+ Reply to Thread
Page 1 of 2 12 LastLast
Results 1 to 15 of 28

Thread: Build a simple radar altimeter

  1. #1
    Registered User
    Join Date
    Apr 2011
    Location
    CT
    Posts
    13

    Build a simple radar altimeter

    Have anyone tried to build this radar altimeter: S53MV ARM DSP Vertical Navigation Radar

    Or anyone that have experience in building electronics that can direct me to either where I should buy the components or a good forum for building electronics?

    Thanks,
    Chris

  2. #2
    Registered User
    Join Date
    Dec 2008
    Location
    WI
    Posts
    142

    Re: Build a simple radar altimeter


  3. #3
    Moderator Dana's Avatar
    Join Date
    Apr 2007
    Posts
    5,359

    Re: Build a simple radar altimeter

    That's pretty cool. But it's sure not a beginner project! I've built quite a few electronic projects and I wouldn't attempt this one.

    Chris, where in CT are you?

    -Dana

    The first rule of intelligent tinkering is to save all the parts.
    Fisher FP-404
    ParaFan PPG
    Kolb Ultrastar

  4. #4
    Registered User
    Join Date
    Apr 2011
    Location
    CT
    Posts
    13

    Re: Build a simple radar altimeter

    jhausch: Thanks, I'll check out that forum!

    Dana: I'm in Westbrook, you?

  5. #5
    Registered User djschwartz's Avatar
    Join Date
    Jun 2008
    Location
    Portland, Oregon
    Posts
    955

    Re: Build a simple radar altimeter

    This device would be illegal to operate in the US. A radio transmitter such as this requires type acceptance by the FCC. The FCC is independent of the FAA and doesn't care whether or not the device is in a homebuilt or certified aircraft. FCC type acceptance is a formal process that must be done by a certified laboratory that can verify that the transmitted signal is within the legal limits for the given band of operation and that the device meets all requirements for not causing interference to other radio services. Doing this would cost far more than just buying a radio altimeter.

    The only exception to this would be if the device is operated in one of the Amateur Radio frequency bands, and then you would need an appropriate class of Amateur Radio License to operate it.

  6. #6
    Registered User
    Join Date
    Jan 2011
    Location
    Southern Ohio
    Posts
    1,217

    Re: Build a simple radar altimeter

    I'm not sure of your application, but it's hard to see the utility of a project like this, unless it's just "for the halibut."
    -- "Real IFR" use (for backup in determining when you'd reached MDA, etc): You'd want something that was 100% bulletproof and reliable. A homebrew radar altimeter probably doesn't qualify. In addition to possibly interfering with equipment on other aircraft (and the FCC will want to know all about this, as djschwartz mentioned), you'd need to assure all the equipment used in a typical airport environment wouldn't give false readings on your device. That's not an easy job.

    -- "How high are we" general info when not in IMC: A laser rangefinder would give you the same information but without all the frequency deconfliction/interference worries. You'd still need to check on the legalities and problems of pointing a low-power laser at the ground while in flight, but it would seem less dangerous than the RF approach.
    -- For terrain avoidance in general: A good GPS with terrain depiction will be cheaper (esp if you place a dollar value on your time) and far more effective at helping a pilot avoid terrain. A radar altimeter obviously tells you nothing about your height above the terrain you'll be overflying in 20 seconds, it's just a snapshot of the present.

  7. #7
    Registered User cluttonfred's Avatar
    Join Date
    Feb 2010
    Location
    Nairobi, Kenya
    Posts
    1,463

    Re: Build a simple radar altimeter

    I am no expert, but perhaps an alternative to this might be some sort of laser rangefinder? I have seen some projects online using a hacked webcam. You might also be able to adapt a laser measuring tape used in construction for the same purpose.

