Usage of SP3 ephemeris and satellite clocks

[ege010]

In order to use ephemeris and satellite clocks in SP3 format (e.g. to exploit IGS precise products) the following needs to be implemented:

1. interpolation of SP3 satellite positions (typically by Lagrange polynomials): http://sourceforge.net/p/gogps/code/HEAD/tree/trunk/utility/gps/interpolate_SP3_coord.m
2. interpolation of SP3 satellite clocks (typically a linear interpolation is enough): http://sourceforge.net/p/gogps/code/HEAD/tree/trunk/utility/gps/interpolate_SP3_clock.m
3. computation of the Sun position in ECEF coordinates (in order to do this, an already existing Java implementation of JPL ephemeris would be very welcome!): http://sourceforge.net/p/gogps/code/HEAD/tree/trunk/utility/sun_moon/sun_moon_pos.m
4. reading of (at least) satellite antenna phase center offsets from PCO/PCV files (ATX format): http://sourceforge.net/p/gogps/code/HEAD/tree/trunk/input_output/ATX/read_antenna_PCV.m
5. application of satellite antenna phase center offsets, by computing the rotation of each satellite towards the Sun: http://sourceforge.net/p/gogps/code/HEAD/tree/trunk/utility/gps/interpolate_SP3_coord.m#l91
6. reading of differential code biases (DCBs): http://sourceforge.net/p/gogps/code/HEAD/tree/trunk/input_output/DCB/load_dcb.m
7. application of DCBs: http://sourceforge.net/p/gogps/code/HEAD/tree/trunk/positioning/satellite_positions.m#l96
8. the complete procedure then will be as follows: http://sourceforge.net/p/gogps/code/HEAD/tree/trunk/positioning/satellite_positions.m#l86