D11.2: Mobility and LBS

Technology 

Accuracy 

Note 

Satellite-based positioning systems: 

GPS, Galileo 

>1m-15m 

1. The accuracy of satellite-based systems depends on the service/technology being used. 

2. GPS is mostly used outdoors since the signals are generally too weak to be received inside buildings. 

3. Satellite signals can be jammed or the accuracy can be altered by the government in case of a military emergency.

4. Examples of systems in use: A-GPS, GPS.

Cell-based mobile Communication Networks: 

UMTS (3G), GSM (2G) 

25m – 30km 

1. Most mobile network-based positioning technologies only offer a limited accuracy with regard to the positioning of the mobile device. 

2. The accuracy depends on the size of the communication cell, the mobile device resides in. In city centres, the diameter of a cell can be approximately 300 metres, in rural areas much larger cells (diameter up to approximately 30 km) exist. Additional technologies, for example using triangulation, allow more accurate positioning. 

3. Examples of systems in use: E-OTD, Cell-ID.

Other wireless Technologies: 

Radio Frequency Identification (RFID), WiFi, Bluetooth 

<1m – 50m 

1. These technologies use a similar approach as cell-based systems to determine the position of an entity. 

2. Several “base stations” are needed to perform the triangulation. However, the accuracy heavily depends on the technology and the amount of “base station” being present in the observed area  mostly these technologies are used indoors.

Sensor-based Systems: 

Optical sensors (infrared-based), biometrics (face recognition) 

Close proximity:
>10cm – several metres

1. Sensor-based systems resemble a conglomeration of different location technologies. 

2. Their accuracy and precision depends on the technology being used – also, the technologies themselves differ a lot in the way that they work (e.g. optical systems vs. wireless systems). 

Hybrid Systems 

N/A 

1. These technologies include systems that use combinations of different positioning technologies to offer a higher positioning precision. 

2. Example: Assisted GPS (A-GPS), combining GPS technology with external sensors (e.g. tachymeter) or cell-based positioning technologies (mobile phones, etc.).