DE4235072C2 - Radar device with synthetic aperture based on rotating antennas - Google Patents

Radar device with synthetic aperture based on rotating antennas

Info

Publication number
DE4235072C2
DE4235072C2 DE4235072A DE4235072A DE4235072C2 DE 4235072 C2 DE4235072 C2 DE 4235072C2 DE 4235072 A DE4235072 A DE 4235072A DE 4235072 A DE4235072 A DE 4235072A DE 4235072 C2 DE4235072 C2 DE 4235072C2
Authority
DE
Germany
Prior art keywords
radar
function
width
amplitude
maximum
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.)
Expired - Fee Related
Application number
DE4235072A
Other languages
German (de)
Other versions
DE4235072A1 (en
Inventor
Horst Prof Dipl In Kaltschmidt
Helmut Dipl Ing Dr Klausing
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.)
Airbus Defence and Space GmbH
Original Assignee
Daimler Benz Aerospace AG
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 Daimler Benz Aerospace AG filed Critical Daimler Benz Aerospace AG
Priority to DE4235072A priority Critical patent/DE4235072C2/en
Publication of DE4235072A1 publication Critical patent/DE4235072A1/en
Application granted granted Critical
Publication of DE4235072C2 publication Critical patent/DE4235072C2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

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
    • G01S7/40Means for monitoring or calibrating
    • G01S7/4004Means for monitoring or calibrating of parts of a radar system
    • G01S7/4021Means for monitoring or calibrating of parts of a radar system of receivers
    • 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
    • G01S13/89Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/904SAR modes
    • 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
    • G01S13/89Radar or analogous systems specially adapted for specific applications for mapping or imaging
    • G01S13/90Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
    • G01S13/904SAR modes
    • G01S13/9082Rotating SAR [ROSAR]

Description

The invention relates to a radar device according to the preamble of the patent saying 1.

Such a radar device with a synthetic aperture based on rotating antennas (ROSAR) is known from DE-PS 39 22 086. The transmit and receive antennas are at the ends of a rotating arm, e.g. B. a helicopter rotor or one The turnstile is located above the rotor axis. The radar method with synthetic Aperture is based on the evaluation of the Doppler information for each individual point on the ground inside the real antenna lobe and therefore sets a relative movement ahead of the antenna and a pulsed coherent radar. The relative movement of the In the case of a ROSAR device, the antenna is rotated by the antenna generated with respect to the object to be detected. The received signal becomes pulse for Pulse with a set of reference functions derived from the lighting geometry cross-correlated, with a separate reference function for each distance interval must be generated.

With these reference functions it is initially assumed that the height of the antenna about the ground and the rotational speed of the antenna during the relevant measurement time are constant. Now it is a fact that helicopter rotor blades or generally rotating arms, like the turnstile above the rotor axis, through their Flexibility always have a surge and due to deformation during the Rotation even at the blade tips no constant speed of rotation over a full rotation prevails. For this reason is in the mentioned DE-PS 39 22 086th provided for the antenna in its area to determine a kinematic sensor the height and rotational speed fluctuations of the support arm and the reference function accordingly from the output signals of this kinematics sensor to correct them by taking them as constants in the reference functions  Sizes height and angular velocity can then be introduced as a variable. When Kinematic sensors, acceleration sensors are used, with the rotary speed fluctuations by simply integrating the signals of the Acceleration sensor divided by the rotor blade length can be detected. Doing so the uncorrected reference function from a distant point target with the angle α = 0 ° calculated.

If, as described in DE-PS 39 22 086, the correspondingly processed received signal is correlated with a single corrected reference function S Rk , the correlated result functions for point targets outside the angle α = 0 ° are no longer the full amplitude as the reference signal below reach the angle of rotation α = 0 °. The maximum of the result functions is also smeared or can no longer be separated from the signal noise. But point targets far from the angle of rotation α = 0 ° would no longer be detectable.

The invention has for its object in a radar device in question Way to show a way in which goals far outside of a reference goal in the rotational position α = 0 ° can be reliably detected.

This object is achieved by a radar device with the Features specified claims solved, advantageous Further training is the subject of the subclaims.

The idea of the invention now consists in the detection area of the radar device in split individual sectors and corrected for each of these sectors Define reference function. The width of the sectors is measured by Point aiming first with the help of a single, for the entire area of the Radar device corrected reference function made. Does that fall Maximum amplitude of a sideways from the reference target in the angle of rotation α = 0 ° point target below a certain percentage of the amplitude at Reference target or the signal width of this maximum exceeds a certain one Percentage of the corresponding width of the reference maximum, for one another sector determined a new reference function. Usually it is with one ROSAR device with antennas attached to the ends of a rotating arm be sufficient with a detection range of the radar device of 180 ° six sectors to be provided with a sector angle of 30 ° each.

The invention is explained in more detail in an exemplary embodiment with reference to the drawing. In this represent:

Figure 1 is a schematic block diagram of a ROSAR device according to the invention.

Fig. 2 is a sector representation of the detection area of the ROSAR device to explain the correction of the reference functions.

In Fig. 1, 1 is a transmitting antenna, 2 is a switch, 3 is a transmitter oscillator with Senderver and 4 is a clock. The transmission pulses generated by the transmission oscillator 3 are emitted in a clock-controlled manner by opening and closing the switch 2 via the transmission antenna 1 .

