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

<p>Raw I/Q capture of the radar reflections originating from the&nbsp;<em>Grand R&eacute;seau Adapt&eacute; &agrave; la Veille Spatiale</em> (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 <span class="math-tex">\(f_s=1.92\text{ Msps}\)</span>.</p> <p>The capture was obtained from an <a href="https://es.aliexpress.com/i/1005003181244737.html">AntSDR E310</a> in 2r2t mode, tuned to 143.3 MHz.&nbsp;The&nbsp;antenna consisted of a minimal&nbsp;array&nbsp;of&nbsp;two&nbsp;<span class="math-tex">\(\lambda/2\)</span>&nbsp;vertical dipoles, with a&nbsp;<span class="math-tex">\(\lambda/2\)</span>&nbsp;spacing between both, with a design frequency of 143.050 MHz. The location of the antenna was&nbsp;40.45342176913288&ordm; N, -3.408497019619436&ordm; E</p> <p>The file was produced with SigDigger&#39;s &quot;Pluto/ANTSDR 2RX combined source&quot;, provided by the <a href="https://github.com/BatchDrake/AntSDRPlugin">AntSDR plugin</a>. This custom signal source modulates the samples of RX1 and RX2 by&nbsp;<span class="math-tex">\(-f_s/4\)</span>&nbsp;and&nbsp;<span class="math-tex">\(f_s/4\)</span>&nbsp;respectively, and sums both. This results in a spectrum that, once visualised from SigDigger, seems duplicated around the central frequency.</p> <p>This representation enables simple manipulation of both coherent channels with the existing software infrastructure: if we wanted to compare the phases&nbsp;of a channel at frequency&nbsp;<span class="math-tex">\(f_0\)</span>&nbsp;coming from both antennas, we would see the signal coming from RX1 at&nbsp;<span class="math-tex">\(f_0-f_s/4\)</span>&nbsp;and the signal coming from RX2 at&nbsp;<span class="math-tex">\(f_0+f_s/4\)</span>. It would suffice by multiplying the samples by two&nbsp;NCOs that cycle&nbsp;over phases&nbsp;<span class="math-tex">\(0,\pm\pi/2,\pi,\mp\pi/2\)</span>&nbsp;and applying an appropriate low-pass filter and decimation to the output of both.</p>