SE500809C2 - A method for scanning with coherent radar and a radar for carrying out the method - Google Patents

A method for scanning with coherent radar and a radar for carrying out the method

Info

Publication number
SE500809C2
SE500809C2 SE9300063A SE9300063A SE500809C2 SE 500809 C2 SE500809 C2 SE 500809C2 SE 9300063 A SE9300063 A SE 9300063A SE 9300063 A SE9300063 A SE 9300063A SE 500809 C2 SE500809 C2 SE 500809C2
Authority
SE
Sweden
Prior art keywords
antenna
radar
feeder
signals
reflector
Prior art date
Application number
SE9300063A
Other languages
Swedish (sv)
Other versions
SE9300063L (en
SE9300063D0 (en
Inventor
Jan Kjellgren
Gunnar Stenstroem
Original Assignee
Foersvarets Forskningsanstalt
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 Foersvarets Forskningsanstalt filed Critical Foersvarets Forskningsanstalt
Priority to SE9300063A priority Critical patent/SE500809C2/en
Publication of SE9300063D0 publication Critical patent/SE9300063D0/en
Priority to PCT/SE1994/000014 priority patent/WO1994016339A1/en
Publication of SE9300063L publication Critical patent/SE9300063L/en
Publication of SE500809C2 publication Critical patent/SE500809C2/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/12—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems
    • H01Q3/16—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems for varying relative position of primary active element and a reflecting device
    • H01Q3/20—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system using mechanical relative movement between primary active elements and secondary devices of antennas or antenna systems for varying relative position of primary active element and a reflecting device wherein the primary active element is fixed and the reflecting device is movable
    • 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
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/42—Simultaneous measurement of distance and other co-ordinates
    • G01S13/426—Scanning radar, e.g. 3D radar

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Aerials With Secondary Devices (AREA)

Abstract

The present invention relates to a method for scanning with a coherent radar and a radar for carrying out the method. The basic object of the invention is to get small mechanical mass movements and thereby in a simple way facilitate fast scanning cycles. This is solved according to the invention by a radar comprising a transmitter, an antenna system, a receiver and a signal processing equipment. Further, the radar is caracterized in that the antenna system comprises a physical antenna having a reflector surface (A) or antenna lens and a feed system arranged to successively direct radar signals towards and/or receive radar signals from different part surfaces ( DELTA A) of the antenna or lens and that the signal processing equipment is arranged to use coherent integration of received signals.

Description

500 809 över antennen. Genom variation av den koherenta integrationen kan oïika riktningar för antennen syntetiseras inom synfäitet, jämför figur 1. Med koherent förstås att utsänd vågform är så stabii att den reiativa fasen meiian många på varandra föijande radarpuiser (vâgformsperioder) kan utnyttjas för informationsextraktion. 500 809 over the antenna. Through variation of the coherent integration can different directions of the antenna are synthesized within the field of view, compare figure 1. By coherent is meant that the transmitted waveform is so stable that it reiativa phase meiian many consecutive radarpuiser (waveform periods) can be used for information extraction.

Radarmetoden kännetecknas ur mekanisk synvinkei främst av att antenn- systemet innehäiier en röriig subrefiektor eiier iins med vars hjäip matarens beiysning kontroiieras. Antennens apertur dimensioneras för att ge önskad siutiig uppiösning i vinkeiied och subrefiektor och matare dimensioneras så att önskat synfäit erhâiis. Synfäitet ges, om belysningen är fokuserad på refiektorytan, av den vinkei 0¿ som sub- refiektorn upptar sedd från aktueii deiyta på huvudrefiektorn. Matar- systemet kan bestå av ett horn och antingen en vridbar subrefiektor, en iins och en vridbar pianspegei eiïer en iins och ett vridbart prisma för sändning och mottagning eiier eventueiït enbart ena iedet.The radar method is characterized from a mechanical point of view mainly by the the system contains a movable subrefractor eiier iins with whose help the feed of the feeder is monitored. The aperture of the antenna is dimensioned for to give the desired siutiig resolution in the vinkeiied and subrefractor and feeders are dimensioned so that the desired visual acuity is obtained. Synfäitet ges, om the lighting is focused on the reflector surface, of the vinkei 0¿ which sub- the reflector occupies seen from the actual surface of the main reflector. Matar- the system may consist of a horn and either a rotatable sub-reflector, an iins and a rotatable pianspegei eiïer an iins and a rotatable prism for transmission and reception eiier eventueiït only one iedet.

