How to calculate DS-TWR Delays?

[harun16]

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

[size=small][font=Arial] [/font][/size]
[size=small][font=Arial]I have built an own board with the “DW1000” and it works perfectly [/font][/size]
[size=small][font=Arial]I used the template with “ex_05a_ds_twr_init” and “ex_05b_ds_twr_resp” for my software with the preconfigured preamble length 1024, SFD size of 64 and data rate of 110Kbit/s.[/font][/size]
[size=small][font=Arial]Now I would like to change the preamble length to 2048 or 512 to see how this affects the measurements.[/font][/size]
[size=small][font=Arial]How would I have to change the delays (see below) for [size=small][font=Arial]e.g.[/font][/size] preamble lenght of 512?[/font][/size]
[font=Arial]At the moment, these are in the standard configuration:[/font]

[font=Arial Black][color=#c09100][size=large]Poll_RX_to_Resp_TX_Dly = 2600 us[/size][/color][/font]
[font=Arial Black][color=#2f5598][size=large]Poll_TX_to_Resp_RX_Dly = 150 us[/size][/color][/font]
[font=Arial Black][color=#c09100][size=large]Resp_TX_to_Final_RX_Dly = 500 us [/size][/color][/font]
[font=Arial Black][color=#2f5598][size=large]Resp_RX_to_Final_TX_Dly = 3100 us[/size][/color][/font]
[color=#2f5598][size=large] [/size][/color]
[font=Arial]I am aware that I have to calculate this myself, I need only one example, how it scales with preamble lenght.[/font]

[size=small][font=Arial]Many Thanks[/font][/size][font=Arial]! [/font]

[size=small][font=Arial]Best regards[/font][/size]
[size=small][font=Arial]Harun[/font][/size]

[size=small][font=Arial]Update: [/font][/size]
[size=small][font=Arial]I solved the problem myself, I can now use arbitrarily preambles.

Nevertheless many thanks[/font][/size]

[ruigomes]

Hello harun16,
I’m having some difficulties on this subject too.
I already tried some changes on the delays used but i never get it working. I know that this delays need to be “calculated”. I’m have a MDEK1001 dev and i want to compare the difference between the ss-twr and ds-twr and so i need to run this examples.
Can u share, if you please, the way that you solved that?
Many thanks,
Rui Gomes.

[ruigomes]

Hi,
Already find out the solution.
Thanks.

[BjoernS]

Could you share how you accomplished that? That would be nice! I have started with my thesis and it would be nice to include a different algorithm for more comparison and to include that in my evaluation.

[ruigomes]

Hi @BjoernS,
I used a excel sheet from this post below, so with that you could get an aproximate value.

DW1000 Power Calculator not working

The DW1000 Power Calculator java application seems to be having issues when it has always worked in the past. It runs but fails to calculate any values. If I run it from a command line I get the error: java.io.IOException: Server returned HTTP response code: 403 for URL: https://www.decawave.com//TWRCalculator/TWR_power_calculator.xlsx From memory 403 is access forbidden. And then when I click on calculate I get a null pointer exception on a call to ExcelInterface.writeCell So it looks like…

Hope i could help.
Cheers.

[BjoernS]

Hi @ruigomes ,

thank you this is pretty helpful as well! But actually I was looking for your solution of how to run ds-twr on the MDEK1001. I think I saw another post from you where I actually wanted to post this question but I accidentally used a wrong tab.

I intended to post this question under the following post from you:

MDEK1001 with ds-twr example

hello everyone! I’m trying the use the example of ds-twr with the mdek1001 development board (api docs and segger IDE,…) just to see the difference between ds-twr and ss-twr. I know that PANS 2.0 uses the ss-twr and all the “advantages” but i wanted to see if there is a big difference between these typologies. I’ve already built my firmware for ss-twr but when i tried to use the ds-twr example (init and resp exacly equal as the example) i can’t obtain measures (only changing the values of timeo…

I hope you can help me out here.

Thank you very much and have a great day.

[ruigomes]

Hey there @BjoernS,
I’m working on it too so now i dont have much to show too. But I followed another example (https://www.decawave.com/software/). Download the STM32 source code and on examples folder you have examples how to implement the different methods that you can use. I just used the ds_init (tag) and ds_resp(anchor) as a “template” and then changed the values of the delays and did work. Use that excel sheet so you can understand the time delays you need to implement because they will be dependent of your configuration (preamble, MHz, payload…).

Cheers.