NoneLOS

Wireless Connectivity Ultra-Wideband
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1

Hi;

I have question about none line of sight condition. During my experiments, I observed that as I decrese the volume of Anchors or in other words as I decrese the Anchor placement lead to a big bias errors in raw measurements. However, As I increse the Anchor placement or in other words a bigger volume the errors tend to offset (negative). How should I justify this phenomenon?

Any one has any idea?

2

Hello Sarah,

What do you mean exactly by decrease/increase volume covered by area? Are you speaking of range in X,Y axis or height in Z axis ? And how is that related with NLOS ?

When you increase the space between anchors, the granularity is better and the location engine performance is enhanced. This can be easily observed on the Z axis, with different height of antenna.

Thank you,
Best regards
Yves

3

Hi,

I meant the distance between Anchors. For example having 22 meter dimension or 33.
According to my experiment, 22 meter dimension is not good in none line of sight. Because even a small reflection makes the estimated ragnes greater than it must be. However, in 33 meter dimension, the ranges are not that much effected by multipath. there for the estimated ranges were less than it must be. I do not know what is the reason? Is that because the radio frequency behaviour or sth elase?

4

Hi Sara,

Do you have further information about the setup ? How do you get NLOS condition in such a small area.

Can you please send picture or video of you experiment ?

Thank you,
Best regards
Yves

5

Hi,
Yes, sure. I have uploaded the picture. I placed the Anchors in 2 meter high. And the office is 3*3 m dimennsion. so anchors are 3 meter apart from each other. In this experiment most of the ranging that I get was less than actual measurement. However, when I place the anchors 2 meter apart from each other ( 2 * 2 meter dimension) , Anchors heigh again 2 meter. I observed that most of the estimated ranges are longer than it must be.
I think that the Anchors height are important !!

6

Hi Sara,

How accurate are your anchors coordinates. Also, looking at the picture, it seems the LOS condition are fairly decent.

How much is the error against the measured range ?

Thanks
Yves

7

Hi,

the errors are not that bis. It is the question of beign posotive or negative. why the noise becomes negative?
I know if the nise is positive it measns that the estimated ranges are bigger than it must be. [mutilpath and high temperatue clock offfest] but if the error becomes negative it means that the the estimated ranges are less than it must be? How come the errors bechome negative then?
what factors effect it?

8

Hi Sarah,

The system accuracy is 10cm, is your error within those 10cm ?

Thank you,
Regards
Yves