The booming number of BeiDou Navigation Satellite System (BDS)-3 satellites, improvements in satellite technology, and signal designs are persistently expanding the Global Navigation Satellite System (GNSS) domains of application. With the modernization of BDS, multiple satellites broadcast new frequencies and signals which are necessary for precise point positioning (PPP) performance. In this study, the noise characteristics of BDS-3 signals are investigated alongside that of the Global Positioning System (GPS) and Galileo (GAL). Moreover, the paper evaluates the contribution of interoperable signals to PPP performance. The results indicate that the noise in BDS-3 modernized signals is comparable to that of the other navigation systems. In the case of PPP, BDS-3 positioning performance is noticeably improved as a result of adding GPS and GAL constellations. Thus, the less noisy BDS-3 signals could have a positive impact on PPP as the tracking stations with such signals densify.