Subrefiektorn eiier motsvarande, som förbinder matare och antenn, kan vara en eiiipsoidformad refiektor med mataren respektive aktueii dei av antennytan i vardera brännpunkten för eiiipsoiden. Vid röreise- mönster med varierande avstånd ti11 oiika deiar av antennytan reia- teras ena brännpunkten på iämpiigt sätt tiii ytan.The sub-reflector eiier equivalent, which connects feeder and antenna, can be an eiiipsoid-shaped reflector with the feeder respectively aktueii dei of the antenna surface at each focal point of the eiiipsoid. When traveling patterns with varying distances to 11 different diameters of the antenna surface one focal point is appropriately attached to the surface.

Avsökning i vinkeiied âstadkommes genom att subrefiektorn eïier mot- svarande roteras omkring matarens symmetriaxei eiier boresight. Vid en fast cirkuiärsymmetrisk och cirkuiärpoiariserad matare ger rotation runt matarens boresight en beiysning av subrefiektorn som är oberoende eiier reiativt oberoende av rotationsvinkein.Scanning in the veneer is accomplished by the subrefractor correspondingly rotated about the feeder's symmetriaxei eiier boresight. By a fixed circularly symmetrical and circularly polarized feeder provides rotation around the feeder's boresight a beysning of the subrefector which is independent eiier reiativt independent of rotational angle.

I figur 2 sammanfaiier antennsystemets boresight med vridningsaxein (i papperets pian) och den beiysta deiaperturen 41A kommer vid rotation att beskriva en cirkeiröreise som aistrar en ringformad antenn för t.ex. avsökning inom en kon. Ligger vridningsaxein vinkeirätt mot boresight aistras en iångsmai antenn för t.ex. sektorspaning.In Figure 2, the drilling sight of the antenna system coincides with the axis of rotation (i the paper pian) and the assisted diaperture 41A comes on rotation to describe a circular orbit traveling to a ring-shaped antenna for example scanning within a cone. Is the torsion axis right at the right angle boresight aistras an iångsmai antenna for e.g. sector reconnaissance.

Metoden kännetecknas vad det gäiier signaibehandiing av att den om- fattar ett fiertai deimätningar där varje deimätning endast utnyttjar en iiten dei av huvudantennens yta. Meiian deimätningarna växias sedan den beiysta deien av antennytan så att heia ytan biir beiyst då aiïa 500 809 deïmätningar utförts. Önskad hög uppïösning inom synfäïtet fås genom att i signaibehandïingen koherent integrera signaïerna via aïia små deïytor på he1a antennen. Denna signaibehandiing omfattar i första hand integration av signaier från oïika riktningar (syntetisk vridning av antennen). Om mätavstânden befinner sig inom antennens närfäït krävs en integration som kombinerar riktning och avstånd (syntetisk vridning och fokusering av antennen).The method is characterized in terms of signal processing in that it takes a fiertai deim measurements where each deim measurement only uses a small amount of the surface of the main antenna. Meiian day measurements are then grown the beiysta dei of the antenna surface so that the whole surface biir beiyst then aiïa 500 809 deï measurements were performed. The desired high resolution within the visual field is obtained through to coherently integrate the signals via the small ones in the signal processing deïytor on the he1a antenna. This signaibehandiing includes in the first hand integration of signals from different directions (synthetic rotation of the antenna). If the measuring distances are within the vicinity of the antenna requires an integration that combines direction and distance (synthetic rotation and focusing of the antenna).

