{"action":"created","issue":{"url":"https://api.github.com/repos/digitalentity/cleanflight/issues/16","labels_url":"https://api.github.com/repos/digitalentity/cleanflight/issues/16/labels{/name}","comments_url":"https://api.github.com/repos/digitalentity/cleanflight/issues/16/comments","events_url":"https://api.github.com/repos/digitalentity/cleanflight/issues/16/events","html_url":"https://github.com/digitalentity/cleanflight/issues/16","id":89753129,"number":16,"title":"NAV - Althold problems","user":{"login":"digitalentity","id":11059099,"avatar_url":"https://avatars.githubusercontent.com/u/11059099?v=3","gravatar_id":"","url":"https://api.github.com/users/digitalentity","html_url":"https://github.com/digitalentity","followers_url":"https://api.github.com/users/digitalentity/followers","following_url":"https://api.github.com/users/digitalentity/following{/other_user}","gists_url":"https://api.github.com/users/digitalentity/gists{/gist_id}","starred_url":"https://api.github.com/users/digitalentity/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/digitalentity/subscriptions","organizations_url":"https://api.github.com/users/digitalentity/orgs","repos_url":"https://api.github.com/users/digitalentity/repos","events_url":"https://api.github.com/users/digitalentity/events{/privacy}","received_events_url":"https://api.github.com/users/digitalentity/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/digitalentity/cleanflight/labels/bug","name":"bug","color":"eb6420"},{"url":"https://api.github.com/repos/digitalentity/cleanflight/labels/in%20progress","name":"in progress","color":"009800"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":8,"created_at":"2015-06-20T10:45:21Z","updated_at":"2015-07-01T10:44:59Z","closed_at":null,"body":"Setup: use_midrc_for_althold=1, throttle input=1500, altitude drifts. Possible cause - insufficent I-term to compensate for thermals, algorithm flaw, barometer problems."},"comment":{"url":"https://api.github.com/repos/digitalentity/cleanflight/issues/comments/117598024","html_url":"https://github.com/digitalentity/cleanflight/issues/16#issuecomment-117598024","issue_url":"https://api.github.com/repos/digitalentity/cleanflight/issues/16","id":117598024,"user":{"login":"bk79","id":11835018,"avatar_url":"https://avatars.githubusercontent.com/u/11835018?v=3","gravatar_id":"","url":"https://api.github.com/users/bk79","html_url":"https://github.com/bk79","followers_url":"https://api.github.com/users/bk79/followers","following_url":"https://api.github.com/users/bk79/following{/other_user}","gists_url":"https://api.github.com/users/bk79/gists{/gist_id}","starred_url":"https://api.github.com/users/bk79/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/bk79/subscriptions","organizations_url":"https://api.github.com/users/bk79/orgs","repos_url":"https://api.github.com/users/bk79/repos","events_url":"https://api.github.com/users/bk79/events{/privacy}","received_events_url":"https://api.github.com/users/bk79/received_events","type":"User","site_admin":false},"created_at":"2015-07-01T10:44:59Z","updated_at":"2015-07-01T10:44:59Z","body":"mmm...that's not the solution let me explain a little how it works:\r\nkalman filter has the status and the inputs of the system, according to the actual status and the actual input it will evaulate next status of the system, and the measure incoming will correct pulling the system to converge to the filtered status:\r\nin small terms Kalman evaluate where we are, according to the previous condition of speed and position, and will correct any drift in the calculation when new measure arrives, this means that we're not using anymore the real measure but an estimation coming out from the Status matrix. So evaluation of the status of the system should be done every cycle, and update as much as possible to avoid drifting too much"}}