Loading...
 
ESA > Join & Share > Forums > CryoSat Forum - Ocean and Coastal Zones > how to use angle information in "beam_parameter" to construct echo model and retrack echo

CryoSat Forum - Ocean and Coastal Zones

Help

Show posts:
Jump to forum:

how to use angle information in "beam_parameter" to construct echo model and retrack echo

I want to process Cryosat2 Roll Compaign data distributed by ESA. First, I should to retrack echo data in L1b data of SARIn mode. When I try to retrack the sea echo, I have to use win_delay, Ho, and look angle to construct mean echo model for every beam, and then sum them into one multilooked echo. Filed 92# in SARIn data include the beam angle information, and give the look_angle_start, look_angle_stop and look number( N1 : before stack weighting; and N2 after stack weighting ) to be used in echo model. But I'm still confused by two parameter N1 and N2, with only one pair of look_angle_start/stop. If the data products have been weighted(as Doc have been anounced), then should N1 be used, and the angle width for each beam should be equal to (look_angle_stop - look_angle_start)/N1, and also equal to Lambda / ( 2 * Vs ) * PRF / 64. But they are not same. So there must some wrong idea in my understanding of how to use beam_parameter. I have read hand book, L1b data products specfication, and "Beam behavior parameters in Cryosat Level1b products"(Doc: C2-TN_ARS_GS_5155). but still can't get any answer. Another question is, what is the relationship between "Stack center angle"( in beam_param) and boresight angle? Could you give me some advise? Thank you!

Show posts:
Jump to forum: