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U.S. AIR FORCE AUXILIARY. ES Aircrew 2009 Update Training. US National Grid Awareness . Lt. Col. Stan Kegel Minnesota Wing. April 2009. Agenda. Our goal today: Become familiar with the US National Grid (USNG) In short, what is it?

ES Aircrew 2009 Update Training

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U.S. AIR FORCE

AUXILIARY

ES Aircrew2009 Update Training

US National Grid

Awareness

Lt. Col. Stan KegelMinnesota Wing

April 2009

- Our goal today:
- Become familiar with the US National Grid (USNG)
- In short, what is it?
- How does it relate to other common grid and coordinate systems?
- In what situations does it work well?
- Where did this requirement come from?
- Who must use it and when?
- What complications exist?

- Become familiar with the US National Grid (USNG)
- This course is only and introduction and is not intended to fully teach the ability to use USNG in navigation

- A GRID System
- Each numbered grid describes a square area (not a point like Lat/Long)
- Supports grids of many scales, from 100 km down to 1 meter (or, theoretically even smaller)
- Flat, square coordinate system
- Seamless with respect to political boundaries
- Truncated (abbreviated) form can be used often (when context tells us what part of the country is relevant)

- Based on UTM (Universal Transverse Mercator) Coordinates
- USGS topographic map “Grid North” refers to the UTM (and USNG) coordinate system

- MGRS – Military Grid Reference System
- NATO Standard

- USNG is nearly the same as MGRS
- Declared a separate standard so each can be free to change to meet the needs of its audience in the future
- Right now completely equivalent if the NAD83/WGS84 datum is used
- Differences in notation if other datums are used

- One of its benefits of the adoption of the USNG standard is that military personnel essentially already know it (and they are often acting in support of catastrophic incidents)

- UTM “zones” every 6 degrees of longitude
- Latitude band every 8 degrees of latitude
- “Grid zone designation” (GZD)
- A combination of zone andlatitude band

- Each “grid zone” has its own map projection.
- Most of Minnesota is in grid zone 15T

U

UTM/USNG Grid Zone Designations

48°N

126°

66°

96°

102°

84°

120°

108°

90°

78°

72°

114°

T

40°N

S

32°N

R

24°N

10

19

11

18

12

17

13

16

14

15

08/27/98

- A Northern Hemisphere UTM Location is given as…
- Grid Zone
- “Easting”
- Measurement (in meters) east/west of the central meridian of the zone
- The central meridian is given a value of 500,000 meters to avoid negative numbers
- Numbers greater than 500,000 are east of central meridian

- “Northing”
- Measurement (in meters) north of the equator

- Example: 15 511196 4982565 (Point on St Paul, Lake Elmo Airport)

- Grid zones broken up into “100,000 m Squares”
- Caveat: On the edges of the Grid zone, the 100,000 m squares are not square.

- Each “Square” is given a two letter “ID”
- The IDs are arranged so that the same ID occurs only a few times in the country and always a long way away
- This allows for “truncated” grid references (i.e. omitting the GZD and the 100,000 m Square ID)

- The use of 100,000 m Squares means that we don’t need the first 2 digits of the UTM Northing and the 1st digit of the UTM Easting, so these digits are omitted from USNG grid coordinates

- In full form, given as…
- Grid Zone Designation
- 100,000 m Square ID
- Easting and Northing numbers
- Always with same number of digits for each part
- The number of digits defines the grid size/precision
- Four digits:23 06 Locating a point within a 1,000-m square
- Six digits: 233 065 Locating a point within a 100-m square (football field size)
- Eight digits: 2337 0651 Locating a point within a 10-m square (modest size home)
- Ten digits: 23371 06519 Locating a point within a 1-m square (parking space size)

- Example: 15T WK 11196 82565 (Point on St Paul Lake Elmo Airport)
- Truncated form omits GZD and 100,000 m Square ID

- St Paul Lake Elmo Airport
- UTM:15 511196 4982565
- USNG:15T WK 11196 82565
- Lat/Long:44 59.78’ N 92 51.48’ W

- St Paul Downtown Airport
- UTM:15 494689 4976117
- USNG:15T VK 94689 76117
- Lat/Long:44 56.30’ N 93 04.03’ W

- For terrestrial navigation
- Not for aeronautical/maritime use

- Works best over relatively small areas
- The land can be modeled reasonably as a flat area when working in small areas

- NSARC – National SAR Committee (DOD, DHS, et. al.)
- Addressing Katrina SAR Issues:
- How do SAR Responders navigate when landmarks are destroyed
- Need for a grid system for SAR planning (resource deconfliction, etc.)

- Practical difficulties using Latitude and Longitude for terrestrial small area navigation.

- Addressing Katrina SAR Issues:

- “Catastrophic Incident” SAR
- Think Hurricane Katrina
- Think 35W Bridge Collapse

- During CIS operations, Lat/Long will be in one standard format:
DD-MM.mmm

- Land SAR Responders must use USNG; however a good familiarity with lat/long is necessary to ensure effective interface between land and air SAR responders
- Air SAR Responders will use Lat/Long

- Air space deconfliction: only in Lat/Long
- Air SAR Responders working with land SAR responders have primary responsibility of coordinating SAR using USNG
- Both need to know USNG and Lat/Long

- GARS (Global Area Reference System): used for CIS response leadership situational awareness

- Lat/Long:
- Great system for larger area navigation but…
- Distances not easy to figure out
- How far is 1 degree of longitude?
- Shorter distances get even more awkward. (How far is 0.1 minutes of longitude?)

- Difficult to accurately plot positions (or grids) based on Lat/Long with using a topo map

- Distances not easy to figure out

- Great system for larger area navigation but…
- In small areas, it is easier to think in terms of linear distances (feet, meters, kilometers, miles, etc.)
- Example: Go 100 m east, then 200 m north

- GPS devices are great for providing position info
… in a variety of possible display formats

- Lat/Long (DD MM.mmm, DD MM SS.s, …)
- UTM
- USNG
- etc.

- UTM/USNG awkward at and near grid zone boundaries