Pablo's Mission Planning Website

Home Links Tips Downloads MPSSF Tips

Greetings Mission Planners,

Reports of my demise have been greatly exaggerated.  After slacking off I've got quite a pile of news to get through to catch up.

PFPS 3.3.1 has entered OT (Operational Testing) and crews are traveling to Eglin AFB to test the "operational suitability" of the software - in other words they'll see if the software do what they need it to do.  So far no major problems (that I know of) have been found.  PFPS 4.0 has begun Beta testing with fielding expected next year.

Space Imaging protested when NGA awarded the second NextView contract to OrbImage a few months ago, but the General Accounting Office (GAO) has dismissed the protest.  OrbImage's planned OrbView 5 satellite will have a resolution of 41 centimeters.   Their OrbView 3 satellite in orbit today  has 1 Meter resolution and is providing data to NGA under the ClearView contract.  

NGA's signed up NuTech Solutions to do something I can't figure out.  Lots of buzzwords in their press release though.  NGA has also signed up for an Enterprise Wide license for ESRI Products:

The NGA ESA provides unlimited licenses and maintenance for the majority of ESRI products, such as ArcGIS (ArcInfo, ArcEditor, and ArcView), server products, application and extension products, and development software. During the term of the ESA, NGA has the right to deploy an unlimited number of licenses for all core ESRI products.

If you work at NGA that means you should be able to get ESRI products with a minimum of hassle. As for the rest of us - you'll have to pay up.

Most of you probably download your DAFIF and EChum from the web.  Starting next October NGA is planning to remove their products from public sale and distribution.  NGA plans to make the data available on a PKI encrypted network on the same day.  The decision has been published in the Federal Register and NGA is busy gathering feedback now.

New versions of IMOM and MESA should be released sometime in February for the Electronic Warfare minded.  There will be classes at MPUC that give introductions to the programs and teach the new features.  If you've got questions or problems you can now send them to their help desk at:

Collaboration between NSA and NGA is big news.  NGA has this news release on their website and this article was published in the LA Times earlier this month.  

The Tsunami in Asia has lead to a torrent of activity by NGA, as evidenced by this story in the Government Computer News and this news release on the NGA website.  Examples of the imagery produced by Space Imaging (with a very nice picture of Diego Garcia featuring 5 B-52's, 8 B-1's and three oil spots), Digital Globe (with some great analysis PPT presentations in pdf format), OrbImage and SPOT Image are all available on their websites.  NGA has acquired hundreds of gigabytes of Commercial Imagery in NITF format and that data is now available from their Commercial Satellite Imagery Library (CSIL).  

NGA has released the last set of SRTM DTED, as explained here.  The level 1 (3 arc second) DTED is available from the USGS here.  If you're an "Allied Nation" then it may be easier just to order from USGS than to try and go through more formal channels.  The USGS has decided to discontinue distributing the data on CD and is moving to DVD only.  Hopefully NGA will follow suit.  The image below shows the Level 1 data in of one of my favorite places - New Caledonia.  You can tell it's SRTM data immediately because it includes data voids (those black areas) where no elevation values are provided.  Not sure how they managed to get a data void in the water though...

DLA is tentatively planning a Map Catalog Training User Conference for Aberdeen Proving Ground in Maryland on March 23rd and 24th.  The conference in San Diego last summer was a great success and this should give those who didn't get a chance to go an opportunity to catch up here on the east coast.

You may remember that the World Magnetic Model (WMM) is revised every five years.  Seems like just yesterday we were waiting for WMM2000 and the SRTM Mission and now it's time for WMM2005 and we're actually getting  the SRTM data!  The WMM files are distributed on every DAFIF CD, but remain identical 99% of the time.  Normally the new WMM is distributed before the effective date, but due to a late delivery the files won't be included on the CD until the second DAFIF cycle this year - effective 16 February.  Fortunately the MPSSF has posted the new files on their website here, along with an explanation of what the WMM files are and how to update them.  

The MPSSF has also posted a great spreadsheet that explains Airspace Terms used in an ACO.  If you're like me, you've likely looked at terms like "ROZ", "MEZ", "SEMA" and "HIDACZ" and wondered what the heck they were.  This spreadsheet will really help you out.

Don't forget to register for MPUC 2005 at the MPUC Website.  MPUC is scheduled for the week of March 14th in Las Vegas and the Hotels are all packed due to other conventions that week. You need to register at the MPUC website ASAP so you can get a room at the Flamingo.  A new agenda is available as well.  

