SE541952C2 - Radar apparatus and method with interference detection - Google Patents

Radar apparatus and method with interference detection

Info

Publication number
SE541952C2
SE541952C2 SE1530160A SE1530160A SE541952C2 SE 541952 C2 SE541952 C2 SE 541952C2 SE 1530160 A SE1530160 A SE 1530160A SE 1530160 A SE1530160 A SE 1530160A SE 541952 C2 SE541952 C2 SE 541952C2
Authority
SE
Sweden
Prior art keywords
radar apparatus
region
interest
roi
radiation
Prior art date
Application number
SE1530160A
Other versions
SE1530160A1 (en
Inventor
Thomas Pernstål
Original Assignee
Qamcom Tech Ab
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 Qamcom Tech Ab filed Critical Qamcom Tech Ab
Priority to SE1530160A priority Critical patent/SE541952C2/en
Priority to PCT/SE2016/050993 priority patent/WO2017069679A1/en
Publication of SE1530160A1 publication Critical patent/SE1530160A1/en
Publication of SE541952C2 publication Critical patent/SE541952C2/en

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/36Means for anti-jamming, e.g. ECCM, i.e. electronic counter-counter measures
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/88Radar or analogous systems specially adapted for specific applications
    • G01S13/93Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/021Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/023Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/023Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques
    • G01S7/0232Avoidance by frequency multiplex
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S7/00Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/023Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques
    • G01S7/0234Avoidance by code multiplex
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B61RAILWAYS
    • B61LGUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L23/00Control, warning or like safety means along the route or between vehicles or trains
    • B61L23/04Control, warning or like safety means along the route or between vehicles or trains for monitoring the mechanical state of the route
    • B61L23/041Obstacle detection
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B61RAILWAYS
    • B61LGUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
    • B61L29/00Safety means for rail/road crossing traffic
    • B61L29/24Means for warning road traffic that a gate is closed or closing, or that rail traffic is approaching, e.g. for visible or audible warning
    • B61L29/28Means for warning road traffic that a gate is closed or closing, or that rail traffic is approaching, e.g. for visible or audible warning electrically operated
    • B61L29/30Supervision, e.g. monitoring arrangements
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/02Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06Systems determining position data of a target
    • G01S13/08Systems for measuring distance only
    • G01S13/10Systems for measuring distance only using transmission of interrupted, pulse modulated waves
    • G01S13/22Systems for measuring distance only using transmission of interrupted, pulse modulated waves using irregular pulse repetition frequency
    • G01S13/222Systems for measuring distance only using transmission of interrupted, pulse modulated waves using irregular pulse repetition frequency using random or pseudorandom pulse repetition frequency
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/02Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06Systems determining position data of a target
    • G01S13/08Systems for measuring distance only
    • G01S13/10Systems for measuring distance only using transmission of interrupted, pulse modulated waves
    • G01S13/26Systems for measuring distance only using transmission of interrupted, pulse modulated waves wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/02Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06Systems determining position data of a target
    • G01S13/08Systems for measuring distance only
    • G01S13/32Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/34Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • G01S13/343Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal using sawtooth modulation
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/02Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06Systems determining position data of a target
    • G01S13/08Systems for measuring distance only
    • G01S13/32Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/34Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • G01S13/346Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal using noise modulation
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/02Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06Systems determining position data of a target
    • G01S13/08Systems for measuring distance only
    • G01S13/32Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/34Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • G01S13/347Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal using more than one modulation frequency
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/88Radar or analogous systems specially adapted for specific applications
    • G01S13/883Radar or analogous systems specially adapted for specific applications for missile homing, autodirectors
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/88Radar or analogous systems specially adapted for specific applications
    • G01S13/91Radar or analogous systems specially adapted for specific applications for traffic control
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems 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
    • G01S13/02Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06Systems determining position data of a target
    • G01S13/46Indirect determination of position data
    • G01S2013/468Indirect determination of position data by Triangulation, i.e. two antennas or two sensors determine separately the bearing, direction or angle to a target, whereby with the knowledge of the baseline length, the position data of the target is determined

Landscapes

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

Abstract

A radar apparatus (10) includes an antenna arrangement for emitting interrogating radiation (50) to a region of interest (ROI, 20) and for receiving corresponding reflected radiation (60) from the region of interest (ROI, 20), and a signal processing arrangement (DSP) for generating signals for providing the interrogating radiation (50) and for processing received signals corresponding to the reflected radiation (60). Moreover, the radar apparatus (10) is operable to emit repetitively in the interrogating radiation (50) a sequence of test tones for interrogating the region of interest (ROI, 20) and the signal processing arrangement (DSP) is operable to process the reflected radiation (60) to determine from test tone information included in the reflected radiation (60) one or more objects in the region of interest (ROI, 20). In a listening period (80) between repetitive emission of the sequence of test tones, the radar apparatus (10) is operable to detect one or more interfering signals being emitted from the region of interest (ROI, 20), for distinguishing signal components arising from the one or more objects from the one or more interfering signals.

