The PR³ (Payload for Radio-interferometry and Radiation measurement on Rockets) payload was designed for, and flown on, the REXUS 25 rocket and performed two experiments inside a single module.¹

The first experiment uses radio-interferometry to precisely localize the sounding rocket during flight. An accuracy in the range of 10 cm was expected with an update rate of 1 kHz. In order to achieve this, three antennas mounted on the outside of the module transmit unmodulated carrier signals at three distinct wavelengths around 70 cm. These carrier signals are received by six ground stations placed around the Esrange launch site. Each ground station uses three antennas to perform phase-difference measurements to compute a vector pointing in the direction of the rocket. All six vectors are combined to find a solution of the rocket’s position. Since three different frequencies are transmitted, three sources can be identified. This should allow for attitude and accuracy estimation of the system.

The second experiment was designed to evaluate whether ionizing radiation can be detected with three types of commercial off-the-shelf camera sensors. A scintillator-based radiation sensor designed for cubesats was also onboard to serve as a reference radiation sensor. Furthermore, three types of commercial off-the-shelf cameras are evaluated. The cameras have different properties with respect to the technique (CCD versus CMOS) as well as different resolutions. Particle interactions are processed on-board and are made available via a telemetry link. Raw data is stored for post-flight processing. The scintillator sensor is used as a reference sensor to compare the camera results against. We present the technical aspects of the experiment design and the obtained results.

PR ³（用于火箭的无线电干涉和辐射测量的有效载荷）有效载荷是为REXUS 25火箭设计并飞行的，并在单个模块内进行了两个实验。^1个

第一个实验使用无线电干涉术来精确定位飞行中的探空火箭。预期精度为10 cm，更新速率为1 kHz。为了实现这一目标，安装在模块外部的三个天线以70厘米左右的三个不同波长发送未经调制的载波信号。这些载波信号由Esrange发射场周围的六个地面站接收。每个地面站都使用三个天线执行相差测量，以计算指向火箭方向的矢量。将所有六个向量组合起来以找到火箭位置的解。由于传输了三个不同的频率，因此可以识别三个源。这应该允许对系统的态度和准确性进行估计。

第二个实验旨在评估是否可以使用三种类型的商用现货相机传感器检测到电离辐射。还为船体设计了基于闪烁体的辐射传感器，用作参考辐射传感器。此外，还评估了三种类型的商用现货相机。相机在技术方面具有不同的属性（CCD与CMOS）以及不同的分辨率。粒子相互作用在板上进行处理，并可以通过遥测链接使用。原始数据被存储用于飞行后处理。闪烁传感器用作参考传感器，以比较相机的结果。我们介绍了实验设计和获得的结果的技术方面。