The document discusses methods for determining the geoid, the figure of the Earth approximating mean sea level. It defines the geoid and explains that it can be determined through gravimetric and satellite methods. Specifically, it describes using Stokes' integral formula with gravity anomaly data to calculate geoid undulations, and how the modern GRACE satellites directly measure tiny changes in the Earth's gravity field to map the geoid every 30 days. The document provides details on measuring gravity anomalies, topographic reductions, and applications of determining the accurate geoid, such as for construction projects and resolving height controversies.
This document discusses the concept of isostasy, which refers to the equilibrium between the continental and oceanic crust due to gravitational forces. It was first defined in 1889 by American geologist Clarence Dutton. The main points are that the continental crust must be composed of lighter materials than the ocean floor to remain in equilibrium. Also, wherever the continental crust is thinner under the oceans, it extends below the ocean floor to maintain equilibrium. Early evidence for isostasy came from Pierre Bouguer's 1735 expedition to the Andes mountains, where he observed smaller than expected gravitational attraction that indicated compensation of the mountains' mass.
Gravity and magnetic methods are an essential part of oil exploration. They do not replace seismic. Rather, they add to it. Despite being comparatively low-resolution, they have some very big advantages.
These geophysical methods passively measure natural variations in the earth’s gravity and magnetic fields over a map area and then try to relate these variations to geologic features in the subsurface. Lacking a controlled source, such surveys are usually environmentally unobjectionable.
This document discusses the different types of aerial cameras used for photogrammetry. It describes single-lens frame cameras which have a fixed lens and film and are classified by their angular field of view. It also covers multi-lens frame cameras which use two or more lenses to simultaneously expose the same area on different films. Strip cameras are described as using a single or two lenses to continuously photograph a film passing over a narrow slit. Finally, panoramic cameras are outlined as providing a horizontal strip of terrain from horizon to horizon by laterally scanning from one side to the other.
The document discusses coordinate systems used in geodesy. It describes how a point on Earth's surface is projected onto a reference spheroid and geoid to define its horizontal and vertical positions. Geodetic coordinates use latitude, longitude, and elevation to precisely locate points on the spheroid. It also describes the Cartesian coordinate system and WGS 84 system used by the U.S. Defense Department as a geocentric reference frame. Key elements like great circles, parallels, and meridians are defined on the spheroid for determining latitude and longitude.
Distortions and displacement on aerial photographchandan00781
This document discusses various types of distortions that can occur in aerial photographs. It defines distortion as a shift in the position of landscape features that alters the perspective of the image. Displacement is defined as any shift that does not change the perspective. The document outlines different types of distortions including lens distortion, relief displacement caused by elevation differences, and tilt distortions from aircraft motion like roll, crab, and pitch. It also discusses parallax, orthorectification to remove distortions, and parameters that influence relief displacement.
This document discusses methods for calculating the heights of objects like trees and buildings from aerial photos. It describes the relief/radial displacement method, where the displacement between the top and bottom of an object seen in a single aerial photo is used along with the distance from the principal point to determine height. It explains that relief displacement occurs due to perspective projection and varies with object elevation relative to the datum. An example problem demonstrates using measured displacement and distance to calculate an object's height given the flying height.
Location. Location. Location. With so many maps and datums out there, how does a person know what datum is correct? How come my GPS coordinates don\'t match up on my map? Why is there a shift of 100 metres? How do I transform between different datums? What is a datum? What is the EPSG? Why have GIS Vendors and Oracle adopted them? Does offshore or onshore make a difference? How come there are so many datums? This presentation looks to provide some answers to some of these questions and to point out that latitude and longitude are not absolute.
Over the decades that surveyors have been trying to map the Earth, history and politics have shaped the way we see the world. Are the borders actually there? What if one nation adopts a standard, but the other does not? Does really matter what the co-ordinate system is? Why when I draw the a UTM Projection, the lines are curved, not in a grid? Is the OGC adopting these standards? So many questions and this presentation aims to answer some of them and provide some light on a complicated and sometimes unclear topic.
