Thank you for your reply jmack.
I don't really understand how GPS_RAW works. Do I need to send the command GPS_RAW_INT and then wait for answer? I would read the variables fix_type, lat,lon and alt. No problem. But For me it doesn't make any sense to send GPS_RAW_INT with the following parameters:
mavlink_msg_gps_raw_int_pack(uint8_t system_id, uint8_t component_id, mavlink_message_t* msg, uint64_t time_usec, uint8_t fix_type, int32_t lat, int32_t lon, int32_t alt, uint16_t eph, uint16_t epv, uint16_t vel, uint16_t cog, uint8_t satellites_visible)
Lat, lon, alt -> I don't know them, I'm asking for them.
fix_type -> the same, I don't know, I'm asking for it.
And the same for the others, I find that all the parameters of the function are what I would like to know...I'm sorry if this is such a trivial question..
Apart from that, Is it possible to plan missions in the flight time? Once I'm flying?