Description

RADAR APPARATUS AND METHOD WITH INTERFERENCE DETECTION Technical Field The present disclosure relates to radar apparatus, for example radar apparatus which is operable to emit and receive electromagnetic radiation at a frequency of substantially 77 GHz for interrogating a spatial region. Moreover, the present disclosure concerns methods of operating aforesaid radar apparatus, for example to enable aforesaid apparatus to distinguish more effectively between desired and interfering signals. Furthermore, the present disclosure is concerned with computer program products comprising a non-transitory computer-readable storage medium having computerreadable instructions stored thereon, the computer-readable instructions being executable by a computerized device comprising processing hardware to execute aforesaid methods.
Background In overview, radar apparatus is well known and includes an emitting arrangement for emitting electromagnetic radiation towards a region of interest and a receiving arrangement for receiving a portion of the emitted electromagnetic radiation which is reflected back from the region of interest (ROI). On account of the emitting arrangement and/or the receiving arrangement having polar characteristics having directions of greater gain, the apparatus is capable of mapping out the region of interest. Moreover, time-of-flight and Doppler frequency shift information included in the portion of the emitted electromagnetic radiation which is reflected back from the region of interest enables one of more objects in the region of interest (ROI) to be monitored, for example as in Doppler radar systems for selectively measuring speeds of road vehicles.
In a United States patent application US2005/0035903A1 (inventor Bergkvist et al.; applicant: Saab AB), there is described a radar apparatus which is arranged to transmit electromagnetic energy in pulse repetition intervals and to receive reflections or echoes from objects in range gates intended for such purpose, wherein the range gates are provided with Doppler filters. The radar apparatus is arranged to approve ambiguous echoes that are desirable and to suppress ambiguous echoes that are of no interest or that interfere with a display function of the radar apparatus. The radar apparatus operates with a frequency of electromagnetic radiation, that is emitted therefrom and is received thereat, that varies according to a staggered or wobbling temporal pattern. The respective ambiguous echoes produce oniy one pulse in respective range gates concerned, within a predetermined number of periods. A respective Doppler filter concerned is arranged to work with an impulse function response that only consists of a small number of samples. The Doppler filter is also arranged, during the predetermined number of periods, to give rise to a plurality of independent samples from reflectors within the radar apparatus’ unambiguous range. When the independent samples exceed a small number of samples, the radar apparatus approves the ambiguous echo; otherwise, it is suppressed. In such a manner, ambiguous echoes are prevented from interfering with reception at the radar apparatus, or display of the echoes on a display screen of the radar apparatus. The suppression of asynchronous interferences, for example pulses from other radar stations, can also be made easier in a simple way.
In a Japanese patent application JP2002/174677A, there is described a radar apparatus which is capable of detecting continuously, for example for trapping and tracking a target in a military situation, even if interfering waves are transmitted from the target, when the target is a menace such as a enemy aircraft. The radar apparatus utilizes information regarding interfering electromagnetic radiation, for example its centre frequency and a bandwidth of its signal components, emitted from the target. In operation an operating frequency of the radar apparatus is changed to avoid a frequency regime in which the interfering electromagnetic radiation from the target occurs.
