillator coherency
  • the receiver sensitivity can be predominantly limited by thermal noise, enabling increased detection range compared to the AN/PSS-14 radar receiver This also enables an increase in transmit power for increased range
  • the direct-conversion quadrature demodulator can include polyphase filters and ensure quadrature accuracy across the entire bandwidth Pre-amplification of the LO and integrated va ⁇ able gain control of the demodulated signal can allow for efficient use of circuit board real estate and provide the device with signal conditioning flexibility to maximize signal dynamic range at the analog-to-digital (ADC) inputs
  • the digital signal processor is used to process IQ data from the radar transceiver to determine if objects are in motion and, if so, to alert the user
  • the DSP can have many features for power management, including dynamic frequency control, dynamic core voltage control, and the capability of turning off unused sections of the IC These power management features make this DSP an excellent choice for battery operated WPPDSs Operating the WPPDS at half the frequency and a core voltage of IV allows lowenng of the power and can enable a programmable performance upgrade for the future
  • a clock frequency is provided by the RF transceiver board via a Low-voltage differential signaling (LVDS) differential clock d ⁇ ver This helps Attorney Docket No 10897 0064WO1 protect signal integrity and reduces electromagnetic interference (EMI) caused by the fast clock edge rates
  • the design features 8M bytes of synchronous dynamic random access memory (SDRAM) for fast program access and enough storage for 60 seconds of captured data per operating cycle
  • 4M bytes of flash memory are used for booting up the DSP and for non- volatile storage
  • SDRAM synchronous dynamic random access memory
  • USB universal se ⁇ al bus
  • An ADC includes an 18 bit ADC that allows a 15 dB increase in signal-to-noise ratio (SNR) to take advantage of the increased dynamic range and sensitivity Differential inputs improve common-mode noise cancellation, allowing for a more sensitive detector
  • the op-amps are selected for low power, low noise performance as amplifiers and active filters
  • a 16 bit DAC is used to cancel the DC offset from the incoming IQ signals from the RF Electronics Serial communication protocol (SPI) is used to communicate with the ADC, digital-to- analog converter (DAC), and RF phase-locked loop(PLL), which helps reduce I/O requirements and
  • Fig 1OA is a picture of a handheld stepped- frequency scanning device relative to a SAW ammo pouch
  • the housing layout is able to be configured with three circuit card assemblies (CCA), which enables an optional integrated battery recharging circuit, such as a generally commercially available integrated battery recharging circuit
  • CCA circuit card assemblies
  • the miniature cavity- backed spiral antennas each contain a planar feed assembly that connects directly to the RF CCA
  • the Digital CCA contains the DSP as well as the power supply (PS) circuitry
  • Fig 1OB is a picture of a handheld stepped- frequency scanning device m a case
  • the WPPDS unit and accesso ⁇ es can fit into a standard Pelican TM case for storage and transportation
  • the packaging provides protection against transportation shock and vibration, environmental protection, and facilitates safe storage and ease of handling while in daily use by soldiers or rescuers
  • the case includes compartments Attorney Docket No 10897 0064WO1 for sto ⁇ ng arm straps, extra batteries, and an optional vehicle-compatible battery recharger
  • the operator may hold the device by the straps or by the sides of the unit, affix the unit to either arm via the straps (forearm or upper arm), or mount the device to a pole or t ⁇ pod (pole/t ⁇ pod not provided with unit)
  • a standard video camera mount may be connected to the bottom of the unit to facilitate mounting to a tnpod or pole
  • the housing design also features raised stiffener ⁇ dges on the front that may facilitate temporary wall mounting using putty
  • Other implementations may not include the straps, enabling users to operate the device without connecting it to their person
  • the housing is made of impact-resistant ABS plastic to help provide protection if the case is dropped or collides with hard objects that may occur dunng training exercises or dunng operation, such as on a battlefield or m a rescue operation
  • the external design of the housing incorporates human factor features to simplify operation in difficult environments
  • a rubber shield protects the front of the unit Rubber grip pads are also provided in four areas to facilitate slip-free handheld operation
