Geodetic Coordinates: Computing Latitude and Longitude

In this video we show how to compute the geodetic latitude and terrestrial longitude if given the velocity north and east. This is useful for simulating a body moving over a spheroid Earth model.
Topics and timestamps:
0:00 - Introduction
0:10 - Terrestrial longitude, geodetic latitude, geodetic altitude
9:09 - Meridian radius of curvature, prime vertical radius of curvature
19:55 - Computing time rate of change of latitude and longitude
27:25 - Simulink implementation
Lecture notes and code can be downloaded from github.com/clum/KZbin/tree/...
References:
- Krakiwsky, Edward J., and Thomson, Donald B. “Geodetic Position Computations No. NB-DSE-TR-39.
Department of Surveying Engineering, University of New Brunswick, 1974. (www2.unb.ca/gge/Pubs/LN39.pdf)
-The Navigation Equations: Computing Position North, East, and Down ( • The Navigation Equatio... )
-A Nonlinear, 6 DOF Dynamic Model of an Aircraft: the Research Civil Aircraft Model (RCAM) ( • A Nonlinear, 6 DOF Dyn... )
All Flight Mechanics videos in a single playlist ( • Flight Mechanics )
#FlightMechanics
You can support this channel via Patreon at / christopherwlum or by clicking on the ‘Thanks’ button underneath the video. Thank you for your help!

[@ChristopherLum]

In case it is helpful, here are all the Flight Mechanics videos in a single playlist kzbin.info/aero/PLxdnSsBqCrrEx3A6W94sQGClk6Q4YCg-h. You can support this channel via Patreon at www.patreon.com/christopherwlum. Please let me know what you think in the comments. Thanks for watching!

[@armaisdiaz4748]

As an aerospace engineer I must thank you to help me remember all this terms as they are pretty useful to me. Great video, accurate and very well explained.

[@ChristopherLum]

I'm glad it was helpful. There are several related videos on the channel. Please feel free to check them out and I would love to hear what you think in the comments. Thanks for watching!

[@aimeepak717]

AE512: I really appreciate the block diagrams on the white board. It really helps with developing the simulink model. :)

[@jordantriolo571]

AE512: Nice to see a simple explanation on geodetic vs geocentric latitude

[@milesrobertroane955]

AA516: Good video, I am excited to get this visualized!

[@NicholasRehm]

Very familiar with these topics, but new to simulink--love your style of teaching and showing, thanks!

[@ChristopherLum]

Hi Nicholas, Thanks for the kind words, I'm glad you enjoyed the video. If you find these videos helpful, I hope you'll consider supporting the channel via Patreon at www.patreon.com/christopherwlum or via the 'Thanks' button underneath the video. Given your interest in this topic, I'd love to have you a as a Patron as I'm able to talk/interact personally with all Patrons. Thanks for watching! -Chris

[@falgunsukhija2672]

Thank you so much! I am teaching myself astronomy right now and your video was the only place i could find the difference between geodetic and geocentric latitude mentioned clearly

[@mikefochtman7164]

I play around with celestial navigation and this is a fine point that I've wondered. Since maritime navigators measure the star elevation from the local horizontal, I think the positions given in Nautical Almanacs use a 'geodetic declination'?!? Instead of east-west longitude we use hour-angles which are always measured easterly up to 24 hours. And of course we use a point in the constellation Aries as 'prime meridian' in the celestial sphere.

[@AliRazaTajamal]

Amazing stuff. Looking forward to navigation equations

[@smahmud1839]

I am currently pursuing a course on satellite positioning. This video helped me a lot to understand Meridian Radius of curvature and prime vertical radius of curvature. Thanks a lot Mr. Lum.

[@ChristopherLum]

Glad it was helpful!

[@ccball954]

AE512: Important to remember the flat-earth vs. round-earth physics. Thanks-Christian Ball

[@sebastianvaroncrews3634]

Fantastic video! I love your channel now :)

[@ChristopherLum]

Glad you enjoy it!

[@emmanuelsheshi1553]

thanks so much for these videos

[@zaneyosif]

AE512: Great video! I can see how using the RCAM model to output lat/long/altitude can be used to develop some sort of position tracking. Curious whether the desired convention to have our geodetic latitude as phi and that could get confused with our x_state of phi angle and how that is usually differentiated for the user

[@CungToi]

Dear Professor, 12:57 I think M should correspond to the minimum radius of curvature and N is the opposite.

