Altering/disabling the GPS functionality does not mean that you will be unable to be found. Via triangulation of your radio, location may be given up to someone if they are determined enough.
GPS is provided by either the device or your paired phone. More than likely, you will want to keep GPS functionality operational. It is not required, but does assist in some of the time calculations at a bare minimum.
On `gps_attempt_time`, `gps_update_interval`, &`position_broadcast_secs` when you set these to `0` you are not disabling these features.
On `gps_attempt_time` and `gps_update_interval`, the value `0` will be interpreted by the device as the default of **30 seconds**. On `position_broadcast_secs` the value `0` will be interpreted as the default of **15 minutes**.
If you wish to disable any GPS features, see below for more information.
If set, this node is at a fixed position. The device will generate GPS updates at the regular `gps_update_interval`, but use whatever the last lat/lon/alt it saved for the node. The lat/lon/alt can be set by an internal GPS or with the help of the mobile device's GPS.
Determines whether the device should accept 2D GPS fixes. By default, only 3D fixes are accepted (during a 2D fix, altitude values are unreliable and will be excluded).
Determines how the GPS coordinates are displayed on the OLED screen.
| Value | Description |
| :---: | :---------: |
| GpsFormatDec | GPS coordinates are displayed in the normal decimal degrees format: DD.DDDDDD DDD.DDDDDD |
| GpsFormatDMS | GPS coordinates are displayed in the degrees minutes seconds format: DD°MM'SS"C DDD°MM'SS"C, where C is the compass point representing the locations quadrant |
| GpsFormatUTM | GPS coordinates are displayed in Universal Transverse Mercator format: ZZB EEEEEE NNNNNNN, where Z is zone, B is band, E is easting, N is northing |
| GpsFormatMGRS | GPS coordinates are displayed in Military Grid Reference System format: ZZB CD EEEEE NNNNN, where Z is zone, B is band, C is the east 100k square, D is the north 100k square, E is easting, N is northing |
| GpsFormatOLC | GPS coordinates are displayed in Open Location Code (aka Plus Codes) |
| GpsFormatOSGR | GPS coordinates are displayed in Ordnance Survey Grid Reference (the National Grid System of the UK). Format: AB EEEEE NNNNN, where A is the east 100k square, B is the north 100k square, E is the easting, N is the northing |
Determines the amount of time that a GPS fix should be allowed to take. The default is every 30 seconds. If you increase this value, it will allow the device that amount of time in seconds to acquire coordinates. If the device is unable to get a fix, it will turn off until the next interval. GPS coordinates are updated every [`gps_update_interval`](#gps_update_interval) seconds.
Determines GPS maximum DOP accepted (dilution of precision) Set a rejection threshold for GPS readings based on their precision, relative to the GPS rated accuracy (which is typically ~3m) Solutions above this value will be treated as retryable errors! Useful range is between 1 - 64 (3m - <~200m) By default (if zero), accept all GPS readings
| GpsOpUnset | **Default**: operates the same as `GpsOpMobile`. |
| ~~GpsOpStationary~~ | Note: This mode was removed, because it is identical go `GpsOpMobile` with a `gps_update_interval` of once per day This node is mostly stationary, we should try to get location only once per day, Once we have that position we should turn the GPS to sleep mode This is the recommended configuration for stationary 'router' nodes |
| GpsOpMobile | This node is mobile and we should get GPS position at a rate governed by `gps_update_interval` |
| GpsOpTimeOnly | We should only use the GPS to get time (no location data should be acquired/stored) Once we have the time we treat `gps_update_interval` as MAXINT (i.e. sleep forever) |
| GpsOpDisabled | GPS is always turned off - this mode is not recommended - use `GpsOpTimeOnly` instead. |
Determines how often should the device should attempt to acquire a GPS position (in seconds). The length of time the device is allowed to attempt to acquire GPS coordinates each interval is set using [`gps_attempt_time`](#gps_attempt_time). The default is every 30 seconds.
| LocUnset | **Default**: operates the same as `LocEnabled`|
| LocEnabled | The device is sharing its location (or the paired phone's location) |
| LocDisabled | The device is not sharing its location (if the unit has a GPS it will default to only get time - i.e. [`GpsOpTimeOnly`](#gps_operation)) |
The GPS updates will be sent out every `position_broadcast_secs`, with either the actual GPS location, or an empty location if no GPS fix was achieved. This defaults to broadcast every 15 minutes.
`position_broadcast_smart` will send out your position at an increased frequency only if your location has changed enough for a position update to be useful.
Complements `position_broadcast_secs` (doesn't override that setting) but will apply an algorithm to more frequently update your mesh network if you are in motion and then throttle it down when you are standing still. If you use this feature, it's best to leave `position_broadcast_secs` at the default.
As an example, if you configure your radio to use **Long Range / Fast**, if you have traveled at least 144 meters and it's been at least 61 seconds since the last position update, a new position broadcast will be sent out. If you've moved less than 144 meters, we will broadcast the position based on the value of `position_broadcast_secs`.
| Long Name | Update every x-seconds | Update distance traveled (meters) |
| :---: | :---------: | :---------: |
| Long Range / Slow | 88 | 150 |
| Long Range / Fast | 61 | 144 |
| Medium Range / Slow | 30 | 41 |
| Medium Range / Fast | 30 | 30 |
| Short Range / Slow | 30 | 30 |
| Short Range / Fast | 30 | 30 |
Note: A person walking in a straight line will take about 90 seconds to travel 150 meters. That walking speed estimate was used as the baseline for the formula used.
The device will continue to acquire GPS coordinates according to the `gps_update_interval`, but will use the last saved coordinates as its fixed point.
It may take some time to see that the change has taken effect. The GPS location is updated according to the value specified on `gps_update_interval` and the mesh will be notified of the new position in relation to the `position_broadcast_secs` value.
