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Questions tagged [coordinates]

The tag has no usage guidance.

2
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1answer
39 views

Map image (x,y) to spherical coordinates [closed]

What is an efficient method to map image pixels (2D-Cartesian) to their spherical coordinates given camera azimuth and elevation? (Ideally, response includes mathematical notation/Python/C++)
1
vote
1answer
42 views

Diagram of Hayabusa 2 in “Hill Coordinate System”; what is that exactly? How to convert it to inertial?

These JAXA's Hayabusa-2's two Tweets: 1 2 show a diagram of the spacecraft's motion relative to Ruygu in what they call a Hill Coordinate System, This is a diagram of the trajectory during solar ...
2
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1answer
85 views

Calculating the radial, in-track and cross-track distances

I'm computing the relative distances between satellites. The following picture shows the distances, which are considered as risky. What do Radial, In-track and Cross-track mean and why are they ...
4
votes
1answer
58 views

Accuracy of ECI (J2000) to ECEF (WGS84) for a LEO satellite only accounting for Earth Rotation

I am working on developing a simple J2 orbit propagator for a project I am working on and am at the stages of converting from ECI to ECEF. Looking at this reference document in section 2.4, what ...
3
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0answers
106 views

Why would someone use Modified Rodrigues Parameters over Quaternions for spacecraft attitude estimation? And vice versa?

I see quite some papers on spacecraft attitude determination and control, that rely on quaternions. While some others rely on MRPs. The advantage that I see so far is that... for quaternions, the ...
2
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0answers
61 views

Spacecraft-fixed coordinate system

I am working with data from a polar-orbiting satellite (inclination 97 degrees) with limited attitude information. I am trying to define a coordinate system which is fixed with respect to the ...
5
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2answers
101 views

Does a solar geometry library exist for satellites in LEO?

I'm looking for a solar geometry library built for a cubesat in LEO. In my research so far, I've discovered the MINES Paris-Tech Solar Geometry 2 library (http://www.oie.mines-paristech.fr/...
2
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0answers
55 views

Transformation between ICRF and Fixed in STK

I am building a satellite orbit propagator in MATLAB and I am using STK as a reference. Comparing TwoBody propagator using RKN78 (MATLAB) with HPOP (degree 1, order 1), I am getting quite good ...
6
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2answers
286 views

Is it possible to plot the ground track of a satellite with just azimuth & elevation angles without range?

I came across this question on StackOverflow about Satellite Trajectory plot. In the code mentioned in the question, the user takes only the Azimuth & Elevation angles (radians) & converts ...
4
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1answer
102 views

What are the problems that need to be taken in consideration when trying to find planetary position by using jpl ephemerides?

I'm currently trying to determine the position of the sun and the moon from jpl ephemeris DE200 which is referred to the dynamical equator and equinox of 2000 and uses tdb time. I am using the j2000 ...
2
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0answers
80 views

Will these equations give me the approximate apparent RA and Dec using positions from Horizons?

In this answer @DavidHammen showed me how to get coordinates from JPL's Horizons using the Earth's equatorial plane as a reference plane by selecting ...
3
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1answer
114 views

Shape and dimensions of the Moon's reference surface for selenographic latitude/longitude?

For Earth, the reference surface for "GPS" latitude, longitude, and altitude is the WGS84 ellipsoid, with equatorial and polar radii $a, b$ of 6378.1370 and 6356.7523 kilometers, respectively. ...
5
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1answer
481 views

TLE SGP4 Coordinate Transformations

I am working on developing a user friendly SGP4 orbit propagator in C on a PIC24. I have extensively read Revisiting Spacetrack Report #3 and celestrak - there are a few outstanding questions I have....
0
votes
1answer
1k views

Algorithm to convert from ECEF coordinates to ECI coordinates

I am looking for an Algorithm (the formulas; not the code) to convert from ECEF coordinates to ECI coordinates. I have a MATLAB code for it but am unable to understand certain things. So it'd be ...
3
votes
1answer
1k views

How to calculate the current position of a satellite?

I want to write a SIMULINK model that calculates the position visible of satellites for the current time. As input for the model I have the coordinates of a location, the current time and the ...
3
votes
2answers
934 views

Computing GEO satellite's longitude from elevation/azimuth from a given latitude/longitude?

This question is a bit of a mix between satellite knowledge and math. Suppose I have the "look angles" (elevation and azimuth) for an otherwise unidentified geostationary satellite, and I would like ...
3
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2answers
147 views

Where to get rectangular coordinates of the solar system planets?

Title, I tried converting the coordinates from here to rectangular but it seems off.
6
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1answer
261 views

What does “Q frame” means in terms of satellite coordinates?

I'm looking at some old satellite documentation which mentions the use of a "Q frame" coordinate system to keep track of the satellite attitude. What does this "Q frame" generally mean in the field of ...
1
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0answers
717 views

Better way to get approximate ground track for a satellite using Skyfield?

I wanted to make a quick ground-track plot, so I used the Python package Skyfield to propagate a TLE and return Earth-Centered Inertial coordinates. Then I created a ...
4
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0answers
55 views

Regarding the vernal equinox and calculate a TLE code

I am utterly confused as to how the ecliptic co ordinate system works. My understanding is that the vernal equinox is comparable to greenwich for longitude here on earth. But how do we know where the ...
5
votes
1answer
203 views

Which side of Europa is which?

I understand that Europa is tidally locked* to Jupiter, so there's a Jovianmost longitude on one side and an anti-Jovian longitude on the other. What I can't figure out is which side is which. ...
5
votes
1answer
241 views

How to (correctly) rotate this data so the Ecliptic is in the XY plane?

When plotting orbits using the Python package Skyfield, the coordinates are barycentric ICRS. This puts the center of mass of the solar system at the origin, but the $\hat{z}$ axis is tilted about 23° ...
4
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2answers
1k views

How is space mapped out?

Here on earth, we have four directions(East, West, North, South). We have earth maps which shows our exact location from any other location in 2D plane. But in space, planets and stars are in three ...
11
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1answer
356 views

Are any spacecraft heading remotely where Planet 9 is expected to be?

Planet 9, the hypothetical planet predicted Batygin and Brown, is expected to have an apoasis near the galactic center. Is there a spacecraft that is heading in that direction? Specifically, they ...
3
votes
1answer
302 views

Latitude and longitude lines for Pluto and Charon

I am hoping someone can point me to images of Pluto and Charon with latitude and longitude lines. I know it's the convention to designate the near point of a tidelocked moon as 0°, 0°. Is the same ...