# Relative altitude not zeroing in instrument panel

**URL:** <https://discuss.px4.io/t/relative-altitude-not-zeroing-in-instrument-panel/424>\
**Category:** Uncategorized\
**Created:** [May 14, 2016, 3:03am UTC](https://discuss.px4.io/t/relative-altitude-not-zeroing-in-instrument-panel/424 "2016-05-14T03:03:24Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Justin\_Cooper](https://discuss.px4.io/letter_avatar_proxy/v4/letter/j/e274bd/32.png) [@Justin\_Cooper](https://discuss.px4.io/u/Justin_Cooper)\
**Post date:** [May 14, 2016, 3:03am UTC](https://discuss.px4.io/t/relative-altitude-not-zeroing-in-instrument-panel/424/1 "2016-05-14T03:03:24Z")

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The instrument panel is not zeroing my relative altitude on startup is reading as -5m or so. Is it using GPS instead of baro or do I have another issue?

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**Author:** ![marimach77](https://discuss.px4.io/user_avatar/discuss.px4.io/marimach77/32/79_2.png) [@marimach77](https://discuss.px4.io/u/marimach77)\
**Post date:** [May 14, 2016, 3:05pm UTC](https://discuss.px4.io/t/relative-altitude-not-zeroing-in-instrument-panel/424/2 "2016-05-14T15:05:06Z")

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I have the same as @Justin_Cooper. After powering the copter on, relative altitude was -2m and after 4-5 minutes it was -15m.

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**Author:** ![Mark\_Whitehorn](https://discuss.px4.io/user_avatar/discuss.px4.io/mark_whitehorn/32/3533_2.png) [@Mark\_Whitehorn](https://discuss.px4.io/u/Mark_Whitehorn)\
**Post date:** [May 14, 2016, 3:32pm UTC](https://discuss.px4.io/t/relative-altitude-not-zeroing-in-instrument-panel/424/3 "2016-05-14T15:32:40Z")

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Does disarming and re-arming reset it?

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**Author:** ![Justin\_Cooper](https://discuss.px4.io/letter_avatar_proxy/v4/letter/j/e274bd/32.png) [@Justin\_Cooper](https://discuss.px4.io/u/Justin_Cooper)\
**Post date:** [May 14, 2016, 4:19pm UTC](https://discuss.px4.io/t/relative-altitude-not-zeroing-in-instrument-panel/424/4 "2016-05-14T16:19:41Z")

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no it does not. If I lift the plane up 5m it will zero. Its like its comparing GPS alt reading to QGC map altitude.

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**Author:** ![Justin\_Cooper](https://discuss.px4.io/letter_avatar_proxy/v4/letter/j/e274bd/32.png) [@Justin\_Cooper](https://discuss.px4.io/u/Justin_Cooper)\
**Post date:** [May 30, 2016, 4:05am UTC](https://discuss.px4.io/t/relative-altitude-not-zeroing-in-instrument-panel/424/5 "2016-05-30T04:05:24Z")

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until you arm the plane it goes off GPS alt so it’s showing you the erro. Then once it’s armed it zeros and uses baro. I think this is sorted out now.