taken with 7mgp camera and own design foamy
marymoor rc park
sweet uav !!
taken with 7mgp camera and own design foamy
marymoor rc park
sweet uav !!
I have bought a Pentax Optio A30 to use as my aerial camera. It is similar to a number of the latest generation of sub-compact 10Mpixel cameras and has good reviews, especially in terms of its image quality. It weighs about 160gm with battery and SD memory card and at 58mm,has one of the smallest widths I have found – important for fittinginto the Cularis body.
The highest resolution image is quoted as 3648 x 2736 pixels. Based on the handbook, a 4Gbyte SD memory card at the best quality jpeg setting, should give about 1200 images. The camera has a continuous mode where images are taken and downloaded to the SD card as fast as possible as long as the shutteris pressed. One option for using the camera in the UAV, is to set itrunning in continuous mode and then select 1 in n of the imagesproduced to make the photo-composite.
With a fully charged battery, I tested the camera in continuous mode while photographing a clock. The camera managed to capture 1613 images at full resolution in high quality mode in 23 minutes before filling the 4Gbyte SD card. The battery indicator showed about half full at the end of the run.Although the average interval was about 1.2 seconds, there were somegaps between images of up to 8 seconds and in other cases, 2sequential images showed the same time. Both results suggest thatthe timing is not constant, but is a function of the amount of datathat needs to be stored on the card. The review also states that thefile size varies a lot depending upon the image content, so this makematters worse.
I then tried taking photos at timed intervals. I could get down to about a 4 second interval with only an occasional missed image, although this may have been finger trouble. So if I want images taken at regular, known intervals, I will have to use a servo driven IR interface such as the PRISM.
Now to look at flying the camera. There are two limiting scenarios.
Comments and Questions.
Surprisingly, Atkins adds that during takeoff, the UAV is blind. “The plane takes no measurements of its surroundings. The waves would confuse it. ‘Most people wouldn’t do it this way,’ Atkins said. ‘The plane puts the motors on at full throttle and sets the pitch elevator enough to break out of the water. Then it counts and pitches forward. We believe that if we had done it any other way, we would have basically dived into the ocean on takeoff because the plane would have detected huge oscillations due to the waves.’”
And here's an interesting observation from the project's home page:NASA is developing a navigation system that augments GPS signals via a satellite phone network so that it works around the globe, beyond the limited implementation of WAAS. Their intended application is a UAV based mapping function utilizing synthetic aperture radar technology which requires a highly stable and accurate platform.
For testing purposes they will mount the radar and navigation system on a Gulfstream III (I especially like this part), "Since the Gulfstream III operates outside civilian air space it will not need a permit to use the UAV which takes 90-days due to a somewhat archaic processing system." I guess we're not the only ones frustrated with the FAA, even the best & brightest at NASA have a hard time with the red tape!
For details see article:
Nasa Develops Highly Accurate Plane Nav System
The PPA system will help keep the C-20A Gulfstream III flying level so the UAVSAR radar pod can scan geoseismic hot spots.
[UPDATED: paper is finished and available below]
I've put together a technical assessment white paper for the FIRST robotics league, proposing an indoor aerial robotics contest for 12-17 year old kids (and coaches). Target price is under $1,000 and safety is of prime importance. This paper lists the possible platforms--microplanes, helis, quadcopters and blimps--and discusses the pros and cons of each. At this point I've tried most of the options, from helicopters to quadrotors to blimps to ultralight planes and I'm leaning towards quadcopters and blimps as the best choice.
Cost, simplicity and safety pushed me towards the blimps, but I'm concerned about having the kids having to build the autopilot from scratch. Check out the draft of my white paper and tell me what you think.
This post describes the beta version of BASIC Stamp autopilot code. As mentioned in my last post, the two main challenges in this project were dealing with the constraints of integer-only math and a severely restricted variable space (just 26 bytes!).
The first one I got around by treating fractional degrees as full degrees (since the UAV is never going to travel more than one full degree away from launch) and essentially treating them as integers. This was a little tricky, since I'm limited to word-length variables (with a max value of 65,535, which is essentially 4 and half digits of precision) and the GPS natively generates six and half digits of precision (360.9999 W/E). But I truncated the full degrees to just 1 and -1 from the current position, and that let me retain the full precision of the fractional degrees.
The second problem I got around by splitting the program up into five sub-programs (each one is allowed to reuse the variable space in RAM) and switching in real-time between them. I also used the Stamp chip's 121 bytes of "scratchpad" memory to store a lookup table of all the waypoints, and that's available to all the programs, although you can't manipulate the scratchpad memory directly without copying it into a variable.
The current program does three things:
The code has been tested on several different kinds of servo driver chips and GPS modules, as well as with GPS simulators, but not yet in the air. So consider it just instructional at this point. I'm sure there are some bugs, and a lot of settings that need to be tweaked. Also, we have not yet added camera controls and other more sophisticated in-air options, such as circle and hold (although these aren't hard to add, not that we've got the basic hardware interfaces working).
You can download the code at the following link. Load the first program (uav.bsp) and it will call the others at compile and download time.
The recommended hardware is a Basic Stamp BS2p on a dev board using the FT639 servo driver chip and a standard GPS module such as the EM406. Details on these hardware configurations can be found in the main post on this UAV. Other servo drivers, such as the Parallax board can be used, and the details on how to modify the code for them is in the comments of the code
We love GoogleMaps, but one of the problems with it is that you can't really add your own data to it. Sure, you can superimpose your imagery on a GoogleMaps layer, but it won't show unless people use a special URL. That's the reason for the creation of OpenAerialMap.
Pict'Earth's Jeff Johnson explains:
"OAM gives us a place to publish the imagery so that it easily reused. Basically the imagery that Google and MS Aggregate is not truly 'free' in the sense that it cannot be used in any useful sense outside of their programs without an overbearing license. Its kind of like Navteq or Teleatlas data. It may be freely available, but its not really free. So then, the goal of OAM is to provide a place where people like us (doing DIY stuff) can publish our imagery in a central place, but also a place for governments and other organizations that pay for imagery to get help publishing their data into the public space in an open/free way."
O'Reilly's Brady Forrest has great post that explans more here. (He also mentioned that I'm going to be giving a DIYDrones presentation at ETech on March 3-4 in San Diego. More on that later.)
You can see one example of one pass I took of the Alameda Naval Air Station runway that was orthrectified and stitched by Pict'Earth and is now part of the standard OAM map at that lat-lon (our imagery circled in the screen shot above).
(credits: Christopher Schmidt set up OpenAerialMap and the servers are hosted by Telascience, SDSC and bandwidth comes from CalIT)