Raw I/Q capture of GRAVES reflections caused by 2023 Perseids

Raw I/Q capture of the radar reflections originating from the Grand Réseau Adapté à la Veille Spatiale (GRAVES) radar in the 143.050 MHz frequency, and caused by the meteor ionisation trails during 2023 Perseids meteor shower. The file format is 2 x float32 (cf64), little endian and the sample rate is \(f_s=1.92\text{ Msps}\).

The capture was obtained from an AntSDR E310 in 2r2t mode, tuned to 143.3 MHz. The antenna consisted of a minimal array of two \(\lambda/2\) vertical dipoles, with a \(\lambda/2\) spacing between both, with a design frequency of 143.050 MHz. The location of the antenna was 40.45342176913288º N, -3.408497019619436º E

The file was produced with SigDigger's "Pluto/ANTSDR 2RX combined source", provided by the AntSDR plugin. This custom signal source modulates the samples of RX1 and RX2 by \(-f_s/4\) and \(f_s/4\) respectively, and sums both. This results in a spectrum that, once visualised from SigDigger, seems duplicated around the central frequency.

This representation enables simple manipulation of both coherent channels with the existing software infrastructure: if we wanted to compare the phases of a channel at frequency \(f_0\) coming from both antennas, we would see the signal coming from RX1 at \(f_0-f_s/4\) and the signal coming from RX2 at \(f_0+f_s/4\). It would suffice by multiplying the samples by two NCOs that cycle over phases \(0,\pm\pi/2,\pi,\mp\pi/2\) and applying an appropriate low-pass filter and decimation to the output of both.