Finally, if you just can't get enough of me in these erratic Mission Planning Tips you can now read my words of wisdom in the New York Times...

Mission Planning Tip:  World Magnetic Model

For something that nobody ever pays any attention to, the WMM has managed to generate a lot of attention during this changeover.  What is the WMM?  When in doubt, read the "readme.txt" file...

The World Magnetic Models are valid for 5 years from the epoch date. WMM model and software are distributed by the National Geophysical Data Center at Boulder Colorado. A user list is maintained, and registered users will be informed of any product updates.

It is very important to note that a degree and order 12 model, such as WMM, describes only the long-wavelength spatial magnetic fluctuations due to the Earth's core. Intermediate and short-wavelength fluctuations, which originate in the Earth's mantle and crust, are not included. Consequently, isolated angular errors at various positions on the surface (primarily over land, in continental margins, and over oceanic seamounts, ridges and trenches) of several degrees may be expected. Also not included in the model are substantial fluctuations of the geomagnetic field which occur during magnetic storms.

The accuracy of a world magnetic model depends on the geomagnetic latitude. Errors are least at the equator and greatest at the magnetic poles. Globally and in ocean areas, the root-mean-square (rms) declination and inclination errors are estimated to be 1 degree or less over the 5-year life of the model. The rms errors in total intensity, horizontal intensity, and the X, Y, and Z components are estimated to be 200 nanoTeslas (nT) or less. Any questions concerning the use of this product in military systems or other magnetic data requirements should be directed to the address above.

OK, that's pretty painful to read so I'll try to break it down.  The world's magnetic field causes compass to point in a given direction at every point on the earth.  The difference between where that magnetic compass points and True North is the magnetic variation.  Unfortunately the earth's magnetic field isn't static or perfectly predictable.  That's why every airport diagram specifies both the surveyed magnetic variation and the rate of change and it also explains how a runway on a heading of 287 can still be called RWY28 - that's where it's magnetic heading started!  

The World Magnetic Model represents the main geomagnetic field that accounts for 95% of the variation, but that still leaves 5% for local variation.  The updated WMM takes into account all of those local changes, but over time the actual magnetic field will begin to deviate.  That's why the data is updated every five years.  Still, you can have inaccuracies:

On land, spatial anomalies are produced by mountain ranges, ore deposits, ground struck by lightning, geological faults, and cultural features such as trains, planes, tanks, railroad tracks, power lines, etc. The corresponding deviations are usually smaller at sea, and decrease with increasing altitude of an aircraft or spacecraft. In ocean areas, these anomalies occur most frequently along continental margins, near seamounts, and near ocean ridges, trenches, and fault zones, particularly those of volcanic origin. Ships and submarines are also sources of magnetic anomalies in the ocean.

However, from a global main field perspective, the declination (D), inclination (I), and grid variation (GV) RMS errors of WMM2005 are estimated to be less than 1.0° at the Earth’s surface over the entire 5-year life span of the model. Also, the RMS errors at the Earth’s surface horizontal intensity (H), the vertical component (Z), and the total intensity (F) of WMM2005 are estimated to be well below 200 nT over the entire 5-year life of the model. Thus, the WMM2005 meets and exceeds the accuracy requirements detailed in MIL-W-89500 (Defense Mapping Agency, 1993) for the entire life span of the model.

So what does PFPS really use the WMM data for?  Internally all PFPS data is referenced in terms of True North, but many users (especially in aviation) need magnetic headings.  As a last step PFPS converts the true headings and courses back to magnetic for display on screen or on your printout.

Now I have to let you in on a dirty little secret.  When you're in your aircraft or looking at your handheld GPS do you know where the mag heading and course values come from?  Most aircraft display headings from an Inertial Navigation Unit (INU) and most GPS's use your point to point track to determine your heading. In both cases what they know is your true heading/course.  That value is corrected using a Magnetic Model to display the magnetic heading you see.  If PFPS and your aircraft used the same Magnetic Model then the magnetic headings on your flight plan would match the ones your aircraft calculated - but it's pretty doubtful someone snuck out on the ramp and updated your aircraft's INU in the last two weeks - your aircraft may have a Magnetic Model dating from 1995.  So if your PFPS magnetic courses didn't agree with your aircraft's calculations before you updated your WMM they probably won't agree afterwards.  Still, it's better to have the most current WMM data available.

For more details see the National Geophysical Data Center (NGDC) WMM Website.