Hi, We are observing a time difference of arrival (TDOA) variation between two E320 devices using PCM signals.
* The devices receive with zero hardware delay delta to the RF inputs. * Both devices have the latest filesystem installed (UHD 4.8). * Matched filtering is applied to estimate the time of arrival of the pulses. * The time of arrivals are subtracted to compute the TDOA. * Internal GPSDO PPS and 10 MHz clocks are used. * cgps reports GDOP values around 2.0 for both devices. * Multiple 60-second test runs have been conducted. * A deviation of around 150 ns in TDOA between the initial and final estimations across the radios is observed. We know that the matched filtering estimation and other imperfections follow a stationary Gaussian distribution with a 20 ns sigma (and a constant mean per run). We verified this behavior on the same setup using two B210 devices with external Ettus-supplied GPSDOs. The B210s report similar GPS performance to the E320s. What could be the cause of the non-stationary behavior observed on the E320s?
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