  • Multiple SCAN switches support a va ⁇ ety of operational situations
  • Fig 1 IA is a picture illustrating battery access in a handheld stepped- frequency scanning device
  • the battery holder assembly features all eight battenes in the same o ⁇ entation for easy installation under low light / time critical conditions
  • the total power draw from battenes can be 2 2W
  • four battenes are connected in senes, and 2 sets of 4 battenes in parallel This provides 6 V and divides the power by the 2 battery sets
  • Fig 11 B is a graph illustrating power discharge charactenstics in a handheld stepped-frequency scanning device Dunng run time the individual battery voltage is allowed to decay from 1 4V to 09V, providing approximately 1 hour of operation time
  • Fig 12A is a picture illustrating recessed light emitting diodes in a handheld stepped-frequency scanning device
  • the device can include light emitting diodes (LEDs) recessed to provide shadowing to enhance daytime vision with or without a display screen (not shown)
  • Fig 12B is a picture illustrating operational controls of a handheld stepped-frequency scanning device Power of the device can be affected Attorney Docket No 10897-0064WO1 through use of the OFF and STDBY controls In Standby mode the circuitry is placed m a power-save mode, and activation of any one of three SCAN pressure switches (one front, two bottom) initiates immediate sensor operation The device returns to standby mode when the SCAN button is released
  • Other implementations may include other interface arrangements For example, a combination of two SCAN switches could be simultaneously pressed (but not held) to enable timed operation, such as when the unit is temporarily adhered to or leaned against a wall, or mounted to a tnpod, for hands-off operation
  • four color LEDs are used to provide indications to the operator without a display screen
  • the yellow STANDBY LED indicates power status steady illumination indicates power is on
  • flashing LED indicates low battery power
  • the red FAULT LED indicates one of several conditions steady illumination indicates that the device is unable to make an accurate measurement due to metal blockage, electromagnetic interference (e g , jamming), or excessive motion of the sensor
  • flashing illumination indicates a built-m-test (BIT) failure
  • BIT built-m-test
  • the green SCANNING LED remains illuminated while the unit is operating to detect motion
  • the blue DETECT LED indicates that motion has been detected
  • Steady illumination indicates personnel motion detection at a closer distance
  • a flashing DETECT LED indicates personnel motion detection at a farther distance
  • a change m color for the blue DETECT (to Magenta) indicates that subtle movement has been detected
  • the device may be powered on and placed in standby mode by momenta ⁇ ly pressing the STDBY switch
  • the device may be powered off by simultaneously pressing the STDBY and OFF switches This may prevent accidental power-down du ⁇ ng normal operation should the OFF switch get accidentally bumped
  • circuitry is activated in power-save mode, and the device may be immediately operated by pressing one of the SCAN switches
  • the front SCAN switch may be activated by pressing and holding the device against the wall to be penetrated
  • One of two bottom SCAN switches may be activated by squeezing with the thumb (normal device o ⁇ entation) or index finger (inverted orientation), or by pressing the device against the knee or thigh when in a kneeling position Attorney Docket No 10897-0064WO 1
  • the green SCAN LED When any SCAN switch is depressed, the green SCAN LED may illuminate, and may remain illuminated as long as the SCAN switch is depressed This may alert the operator that the device is operational (i e , that the SCAN switch is properly depressed)
  • a blue DETECT LED may be used to alert the operator of detected personnel
  • the device may also be programmed to detect subtle movement This mode may be initiated by pressing any SCAN switch twice in rapid succession
  • the green SCAN LED may pulsate slowly when this mode is active
  • the blue DETECT LED may illuminate when slow movement (respiration) is detected
  • Some implementations use alternative manners of communicating information to users For example, one implementations uses a light emitting diode screen to render a two digit number to express a distance of detected moving objects Other implementations use more sophisticated screens (e g , more advanced light emitting diodes, organic light emitting diodes, etc ) to render three dimensional representations and more complex information

