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function [gpsTime,fctSeconds] = Utc2Gps(utcTime) |
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% [gpsTime,fctSeconds] = Utc2Gps(utcTime) |
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% Convert the UTC date and time to GPS week & seconds |
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% |
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% Inputs: |
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% utcTime: [mx6] matrix |
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% utcTime(i,:) = [year,month,day,hours,minutes,seconds] |
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% year must be specified using four digits, e.g. 1994 |
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% year valid range: 1980 <= year <= 2099 |
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% |
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% Outputs: |
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% gpsTime: [mx2] matrix [gpsWeek, gpsSeconds], |
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% gpsWeek = number of weeks since GPS epoch |
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% gpsSeconds = number of seconds into gpsWeek, |
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% fctSeconds: full cycle time = seconds since GPS epoch (1980/01/06 00:00 UTC) |
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% Other functions needed: JulianDay.m, LeapSeconds.m |
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%initialize outputs |
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gpsTime=[]; |
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fctSeconds=[]; |
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[bOk]=CheckUtcTimeInputs(utcTime); |
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if ~bOk |
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return |
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end |
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HOURSEC = 3600; MINSEC = 60; |
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daysSinceEpoch = floor(JulianDay(utcTime) - GpsConstants.GPSEPOCHJD); |
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gpsWeek = fix(daysSinceEpoch/7); |
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dayofweek = rem(daysSinceEpoch,7); |
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% calculate the number of seconds since Sunday at midnight: |
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gpsSeconds = dayofweek*GpsConstants.DAYSEC + utcTime(:,4)*HOURSEC + ... |
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utcTime(:,5)*MINSEC + utcTime(:,6); |
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gpsWeek = gpsWeek + fix(gpsSeconds/GpsConstants.WEEKSEC); |
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gpsSeconds = rem(gpsSeconds,GpsConstants.WEEKSEC); |
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% now add leapseconds |
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leapSecs = LeapSeconds(utcTime); |
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fctSeconds = gpsWeek(:)*GpsConstants.WEEKSEC + gpsSeconds(:) + leapSecs(:); |
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% when a leap second happens, utc time stands still for one second, |
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% so gps seconds get further ahead, so we add leapsecs in going to gps time |
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gpsWeek = fix(fctSeconds/GpsConstants.WEEKSEC); |
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iZ = gpsWeek==0; |
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gpsSeconds(iZ) = fctSeconds(iZ); %set gpsSeconds directly, because rem(x,0)=NaN |
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gpsSeconds(~iZ) = rem(fctSeconds(~iZ),gpsWeek(~iZ)*GpsConstants.WEEKSEC); |
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gpsTime=[gpsWeek,gpsSeconds]; |
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assert(all(fctSeconds==gpsWeek*GpsConstants.WEEKSEC+gpsSeconds),... |
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'Error in computing gpsWeek, gpsSeconds'); |
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end %end of function Utc2Gps |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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function [bOk] = CheckUtcTimeInputs(utcTime) |
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%utility function for Utc2Gps |
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%check inputs |
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if size(utcTime,2)~=6 |
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error('utcTime must have 6 columns') |
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end |
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%check that year, month & day are integers |
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x = utcTime(:,1:3); |
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if any(any( (x-fix(x)) ~= 0 )) |
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error('year,month & day must be integers') |
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end |
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%check that year is in valid range |
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if ( any(utcTime(:,1)<1980) || any(utcTime(:,1)>2099) ) |
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error('year must have values in the range: [1980:2099]') |
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end |
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%check validity of month, day and time |
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if (any(utcTime(:,2))<1 || any(utcTime(:,2))>12 ) |
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error('The month in utcTime must be a number in the set [1:12]') |
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end |
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if (any(utcTime(:,3)<1) || any(utcTime(:,3)>31)) |
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error('The day in utcTime must be a number in the set [1:31]') |
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end |
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if (any(utcTime(:,4)<0) || any(utcTime(:,4)>=24)) |
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error('The hour in utcTime must be in the range [0,24)') |
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end |
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if (any(utcTime(:,5)<0) || any(utcTime(:,5)>=60)) |
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error('The minutes in utcTime must be in the range [0,60)') |
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end |
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if (any(utcTime(:,6)<0) || any(utcTime(:,6)>60)) |
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%Note: seconds can equal 60 exactly, on the second a leap second is added |
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error('The seconds in utcTime must be in the range [0,60]') |
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end |
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bOk = true; |
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end %end of function CheckUtcTimeInputs |
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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% Copyright 2016 Google Inc. |
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% |
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% Licensed under the Apache License, Version 2.0 (the "License"); |
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% you may not use this file except in compliance with the License. |
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% You may obtain a copy of the License at |
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% |
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% http://www.apache.org/licenses/LICENSE-2.0 |
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% |
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% Unless required by applicable law or agreed to in writing, software |
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% distributed under the License is distributed on an "AS IS" BASIS, |
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% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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% See the License for the specific language governing permissions and |
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% limitations under the License.
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