The PECS-SISNeT project (complete title "Support of ESA Development of SISNeT-Related Software and Applications") started in October 2005 and was run by the Czech company Iguassu Software Systems, a.s. The main emphasis in the project was on development of next generation of SISNeT Data Server, the main pillar of SISNeT services.
1 Development of next generation Data Server
The objective was to re-engineer existing Data Server and add significant new services and functions. It had been divided into two consequential phases. The goal of first phase was to redevelop the SISNeT Data Server service using scripting language (Python) to increase performance, reliability and maintainability of the software. Furthermore include two new services – remote calculation of EGNOS corrections and remote calculation of user’s position based on given measurements. These server-side computations shall allow easier utilization of EGNOS corrections on hardware with weak computational force (such as smartphones). Upon completion of the first phase additional function were to be added in phase two – namely SISNeT Local Area Differential GPS Corrections, allowing users to further increase precision of their position using stations providing differential corrections. However the second phase and development of Local Area Differential GPS correction was suspended on ESA request during the development and objective changed to include support for EGNOS Data Acquisition System (http://www.egnos-edas.com).
|Fig.1: Data Server GUI. The new developed Data Server has a new Graphic User Interface (GUI) which allows visual orientation of all server’s subsystem and their current operation. The bottom part of the window is dedicated for real-time viewing of log, which is switched as operator chooses a subsystem to be observed.|
To test the new functions (mainly the position evaluation function), a number of testing scripts were developed for that purpose. To allow the new functions to be tested in the field a device driver for Pocket PC phones was developed. This driver acts as a virtual serial port driver that provides NMEA compliant data to connected application. As the application connects to this virtual SISNeT device, the driver connects to SISNeT Data Server and actual physical GPS navigation device. Then the driver read the measurements from GPS device and queries Data Server using these acquired data. The Data Server then computes the position with EGNOS corrections and sends the result to the driver, which then provides them to user application.
2 Development of SBAS TeACHER
SBAS TeACHER Is a new tool for manipulation of SBAS messages. It is capable of decoding SBAS messages, changing their content and encoding them back, as well as creating a new SBAS message from scratch. Editing of all types of messages is available in a very simple visual user friendly way. At first it was developed internally to test applications being developed in the context of SISNeT-PECS project, but when presented to ESA it had been seen as a useful process and made into a sub-WP with the output of a freestanding tool complete with an installer, to be made available to worldwide navigation community.
|Fig.2: SBAS TeACHER GUI (Graphic User Interface)|
The following description of this tool was used in presentation “The European Space Agency Free Resources for SBAS Education: Learning, Practicing, and Accessing the EGNOS Performances in Real-Time” presented by Felix Toran at ION GNSS conference:
The SBAS Tool for Education And Contributor to Harness EGNOS Research (SBAS TeACHER) was developed by Iguassu Software Systems under ESA contract, with the objective to allow decoding and encoding SBAS messages in a graphical and intuitive way, so that the SBAS message contents can be more effectively learned by students and new Engineers working in the SBAS field. At the same time, this tool was conceived as an SBAS message encoder / decoder to be used by SBAS Professional Engineers in different activities.
SBAS message definitions are highly optimized in terms of low bandwidth requirements – they have to be, because of the relatively low data bandwidth in the SBAS SIS broadcast. But this means that for the EGNOS uninitiated, deciphering what a message actually means for the first time may easily represent an uphill struggle.
……the features are a significant aid for students willing to understand the SBAS message definitions. The characteristics of SBAS TeACHER make it very useful also for GNSS Engineers needing to encode and decode SBAS messages in a quick and visual way.”
3 Support to EGNOS Real-Time Monitoring Network
During the SISNeT project Iguassu continued its participation and support to IMAGE/PERFECT network with its present monitoring station in Prague.
Iguassu continued to operate and maintain the EGNOS receiving station in Prague and provide to ESA and IMAGE/PERFECT the service of real-time data supply from central Europe 24 hours a day. To improve the stability of the monitoring, which was dependent on tools provided by the satellite receiver manufacturer, Iguassu company developed significantly improved and reliable tools to replace the supplied ones. Another objective of this WP was to find a partner and setup a real-time monitoring station east of Prague to enhance a grid of IMAGE network more to the east. For this second station it was decided to explore possibility of placement in Kosice, Slovakia, to enhance the grid as much east as possible. The placement of the station in the facility of University of Kosice was arranged and agreed upon by Iguassu, ESA and University of Kosice representative. However due to a unique opportunity to perform field tests of newly developed SISNeT services in Japan, and verify the possibility of using the MSAS, the Japanese SBAS equivalent of EGNOS, after agreement with ESA GNSS the transfer of the receiver to Slovakia was moved forward. In Japan Iguassu co-operated with the Japanese institutions including Kobe Aeronautical Satellite Centre of the Japan Civil Aviation Bureau (www.kasc.go.jp) and the renowned Yokosuka Research Park (http://www.yrp.co.jp/en/). The additional travel costs were covered by Iguassu internal funding, combining it with other events, namely the “EU Gateway to Japan”, sponsored by EU, and the Czech Japanese Science and Technology Days. These activities also led to Iguassu being invited by the vice-president of the Japanese space agency JAXA to spend a day with various departments and discuss future opportunities of co-operation in ESA programmes. It was agreed with ESA GNSS, that the second monitoring station establishment would therefore be postponed until such time all field test related to development of new Data Server are finished.
