Kodi mitundu itatu yosiyana ya polarization ya SAR ndi iti?

1. Kodi SAR ndi chiyanipolarization?
Polarization: H yopingasa polarization; V vertical polarization, ndiko kuti, kugwedezeka kwa gawo la electromagnetic field. Pamene setilaitiyo itumiza chizindikiro pansi, njira yogwedezeka ya mafunde a wailesi yomwe imagwiritsidwa ntchito ikhoza kukhala m'njira zambiri. Zomwe zimagwiritsidwa ntchito pano ndi:

Horizontal polarization (H-horizontal): Horizontal polarization kumatanthauza kuti satellite ikatumiza chizindikiro pansi, kugwedezeka kwa mafunde a wailesi yake kumakhala kopingasa. Vertical polarization (V-vertical): Vertical polarization imatanthawuza kuti pamene satellite itumiza chizindikiro pansi, kugwedezeka kwa kayendedwe ka wailesi yake kumakhala koyima.

Electromagnetic wave transmission imagawidwa m'mafunde opingasa (H) ndi mafunde ofukula (V), ndipo kulandirira kumagawidwanso mu H ndi V. Dongosolo la radar pogwiritsa ntchito H ndi V linear polarization limagwiritsa ntchito zizindikiro zoimira polarization yotumizira ndi kulandira, kotero ikhoza kukhala ndi njira zotsatirazi-HH, VV, HV, VH.

(1) HH - kwa kufala yopingasa ndi yopingasa kulandira

(2) VV - kwa kufala ofukula ndi kulandira ofukula

(3) HV - kwa kufala yopingasa ndi ofukula kulandira

(4) VH - kwa ofukula kufala ndi yopingasa kulandira

Mitundu iwiri yoyambirira ya polarization imatchedwa polarizations yofananira chifukwa kutumizirana ndi kulandira polarizations ndizofanana. Zophatikizira ziwiri zomaliza zimatchedwa cross polarizations chifukwa chotumizira ndi kulandira polarizations ndi orthogonal wina ndi mnzake.

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

Single polarization imatanthawuza (HH) kapena (VV), kutanthauza (kufalikira kopingasa ndi kulandirira kopingasa) kapena (kutumiza molunjika ndi kulandila kolowera) (ngati mukuphunzira gawo la meteorological radar, nthawi zambiri ndi (HH).

Dual polarization amatanthauza kuwonjezera njira ina ya polarization ku njira imodzi ya polarization, monga (HH) kupatsirana kopingasa ndi kulandirira kopingasa + (HV) kufalikira kopingasa ndi kulandila kolowera.

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

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

(1) Polarization imodzi: HH; VV; HV; VH

(2)Dual polarization: HH+HV; VV + VH; HH+VV

(3) Polarizations anayi: HH+VV+HV+VH

Orthogonal polarization (ie polarization yathunthu) ma radar amagwiritsa ntchito polarizations anayiwa ndikuyesa kusiyana kwa magawo pakati pa mayendedwe komanso matalikidwe. Ma radar ena apawiri-polarization amayesanso kusiyana kwa magawo pakati pa mayendedwe, chifukwa gawoli limagwira ntchito yofunikira pakuchotsa zidziwitso za polarization.

Zithunzi za setilaiti ya radar Pankhani ya polarization, zinthu zosiyanasiyana zowonedwa zimabalalitsa mafunde osiyanasiyana a polarization pamafunde osiyanasiyana. Chifukwa chake, zowonera patali zitha kugwiritsa ntchito magulu angapo kuti ziwonjezere zambiri, kapena kugwiritsa ntchito ma polarizations osiyanasiyana kuti zithandizire ndikuwongolera kulondola kwazomwe mukufuna.

3. Mungasankhe bwanji polarization mode ya SAR radar satellite?

Zochitika zikuwonetsa kuti:

Kwa ntchito zam'madzi, HH polarization ya L band imakhala yovuta kwambiri, pamene VV polarization ya C band ili bwino;

Kwa udzu wobalalika pang'ono ndi misewu, polarization yopingasa imapangitsa kuti zinthu zikhale ndi kusiyana kwakukulu, kotero SAR yamlengalenga yomwe imagwiritsidwa ntchito popanga mapu a mtunda imagwiritsa ntchito polarization yopingasa; kwa nthaka yomwe ili ndi roughness kuposa kutalika kwa mafunde, palibe kusintha koonekeratu mu HH kapena VV.

Mphamvu ya echo ya chinthu chomwecho pansi pa ma polarizations osiyanasiyana ndi yosiyana, ndipo kamvekedwe kazithunzi ndi kosiyana, zomwe zimawonjezera chidziwitso chozindikiritsa chandamale cha chinthu. Poyerekeza chidziwitso cha polarization yemweyo (HH, VV) ndi cross-polarization (HV, VH) akhoza kwambiri kuonjezera chidziwitso cha chithunzi cha radar, ndipo kusiyana kwa chidziwitso pakati pa polarization echoes ya zomera ndi zinthu zina zosiyana zimakhala zovuta kwambiri kusiyana ndi kusiyana pakati pa magulu osiyanasiyana.
Choncho, muzogwiritsira ntchito, njira yoyenera yopangira polarization ingasankhidwe malinga ndi zosowa zosiyanasiyana, ndipo kugwiritsa ntchito mozama kwa mitundu yambiri ya polarization kumathandizira kuwongolera kulondola kwa gulu la zinthu.