**6. Performance cluster of telematic applications using GNSS**

Transport telematics architecture [22] displays the arrangement of subsystems and functional blocks, including information relationships according to the defined point of view. The task also covers the selection of representative telematics applications ("*cluster*") that shows identical systems requirements.

Among the individual representative applications using GNSS (Global Navigation Satellite Systems) the following may be included:


Transport telematics architecture [22] displays the arrangement of subsystems and functional blocks, including information relationships according to the defined point of view. The task also covers the selection of representative telematics applications ("*cluster*")

Among the individual representative applications using GNSS (Global Navigation Satellite

 Securing the movement of a means of transport in a transport infrastructure (from the point of view of performance parameters within the GNSS, it is a question of securing accuracy, reliability, availability, integrity, etc., at exactly defined points of the transport infrastructure – the application lays high stress both on the locator proper and the information transmission and processing systems; the solution should comply with the "fail-safe" principle; for typical transport telematics applications we may refer to railway interlocking technology, monitoring the transport of dangerous goods, or

 Navigation of the means of transport in a transport network (from the point of view of performance parameters, it is a matter of coverage with a signal, time lag in on-line navigation, requirements as for the exactly working maps of an entire geographical area, requirements on the speed of information processing, both within a mobile unit and the processing centre, as well as minimisation of the delay when establishing the position – TTFF - Time to Fix Face); as typical transport telematics applications, the following may be referred to: the navigation of safety and rescue units for a localised

 Monitoring and operating the maintenance of transport networks (from the point of view of performance requirements, it is particularly a matter of an exact transport infrastructure information retrieval, interoperability of individual GIS (Geographical Information Systems) systems of various organisations dealing with maintenance, and achievement of high statistical accuracy in establishing position); as it concerns typical transport telematic applications, the following ones should be mentioned: mapping the river channel by means of a measuring ship, or measuring the carriageway parameters

 Monitoring the movement of persons and goods in a transport infrastructure (from the point of view of performance requirements, it is a matter of transmission and central processing of large amount of information from resources of various accuracy, fast identification of individual sub-sets of the objects of transport, sophisticated information processing in the centre, for instance, the "Floating Car Data"); as typical transport telematic applications, the following can be referred to: the use of taxi cabs, public transport passenger vehicles or other utility vehicles equipped with the GNSS systems for traffic flow modelling, or the use of localised mobile telephones for

 Transport infrastructure charging according to its utilisation (from the point of view of performance parameters, it is a matter of reliability, integrity and time lag because the GNSS system is used to calculate the amount of the charge and, furthermore, the application places demands on the "fail-safe" principle in terms of the distance covered – if there is an uncertainty about correct charging of the driver, the distance covered is

**6. Performance cluster of telematic applications using GNSS** 

monitoring the movement of means of transport at the airport.

accident place or dynamic and/or on-line automobile navigation.

by means of special measuring vehicles.

modelling the mobility of persons.

that shows identical systems requirements.

Systems) the following may be included:

not taken account of); as a typical transport telematic application, it is electronic charging of the transport infrastructure according to the vehicle parameters and distance covered.

As a follow-up to the completed analysis and decomposition of performance parameters to individual subsystems, a table can be obtained containing performance requirements of the above mentioned representatives as for the locator proper, telecommunications environment or the information processing centre.

### **6.1 Illustrative example - Assessment of telecommunications solution of GNSS monitoring system on airport surface**

Described system methodology can be demonstrated on the telematic application based on GNSS (Global Navigation Satellite System) developed for the airport area moving objects management with good potential to be integrated into the already operated airport monitoring and management system.

The service central server collects and processes data received from all service vehicles. The obtained information is combined with the data gained from the existing systems. Processed and obtained result is distributed not the only to the airport management, but as well as to each vehicle equipped with active On-Board Unit (OBU) equipped with display of relevant size and quality. Each OBU receives also the managerial data generated by either airport control system or by dispatchers. Principal schema of the subsystem organization is displayed on Figure 4.

Fig. 4. Telematic service structure (WL – wireless, A-SMGCS - Advanced Surface Movement Guidance & Control System)

An airport area is precisely and transparently regulated area. The telematic sub-system performance indicators are introduced in Table 2.