The document discusses methods for determining the geoid, the figure of the Earth approximating mean sea level. It defines the geoid and explains that it can be determined through gravimetric and satellite methods. Specifically, it describes using Stokes' integral formula with gravity anomaly data to calculate geoid undulations, and how the modern GRACE satellites directly measure tiny changes in the Earth's gravity field to map the geoid every 30 days. The document provides details on measuring gravity anomalies, topographic reductions, and applications of determining the accurate geoid, such as for construction projects and resolving height controversies.
This document discusses the concept of isostasy, which refers to the equilibrium between the continental and oceanic crust due to gravitational forces. It was first defined in 1889 by American geologist Clarence Dutton. The main points are that the continental crust must be composed of lighter materials than the ocean floor to remain in equilibrium. Also, wherever the continental crust is thinner under the oceans, it extends below the ocean floor to maintain equilibrium. Early evidence for isostasy came from Pierre Bouguer's 1735 expedition to the Andes mountains, where he observed smaller than expected gravitational attraction that indicated compensation of the mountains' mass.
Gravity and magnetic methods are an essential part of oil exploration. They do not replace seismic. Rather, they add to it. Despite being comparatively low-resolution, they have some very big advantages.
These geophysical methods passively measure natural variations in the earth’s gravity and magnetic fields over a map area and then try to relate these variations to geologic features in the subsurface. Lacking a controlled source, such surveys are usually environmentally unobjectionable.
This document discusses the different types of aerial cameras used for photogrammetry. It describes single-lens frame cameras which have a fixed lens and film and are classified by their angular field of view. It also covers multi-lens frame cameras which use two or more lenses to simultaneously expose the same area on different films. Strip cameras are described as using a single or two lenses to continuously photograph a film passing over a narrow slit. Finally, panoramic cameras are outlined as providing a horizontal strip of terrain from horizon to horizon by laterally scanning from one side to the other.
The document discusses coordinate systems used in geodesy. It describes how a point on Earth's surface is projected onto a reference spheroid and geoid to define its horizontal and vertical positions. Geodetic coordinates use latitude, longitude, and elevation to precisely locate points on the spheroid. It also describes the Cartesian coordinate system and WGS 84 system used by the U.S. Defense Department as a geocentric reference frame. Key elements like great circles, parallels, and meridians are defined on the spheroid for determining latitude and longitude.
Distortions and displacement on aerial photographchandan00781
This document discusses various types of distortions that can occur in aerial photographs. It defines distortion as a shift in the position of landscape features that alters the perspective of the image. Displacement is defined as any shift that does not change the perspective. The document outlines different types of distortions including lens distortion, relief displacement caused by elevation differences, and tilt distortions from aircraft motion like roll, crab, and pitch. It also discusses parallax, orthorectification to remove distortions, and parameters that influence relief displacement.
This document discusses methods for calculating the heights of objects like trees and buildings from aerial photos. It describes the relief/radial displacement method, where the displacement between the top and bottom of an object seen in a single aerial photo is used along with the distance from the principal point to determine height. It explains that relief displacement occurs due to perspective projection and varies with object elevation relative to the datum. An example problem demonstrates using measured displacement and distance to calculate an object's height given the flying height.
Location. Location. Location. With so many maps and datums out there, how does a person know what datum is correct? How come my GPS coordinates don\'t match up on my map? Why is there a shift of 100 metres? How do I transform between different datums? What is a datum? What is the EPSG? Why have GIS Vendors and Oracle adopted them? Does offshore or onshore make a difference? How come there are so many datums? This presentation looks to provide some answers to some of these questions and to point out that latitude and longitude are not absolute.
Over the decades that surveyors have been trying to map the Earth, history and politics have shaped the way we see the world. Are the borders actually there? What if one nation adopts a standard, but the other does not? Does really matter what the co-ordinate system is? Why when I draw the a UTM Projection, the lines are curved, not in a grid? Is the OGC adopting these standards? So many questions and this presentation aims to answer some of them and provide some light on a complicated and sometimes unclear topic.
