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Decawave / uwb-dw1000

This repo contains the uwb-core driver for Decawave DW1000 transceiver.
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DW1000_DEVICE_TX_PWR does not match `dw1000_dev_cfg` power settings #3

Open fjmolinas opened 4 years ago

fjmolinas commented 4 years ago

The syscfg for the uwb-dw1000 sets the default TX_POWER for the device to -14.3:

https://github.com/Decawave/uwb-dw1000/blob/9503f2a394b870bd339668351afa6730da8da1c6/hw/drivers/uwb/uwb_dw1000/syscfg.yml#L28-L33

On the other side the default dw1000_dev_cfg power settings sets a gain of 9dB as the default, but if DW1000_BIAS_CORRECTION_ENABLED is enabled the correction is not based on the configuration settings in the default config but on the macros DW1000_DEVICE_TX_PWR and DW1000_DEVICE_ANT_GAIN.

https://github.com/Decawave/uwb-dw1000/blob/9503f2a394b870bd339668351afa6730da8da1c6/hw/drivers/uwb/uwb_dw1000/src/dw1000_hal.c#L77-L84

https://github.com/Decawave/uwb-core/blob/c6cf518e39a49f7084b229ee4ed7ab7ee80b2e5d/lib/uwb_rng/src/uwb_rng.c#L1027-L1039

I'm therefore quite unclear on what each of these values mean and what values should be considered for BIAS_CORRECTION

ncasaril commented 3 years ago

The DW1000_DEVICE_TX_PWR isn't used. It should be removed. Thanks for pointing this out.

edit: The bias correction does reference this value still as per your comments. However this hasn't been used in a while. I'd say do not use the bias correction. The receiver do oversteer if you have too much power coming into the antenna creating this bias, but this should only be a problem if you're having the antennas less than say 2m apart and high tx power. You can see if you're oversteering the receiver by checking the rssi.

fjmolinas commented 3 years ago

The DW1000_DEVICE_TX_PWR isn't used. It should be removed. Thanks for pointing this out.

edit: The bias correction does reference this value still as per your comments. However this hasn't been used in a while. I'd say do not use the bias correction. The receiver do oversteer if you have too much power coming into the antenna creating this bias, but this should only be a problem if you're having the antennas less than say 2m apart and high tx power. You can see if you're oversteering the receiver by checking the rssi.

Hi @ncasaril thanks for the explanation, that clarifies things for me. Cheers!