How do GPS and Satellite Navigation work:

In summary

• satellites transmit signals to computer/sat nav in car
  
• sat nav system in car receives these signals
  
• depends on very accurate time references/atomic clocks
  
• each satellite transmits data indicating location and time
  
• sat nav system car calculates position based on at least 3 satellites
  
• at least 24 satellites in operation world wide
  
• sat nav system combines satellite information with mapping info