This document discusses different coordinate systems used to define locations on Earth. It describes the Everest spheroid, which defines India's geodetic datum. It then explains geographic and geocentric coordinate systems. The geographic system uses latitude and longitude based on a spherical model of Earth. The geocentric system assigns each point an (x,y,z) coordinate using a Cartesian grid with origins at Earth's center. The document provides formulas to convert between the two systems.
This document discusses stereoscopy and parallax measurement in aerial photography. Stereoscopy uses two photographs of the same ground area taken from separate positions to create a stereo pair that enables three-dimensional viewing. Parallax is the displacement of an object caused by a change in the point of observation. Stereoscopic parallax occurs when photographs are taken of the same object from different positions, allowing measurement of differences in elevation.
This document discusses various techniques for analyzing aerial photographs, including:
- Calculating the scale of photographs based on known distances and camera specifications. Scale expresses the ratio of distances on the photo to distances on the ground.
- Determining the heights of objects visible in photos using relief displacement, which measures the difference in an object's appearance between the top and bottom due to perspective.
- Planning flight paths to ensure adequate overlap between consecutive aerial photos for stereoscopic analysis and 3D modeling.
- Using a stereoscope to merge overlapping photo pairs and perceive depth and parallax differences between matching points in the stereo pair.
Geodesy - Definition, Types, Uses and ApplicationsAhmed Nassar
literature review speaks about the geodesy and its relation to the figure of the earth. The definition of geodesy and the imagining of the earth's shape evolution throughout history, it passed at many important developments. We will discuss that geodesy almost interferes with all Geo- and Space sciences, by clarifying some of its uses and applications.
Aerial photographs and their interpretationSumant Diwakar
Aerial photographs provide valuable information about the coastal and terrestrial environment when interpreted correctly. Vertical aerial photographs can be used to update existing maps and create new maps. Simple instruments can be used to correct horizontal distortion in aerial photographs and transfer information to line maps. More advanced photogrammetric equipment is required to correct for height displacement. Stereoscopic analysis of overlapping aerial photographs allows for three-dimensional interpretation of terrain and features.
Geographic coordinate system & map projectionvishalkedia119
The document discusses geographic coordinate systems and map projections. It defines key concepts like geoid, spheroid, datum, latitude and longitude, projections, and the UTM coordinate system. The UTM system divides the globe into 60 zones, each 6 degrees wide, and uses a Transverse Mercator projection within each zone. UTM coordinates express a point's easting and northing distances in meters from the central meridian and equator/south pole.
This document provides an overview of optical remote sensing. It discusses the different types of optical remote sensing systems including panchromatic, multispectral, super spectral, and hyperspectral imaging systems. It describes the key characteristics and capabilities of each type of system. The document also discusses resolutions in remote sensing including spatial, spectral, temporal, and radiometric resolutions. It outlines several applications of optical remote sensing including urban mapping, hydrological monitoring, environmental monitoring, agriculture/forestry, and hazard identification. Finally, it lists some examples of data sources for different types of optical remote sensing systems.
A Digital Terrain Model (DTM) is a digital file that provides a detailed 3D representation of the topography of the Earth's surface. It consists of terrain elevations at regularly spaced intervals that can be used to create 3D visualizations and analyze slope, aspect, height, and other topographical features. DTMs with draped aerial imagery can help with planning, engineering, and environmental impact assessments by providing accurate 3D models of land surfaces. They are used across a variety of industries and applications.
Remote sensing began with aerial photography in the 1800s. It involves collecting data about the Earth's surface from a distance using electromagnetic sensors. Vertical aerial photographs are important for remote sensing as they have minimal distortion and can be used to take measurements. Photogrammetry allows calculating scale and measurements from aerial photos using factors like focal length and aircraft height. Stereopairs of aerial photos enable measuring terrain height differences through parallax, similar to how human binocular vision perceives depth.
Aerial photography involves taking photographs from aircraft and is used for mapping and studying the Earth's surface. It has various uses like making pictorial representations, preparing base maps, photo interpretation, and expediting natural resource surveys. Factors like atmospheric conditions, aircraft, camera, and film processing influence aerial photographs. There are different types of aerial photographs based on the camera axis position and various stages involved in planning and executing aerial photography flights.
