## 1 Introduction
Using conventional detection methods, the percentage of aliased data increases as the number of photons emitted by the target increases. This leads to more data being removed and can seriously reduce the efficiency of detecting the target's center of mass. For a given requirement for detecting errors, longer detection times are required. The conventional methods make it difficult to localize targets that emit too many photons because the aliasing data make up the majority of the overall data. Attempts need to be made to attenuate or  
Figure 1: Schematic diagram of XS detector structure. limit the photon count. However, even in the case of small photon counts, aliasing the data may occur. To handle aliased data for a Charge-Coupled Device (CCD) detector, there exist feasible ways [23; 24] to separate the aliased signals into several independent ones. But for an XS detector, it is hard for us to accurately separate the aliased data, especially considering the complex correspondence between the X and Y coordinates. Specifically, the XS anode consists of some anode strips in the X direction and some anode strips in the Y direction. When an electron cloud generated by a photon falls onto the XS anode plane, we can only obtain the charge of each anode strip. As shown in Figure 1, one anode strip can only obtain one set of charge data. We need to use these data to calculate the center of mass position of the photon. The processes of calculating the center of mass in the X direction and the center of mass in the Y direction using these data are completely independent. When there is only one photon in a single acquisition result, the X coordinate and Y coordinate of the center of mass can correspond. When two or more photons are included in a single acquisition result, as shown in Figure 2a,b, even if the center of mass can be calculated, it is very hard to realize the correspondence between the X and Y coordinates, and thus the actual positions of the photons cannot be obtained. In the detection process using an XS detector, each acquisition does not produce an image. Our goal is to employ the detector for target localization instead. For the center of mass detection problem and the target localization problem, neither the exact separation of the aliased data nor of the one-to-one X and Y coordinates is necessary. In this paper, we attempt to directly utilize aliased data to solve center of mass detection and target localization problems. For aliasing the data generated by the superposition of multiple photon signals, this paper analyzes their generation and data composition and finds that these aliasing data can be used for center of mass detection. In this paper, simulation experiments are designed to verify the effectiveness of aliasing data for center of mass detection. This means that in center of mass detection, the effect of the dead time on the detection results will be greatly reduced, and the number of photons need not be limited. In the simulation experiments, the results of retaining the aliased data for center of mass calculations are more accurate than the method of removing the aliased data for the same detection time. In long-range target localization problems based on cross-strip anode detectors, the retention method can obtain the target center of mass more efficiently and accurately. The retention method reduces the time required for detection and can be applied to objects with different brightness levels. Our research can provide some guidelines and support for the design and fabrication of XS detectors. We can add a new mode of operation to the detector. When the detector is working on target localization, we need the detector to acquire and output both aliased and non-aliased data. When the detector is used for other tasks, it only needs to output non-aliased data. Besides the design of new XS detectors, our work also has potential applications in the future to star sensors and detection in the Earth's shadow. A target in the Earth's shadow is usually dark because it cannot reflect sunlight.