74 lines
3.3 KiB
Mathematica
74 lines
3.3 KiB
Mathematica
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function [channel] = preRun(acqResults, settings)
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%Function initializes tracking channels from acquisition data. The acquired
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%signals are sorted according to the signal strength. This function can be
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%modified to use other satellite selection algorithms or to introduce
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%acquired signal properties offsets for testing purposes.
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%
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%[channel] = preRun(acqResults, settings)
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%
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% Inputs:
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% acqResults - results from acquisition.
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% settings - receiver settings
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%
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% Outputs:
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% channel - structure contains information for each channel (like
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% properties of the tracked signal, channel status etc.).
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%--------------------------------------------------------------------------
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% SoftGNSS v3.0
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%
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% Copyright (C) Darius Plausinaitis
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% Written by Darius Plausinaitis
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% Based on Peter Rinder and Nicolaj Bertelsen
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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: preRun.m,v 1.8.2.20 2006/08/14 11:38:22 dpl Exp $
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%% Initialize all channels ================================================
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channel = []; % Clear, create the structure
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channel.PRN = 0; % PRN number of the tracked satellite
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channel.acquiredFreq = 0; % Used as the center frequency of the NCO
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channel.codePhase = 0; % Position of the C/A start
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channel.status = '-'; % Mode/status of the tracking channel
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% "-" - "off" - no signal to track
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% "T" - Tracking state
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%--- Copy initial data to all channels ------------------------------------
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channel = repmat(channel, 1, settings.numberOfChannels);
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%% Copy acquisition results ===============================================
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%--- Sort peaks to find strongest signals, keep the peak index information
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[junk, PRNindexes] = sort(acqResults.peakMetric, 2, 'descend');
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%--- Load information about each satellite --------------------------------
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% Maximum number of initialized channels is number of detected signals, but
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% not more as the number of channels specified in the settings.
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%for ii = 1:min([settings.numberOfChannels, sum(acqResults.carrFreq > 0)])
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for ii = 1:settings.numberOfChannels
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channel(ii).PRN = PRNindexes(ii);
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channel(ii).acquiredFreq = acqResults.carrFreq(PRNindexes(ii));
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channel(ii).codePhase = acqResults.codePhase(PRNindexes(ii));
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% Set tracking into mode (there can be more modes if needed e.g. pull-in)
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channel(ii).status = 'T';
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end
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