Signaibehandiingen kan ske med metoder som är kända i samband med användningen av radar med syntetisk apertur. Tiiïämpningen av dessa stä11er inte fackmannen pâ omrâdet inför nâgra specie11a probïem, varför signaïbehandiingen inte behandïas fuiïständigt här. Dock ska11 ski11naden me11an den kända apertursyntestekniken, SAR, och föreiigg- ande uppfinning understrykas här, eftersom iikheten i signaïbehandïing påpekats. Vid SAR sänder en antenn radarsignaier och mottager dem under det att antennen och den farkost som bär den utför en vanïigen ïinjär röreise. Antennen är riktad åt sidan sett i antennens rörelse- riktning. Signaïbehandïingen syntetiserar sedan en - kanske kiïometer- iång - radarapertur. I föreïiggande fa11 användes en vaniig fysisk antenn, som bringas att sända och mottaga radarsignaier med hjä1p av deiytor hos antennen. Signaïbehandïingen syntetiserar sedan en antenn baserad på heia den fysiska antennens yta.Signa treatment can be done with methods that are known in connection with the use of radar with synthetic aperture. The application of these does not pose any specific problems in the art to those skilled in the art, why signaïbehandiingen is not treated fully here. However, ska11 The difference between the known aperture synthesis technology, SAR, and the The present invention is emphasized here, since the similarity in signal processing pointed out. At SAR, an antenna sends radar signals and receives them while the antenna and the vehicle carrying it perform a vanïigen ïinjär röreise. The antenna is directed to the side as seen in the movement of the antenna. direction. The signaling treatment then synthesizes a - perhaps chiiometer- iång - radar aperture. In the present case, a common physical is used antenna, which is caused to transmit and receive radar signals using deiytor at the antenna. The signal processing then synthesizes an antenna based on the surface of the physical antenna.

Metodens resuïterande vinkeïupplösning ges av antennens aperturdimen- sioner dl x dz eïler aperturyta A. Om både sändning och mottagning sker via succesivt vaïda deiytor erhâ11s en upplösning zxíl som är fyra gånger bättre än för en konventioneïi antenn. Detta beror på att sändningen via en viss deiyta kan koppias ti11 mottagningen av samma de1yta.The resulting angular resolution of the method is given by the aperture dimension of the antenna. sions dl x dz eïler aperturyta A. About both transmission and reception takes place via successively vaïda deiytor is obtained a resolution zxíl which is four times better than for a conventional antenna. This is because the transmission via a certain dei surface can be copied to the reception of the same de1yta.

Vinkeïuppiösningen Anïl för aperturytan A ges av \2 _/ ¿Sl]_ = I-Ä .The vinyl solution Anïl for aperture surface A is given by \ 2 _ / ¿Sl] _ = I-Ä.

Den önskade uppïösningen får avvägas mot främst nackdeien med en fy- siskt stor antenn. En fast e11er eventue11t iängsamt vridbar antenn G1 00 "J f9 bör dock medge att en större antenn kan användas jämfört med en kon- ventionellt mekaniskt avsökande antenn.The desired solution may be weighed against mainly the neck dough with a large antenna. A fixed or possibly slowly rotating antenna G1 00 "J f9 should, however, allow a larger antenna to be used compared to a con- conventional mechanical scanning antenna.

Synfältet CL ges av storleken på den belysta antennytan med våglängden som mått. Ett stort synfält leder till mindre och fler elementar- antenner för en given antennyta. Synfältets lobvinkel för en belyst area ÅA fås till Q Åz :FV Antalet bildelement NA¿¿i vinkelled ges av förhållandet mellan synfält och upplösning enligt nedan.The field of view CL is given by the size of the illuminated antenna surface with the wavelength as a measure. A large field of view leads to smaller and more elementary antennas for a given antenna surface. The field of view of the field of view for an illuminated area ÅA is available Q Åz : FV The number of pixels NA¿¿i angular is given by the ratio of field of view and resolution as below.