    For short range use, perhaps just to guide the landing flare in an aircraft with poor visibility, you could use an ultrasonic sensor, like the old Polaroid cameras or the "b beep, beep" parking sensors in car bumpers. Range would only be a few meters, but that's enough for that application, more of a "ground warning indicator" than an altimeter.
    *******
    Matthew Long, Editor
    cluttonfred.info
    A site for builders, owners and fans of Eric Clutton's FRED

    Voici ce que j'ai fait...vous pouvez en faire autant!
    "This is what I have done...you can do the same!"
    --Henri Mignet (1893-1965)

  8. #8
    Registered User
    Join Date
    Apr 2011
    Location
    CT
    Posts
    13

    Re: Build a simple radar altimeter

    The intention is to use as a secondary help for float plane (experimental) landing on glassy water. But maybe a laser range finder or a ultrasonic sensor makes more sense. Are there any laser range finders or ultrasonic sensors for aircraft applications, or that can be adopted to put on an aircraft?

  9. #9
    Registered User Empirical's Avatar
    Join Date
    Oct 2010
    Location
    Greece
    Posts
    164

    Re: Build a simple radar altimeter

    First of all this is NOT a "simple" device construction-wise or even design-wise. Perhaps it is less complicated compared to other types, but definitely NOT a "simple" one.

    You'll need to have a lot of experience in building electronics, especially in RF circuits (which includes soldering and machining experience and making shields with copper/brass) and aluminium, etc). You should be able to make perfect solders of any type, and handle connectors, RF-cables, SMD and other sensitive components without destroying them or damaging them from the soldering heat, or short-circuit the PCB. Even the remnants of solder flux can affect the performance, or worse, suddenly block the device after some years of normal operation! (PCBs should always be cleansed with alcohol). The whole device including the connectors should also be protected from moisture.

    You'll also need the necessary tools for the task including a high quality temperature-controlled soldering iron with special tips for SMD, the necessary microcontroller programmers (one for LPC2148 and one for the PIC16F876A), a magnifying lens, a multimeter etc. You might also need some instruments in order to calibrate the frequency range of VCO, etc. For that, the device should have a calibrating mode.

    BTW, a parts list is missing(!), you might have to ask the webpage owner.


    In sort, (since you are a beginner), to avoid all kinds of problems, it's far better to order one from the author -except if your priority is to gain some experience & knowledge in electronics at any (time & money) cost -NOT to have a radar altimeter in your aircraft.
    A wonderful harmony arises from joining together the seemingly unconnected.
    - Heraclitus (Greek Philosopher 535-475 B.C )

  10. #10
    Registered User
    Join Date
    Apr 2011
    Location
    CT
    Posts
    13

    Re: Build a simple radar altimeter

    I've actually been in contact with the webpage owner, and asked for a part list, but he didn't have one. My idea was to get some experience as well use it later on, but I don't want it to be a year long project, rather a few months at max. Maybe you're right, it's too big project.

    Anyone experience with this: Roke | Miniature Radar Altimeters ?

  11. #11
    Moderator Topaz's Avatar
    Join Date
    Jul 2005
    Location
    Orange County, California
    Posts
    8,834

    Re: Build a simple radar altimeter

    Quote Originally Posted by XAviator View Post
    The intention is to use as a secondary help for float plane (experimental) landing on glassy water. But maybe a laser range finder or a ultrasonic sensor makes more sense. Are there any laser range finders or ultrasonic sensors for aircraft applications, or that can be adopted to put on an aircraft?
    Luxury cars and SUVs are sprouting ultrasonic range sensors all over their back bumpers these days. They're intended for keeping the driver from backing into a car or other object. Might be a place to get started. I don't know how useful laser would be on water, pointing vertically at the surface. I would think you'd get a lot of loss to the reflected signal.
    "If you have built castles in the air, your work need not be lost; that is where they should be. Now put the foundations under them." - Henry James Thoreau

    Design Project: Conceptual Design of an "Inexpensive" Single-Seat Motorglider
    Discussion Thread for the Project: Discussion: Conceptual Design of an "Inexpensive" Single-Seat Motorglider

