###### Abstract  
The space segment of all the five satellite systems capable of providing precise position services, namely Bel'Dou Navigation Satellite System (BDS) (including BDS-3 and BDS-2), Global Positioning System (GPS), GLOBul NAVigation Satellite System (GLONASS), Galileo and Quasi-Zenith Satellite System (QZSS), has almost been fully deployed at present, and the number of available satellites is approximately 136. Currently, the precise satellite orbit and clock products from the analysis centers European Space Agency (ESA), GeoForschungsZentrum Potsdam (GFZ) and Wuhan University (WHU) can support all five satellite systems. Thus, it is necessary to investigate the positioning performance of a five-system integrated precise point positioning (PPP) (i.e., GRECJ-PPP) using the precise products from different analysis centers under the current constellation status. It should be noted that this study only focuses on the long-term performance of PPP based on daily observations. The static GRECJ-PPP can provide a convergence time of 5.9-6.9/7.2-6.3/1.6-3.7-1 min and a positioning accuracy of 0.2-0.3/0.2-0.3/1.0-1.1 cm in east/north/up directions, respectively, while the corresponding kinematic statistics are 6.8-8.6/3.3-4.0/7.8-8.1 min and 1.0-1.1/0.8/2.5-2.6 cm in three directions, respectively. For completeness, although the real-time precise products from the analysis center Centre National d'Etudes Spatiales (CNES) do not incorporate QZSS satellites, the performance of real-time PPP with the other four satellite systems (i.e., GREC-PPP) is also analyzed. The real-time GREC-PPP can achieve a static convergence time of 8.7/5.2/11.2 min, a static positioning accuracy of 0.6/0.8/1.3 cm, a kinematic convergence time of 11.5/6.9/13.0 min, and a kinematic positioning accuracy of 1.7/1.6/3.6 cm in the three directions, respectively. For comparison, the results of single-system and dual-system PPP are also provided. In addition, the consistency of the precise products from different analysis centers is characterized. precise point positioning: multi-constellation integration: real-time position solutions: post-processed position solutions: precise satellite products: consistency +
Footnote †: journal: remote sensing  
should be noted that the PPP technology can be classified into the short-term PPP and the long-term PPP. Usually, the long-term PPP can provide centimeter-to-millimeter-level static position accuracies and decimeter-to-centimeter-level kinematic position accuracies after a processing time of several hours. All the reported accuracy of PPP in this study is only valid for the long-term performance. For the performance of short-term PPP, many findings in this aspect were described in the literature [6, 7, 8]. The short-term PPP using high-rate observations can detect the wave motions (over a short period of time, such as a few minutes) at the millimeter level accuracy in the horizontal components and at the sub-centimeter level accuracy in the vertical component when taking the displacement waveforms derived from an inertial measurement unit (IMU) as the reference, but the collection of GNSS data in the static mode for tens of minutes is needed in advance. The high-rate GNSS data are strongly correlated between the epochs, and thus they are beneficial to detect the wave motions, for example, the seismic wave motions. However, this can provide very little information for the quality improvement of the estimated receiver positions. The long PPP solutions are still needed for the solution convergence and for obtaining the high-quality absolute positions as well as other parameters, such as zenith total delays. GLObal NAvigation Satellite System (GLONASS) with a full constellation including 24 operational satellites was completely revitalized in 2012. Since then, the available GNSSs have been extended to two satellite systems, namely Global Positioning System (GPS) (with 32 operational satellites) and GLONASS.