N = Q ASL A_Q_' Bildstorlek eller antal bildelement i vinkelled avväges främst mot periodtid för en avsökning Tavs eller bildfrekvens favs. Bildfrekven- sen är vidare beroende av vågformens repetitionsfrekvens fprf eller maximalt entydigt mätavstând. Simultan observation med flera elemen- tarantenner narray ökar prestanda men komplicerar systemet. I extrem- fallet erhålls en komplett gruppantenn inklusive elementarmottagare, dvs grunden till en s.k. digital antenn. För varje elementarantenn kan flera mätningar utföras n¿¿A, vilket förbättrar integrationsfaktorn och möjliggör dopplersignalbehandling men samtidigt medför ökad obser- vationstid Tobs. Observationstiden beror av faktorerna narray, n¿¿A, fprf eller maximalt entydigt mätavstând Rma samt antalet bildelement x i vinkelled N¿&¿¿ enligt följande “ANNAQ prf'narray I _, _ C där fprf ' É7É___ ' Vid avsökning kan normalt tiden ej helt utnyttjas för observation utan en viss s.k. dödtid Td tillkommer genom att realiserade metoder av- viker från de ideala så att 500 809 Tavs = Tobs + Td ' Förhållandet mellan observationstid och avsökningstid för en avsök- ningsperiod ges av kvoten k, k 5 l, enligt k = Tobs 'avs ! där radarmetodens potentiella bildfrekvens fbi1d fås till fbnd = TL' ' avs Radarmetodens mätdimensioner kan utöver två vinkeldimensioner och avstånd, dvs spatiellt 3-dimensionell observation, också utgöras av kombinationer av enbart en vinkel och avstånd.N = Q ASL A_Q_ ' Picture size or number of picture elements in angular direction is weighed mainly against period time for a scan Silent or frame rate favs. Image frequency then is further dependent on the waveform repetition frequency fprf or maximum unambiguous measuring distance. Simultaneous observation with several elements Tarantula narray increases performance but complicates the system. In the extreme In this case, a complete group antenna including element receivers is obtained, ie the basis of a so-called digital antenna. For each elemental antenna can several measurements are performed now, which improves the integration factor and enables Doppler signal processing but at the same time leads to increased vation time Tobs. The observation time depends on the factors narray, nÿA, fprf or maximum unambiguous measuring distance Rma and the number of pixels x in angle N¿ & ¿¿as follows “ANNAQ prf'narray IN _, _ C where fprf 'É7É ___' When scanning, the time can normally not be fully used for observation without a certain s.k. dead time Td is added by realized methods deviates from the ideal so that 500 809 Tavs = Tobs + Td ' The relationship between observation time and scan time for a scan period is given by the ratio k, k 5 l, according to k = Tobs 'avs ! where the potential frame rate fbi1d of the radar method is obtained fbnd = TL '' avs The measuring dimensions of the radar method can in addition to two angular dimensions and distance, ie spatial 3-dimensional observation, also consists of combinations of only one angle and distance.

För att integrationen av alla signaler som tillhör en avsökning skall kunna utföras, måste förändringar i mätgeometrin vara mer eller mindre kända under avsökningstiden. I enklaste fall förutsätts oförändrad, fix mätgeometri eller linjär rörelse relativt den antennapertur som genereras under avsökningen. Radarmetodens observationstid Tobs och våglängd »Ä bestämmer hastighetsgränsen Vre1 mellan fixt och rörligt objekt och accelerationsgränsen are] mellan linjär och icke linjär rörelse. Uttryck för dessa gränser kan med en viss grad av godtyck- lighet anges enligt nedan. Å Villkor för fixt objekt vreï 5 äT-- . obs V. N _ M. Ü )\ illkor for linJar rorelse are] 5 -ï- . 4T obs Särskilt det första men även det andra villkoret ovan är exempel på ansatser för att förenkla invertering av mätdata vid SAR-metoder.In order for the integration of all signals belonging to a scan to can be performed, changes in the measurement geometry must be more or less known during the scan time. In the simplest case, unchanged is assumed, fix measurement geometry or linear motion relative to the antenna aperture that generated during the scan. Radar method observation time Tobs and wavelength »Ä determines the velocity limit Vre1 between fixed and variable objects and the acceleration limit are] between linear and non-linear movement. Expressions of these limits can, with a certain degree of arbitrariness, is indicated below. Oh Conditions for fixed objects vreï 5 äT--. obs V. N _ M. Ü) \ illkor for linJar rorelse are] 5 -ï-. 4T obs Especially the first but also the second condition above are examples of approaches to simplify the inversion of measurement data by SAR methods.

