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GPS for Elixir

XGPS runs as an application and will start along with you application, and connect to an serial port to get GPS data.

## Installation

If [available in Hex](, the package can be installed as:

  1. Add `xgps` to your list of dependencies in `mix.exs`:

    def deps do
      [{:xgps, "~> 0.1.0"}]

  2. Ensure `xgps` is started before your application:

    def application do
      [applications: [:xgps]]

  3. To make an effort to be platform independent, XGPS uses [nerves_uart]( for the dirty details. Please make sure to follow the instructions for nerves_uart to make this compile and run on your system.

## Usage: start
### Manually
Simply call:


### Config
Add a line like this in you config:

  config :xgps, port_to_start: {"name-of-port"}

### Config with init
If you are using the Adafruit Ultimate GPS you can add:

  config :xgps, port_to_start: {"name-of-port", :init_adafruit_gps}

This will send a series of commands to your GPS to configure it.
The following commands are then sent:
- "$PMTK313,1*2E" => enable SBAS
- "$PMTK319,1*24" => Set SBAS to not test mode
- "$PMTK301,2*2E" => Enable SBAS to be used for DGPS
- "$PMTK286,1*23" => Enable AIC (anti-inteference)
- "$PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28" => Output only RMC & GGA
- "$PMTK397,0*23" => Disable nav-speed threshold

These sentences will work to initialize other GPS-types supporting the PMTK command types.

## Usage: Get position

### Manually
This usage pattern is mostly for testing.


to get the latest fixed positions.

Pay attention to the has_fix if it is true or false. If has_fix=false, you cannot trust the other values.

### Automatically (GenEvent)
The most common usage pattern is to subscribe to the GenEvent publisher running
Check out the code inside the example-folder for an implementation for a subscriber. You need to implement (or copy) similar code to your side to receive new positions.

## Usage: simulation

### Starting manually
Start a simulated port by calling the following:

### Auto-start from config
By adding a line to config:
config :xgps, port_to_start: {:simulate,}

### Sending simulated position
Send a simulated position using one of the following commands:
XGPS.Ports_supervisor.send_simulated_position(1.1,2.2,3.3) # lat, lon, alt

## Future development
- Simulation reading from file
- Consider GenStage

## Note
This application was tested on a Raspberry Pi using the AdaFruit Ultimate GPS ([1](, [2](, which essentially uses the chip MTK3339. Guarantees for other systems and chips cannot be given. But please provide feedback if working or not on other systems/chips.