In a Canadian patent CA 2762762 A1 (“ Radar System and Method’· inventor - Oswald et al.', applicant - Cambridge Consultants Ltd.), there is described a radar system for discriminating between sources of radar interference and targets of interest. The system includes a transmitter for transmitting radar signals into a region, a receiver for receiving return signals of the radar signals returned from within the region, and a processor for processing the return signals to discriminate between return signals returned from a first object and return signals returned from a second object, where the return signals from the second object comprise both zero and non-zero Doppler components and interfere with the return signals from the first object. The radar system is operable for discriminating between the return signals when the return signals are received at a distance from the second object which is less than a proximity limit based on the geometry of the object.
From the foregoing, it will be appreciated that interference can occur in operation of a given radar system, for example various forms of deliberate or coincidental interference, for example from on-board vehicle radar systems in a congested traffic situation. When radar systems are employed to provide automated braking and/or automated steering of vehicles on highways, such interference can potentially cause hazardous situations to arise. There is therefore a need to improve radar apparatus to make it less susceptible to interference.
Summary The present disclosure seeks to provide an improved radar apparatus which is more effectively capable of distinguishing signals arising from one or more interfering sources in a region of interest (ROI) in comparison to reflections of interrogating radiation from one or more objects within the region of interest (ROI).
Moreover, the present disclosure seeks to provide an improved method of operating a radar system for more effectively distinguishing signals arising from one or more interfering sources in a region of interest (ROI) in comparison to reflections of interrogating radiation from one or more objects within the region of interest (ROI).
According to a first aspect of the present invention, there is provided radar apparatus including an antenna arrangement for emitting interrogating radiation to a region of interest (ROI) and for receiving corresponding reflected radiation from the region of interest (ROI), and a signal processing arrangement (DSP) for generating signals for providing the interrogating radiation and for processing received signals corresponding to the reflected radiation, characterized in that the radar apparatus is operable to emit repetitively in the interrogating radiation a sequence of test tones for interrogating the region of interest (ROI) and the signal processing arrangement (DSP) is operable to process the reflected radiation to determine from test tone information included in the reflected radiation one or more objects in the region of interest (ROI), and in a listening period between repetitive emission of the sequence of test tones, the radar apparatus is operable to detect one or more interfering signals being emitted from the region of interest (ROI), for distinguishing signal components arising from the one or more objects from the one or more interfering signals.
The invention is of advantage that the radar apparatus is susceptible to being operated for more effectively identifying the one or more sources of interrogating radiation by employing the sequence of test tones in combination with the listening period.
Optionally, the radar apparatus is operable to detect at least one spatial range of at least one source giving rise to the one or more interfering signals. More optionally, the radar apparatus is operable to compute the at least one spatial range by employing at least one triangulation measurement, and to apply a Kalman filter to measurement results of the at least one triangulation measurement. Yet more optionally, in the radar apparatus, the Kalman filter is operable to employ a motion estimation of motion of the at least one source.
Optionally, the radar apparatus is operable to generate the sequence of test tones to include one or more chirped tones.
Optionally, the radar apparatus is operable to generate the sequence of test tones in a pseudo-random manner.
Optionally, the radar apparatus is operable to vary at least one of: (i) a duration of the listening period: and (ii) a duration of a pulse train including the sequence of test tones.
More optionally, the radar apparatus is operable to process received signals during the listening period in a plurality of time periods, and to detect for signal components corresponding to the one or more interfering signals for each of the plurality of time periods.
Optionally, the radar apparatus is operable to emit to, and receiver radiation from, the region of interest (ROI) at an electromagnetic frequency range in a range of 30 GHz to 200 GHz, more optionally in a range of 50 GHz to 150 GHz, and yet more optionally substantially 77 GHz.
Optionally, the radar apparatus is arranged to interrogate the region of interest (ROI), wherein the region of interest (ROI) includes at least one of: (a) a railway crossing ; (b) a region around a road vehicle onto which the radar apparatus is mounted in operation; and (c) a region around a projectile onto which the radar apparatus is mounted in operation.
According to a second aspect, there is provided a method of using radar apparatus including an antenna arrangement for emitting interrogating radiation to a region of interest (ROI) and for receiving corresponding reflected radiation from the region of interest (ROI), and a signal processing arrangement (DSP) for generating signals for providing the interrogating radiation and for processing received signals corresponding to the reflected radiation, characterized in that the method includes: (i) operating the radar apparatus to emit repetitively in the interrogating radiation a sequence of test tones for interrogating the region of interest (ROI); (ii) operating the signal processing arrangement (DSP) to process the reflected radiation to determine from test tone information included in the reflected radiation one or more objects in the region of interest (ROI); and (iii) in a listening period between repetitive emission of the sequence of test tones, the radar apparatus is operable to detect one or more interfering signals being emitted from the region of interest (ROI), for distinguishing signal components arising from the one or more objects from the one or more interfering signals.
