Thanks to Jordi (thank you for this possibility :) ) I started play with Ardupilot . The main goal is to connect it to remzibi OSD (poor man's OSD) -
in simplest way to Ardupilot , all advantages of both devices must be keeped autopiloting and custom layout config of OSD .
Ardupilot is device designed for autopiloting and was not made for any FPV flight - so GPS originally is very close to autopilot board and VidTX probably also (VidTX is jaming GPS) , but using Video and GPS should be mounted at distance to each other .
Ardu by his self are greate source of noise also - so any separation ( LC and RC lopass filter) must be considered for coupling RC RX signals .
There is not possible (I do not know why probably IDE reads USB device VID or PID) to made and Ardupilot software update by USB OTi cable (belongs to OSD) - but original USB works OK (however can better) .
I already concider to compile bootloader for mega328 as Megaload - will take from memory only 1k , as original ardu bootloader takes 2k now , also any USB-uart or rs232-uart cable will able to use for firmware update . In this case will be possible to use even mega168 Ardu with 2.2.3 software .
OTi cable works great as serial monitor for Ardupilot or as debuging or whatever .
Will test it more with PC GPS emulator .
It is possible to connect remzibi GPS - but must be done some config in software like serial.begin(9600) for older GPS module or serial.begin(38400) for last relase , so in fact is very easy . Hardware change is a one diode on bottom of adru board . The config file changes are very simple .
In total - Ardupilot is very nice and flexible device even using Adru IDE for programing - for beginers is even much more easier to use then raw GCC .
Ardupilot team made really good job till now - in fact that sources are open - so this solution is real future having autopilot solution .
For now ardu 2.2.3 firmaware takes only 14,4k (NMEA GPS) so not even 50% of total memory (32k at mega328) .
Next soon .