## 6 Conclusions and Future Work  
Our aim is to improve the accuracy, reliability and anti-jamming performance of location services in harsh environments. We strive to provide a solution not requiring elevation information in extremely harsh environments, such as forests, canyons, cities and high latitudes, with few visible satellites to improve the accuracy, reliability and anti-jamming performance of location services in harsh environments. We provide cm level navigation and positioning solutions. This paper is based on the technical requirements of ICN, based on the full-duplex mechanism or time synchronization technology of LEO satellites, assuming that the clock error between the LEO satellite and the receiver has been eliminated and gives a reference scheme for using three LEO satellites for high-precision navigation and positioning when the visible satellites are not complete. By introducing the concept of real ranging values and virtual ranging values, according to the different orbital satellites and switching times used, we conducted a simulation experiment to draw the following conclusions:  
1. Regardless of whether it is on the same orbit or different orbits or the original scenario and the comparison scenario, there is a tendency for the algorithm error to gradually increase as the alternate time increases. 2. Under  
Among these algorithms, the performance of the original scenario based on the integrated navigation algorithm based on INS+2-satellite alternate switching ranging under the LEO 3-satellite is the best, followed by the INS+LEO3-satellite alternate switching ranging algorithm under different orbits. However, each has its advantages and disadvantages and in actual business engineering, we should choose according to the actual situation. * Compared with conventional MEO constellation navigation systems, such as GPS, GNLONASS, Galilei and BDS, LEO constellations are more suitable for ICN solutions due to their low deployment cost and high navigation and positioning performance. * For multipath, NLOS and LOS interference, with the increase in MLNSR, the error of the algorithm also increases; for the environment of dual-modal Gaussian noise interference, the increase in the navigation error of the algorithm is also increasing; in the complex interference environment, the algorithm error is relatively large. In addition, in practical applications, since LEO satellites are subject to relatively large orbital perturbations, especially aspherical perturbation of the Earth and atmospheric resistance perturbations, the overall navigation and positioning results are acceptable. However, regardless of the kind of interference situation, our algorithm can guarantee very good robustness and can meet the demand of location services in challenging environments. Our algorithm is based on an LEO giant internet satellite system. At present, LEO satellites have excellent research prospects and practical significance. Therefore, our algorithm has practical significance. Relying on many LEO satellites, our algorithm can provide a new location reference solution for real-time location services and search and rescue in harsh environments, such as forests, gullies and canyons. In addition, compared with the traditional tightly coupled GNSS/INS integration algorithm, our algorithm not only has navigation and positioning accuracy and strong robustness, but also has strong anti-jamming performance. However, there is room for improvement in positioning accuracy in our algorithm. Thus, providing precise clock deviation-specific elimination technology will be the focus of our future research work. [PERSON] and [PERSON] conceived the conceptualization and algorithm, [PERSON] completed the implementation of the algorithm and the writing of the paper and supported the writing--review and editing. [PERSON] completed some preliminary simulations and did preliminary research and summary. [PERSON] provided theoretical guidance and suggestions for revision of the paper.