Remove build and data folders, move tests and utils to the base of the source tree

utils/matlab/libs/geoFunctions/topocent.m

@@ -0,0 +1,58 @@
+function [Az, El, D] = topocent(X, dx)
+% TOPOCENT  Transformation of vector dx into topocentric coordinate
+%          system with origin at X.
+%          Both parameters are 3 by 1 vectors.
+%
+% [Az, El, D] = topocent(X, dx);
+%
+%   Inputs:
+%       X           - vector origin coordinates (in ECEF system [X; Y; Z;])
+%       dx          - vector ([dX; dY; dZ;]).
+%
+%   Outputs:
+%       D           - vector length. Units like units of the input
+%       Az          - azimuth from north positive clockwise, degrees
+%       El          - elevation angle, degrees
+
+% GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
+% This file is part of GNSS-SDR.
+%
+% SPDX-FileCopyrightText: Kai Borre 11-24-96
+% SPDX-License-Identifier: GPL-3.0-or-later
+
+%==========================================================================
+
+dtr = pi/180;
+
+[phi, lambda, h] = togeod(6378137, 298.257223563, X(1), X(2), X(3));
+
+cl  = cos(lambda * dtr);
+sl  = sin(lambda * dtr);
+cb  = cos(phi * dtr);
+sb  = sin(phi * dtr);
+
+F   = [-sl -sb*cl cb*cl;
+    cl -sb*sl cb*sl;
+    0    cb   sb];
+
+local_vector = F' * dx;
+E   = local_vector(1);
+N   = local_vector(2);
+U   = local_vector(3);
+
+hor_dis = sqrt(E^2 + N^2);
+
+if hor_dis < 1.e-20
+    Az = 0;
+    El = 90;
+else
+    Az = atan2(E, N)/dtr;
+    El = atan2(U, hor_dis)/dtr;
+end
+
+if Az < 0
+    Az = Az + 360;
+end
+
+D   = sqrt(dx(1)^2 + dx(2)^2 + dx(3)^2);
+%%%%%%%%% end topocent.m %%%%%%%%%