It was <2013-12-13 pią 10:42>, when Ramasamy Kannan wrote: > ------- Original Message ------- > Sender : Lukasz Stelmach<[email protected]> > Date : Dec 13, 2013 14:38 (GMT+05:30) >> It was <2013-12-13 pi? 04:20>, when Ramasamy Kannan wrote: [...] >>> Here are some sensor event interval requirements for different >>> applications. >>> >>> Gaming -20ms >>> User Interface - 50ms >> >> 100 ms won't hurt. >> >>> GPS - 100ms >> >> Most GPS receivers I've seen provide updates once a second. Some of them >> could be switched to 5Hz updates at most. As far as I can tell even >> aviation GPS receivers don't update more than 10Hz. >> >>> Some indoor navigation GPS applications need to be very accurate >>> interms of calculating the position of the mobile device. So they may >>> go for lower sensor event intervals. >> >> Accuracy in case of these has nothing to do with timing. Those systems >> which use WiFi signals calculate the position based on signal strength. >> WiFi cards do not send updates more than once a few seconds. In case of >> dedicated systems they probably have their own MCUs and behave more or >> less like GPS. > > Indoor Navigation applications use sensor fusion algorithms on raw > accelerometer, gyroscope, magnetometer, barometer sensor data along > with GPS data to estimate the position of the mobile phone > user. Sensor Fusion uses extended kalman filter signal processing > which normally gives better estimation of position, height, > orientation data when sampling rate is increased for example to 25Hz > or 50Hz or 100Hz. There are lots of research papers online which > provide information on this. > > Example paper:- > http://kom.aau.dk/~nfog04/imu/Articles/26%20Quaternion-Based%20Extended%20Kalman%20Filter%20for%20Determining%20Orientation%20by%20Inertial%20and%20Magnetic%20Sensing.pdf
I admit I haven't follow development in this field and last time I read about these method they were described as very prone to noise and quickly diverging. I talked to a guy who developed a positioning system using accelerometers and gyroscopes and he told me the system passed the orbit of the moon after like 15 minutes of laying still on his desk ;-) It's nice to know there has been significant improvement here. -- Łukasz Stelmach Samsung R&D Institute Poland Samsung Electronics
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