Optionally, the method includes operating the radar apparatus to detect at least one spatial range of at least one source giving rise to the one or more interfering signals, More optionally, the method includes operating the radar apparatus to compute the at least one spatial range by employing at least one triangulation measurement, and to apply a Kalman filter to measurement results of the at least one triangulation measurement. Yet more optionally, the method includes using a Kalman filter that is operable to employ a motion estimation of motion of the at least one source.
Optionally, the method includes operating the radar apparatus to generate the sequence of test tones to include one or more chirped tones.
Optionally, the method includes operating the radar apparatus to generate the sequence of test tones in a pseudo-random manner.
Optionally, the method includes operating the radar apparatus to vary at least one of: (i) a duration of the listening period; and (ii) a duration of a pulse train including the sequence of test tones.
More optionally, the method includes operating the radar apparatus to process received signals during the listening period in a plurality of time periods, and to detect for signal components corresponding to the one or more interfering signals for each of the plurality of time periods.
Optionally, the method includes operating the radar apparatus to emit to, and receiver radiation from, the region of interest (ROI) at an electromagnetic frequency range in a range of 30 GHz to 200 GHz, more optionally in a range of 50 GHz to 150 GHz, and yet more optionally substantially 77 GHz.
Optionally, the method includes arranging tor the radar apparatus to interrogate the region of interest (ROI), wherein the region of interest (ROI) includes at least one of: (a) a railway crossing; (b) a region around a road vehicle onto which the radar apparatus is mounted in operation; and (c) a region around a projectile onto which the radar apparatus is mounted in operation.
According to a third aspect, there is provided a computer program product comprising a non-transitory computer-readable storage medium having computer-readable instructions stored thereon, the computer-readable instructions being executable by a computerized device comprising processing hardware to execute a method pursuant to the second aspect.
It will be appreciated that features of the invention are susceptible to being combined in various combinations without departing from the scope of the invention as defined by the appended claims.
Description of the diagrams Embodiments of the present invention will now be described, by way of example only, with reference to the following diagrams wherein: FIG. 1 is a schematic illustration of a radar apparatus pursuant to the present disclosure for interrogating a region of interest (ROI); FIG. 2 is a graph illustrating a regime of test frequencies, which are optionally chirped, with listening periods therebetween; and FIG. 3 is a graph illustrating a frequency and amplitude distribution for test and interfering signals of the radar apparatus of FIG. 1 when in operation.
In the accompanying diagrams, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
Description of embodiments of the invention In overview, referring to FIG. 1, embodiments of the present disclosure are concerned with radar apparatus, indicated by 10. The radar apparatus 10 employs a method of detecting interferences in all spatial directions of operation of the radar apparatus 10, via use of several continuous wave (CW) signals, for example by employing radar signals that have a principal frequency component in a range of 76.0 GHz to 76.5 GHz, which are relatively short in duration; between periods of transmitting and correspondingly receiving radar signals, the radar apparatus 10 employs, temporally, a listening period in which interfering signals are detected by the radar apparatus 10.
Optionally, for example, in operation, a pulse train, for example a pulse train having a period in a range of 2 to 20 ms, for example substantially a pulse train having a duration of 5 ms, for transmitting and correspondingly receiving, radar signals is employed, wherein electromagnetic radar radiation is employed to interrogate a given spatial region of interest (ROI), with a listening period therebetween that is less than 2 ms, for example less than 1 ms, for listening for interfering signals originating from the region of interest (ROI) 20. Optionally, the listening period is in a range of 2% to 30% of a total repetition period, wherein the total repetition period is a sum of the pulse train and the listening period.
