## 5 Online Positioning Service  
CNES has set up a website dedicated to the demonstrator. Its internet address is [[http://www.ppp-wizard.net](http://www.ppp-wizard.net)]([http://www.ppp-wizard.net](http://www.ppp-wizard.net)) (accessed on12 July 2023 ). Figure 18 depicts an image of the main page of the website.  
This website provides all the material to monitor the demonstrator and to perform a positioning with integer ambiguity resolution on the user side:  
* a general description of the demonstrator, including descriptions of the new concepts such as the \"PPP-Snapshot\" mode,
* a set of PPP monitoring stations (for each station, an instance of the PPP-User software is running), the website displays the errors of the obtained solution with respect to an accurate reference and they are updated in real time and reflect the current performance of the demonstrator from the user side,
* links to download daily corrections (real-time or post-processed),
* an online positioning service,
* links to the presentations of the method,
* news of the project.  
The main purpose of the online positioning service is to show the quality of the products generated by the demonstrator and also to promote the different ambiguity resolution techniques presented in this paper. This service works like many other online positioning services, such as the NRCAN [17], the JPL [18] and the AUPOS [19] ones. The user uploads a rinex file along with some additional processing choices, and the service computes then returns the precise trajectory. The Figure 19 shows the web interface for the service based on the CNES PPP-WIZARD demonstrator.  
Figure 19: Online positioning service web page.  
Figure 18: The PPP demonstrator webpage.  
A database of GNSS products is maintained. The products are stored in a daily archive and can be either real-time or post-processed. Real-time products are generated every day at midnight, while post-processed products are generated on a daily basis with a latency of about 7 days. The start date of the archive is 1 January 2020. Each daily product archive contains the following files, which are a self-consistent set of data for further PPP processing: SP3, CLK, BRDM, atx, BIA, OBX. The post-processed or real-time products are chosen when the user sends its request, depending on the age of the measurements in the user rinex file.  
The uploaded file is checked for consistency. It must be under 50 MB. It can be of the following formats: rnx, crx,??d,??o, gz, or zip. The rinex file must contain at least dual-frequency GPS and/or GLONASS and/or Galileo constellation measurements at a maximal rate of 10 Hz. The maximum time span of the rinex file is 5 days. The header of the file is then checked, in particular the availability of \"MARKER NAME\", \"ANT # / TYPE\", \"ANTEINA: DELTA H/E/N\" fields. Indeed, the exact location of the positioning result depends on these fields.  
The rinex file is then sent to the queue of the positioning engine. Several positions can be processed at the same time. If the queue is full, the request is abandoned. The computation uses an instance of the User software [31] in forward/backward mode. Ambiguity resolution is activated. After the computation, a message is sent to the user to summarize the results. If dynamic positioning is requested, a link to download the trajectory (in NMEA format) is available. The Figure 20 gives an example of results for static and dynamic processing.  
As the wet tropo is estimated along with the receiver position, it is made available to the users by ticking the appropriate box on the online positioning service webpage.