Aerowerx
Well-Known Member
Yes, I know you can just go out and buy a handheld GPS, but one with an aviation database would be $$$$.....
A comment in the DIY Gauges thread got me thinking. The comment was about having a GPS, with altitude and speed readouts, as a back up to the DIY EFIS.
My thoughts went something like this...The GPS knows where you are, so why not display your lat and long? Hmmm, if you know where you are going, calculate the distance and bearing and display it. Ok, you could punch in the lat and long of your destination, but it would be nice to just enter the airport designation, which means storing a database.
So I did some investigating... A world wide airport database is over 6 megabytes, so it would have to be trimmed down I think (but some Arduinos can use a micro SD card). It also turns out that a well equipped modern GPS receiver will do all the calculations for you! There is the NMEA sequence $GPRMB which returns the distance and bearing to a waypoint or destination. It also tells you how far off the ground track you are (distance wise) and if you need to turn left or right to get back on track.
What I have in mind is a simple text only display that gives you your current lat and long, the distance and bearing to your destination or waypoint, and your altitude and ground speed. It could also determine the ETA to your destination. If you used a touch sensitive screen you could have a virtual keyboard to enter your destination.
I think the hardest part would be sorting through the database. If you wanted a "Nearest" function then you would have to go through the database and calculate the distance to all the airports and pick the closest (or, with some clever programming, keep track of the closest in real time).
I have not "officially" checked the prices on this, but from what I have seen it could be built for around $150 to $200 (US $).
Comments?
A comment in the DIY Gauges thread got me thinking. The comment was about having a GPS, with altitude and speed readouts, as a back up to the DIY EFIS.
My thoughts went something like this...The GPS knows where you are, so why not display your lat and long? Hmmm, if you know where you are going, calculate the distance and bearing and display it. Ok, you could punch in the lat and long of your destination, but it would be nice to just enter the airport designation, which means storing a database.
So I did some investigating... A world wide airport database is over 6 megabytes, so it would have to be trimmed down I think (but some Arduinos can use a micro SD card). It also turns out that a well equipped modern GPS receiver will do all the calculations for you! There is the NMEA sequence $GPRMB which returns the distance and bearing to a waypoint or destination. It also tells you how far off the ground track you are (distance wise) and if you need to turn left or right to get back on track.
What I have in mind is a simple text only display that gives you your current lat and long, the distance and bearing to your destination or waypoint, and your altitude and ground speed. It could also determine the ETA to your destination. If you used a touch sensitive screen you could have a virtual keyboard to enter your destination.
I think the hardest part would be sorting through the database. If you wanted a "Nearest" function then you would have to go through the database and calculate the distance to all the airports and pick the closest (or, with some clever programming, keep track of the closest in real time).
I have not "officially" checked the prices on this, but from what I have seen it could be built for around $150 to $200 (US $).
Comments?