This document discusses the basic principles of photogrammetry. It defines photogrammetry as obtaining spatial measurements and geometrically reliable products from photographs. It describes the different types of analysis procedures and photogrammetric operations used, from simple to sophisticated digital techniques. It outlines common photogrammetric activities like producing maps, determining heights and elevations, and preparing flight plans. It also details the geometric characteristics of aerial photographs, elements, scales, distortions like relief displacement and parallax.
Geometry and types of aerial photographsPooja Kumari
The document summarizes key properties and types of aerial photographs. It discusses that aerial photographs have angles and scales as important geometric properties. It describes the different types of photographs based on the camera axis direction (vertical, oblique, etc.), angle of coverage, film used (black and white, infrared, color), and scale determined by focal length and height. It provides details on vertical, low and high oblique, convergent, and trimetrogon photographs.
Photogrammetry is the science of obtaining information about physical objects through photographs, without needing direct contact. It involves measuring and analyzing captured images. The name comes from Greek roots meaning "light", "drawing", and "to measure". Key developments included using photography for mapmaking in the 1840s-1850s, the photogrammetric stereoplotter in the 1890s, and aerial photography from balloons and planes in the 1860s-1900s, advancing the field into the digital era.
Image classification and land cover mappingKabir Uddin
The document introduces land cover mapping techniques using satellite images, noting that land cover represents physical materials on Earth's surface and can be mapped through analysis of remotely sensed imagery or field surveys, with accurate land cover information supporting applications like planning, disaster management, and policy development.
The document discusses different types of scanning systems used to collect remote sensing data. It describes whiskbroom scanners that use rotating mirrors to scan perpendicular to the flight path, building up images line-by-line. Pushbroom scanners use linear detector arrays that collect entire lines of pixels simultaneously as the sensor moves. Circular scanners employ rotating mirrors to scan in circular patterns, while side-scanning uses active radar to illuminate terrain to one side of the flight path. The characteristics of Landsat, SPOT, and sensor technologies are also overviewed.
The document summarizes a project to create an accurate slope model for Jefferson County, West Virginia using Light Detection and Ranging (LiDAR) data. Field measurements of slope were taken at 34 locations and compared to slope models derived from 10-meter, 3-meter, and 1-meter digital elevation models. The 1-meter LiDAR data was found to most accurately represent the terrain with a higher R2 value and finer detail. The created slope model using this data could potentially be used for planning purposes when combined with other data layers.
This document discusses different coordinate systems used to define locations on Earth. It describes the Everest spheroid, which defines India's geodetic datum. It then explains geographic and geocentric coordinate systems. The geographic system uses latitude and longitude based on a spherical model of Earth. The geocentric system assigns each point an (x,y,z) coordinate using a Cartesian grid with origins at Earth's center. The document provides formulas to convert between the two systems.
This document discusses stereoscopy and parallax measurement in aerial photography. Stereoscopy uses two photographs of the same ground area taken from separate positions to create a stereo pair that enables three-dimensional viewing. Parallax is the displacement of an object caused by a change in the point of observation. Stereoscopic parallax occurs when photographs are taken of the same object from different positions, allowing measurement of differences in elevation.
This document discusses various techniques for analyzing aerial photographs, including:
- Calculating the scale of photographs based on known distances and camera specifications. Scale expresses the ratio of distances on the photo to distances on the ground.
- Determining the heights of objects visible in photos using relief displacement, which measures the difference in an object's appearance between the top and bottom due to perspective.
- Planning flight paths to ensure adequate overlap between consecutive aerial photos for stereoscopic analysis and 3D modeling.
- Using a stereoscope to merge overlapping photo pairs and perceive depth and parallax differences between matching points in the stereo pair.
Geodesy - Definition, Types, Uses and ApplicationsAhmed Nassar
literature review speaks about the geodesy and its relation to the figure of the earth. The definition of geodesy and the imagining of the earth's shape evolution throughout history, it passed at many important developments. We will discuss that geodesy almost interferes with all Geo- and Space sciences, by clarifying some of its uses and applications.