By introducing a listening interval prior to using an actual waveform signal, namely a “ pulse train ", being emitted into the region of interest (ROI) 20 and corresponding reflected radiation being received, the radar apparatus 10 is operable to scan for determining a magnitude, frequency location and direction of one or more sources of disturbance and/or interference 30 present within the region of interest (ROI) 20. Thus, using such information, the radar apparatus 10 is operable either to select suitable frequencies of its own transmitted radar energy or to employ interference suppression algorithms.
The radar apparatus 10 is operable to estimate a range of a given interfering source of disturbance and/or interference 30 , giving rise to interfering signals in the listening period by employing a multiple range model, namely hypothesis, that is based upon utilizing several listening interval measurements. Such an approach enables the source 30 to be identified with a greater degree of certainty, and its distance determined from temporal computations. Beneficially, the radar apparatus 10 is operable to employ triangulation, namely measurements performed at two or more spatial locations of the radar apparatus 10 relative the source 30, for determining motion of the source 30. In order to determine an estimation of the range of the source from the radar apparatus 10, there is computed a probability, namely likelihood, of a hypothesis of the source 30 being within a given assumed range from the radar apparatus 10; such determination is, for example, usefully implemented using a Kalman filter or similar approach. Using a variable listening period, also assists the radar apparatus 10 to detect sources 30 that are operating to cause interference, but evading detection by intelligently becoming silent during the listening period of the radar apparatus 10, for example when the sources 30 are malicious with intend of confusing the radar apparatus 10.
A Kalman filter, also known as a “linear quadratic estimation", is an algorithm that uses a series of temporal measurements, containing statistical noise, for example stochastic noise, and other inaccuracies, and produces estimates of unknown variables that tend to be more precise than those based on a single measurement alone. Moreover, the Kalman filter algorithm functions in a two-step process including: (a) a first prediction step, wherein the Kalman fi!ter estimates a current state of one or more variables, together with associated uncertainties; and (b) a second step of updating the estimates derived from the first predication step using a weighted average, with more weight being given to estimates of greater certainty, wherein the first and second steps are performed recursively.
Optionally, the radar signals employed in the radar apparatus 10, to provide corresponding electromagnetic radar radiation for interrogating the region of interest (ROI) 20 and to receive corresponding reflected electromagnetic radiation therefrom, is a chirped signal, namely a frequency swept signal.
Referring to FIG. 2, there is shown a temporal graph of a signal employed by the radar apparatus 10 when in operation. The radar apparatus 10 is operable to employ the signal to generate interrogating radiation 50 to emit towards the region of interest (ROI) 20, and to receive at the radar apparatus 10 corresponding reflected radiation 60 from the region of interest (ROI) 20. The signal corresponds to a plurality of different frequency steps 70A, 70B, 70C, 70D and so forth, for example wherein a chirp frequency sweep is employed within each step, following by a listening period 80, during which the radar apparatus 10 is operable to listen to potentially interfering signals generated within the region of interest (ROI) 20. The frequency steps 70A, 70B, 70C, 70D and so forth optionally employ a sequence of operating frequencies that are repeated after each listening period; such a repeated form of signal is beneficially correlated with the reflected radiation from the region of interest (ROI) during detection, to achieve an improved reliability of detection of one or more objects in the region of interest (ROI) 20. Alternatively, the frequency steps 70A, 70B, 70C, 70D and so forth are optionally varied in a pseudo-random manner to prevent hostile interfering sources in the region of interest (ROI) 20 from recognizing the sequence of steps 70A, 70B, 70C, 70D and so forth and deliberately attempting to disrupt operation of the radar apparatus 10; again, aforementioned correlation of the reflected radiation 60, as a corresponding received signal in the radar apparatus 10, with pseudo-random changes employed in generating the interrogating radiation 50, to provide more reliable detection of one or more objects in the region of interest (ROI) 20. Thus, embodiments of the present disclosure employ a special form of radar signal in a radar apparatus 10, including a period to listen for interfering radar radiation from other sources in the region of interest (ROI) 20.
