Yiziphi izindlela ezintathu ezahlukene ze-polarization ze-SAR?

1. Kuyini i-SARukwahlukana?
I-Polarization: I-polarization evundlile engu-H; i-polarization evundlile engu-V, okungukuthi, isiqondiso sokudlidliza sensimu ye-electromagnetic. Lapho isathelayithi idlulisela isignali phansi, isiqondiso sokudlidliza segagasi lomsakazo elisetshenziswayo singaba ngezindlela eziningi. Ezisetshenziswayo njengamanje yilezi:

I-polarization Evundlile (H-horizontal): I-polarization Evundlile isho ukuthi lapho isathelayithi idlulisela isignali phansi, isiqondiso sokudlidliza segagasi layo lomsakazo siyavundlile. I-polarization Evundlile (V-vertical): I-polarization Evundlile isho ukuthi lapho isathelayithi idlulisela isignali phansi, isiqondiso sokudlidliza segagasi layo lomsakazo siyavundlile.

Ukudluliswa kwamagagasi kagesi kuhlukaniswe ngamagagasi avundlile (H) kanye namagagasi aqondile (V), kanti ukwamukelwa kuhlukaniswe ngamagagasi H kanye no-V. Uhlelo lwe-radar olusebenzisa i-H kanye ne-V linear polarization lusebenzisa ama-symbols amabili ukumela i-transmission kanye ne-reception polarization, ukuze lube neziteshi ezilandelayo—HH, VV, HV, VH.

(1) HH - yokudlulisela okuvundlile kanye nokwamukela okuvundlile

(2) i-VV - yokudlulisela okuqondile kanye nokwamukela okuqondile

(3) I-HV - yokudlulisela okuvundlile kanye nokwamukela okuqondile

(4) VH - yokudlulisela okuqondile kanye nokwamukela okuvundlile

Izinhlanganisela ezimbili zokuqala zalezi zinhlobo ze-polarization zibizwa ngokuthi i-polarizations efanayo ngoba i-transmit kanye ne-receive polarizations ziyafana. Izinhlanganisela ezimbili zokugcina zibizwa ngokuthi i-cross polarizations ngoba i-transmit kanye ne-receive polarizations zihambisana kahle.

2. Kuyini ukuphola okukodwa, ukuphola okubili, kanye nokuphola okugcwele ku-SAR?

I-polarization eyodwa ibhekisela ku-(HH) noma (VV), okusho ukuthi (ukudluliselwa okuvundlile kanye nokwamukelwa okuvundlile) noma (ukudluliselwa okuvundlile kanye nokwamukelwa okuvundlile) (uma ufunda insimu ye-radar yesimo sezulu, ngokuvamile yi-(HH).)

Ukuhlukaniswa okubili kubhekisela ekungezeni enye imodi yokuhlukaniswa kwe-polarization kwimodi eyodwa yokuhlukaniswa kwe-polarization, njengokudluliselwa okuvundlile (HH) kanye nokwamukelwa okuvundlile + (HV) kanye nokwamukelwa okuvundlile.

Ubuchwepheshe obuphelele bokuhlukaniswa kwamandla buyiyona enzima kakhulu, obudinga ukudluliswa kwe-H kanye ne-V ngesikhathi esisodwa, okungukuthi, izindlela ezine zokuhlukanisa amandla ze-(HH) (HV) (VV) (VH) zikhona ngesikhathi esisodwa.

Izinhlelo ze-radar zingaba namazinga ahlukene obunzima be-polarization:

(1) Ukwehlukaniswa okukodwa: HH; VV; HV; VH

(2)Ukwehlukaniswa okubili: HH+HV; VV+VH; HH+VV

(3) Ukwahlukana okune: HH+VV+HV+VH

Ama-radar e-Orthogonal polarization (okungukuthi i-polarization egcwele) asebenzisa lawa ma-polarization amane futhi alinganisa umehluko wesigaba phakathi kweziteshi kanye ne-amplitude. Amanye ama-radar e-dual-polarization nawo alinganisa umehluko wesigaba phakathi kweziteshi, njengoba lesi sigaba sidlala indima ebalulekile ekukhishweni kolwazi lwe-polarization.

Izithombe zesathelayithi ze-radar Ngokuphathelene ne-polarization, izinto ezahlukene ezibonwayo zihlakaza amagagasi ahlukene e-polarization kumagagasi ahlukene e-polarization ezigamekweni. Ngakho-ke, ukuzwa okukude kwesikhala kungasebenzisa amabhendi amaningi ukwandisa okuqukethwe kolwazi, noma kusebenzise i-polarizations ehlukene ukuthuthukisa nokuthuthukisa ukunemba kokuhlonza okuqondiwe.

3. Ungayikhetha kanjani imodi yokuhlukanisa yesathelayithi yeradar ye-SAR?

Okuhlangenwe nakho kubonisa ukuthi:

Ngezinhlelo zokusebenza zasolwandle, i-HH polarization yebhendi le-L ibucayi kakhulu, kuyilapho i-VV polarization yebhendi le-C ingcono;

Ngotshani nemigwaqo esakazeke kancane, i-polarization evundlile yenza izinto zibe nomehluko omkhulu, ngakho-ke i-SAR esemkhathini esetshenziselwa ukumaka indawo isebenzisa i-polarization evundlile; ezweni elinobukhulu obukhulu kunobude be-wavelength, akukho shintsho olusobala ku-HH noma ku-VV.

Amandla e-echo ento efanayo ngaphansi kwe-polarizations ehlukene ahlukile, futhi ithoni yesithombe nayo ihlukile, okwandisa ulwazi lokuhlonza into ekuhlosiwe kuyo. Ukuqhathanisa ulwazi lwe-polarization efanayo (HH, VV) kanye ne-cross-polarization (HV, VH) kungakhulisa kakhulu ulwazi lwesithombe se-radar, futhi umehluko wolwazi phakathi kwe-polarization echoes yezitshalo nezinye izinto ezahlukene uzwela kakhulu kunomehluko phakathi kwama-band ahlukene.
Ngakho-ke, ekusetshenzisweni okungokoqobo, imodi efanele yokuhlukanisa ingakhethwa ngokuya ngezidingo ezahlukene, futhi ukusetshenziswa okubanzi kwezindlela eziningi zokuhlukanisa kusiza ekuthuthukiseni ukunemba kokuhlukaniswa kwezinto.