[@ucontrolchannel5967]

Thank youuu verryyy much

[@ChristopherLum]

No problem

[@muhammedeminyavuzaslan9015]

Hi Mr.Lum, im member of the patreon and im really happy about that. Can you share this simulink file with patreon members ? Thanks a lot

[@MedullarisConus]

You are amazing! Do you have a video talking about parans?

[@ChristopherLum]

I'm glad it was helpful. If you have video requests/ideas, you can submit them via www.patreon.com/christopherwlum. Thanks for watching!

[@oguzhancam4011]

Hi. How about making a video about system identification?

[@edwinisdory3250]

Thank you very much. Can we have matlab file explained and constructed so as to run?

[@richardwilmarsalascaballer8746]

Por favor en este ejercicio podría reemplazar las formulas con coordenadas reales (números) porque me quedo la dudad con respecto a los vectores porque ud coloca las mismas incógnitas latitud, longitud y como que la elevación solo cambiaste de signo, no sé si será lo correcto

[@jaziebart]

AA 516 - At 16:10 in the video, is the 1/2 power applied to the entire quantity of the denominator of N?

[@ChristopherLum]

Alex, this is just a result of the geometry. You can see the derivation in Stevens and Lewis if you want to rederive but personally, I'd just use the equations and be done with it 😀

[@alexzhen179]

AA 516: Hello Professor, I have a very stupid question here. What is the block you used in Simulink to contain a simple function? Thank you so much! Very great video. Getting excited about building my own flight simulation.

[@alexzhen179]

I think I found the answer. Seems like MathWorks removed this block since the last version.

[@ChristopherLum]

@@alexzhen179 You might want to try the 'Matlab Fcn' block. Let me know if this isn't in the latest version.

[@alexzhen179]

@@ChristopherLum MATLAB function block works fine in my version (2020b). I substitute all Fcns with the MATLAB functions. Thanks!

[@fuelnfreedom]

Loved ur video nd ur way of explanation. Actually I'm working with a satellite data I'm just confused what's the value of altitude should I take like altitude at which satellite is revolving or altitude at which satellite is recording data like for this case study its 500m from surface

[@ChristopherLum]

Thanks for catching this you are correct!

[@Ricky.Ricardo]

Could you create a video on how to go from geocentric to geodetic coordinate system?

[@ChristopherLum]

Thanks for reaching out. If you have questions or would like to request a video, I hope you'll consider supporting the channel via Patreon at www.patreon.com/christopherwlum. I'd love to have you as a Patron as I'm able to talk/interact personally with Patrons. Thanks for watching!

[@erickdiaz4048]

Mr. Lum, what is your favorite movie?

[@marcosszmania5874]

AE 512 - What is the name of the block you have used to create the Longitude Bound in min 29:31? Also, could you provide the formula for phi_dot (Geodetic Latitude dot) and lambda_dot (Terrestrial Longitude dot) ? Thanks.

[@ChristopherLum]

Marcos, this is something I coded up myself. You can do it using a MATLAB Fcn block

[@Aguvika]

Please, do you have a link to a resource that sows how that equation is derived?

[@ChristopherLum]

Hi, Thanks for reaching out. If you have questions or would like to request a video, I hope you'll consider supporting the channel via Patreon at www.patreon.com/christopherwlum or via the 'Thanks' button underneath the video. I'd love to have you as a Patron as I'm able to talk/interact personally with Patrons. Thanks for watching! -Chris

[@ojasvikamboj6083]

A A 516: Ojasvi Kamboj

[@chayweaver.2995]

AE512: are phi_dot and lambda_dot in radians or degrees per second?

[@ChristopherLum]

Should be in rad/s but it has been a while since I looked at this. Let me know if you think it is deg/s

[@edwardmau5877]

AE 512: What would be an application that uses geocentric latitude?

[@ChristopherLum]

Great question. Sometimes this is helpful for converting between the ECEF frame (effectively going from cartesian to cylindrical coordinates).

[@davidtelgen8114]

AE512: I'm surprised no flat earthers have found this video yet, their comments are always...entertaining 😆

[@ChristopherLum]

Haha, I know. They seemed to have found the video on Coriolis Effect and had some choice comments. Also KZbin automatically tagged the video on the 'Flat Earth Equations of Motion' as being mis-information :)

[@yaffetbedru6612]

AA516

[@syedmdabid7191]

Geodetic latitude= tan^--1 ( b/a tan α. ( α=Geocentric latitude, a, b major and minor axis of the EARTH)

[@dinomoviesnstuff]

What???

[@user-ns7wy1pk9t]

AA516:Po

[@petermay6090]

AA516

[@daniellerogers5959]

AA516