www.gusucode.com > GPS_SDR_GPS软件接收机源码 > code4/GNSS_SDR/include/checkPhase.m
function word = checkPhase(word, D30Star) %Checks the parity of the supplied 30bit word. %The last parity bit of the previous word is used for the calculation. %A note on the procedure is supplied by the GPS standard positioning %service signal specification. % %word = checkPhase(word, D30Star) % % Inputs: % word - an array with 30 bit long word from the navigation % message (a character array, must contain only '0' or % '1'). % D30Star - the last bit of the previous word (char type). % % Outputs: % word - word with corrected polarity of the data bits % (character array). %-------------------------------------------------------------------------- % SoftGNSS v3.0 % % Written by Darius Plausinaitis and Dennis M. Akos %-------------------------------------------------------------------------- %This program is free software; you can redistribute it and/or %modify it under the terms of the GNU General Public License %as published by the Free Software Foundation; either version 2 %of the License, or (at your option) any later version. % %This program is distributed in the hope that it will be useful, %but WITHOUT ANY WARRANTY; without even the implied warranty of %MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the %GNU General Public License for more details. % %You should have received a copy of the GNU General Public License %along with this program; if not, write to the Free Software %Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, %USA. %-------------------------------------------------------------------------- % CVS record: % $Id: checkPhase.m,v 1.1.2.4 2006/08/14 11:38:22 dpl Exp $ if D30Star == '1' % Data bits must be inverted word(1:24) = invert(word(1:24)); end