47 lines
1.8 KiB
Mathematica
47 lines
1.8 KiB
Mathematica
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function word = checkPhase(word, D30Star)
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%Checks the parity of the supplied 30bit word.
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%The last parity bit of the previous word is used for the calculation.
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%A note on the procedure is supplied by the GPS standard positioning
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%service signal specification.
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%
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%word = checkPhase(word, D30Star)
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%
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% Inputs:
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% word - an array with 30 bit long word from the navigation
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% message (a character array, must contain only '0' or
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% '1').
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% D30Star - the last bit of the previous word (char type).
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%
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% Outputs:
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% word - word with corrected polarity of the data bits
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% (character array).
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%--------------------------------------------------------------------------
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% SoftGNSS v3.0
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%
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% Written by Darius Plausinaitis and Dennis M. Akos
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%--------------------------------------------------------------------------
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%This program is free software; you can redistribute it and/or
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%modify it under the terms of the GNU General Public License
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%as published by the Free Software Foundation; either version 2
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%of the License, or (at your option) any later version.
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%
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%This program is distributed in the hope that it will be useful,
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%but WITHOUT ANY WARRANTY; without even the implied warranty of
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%MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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%GNU General Public License for more details.
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%
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%You should have received a copy of the GNU General Public License
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%along with this program; if not, write to the Free Software
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%Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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%USA.
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%--------------------------------------------------------------------------
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% CVS record:
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% $Id: checkPhase.m,v 1.1.2.4 2006/08/14 11:38:22 dpl Exp $
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if D30Star == '1'
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% Data bits must be inverted
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word(1:24) = invert(word(1:24));
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end
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