Problem reading an excel csp file using Matlab

Please help ! I wrote a matlab code to compute Position Velocity and Time in GPS but we have problem reading our data in the Excel CSP file ..

This is my code:

function eph = get_eph(ephemeridesfile) %GET_EPH The ephemerides contained in ephemeridesfile % are reshaped into a matrix with 21 rows and % as many columns as there are ephemerides.

% Typical call eph = get_eph('rinex_n.dat')

%Kai Borre 10-10-96 %Copyright (c) by Kai Borre %$Revision: 1.0 $ $Date: 1997/09/26 $

fide = fopen(ephemeridesfile); [eph, count] = fread(fide, Inf, 'double'); noeph = count/21; eph = reshape(eph, 21, noeph);

This is my error:

Error using fread Invalid file identifier. Use fopen to generate a valid file identifier.

Error in get_eph (line 13) [eph, count] = fread(fide, Inf, 'double');

Error in loadingscript (line 14) eph = get_eph(ephemeridesfile);

Answer 1

[Matt Tearle]

The error message is indicating a problem with opening the file. The file identifier returned by fopen does not refer to a valid, open file. That would generally indicated that the file doesn't exist or is corrupted. For example:

>> fid = fopen('nosuchfile.xyz')
fid = 
    -1

>> fread(fid)
Error using fread
Invalid file identifier.  Use fopen to generate a valid file identifier.