# Anchor Selection, Quality Factor

[size=small][font=Arial]Hello, [/font][/size]

[color=#333333][size=small][font=Arial]I have two questions regarding the DWM 1001. Especially the first one is very important for my Master Thesis.[/font][/size][/color]

[color=#333333][size=small][font=Arial]1. Is there a possibility to disable the anchor selection? I would like to get all distances and not just the four already chosen by the Tag.
[/font][/size][/color]
[color=#333333][size=small][font=Arial]2. How is the Quality Factor calculated?[/font][/size][/color]
[color=#333333][size=small][font=Arial] [/font][/size][/color]
[color=#333333][size=small][font=Arial]Thank you very much.[/font][/size][/color]

[color=#333333][size=small][font=Arial]Robert[/font][/size][/color]

Hi Robert,

1. No it is not possible to disable anchor selection

2. The quality factor is calculated as follow :

In an ideal setup the tag will range with 4 anchors. We need 3 ranges to calculate a position. As there are 4 ranges, there are 4 groups of range leading to 4 different solution.

For each group, the tag will calculate a position using ranges to 3 anchors. It will then calculate the theoretical range from this position to the 4th anchors that wasnâ€™t used. This theoretical range is then compared with the measured range.

This process is repeated 4 times and the tag will keep the position for which the error between the theoretical range and the measured range is the smallest. If the error is > 0.50m, then the QF =0.

The QF value will be between 0 at 100, 100 corresponding to a null error (so an excellent setup).

Note that the value 50 is reserved. If the QF=50, it signifies the tag was able to range to only 3 anchors and as a consequence, error estimation could not be performed.

Let me know if you have any other questions,
Regards
Yves

[color=#111111][size=small][font=Tahoma, sans-serif]Hi Yves,[/font][/size][/color]
[color=#111111][size=small][font=Tahoma, sans-serif] [/font][/size][/color]
[color=#111111][size=small][font=Tahoma, sans-serif]Thank you for your answer. Are there other Parameters which I can get from the DWM1001 to evaluate my distance measurements? Maybe the RSSI Value or similar?[/font][/size][/color]
[color=#111111][size=small][font=Tahoma, sans-serif] [/font][/size][/color]
[color=#111111][size=small][font=Tahoma, sans-serif]Best Regards, [/font][/size][/color]
[color=#111111][size=small][font=Tahoma, sans-serif] [/font][/size][/color]
[color=#111111][size=small][font=Tahoma, sans-serif]Robert[/font][/size][/color]

Hi Robert,

It is not possible to get the RSSI out of the DWM1001 when using PANS.

QF is the main variable for quality evaluation.

Thank you,
Best regards
Yves