I want to use sonar to detect obstacles. But I found the sonar I could buy in my country only could detect meters away. It's frustrating. Anyone knows if there is some advanced sonar that could detect hundreds thousands meters away? Or maybe just more than only a few meters if kilometers detecting sonar never exists. It will be better to use.
Of course it should be able to buy in the market, not the military specific ones I never have the chance to buy.
Replies
Sonar in air is extremely inefficient. Air is a very compressible medium and as such does not transfer information very well across long distances - 20 or 30 meters is really maximum for SONAR in air regardless of system.
Lidar is becoming practical and even not very expensive in the sub-100 meter category and it is considerably more focused and reliable than Sonar at any distance.
Lidar can certainly work to greater distances but you start running into very increased cost and lasers that are safety hazards.
And then there is radar, certainly an option, not a cheap or easy to implement option nor one easy to get past the FCC or equivalent in whatever country you are in.
But if you want to perceive objects beyond 30 meters, Sonar isn't even really an option (works a whole lot better in water which is an non-compressible fluid.)
Best,
Gary McCray
Then it's a radar you need, not a sonar. There are some open source radar projects, although I'm not sure it is yet light and compact enough for a small drone.
You might also want to check out LightWare for laser range finders.
Vision based obstacle detection will be the next big thing (some folks already use it)
Roben, 'sonar' is never going to be very effective at long range. Sound travels at ~330m/s A round trip to an object 330m away is going to take ~2s. Thousands of meters means a very low update frequency. In addition, sound attenuates relatively quickly in Earths atmosphere. The higher the frequency, the greater the attenuation. In order to be able to reliably detect a return signal from 1000m away you are looking at using fairly high energy. If you need to know the distance to an obstacle 1000's of meters away then I think you should be looking at some form of lasar/radar ranging.
Thanks. I had found the LIDAR on 3DR store yesterday. It's awesome thought it just make 40m. The doc said they will approach to 100m using laser the next step.
You may get the data from the sonar on your pilot board and send it to your ground station. Post it to your OSD or maybe some other stuff that can display the data. Maybe mission planner already has this feature. I haven't done research thoroughly.
You may want to check out the LIDAR Lite in the Robotics Store.
I want to mount a sonar to provide distance to object information in my OSD. Do you have any thoughts on how to provide the pilot the information (I don't need any automated obstacle avoidance capability).
Thanks/Mark
Hi Mark, I think you could hijack one of the existing params that are passed to the OSD. You would have to alter the code but it should be pretty straight forward to use the existing sonar code to read a distance and then assign the value to another parameter that you can already view on the OSD.