{"action":"closed","issue":{"url":"https://api.github.com/repos/diydrones/ardupilot/issues/1494","labels_url":"https://api.github.com/repos/diydrones/ardupilot/issues/1494/labels{/name}","comments_url":"https://api.github.com/repos/diydrones/ardupilot/issues/1494/comments","events_url":"https://api.github.com/repos/diydrones/ardupilot/issues/1494/events","html_url":"https://github.com/diydrones/ardupilot/issues/1494","id":46023851,"number":1494,"title":"Copter: jump in altitude when EKF becomes available","user":{"login":"jschall","id":1015761,"avatar_url":"https://avatars.githubusercontent.com/u/1015761?v=3","gravatar_id":"","url":"https://api.github.com/users/jschall","html_url":"https://github.com/jschall","followers_url":"https://api.github.com/users/jschall/followers","following_url":"https://api.github.com/users/jschall/following{/other_user}","gists_url":"https://api.github.com/users/jschall/gists{/gist_id}","starred_url":"https://api.github.com/users/jschall/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/jschall/subscriptions","organizations_url":"https://api.github.com/users/jschall/orgs","repos_url":"https://api.github.com/users/jschall/repos","events_url":"https://api.github.com/users/jschall/events{/privacy}","received_events_url":"https://api.github.com/users/jschall/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/diydrones/ardupilot/labels/ArduCopter","name":"ArduCopter","color":"02e10c"},{"url":"https://api.github.com/repos/diydrones/ardupilot/labels/Safety%20Feature","name":"Safety Feature","color":"0052cc"}],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":8,"created_at":"2014-10-16T19:15:02Z","updated_at":"2015-04-13T01:35:12Z","closed_at":"2015-04-13T01:35:12Z","body":"If you get up in alt-hold before EKF becomes available, and subsequently EKF becomes available, the copter will very suddenly either fall a bit or climb a bit. This is very scary and could cause a crash if low.\r\n\r\nI think our ultimate goal for the behavior should be this:\r\n- EKF becomes available faster - no GPS, only estimating height and attitude, not position and velocity.\r\n- Pre-arm check makes it impossible to arm before EKF is ready\r\n- Really, we should have a pre-arm check for \"home position set.\" It doesn't make much sense to allow an RTL (and especially not an RTL with a land) to a home position that was set in-flight.\r\n- We should probably just go into an \"indoor mode\" when you arm with no GPS. Play a different buzzer tone, regularly play a warning tone, and disallow non-manual modes until the user lands, disarms, and then arms again. \"Indoor mode\" should also be force-able by arming with a different stick gesture.\r\n- In the meantime, we should probably by default disallow arming before a home position is set. I'll make a separate issue."}}