Super Dual Auroral Radar Network (SuperDARN) radars operate in a coordinated but monostatic configuration whereby high‐frequency (HF) signals scattered from ionospheric density irregularities or from the surface of the Earth return to the transmitting radar where Doppler parameters are then acquired. A bistatic arrangement has been developed for SuperDARN radars in which HF signals transmitted from one radar are received and analyzed by another radar that is separated by a large distance (>1,000 km). This new capability was developed and tested on radars located in Oregon and Kansas. Numerous 3‐day bistatic campaigns have been conducted over a period extending from September 2019 through March 2020. During these campaigns three distinct bistatic propagation modes have been identified including a direct mode in which signals are transmitted and received through the radar side lobes. Direct mode signals propagate along the great‐circle arc connecting the two bistatic radar sites, reflecting from the ionosphere at both E region and F region altitudes. Two additional modes are observed in which HF signals transmitted from one radar scatter from either ionospheric density irregularities or from the surface of the Earth before propagating to the bistatic receiving radar. Ray tracing simulations performed for examples of each mode show good agreement with observations and confirm our understanding of these three bistatic propagation modes. Bistatic campaigns continue to be scheduled in order to improve technical aspects of this new capability, to further explore the physical processes involved in the propagation and scattering of HF bistatic signals and to expand the coverage of ionospheric effects that is possible with SuperDARN.

中文翻译：

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SuperDARN HF雷达的双基地观测：初步结果

超级双极光雷达网络（SuperDARN）雷达以协调但单基地的配置运行，从电离层密度不规则或从地球表面散射的高频（HF）信号返回到发射雷达，然后获取多普勒参数。已经为SuperDARN雷达开发了一种双基地布置，其中从一个雷达发射的HF信号被另一条相隔较大距离（> 1,000 km）的雷达接收并分析。这项新功能是在俄勒冈州和堪萨斯州的雷达上开发和测试的。从2019年9月到2020年3月，进行了为期3天的多站式运动。在这些活动中，已经确定了三种不同的双基地传播模式，包括直接模式，在该直接模式下，信号通过雷达旁瓣进行发送和接收。直接模式信号沿连接两个双基地雷达站点的大圆弧传播，在两个电离层的电离层反射E地区和F地区的海拔。观察到另外两种模式，其中从一个雷达发射的HF信号在传播到双基地接收雷达之前会从电离层密度不规则性或从地球表面散射。对每种模式的示例执行的光线跟踪模拟与观察结果显示出良好的一致性，并证实了我们对这三种双基地传播模式的理解。继续计划开展双基地战役，以改善这一新功能的技术方面，以进一步探索HF双基地信号的传播和散射所涉及的物理过程，并扩大SuperDARN可能产生的电离层效应的范围。