Used GPS TomTom, NavMan Sat Nav


You've come to the right place to buy a used GPS or used Sat Nav system. The GPS, typically named Global Positioning System and originally named NAVSTAR, is a satellite navigation system used for determining one's explicit location virtually anywhere on earth. A GPS unit receives time signal transmissions from assorted satellites, and generates its exact position by triangulating the information. Checkout our great deals and grab yourself a discount used GPS or used Sat Nav.

TOMTOM ONE SAT NAV GPS WITH CASE CAR AND MAINS LEAD


TOMTOM ONE SAT NAV GPS WITH CASE CAR AND MAINS LEAD

Price: £44.00

NAVMAN W300 GPS BASED SPORT TOOL FOR WALKING


NAVMAN W300 GPS BASED SPORT TOOL FOR WALKING

Price: £9.99

TOM TOM Sat nav


TOM TOM Sat nav

Price: £3.19

TOM TOM GO 300


TOM TOM GO 300

Price: £5.50

TomTom One Classic UK and Europe Satellite Navigation


TomTom One Classic UK and Europe Satellite Navigation

Price: £62.00

GENUINE TOMTOM GO HOMEDOCK for 530 730 930 520 720 920


GENUINE TOMTOM GO HOMEDOCK for 530 730 930 520 720 920

Price: £4.99

TOMTOM GO 300 SAT NAV GPS UK+Full Europe MAP+Charger


TOMTOM GO 300 SAT NAV GPS UK+Full Europe MAP+Charger

Price: £54.95

TOMTOM XL 2 IQ ROUTES EDITION UK-IRE


TOMTOM XL 2 IQ ROUTES EDITION UK-IRE

Price: £94.29

NAVMAN ICN 650


NAVMAN ICN 650

Price: £6.52

Tom Tom One Uk And RoI


Tom Tom One Uk And RoI

Price: £50.00

USB laptop speakers for Sony VGN-NS20SS


USB laptop speakers for Sony VGN-NS20SS

Price: £17.99

USB laptop speakers for Sony VAIO Z21MN B 13.1


USB laptop speakers for Sony VAIO Z21MN B 13.1

Price: £17.99

Dashboard beanbag mount Mando 4301


Dashboard beanbag mount Mando 4301

Price: £17.99

USB laptop speakers for Sony VAIO VGN-Z21WN


USB laptop speakers for Sony VAIO VGN-Z21WN

Price: £17.99

Dashboard beanbag mount Mando 4100


Dashboard beanbag mount Mando 4100

Price: £17.99

USB laptop speakers for Sony VGN-BZ11MN


USB laptop speakers for Sony VGN-BZ11MN

Price: £17.99

USB laptop speakers for Sony Z31MN B


USB laptop speakers for Sony Z31MN B

Price: £17.99

USB laptop speakers for Sony VGN-Z11MN B PC


USB laptop speakers for Sony VGN-Z11MN  B PC

Price: £17.99

USB laptop speakers for Toshiba L300-20D


USB laptop speakers for Toshiba L300-20D

Price: £17.99

USB laptop speakers for Sony VGN-NR31J S


USB laptop speakers for Sony VGN-NR31J  S

Price: £17.99

USB laptop speakers for Sony VAIO Z31WN


USB laptop speakers for Sony VAIO Z31WN

Price: £17.99

USB laptop speakers for Sony Z21ZNX


USB laptop speakers for Sony Z21ZNX

Price: £17.99

USB laptop speakers for Toshiba Equium A210-17i160GB


USB laptop speakers for Toshiba Equium A210-17i160GB

Price: £17.99

USB laptop speakers for Sony VGNZ21ZN X.CEK


USB laptop speakers for Sony VGNZ21ZN  X.CEK

Price: £17.99

USB laptop speakers for Sony Z31WN B


USB laptop speakers for Sony Z31WN B

Price: £17.99

USB laptop speakers for Sony VGN-SR29VN S


USB laptop speakers for Sony VGN-SR29VN  S

Price: £17.99

USB laptop speakers for Sony VAIO Z11MN B


USB laptop speakers for Sony VAIO Z11MN B

Price: £17.99

USB laptop speakers for Sony VGN-NR32M S


USB laptop speakers for Sony VGN-NR32M  S

Price: £17.99

USB laptop speakers for Toshiba Portege A600-120


USB laptop speakers for Toshiba Portege A600-120

Price: £17.99

USB laptop speakers for Toshiba L300-19Q Cel-M 575


USB laptop speakers for Toshiba L300-19Q Cel-M 575

Price: £17.99


GPS Sat Nav


The GPS normally consists of 24 satellites in 6 orbital planes. Each satellite circles the earth two times every day. The satellites hold atomic clocks and continuously transmit the exact time, along with several other administrative information. The receiver does not necessarily need a precise clock, but it needs to have contact to four satellites in order to unambiguously compute its individual latitude, longitude, elevation and the explicit time. By comparing the signals from 2 satellites, the receiver can compute the diversity between the distances to the 2 satellites. Because the receiver also understands the exact locations of the four satellites, 3 such differences allow a system of 3 (nonlinear) equations for the 3 unknown latitude, longitude and the elevation. As soon as the receivers location and therefore distance to the satellites are known, the time signal sent out by 1 of the satellites allows to compute the exact time at the receiver's location. If elevation information is not essential, only 3 satellites need to be contacted.