I det följande skissas mera konkret en mekanisering av avsökningen i två fall, dels en volymetrisk avsökning av en konisk rymdvinkel och dels en ytavsökning inom en begränsad vinkelsektor. 500 809 Avsökning av en konisk rymdvinkel kan ske genom att en liten delantenn med en konformad bred antennlob får rotera i en cirkelbana med stor diameter. Delantennens boresight anordnas så att denna blir parallell med cirkelbanans symmetriaxel som därmed ger observationsriktningen.In the following, a more concrete mechanization of the scan in two cases, a volumetric scan of a conical angle of view and and a surface scan within a limited angular sector. 500 809 Scanning of a conical space angle can be done by a small sub-antenna with a cone-shaped wide antenna lobe allowed to rotate in a circular orbit with large diameter. The boresight of the sub-antenna is arranged so that it is parallel with the axis of symmetry of the circular path which thus gives the direction of observation.

Antennens rotation i cirkelbanan utförs genom att man med en roterande spegel eller ett linsarrangemang avlänkar och fokuserar strålningen för belysning av en cirkelformad reflektor. Denna kan vara ett utsnitt av en parabol- eller konformad yta.The rotation of the antenna in the circular path is performed by using a rotary mirror or lens arrangement deflects and focuses the radiation for illumination of a circular reflector. This can be a section of a dish or cone-shaped surface.

Sektoravsökning av en yta inom en begränsad vinkel kan ske genom att en liten delantenn med en konformad bred antennlob får genomlöpa en approximativt rak aperturbana med stor utsträckning. Rörelsen åstad- kommes med hjälp av en ellipsoidformad subreflektor som roteras och samtidigt belyser en parabolformad huvudreflektor. Rotationsaxeln anordnas så att den är vinkelrät mot observationsriktningen och går genom huvudreflektorns fokus. Mataren är placerad med rotationsaxeln som symmetriaxel för att ge en likformig belysning av subreflektorn för olika vridningsvinklar. Synfältet ges approximativt av synvinkeln under vilken subreflektorn syns frân reflektorn. Ett fast avstånd från rotationsaxeln till strâlningens fokus innebär att fokus kan förläggas till huvudreflektorns yta i högst tvâ punkter som i sådana fall är symmetriskt belägna omkring det plan som definieras av parabolaxeln och subreflektorns rotationsaxel. I övrigt kommer subreflektorn att fokusera strålningen på ett litet avstånd från reflektorytan. Syn- fältet åstadkommes genom ett koniskt strålknippes reflektion men i detta fall sker reflektionen i allmänhet ej i strâlknippets skärnings- punkt utan olika riktningar reflekteras i olika punkter på reflektor- ytan. Genom att reflektorytan är krökt kommer synfältet att pâverkas och reduceras vid utvridning av det belysande strâlknippet från para- bolens axel. Denna oönskade variation av synfältet kan betraktas som en reduktion av antennens effektivitet. Antennen kan beräknas klara utvridningar på ca 3 60°.Sector scanning of a surface within a limited angle can be done by a small sub-antenna with a cone-shaped wide antenna lobe may pass through one approximately straight aperture orbit to a large extent. The movement is obtained by means of an ellipsoidal sub-reflector which is rotated and at the same time illuminating a satellite dish-shaped main reflector. The axis of rotation arranged so that it is perpendicular to the direction of observation and goes through the focus of the main reflector. The feeder is positioned with the axis of rotation as an axis of symmetry to give a uniform illumination of the sub-reflector for different angles of rotation. The field of view is given approximately by the point of view below which the sub-reflector is visible from the reflector. A fixed distance from the axis of rotation of the radiation focus means that the focus can be shifted to the surface of the main reflector at a maximum of two points which in such cases are symmetrically located around the plane defined by the parabolic axis and the axis of rotation of the sub-reflector. Otherwise, the sub-reflector will focus the radiation at a small distance from the reflector surface. Sight- the field is produced by the reflection of a conical beam but in in this case the reflection generally does not take place in the intersection of the beam point without different directions is reflected in different points on the surface. Because the reflector surface is curved, the field of view will be affected and is reduced when the illuminating beam is extended from the bolens axel. This unwanted variation of the field of view can be considered as a reduction in the efficiency of the antenna. The antenna can be calculated ready rotations of about 3 60 °.

Claims (9)

500 809 Patentkrav:500 809 Patent claims: 1. En metod för avsökning av ett omrâde med hjäip av radar, k ä n - n e t e c k n a d a v att radarsigna1er succesivt utsänds och/eller mottages via oiika deiytor (¿3A) av en antennyta (A) eiïer antennïins hos en fysisk antenn och att vinkeïuppïösningen hos antennens synfäit (Il ) åstadkommes genom koherent integration av mottagna signaier.A method of scanning an area by means of radar, characterized in that radar signals are successively transmitted and / or received via different surfaces (¿3A) of an antenna surface (A) or antennas of a physical antenna and that the angular resolution of the visual acuity (II) of the antenna is achieved by coherent integration of received signals. 2. En radar för avsökning av ett omrâde innefattande en sändare, ett antennsystem, en mottagare och en signaibehandiingsutrustning, k ä n- n e t e c k n a d a v att antennsystemet innefattar en fysisk antenn med en refïektoryta (A) eiier antenniins och ett matarsystem anordnat att succesivt rikta radarsignaier mot och/e11er mottaga radarsignaier från o1ika deiytor (¿1A) hos antennen e11er iinsen och att signai- behandiingsutrustningen är anordnad att använda koherent integration av mottagna signaler.A radar for scanning an area comprising a transmitter, an antenna system, a receiver and a signal processing equipment, characterized in that the antenna system comprises a physical antenna with a reflector surface (A) or antenna and a feed system arranged to successively direct radar signals towards and / or receiving radar signals from different surfaces (¿1A) of the antenna or the signaling equipment and that the signal processing equipment is arranged to use coherent integration of received signals. 3. En radar enïigt patentkravet 2, k ä n n e t e c k n a d a v att matarsystemet består av en fast matare (1) och en vridbar subrefiektor (2).A radar according to claim 2, characterized in that the feed system consists of a fixed feeder (1) and a rotatable sub-reflector (2). 4. En radar enïigt patentkravet 2, k ä n n e t e c k n a d a v att matarsystemet består av en fast matare (1), en matarïins och en vrid- bar pianspegei.A radar according to claim 2, characterized in that the feeder system consists of a fixed feeder (1), a feeder and a rotatable pliers mirror. 5. En radar eniigt patentkravet 2, k ä n n e t e c k n a d a v att matarsystemet består av en fast matare (1), en matariins och ett vrid- bart prisma.A radar according to claim 2, characterized in that the feeder system consists of a fixed feeder (1), a feeder and a rotatable prism. 6. En radar eniigt patentkravet 3, k ä n n e t e c k n a d a v att subrefiektorn (2) är eïiipsoidformad och anordnad att ha mataren (1) och aktue11 dei ( AA) av huvudantennens refiektionsyta (A) i vardera brännpunkten.A radar according to claim 3, characterized in that the sub-reflector (2) is electroidally shaped and arranged to have the feeder (1) and the current (AA) of the reflection surface (A) of the main antenna at each focal point. 7. En radar eniigt något av patentkraven 2-6, k ä n n e t e c k - n a d a v att matarsystemets vridningsaxei (3) sammanfaiïer med antennsystemets symmetriaxeï. 500 8 Û 9A radar according to any one of claims 2-6, characterized in that the axis of rotation (3) of the feeder system coincides with the axis of symmetry of the antenna system. 500 8 Û 9 8. En radar enhgt något av patentkraven 2-6, k ä n n e t e c k - n a d a v att matarsystemts vridningsaxeï (3) är vinkeïrät mot antennsystemets symmetríaxeï.A radar according to any one of claims 2-6, characterized in that the axis of rotation (3) of the feeder system is perpendicular to the axis of symmetry of the antenna system. 9. En radar enhgt något av patentkraven 2-8, k ä n n e t e c k - n a d a v att matarsystemet är anordnat att, i varje ögonbhck, rikta radarsignaïer mot och/e11er mottaga radarsignaler från två eHer Hera deïytor (AA) på antennen.A radar according to any one of claims 2-8, characterized in that the feeder system is arranged to, at any moment, direct radar signals towards and / or receive radar signals from two or more surfaces (AA) on the antenna.
SE9300063A 1993-01-12 1993-01-12 A method for scanning with coherent radar and a radar for carrying out the method SE500809C2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
SE9300063A SE500809C2 (en) 1993-01-12 1993-01-12 A method for scanning with coherent radar and a radar for carrying out the method
PCT/SE1994/000014 WO1994016339A1 (en) 1993-01-12 1994-01-12 A method for scanning with a coherent radar and a radar for carrying out the method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE9300063A SE500809C2 (en) 1993-01-12 1993-01-12 A method for scanning with coherent radar and a radar for carrying out the method

Publications (3)

Publication Number Publication Date
SE9300063D0 SE9300063D0 (en) 1993-01-12
SE9300063L SE9300063L (en) 1994-07-13
SE500809C2 true SE500809C2 (en) 1994-09-05

Family

ID=20388509

Family Applications (1)

Application Number Title Priority Date Filing Date
SE9300063A SE500809C2 (en) 1993-01-12 1993-01-12 A method for scanning with coherent radar and a radar for carrying out the method

Country Status (2)

Country Link
SE (1) SE500809C2 (en)
WO (1) WO1994016339A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19801511C2 (en) * 1998-01-16 2001-12-06 Wieland Werke Ag Process for contour detection using microwaves and device for carrying out the process
EP2773978A1 (en) * 2011-10-31 2014-09-10 Raytheon Company Methods and apparatus for wide area synthetic aperture radar detection
CN112319849B (en) * 2021-01-07 2021-04-09 北京天创凯睿科技有限公司 Method for detecting surface damage of aircraft air inlet

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4042933A (en) * 1976-03-19 1977-08-16 The United States Of America As Represented By The Secretary Of The Navy Antenna line scan system for helicopter wire detection
FR2445040A1 (en) * 1978-12-22 1980-07-18 Thomson Csf CONICAL SCANNING ANTENNA FOR RADAR, ESPECIALLY TRACKING RADAR
US4668955A (en) * 1983-11-14 1987-05-26 Ford Aerospace & Communications Corporation Plural reflector antenna with relatively moveable reflectors
US4992796A (en) * 1990-02-20 1991-02-12 Lockheed Sanders, Inc. Computed-interferometry radar system with coherent integration

Also Published As

Publication number Publication date
SE9300063L (en) 1994-07-13
SE9300063D0 (en) 1993-01-12
WO1994016339A1 (en) 1994-07-21

Similar Documents

Publication Publication Date Title
Kingsley et al. Understanding radar systems
US5381151A (en) Signal processing for ultra-wideband impulse radar
US4723124A (en) Extended SAR imaging capability for ship classification
US4989008A (en) Spotlight mapping radar system
US4855747A (en) Method of target imaging and identification
CN86103423A (en) Work in the radar system of two frequency ranges
RU96115330A (en) DEVICE FOR COMPENSATION OF MOTION ERRORS FOR RADARS WITH A SYNTHESIZED Aperture BASED ON ROTATING ANTENNA (ROSAR) FOR HELICOPTERS
US4305075A (en) Conically scanning antenna system for tracking radars
US6670920B1 (en) System and method for single platform, synthetic aperture geo-location of emitters
EP0344272B1 (en) Sar signal azimuth ambiguity cancellation
US4558594A (en) Phased array acoustic antenna
US4353073A (en) Antenna arrangement for a radar surveillance method for target locating with altitude acquisition
US4536763A (en) On-board orientation device for aircraft
SE500809C2 (en) A method for scanning with coherent radar and a radar for carrying out the method
RU2316021C2 (en) Multichannel radar system of flight vehicle
US3916407A (en) Doppler navigation system with angle and radial velocity determination
JP3035351B2 (en) Radar equipment
JP2730296B2 (en) Ground mapping radar signal processing method and apparatus
US3331072A (en) System and method for surveillance, tracking and communicating
KR102188596B1 (en) Radar using array antenna rotation and method for acquiring 3d image thereof
JPS60170777A (en) Synthetic aperture radar
JPS63501443A (en) Improvements in or relating to radar systems
Bai et al. DOA Estimation Using Shipborne HFSWR Based on Virtual Synthetic Array
US4010472A (en) Antenna scanning apparatus
JPH03179282A (en) Bistatic radar apparatus