**Input:** The positions of the anchors, the distances . |

**Output:** The positions of a set of determined sensors. |

Step 1: **Phase 1:** |

Set the anchors to be the initial set of sensors. |

Apply the extended geometric buildup algorithm. |

Step 2: **If** the percentage of the undetermined sensors is greater than TH. |

**Phase 2:** |

Find and determine an initial set of sensors. |

Apply the extended geometric buildup algorithm. |

Step 3: Align the sensors determined in the two phases. |