CIR_PWR value is zero

Wireless Connectivity Ultra-Wideband
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1

Hi,
For calculating receive power using the equation mentioned in section 4.7.2 in user manual, I get rx_diag.maxGrowthCIR value is zero and log10(zero) yields -inf as receive power.
What will be the reason and how this situation will be tackled?
Any help will be appreciated.

2

Hi ,
Your problem description is rather vague.
What HW are you using? and what software?
Are the two boards able to communicate with each other? Are you running the standard TWR program for ranging? Have you loaded the Leading Edge Detection ,LDE? If not loaded it will also give you zeros
We have an example program called 02c_rx_diagnostics for diagnostics, please have a look or even use that program .
Also see APS022 , our debugging application note to check your RX events.

Regards
/Leo

3

Hi Leo,
Thanks for your reply.
I am using TREK1000 to implement TWR for distance calculation and intended to detect and mitigate NLOS error in distance calculation. I loaded decawave example source code Anchor (dw1000_api_Anchor\Src\examples\ex_05b_ds_twr_resp\ex_05b_main) and tag (dw1000_api_Tag\Src\examples\ex_05a_ds_twr_init\ex_05a_main) in two boards and its able to communicate with each other.I used tag as such with no changes and it transmit messages and in anchor side after receiving poll message I added one function to check timestamp quality of received signal.I followed decawave application note 3 for calculating confidence value from NLOS detection metrics - probability of NLOS, Likelihood of undetected early path and saturation metric and used decawave usermanual for calculating first path power and receive power. If either of the confidence value from NLOS detection metrics or power difference (receive power - first path power) falls into NLOS category, that received message is detected as NLOS and it should be mitigated for reducing error in range calculation. cir_pwr

4

Hi
As you have TREK and are able to load sample code on thw boards, could I ask you to load EVK1000 software on two boards and use PC decaranging?
The presentation attached shows what is possible with EVK1000.
ARM code and PC Decaranging can be fetched from our website.

Regards
/Leo

Decaranging CIR_EVK.pdf (267.2 KB)

5

So have you solve this problem? I have encountered that CIR_PWR is zero for some time. if you could help, reply to me and Thanks very much.