In an example situation as illustrated in FIG. 3, wherein an abscissa axis 100 denotes frequency, and an ordinate axis 110 denotes amplitude. There is a 76.5 GHz jamming signal 120 emitted from the region of interest (ROI) 20, for example from a source of noise or interfering radiation, so the radar apparatus 10 pursuant to the present disclosure is operable to select a 76.0 GHz operation with a chirp to substantially 76.5 GHz, namely is operable to employ chirped signals at various CW test frequencies denoted by 130; a 5 ms pulse train of chirp signals is emitted from the radar apparatus 10 as the interrogating radiation 50 to the region of interest (ROI) 20, after which a 1 msec (ms) listening period is employed to listen for identifying interfering radiation being generated in the region of interest (ROI) 20. Optionally, the duration of the pulse trains is varied, for example in a pre-determined or pseudo-random manner, to circumvent a situation that an interfering source present in the region of interest (ROI) becomes aware of the manner of operation of the radar apparatus 10, and synchronizes to be inactive during the listening period of the radar apparatus 10, thereby attempting to avoid detection Optionally, the radar apparatus 10 is operable to partition the listening period into a plurality of temporal portions, for example by using time-gates in the radar apparatus 10, and to analyze signals generated by interfering sources in the region of interest (ROI) for each of these temporal portions; such an approach is advantageous combined with making the pulse train period and/or the listening period temporally varying, for example in a pre-determined or pseudo-random manner; in such case, it is very difficult for an interfering source of radiation present in the region of interest 20 to evade detection for any extensive period of time.
More specifically, in frequency modulated continuous wave (FMCW) radar systems, there is typically employed chirp bandwidths of several 100 MHz, that are then, upon being emitted as the interrogating radiation 50 to the region of interest (ROI) 20 and then reflected therefrom as the reflected radiation 60, de-chirped with reference to a given signal employed to generate the interrogating radiation 50 down to baseband signals for subsequent processing in the radar apparatus 10, for example for timegating and/or correlation algorithms. In the radar apparatus 10, there are employed a plurality of continuous wave (CW) tones covering an instantaneous bandwidth of the radar waveform employed; it is then feasible to process a signal corresponding to the reflected radiation 60 to determine a spatial location, frequency range and emitting power of one or more interfering sources within the region of interest 20. The frequency steps employed between the individual continuous wave (CW) frequencies corresponds to a baseband bandwidth of a receiver section of the radar apparatus 10 for processing a signal corresponding to the reflected radiation 60 from the region of interest (ROI) 20. In other words, in the listening interval, employing a CW tone and a de-chirped baseband signal will comprise not only the return of the CW-tone but also the interferences close to this CW tone, up to a maximum bandwidth of the baseband receiver section.
Optionally, the radar apparatus 10 employs an array of antenna elements for generating the interrogating radiation 50 for interrogating the region of interest (ROI) 20, and also an array of antenna elements for receiving the reflected radiation 60 from the ROI. Optionally, a same array of antenna elements if employed both for emitting the interrogating radiation 50 and also receiving the reflected radiation 60. Moreover, signal processing functions within the radar apparatus 10 are advantageously implemented using one or more fast processors to provide digital signal processing (DSP), for generating the interrogating radiation 50 and processing the received radiation 60; for example, the one or more fast processors are advantageously implemented as one or more reduced instruction set computers (RISC), or an array of such RISC. The one or more fast processors are operable to execute one or more software products, including computer instructions.
The radar apparatus 10 is capable of being used in many fields of application, for example: (i) for on-vehicle radar systems, for example for automatic vehicle braking systems and/or automatic vehicle steering systems; (ii) for monitoring safety-critical areas, for example railway level-crossings; (iii) for intruder alarm systems, for example for detecting unauthorized personnel; (iv) for airborne projectile guidance, for example high-velocity guided mortars; (v) for obstacle detection in automated agricultural equipment, for example automated combine harvesters, ploughing equipment, automated fruit picking apparatus, and so forth; (vi) for use on harbour ( harbor, US English) facilities, for example for guiding automated equipment for handling ship containers; and so forth.
Although use of embodiments of the present disclosure at electromagnetic radar radiation emission and reception frequencies in an order of 77 GHz is described in the foregoing, it will be appreciated that the radar apparatus 10 is optionally arranged to operate at radiation frequencies in a range of 30 GHz to 200 GHz, more optionally in a range of 50 GHz to 150 GHz, and yet more optionally in a range of 60GHz to 100 GHz.
