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I have a set of GPS data with Lat, lon and Course. I need to interpolate current value of course, using previous values of Course. The formula I am using is not accurate in curves.In C language I was trying the implementation. Formula I have used is : Current_Course = previous_Course + ((previous_course - previous_to_previous_course)* Ratio)

where Ratio is ratio of time difference and GPS update time.

Does anyone knows a better formula to interpolate course value. Thanks in advance.

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Did you search our site? Several questions exactly like this have appeared. – whuber Jan 29 '13 at 8:39
none of them matches the requirement, i think,as i need implementation in C language(doesn't know much language), and those answers takes end points and interpolate value between points.Here with 2 points or previous points ,we need next possible Course value(a bit accurate). – sphynx Jan 29 '13 at 9:30
I agree that although several versions of this question have appeared, none of the answers are adequate to your case. But please explain how your formula--which is linear interpolation--is "not accurate in curves" and how you would determine what is accurate. Are you perhaps looking for a statistical solution? A Kalman filter? A graphics spline? – whuber Jan 29 '13 at 18:29

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