2014/10/15 下午 10:07:40

iphone Programming Glossary: drift

Indoor navigation hardware/software requirements for iOS

http://stackoverflow.com/questions/15732181/indoor-navigation-hardware-software-requirements-for-ios

of the user. Needs to be initialized and calibrated regularly by another absolute positioning technique. Subject to drift so accuracy degrades quickly over time. Upside is its very cheap no extra hardware or initial survey phase are needed. UWB..

Gyroscope vs Accelerometer?

http://stackoverflow.com/questions/3089917/gyroscope-vs-accelerometer

or dead reckoning allowing you to find the relative physical location of the device. Note that all inertial systems drift so its not stable in the long term . In short gyroscopes measure rotation accelerometers measure translation. There is a..

High-resolution timer for iPhone?

http://stackoverflow.com/questions/3540234/high-resolution-timer-for-iphone

NSDate. NSDate isn't even guaranteed to not go backwards occasionally when ntp does its thing. Devices can have clock drift. It the iOS device drifts fast a few seconds then when NTP corrects this drift you will see the clock suddenly go backwards.. guaranteed to not go backwards occasionally when ntp does its thing. Devices can have clock drift. It the iOS device drifts fast a few seconds then when NTP corrects this drift you will see the clock suddenly go backwards a few seconds. Very bad.. does its thing. Devices can have clock drift. It the iOS device drifts fast a few seconds then when NTP corrects this drift you will see the clock suddenly go backwards a few seconds. Very bad for timing use. mach_time uses a counter that doesn't..

Getting displacement from accelerometer data with Core Motion

http://stackoverflow.com/questions/4449565/getting-displacement-from-accelerometer-data-with-core-motion

and within a short period of time. But than after a few seconds you will run into trouble because your object is drifting away. Now you will enter the difficult part of the solution which I failed to handle eventually within the given time.. forces or virtual forces . This is some strategy to react on several bad situations triggering the object to drift away although the device remains fixed no native speaker I mean without moving in your hands. The most troubling one is..

What is a runloop?

http://stackoverflow.com/questions/4947556/what-is-a-runloop

It does mean though that a Timer will never be 100 accurate. As well if you have a timer repeating every second it'll drift over time. Also instead of directly triggering a drawing event. Your timer should invalidate the view that needs updating..

iPhone - understanding iPhone rotation

http://stackoverflow.com/questions/5170010/iphone-understanding-iphone-rotation

angles without any 90簞 singularities or other beasty stuff. The possible drawback of this solution might be a slight drift because of error propagation and the lack of feedback from your virtual space. Example if you have your iPhone on a table.. displacment of the cube when you put the phone back in starting position. EDIT Forgot some part To get rid of the drifting effect you only need a way to express your last object's real position q1 as a quaternion i.e. coordinates in your app..

Is there any way to remove the small bias along the gravity axis in the accelerometer data

http://stackoverflow.com/questions/9074947/is-there-any-way-to-remove-the-small-bias-along-the-gravity-axis-in-the-accelero

small bias along the gravity axis in the accelerometer data Similar to this question CMDeviceMotion userAcceleration drift I'm using CMDeviceMotion.userAcceleration in iOS5 SDK to plot its x y z components over time. Like the above post I see.. ios5 accelerometer core motion share improve this question First you need some external reference that does not drift such as GPS. Then you have to perform sensor fusion Kalman filter comes to mind . Otherwise you cannot remove the bias and..