drone-simulator.md

Drone Simulator

The Drone Simulator is used to create a fleet of drones which send randomized location data to the UDP server.

The Drone simulator uses the following functions

1. createFleet - The createFleet function uses a set of environment variables to setup a fleet of drones.

   1. It uses the FLEET_SIZE environment variable to start a fleet of drones. It has a default value of 15.
   2. For each drone it creates a random life period between 10 and 30 seconds. At the end of this period the simulated drone shuts down and sends no further location updates
   3. It uses the UPDATE_INTERVAL environment variable to decide the interval at which the drones would send updates. It is set at a default value of 1second

2. isOnline - This function simulates the network connectivity status of the drone. This returns a promise that resolves with a Boolean specifying whether the drone is online. The function takes an argument to define the probability of the drone being online. The default probability is set at 0.5.

3. getPosition - This returns a promise that resolves with the current location of the Drone.

   The getPosition promise resolves to the following position object

   {
       latitude: '' // In Decimal Degrees
       longitude: '' // In Decimal Degrees
       timestamp: '' // Unix timestamp
   }
   

   The latitude property returns the latitude in Decimal Degrees as a String The longitude property returns the longitude in Decimal Degrees as a String The timestamp property returns the Unix timestamp as a Number

   The getPosition function takes droneId as a parameter and on subsequent calls returns the position for the drone along a tracjectory based on the drone's last position.

4. watchPosition - This function simulates the behavior of the watchPosition method of the GeoLocation API in HTML5. It takes a callback as a parameter. It then invokes the callback with a new position in a random interval of 1 to 4 seconds.