Aerial photographs and their interpretationSumant Diwakar
Aerial photographs provide valuable information about the coastal and terrestrial environment when interpreted correctly. Vertical aerial photographs can be used to update existing maps and create new maps. Simple instruments can be used to correct horizontal distortion in aerial photographs and transfer information to line maps. More advanced photogrammetric equipment is required to correct for height displacement. Stereoscopic analysis of overlapping aerial photographs allows for three-dimensional interpretation of terrain and features.
Geographic coordinate system & map projectionvishalkedia119
The document discusses geographic coordinate systems and map projections. It defines key concepts like geoid, spheroid, datum, latitude and longitude, projections, and the UTM coordinate system. The UTM system divides the globe into 60 zones, each 6 degrees wide, and uses a Transverse Mercator projection within each zone. UTM coordinates express a point's easting and northing distances in meters from the central meridian and equator/south pole.
This document provides an overview of optical remote sensing. It discusses the different types of optical remote sensing systems including panchromatic, multispectral, super spectral, and hyperspectral imaging systems. It describes the key characteristics and capabilities of each type of system. The document also discusses resolutions in remote sensing including spatial, spectral, temporal, and radiometric resolutions. It outlines several applications of optical remote sensing including urban mapping, hydrological monitoring, environmental monitoring, agriculture/forestry, and hazard identification. Finally, it lists some examples of data sources for different types of optical remote sensing systems.
A Digital Terrain Model (DTM) is a digital file that provides a detailed 3D representation of the topography of the Earth's surface. It consists of terrain elevations at regularly spaced intervals that can be used to create 3D visualizations and analyze slope, aspect, height, and other topographical features. DTMs with draped aerial imagery can help with planning, engineering, and environmental impact assessments by providing accurate 3D models of land surfaces. They are used across a variety of industries and applications.
Remote sensing began with aerial photography in the 1800s. It involves collecting data about the Earth's surface from a distance using electromagnetic sensors. Vertical aerial photographs are important for remote sensing as they have minimal distortion and can be used to take measurements. Photogrammetry allows calculating scale and measurements from aerial photos using factors like focal length and aircraft height. Stereopairs of aerial photos enable measuring terrain height differences through parallax, similar to how human binocular vision perceives depth.
Aerial photography involves taking photographs from aircraft and is used for mapping and studying the Earth's surface. It has various uses like making pictorial representations, preparing base maps, photo interpretation, and expediting natural resource surveys. Factors like atmospheric conditions, aircraft, camera, and film processing influence aerial photographs. There are different types of aerial photographs based on the camera axis position and various stages involved in planning and executing aerial photography flights.
This document discusses the basic principles of photogrammetry. It defines photogrammetry as obtaining spatial measurements and geometrically reliable products from photographs. It describes the different types of analysis procedures and photogrammetric operations used, from simple to sophisticated digital techniques. It outlines common photogrammetric activities like producing maps, determining heights and elevations, and preparing flight plans. It also details the geometric characteristics of aerial photographs, elements, scales, distortions like relief displacement and parallax.
Geometry and types of aerial photographsPooja Kumari
The document summarizes key properties and types of aerial photographs. It discusses that aerial photographs have angles and scales as important geometric properties. It describes the different types of photographs based on the camera axis direction (vertical, oblique, etc.), angle of coverage, film used (black and white, infrared, color), and scale determined by focal length and height. It provides details on vertical, low and high oblique, convergent, and trimetrogon photographs.
Photogrammetry is the science of obtaining information about physical objects through photographs, without needing direct contact. It involves measuring and analyzing captured images. The name comes from Greek roots meaning "light", "drawing", and "to measure". Key developments included using photography for mapmaking in the 1840s-1850s, the photogrammetric stereoplotter in the 1890s, and aerial photography from balloons and planes in the 1860s-1900s, advancing the field into the digital era.
Image classification and land cover mappingKabir Uddin
The document introduces land cover mapping techniques using satellite images, noting that land cover represents physical materials on Earth's surface and can be mapped through analysis of remotely sensed imagery or field surveys, with accurate land cover information supporting applications like planning, disaster management, and policy development.
