Presentation Index

 
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1

SEDRIS Spatial Reference Model

2

SRM Tutorial

3

Outline

4

Section I

5

In the Beginning ...

6

Simulation Interfaces

7

A Spectrum of Constructive, Live and Virtual Capabilities Support Training, Planning & Analysis

8

A Spectrum of Constructive, Live and Virtual Capabilities Support Training, Planning & Analysis

9

The Interface Canyons

10

Why is a Spatial Reference Model (SRM) Needed?

11

SRM Requirements

12

Location is Not Enough

13

A Shared Solution is Required!

14

Section II

15

It’s a Loooong Way Up

16

Here’s an Interesting Perspective

17

Not All Projections are Geodetic!

18

More Familiar?

19

Spatial, the Final Frontier

20

Coordinates

21

DRM <Location> (Page 15)

22

Spatial Reference Frames

23

SRF Example

24

Named SRFs in SEDRIS

25

Named SRFs in SEDRIS

26

Coordinates & Coordinate Systems

27

ERMs

28

Standard Ellipsoids

29

Standard Spheres

30

Standard Horizontal Datums

31

Standard Vertical Datums

32

ORMs

33

Many SRFs

34

Spatial Reference Model

35

Operations on Coordinates

36

Types of Operation Errors

37

Section IIB

38

Ellipsoidal Earth Reference Model (ERM) Geometry & Notation

39

Latitude, Longitude and Height for Ellipsoids & Spheres

40

Cross-Section of the Geoid, Ellipsoid and Earth Surface

41

Gravitational Field and the Geoid, Ellipsoid & Earth Surface

42

SRM Refresher

43

Section III

44

Development of Surfaces to Generate Maps

45

Map Projections

46

Projecting from 2D to 1D

47

Cylindrical Projections

48

Planar Projections

49

A Stereographic Projection

50

Conic Projections

51

Mercator Projection

52

Oblique Mercator Projection*

53

Transverse Mercator Map of the Western Hemisphere*

54

Universal Transverse Mercator (60)

55

Lines of Constant Heading*

56

Great Circle Arc between Moscow and Washington D.C.*

57

Many Map Projections are Conformal

58

Section IV

59

Augmented Projection-Based SRFs

60

“3D” Projection-based SRFs

61

Coordinate Operations affect Geometrical Relationships

62

SRF Operation Relationships

63

Geometric Distortions

64

Distance and Elevation Angle

65

Distance Distortion Can Be Mitigated, Somewhat

66

Azimuth

67

How Much Azimuth Distortion?

68

Flattening the ERM: Distance and Geometry

69

Section V

70

Modelers Often Prefer Cartesian Coordinate Frameworks

71

Non-real World 3-D Systems are often Used. Why ?

72

Relationships Between Coordinate Systems and Simulations

73

MCG&I and Dynamics Modeling

74

MCG&I

75

Dynamics Modeling

76

Section VI

77

Euclidean Distance in a Rectangular Framework

78

Defining Geometrical Concepts

79

The Traditional Surveying Process

80

Surveying is a Complex Process

81

Traditional Distance Determination in Surveys

82

Surveying on a Flat ERM

83

Surveying on a Flat ERM with a Terrain Model Added

84

Surveying on a Spherical ERM

85

Chaining on a Spherical ERM with a Terrain Model Added

86

Surveying on an Ellipsoidal ERM

87

Normal Section of an Ellipsoid

88

Distance on an Ellipsoidal ERM

89

Bearing Angles (Ellipsoidal ERM)

90

Bearing when a Point P is above the ERM Surface (Ellipsoid)

91

Once the Environment is Included, There are Many Feasible Paths

92

Placing a Solid Cube on an ERM

93

Doing the Math ...

