# A Novel Satellite PRN Code Assignment Method Based on Improved RLF Algorithm
## 6 Conclusions  
Facing hundreds of LEO navigation enhancement satellites in the future, in order to shorten the storage resources and acquisition time of the navigation receiver, we put forward the idea of several LEO satellites sharing the same PRN code. We investigated the  
Figure 15: Diagram of sub-satellite points in different satellite orbits. These two different colors represent two satellites with different orbits. The points are satellite positions. The circles show the range in which the satellite PRN codes can be received on the ground. benefits of this novel method compared with the current method of assigning a unique PRN code to each satellite. The conclusions are summarized as follows:  
1. It is feasible and meaningful for several satellites sharing the same PRN code to save storage resources and reduce the satellite acquisition time of the receiver. 2. The RLF algorithm is effective for calculating the minimum number of PRN codes, and the improved-RLF algorithm accelerates the calculation speed. 3. In terms of satellite orbital parameters of polar-orbiting or walker constellations, the higher the altitude is, the more PRN codes needed. If other satellite parameters remain the same, no matter what the orbital inclination is, the minimum number of PRN codes remains the same. 4. In terms of hybrid constellations, we recommend that, after calculating the minimum number of PRN codes for each polar-orbiting or walker constellation separately, the minimum PRN code number of a hybrid constellation will be equal to the sum of the minimum PRN code numbers of the partial constellations that make up the hybrid constellation. Overall, if this new technology is applied, the storage resources of the receiver will be, at most, one-third of the previous value, and likewise, the average satellite acquisition time will be, at most, one-third of what it used to be. This new method can also greatly reduce the design difficulty of PRN code. Conceptualization, W.W., Y.T. and L.B. ; methodology, W.W.; validation, W.W., Y.T. and G.W. ; resources, L.B. and G.W. ; writing--original draft preparation, W.W. and Y.T. ; writing--review and editing, L.B., G.W., Y.M. and L.Z. ; funding acquisition, G.W., Y.M. and L.Z. All authors have read and agreed to the published version of the manuscript. This work was supported, in part, by the Key Research Program under Grant 2019-JCQ-ZD-342-00 and the Pro-research Project for Equipment of General Information System under Grant 315067105. Not applicable. The authors declare no conflict of interest. * [PERSON] et al. (2022) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] LEO-constellation-augmented multi-GNSS real-time PPP for rapid re-convergence in harsh environments. _GPS Solut._**2022**, _26_, 29. [CrossRef]
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