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function xERot = FlightTimeCorrection(xE, dTflightSeconds) |
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%xERot = FlightTimeCorrection(xE, dtflight); |
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% Compute rotated satellite ECEF coordinates caused by Earth |
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% rotation during signal flight time |
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% |
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% Inputs: |
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% xE - satellite ECEF position at time of transmission |
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% dtflight - signal flight time (seconds) |
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% |
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% Outputs: |
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% XeRot - rotated satelite position vector (ECEF at trx) |
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% |
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% Reference: |
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% IS GPS 200, 20.3.3.4.3.3.2 Earth-Centered, Inertial (ECI) Coordinate System |
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%Author: Frank van Diggelen |
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%Open Source code for processing Android GNSS Measurements |
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%See also "A software receiver for GPS and Galileo", K. Borre at al. |
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%Rotation angle (radians): |
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theta = GpsConstants.WE * dTflightSeconds; |
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%Apply rotation from IS GPS 200-E, 20.3.3.4.3.3.2 |
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%Note: IS GPS 200-E shows the rotation from ecef to eci |
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% so our rotation R3, is in the opposite direction: |
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R3 = [ cos(theta) sin(theta) 0; |
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-sin(theta) cos(theta) 0; |
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0 0 1]; |
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xERot = (R3*xE(:))'; |
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end %end of function FlightTimeCorrection |
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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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