Applications can call on any of several types of positioning methods.
Using the mobile phone network: The current cell ID can be used to identify the Base Transceiver Station (BTS) that the device is communicating with and the location of that BTS. Clearly, the accuracy of this method depends on the size of the cell, and can be quite inaccurate. A GSM cell may be anywhere from 2 to 20 kilometers in diameter. Other techniques used along with cell ID can achieve accuracy within 150 meters.
Using satellites: The Global Positioning System (GPS), controlled by the US Department of Defense, uses a constellation of 24 satellites orbiting the earth. GPS determines the device's position by calculating differences in the times signals from different satellites take to reach the receiver. GPS signals are encoded, so the mobile device must be equipped with a GPS receiver. GPS is potentially the most accurate method (between 4 and 40 meters if the GPS receiver has a clear view of the sky), but it has some drawbacks: The extra hardware can be costly, consumes battery while in use, and requires some warm-up after a cold start to get an initial fix on visible satellites. It also suffers from "canyon effects" in cities, where satellite visibility is intermittent.
Do any current phones allow developers to implement the Location API based on the "mobile phone network"? I know GPS phones can take advantage of this functionality but wasn't sure if other, non-GPS phones could as well...
I worked with MS's MapPoint Location Server in the past and they have recently announced location data support from 1-2 US carriers. If it is so hard for MS to get carrier support, you can imagine how hard it is for individuals!
So, network location is an excellent idea but the carriers must make it less restrictive to use.
Originally posted by Greg Schwartz:
Was your work with MS Map Point at a J2ME level? Did this require GPS phones?
No, it is SOAP Web service -- so it is not tied to any client platform. (We are prototyping using .Net CF at this time though). The location data come from the carrier. So, there is no GPS needed. You can locate *any phone* in the network assuming that you have a privacy agreement with that user.
Originally posted by a sanjuan:
all j2me location service companies use gps phones right now, i believe...there are several of them as far as i know, espcially crowded around Nextel's IDEN.
I can start a "j2me location service company" and use MapPoint (carrier based location) as my backend today. Seriously, Russell Beattie's waveblog has J2ME/Symbian based client and uses carrier location info.
The carriers are required by government regulations (E911 initiative in the US) to locate their users and gather location data. They just do not make it available to small time developers like us. But if you have a business, you can deal with them.
I hope the carriers will wise up and set up developers programs for their location data in the future. There are so many possibilities!
It is only $500 for two-days of activities. Sounds very interesting. I wish I have time to go.
Originally posted by Michael Yuan:
I can start a "j2me location service company" and use MapPoint (carrier based location) as my backend today. Seriously, Russell Beattie's waveblog has J2ME/Symbian bas
very true, however there are several companies that actually have J2me-based implementations running on client fleets that i know of (or at least, i believe they've deployed them last i checked). it's fairly simple to create the apps, the problem is marketing them.
Prior posts mentioned that bigger companies can make use of a carrier's LBS data if an agreement is in place. Does anyone have any examples of this (i.e. a third party company working with a carrier to utilize their customer's location info)?
[ March 18, 2005: Message edited by: Greg Schwartz ]
I am working on an application that requires LBS provided by the network carrier, but it is in an early stage and I don't have a lot of info to share.
I found Ericssson's Mobile Positioning System to be the most accessible for developers: http://www.ericsson.com/mobilityworld/sub/open/technologies/mobile_positioning/index.html
If the network operators that concern you are using it (http://www.ericsson.com/mobilityworld/sub/open/technologies/mobile_positioning/faq/category1.html#q5)
you are in luck
Do you know if the carriers listed (i.e. Cingular and AT&T) currently support Ericsson's MPS or only have announced that they intend to support this? If I developed an application with MPS, could I deploy it today and have access to a handset's position data? Have you successfully tested your MPS application with any US carriers?
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