94

Placing a Cube on the Terrain Skin Model

95

Long Linear Structures

96

Vectors in Augmented Projection-based SRFs

97

Vectors in a Curvilinear System

98

Defining a Canonical Local Tangent Plane SRF

99

A LTP Embedded in a GD SRF

100

Defining a CLTP Embedded in a GD SRF

101

Reference Vectors

102

Reference Vector Transformations

103

SRF “North” may not be True North

104

Convergence of the Meridian

105

Representing a Projection-based SRF Vector in Terms of a CLTP

106

TM series for X and Y (from P. D. Thomas)

107

Computing the Convergence of the Meridian (COM)

108

Second Method for Computing the COM

109

Computing the Sine and Cosine of the COM

110

Observations

111

Section VII

112

Why is Accuracy Needed for Coordinate Transformations?

113

Shooting at a Target in the Real World (Relative Coordinate System)

114

Simulation of Shooting at a Target (Simulation of a Relative Coordinate System)

115

Error Sources in Coordinate Transformation Software

116

Definition of Error

117

Numerical methods

118

Efficient Evaluation of Special Functions Common to Coordinate Transformations

119

Analytic (closed form) Solutions

120

Taylor/Maclaurin Series Methods

121

Iterative Methods

122

Direct Approximation of a Function or its Inverse

123

Error in Power Series Expansions

124

Authoritative Sources Sometimes Appear to Disagree

125

Error Analysis and Resolution of Disagreements

126

Effect of Small Errors

127

Fuzzy Creep/Coordinate Drift

128

Bounds Checking

129

What to Do?

130

Distortion and Computation Error Tradeoff

131

Distortion in Projection-based SRFs

132

Distortion-Accuracy Trades for UTM

133

Point Scale Equations

134

UTM Point Scale Equations

135

Linear Distortion Error For UTM

136

Difference between SR-7 & Extended Formulas for Transverse Mercator

137

Conclusions of Experiment

138

The Chaining Problem

139

Section VIII

140

SRFs

141

DRM <Location> (Page 15)

142

SRFs Supported

143

SRFs with CS Origin Offsets*

144

Local Space Rectangular

145

Local Space Rectangular (2D)

146

Geocentric

147

Geodetic

148

Geodetic (2D)

149

Local Tangent Plane

150

Local Tangent Plane (2D)

151

GCS

152

Mercator

153

Augmented Mercator

154

Oblique Mercator

155

Augm. Oblique Mercator

156

Transverse Mercator

157

Augm. Transverse Mercator

158

Universal Transverse Mercator

159

Augm. Univ. Transverse Mercator

160

Lambert Conformal Conic

161

Augm. Lambert Conformal Conic

162

Polar Stereographic

163

Augm. Polar Stereographic

164

Universal Polar Stereographic

165

Augm. Univ. Polar Stereographic

166

Equidistant Cylindrical

167

Augm. Equidistant Cylindrical

168

Geocentric Equatorial Inertial

169

Geomagnetic

170

Geocentric Solar Ecliptic

171

Geocentric Solar Magnetic

172

Solar Magnetic

173

Section IX

174

PPT Slide

175

ERM Datum Transformations

176

Init WGS84 Geoidal Separation

177

Get WGS84 Geoidal Separation

178

PPT Slide

179

Types of Operation Errors

180

“Valid” Coordinates

181

Coordinate Validity

182

Implementation Details (1 of 2)

183

Implementation Details (2 of 2)

184

Range Extension (1 of 2)

185

Range Extension (2 of 2)

186

PPT Slide

187

Op Support

188

Coordinate Operation Chains

189

Status Codes (1 of 3)

190

Status Codes (2 of 3)

191

Status Codes (3 of 3)

192

Interface Specification(s)

193

Operation Setup

194

Conversion Operation

195

Multi-conversion Operation

196

Boundary Checking

197

Operation Teardown

198

Vector Operation

199

Matrix Operation*

200

Transformation Operation

201

Convergence of Meridian Operation

202

“SRM Check Utility”*

203

Further Reading

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