The document discusses different types of scanning systems used to collect remote sensing data. It describes whiskbroom scanners that use rotating mirrors to scan perpendicular to the flight path, building up images line-by-line. Pushbroom scanners use linear detector arrays that collect entire lines of pixels simultaneously as the sensor moves. Circular scanners employ rotating mirrors to scan in circular patterns, while side-scanning uses active radar to illuminate terrain to one side of the flight path. The characteristics of Landsat, SPOT, and sensor technologies are also overviewed.
The document summarizes a project to create an accurate slope model for Jefferson County, West Virginia using Light Detection and Ranging (LiDAR) data. Field measurements of slope were taken at 34 locations and compared to slope models derived from 10-meter, 3-meter, and 1-meter digital elevation models. The 1-meter LiDAR data was found to most accurately represent the terrain with a higher R2 value and finer detail. The created slope model using this data could potentially be used for planning purposes when combined with other data layers.
2. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
agenda
• background
• problem statement
• NA approach
• INS/GNSS gravimetry: geodesy as usual
• future
2
3. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
background
3
4. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
gravimetry – what is it?
4
• geophysical method to measure the
gravity field of the Earth.
5. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
gravimetry – what is it?
5
• geophysical method to measure the
gravity field of the Earth.
• helps the understanding of mass
transport phenomena within our planet, in
the oceans and atmosphere
6. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
6
geodetic motivation
• sea-level rise
• river flooding
• coastal flooding from hurricane
• ...
7. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
gravimetry - applications
• precise terrestrial reference frame
• local geoid determination
7
8. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
gravimetry - applications
• precise terrestrial reference frame
• local geoid determination
8
• volcano monitoring
• glaciers melting monitoring
• plate boundaries
• deformation measurements
• eartquake tectonic studies
9. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
gravimetry - applications
• precise terrestrial reference frame
• local geoid determination
9
• volcano monitoring
• glaciers melting monitoring
• plate boundaries
• deformation measurements
• eartquake tectonic studies
• Natural resources (i.e. Mineral exploration)
10. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
gravimetry – measurement methods
10
GLOBAL REGIONAL LOCAL
CHAMP (> 600 km)
GRACE (> 270 km)
GOCE (> 70 km) terrestrial
10 km100 km1000 km 1 km
11. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
gravimetry – measurement methods
11
Kinematic gravimetry
(> 1 km)
GLOBAL REGIONAL LOCAL
CHAMP (> 600 km)
GRACE (> 270 km)
GOCE (> 70 km) terrestrial
10 km100 km1000 km 1 km
12. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
12
Airborne gravity is the only
technique that can
adequately connect existing
terrestrial data to existing
ship and altimetry data in
the oceans and fill coverage
gaps.
Airborne data will not
replace existing data, but
will be used as a baseline for
correcting that data to be
consistent across the
country.
13. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
13
airborne gravimetry
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14
airborne gravimetry
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problem statement
15
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kinematic gravimetry (KG) - concept
1950’s: placing gravimeters
onboard vehicles
16
rapid and high-resolution
surveys in oceans, polar
regions, high mountains,
tropical forests...
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17
The first LaCoste-Romberg
Model “S” Air-Sea
Gravimeter.
1958 - Air force Geophysics Lab
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18
LaCoste-Romberg Model “S”
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LaCoste-Romberg TAGS-6
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BGM-3 Gravimeter - Bell Aerospace
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Sea Gravimeter KSS31. Bodenseewerk Geosystem GmbH
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22
Chekan-A Gravimeter
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23
1965 - Carson Services, Inc.
24. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
kinematic gravimetry (KG) - concept
1950’s: placing gravimeters
onboard vehicles
1960’s: INS was introduced
as as surveying instrument
24
positioning limited by the
unknown anomalous
gravity field
25. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
kinematic gravimetry (KG) - concept
1950’s: placing gravimeters
onboard vehicles
1960’s: INS was introduced
as as surveying instrument
25
positioning limited by the
unknown anomalous
gravity field
gravity field will be recovered from INS
measurements if accurate kinematic
positions and velocities are known and
the system errors are kept small
26. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
26
INS used for airborne gravimetry
27. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
kinematic gravimetry (KG) - concept
1950’s: placing gravimeters
onboard vehicles
1960’s: INS was introduced
as as surveying instrument
1980’s: GPS represented
the opportunity to measure a
with adequate accuracy and
precision
27
28. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
28
Rampant Lion project
29. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
kinematic gravimetry (KG) - concept
1950’s: placing gravimeters
onboard vehicles
1960’s: INS was introduced
as as surveying instrument
1980’s: GPS represented
the opportunity to measure a
with adequate accuracy and
precision
29
gravity computation is easy,
in principle ...
30. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
... but, gravity computation is hard
30
• very dynamic environtment:
• noise-to-signal ratios > 1000
• largest contributions to noise:
• high frequency noise (vibration)
• noise amplification when computing
accelerations
GNSS INS
meas. principle dist. from time delays inertial accel.
system operation reliance on space segment autonomous
output variables position, time position, orientation
long-wave. errors low high
short-wave. errors high low
data rate low (1Hz) high (≥ 25Hz)
instrument cost low high
INS/GNSS
limiting factors
31. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
airborne gravimetry - operational constraints
• navigation system used to position the aircraft
• aircraft speed: compromise between low vibrations (high
speed) and high spatial resolution (low speed)
• flight altitude: the signal to noise ratio improve with a lower
altitude
• use of an autopilot: to provide both smoother flight path and
the maintenance of a reference altitude
• weather condition: low turbulence is essential if high
frequency aircraft accelerations are to be avoided
• design of the aircraft
• design of the survey
31
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airborne gravity survey
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airborne gravity survey
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KG - mathematical models
34
INS navigation equations
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stochastic processes
INS/GNSS gravimetry – traditional approach
35
apriori stochastic info from manufacturer’s,
tricky calibrations and field testing modelling
36. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
INS/GNSS-g – traditional approach
36
process noises:
where
dynamical system
State Space Approach (SSA)
• prediction, Kalman filtering and
smoothing
• generates and optimal estimates, but
not the best
• cannot use all the observational info.
• disadvantage trying to deal with space
correlations (i.e. crossover points)
37. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
INS/GPS-g – SSA methodology
37
STATE SPACE APPROACH
prediction + KF + smoothing
STOCHASTIC TIME SERIES
• stochastic differential equations
• state vector
• observations
Sander Geophysics
US Naval Research Lab
Geomatics Canada
KMS
AGMASCO
ITC Moscow
Intermap
Univ. of Calgary (UofC
Univ. Porto
• scalar: L&R + platform + DGPS
• scalar/vector: INS/GNNS
38. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
INS/GPS-g – SSA methodology
38
STATE SPACE APPROACH
prediction + KF + smoothing
STOCHASTIC TIME SERIES
• stochastic differential equations
• state vector
• observations
• scalar: L&R + platform + DGPS
• scalar/vector: INS/GNNS
Kananaskis (UofC, 1995)
Skagerrak (AGMASCO, 1996)
Azores (AGMASCO, 1997)
Greenland (UofC-KMS, 1998)
Greenland, Baltic Sea, Great
Barrier Reef (KMS, 1999)
Alexandria (UofC, 2000)
Greenland (KMS, 2000)
Greenland, Crete, Corsica
(KMS, 2001)
Geophysical surveys
(Intermap, Sander Geophysics)
43. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
43
Greenland Aerogeophysical project 1991-92
• US Naval Research Lab
• NOAA
• Danish National Survey (now DTU-Space)
• NIMA (now NGA)
44. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
44
ArcGP
1992-2003
45. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
45
Arctic gravity project
46. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
46
Malaysia 2002-3
47. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
47
Rampant Lion project - Afghanistan 2006,2008
48. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
NA approach
48
49. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
INS/GNSS-g – Network Approach
49
Network Approach (NA)
• observation equations
• least-squares adjustment (LSA)
• the key to overcome SSA limitations is to look
as stochastic differential equations (SDE)
• discretisation
leads to a geodetic network new
approach
Geodesy
as usual
50. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
NA – network approach
• general advantages:
• parameters related by observations regardless of time
• networks can be static and/or dynamic
• covariance information can be computed selectively
• variance component estimation can be performed
• INS/GNSS gravimetry advantages:
• rigorous Earth gravity modelling
• better exploiting of external observational information
• more information for further geoid determination
• drawback:
• cannot be applied to real-time navigation
50
51. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
INS/GPS-g – approaches
PAST PRESENT FUTURE
51
NETWORK APPROACH
least-squares network adjustment
CLASSICAL NETWORKS
• static model, param. and obs.