The radar apparatus 10 is advantageously operable to avoid using test tones in the pulse train corresponding to a frequency of emission of the one or more interfering sources present in the region of interest (ROI, 20) as determined by the radar apparatus 10 during the listening period 80.
Modifications to embodiments of the invention described in the foregoing are possible without departing from the scope of the invention as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating", “consisting of”, “have", “is” used to describe and claim the present invention are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. Numerals included within parentheses in the accompanying claims are intended to assist understanding of the claims and should not be construed in any way to limit subject matter claimed by these claims.

Claims (13)

CLAIMS We claim:
1. . A radar apparatus (10) including an antenna arrangement for emitting interrogating radiation (50) to a region of interest (ROI, 20) and for receiving corresponding reflected radiation (60) from the region of interest (ROI, 20), and a signal processing arrangement (DSP) for generating signals for providing the interrogating radiation (50) and for processing received signals corresponding to the reflected radiation (60), characterized in that the radar apparatus (10) is operable to emit in the interrogating radiation (50) a plurality of CW tones for interrogating the region of interest (ROI, 20) and the signal processing arrangement (DSP) is operable to process the reflected radiation (60) to determine from CW tone information included in the reflected radiation (60) one or more objects in the region of interest (ROI, 20), and in a frequency interval between the CW tones (130) the radar apparatus (10) is operable to detect one or more interfering signals (120) being emitted from the region of interest (ROI, 20), and distinguish signal components arising from the one or more objects in the region of interest (ROI, 20) from the one or more interfering signals (120) based on the frequency of the emitted CW tones.
2. A radar apparatus (10) as claimed in claim 1, characterized in that the radar apparatus (10) is operable to detect at least one spatial range of at least one source (30) giving rise to the one or more interfering signals.
3. A radar apparatus (10) as claimed in claim 2, characterized in that the radar apparatus (1 0) is operable to compute the at least one spatial range by employing at least one triangulation measurement, and to apply a Kalman filter to measurement results of the at least one triangulation measurement.
4. A radar apparatus (10) as claimed in claim 3, characterized in that the Kalman filter is operable to employ a motion estimation of motion of the at least one source (30).
5. A radar apparatus (10) as claimed in any one of the preceding claims, characterized in that the radar apparatus (10) is operable to emit to, and receiver radiation from, the region of interest (ROI, 20) at an electromagnetic frequency range in a range of 30 GHz to 200 GHz, more optionally in a range of 50 GHz to 150 GHz, and yet more optionally substantially 77 GHz.
6. A radar apparatus (10) as claimed in any one of the preceding claims, characterized in that the radar apparatus (10) is arranged to interrogate the region of interest (ROI, 20), wherein the region of interest (ROI, 20) includes at least one of: (a) A railway crossing; (b) A region around a road vehicle onto which the radar apparatus (10) is mounted in operation; and (c) A region around a projectile onto which the radar apparatus (10) is mounted in operation
7. A method of using radar apparatus (10) including an antenna arrangement for emitting interrogating radiation (50) to a region of interest (ROI, 20) and for receiving corresponding reflected radiation (60) from the region of interest (ROI, 20), and a signal processing arrangement (DSP) for generating signals for providing the interrogating radiation (50) and for processing received signals corresponding to the reflected radiation (60), characterized in that the method includes: (i) operating the radar apparatus (10) to emit in the interrogating radiation (50) a plurality of CW to nes for interrogating the region of interest (ROI, 20); (ii) operating the signal processing arrangement (DSP) to process the reflected radiation (60) to determine from CW tone information included in the reflected radiation (60) one or more objects in the region of interest (ROI, 20); and (iii) in a frequ ency interval between the test tones (130) , the radar apparatus (10) is operable to detect one or more interfering signals (120) being emitted from the region of interest (ROI, 20), and distinguish signal components arising from the one or more objects from the one or more interfering signals (120) based on the frequency of the emitted CW tones.
8. A method as claimed in claim 7, characterized in that the method includes operating the radar apparatus (10) to detect at least one spatial range of at least one source (30) giving rise to the one or more interfering signals.
9. A method as claimed in claim 8, characterized in that the method includes operating the radar apparatus (10) to compute the at least one spatial range by employing at least one triangulation measurement, and to apply a Kalman filter to measurement results of the at least one triangulation measurement.