  12. #12
    Moderator Dana's Avatar
    Join Date
    Apr 2007
    Posts
    5,359

    Re: Build a simple radar altimeter

    Quote Originally Posted by Matthew View Post
    For short range use, perhaps just to guide the landing flare in an aircraft with poor visibility, you could use an ultrasonic sensor, like the old Polaroid cameras or the "b beep, beep" parking sensors in car bumpers. Range would only be a few meters, but that's enough for that application, more of a "ground warning indicator" than an altimeter.
    The previous owner of my plane had trouble judging his landing flare, so he installed just such a system... it was sold as a parking aid, with red, yellow, and green lights for people who couldn't manage to stop their car in time to keep from going through their garage wall. It had the Polaroid sonic transducer (which Polaroid sells to other manufacturers). I don't know how well it worked; he said the lights were difficult to see in bright daylight.

    XAviator, I sent you a PM.

    -Dana

    "The world that we have made as a result of the level of thinking we have done this far creates problems we cannot solve at the same level of thinking at which we created them." -- Albert Einstein
    Fisher FP-404
    ParaFan PPG
    Kolb Ultrastar

  13. #13
    Registered User
    Join Date
    Dec 2008
    Location
    WI
    Posts
    142

    Re: Build a simple radar altimeter

    I would think an ultrasonic solution would have issue perpendicularity, but, more so, with the wind. I sell ultrasonic sensors for the industrial/automation market and I don't know how reliable one would be trying to get a signal from a target moving at 40-60mph relative to the sensor - along with the fact that the sensor is moving as is the column of air through which it is trying to sense. This is just a guess on my part, but it would be my first concern.

  14. #14
    Registered User Kristoffon's Avatar
    Join Date
    Sep 2009
    Location
    Brazil
    Posts
    349

    Re: Build a simple radar altimeter

    As someone who designs electronic circuits for a living, assuming the circuit posted does work as advertised, I find it extremely unlikely that anybody without good experience working with HF electronics will be able to get this working due to all the little gotchas that you just have to know about, and lots of expensive test equipment to nail them.

    Ultrasonic would probably be the way to go. There are waterproof transducers, the circuit is simple and easy, there are probably working ones on the interne that will give a numerical readout.
    Building: Osprey-II

  15. #15
    Registered User
    Join Date
    Apr 2011
    Location
    CT
    Posts
    13

    Re: Build a simple radar altimeter

    OK, I've officially given up the idea of making that radar altimeter. It seems like ultrasonic or laser is a better and simpler solution. Unless Roke | Miniature Radar Altimeters will quote me a good price for their radar altimeter. I would have liked to get some experience in making electronics, but I guess that will be for another day.

    I wonder how laser or ultrasonic respond to, not just to 40-60mph relative to ground, but also choppy or wavy water? (It will be used on glassy water, but I don't want it to give false signals when in other conditions)

+ Reply to Thread
Page 1 of 2 12 LastLast

Similar Threads

  1. ATC changing from radar to GPS?
    By Titanium Cranium in forum Hangar Flying
    Replies: 3
    Last Post: February 19th, 2011, 07:47 AM
  2. [Wanted] WTB Altimeter
    By newflyer in forum For Sale / Wanted
    Replies: 1
    Last Post: November 6th, 2010, 12:47 PM
  3. Encoding altimeter to transponder
    By Offcenter in forum Instruments / Avionics / Electrical System
    Replies: 6
    Last Post: September 6th, 2009, 05:36 PM
  4. altimeter ?
    By jany77 in forum Instruments / Avionics / Electrical System
    Replies: 3
    Last Post: May 6th, 2007, 08:15 PM
  5. Radar/Lazer altitude indicator
    By craftsven in forum Aircraft Design / Aerodynamics / New Technology
    Replies: 14
    Last Post: January 17th, 2007, 02:53 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts