Hi guys!

Here is the latest revision of my favorite hobby project based on Multiwii project. In two words: it's pretty stable, improved and extended version of Multiwii.

Changes:

• INS (inertial navigation system) integrated with GPS and Baro

• predefined PIDs to fly out of the box for frames 330 and bigger

• completely different precise althold integrated with INS

• right altitude management by setting desired vario (vertical speed) with throttle stick

• single PID controller for hovering and altitude management

• stable hovering trottle estimator/corrector by I-part of alt PID controller

• smart land detector

• reduced effect of air-cushion to avoid incorrect raw baro values and jumps near the ground accordingly (integrated with INS)

• controllable by desired vario (vertical speed) landing

• new SAFE_ALT_DURING_AH define. It helps to protect descending less than specified in define altitude. Activated when SAFE_ALT box activated in GUI.

• precise, rapid, sensitive to external perturbations (wind, pushes) GPS-INS position hold (INS_PH_NAV_ON define)

• possibility to fly with activated position hold and stop at predicted point on stick release (tunable by Pos-I value at GUI)

• wait for target altitude at RTH and WP navigation

• skip whole RTH cycle if distance less than RTH_RADIUS meters and make a landing

• safe and soft takeoff on RTH and WP Navigation

• for safety prevent arm if RTH or NAV switched on

• new auto config defines for UBLOX and MTK3339 modules

• precised gyro calibration + 3 axis acel calibration + filtered mag calibration to avoid min/max noise values

• frsky telemetry adopted for er9x-frsky TX firmware

• 50hz PID output for althold, gps modes

• cycle time independent final PID controller

• optimized math

• a lot of fixes

For more details please read release_note.txt, see config.h and also here http://forum.rcdesign.ru/blogs/83206/blog22332.html

Tips and tricks:

• for INS it's better to use u-blox modules with revision from 6 to 8 (although 7th was not tested). With MTK modules position hold is less precise but in general it's ok also, where PID parameters has to be ~20% less for its.
• for INS it's good to have calibrated accel in 3 axises with +/-512 for each axis with error +/-(1-3)
• for configuration the best tool is https://play.google.com/store/apps/details?id=com.ezio.multiwii
• for this release arduino 1.6.7 was used https://www.arduino.cc/en/Main/OldSoftwareReleases
• before 1st upload clean eeprom http://forum.rcdesign.ru/f123/thread283798-74.html#post4263236

This firmware was optimized for AIOP (ALL IN ONE PRO Flight Controller), or other with Atmega1280/2560 + mpu6050 + ms5611 + hmc5883 (but take care about pinout). But you can try to play with other sensors also.

Videos from my friend's youtube channel: https://www.youtube.com/user/artnesterof/videos

Blogs:

• https://www.rcgroups.com/forums/showthread.php?t=2787668
• http://www.multiwii.com/forum/viewtopic.php?f=8&t=7877
• http://forum.rcdesign.ru/blogs/83206/

Enjoy! ;)