10. A method as claimed in claim 9, characterized in that the method includes using a Kalman filter that is operable to employ a motion estimation of motion of the at least one source (30).
11. A method as claimed in any one of claims 7 to 10, characterized in that the method includes operating the radar apparatus (10) to emit to, and receiver radiation from, the region of interest (ROI, 20) at an electromagnetic frequency range in a range of 30 GHz to 200 GHz, more optionally in a range of 50 GHz to 150 GHz, and yet more optionally substantially 77 GHz.
12. A method as claimed in any one of claims 7 to 11, characterized in that the method includes arranging tor the radar apparatus (10) to interrogate the region of interest (ROI, 20), wherein the region of interest (ROI, 20) includes at least one of: (a) a railway crossing; (b) a region around a road vehicle onto which the radar apparatus (10) is mounted in operation; and (c) a region around a projectile onto which the radar apparatus (10) is mounted in operation.
13. A computer program product comprising a non-transitory computerreadable storage medium having computer-readable instructions stored thereon, the computer-readable instructions being executable by a computerized device comprising processing hardware to execute a method as claimed in any one of claims 7 to 12.
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IL250253B (en) 2017-01-24 2021-10-31 Arbe Robotics Ltd Method for separating targets and clutter from noise in radar signals
IL255982A (en) 2017-11-29 2018-01-31 Arbe Robotics Ltd Detection, mitigation and avoidance of mutual interference between automotive radars
IL259190A (en) 2018-05-07 2018-06-28 Arbe Robotics Ltd System and method of fmcw time multiplexed mimo imaging radar using multi-band chirps
IL260694A (en) 2018-07-19 2019-01-31 Arbe Robotics Ltd Apparatus and method of two-stage signal processing in a radar system
IL260695A (en) 2018-07-19 2019-01-31 Arbe Robotics Ltd Apparatus and method of eliminating settling time delays in a radar system
IL260696A (en) 2018-07-19 2019-01-31 Arbe Robotics Ltd Apparatus and method of rf built in self-test (rfbist) in a radar system
IL261636A (en) 2018-09-05 2018-10-31 Arbe Robotics Ltd Skewed mimo antenna array for use in automotive imaging radar
IL271269A (en) 2019-12-09 2021-06-30 Arbe Robotics Ltd Radome for automotive radar patch antenna
CN111680737B (en) * 2020-06-03 2023-03-24 西安电子科技大学 Radar radiation source individual identification method under differential signal-to-noise ratio condition
CN116400316B (en) * 2023-06-02 2023-10-20 中国科学技术大学 Method for processing echo signals in radar mutual interference scene

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3389880B2 (en) 1999-03-30 2003-03-24 三菱電機株式会社 Radar equipment
JP2002174677A (en) 2000-12-08 2002-06-21 Mitsubishi Electric Corp Radar apparatus
DE50308888D1 (en) 2002-06-18 2008-02-07 Adc Automotive Dist Control METHOD OF IMPROVING STACKS IN SYSTEMS FOR OBJECT DETECTION
JP4007498B2 (en) * 2002-11-15 2007-11-14 三菱電機株式会社 Automotive radar equipment
SE525699C2 (en) 2003-05-05 2005-04-05 Saab Ab Device at radar operating at varying pulse repetition intervals
US7768445B2 (en) * 2004-08-02 2010-08-03 Mitsubishi Electric Corporation Frequency-modulated radar system with variable pulse interval capability
CN101089653B (en) 2007-07-20 2011-03-09 西安理工大学 Short-range frequency-modulation continuous wave FMCW radar anti-interference method
CA2762762C (en) 2008-05-29 2017-11-28 Cambridge Consultants Limited Radar system and method
EP2390679B1 (en) * 2010-05-27 2012-10-03 Mitsubishi Electric R&D Centre Europe B.V. Automotive radar with radio-frequency interference avoidance
FR2980853B1 (en) * 2011-09-30 2014-11-28 Thales Sa DEVICE FOR DETECTING AND LOCATING MOBILE EQUIPPED WITH RADARS AND ASSOCIATED METHOD
JP6176007B2 (en) 2013-09-06 2017-08-09 富士通株式会社 Detecting and ranging device

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