In addition to participation in IMAGE/PERFECT monitoring network, and recognizing the quality support and data supply, Iguassu was invited to join EXPERT monitoring network program and yet another receiver system has been provided to Iguassu by ESA and properly set-up in Prague providing additional data on EGNOS operation similar to IMAGE/PERFECT network, with the important difference that a cost-effective receiver is being tested for this purpose.
4 Further development of SISNeTlab and UAS
Objective of this work package was to continue improving SISNeTlab and User Application Software (UAS) functions developed during the first SISNeT-PECS project. The task was continuous on-demand developed, driven by anomaly-reports from users and changing conditions that could not have been foreseen at the time of the initial development. As an example of such development tasks was a change to be made to SISNeTlab modules due to a change in directory structure of YUMA almanacs provided by U.S. Naval Observatory last year. These directory structures and naming convention had been changed and all SISNeTlab modules that depend on YUMA almanacs ceased to work. After necessary changes to the code everything is in order again.
5 MOMO demonstration campaign
The goal of the work package was to perform a demonstration of the ESA’s MOMO equipment in Prague, in cooperation with Czech Blinds Organization to further promote results of this project. Iguassu was highly motivated and devoted very significant effort to overcome the obstacles related to unavailability of map formats compatible with the pilot device provided by ESA. Unfortunately, after lot of effort and progresses, Iguassu company has faced an important difficulty: the MOMO device did not include a cartography covering the Czech Republic. After working close with the MOMO manufacturer, under ESA management, Iguassu company has concluded the resolving the problem necessarily involves an extra investment. In view of that, ESA instructed us to abandon the effort and focus on SISNeT-related development which gained higher priority.
6 "A la carte" support to EGNOS Project Office
This work package had no fix list of objectives and was present in the project’s WBS in order to allow dynamic support to EPO activities as they may emerge. As an example of such tasks that had emerged is an improvement of Base Station, resolving a known limitation which caused the script to not reconnect upon a communications failure. The Base Station design was later improved by merge of Decoder and Base Station into a single application and re-designing the Base Station to a multithreaded application. As another example, there was a development to improve reliability and performance of FORWARD functionality developed in previous project to accommodate more broadcasting users. This way of assigning tasks to Iguassu at the instant the problem has arisen allowed for good problem-solution times, without a need for time-consuming definition of additional Work Packages, approval etc.
The PECS-SISNeT project successfully and timely accomplished its main objectives, namely development of
- advanced next generation Data Server with new level of services, allowing the use of cost effective terminals, and
- development of educational tools used around the world by students and professors.
Iguassu contribution to the ESA satellite navigation education tool set has been very well received. To quote once again from the ESA’s presentation at ION GNSS conference, here are some testimonials:
“A more ‘visual’ way to show the student how the system works”. The student can “visualize and
analyze the SBAS messages in a very easy and direct way”.
Dr. Jaume Sanz Subirana, Polytechnic University of Catalonia.
“The user interface is very simple and auto-explanatory, and very easy to manage for a non expert user”.
Pere Ramos, Polytechnic University of Catalonia.
“SISNeT User Application 3.1 is a powerful and user friendly tool that enables the users to monitor in real time the data coming from the SISNeT service; hence it is useful for testing the effectiveness of other SISNeT software applications. This tool has been used in our Laboratory to check the validity of out binary decode of the MOPS standard in the framework of the SISNeT driver that we are developing for our activities. One positive aspect of the tool is that no prior knowledge is required to start using it. In fact, its use is very simple and intuitive, also for users with only a general knowledge about EGNOS corrections.”
Fabrizio Dominici and Antonio Defina, NavSAS Group, Istituto Superiore Mario Boella.
“The SBAS tools provided by ESA are being used at the French Institute of Higher Education, SUPAERO, in the Satellite Navigation Course and the graphical explanation helps the students to better understand the different concepts and performance drivers. Some of the students are motivated to develop their final graduate thesis around these topics (e.g. contributing with SISNeTlab modules). The EGNOS Project Office Staff have also been kind to provide tutorials to students on EGNOS, SISNeT and the various tools for education. On the whole I would strongly recommend the professors of Satellite Navigation to use these tools during their courses.”
Prof. Michel Bousquet. Director of Aerospace Communications & Navigation programmes, SUPAERO, Toulouse
ESA valued Iguassu company´s initiative which led to promotion and awareness of the ESA SISNeT technology in Japan. ESA has also repeatedly expressed their satisfaction with the quality of results of project as well as the flexibility with which Iguassu company has reacted to externally created obstacles and the developing needs of the EGNOS project.
Project duration : 2005 - 2007
Approved budged : 330 640 EUR
Principal Investigator : Miroslav Houdek
Address : Iguassu Software Systems a.s.
Evropska 61, 160 00 Praha 6