GNSS will study the operational requirements for current and future satellite navigation systems in the road, rail, maritime, aviation and survey sectors. Backed by a user group, the study will define the operational and functional system requirements as a basis for recommended optimum architectures along with a cost-benefit analysis. A scenario will then be proposed for the transition from the current system which depends on the use of military systems (GNSS 1) to a fully civilian system (GNSS 2). Benefits of the navigation system are expected in all forms of transport and in many other applications requiring accurate position and/or time determination.
A recognised and regulated civil global navigation satellite system (GNSS) does not currently exist. However a great many users are making unregulated use of signals from GPS for position fixing and for navigation in numerous application areas. A regulated quasi civil satellite navigation system (GNSS1) is currently being developed in Europe that will allow significantly more users to benefit from the existing military satellite systems. This will be accomplished through the provision of redundancy and augmentation to overcome the deficiencies of the "core" systems. With adequate diversity and independent monitoring, some of the "institutional" issues may become less significant for those non-safety critical applications. For the future, a fully civil controlled satellite navigation system (GNSS2) has been proposed.
This study will be undertaken in support of the European GNSS programmes, and has the following objectives.
1) Define the operational requirements for a GNSS.
2) Define the functional requirements for a GNSS.
3) Recommend an optimum GNSS1 system architecture.
4) Recommend an optimum GNSS2 system architecture.
5) Recommend a GNSS1-GNSS2 transition scenario.
The fulfilment of these objectives is crucial if future GNSS1 and GNSS2 systems are to be developed, which meet as many user requirements in a cost effective manner.
The definition of the operational requirements for a GNSS must consider the potential user groups for a GNSS system, since the requirements of the different user groups will define the levels of performance and safety that the system is required to meet. In addition the functional requirements are crucial to the viability of the operation of the GNSS system. These requirements include validating the safety of the system, definition of test and acceptance validation criteria and recovery of the development and operating costs.
Having identified the operational and functional requirements for a GNSS system, encompassing both GNSS1 and GNSS2, potential architectures can be developed and the optimum architecture selected. The selection process will take into account the ability of each architecture to meet the operational requirements of each user group, and the associated cost-benefit for each architecture. In addition it is important to consider the transition between GNSS1 and GNSS2 in identifying potential GNSS2 architectures, to ensure that a seamless transfer between the systems takes place. This requires the development of potential GNSS1-GNSS2 transition scenarios.
Funding SchemeCSC - Cost-sharing contracts
WC2B 6TE London
28760 Tres Canios
HA7 4LY Stanmore
GU1 4UL Guildford