Kedu ụzọ atọ dị iche iche polarization nke SAR?

1. Gịnị bụ SARpolarization?
Polarization: H kehoraizin polarization; V vetikal polarization, ya bụ, vibration direction nke ala electromagnetic. Mgbe satịlaịtị na-ebufe mgbaama na ala, ntụzịaka ịma jijiji nke ebili mmiri redio ejiri mee ihe nwere ike ịdị n'ọtụtụ ụzọ. Ndị a na-eji ugbu a bụ:

Okirikiri polarization (H-horizontal): Ọkpụkpụ kwụ ọtọ pụtara na mgbe satịlaịtị na-ebufe mgbaama n'ala, ntụzịaka mmaji nke ebili mmiri redio ya bụ kehoraizin. Vertical polarization (V-vertical): Vertical polarization pụtara na mgbe satịlaịtị na-ebunye akara n'ala, ntụzịaka nke ụda redio ya bụ vetikal.

A na-ekewa nnyefe electromagnetic ka ọ bụrụ ebili mmiri kwụ ọtọ (H) na ebili mmiri kwụ ọtọ (V), a na-ekewakwa nnabata n'ime H na V. Usoro radar na-eji H na V linear polarization na-eji akara abụọ na-anọchi anya nnyefe na nnabata polarization. ya mere ọ nwere ike ịnwe ọwa ndị a-HH, VV, HV, VH.

(1) HH - maka nnyefe kehoraizin na nnabata kehoraizin

(2) VV - maka nnyefe kwụ ọtọ na nnabata vetikal

(3) HV - maka nnyefe kehoraizin na nnabata vetikal

(4) VH - maka nnyefe kwụ ọtọ na nnabata kwụ ọtọ

A na-akpọ nke abụọ mbụ n'ime ngwakọta polarization ndị a n'ihi na nnyefe na ịnata polarization bụ otu. A na-akpọ njikọ abụọ ikpeazụ nke cross polarizations n'ihi na nnyefe na ịnweta polarizations bụ orthogonal na ibe ha.

2. Gịnị bụ otu polarization, abụọ polarization, na zuru polarization na SAR?

Otu polarization na-ezo aka na (HH) ma ọ bụ (VV), nke pụtara (nfefe kwụ ọtọ na nnabata kwụ ọtọ) ma ọ bụ (nfefe vetikal na nnabata vetikal) (ọ bụrụ na ị na-amụ ubi nke radar meteorological, ọ bụ n'ozuzu (HH).)

Igwe okwu abụọ na-ezo aka ịgbakwụnye ụdị polarization ọzọ n'otu ọnọdụ polarization, dị ka (HH) nnyefe kwụ ọtọ na nnabata kwụ ọtọ + (HV) nnyefe kwụ ọtọ na nnabata kwụ ọtọ.

Teknụzụ polarization zuru oke bụ ihe kacha sie ike, na-achọ nnyefe nke H na V n'otu oge, ya bụ, ụdị polarization anọ nke (HH) (HV) (VV) (VH) dị n'otu oge.

Sistemu radar nwere ike inwe ọkwa dị iche iche nke mgbagwoju anya:

(1) Otu polarization: HH; VV; HV; VH

(2)Polarization abụọ: HH+HV; VV+VH; HH+VV

(3) Anọ polarizations: HH+VV+HV+VH

Orthogonal polarization (ya bụ zuru polarization) radars na-eji polarization anọ ndị a ma tụọ ọdịiche dị n'etiti ọwa yana njupụta. Ụfọdụ radar abụọ-polarization na-atụkwa ọdịiche nke usoro dị n'etiti ọwa, n'ihi na usoro a na-arụ ọrụ dị mkpa na nchịkọta ozi polarization.

Onyonyo satịlaịtị radar N'ihe gbasara polarization, ihe dị iche iche ahụrụ anya na-achụsasị ebili mmiri dị iche iche maka ebili mmiri polarization dị iche iche. Ya mere, nghọta ime oghere nwere ike iji ọtụtụ band iji welie ọdịnaya ozi, ma ọ bụ jiri polarization dị iche iche iji kwalite na melite izi ezi nke njirimara ebumnuche.

3. Olee otú ịhọrọ polarization mode nke SAR radar satịlaịtị?

Ahụmahụ na-egosi na:

Maka ngwa mmiri, HH polarization nke L band na-enwe mmetụta karịa, ebe VV polarization nke C band ka mma;

Maka ahịhịa na okporo ụzọ na-agbasasị ala, nhịahụ kwụ ọtọ na-eme ka ihe ndị ahụ nwee nnukwu ọdịiche, ya mere SAR mbara igwe ejiri maka eserese ala na-eji polarization kwụ ọtọ; n'ihi na ala na roughness karịrị ogologo wavelength, ọ dịghị mgbanwe doro anya na HH ma ọ bụ VV.

Ike nkwughachi nke otu ihe n'okpuru polarization dị iche iche dị iche iche, na ụda oyiyi ahụ dịkwa iche iche, nke na-eme ka ozi dịkwuo maka ịchọpụta ihe mgbaru ọsọ. Tụnyere ozi nke otu polarization (HH, VV) na cross-polarization (HV, VH) nwere ike ịbawanye ozi onyonyo radar nke ukwuu, na ọdịiche ozi dị n'etiti nkwughachi polarization nke ahịhịa na ihe ndị ọzọ dị iche iche na-enwe mmetụta karịa ọdịiche dị n'etiti. ìgwè dị iche iche.
Ya mere, na ngwa bara uru, enwere ike ịhọrọ ụdị polarization kwesịrị ekwesị dị ka mkpa dị iche iche si dị, na ojiji zuru oke nke ọtụtụ ụdị polarization na-eme ka mma nke nhazi ihe dị mma.