An alternative for rovio could be VINS

[greymfm]

If you are looking for an rovio-alternative, you probably already know VINS :-)
https://github.com/HKUST-Aerial-Robotics/VINS-Mobile (ported to iphone)
https://www.youtube.com/watch?v=CI01qbPWlYY

Do you think to get fisheye camera and IMU frames at high rates (20 Hz and 100 Hz) from the Tango device for this? :-)

[ijinjay]

Actually I am building a VINS of myself :-)
For the work of HKUST-Aerial-Robotics, I have tried their app. The initialization is really slow on my iPad Pro. Anyway the idea of IMU pre-integration is really good.