function?data?=?bpBasic（data）;
????%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
????%this?function?performs?a?basic?backprojection?operationthe?following
????%fields?need?to?be?populated
????
????%data.Nfft:?size?of?the?FFT?to?form?the?range?profile
????%data.deltaF:?step?size?of?frequency?data（Hz）
????%data.minF:?vector?containing?the?start?frequeny?of?each?pulse（Hz）
????%data.x_mat:?the?x-position?of?each?pixel（m）
????%data.y_mat:?the?y-position?of?each?pixel（m）
????%data.z_mat:?the?z-position?of?each?pixel（m）
????%data.AntX:?the?x-position?of?the?sensor?at?each?pulse（m）
????%data.AntY:?the?y-position?of?the?sensor?at?each?pulse（m）
????%data.AntZ:?the?z-position?of?the?sensor?at?each?pulse（m）
????%data.RO:?the?range?to?scene?center（m）
????%data.phdata:?phase?histroy?data（frequency?domain）?fast?time?in
????%rowsslow?time?in?columns
????
????%the?output?is:
????%data.im_final:?the?complex?image?value?at?each?pixel
????
????%written?by?leroy?gorhamair?force?rewardh?laboratory?WAPAFBOH
????%email:leroy.gorham@wpafb.af.mil
????%data?rrelwased:?8?Apr?2010
????%gorhamL.A.?and?Moore?J.J.?SRimage?formation?boolbox?for
????%matab“algrorithm?for?synthetic?aperture?radar?imagery?XVII?7669SPIE
????%（2010）
????%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
????%%
????
????%define?speed?of?the?light
????c?=?299792458;
????
????%determine?the?size?of?the?phase?histroy?data
????data.K?=?size（data.phdata1）;%the?number?of?frequency?bins?per?pulse
????data.Np?=?size（data.phdata2）;%the?number?of?pulses
????
????%determine?the?zaimuth?angles?of?the?image?pulses（radians）
????data.AntAz?=?unwrap（atan2（data.AntYdata.AntX））;
????
????%determine?the?average?azimuth?angle?step?size（radians）
????data.deltaAz?=?abs（mean（diff（data.AntAz）））;
????
????%determine?the?total?azimuth?angel?of?the?aperture（radians）
????data.totalAz?=?max（data.AntAz）?-?min（data.AntAz）;
????
????%determine?the?maximm?scene?size?of?the?image（m）
????data.maxWr?=?c/（2