# Approved Orbit-Relative Reference Frames

**Policy**: Expert Review

**Authority**: CCSDS.MOIMS.NAV

**OID**: 1.3.112.4.57.3

**Notes**:

This registry contains allowable values for specifying orbit-relative reference frames in the accompanying referenced standards. These frames can be used to specify maneuver and covariance data.**Note that these orbit-relative local reference frames below are provided in two flavors: inertial and rotating. When transforming velocity terms between inertial and rotating frames, remember to properly incorporate the contribution.**

## Contents

**16** records in registry

#### Object Identifier

#### Label

Details | Status | Name | Description | Others Have Referred To This As | References | OID | |
---|---|---|---|---|---|---|---|

Assigned |
EQW_INERTIAL |
Equinoctial Coordinate System, a quasi-inertial, right-handed, Cartesian frame with E aligned with the ascending node direction, W along the orbital angular momentum vector (\(\vec{w} = \vec{r} × \vec{v}\)) and Q completing the set (\(\widehat{Q} = \widehat{W} × \widehat{E}\)). This system is quasi-inertial in the sense that it is treated as an inertial coordinate frame that is redefined at each time of interest. |
— |
1.3.112.4.57.3.1 |
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Assigned |
LVLH_ROTATING |
‘LVLH’ stands for ‘Local Vertical Local Horizontal’. The Z-axis of the rotating LVLH frame is a unit vector collinear and opposite sign of the gravicentric satellite position (planet center, spacecraft gravity center), the Y-axis is a unit vector collinear but with the opposite sign of the orbital kinetic momentum (normal to orbit plane), and the X-axis is the unit vector equal to \(\vec{Y} \times \vec{Z}\) |
— |
1.3.112.4.57.3.2 |
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Assigned |
LVLH_INERTIAL |
A quasi-inertial version of the LVLH_ROTATING frame. This system is quasi-inertial in the sense that it is treated as an inertial coordinate frame that is redefined at each time of interest. |
— |
1.3.112.4.57.3.3 |
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Assigned |
NSW_ROTATING |
“Nadir, Sun, Normal” – This rotating frame aligns the x-axis in the nadir direction, the y-axis as much as possible toward the Sun while still being normal to the x-axis, and the z-axis completing the right-hand set. |
— |
1.3.112.4.57.3.4 |
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Assigned |
NSW_INERTIAL |
A quasi-inertial version of the NSW_ROTATING frame. This system is quasi-inertial in the sense that it is treated as an inertial coordinate frame that is redefined at each time of interest. |
— |
1.3.112.4.57.3.5 |
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Assigned |
NTW_ROTATING |
A local orbital coordinate rotating frame that has the y-axis along the Tangential (or inertial velocity) vector, z-axis (“W”) along the orbital angular momentum vector (\(\vec{w} = \vec{r} × \vec{v}\)), and N (the x-axis) completing the right handed system (i.e., for a circular orbit “N” generally points in the radial direction and for an eccentric orbit, “N” points as close to radial as possible while still being normal to the T-W plane). |
Transverse-Velocity-Normal (TVN) frame (e.g., CCSDS CDM Blue Book 508.0-B-1). |
1.3.112.4.57.3.6 |
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Assigned |
NTW_INERTIAL |
A quasi-inertial version of the NTW_ROTATING frame. This system is quasi-inertial in the sense that it is treated as an inertial coordinate frame that is redefined at each time of interest. |
— |
1.3.112.4.57.3.7 |
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Assigned |
PQW_INERTIAL |
Perifocal Coordinate System, a quasi-inertial frame with P axis pointing to periapsis, W along the orbital angular momentum vector (\(\vec{w} = \vec{r} × \vec{v}\)) and Q completing the set (\(\widehat{Q} = \widehat{W} × \widehat{P}\)). This system is quasi-inertial in the sense that it is treated as an inertial coordinate frame that is redefined at each time of interest. |
— |
1.3.112.4.57.3.8 |
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Assigned |
RSW_ROTATING |
A Radial, Along track, Cross track, local orbital coordinate rotating frame, where the R axis always points out from the satellite along the central body’s radius vector to the satellite as it moves through the orbit. The S axis is in the direction of (but not necessarily parallel to) the velocity vector and is perpendicular to the radius vector. The W axis is aligned with the orbit angular momentum vector. Note that the RSW_ROTATING frame is also referred to as: |
• Gaussian Coordinate System |
1.3.112.4.57.3.9 |
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Assigned |
RSW_INERTIAL |
A quasi-inertial version of the RSW_ROTATING frame. This system is quasi-inertial in the sense that it is treated as an inertial coordinate frame that is redefined at each time of interest. |
• ‘Radial, Down-track, Cross-track’ (UVW) |
1.3.112.4.57.3.10 |
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Assigned |
TNW_ROTATING |
A local orbital coordinate Tangential, Normal, Cross-track rotating frame that has the x-axis along the Tangential (or velocity) vector, z-axis (“W”) along the orbital angular momentum vector (\(\vec{w} = \vec{r} × \vec{v}\)), and N completing the right handed system (i.e., for a circular orbit “N” generally points in the Nadir direction and for an eccentric orbit, “N” points as close to Nadir as possible while still being normal to the T-W plane). Note that while this frame has the same axes defined as in the NTW frame, the ordering of axes is different (TNW). |
— |
1.3.112.4.57.3.11 |
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Assigned |
TNW_INERTIAL |
A quasi-inertial version of the TNW_ROTATING frame. This system is quasi-inertial in the sense that it is treated as an inertial coordinate frame that is redefined at each time of interest. |
— |
1.3.112.4.57.3.12 |
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Assigned |
SEZ_ROTATING |
The South/East/Zenith (SEZ) topocentric horizon system. This system is a right-handed, Cartesian system rotating with the observing site. The local horizon forms the fundamental plane, with the S axis pointing due south from the site (even in the Southern Hemisphere). The E axis points east from the site and is undefined at the North or South Poles. The Z axis (zenith) points radially outward from the site, along the site’s geodetic local vertical. |
— |
1.3.112.4.57.3.13 |
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Assigned |
SEZ_INERTIAL |
A quasi-inertial version of the SEZ_ROTATING frame. This system is quasi-inertial in the sense that it is treated as an inertial coordinate frame that is redefined at each time of interest. |
— |
1.3.112.4.57.3.14 |
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Assigned |
VNC_ROTATING |
A local orbital coordinate Velocity, Normal, Co-normal rotating frame that has the x-axis along the Velocity (or tangential) vector, y-axis Normal to the orbit along the orbital angular momentum vector (\(\vec{w} = \vec{r} × \vec{v}\)), and z-axis is the “Co-normal” direction completing the right handed system (i.e., for a circular orbit “C” points in the radius vector direction whereas for an eccentric orbit, “C” points as close to radial as possible while still being normal to the V-N plane). Note that while this frame has the same axes defined as in the NTW frame, the ordering of axes is different (i.e., TWN). |
‘Velocity, Normal, Bi-normal’ ( |
1.3.112.4.57.3.15 |
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Assigned |
VNC_INERTIAL |
A quasi-inertial version of the ‘Velocity, Normal, Co-normal’ VNC_ROTATING frame. This system is quasi-inertial in the sense that it is treated as an inertial coordinate frame that is redefined at each time of interest. |
‘Velocity, Normal, Bi-normal – quasi-inertial’ ( |
1.3.112.4.57.3.16 |