Zeziphi iindlela ezintathu ezahlukeneyo ze-polarization ze-SAR?

1. Yintoni iSARi-polarization?
I-polarization: H i-polarization ethe tye; I-polarization ye-V ethe nkqo, oko kukuthi, isalathiso sokungcangcazela kwindawo ye-electromagnetic. Xa isathelayithi ithumela umqondiso emhlabeni, indlela eshukuma ngayo igagasi likanomathotholo elisetyenziswayo linokuba ngeendlela ezininzi. Ezona zisetyenziswayo ngoku zezi:

I-polarization ethe tyaba (H-horizontal): I-polarization ethe tyaba ithetha ukuba xa isathelayithi ithumela umqondiso emhlabeni, icala lokungcangcazela kwamaza erediyo lithe tye. I-polarization ethe nkqo (i-V-nkqo): I-polarization ethe nkqo ithetha ukuba xa isathelayithi ithumela umqondiso emhlabeni, icala le-vibration ye-radio wave lithe nkqo.

I-electromagnetic wave transmission ihlukaniswe ngamaza anqamlekileyo (H) kunye namaza anqamlekileyo (V), kwaye ulwamkelo lukwahlulahlulwe kwi-H kunye ne-V. Inkqubo ye-radar esebenzisa i-H kunye ne-V ye-polarization yomgca isebenzisa isibini seesimboli ukumela ukuhanjiswa kunye nokwamkela i-polarization, ngoko inokuba nala majelo alandelayo—HH, VV, HV, VH.

(1) I-HH - yokuhanjiswa okuthe tye kunye nokwamkelwa okuthe tye

(2) I-VV - yokudluliselwa ngokuthe nkqo kunye nokwamkelwa ngokuthe nkqo

(3) I-HV - yokuhanjiswa okuthe tye kunye nokwamkelwa ngokuthe nkqo

(4) I-VH - yokudluliselwa ngokuthe nkqo kunye nokwamkelwa okuthe tye

Ezokuqala ezimbini zezi ndibaniselwano zepolarization zibizwa ngokuba yi-polarizations efanayo ngenxa yokuba ukuhanjiswa kunye nokufumana iipolarizations ziyafana. Iindibaniso ezimbini zokugqibela zibizwa ngokuba yi-cross polarizations kuba ukuhanjiswa kunye nokufumana iipolarizations zi-orthogonal enye kwenye.

2. Yintoni i-polarization enye, i-polarization kabini, kunye ne-polarization epheleleyo kwi-SAR?

I-polarization enye ibhekisa ku-(HH) okanye (VV), okuthetha (ugqithiso oluthe tyaba kunye nolwamkelo oluthe tye) okanye (ugqithiso oluthe nkqo kunye nolwamkelo oluthe nkqo) (ukuba ufunda icandelo le-meteorological radar, ngokuqhelekileyo (HH).

I-polarization kabini ibhekiselele ekongezeni enye imo yepolarization kwimowudi enye yepolarization, efana (HH) ukuhanjiswa okuthe tyaba kunye nolwamkelo oluthe tye + (HV) oluthe tyaba kunye nolwamkelo oluthe nkqo.

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

Iinkqubo zeRadar zinokuba namanqanaba ahlukeneyo obunzima bepolarization:

(1) I-polarization enye: HH; VV; HV; VH

(2)I-polarization kabini: HH+HV; VV+VH; HH+VV

(3) Iipolarizations ezine: HH+VV+HV+VH

I-Orthogonal polarization (oko kukuthi i-polarization epheleleyo) iirada zisebenzisa ezi polarizations zine kwaye zilinganisa umahluko wesigaba phakathi kwamajelo kunye ne-amplitude. Ezinye iirada ze-dual-polarization nazo zilinganisa umehluko wesigaba phakathi kwamajelo, njengoko esi sigaba sidlala indima ebalulekileyo ekutsalweni kolwazi lwepolarization.

Imifanekiso yesathelayithi yeRadar Ngokwepolarization, izinto ezahlukeneyo ezijongiweyo zisasaza umva amaza ahlukeneyo epolarization kwizehlo ezahlukeneyo zamaza epolarization. Ke ngoko, imvakalelo ekude yendawo inokusebenzisa iibhendi ezininzi ukunyusa umxholo wolwazi, okanye isebenzise i-polarizations eyahlukeneyo ukuphucula nokuphucula ukuchaneka kokuchongwa okujoliswe kuko.

3. Indlela yokukhetha imo yepolarization yesathelayithi ye-radar ye-SAR?

Amava abonisa ukuba:

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

Kwingca ephantsi kunye neendlela, i-polarization ethe tyaba yenza ukuba izinto zibe nentlukwano enkulu, ngoko ke i-SAR ye-spaceborne esetyenziselwa i-terrain mapping isebenzisa i-polarization ethe tye; kumhlaba onoburhabaxa obukhulu kunobude bobude, akukho tshintsho lucacileyo kwi-HH okanye kwi-VV.

Amandla e-echo yento efanayo phantsi kwe-polarizations eyahlukileyo iyahluka, kwaye ithoni yomfanekiso nayo ihluke, eyandisa ulwazi lokuchonga into ekujoliswe kuyo. Ukuthelekisa ulwazi lwe-polarization efanayo (HH, VV) kunye ne-cross-polarization (HV, VH) inokunyusa kakhulu ulwazi lomfanekiso we-radar, kwaye umahluko wolwazi phakathi kwe-polarization echoes yezityalo kunye nezinye izinto ezahlukeneyo zinovakalelo ngakumbi kunomahluko phakathi bands ezahlukeneyo.
Ngoko ke, kwizicelo ezisebenzayo, imodi ye-polarization efanelekileyo ingakhethwa ngokweemfuno ezahlukeneyo, kwaye ukusetyenziswa ngokubanzi kweendlela ezininzi ze-polarization kukulungele ukuphucula ukuchaneka kokuhlelwa kwezinto.