Landscapes

  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

L'invention concerne un système et un procédé pour permettre la transmission d'un signal radar à fréquences échelonnées, ce système et ce procédé pouvant faire intervenir une première antenne et une seconde antenne. Le système selon l'invention peut comprendre également des circuits de réception conçus pour recevoir des réflexions détectées en provenance des antennes et pour générer des données contenant des informations associées à des décalages de fréquence et de phase. Ce système peut comprendre en outre un processeur conçu pour recevoir les données générées en provenance des circuits de réception et pour analyser ces données pour déterminer des informations associées à un objet en mouvement situé d'un côté d'une paroi à l'opposé du système par différenciation entre les réflexions du signal transmis détectées au moyen de la première antenne et les réflexions du signal transmis détectées au moyen de la seconde antenne.
EP09747027A 2008-02-25 2009-02-24 Détection d'une entité en mouvement Ceased EP2255218A4 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US3111308P 2008-02-25 2008-02-25
PCT/US2009/035009 WO2009139941A1 (fr) 2008-02-25 2009-02-24 Détection d'une entité en mouvement

Publications (2)

Publication Number Publication Date
EP2255218A1 true EP2255218A1 (fr) 2010-12-01
EP2255218A4 EP2255218A4 (fr) 2012-03-07

Family

ID=41318992

Family Applications (2)

Application Number Title Priority Date Filing Date
EP09747027A Ceased EP2255218A4 (fr) 2008-02-25 2009-02-24 Détection d'une entité en mouvement
EP09747026.4A Not-in-force EP2257831B1 (fr) 2008-02-25 2009-02-24 Détection d'une entité en mouvement

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP09747026.4A Not-in-force EP2257831B1 (fr) 2008-02-25 2009-02-24 Détection d'une entité en mouvement

Country Status (4)

Country Link
EP (2) EP2255218A4 (fr)
AU (2) AU2009246792A1 (fr)
CA (2) CA2715902A1 (fr)
WO (2) WO2009139940A1 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9063232B2 (en) 2005-04-14 2015-06-23 L-3 Communications Security And Detection Systems, Inc Moving-entity detection
US8362942B2 (en) 2005-04-14 2013-01-29 L-3 Communications Cyterra Corporation Moving-entity detection
US8779965B2 (en) 2009-12-18 2014-07-15 L-3 Communications Cyterra Corporation Moving-entity detection
US9229102B1 (en) 2009-12-18 2016-01-05 L-3 Communications Security And Detection Systems, Inc. Detection of movable objects
CA2691924A1 (fr) * 2010-02-05 2011-08-05 Sensotech Inc. Systeme de protection virtuelle de l'operateur
DE102016207463A1 (de) * 2016-04-29 2017-11-02 Robert Bosch Gmbh Verfahren und Vorrichtung zum Betreiben wenigstens eines Fahrzeugs in Bezug auf wenigstens ein passierbares Objekt in der Umgebung des wenigstens einen Fahrzeugs
CN109828249A (zh) * 2019-02-22 2019-05-31 北京遥感设备研究所 一种用于综合孔径辐射计阵列的定标方法
US20240111046A1 (en) * 2019-11-12 2024-04-04 GE Precision Healthcare LLC Method and system for flow processing on channel data for application of nonlinear beamforming
CN113219425B (zh) * 2021-05-11 2022-11-22 上海涵润汽车电子有限公司 一种雷达目标检测性能的测试方法及系统

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070171119A1 (en) * 2006-01-24 2007-07-26 Raytheon Company Micro movement pulsed radar system and method of phase noise compensation
WO2008001092A2 (fr) * 2006-06-28 2008-01-03 Cambridge Consultants Limited Radar

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3347571B2 (ja) * 1996-03-12 2002-11-20 富士通株式会社 レーダ装置
US5673050A (en) * 1996-06-14 1997-09-30 Moussally; George Three-dimensional underground imaging radar system
US5923280A (en) * 1997-01-17 1999-07-13 Automotive Systems Laboratory, Inc. Vehicle collision radar with randomized FSK wave form
US5861837A (en) * 1997-03-19 1999-01-19 Northrop Grumman Corporation Poly-frequency CW doppler radar system with leakage cancellation and method
US6417797B1 (en) * 1998-07-14 2002-07-09 Cirrus Logic, Inc. System for A multi-purpose portable imaging device and methods for using same
US6518915B2 (en) * 2000-11-15 2003-02-11 Geophysical Survey Systems, Inc. Impulse radar security system
US6501414B2 (en) * 2001-04-02 2002-12-31 The United States Of America As Represented By The United States National Aeronautics And Space Administration Method for locating a concealed object
US6512976B1 (en) * 2001-04-27 2003-01-28 Honeywell International Inc. Method and system for terrain aided navigation
US7310060B2 (en) * 2003-08-15 2007-12-18 L-3 Communications Cyterra Corporation Multi-mode landmine detector
US6909397B1 (en) * 2003-12-10 2005-06-21 Georgia Tech Research Corporation Stabilizing motion in a radar detection system using ultrasonic radar range information
US7089099B2 (en) * 2004-07-30 2006-08-08 Automotive Technologies International, Inc. Sensor assemblies
US7768445B2 (en) * 2004-08-02 2010-08-03 Mitsubishi Electric Corporation Frequency-modulated radar system with variable pulse interval capability
US7679545B2 (en) * 2004-08-05 2010-03-16 Georgia Tech Research Corporation Suppressing motion interference in a radar detection system
US7307575B2 (en) * 2004-09-14 2007-12-11 Bae Systems Information And Electronic Systems Integration Inc. Through-the-wall frequency stepped imaging system utilizing near field multiple antenna positions, clutter rejection and corrections for frequency dependent wall effects
US6970128B1 (en) * 2004-10-06 2005-11-29 Raytheon Company Motion compensated synthetic aperture imaging system and methods for imaging