Table 2. Required Telematics Performance Indicators in airport application

Using a transformation method described in [14] - [16] the telematic performance indicator "accuracy" was identified as the performance indicator with the dominant impact on the whole system performance. Its dominance is caused by the specific character of studied application. The requested level of accuracy (see Table 2) must be reached for every object moving with speed up to 120km/hour, If 1m GNSS sensor accuracy can be reached (the differential GNSS alternative must be applied) 195ms remain for the delay caused by all devices including the potential error healing in case of any sub-system problem (all on probability level 99% - see table 2).

Mobile WiMax (IEEE Std. 802.16d) was identified as the only possible alternative of the wireless access solution for the critical areas of the airport. All the other available access systems like GSM based products DTMF, HSCSD GPRS and EDGE as well as UMTS were identified as inappropriate. WiFi system operated in the open frequency band does not provide any service quality guarantee. Table 3 displays the obtained dynamical parameters of the WiMax channel (ART – Average Round Trip delay) in two critical stages of the Signal to Noise Ratio (SNR)


Table 3. Principle parameters of the WiMax access

Even though WiMax was selected as the core mobile access system for the airport critical areas, the whole airport area coverage with this technology is not economical. Some of alternative access solutions (EDGE/GPRS/UMTS or even WiFi) for Mobile WiMax difficult/irrelevant areas can be applied, if system parameters of these technologies meet these areas system parameters requirements. For such case multi-path solution like CALM, IEEE 802.21 based or by authors announced adaptive multi-path alternative (see e.g. in [20] - [21].) are identified as the appropriate alternatives.

The L2 ring based solution of the terrestrial chain part with the local QoS management (Hirschman) was applied to fulfill time limits of the whole chain.

**Accuracy** 7.5m 99% - **Availability** 30s 99% after init. **Reliability** 36s 99% 3,600s **Continuity** 5s 99% 180s **Integrity** 5s 99% -

Using a transformation method described in [14] - [16] the telematic performance indicator "accuracy" was identified as the performance indicator with the dominant impact on the whole system performance. Its dominance is caused by the specific character of studied application. The requested level of accuracy (see Table 2) must be reached for every object moving with speed up to 120km/hour, If 1m GNSS sensor accuracy can be reached (the differential GNSS alternative must be applied) 195ms remain for the delay caused by all devices including the potential error healing in case of any sub-system problem (all on

Mobile WiMax (IEEE Std. 802.16d) was identified as the only possible alternative of the wireless access solution for the critical areas of the airport. All the other available access systems like GSM based products DTMF, HSCSD GPRS and EDGE as well as UMTS were identified as inappropriate. WiFi system operated in the open frequency band does not provide any service quality guarantee. Table 3 displays the obtained dynamical parameters of the WiMax channel (ART – Average Round Trip delay) in two critical stages of the Signal

> Site Visibility ART [ms] SNR [db] 1 LOS 45.6 33 2 LOS 47.1 32 3 NLOS 44.6 -26 4 NLOS 44.8 -27

Even though WiMax was selected as the core mobile access system for the airport critical areas, the whole airport area coverage with this technology is not economical. Some of alternative access solutions (EDGE/GPRS/UMTS or even WiFi) for Mobile WiMax difficult/irrelevant areas can be applied, if system parameters of these technologies meet these areas system parameters requirements. For such case multi-path solution like CALM, IEEE 802.21 based or by authors announced adaptive multi-path alternative (see e.g. in [20] -

The L2 ring based solution of the terrestrial chain part with the local QoS management

**probability level** 

**time interval** 

**limit value** 

Table 2. Required Telematics Performance Indicators in airport application

**Perform. Indicator** 

probability level 99% - see table 2).

Table 3. Principle parameters of the WiMax access

[21].) are identified as the appropriate alternatives.

(Hirschman) was applied to fulfill time limits of the whole chain.

to Noise Ratio (SNR)

The applied method nosily disqualified such communications "gurus" like the MPLS backbone terrestrial networking or GPRS/EDGE wireless access and combination of the wireless solution based on IEEE Std. 802.16d with terrestrial L2 switching solution with QoS management tools implemented were applied as core technology, they were tested and reasonable results were obtained. Critical issue, however, represent implementation of the effective decision processes to manage the multi-path solution to be kept in the required time limits – see [13] - [20].
