Location Standards

Cell ID	(Cellular Identification) Cellular tower identification that a handset is currently connected to on the network.
TDOA	(Time Difference on Arrival) E911-based technology that will apply to any cellular handset. Cost-effectiveness may not be it's feature but its location accuracy will be superior. This system requires an addition to every cellular tower on the network.
GPS	(Global Positioning System) Widely deployed but suffers signal loss and accuracy degradation under environmental circumstances. This is the most prevalent standard in the LBS industry.
A-GPS	(Assisted GPS) Combines cellular location and GPS to create a mesh location system. Get indoor location as well as poor signal location as well.

Applications
The suitability of the standard depends on the application. Also, the availability of the standard should also be considered. The majority of network carriers worldwide have not deployed any location systems at all for their subscribers. In such markets, Cell ID tracking and GPS would be the only choices. In the United States, federal regulations have given the industry a much needed push and have set a mandate for these location services. Also, some applications may require more granular location information than others. For example, if one needs to know exactly what address a target is at, Cell ID tracking would not suffice. Some technologies do not work well together, such as GPS and mobile handsets. Cellular handsets with a built-in GPS receiver often fail because of poor antennas and their subsequent failure to obtain an adequate GPS signal.


Comparative Analysis: GSM vs. CDMA

GSM Technology
Global System for Mobile Communications (GSM) is a world-leading standard in global wireless technology, and is used by many cellular network carriers in North America. GSM delivers high-quality and secure mobile voice and data to more than a billion subscribers across 190 countries worldwide. These standards are based on a Time Division Multiple Access technology. Benefits for GSM are the globally adopted standards and it's abundant features such as SMS, MMS and GPRS. The modular SIM Card concept gives GSM handsets and devices an interchangeability rivaled by no other.

CDMA Technology
Code Division Multiple Access) is owned and was developed by Qualcomm to compete against GSM. It uses spread-spectrum technology to provide greater user capacity but has a smaller cell radius. Next generation CDMA 1X technology will bring features such as high speed internet and enhanced messaging. Handset interchangeability has to be resolved by the carrier.



Comparative Analysis: GSM vs. GPS

			GSM		GPS
	Coverage		Available where there are towers (outdoors) and signal repeaters (indoors). Renown for signal building-penetration.		Uses "line-of-sight" (outdoors). Can be used anywhere where there is a clear line of sight. Real-time location tracking systems are also limited to cellular network availability for data transmission.
			Basically, GSM coverage is only limited to where the towers/repeaters are, whereas GPS is limited to environmental factors and "line of sight".
	Accuracy		Locations are determined by an algorithm combining signal strength and cell tower locations. Accurate up to 250 meters.		Coordinates are calculated using at least four geo-synchronous satellites. Accuracy depends on satellite service provider, and can be as accurate as 25 meters.
			Though GPS is more accurate in outdoor conditions, it cannot function in urban and indoor environments where satellite signals encounter degradation and loss.
	Cost		Hardware consists of the latest PCS technology that is available to the public. Service/software is a low monthly rate since it uses established cellular infrastructure and TCP/IP (GPRS) data transmission.		GPS hardware is always improving. Data transmission methods vary and can include older analog systems, two-way satellite or digital cellular systems such as GSM/GPRS or CDMA/1x. Service/software rates are similar.
			The bottom-line is that GSM uses existing mobile phone handsets and adds location functionality within its coverage area. This makes infrastructure requirements an absolute low and thus reduces implementation and deployment costs. However, GPS has unparalleled accuracy and hardware availability is rapidly improving.