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Wednesday, October 23 2013, 08:17 AM
We are using BumbleBee radar for our human sensing research.
We accomplish to setup TinyOs environment for BumbleBee.Now we are able to gather the I and Q datas from BumbleBee.The I and Q datas like below;
00 FF FF 00 00 06 00 EE 3C DF 0B 1F 09 C3
00 FF FF 00 00 06 00 EE 3C E0 0A CF 09 DF
00 FF FF 00 00 06 00 EE 3C E1 0A B3 09 7D
00 FF FF 00 00 06 00 EE 3C E2 0A 6F 09 57 (last four ones are I and Q datas)
We noticed that ı and q datas comes with two component.We thought that they were low 8 bit and high 8 bit.
For example: 0A 6F are I datas. 0A high 8 bit. 6F low 8 bit.
09 57 are Q datas. 09 high 8 bit.57 low 8 bit.
Then we make them together and calculate I and Q datas.After this process we took the spectrogram of the datas.
I am attaching the spectrogram of the human walking through and against the radar.
Now I have some questions about BumbleBee.
Are we doing right while making I and Q datas together?(Low 8 bit ,High
8 bit thing)
After we get the I and Q datas should we make anything with the datas before calculating the spectogram for getting better visualization, noise elimination and clutter supression?

We would be so glad if somebody answer our questions.
Sincerely ,
Responses (3)
  • Accepted Answer

    Wednesday, October 30 2013, 05:43 PM - #Permalink
    The Telosb has a 12 bit adc which means you would expect a range of values from 0 - 4095. The values for I and Q in the above 4 data points do seem to be in the range of values generated by the bumblebee when 0A is treated as the most significant byte and B3 is treated as the least significant byte. I would assume therefore, you are doing the right steps (0x0A << 8 + B3) to process the data. Can you please provide us with a simple plot of sample value (after the conversion) vs sample number instead of the spectrogram and possibly more details on the environment the test was performed in like indoor vs outdoor, other objects in the scene and height of the radar from the ground ?

    Note that the radar also "sees" behind and to the sides albeit for shorter distances, but please keep this in mind when describing the environment.
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  • Accepted Answer

    Friday, November 15 2013, 05:30 AM - #Permalink
    Here are the inphase and quadrature phase plots.
    As our calculations ,the Prf value is found around 165.
    Is this correct?
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  • Accepted Answer

    Monday, December 23 2013, 12:55 PM - #Permalink
    What do you mean in this expression (0x0A << 8 + B3)?
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