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070171119A1 (en) * 2006-01-24 2007-07-26 Raytheon Company Micro movement pulsed radar system and method of phase noise compensation
WO2008001092A2 (fr) * 2006-06-28 2008-01-03 Cambridge Consultants Limited Radar

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2009139941A1 *

Also Published As

Publication number Publication date
EP2255218A4 (fr) 2012-03-07
CA2716001A1 (fr) 2009-11-19
WO2009139940A1 (fr) 2009-11-19
CA2715902A1 (fr) 2009-11-19
EP2257831B1 (fr) 2016-11-16
WO2009139941A1 (fr) 2009-11-19
AU2009246791A1 (en) 2009-11-19
EP2257831A4 (fr) 2012-05-23
AU2009246792A1 (en) 2009-11-19
EP2257831A1 (fr) 2010-12-08

Similar Documents

Publication Publication Date Title
US9063232B2 (en) Moving-entity detection
US8362942B2 (en) Moving-entity detection
EP2513666B1 (fr) Détection d'une entité en mouvement
EP2257831B1 (fr) Détection d'une entité en mouvement
US9229102B1 (en) Detection of movable objects
US20150301167A1 (en) Detection of movable objects
US7345618B1 (en) Moving-entity detection
WO2011146517A2 (fr) Système, procédés et dispositifs de surveillance et de suivi de patients
Leib et al. Vital signs monitoring with a UWB radar based on a correlation receiver
WO2012158840A1 (fr) Suivi des patients et étiquette de surveillance
Wang et al. Concurrent vital sign and position sensing of multiple individuals using self-injection-locked tags and injection-locked I/Q receivers with arctangent demodulation
CN113608174A (zh) 多传感器射频检测
WO2021035197A1 (fr) Communication sans fil à conformité d'exposition maximale autorisée (mpe) améliorée en fonction de la détection de signes vitaux
US20140300502A9 (en) Millimeter Wave Energy Sensing Wand and Method
Li et al. Recent advances in Doppler radar sensors for pervasive healthcare monitoring
Jardak et al. Compact mmWave FMCW radar: Implementation and performance analysis
Santra et al. Short-range multi-mode continuous-wave radar for vital sign measurement and imaging
Fioranelli et al. Frequency-modulated interrupted continuous wave as wall removal technique in through-the-wall imaging
Lin et al. A broadband MFCW agile radar concept for vital-sign detection under various thoracic movements
Li et al. Portable Doppler/FSK/FMCW radar systems for life activity sensing and human localization
Hung et al. Non-invasive detection of object by UWB radar
Borek et al. Through-the-wall surveillance for homeland security and law enforcement
US20240065633A1 (en) Radar-aided warning system for pacemaker wearers against potential electromagnetic interference by mobile device
Singh et al. Advanced Performance Architectures
Tang A Frequency-Modulated Continuous Wave-Based Boundary Detection System for Determination of Monitoring Region for an Indoor Ultra-Wideband Short Range Radar-Based Eldercare Monitoring System

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20100920

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA RS

DAX Request for extension of the european patent (deleted)
A4 Supplementary search report drawn up and despatched

Effective date: 20120206

RIC1 Information provided on ipc code assigned before grant

Ipc: G01S 13/00 20060101AFI20120131BHEP

17Q First examination report despatched

Effective date: 20120417

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

REG Reference to a national code

Ref country code: DE

Ref legal event code: R003

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED

18R Application refused

Effective date: 20191107