Pathfinding GPS waypoints with latitude and longitude of rover

[Roozki]

We will be using a Piksi V2.3.1 on the rover. We have a node that reads the Piksi and publishes the coordinates to a ROS topic (gps/fix) as a sensor_msgs::NavSatFix message. This will have a realistic accuracy of 2-4 m, should be closer to 2m when in a wide open area.

This issue is closely linked to #413,

This task will most heavily impact task 1, the traversal task: https://circ.cstag.ca/2022/tasks/
We will be awarded points for just autonomously driving to within 5m of the waypoints.
We will be given the coordinates during our setup time, so looks like we can manually enter in the waypoints.

We need to subscribe to gps/fix, find a way to read the special NavSatFix message so we can use the position of the rover to path find to the position of the next waypoint. This "pathfinding" will likely be a straight line from each waypoint, this should be fine for the first 5 waypoints, then we can switch to manual for the next 3. Our rover may not be able to traverse the last waypoints as the terrain gets technical.

I'm not sure what topic the motors subscribe to, but the end goal of this issue would be to find a path, and create a feedback loop for the rover's movement using its position. So if the rover veers off course of the next waypoint, we can use the coordinates to correct this.

Because our application is a small area, you could think of latitude and longitude as X and Y linear coordinates.
1 degree accounts for around 111.1 km, at the equator. I'm not 100% sure what the conversion is at the competition site.
Let me (Rowan) know if you have any questions, this will need a bit of brainstorming and I'm happy to hop on a call and explain it further.

For reference:

• ROS + Piksi package: http://wiki.ros.org/swiftnav_piksi
  - The above is outdated, but probably the easiest to use.
• Here is the newest version: https://github.com/ethz-asl/ethz_piksi_ros

Some random facts about GPS:

• GPS is only one positioning system, it was built by the US government. There is also GLONASS (Russia), Galileo (EU) and BeiDou (China). The umbrella term for these 4 engineering feats is GNSS (Global Navigation Satellite Systems). GNSS is pretty important in our modern world, to say the least.

• GPS is also FREE for anyone with a receiver, but it wasn't always an open resource. "GPS was built with military uses in mind during the Cold War. In 1983, Korean Air flight 007 was shot down by Soviet interceptors over Kamchatka when it went off-course. All passengers and crew aboard the civilian flight, including a sitting US congressman, were killed. Amid the ensuing controversy, President Reagan announced that GPS would be made available for free for civilian use to avoid such preventable disasters in the future. So in essence, it took the political momentum from a national tragedy for it to become freely available'

• http://en.wikipedia.org/wiki/Korean_Air_Lines_Flight_007