Tag: Geodesy

Direct and Inverse

There are two standard problems in geodesy: Direct geodetic problem — Given a point on the Earth (latitude and longitude) and the direction (azimuth) and distance from that point to a second point, determine the latitude and longitude of that second point. Inverse geodetic

Posted in Algorithms Tagged with: ,

IAU Rotation Models

The IAU Working Group on Cartographic Coordinates and Rotational Elements (WGCCRE) is the keeper of official models that describe the cartographic coordinates and rotational elements of planetary bodies (such as the Earth, satellites, minor planets, and comets).  Periodically, they release a report containing the coefficients

Posted in Orbital Mechanics, Programming Tagged with: , , , ,

Nonsingular Geopotential Models

The gravitational potential of a non-homogeneous celestial body at radius , latitude , and longitude can be represented in spherical coordinates as: Where is the radius of the body, is the gravitational parameter of the body, and  are spherical harmonic coefficients,

Posted in Programming Tagged with: , , , ,

Direct Geodetic Problem

The “direct” geodetic problem is: given the latitude and longitude of one point and the azimuth and distance to a second point, determine the latitude and longitude of that second point.  The solution can be obtained using the algorithm by Polish

Posted in Algorithms, Programming Tagged with: ,

Cartesian to Geodetic

For many years, I have used the closed-form solution from Heikkinen [1] for converting Cartesian coordinates to geodetic latitude and altitude.  I’ve never actually seen the original reference (which is in German).  I coded up the algorithm from the table given

Posted in Algorithms, Programming Tagged with: ,