The transmission pulses are backscattered on objects and received by a transmission antenna 7 as reception signals. The received signal is fed as an intermediate frequency signal to a quadrature demodulator 8 and processed by quadrature mixing. The components of this processed signal are converted to analog / digital in an analog-digital converter 9 , stored in a memory 10 and fed to a correlator 11 . In the correlator, received signals from all distance intervals are cross-correlated with reference functions which are stored in a memory 12 . The reference functions are determined in a processor 13 for all distance intervals.

In Fig. 1, 14 is a kinematic sensor, for. B. uses an acceleration sensor with which fluctuations in rotational speed, ie deviations from the ideal angular frequency at the location of the antenna, are measured. The output signals of this sensor are fed to a correction calculation circuit 15 which calculates correction terms for individual sectors S e1 to S e7 which are fed to the processor 13 for the reference functions. How these corrections are determined is shown in FIG. 2.

The entire detection area of a ROSAR device, indicated by a small circle in the center, is shown schematically there, in this case a detection area of approximately 210 °. A reference point target 21 is located directly in the middle line of symmetry of the detection area, which, as described above, is measured, wherein only a correction value is used to correct the reference functions due to the variable speed of rotation of the rotor, which results from integration over a full revolution. The result function E detected with the radar device is shown schematically next to the reference point target 21 . This correlation function has a striking maximum with a reference amplitude AR and a relatively small reference width B R. Then this or another point target is brought into a different position and also measured with this corrected reference function. Once the maximum of the amplitude of the new result function is below a certain percentage, e.g. B. 75% of the reference amplitude falls, or if the width of the new amplitude a certain percentage, z. B. exceeds 125% of the reference width B R , a new correction of the reference functions is carried out for the subsequent angle range. This correction is made so that a point target, e.g. B. another point target shown in FIG. 2 with 22 in the Winkelhal-end of a sector, in this case the sector S e6 during the measurement leads to an equally sharp result function as the reference function E. In this case, the detection area of the radar device is divided into seven sectors, each at 30 °.

The received signals arriving at the radar device are then included in sectors correlates the rotation angle-specific reference functions, so that also sector-specific result functions arise.

Claims (3)

1. Radar device with a synthetic aperture, with at least one transmitting and receiving antenna (ROSAR) arranged on a rotating arm for transmitting successive transmission pulses and for receiving the backscattered transmission pulses as received signals, with devices for correlating the received signals with predetermined reference functions and with a kinematic sensor on rotating arm for determining the rotational speed fluctuations of the arm in the area of the antenna, the output signal of the kinematic sensor being used to correct the reference functions, characterized in that the detection area of the radar device is divided into individual sectors (Se1 to Se7) and a corrected reference function is established for each sector and the width of the sectors is carried out by measuring point targets ( 21 , 22 ) with the aid of a single corrected reference function valid for the entire detection range of the radar, the width of the sectors (Se1 b is Se7) from the measurement of several point targets ( 21 , 22 ) with the criterion that compared to a reference amplitude (AR) in the range of the maximum of a correlated reference result function (E) the amplitude of the correlated result function for a point target ( 22 ) Do not fall below the percent threshold or the width of the result function in the area of the maximum must not exceed a certain threshold.
2. Radar device according to claim 1, characterized in that then if the amplitude of the correlated result function for a point target below 75% of the reference amplitude drops, at this point the limit for one new sector is determined.  
3. Radar device according to claim 1 or 2, characterized in that then if the width of the result function for a point target is 125% of Width of the reference function (E) exceeds in the range of the maximum, the limit for a new sector is set.
DE4235072A 1992-10-17 1992-10-17 Radar device with synthetic aperture based on rotating antennas Expired - Fee Related DE4235072C2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE4235072A DE4235072C2 (en) 1992-10-17 1992-10-17 Radar device with synthetic aperture based on rotating antennas

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE4235072A DE4235072C2 (en) 1992-10-17 1992-10-17 Radar device with synthetic aperture based on rotating antennas

Publications (2)

Publication Number Publication Date
DE4235072A1 DE4235072A1 (en) 1994-04-21
DE4235072C2 true DE4235072C2 (en) 1995-09-28

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
DE4235072A Expired - Fee Related DE4235072C2 (en) 1992-10-17 1992-10-17 Radar device with synthetic aperture based on rotating antennas

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DE (1) DE4235072C2 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102014005107A1 (en) 2014-04-08 2015-10-08 Jürgen Hartmann Device for vibration frequency measurement of a tensioned drive belt and method for carrying out the vibration frequency measurement

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3430888C2 (en) * 1984-08-22 1988-10-06 Messerschmitt-Boelkow-Blohm Gmbh, 8012 Ottobrunn, De
DE3922086C1 (en) * 1989-07-05 1990-10-18 Messerschmitt-Boelkow-Blohm Gmbh, 8012 Ottobrunn, De

Also Published As

Publication number Publication date
DE4235072A1 (en) 1994-04-21

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Legal Events

Date Code Title Description
OP8 Request for examination as to paragraph 44 patent law
8127 New person/name/address of the applicant

Owner name: DAIMLER-BENZ AEROSPACE AKTIENGESELLSCHAFT, 80804 M

D2 Grant after examination
8364 No opposition during term of opposition
8327 Change in the person/name/address of the patent owner

Owner name: DAIMLERCHRYSLER AEROSPACE AKTIENGESELLSCHAFT, 8099

8320 Willingness to grant licences declared (paragraph 23)
8327 Change in the person/name/address of the patent owner

Owner name: DAIMLERCHRYSLER AEROSPACE AG, 85521 OTTOBRUNN, DE

8339 Ceased/non-payment of the annual fee