GPS integration & Way point navigation

@alba-tito

Your project seems a bit like one I started a while back, but put it on hold as my time is now taken up with a house conversion project. (and at my current rate of progress I will not get back to it for another year 🙁 ). So this will not be much help but I will give a few observations for what they are worth as your research and knowledge is probably more advanced anyway.

Firstly normal GPS is only accurate to with a few meters. This may be enough for you, but for me I wanted centimetre accuracy. This can be done (differential GPS etc) but the expense starts rise quite a lot and at this point my project was put on hold.

From two known GPS co-ordinates a compass bearing can be calculated. However for an outdoor rover robot (and I assume outdoors as GPS is no good for indoors) to be kept on track using encoders or a compass sensor etc (some sort of PID) is not really going to work assuming a variety of rough surfaces as the rover will get bounced about quite a bit (this technique is ok for smooth surfaces) and just bringing the bot back to the original bearing will mean it will probably miss the target point by quite a bit. The way to navigate the rover will be to constantly check its current GPS co-ordinates, and make a new bearing calculation for the bot to follow.

For a flying drone a few metres will not not matter much and they can fly to way points and return the the start where they then can use some sort of object recognition via its camera, like a landing circle on the ground, to make an accurate landing. You could incorporate and object recognising camera such as a Pixy2 into you design to work alongside the GPS.

To find the co-ordinates of the desired way-points you could take a reading from you GPS sensor when placed on the way-point point, or look up the GPS co-ordinates using google maps.

For Arduino to Rpi communications there are indeed a host of ways to go, but the i2c route is a good one to use for its low power requirements and if the boards are in close proximity. See the dronebots info on this where Bill is having to use i2c boosters as his boards are not so close. I would probably use the CAN bus instead instead of i2c boosters, but I would need to research this a bit more. I used serial communications for my bot that had an arduino and a Rpi, but this was just for a prototype and I will probably use i2c or a CAN bus depending on the size of my bot. Indeed the larger the bot, the bigger the battery, and the more options you will have.

OK these thoughts are just what comes to mind off the top of my head in my tea break. Good luck with your project and I would be very interested to see how you make out. Keep some project updates coming.

@byron

thank you for the advice it is very helpful.