Complicated project, need help.

I want to make a locating beacon of sorts. What the beacon has to do is send out a signal to be recieved by a handheld receiver. Now that a signal is being sent out I need a reciever to pick up that signal and get its direction and or distance relative to my position. The hardest thing about this project is, it cant use a gps. I'm shure you guys have many questions, just ask. Thanks

You can't really get location or distance without multiple transmitter beacons. Even then, you would need them to be perfectly synchronized.

You could determine the direction of a beacon if you had multiple antennas on the receiver and switched through them rapidly. Do some research on "fox hunting"... it is very active in the Amateur Radio community.

Getting distance might be possible by sending a ping back and forth with a timestamp, then calculating the delay.

I'm not a expert, but what I would do is...

I would use 3 Arduinos to receive the signals on 3 receiver antennas on the same "device" all at predefined distance Ex. 30 mm. Then have a single extra device "or Arduino" do the timing to the 3 Arduinos connected to the antennas. Now when a signal comes from a beacon, you will be able to compare all times seen between all antennas and can use whatever equation you use to do a Range and bearing of the 3 antennas. If you already knew the position of the Head in GPS, you could apply the Position to the range and bearing to get a accurate GPS position with the beacon signaling.

How you do the beacon signaling is critical too, I would use a slow moving signal like sound so that the Arduinos can detect it and more accurately detect the difference on receiving antennas. The precision level of the Arduino "correct me if mistaken" is 1 nano second? Ideas ideas...

My question was going to be the medium...air or water? Etc.

Just a point. Have you got a licence to transmit at those or any other frequencies? I thought not.

Are you planning to make the transmitter yourself - your not allowed to unless you are a licensed ham and then only under strict conditions.

For an individual this project is a non starter if you want to be legal.

The precision level of the Arduino "correct me if mistaken" is 1 nano second?

Consider yourself corrected. One clock cycle at 20MHz is 50ns.

overhead of Arduino's run-time interpereter/operating system.

What does that mean? A FAIK the Arduino does not use a "run-time interpereter/operating system" just pure compiled C. And the bootloader wouldn't be a OS as it just runs at power up or reset or during uploading and does not run after that.

The simplist program I can think of:

void setup() {}
void loop() {}

Compiles to:

Binary sketch size: 448 bytes (of a 30720 byte maximum)

Not much room for a "run-time interpereter/operating system"

Maybe I just don't understand?


There are frequencies that many of us use for unlicensed transmission.

There are unlicensed bands but that doesn't mean you are allowed to construct transmitters for that band. All transmitters used in unlicensed bands must be type approved. That means the design and samples must be submitted to approved test houses for verification and qualification. I know the exact nature of this varies from country to country but I am not aware of any country that allows it's citizens to build transmitters without some form of license.

You haven't been a pilot lately, have you? VOR isn't going away any time soon. I agree, GPS is much better in many ways, but VOR technology is simply "good enough" in most cases. Good enough to guide a plane to an airport with zero visibility down to 1000ft AGL in some cases. The technology is implemented in almost every general aviation aircraft around, and most are not willing to upgrade to gps because of the lack of real benefit to GENERAL aviation pilots, and the high cost. Technology in aviation outside of commercial planes moves very slowly, and it's always the same story: too expensive, and too difficult to bring into compliance with FAA standards. The general attitude in aviation seems to be "if it's not broke, don't fix it". Similarly, you'd be surprised what kind of engines most small aircraft are powered by. I've seen lawn mowers with more advanced technology (literally). Take a look at any aeronautical map, and you'll see how firmly VOR has its foot planted in our country. And as an aside, once GPS does finally take over (we may never live to see the day), the VOR legacy will live on. Most of the airways in place now are based on and named after VORs. GPS systems as they operate currently basically act as VOR emulators. Enough of my ranting; carry on.