- (1) What is GPS?
- (2) How accurate is GPS?
- (3) Do I need a permit for using GPS?
- (4) What are the limitations for the use of GPS?
- (5) What’s the difference between GSM, and GPRS?
- (6) Can I use, your tracking devices when there’s no GPRS available in my area?
- (7) My area has no GSM network coverage. Can I use satellite communication?
GPS is the Global Positioning System of the U. S. Department of Defense (DOD) and consists of 24 satellites, which orbit the earth. A GPS receiver can compute location, velocity and time from the signals that are transmitted by the satellites. Our GPS/GPRS tracking units contain very sensitive receivers.
This depends strongly on the number and position of available satellites. If the receiver has a clear view at the sky, position accuracy is about 5 meters. When the view is blocked ,by e.g. large buildings or trees, accuracy will degrade.
No, there’s no permit required.
Any GPS-receiver needs to have a clear view at the sky. If this is not possible, e.g. in a parking garage, position accuracy will degrade or the receiver may not be able to produce a position-fix at all.
– GSM is circuit switched. If our tracking unit sends data via GSM, a channel is reserved (just like for voice communication) and data is transmitted. You’re charged for the time the channel is reserved.
– SMS is a short message service that’s send via the GSM network and can contain about 140 characters.
– GPRS is ‘always on’ and packet switched. Data is sliced into packets and transmitted through the GSM network. This is faster and cheaper because network capacity is used more effectively. You’re charged for the amount of data that’s being transported, not for the time that the unit is online.
In areas where there’s no GPRS coverage, some data can be transmitted by SMS, if GSM is available. It’s also possible to let the tracking units to store events in memory, which will be transmitted as soon as GPRS coverage is available.
Our GPS/GPRS tracking units are designed for use on a GSM/GPRS network and will not communicate with a satellite network. If there’s no GSM coverage, there’s no way to communicate with them. But we have GPS tracking units which are using satellite communication. They are able to communicate from anywhere in the world.
A RFID system consists of a tag made up of a microchip with an antenna, and an interrogator or reader with an antenna. The reader sends out electromagnetic waves. The tag antenna is tuned to receive these waves. A passive RFID tag draws power from the field, created by the reader and uses it to power the microchip’s circuits. The chip then modulates the waves that the tag sends back to the reader, which converts the new waves into digital data.
The big difference between the two is bar codes are line-of-sight technology. That is, a scanner has to “see” the bar code to read it, which means people usually have to orient the bar code toward a scanner for it to be read. Radio frequency identification, by contrast, doesn’t require line of sight. RFID tags can be read as long as they are within range of a reader. Bar codes have other shortcomings as well. If a label is ripped or soiled or has fallen off, there is no way to scan the item, and standard bar codes identify only the manufacturer and product, not the unique item.
Some have questioned whether electromagnetic fields (EMF) generated by power lines, mobile phones, WLAN, RFID readers and other wireless devices may be harmful to human health. The World Health Organizations research, as well as many other scientific studies, has shown that EMF exposure below the limits recommended in internationally adopted guidelines has not revealed any known negative health effects. To ensure a uniform benchmark for compliance, EPCglobal recommends adhering to the human exposure limits for EMF as developed by the International Consortium on Non-Ionizing Radiation Protection (ICNIRP) and recommended by WHO.