## 5 Conclusions  
In order to achieve the objectives of GNSS receiver design (availability, integrity, accuracy and electromagnetic vulnerability), the smart module proposed in this work allows the optimal selection of the best signal processing technique to use. The idea is to allow the receiver to process the received signal according to certain parameters: number of visible satellites, received signal level, elevation angle, geometric configuration of available satellites, navigation environment, etc. This module contains only the intelligent algorithm for selecting the best technique to use, namely, conventional HS-GNSS acquisition method or CD approach, while exploiting the best reference station for assistance and processing the best satellites.  
In this paper, the CD algorithm is optimized with a smart selection of the best satellites in the direct positioning technique instead of all visible satellites, in order to reduce the number of required computations.  
From the different obtained results, we can deduce that using the best satellites while combining all reference stations measurements may be sufficient to process the position solution instead of performing a process on all visible satellites. It can reduce the required computational burden (1.5 time faster) and at the same time have a good receiver sensitivity (loss of \(\pm\)0.7 dB-Hz), and also stay in a good margin of positioning accuracy. Indeed, this can reduce the complexity of implementation, but especially, it can minimize the energy consumption as part of a multi-GNSS receiver where tens of signals are present in the receiver antenna.  
The choice of the assigned weight costs may depend on several criteria on the quality of the corresponding reference receiver (low cost or professional receivers, acceptable margin of error, receivers that know their position with very high precision, etc.). In the practical case, the choice of the right technique will depend on the availability of the good receivers.  
The strategy of CD application as smart cooperative positioning meets the requirements of the complexity-sensitivity trade-off in CD approach. This concept allows us to take advantage from the existence of several receivers in good condition to help a receiver in deep urban area to estimate its position where it is usually impossible. Internet of Things (IoT) technology will also accelerate this possibility in the future.  
Future work for this research will focus on real-time testing with some receivers to verify the practical feasibility of this application. The assistance data update, taking into account the change of reference receiver, according to the evolution of the MS-RS distance should also be studied.  
Figure 10: Comparison of HPE between the four CD algorithms.  
**Author Contributions:** Basic ideas on the use of multiple receivers using the CD approach (new metrics, new expressions of detection equations, new receiver architecture using optimal parameters of other receivers), recording data and GNSS measurements; and analyzes and interpretation of results were conducted by the first author. The second author made the revisions of the papers in several stages with thorough and critical studies to improve the technical and scientific quality of the paper.  
**Funding:** This work is part of the project entitled \"Cognitive multi-antenna GNSS/INS Receiver Architectures and Methods for Indoor-Denied Navigation\". It is supported by the Natural Sciences and Engineering Research Council of Canada and Ecole de technologie superieure (LASSENA lab).  
**Conflicts of Interest:** The authors declare no conflict of interest.