NEW NETWORK APPROACH
• dynamic observation model
• static observation model
• time dependent parameters
(stochastic processes)
• time independent parameters
(random variable)
• independent observations
STATE SPACE APPROACH
prediction + KF + smoothing
STOCHASTIC TIME SERIES
• stochastic differential equations
• state vector
• observations
STOCHASTIC
TIME SERIES
STATIC
NETWORKS
TIME DEPENDENT NETWORKS
52. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
INS/GNSS-g – NA approaches
CLASSICAL NET TIME DEPENDENT NET
52
Termens,A., Colomina,I. Network
approach versus state-space
approach for strapdown inertial
kinematic gravimetry. GGSM2004,
IAG Symposia Vol. 129, pp.
107-112
Termens,A. A Network Approach
for Strapdown Inertial Kinematic
Gravimetry. Ph.D.
Colomina,I., Blázquez,M. A unified
approach to static and dynamic
modelling in photogrammetry and
remote sensing. International
Archives of the Photogrammetry,
Remote Sensing and Spatial
Information Sciences 35(B1). pp.
178-183
GAL FP7-287193 project “Galileo
for Gravity”
GAL final review. Castelldefels,
2014-02-10.
2004
2012
2014
...
53. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
INS/GNSS-g – NA approaches
CLASSICAL NET TIME DEPENDENT NET
53
Termens,A., Colomina,I. Network
approach versus state-space
approach for strapdown inertial
kinematic gravimetry. GGSM2004,
IAG Symposia Vol. 129, pp.
107-112
Termens,A. A Network Approach
for Strapdown Inertial Kinematic
Gravimetry. Ph.D.
Colomina,I., Blázquez,M. A unified
approach to static and dynamic
modelling in photogrammetry and
remote sensing. International
Archives of the Photogrammetry,
Remote Sensing and Spatial
Information Sciences 35(B1). pp.
178-183
GAL FP7-287193 project “Galileo
for Gravity”
2004
2012
2014
...
GeoTeX
GENA
54. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
INS/GNSS gravimetry:
geodesy as usual
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55. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
ICC GeoTeX package (1988 - )
• adopts a simple adjustment oriented point of view
• main data types: observations, parameters and sensors.
• Functional model
• FORTRAN-90 dynamic memory 32-bit implementation
55
56. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
GeoTeX functional model implementation
56
discretization
deriva1:
midpoint or
leap-frog
stochastic process Hz(INS)
Hz(cal)
Hz(g)
interpolation
intp: nearest point
RW process
57. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
INS/GNSS-g GeoTeX models
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gravity
GNSS
INS
equations
58. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
GeoTeX WIB – INS angular rate vector model
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Euler angles differential equations:
equivalent equations in terms of quaternions:
GeoTeX/ACX functional model
59. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
GeoTeX gravity parameters
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DG-P
G-P
GRAVITY-P
G-P
DG-P
65. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
gravimetry – measurement methods
65
Kinematic gravimetry
(> 1 km)
GLOBAL REGIONAL LOCAL
CHAMP (> 600 km)
GRACE (> 270 km)
GOCE (> 70 km) terrestrial
10 km100 km1000 km 1 km
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alternative survey platforms ?
67. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
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airborne gravimetry
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alternative survey platforms ?
69. M. Assumpció Termens, 2017-05-09, Enginyeria en Geoinformació i Geomàtica
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global gravity … long-wavelength help aerogravity
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satellite gravity: GOCE