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manual:user_guide:tools:altitude [2015/04/01 16:26] – ToDo checked: later... mstupka | manual:user_guide:tools:altitude [2022/04/08 11:54] (current) – mstupka | ||
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- | ====== Altitude Manager ====== | + | {{ : |
---- | ---- | ||
- | <todo # | + | ===== About ===== |
- | ....................................... | + | <wrap box>Menu > Settings > GPS and location > Altitude manager</wrap> |
- | Altitude offset | + | |
- | Use altitude offset | + | |
- | Define offset between real and GPS altitude | + | |
- | Pressure sensor | + | Altitude manager enables to fine-tune obtaining altitude values from your mobile device. It is divided into three main tabs: |
- | Use pressure sensor | + | * **main settings** |
- | Measure precise altitude by pressure sensor | + | * **settings of altitude offset** |
- | .... | + | * **settings of pressure sensor** |
- | Altitude filter | + | ===== Settings ===== |
- | Apply filter to altitude. | + | Contains general switches of offset and pressure sensor |
+ | ==== SRTM data ==== | ||
+ | {{ : | ||
+ | * **No usage** - altitude values are acquired from GPS only | ||
+ | * **Optimize GPS altitude** - uses [[http://en.wikipedia.org/ | ||
+ | * **Replace GPS values** - uses [[http:// | ||
+ | <WRAP round alert > | ||
+ | **Warning for pilots**: optimizing or replacing GPS altitude by SRTM data is not recommended for activities when you are **not moving | ||
+ | </ | ||
+ | ==== Altitude filter ==== | ||
- | Offset | + | Applies filter to altitude measurement to reduce value fuzziness. Heavier filters cause less fuzzy altitude values but slower reaction on altitude changes. Scale ranges from no filtration to an ultra heavy filter. |
- | ........... | + | ===== Altitude offset ===== |
- | Enable | + | {{ : |
- | ... | + | Altitude |
- | Pressure | + | Locus Map can define this offset by three methods: |
- | ............. | + | * **Manual correction** - basic method used when the exact offset value is known |
- | Enable | + | * **Automatic correction** - method used in most cases - Locus Map can compute offset of the whole world from a Geoid model. This method is accurate enough for use in mobile phones and sufficiently precise for all locations (the offset slightly varies based on location). |
+ | * **Altitude NMEA correction** - mobile device communicates with GPS unit over a special messages called NMEA. These messages contain values of Geoid height that Locus Map can read and apply them to correct this offset.<wrap alert> | ||
+ | * **Enable also for Bluetooth GPS** - check this option if you use external GPS device | ||
+ | |||
+ | ===== Pressure sensor ===== | ||
+ | {{ : | ||
+ | Some devices are equipped with barometric pressure sensor. Barometric sensors measure atmospheric pressure very precisely which can be used for calculating relative altitude changes. I.e. if you know certain pressure at certain altitude you can calculate altitude changes between known and current position. | ||
+ | |||
+ | The pressure sensor must be calibrated to a known altitude value so that it can be used for real altitude value calculations. Locus Map offers several methods: | ||
+ | * **Automatic** - Locus Map uses GPS altitude or SRTM files altitude and current barometric pressure as basic values and relates all other measurements to these values. It also checks measured values in 2 hour intervals and eventually re-calibrates the pressure sensor. | ||
+ | * **Pressure | ||
+ | * **Altitude** - uses some other source of ground altitude - external maps, measuring, tourist guide posts, etc. as the reference. Locus Map then calibrates the pressure sensor according to this value. | ||
+ | < | ||
+ | </ | ||
- | Automatic | ||
- | Automatic calibration according to GPS |