Kodi njira zitatu zosiyana za polarization za SAR ndi ziti?

1. Kodi SAR ndi chiyani?kugawanika kwa ndale?
Polarization: H horizontal polarization; V vertical polarization, ndiko kuti, kugwedezeka kwa mphamvu yamagetsi. Pamene satellite itumiza chizindikiro pansi, kugwedezeka kwa mafunde a wailesi omwe amagwiritsidwa ntchito kungakhale m'njira zambiri. Zomwe zikugwiritsidwa ntchito pano ndi izi:

Kugawa kwa malo ozungulira (H-horizontal): Kugawa kwa malo ozungulira kumatanthauza kuti pamene satelayiti itumiza chizindikiro pansi, njira yogwedera ya mafunde ake a wailesi imakhala yopingasa. Kugawa kwa malo ozungulira (V-vertical): Kugawa kwa malo ozungulira kumatanthauza kuti pamene satelayiti itumiza chizindikiro pansi, njira yogwedera ya mafunde ake a wailesi imakhala yopingasa.

Kutumiza kwa mafunde amagetsi kumagawidwa m'mafunde opingasa (H) ndi mafunde olunjika (V), ndipo kulandira kumagawidwanso m'magawo a H ndi V. Dongosolo la radar logwiritsa ntchito polarization yolunjika ya H ndi V limagwiritsa ntchito zizindikiro ziwiri kuyimira polarization yotumizira ndi kulandira, kotero likhoza kukhala ndi njira zotsatirazi—HH, VV, HV, VH.

(1) HH - yotumizira mauthenga mopingasa ndi kulandira mauthenga mopingasa

(2) VV - yotumizira mauthenga oyima ndi oyima komanso yolandirira mauthenga oyima

(3) HV - yotumizira mopingasa komanso yolandirira moyimirira

(4) VH - yotumizira mauthenga oyima ndi opingasa

Zosakaniza ziwiri zoyambirira za polarization izi zimatchedwa polarizations zofanana chifukwa transmit ndi receive polarizations ndizofanana. Zosakaniza ziwiri zomaliza zimatchedwa cross polarizations chifukwa transmit ndi receive polarizations zimakhala zofanana.

2. Kodi polarization imodzi, polarization iwiri, ndi polarization yonse mu SAR ndi chiyani?

Kugawika kwapadera kumatanthauza (HH) kapena (VV), zomwe zikutanthauza (kutumiza kopingasa ndi kulandira kopingasa) kapena (kutumiza kopingasa ndi kulandira kopingasa) (ngati mukuphunzira za radar ya nyengo, nthawi zambiri ndi (HH).)

Kugawa kwa magawo awiri kumatanthauza kuwonjezera njira ina yogawanitsira ku njira imodzi yogawanitsira, monga (HH) yopingasa yolumikizira ndi yopingasa yolandirira + (HV) yopingasa yolumikizira ndi yopingasa yolandirira.

Ukadaulo wathunthu wa polarization ndiye wovuta kwambiri, womwe umafuna kutumiza kwa H ndi V nthawi imodzi, ndiko kuti, njira zinayi za polarization za (HH) (HV) (VV) (VH) zilipo nthawi imodzi.

Makina a radar amatha kukhala ndi magawo osiyanasiyana a zovuta za polarization:

(1) Kugawanika kwa maginito amodzi: HH; VV; HV; VH

(2)Kugawanika kwa magawo awiri: HH+HV; VV+VH; HH+VV

(3) Kugawanikana kunayi: HH+VV+HV+VH

Ma radar a orthogonal polarization (monga full polarization) amagwiritsa ntchito ma polarization anayi awa ndipo amayesa kusiyana kwa gawo pakati pa ma channel komanso amplitude. Ma radar ena a dual-polarization amayesanso kusiyana kwa gawo pakati pa ma channel, chifukwa gawoli limagwira ntchito yofunika kwambiri pakuchotsa chidziwitso cha polarization.

Zithunzi za setilaiti ya radar Ponena za polarization, zinthu zosiyanasiyana zomwe zimawonedwa zimafalitsa mafunde osiyanasiyana a polarization kuti zigwirizane ndi mafunde osiyanasiyana a polarization. Chifukwa chake, kuzindikira kwakutali kwa mlengalenga kungagwiritse ntchito magulu angapo kuti kuwonjezere zomwe zili mu chidziwitso, kapena kugwiritsa ntchito polarizations zosiyanasiyana kuti ziwonjezere ndikuwonjezera kulondola kwa kuzindikira komwe kukufunidwa.

3. Kodi mungasankhe bwanji njira yolumikizirana ya satellite ya radar ya SAR?

Zochitika zikusonyeza kuti:

Pa ntchito za m'madzi, kugawanika kwa HH kwa gulu la L kumakhala kosavuta, pomwe kugawanika kwa VV kwa gulu la C kumakhala bwino;

Pa udzu ndi misewu yopapatiza pang'ono, polarization yopingasa imapangitsa zinthuzo kukhala ndi kusiyana kwakukulu, kotero SAR yogwiritsidwa ntchito pojambula malo imagwiritsa ntchito polarization yopingasa; pa nthaka yokhala ndi roughness yayikulu kuposa wavelength, palibe kusintha koonekeratu mu HH kapena VV.

Mphamvu ya echo ya chinthu chomwecho pansi pa ma polarization osiyanasiyana ndi yosiyana, ndipo kamvekedwe ka chithunzi nakonso ndi kosiyana, zomwe zimawonjezera chidziwitso chodziwira cholinga cha chinthucho. Kuyerekeza chidziwitso cha polarization yomweyo (HH, VV) ndi cross-polarization (HV, VH) kungawonjezere kwambiri chidziwitso cha chithunzi cha radar, ndipo kusiyana kwa chidziwitso pakati pa ma echo a polarization a zomera ndi zinthu zina zosiyana kumakhala kovuta kwambiri kuposa kusiyana pakati pa magulu osiyanasiyana.
Chifukwa chake, mu ntchito zenizeni, njira yoyenera yolumikizirana imatha kusankhidwa malinga ndi zosowa zosiyanasiyana, ndipo kugwiritsa ntchito bwino njira zingapo zolumikizirana kumathandiza kukonza kulondola kwa magulu a zinthu.