## 1 Introduction
Multi-sensor inner FOV stitching has the advantages of expanding the FOV and increasing the coverage width while ensuring high resolution, but it is easily affected by factors such as focal plane stitching errors, camera optical system distortion, and satellite attitude changes. In order to increase the ground coverage width to a greater extent, the remote sensing satellite adopts the multi-camera outer FOV stitching method. The traditional multi-camera outer FOV stitching method is to install multiple cameras on the same satellite platform with overlapping FOV. For example, the Gaofen-1 (GF-1) satellite launched in 2013, as the first satellite of China's high-resolution Earth observation system, is equipped with two cameras with a resolution of 2 m (panchromatic)/8 m (multispectral). Images with the ground coverage width of 60 km can be obtained by outer FOV stitching. In addition, the satellite is also equipped with four wide FOV cameras (WFV) with a resolution of 16 m installed in vertical orbits, which can obtain an image with a width of 800 km after the outer FOV is stitched [9; 10; 11]. The main disadvantages of the multi-camera outer FOV stitching method are the requirements on satellite platform performance, payload weight, and cost. These problems make the method unsuitable for small satellites. With the improvement of the performance of micro-nanostatellites, it is proposed to use the images obtained by multiple satellites of the constellation to stitch together to increase the ground coverage width. For example, Planet Labs launched a large constellation of 3U cubesats, also known as pigeons, with more than 150 currently in orbit. The Flock satellite constellation utilizes differential drag control to complete coverage imaging of the Earth every day with a resolution of 3.7 m [12; 13]. However, this approach requires complex satellite deployment and mission mobilization to reduce overlap [14; 15]. Using satellite agile maneuverability to perform planned multi-strip stitching imaging is a new wide-swath imaging method brought by the development of agile satellites. The high-resolution optical remote sensing satellites in the United States are basically agile satellites, which use high maneuverability to increase the single-track wide swath of high-resolution satellites. For example: GeoEye satellites and WorldView satellites [16]. In addition, France's Pleiades satellite [17] and China's SuperView-1 satellite [18] are also agile satellites with high maneuverability. Take the SuperView-1 satellite as an example. The high-resolution camera (panchromatic 0.5 m/multispectral 2 m) carried on the SuperView-1 satellite has a width of only 12 km, but it can achieve stitching imaging of up to 5 strips, covering an area of 60 km \(\times\) 70 km. This method places high demands on the maneuverability of the satellites and requires a lot of mission planning and scheduling. In summary, multi-sensor inner field of view stitching, multi-phase outer field of view stitching and agile imaging based on satellite maneuverability all have their own advantages, but they all fail to solve the mutual constraints of ground resolution, ground coverage width, and load weight. Under the premise of ensuring high resolution and ultra-large width, there is an urgent need for a new imaging mode that reduces costs. Referring to the foreign microwave cone scanning imager [19; 20; 21; 22; 23; 24], we propose a novel optical cone and pendulum scanning imaging mode. The method uses a single-detector optical area array camera to perform frame stitching imaging by using camera swing and satellite spin motion. There are also more precise control methods to support the satellite spin motion [25]. In this paper, firstly, a single-camera constant speed optical cone and pendulum scanning imaging mode is designed.