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11 votes

Object slowest at periapsis - despite correct position calculation

If I understand correctly, your $p, q$ are essentially cartesian coordinates, and you're trying to get the velocity components in those two orthogonal directions. However, you're taking the derivative ...
uhoh's user avatar
  • 149k
9 votes
Accepted

Object slowest at periapsis - despite correct position calculation

As uhoh said, the velocity is the derivative of the position w.r.t. to time, not true anomaly. I.e., if we denote time by $t$, the components of the velocity vector are $\left(\frac{dp}{dt}, \frac{dq}{...
Litho's user avatar
  • 2,050
5 votes

What does a "handover" really mean in satellite communications?

This might become clearer if you can think in terms of what the ground station is there to do and what assets it has to do so. Its a resource management issue. e.g. if the number of antennas the ...
Puffin's user avatar
  • 9,654
4 votes

Converting Keplerian Orbital Elements into 2D State Vectors in Unity C#

Things wind up changing when you look at hyperbolic orbits instead of elliptical ones when going from cartesian vectors to Keplerian elements, because when you use the elliptical equations some of the ...
notovny's user avatar
  • 5,524
4 votes
Accepted

Orbit Determination from Position and Velocity

First, some caveats: Always use the gravitational mass parameter $\mu_\text{body}$ rather than the product $GM_\text{body}$. The gravitational mass parameter $\mu_\text{body}$ conceptually is the ...
David Hammen's user avatar
3 votes

Integration of Varying Forces, Impulses in Simulators

Now I'm using an RK4 integrator, (1st case) we assume that the forces are uniform all throughout one integration time step. (is this correct?) That is not correct. The point of using a multiple stage ...
David Hammen's user avatar
3 votes

What does a "handover" really mean in satellite communications?

In general, handovers happen when a device that has single upstream connection switches between access points that are serving multiple devices each. In mobile telephones, your phone does a handover ...
jpa's user avatar
  • 2,526
2 votes

Difference in using flat earth or round earth model for equation of motion

Spherical geometry is quite different than cartesian trigonometry.. the sum of all angles in a triangle can be up to 540°, distances are different etc. particular the initial choice of flight angle w....
AtmosphericPrisonEscape's user avatar
2 votes

How to simulate the environment of the moon for rovers on earth?

Parts of the rover, such as the suspension, drive train, and autonomous decision making, navigation, and obstacle avoidance capabilities can tested by creating a multi-physics model of the rover and ...
phil1008's user avatar
  • 6,186
1 vote

What are some best practices for coding a satellite orbit propagator and ground track plotter?

For anyone interested, here's what I have for now: https://satellite-propagator.vercel.app/ I'm still building out most of the features I want it to have (and a lot of it is unfinished, along with ...
gaharaz's user avatar
  • 121
1 vote

Integration of Varying Forces, Impulses in Simulators

Here's a theory I have about how one could implement an impulse with an RK4 integrator. I believe the formal answer is that the force can be expressed as F(t). The right way to apply an RK4 is to ...
Steven Dorsher's user avatar
1 vote

How to get contact locator events in GMAT using Python

I am trying to do the same thing, so if you have found an answer please post it! One method that does work is to generate and run a script using the gmat objects, so I am doing: - ...
Mike Gadsdon's user avatar
1 vote

Difference in using flat earth or round earth model for equation of motion

I'll dip my toe into the quicksand and try not fall in. Spaceflight math dates back to the era of pocket protectors and slide rules. If you needed more digits to say multiply or take a square root, ...
uhoh's user avatar
  • 149k

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