[Dev] [OT] indoor navigation (was: Tizen use of FIFO & Nice)

Łukasz Stelmach l.stelmach at samsung.com
Fri Dec 13 10:43:25 GMT 2013


It was <2013-12-13 pią 10:42>, when Ramasamy Kannan wrote:
> ------- Original Message -------
> Sender : Lukasz Stelmach<l.stelmach at samsung.com>
> 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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