Firefigher　indoor　location　system　is　crucial　for　determining　firefighter＇s　precise　position　in　a　burning　building.　When　a　firefighter　encounters　dangerous,　the　commander　could　immediately　obtain　his　position　information　by　the　system.　A　major　problem　with　the　personal　navigation　system　is　due　to　the　imprecision　of　sensor　measurement.　Altitude　information　is　important　for　the　rapid　rescue　operation　and　an　error　in　the　altitude　measure　will　greatly　prolong　the　golden　rescue　time.　In　this　paper,　we　propose　a　methodology,　called　elastic　correction　of　altitude　error,　for　reducing　the　navigation　altitude　errors　made　by　the　change　of　temperature　and　atmosphere　pressure.　Elastic　altitude　correction　is　based　on　a　synthesize　of　heading,　pitch　information　of　firefighter　detected　by　inertial　measurement　unit　(IMU)　sensor.　The　proposed　method　could　not　only　fulfill　the　requirement　of　firefighter　positioning　system,　but　also　useful　in　other　navigation　systems.