We present the first survey of radio frequency interference (RFI) at the future site of the low frequency Square Kilometre Array (SKA), the Murchison Radio-astronomy Observatory (MRO), that both temporally and spatially resolves the RFI. The survey is conducted in a 1 MHz frequency range within the FM band, designed to encompass the closest and strongest FM transmitters to the MRO (located in Geraldton, approximately 300 km distant). Conducted over approximately three days using the second iteration of the Engineering Development Array in an all-sky imaging mode, we find a range of RFI signals. We are able to categorise the signals into: those received directly from the transmitters, from their horizon locations; reflections from aircraft (occupying approximately 13% of the observation duration); reflections from objects in Earth orbit; and reflections from meteor ionisation trails. In total, we analyse 33 994 images at 7.92 s time resolution in both polarisations with angular resolution of approximately 3.5 $^{\circ}$ , detecting approximately forty thousand RFI events. This detailed breakdown of RFI in the MRO environment will enable future detailed analyses of the likely impacts of RFI on key science at low radio frequencies with the SKA.

中文翻译：

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在默奇森射电天文台对 FM 波段的空间和时间分辨无线电频率干扰进行调查

我们在默奇森射电天文台 (MRO) 的低频平方公里阵列 (SKA) 的未来站点展示了无线电频率干扰 (RFI) 的首次调查，该观测站在时间和空间上都解决了 RFI。该调查在 FM 频段内的 1 MHz 频率范围内进行，旨在涵盖距离 MRO（位于杰拉尔顿，距离约 300 公里）最近和最强的 FM 发射机。使用工程开发阵列的第二次迭代在全天空成像模式下进行了大约三天，我们发现了一系列 RFI 信号。我们能够将信号分类为： 直接从发射器接收到的信号，从它们的地平线位置接收到的信号；来自飞机的反射（约占观察时间的 13%）；地球轨道上物体的反射；和流星电离轨迹的反射。总的来说，我们以 7.92 秒的时间分辨率分析了 33 994 张图像，在两个极化中，角分辨率约为 3.5 $^{\circ}$ ，检测大约四万个 RFI 事件。MRO 环境中 RFI 的详细分解将使未来能够详细分析 RFI 对使用 SKA 的低射频关键科学的可能影响。