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I don't see the cell phone idea working simply because the raw data from the radio receiver is not exposed to the user application. Similar for the FM radio in
by oakwhiz 10y ago
I don't see the cell phone idea working simply because the raw data from the radio receiver is not exposed to the user application.
Similar for the FM radio in cell phones - all you really get is the demodulated and processed audio. Software defined radios have the best opportunity to work because they have direct access to the RF samples in the time or frequency domain. Unfortunately there is a cost associated with purchasing and running one, so the operators of the experimental data collectors would have to be volunteers willing to put in the resources. It's not as easy as installing an app, you need a piece of hardware running all the time and the data must be processed before uploading to the Internet.
- avian 10y agoSome Wi-Fi hardware does allow access to signal before demodulation, for debugging purposes or channel monitoring (e.g. [1]). But this is usually limited in some way (e.g. you can only get a limited number of samples or FFT bins). The authors also talk about correlating such samples with GPS time with sub-microsecond precision. This is most likely impossible. GPS receiver is separate from the Wi-Fi interface and I doubt they share any kind of low-level synchronization in a smartphone. [1] https://wireless.wiki.kernel.org/en/users/drivers/ath9k/spectral_scan https://wireless.wiki.kernel.org/en/users/drivers/ath9k/spec...