Using Multilateration - MLAT Option 1 - Ground Station - data provider and data user Option 2 - Master User - downloader only Problems with MLAT? Where do I get the updated FTD2 dll software?

Using Multilateration - MLAT

This information was kindly supplied by Tim Plumridge - see this Yahoo group message - many thanks, Tim.

For full details of exactly how MLAT works read the Multilateration tutorial found by doing a search in the Help section of Plane Plotter (PP).  There follows a summary of the basics required in setting it up, which should be read in conjunction with the tutorial.  There are 2 options as to how to use MLAT:-

1.    Become a Ground Station and get Master User MLat for free.

2.    Obtain a 21 day MLat trial after which you can pay €12 to continue using it as a Master user.

Option 1 - Ground Station - data provider and data user

This option requires you to be able to provide “raw data” on a regular basis (ideally 24/7) but for many users this is simply not possible or practical so as long as data is provided for reasonable amounts of time this is generally OK.  Obviously the more Ground Stations there are up and running the better for the general PP community, especially in areas of limited coverage, as MLAT requires at least 3 Ground Stations (ideally more) to be successful.

To become a Ground Station you need to be running SBS-1 (or -1E etc) as unfortunately the data from RadarBox cannot be processed.

To get started, then ...

1. Ensure the PC / laptop clock is accurate and maintained so.  A good (free) program that does this and runs in the background can be downloaded from http://www.meinberg.de/english/sw/ntp.htm

    

2. Ensure the Home location is accurate.  Be sure to use the Test facility on Options, Home location to verify this.

    

3. For SBS via USB

   i.    Ensure both Base Station and PP are both closed.

   ii.    Locate the file FTD2XX.DLL (Located either in the Base Station directory or more usually C:\Windows\System32) and rename it to FTD2XX.DLL.backup.

   iii.    Visit http://mode-s.66ghz.com/vodka.zip and when unzipped copy the 2 files FTD2XX.DLL and FTD2XX1.DLL to the Base Station directory. (These are collectively referred to as the “Vodka patch.”).  Please note that sometimes this link does not work as expected - simply cut the text:  http://mode-s.66ghz.com/vodka.zip  and paste it into the address bar of your Web browser.

   iv.    Start Base Station and confirm it is working properly.

   v.    Open PP and under Options, I/O settings ensure the SBS raw data box is ticked with 9742 in the UDP/IP local port box.

   vi.    Start to run PP

    

4. For SBS via Ethernet - please follow Section 3.2 in the MLAT tutorial.

    

5. With PP and Base Station both up and running, send a message to the group under the header MLAT: asking to be approved as a Ground Station. Be sure to quote your two-character share code as well - you can get this from Help, About - it's the two characters after the {registraion number}.

    

6. Assuming you are approved, the fun starts now with setting up the router!  A good idea is to study the PlanePlotter data Flow PDF file in the PP Yahoo group’s Files section to get an idea of the flow of data for MLAT and how it compares with that for “ordinary” data.  There is such a plethora of different routers, but as a first port of call look in the group’s Files section to see if your specific model is covered.  If not, try www.portforward.com as that gives basic details as to how to forward ports for a wide range of different routers, albeit not specifically for MLAT.

    

7. To access your router, and get it to forward the raw data to the appropriate PC / laptop, run a Command prompt and type in IPCONFIG (Accessed either by Start, All programs, Accessories, Command prompt OR Windows button and R simultaneously and then type CMD and Enter.  Amongst the information returned (maybe it needs scrolling up) will be your computer’s IP as well as the router’s IP (sometimes “Default Gateway”), both in the form 192.168.*.*

    

8. Type the Router’s IP address in your address bar and Enter; you will then get details on your router.

    

9. If you are lucky in that your router’s details are covered in the Files section, great; follow the instructions there.  Otherwise get a clue from www.portforward.com by selecting your model, clicking through the ad on the next page and clicking Default guide near the top of the page.  Generally, look for something similar to Virtual Servers or Application sharing.  (It may need going to an “Advanced settings” option. In any case to access most router’s settings requires a password; by default the Username is usually admin or blank and the password left blank.)  The port number required is 9742 (or range 9742 – 9742), the protocol UDP (not TCP) and the LAN address should be that specific to the PC / laptop as found earlier from IPCONFIG. Finally name it something relevant, and apply or enable the changes.  Sometimes the router loses the assignation to the chosen computer, especially after it doing an upgrade; it can be changed as above.

    

10. Not always specifically required, but it MAY help to reboot the router and computer if MLAT doesn’t work.

     

11. Depending on the router, other options including Denial of service (DOS) may need to be considered, as well as making adjustments to some firewalls if not using the default Windows one.  At this stage, if MLAT is unsuccessful, a request to the group may get results.

     

12. Now is the time to try MLAT! In the Aircraft list, initially look for an entry in green with no positional information (preferably high level), hold control and left click; the MLAT box should appear.

     

13. As the cycle continues, the number of raw data reports received should increase until just over 60 seconds when, if successful, the approximate position of your selected aircraft will appear on screen, at which stage an automatic 2nd cycle starts.

     

14. A contrail can be added to the chosen aircraft as it is MLATed by right clicking it and selecting Contrail.

     

15. MLAT will continue on a particular aircraft at 30 second intervals after each 60+ second cycle until such time as there are insufficient raw data reports or the user stops the cycle.  To stop it, ensure the top right cross in the MLAT box is red and hit the Esc key;  a final positional fix may be given if it had run for long enough before being stopped.  To ensure it does not continue, either MLAT a different aircraft or left click any aircraft in the Aircraft list.

     

16. At any time to check the MLAT status, run the PPuser.exe file from the group’s Files section.
17. Various problems associated with MLAT can be seen in MLAT troubleshooting.

Option 2 - Master User - downloader only

If for any reason you are unable to meet the criteria of becoming a Ground Station e.g. you are a RadarBox user, don’t have SBS or are simply unable to leave the computer on for long periods of time, then paying is the only option.  Visit http://www.coaa.co.uk/mlat_request.php and continue clicking through to complete the process; this gives a 21 day trial after which you can chose to pay the €12 if you wish.  Having done this, follow the above from Step 5.

Problems with MLAT?

Check out the MLAT Troubleshooting Guide

Where do I get the updated FTD2 dll software?

Get this file: http://mode-s.66ghz.com/vodka.zip (you may need to copy and paste that URL) and if you still have problems, try asking in the Plane Plotter Yahoo group for the file vodka.zip.