A.M. Tarasenko - Engineer, JSC «Concern «VEGA». E-mail: asianna@list.ru

Sounding signal modulating function search and its further implementation is an important step of spaceborne SAR development. Signal-code sequence choice implies on response function appearance, the response function being the criterion of SAR performances such significant as spatial resolution, radiometric and power characteristics. The work consists in searching of proper sounding signal forming method to obtain better image quality without significant complications of schematic. The image of a single point target, or the response function, has been analyzed - in particular, main lobe width at 3 dB level, peak and integral sidelobe ratio, and sidelobe distribution in the image. Combination of maximum length sequences provides a variety of modulating functions with new properties, while the chirp is well-studied, and just a few modulation patterns can be built on its base. That-s why the most part of the work is devoted to maximum length sequence combination as a technique of sounding signal building. The algorithms of sounding signal forming proposed in the paper are considered worth to be implemented in spaceborne SAR modulator developing. For example, the investigation of sounding signal building techniques based on a single M-sequence has shown the case of sequence cyclic shift by a random step number to provide extra sidelobe compression up to 35 dB at constant signal base.

 

1. Neronskijj L.B., Mikhajjlov V.F., Bragin I.V. Mikrovolnovaja apparatura distancionnogo zondirovanija poverkhnosti Zemli i atmosfery. Radiolokatory s sintezirovannojj aperturojj antenny. Ucheb. posobie. SPb.: SPbGUAP. 1999. CH. 2.
2. Kondratenkov G.S., Frolov A.JU. Radiovidenie. Radiolokacionnye sistemy distancionnogo zondirovanija zemli. Ucheb. posobie dlja vuzov / Pod red. G.S. Kondratenkova. M.: Radiotekhnika. 2005.
3. Lepjokhina T.A., Los V.O., Tarasenko A.M. Vybor parametrov zondirujushhego signala kosmicheskogo RSA po rezultatam issledovanijj kharakteristik funkcii otklika na odinochnuju tochechnuju cel // Materialy X Vseros. nauch.-tekhn. konf. «Nauchnye chtenija po aviacii, posvjashhjonnye pamjati N.E. ZHukovskogo». Moskva. 2013.
4. Lepjokhina T.A., Semjonov M.A., Tarasenko A.M. Modelirovanie i obrabotka radiogologramm dlja ocenki osnovnykh kharakteristik radiolokatora s sintezirovannojj aperturojj / Materialy nauch.-tekhn. konf. «Sistemy nabljudenija, monitoringa i distancionnogo zondirovanija Zemli». M.: MNTOREHS im. A.S. Popova. 2008. S. 154-157.
5. Lepjokhina T.A., Nikolaev V.I., Tarasenko A.M.Issledovanie statistiki bokovykh lepestkov funkcii otklika RSA s zondirujushhim signalom, modulirovannymM‑posledovatelnostju, dlja opredelenija shumovogo ehkvivalenta / Materialy nauch.-tekhn. konf. «Sistemy nabljudenija, monitoringa i distancionnogo zondirovanija Zemli». M.: MNTOREHS im. A.S. Popova. 2010.
6. Kudrja A.I., Tolstov E.F., CHetverik V.N. Rasshirenie vozmozhnostejj ispolzovanija M‑posledovatelnosti v RSA. II Vserossijjskie Armandovskie chtenija [EHlektronnyjj resurs]: Radiofizicheskie metody v distancionnom zondirovanii sred / Materialy V Vseros. nauch. konf. Murom: poligraficheskijj centr MI VlGU. 2012.
7. Tarasenko A.M. Vybor sposoba postroenija ansamblejj M-posledovatelnostejj dlja moduljacii zondirujushhego signala kosmicheskogo RSA s celju umenshenija maksimalnogo urovnja bokovykh lepestkov funkcii otklika na odinochnuju tochechnuju cel // Materialy 20-jj Mezhdunar. Krymskojj konf. «SVCH-tekhnika i telekommunikacionnye tekhnologii». KryMiKo. 2014.