Galileo Performances

GALILEO
Title	Galileo Performances
Author(s)	GMV
Level	Basic
Year of Publication	2011

Galileo system is a space-based global navigation satellite system (GNSS) that provides reliable positioning, navigation, and timing services to users on a continuous worldwide basis freely available to all. The Galileo performances are different for each service. For the Galileo Open Service (OS) no specific requirements of integrity are applicable. The performances for horizontal positioning accuracy at 95% for a dual-frequency receiver are 4 m (8 m for vertical accuracy), with an availability of the service of 99%.

In the case of the Galileo Safety of Life (SoL) and the Galileo Public Regulated Service (PRS), the performance requirements include horizontal and vertical accuracy, integrity, continuity and time to alert for different service levels. The availability of the service should be 99.5% for both services.

Galileo Service Level

Galileo is a civil system, operated under public control. Its missions include:

• Implementing an independent Global Navigation Satellite System (GNSS) that will fit in with and operate alongside existing and planned navigation and communication systems to provide both enhancements and redundancy;
• Improving the European infrastructure, particularly for multi-modal transport, while providing a global high-quality civil Position-Velocity-Time (PVT) capability;
• Supporting the special needs of safety of life and other applications and anticipating the needs of value-added suppliers in creating new markets and applications.

To a large extent, these mission requirements have been formally expressed in terms of the services that Galileo will make available or will support. These service levels are:

• Open Service (OS) - providing positioning, navigation and timing services, free of charge, for mass market navigation applications and competitive to the GPS Standard Positioning Service and its evolutions;
• Safety of Life (SoL) – compliant to different standards in the aeronautical, maritime and rail domains. The SoL includes Integrity and Authentication capabilities. The SoL include service guarantees;
• Commercial Service (CS) - generates commercial revenue by providing added value over the Open Service, such as by dissemination of encrypted navigation related data (0.5 kbps), ranging and timing for professional use - with service guarantees;
• Public Regulated Service (PRS) - for applications devoted to European/National security, regulated or critical applications and activities of strategic importance. The PRS will provide robust and encrypted signals, under Member States control.
• Search and Rescue Support Service (SAR) - provides assistance to the COSPAS-SARSAT system (space system for search of vessels in distress/search and rescue satellite-aided tracking) by detecting Emergency Beacons and forwarding Return Link Messages to the Emergency Beacons.

All the above services are named “Galileo-Satellite-only services”, as they will be provided by means of the so-called Galileo Global system component. It will be possible to enhance the performances of the Galileo satellite-only services, with the addition of local or regional component.

Galileo Service Level Perfomances

From Galileo Mission High Level Definition

Parameter	Galileo Service Level
	OS/CS				SoL	PRS
	SU			DU (E5a/L1)	Aeronautical & Vehicle User (E5b/L1)	SU		DU (L1/E6)
	E5a	E5b	L1			L1	E6
Lateral accuracy (95%, m)	24	24	15	4	4	15	24	6.5
Vertical accuracy (95%, m)	35	35	35	8	8	35	35	12
Velocity accuracy (95%, m/s)	0.2			0.2	0.2	0.2		0.2
Timing Accuracy (ns)	N/A			30	N/A	N/A
HAL (m)	N/A				12	N/A		20
VAL (m)	N/A				20	N/A		35
TTA (s)	N/A				5.2	N/A		10
Integrity Risk	N/A				2.10-7 / 150s	N/A		2.10-7 / 150s
Continuity	N/A				1-8.10-6 / 15s	N/A		1-8.10-6 / 15s
Availability (%)	99.5			99.5	99.5	99.5	99.5	99.5