GPS
Wikipedia: How it works - simple introduction
A GPS receiver calculates its position by measuring the distance between itself and three or more GPS satellites. Measuring the time delay between transmission and reception of each GPS radio signal gives the distance to each satellite, since the signal travels at a known speed. The signals also carry information about the satellites' location. By determining the position of, and distance to, at least three satellites, the receiver can compute its position using trilateration. Receivers typically do not have perfectly accurate clocks and therefore track one or more additional satellites to correct the receiver's clock error.
Much speculation and many ideas have been proposed for the OLPC and GPS, the sections in this page have been harvested from the site to unify the subject.
NOTE: At the time of this harvesting of other people's ideas, there is no known intent to include anything related to GPS technology in the laptop.--Xavi 15:12, 19 January 2007 (EST)
GPS as an (unpopulated) Optional
- (Originally in USB peripherals)
GPS receivers with volume of about 1 cm^3 and a power consumption of less than 100mW (while continuously tracking!) are available today. These devices will provide a very high additional value for a small fraction of users.
Please evaluate the implications of reserving about 4 cm^2 PCB space for a through hole (not SMD) mountable GPS module (using bit-banged serial IO via general purpose IO pins, and the GPS module being not end-user mountable).
- Note that the target users don't need GPS to know where they are. If GPS was needed for a classroom situation or for some school project (mapping the fields around the village) then the OLPC already supports GPS through USB. Either a GPS that emits NMEA through RS-232 connected to a USB-serial port or a Bluetooth GPS that talks to a USB-Bluetooth dongle.
- USB ports are there for a VERY good reason
- What do you mean "don't need GPS to know where they are" ? What is the typical cost of each type of USB GPS? (and please sign comments!) Sj 19:41, 13 July 2006 (EDT)
- Call it $100 for USB enabled GPS units, less in bulk. But GPS can be used for a vast number of projects and issues, ranging from mapping and land surveys (not having to take anyone's word for where community property begins and ends!) through navigation and logistics. That said, I think this should be USB and not inside the device. We don't want some unfriendly government tracking these units -- or do we? GPS is a dual-use technology, after all, and I have had the thought that one of these kids laptops would make a dandy IED detonator. clarka 13 October 2006