lecture-7-cho_pte587_sensornet1-feb-24-2011

Transmitter 3211 speed of sound ultrasound receiver

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Unformatted text preview: ork must wake ­up with ­in 20 seconds Goal: •  Minimize Power consump;on 3/2/11 USC  ­ PTE587 29 What are the important characteris;cs? •  •  •  •  Transmit Power? Receive Power consump;on of the radio? Clock Skew? Radio turn ­on ;me? 3/2/11 USC  ­ PTE587 30 Solu;ons •  Minimize the ;me to check for “wake ­up” message •  “check” ;me must be greater than length of wake ­up message •  If data packets are used for wake up signal, then “check” ;me must exceed packet transmission ;me •  Instead use long wake ­up tone 3/2/11 USC  ­ PTE587 31 Basic Service Applica;ons 3/2/11 USC  ­ PTE587 32 Examples of Basic Services •  Localiza;on •  Time Synchroniza;on •  Data Aggrega;on 3/2/11 USC  ­ PTE587 33 Sensor Network Localiza;on •  GPS Localiza;on –  Use the GPS coordinates •  Addi;onal GPS units •  High Cost in Area and Energy •  Not always available •  GPS ­less Localiza;on –  Find Rela;ve Angle •  Where the angular vectors meet –  Find Distances and es;mate coordinates •  •  •  •  3/2/11 Use Radio and/or Ultrasound Addi;onal localiza;on algorithm Low Cost in Area and Energy Available within range USC  ­ PTE587 34 Ultrasound in Embedded System •  Imaging –  Baby in the womb –  3 ­D Internal Imaging •  Echoloca;on –  Imitate Bat or Dolphin –  Obstruc;on avoidance Robots •  Distance Measurement –  Time of Arrival 3/2/11 USC  ­ PTE587 35 Time Difference of Arrival •  TDoA of Radio and Ultrasound •  Range is smaller of radio and ultrasound •  Accuracy on the order of cen;meters •  Mul; ­path effects easier to detect 3/2/11 USC  ­ PTE587 UCLA AHLos Syste...
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This note was uploaded on 05/31/2012 for the course PTE 587 taught by Professor Alejandrobugacov during the Fall '11 term at USC.

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