Ziziphi iindlela ezintathu ezahlukeneyo ze-polarization ze-SAR?

1. Yintoni i-SARukwahlukana?
I-Polarization: I-H polarization ethe tyaba; I-V polarization ethe tye, oko kukuthi, ulwalathiso lokungcangcazela lwentsimi ye-electromagnetic. Xa i-satellite ithumela isignali emhlabeni, ulwalathiso lokungcangcazela lwe-radio wave esetyenziswayo lunokuba ngeendlela ezininzi. Ezisetyenziswayo ngoku zezi:

I-Horizontal polarization (H-horizontal): I-Horizontal polarization ithetha ukuba xa i-satellite ithumela isignali emhlabeni, icala lokungcangcazela kwe-radio wave yayo lithe tyaba. I-Vertical polarization (V-vertical): I-vertical polarization ithetha ukuba xa i-satellite ithumela isignali emhlabeni, icala lokungcangcazela kwe-radio wave yayo lithe tyaba.

Ukuhanjiswa kwamaza e-electromagnetic kwahlulwe ngamaza angqindilili (H) kunye namaza angqindilili (V), kwaye ukwamkelwa kwahlulwe ngamaza angqindilili (H) kunye nawave angqindilili (V). Inkqubo yeradar esebenzisa i-H kunye ne-V linear polarization isebenzisa isibini seempawu ukumela i-transmission kunye ne-reception polarization, ukuze ibe nezi ndlela zilandelayo—HH, VV, HV, VH.

(1) HH - yokudlulisela ngokuthe tye kunye nokwamkela ngokuthe tye

(2) VV - yokudlulisela ngokuthe nkqo kunye nokwamkela ngokuthe nkqo

(3) I-HV - yokudlulisela ngokuthe tye kunye nokwamkela ngokuthe nkqo

(4) VH - yokudlulisela ngokuthe nkqo kunye nokwamkela ngokuthe tye

Ezimbini zokuqala kwezi ndibaniselwano ze-polarization zibizwa ngokuba zii-polarizations ezifanayo kuba ii-transmit kunye ne-receive polarizations ziyafana. Ezi zimbini zokugqibela zibizwa ngokuba zii-cross polarizations kuba ii-transmit kunye ne-receive polarizations zihambelana.

2. Yintoni i-single polarization, i-dual polarization, kunye ne-full polarization kwi-SAR?

I-single polarization ibhekisa kwi-(HH) okanye (VV), oku kuthetha (ukudluliselwa okuthe tye kunye nokwamkelwa okuthe tye) okanye (ukudluliselwa okuthe tye kunye nokwamkelwa okuthe tye) (ukuba ufunda icandelo le-radar yemozulu, ngokubanzi yi-(HH).)

I-Dual polarization ibhekisa ekongezeni enye imo ye-polarization kwimo enye ye-polarization, efana ne-(HH) transmission ethe tyaba kunye ne-horizontal reception + (HV) transmission ethe tyaba kunye ne-vertical reception.

Itekhnoloji epheleleyo ye-polarization yeyona inzima, ifuna ukuhanjiswa kwe-H kunye ne-V ngaxeshanye, oko kukuthi, iindlela ezine ze-polarization ze-(HH) (HV) (VV) (VH) zikhona ngaxeshanye.

Iinkqubo zeradar zinokuba namanqanaba ahlukeneyo obunzima be-polarization:

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

(2)Ukwahlulwahlulwa kabini: HH+HV; VV+VH; HH+VV

(3) Ii-polarizations ezine: HH+VV+HV+VH

Iiradar ze-Orthogonal polarization (oko kukuthi i-full polarization) zisebenzisa ezi polarization zine kwaye zilinganisa umahluko wesigaba phakathi kweetshaneli kunye ne-amplitude. Ezinye iiradar ze-dual-polarization zikwalinganisa umahluko wesigaba phakathi kweetshaneli, njengoko esi sigaba sidlala indima ebalulekileyo ekutsaleni ulwazi lwe-polarization.

Imifanekiso yesathelayithi yeradar Ngokuphathelele i-polarization, izinto ezahlukeneyo ezibonwayo zisasaza amaza ahlukeneyo e-polarization kumaza ahlukeneyo e-polarization. Ke ngoko, i-space remote sensing ingasebenzisa iibhendi ezininzi ukwandisa umxholo wolwazi, okanye isebenzise i-polarizations ezahlukeneyo ukuphucula nokuphucula ukuchaneka kokuchongwa kwethagethi.

3. Ungayikhetha njani indlela yokupholanisa isathelayithi yeradar ye-SAR?

Amava abonisa ukuba:

Kwizicelo zaselwandle, i-HH polarization ye-L band ibuthathaka ngakumbi, ngelixa i-VV polarization ye-C band ingcono;

Kwingca neendlela ezisasazeke kancinci, i-horizontal polarization yenza izinto zibe nomahluko omkhulu, ngoko ke i-spaceborne SAR esetyenziselwa imephu yomhlaba isebenzisa i-horizontal polarization; kumhlaba onoburhabaxa obungaphezulu kobude be-wavelength, akukho tshintsho lucacileyo kwi-HH okanye kwi-VV.

Amandla e-echo yento enye phantsi kwe-polarizations ezahlukeneyo ahlukile, kwaye ithoni yomfanekiso nayo yahlukile, nto leyo eyandisa ulwazi lokuchonga injongo yento. Ukuthelekisa ulwazi lwe-polarization efanayo (HH, VV) kunye ne-cross-polarization (HV, VH) kunokunyusa kakhulu ulwazi lomfanekiso we-radar, kwaye umahluko wolwazi phakathi kwe-polarization echoes yezityalo kunye nezinye izinto ezahlukeneyo ubuthathaka ngakumbi kunomahluko phakathi kwamaqela ahlukeneyo.
Ke ngoko, kwizicelo ezisebenzayo, imo efanelekileyo yokuphola inokukhethwa ngokweemfuno ezahlukeneyo, kwaye ukusetyenziswa ngokubanzi kweendlela ezininzi zokuphola kunceda ekuphuculeni ukuchaneka kokuhlelwa kwezinto.