Yaw, pitch and roll vs. azimuth and elevation

In summary: Interesting video on roll yaw pitch and pan tilt. Owen mentions that "roll" is used for adjusting polarization, but it is more usual to do this by rotating the feed. He also mentions that nowadays you need 3 satellites to get a good signal. This is because azimuth and elevation are not enough to point to a direction. You need to roll or tilt the dish to get the best possible signal.
  • #1
senmeis
69
2
Hi,

Yaw, pitch and roll are used to describe the movement of planes or ships. Azimuth and elevation are used to describe the pointing direction of a dish antenna. Can they be used exchangeably? I think two angles are enough for planes and ships, why 3?

Owen
 
Engineering news on Phys.org
  • #2
They don't describe movement so much as attitude, which is the physical orientation of an object relative to some reference coordinate system. You cannot fully define 3D attitude with only 2 coordinates.
 
  • Like
Likes russ_watters
  • #3
senmeis said:
I think two angles are enough for planes and ships, why 3?
Uh ... you think planes can only move in 2 dimensions?
 
  • Like
Likes sysprog and davenn
  • #4
senmeis said:
I think two angles are enough for planes and ships, why 3?
No, you need 3 axis on planes and ships; telescopes, dishes and solar panels don't need roll, so they only have 2.
 
  • Like
Likes sysprog and FactChecker
  • #5
phinds said:
Uh ... you think planes can only move in 2 dimensions?
It's not about moving it's about orientation: 2 axes of orientation is enough to move in 3 dimensions (1 axis for 2 dimensions). You need the 3rd in vehicles just to stay level(roll).
 
  • Like
Likes sysprog
  • #6
marcusl said:
They don't describe movement so much as attitude, which is the physical orientation of an object relative to some reference coordinate system.
This is true but can be confusing when it comes to pitch, which is used interchangeably at least in shorthand "pitch" or "pitch attitude".
 
  • #7
russ_watters said:
It's not about moving it's about orientation: 2 axes of orientation is enough to move in 3 dimensions (1 axis for 2 dimensions). You need the 3rd in vehicles just to stay level(roll).
egg_small.jpg
 
  • Like
Likes sysprog and jim mcnamara
  • #8
I sell coordinate measurement machines. These cnc machine tools move in cartesian or polar coordinates. Cartesian system of coordinates use is the X,Y and Z axis where points are describes by x,y and z locations. Polar coordinates describe the location by a distance and azimuth or direction ( usually in degrees from an origin or datum) Elevation describes a location relative to height. ( usually AGL or above ground level or normal to the 0 plane of the X,Y axis along the Z axis.Great video on roll yaw and pitch.
 
  • Like
Likes sysprog, jim mcnamara, berkeman and 1 other person
  • #9
Notice that "roll" does not seem to have a meaning for an antenna, except that when we rotate the plane of polarisation we are executing roll.
It is also common to use the terms pan and tilt, as with photography.
 
  • Like
Likes suremarc
  • #10
One dish antenna system has specs of azimuth and elevation. In addition it also has a roll range. As far as I understand azimuth and elevation are in principle enough for pointing to a direction. With the additional roll it could rotate more quickly. Is it correct?

Owen
 
  • #11
I imagine the "roll" movement is for adjustment of polarisation, but it is more usual to do this by rotating the feed.
 
  • Like
Likes russ_watters and Klystron
  • #12
tech99 said:
I imagine the "roll" movement is for adjustment of polarisation, but it is more usual to do this by rotating the feed.

The person in this video rotates the feed manually. [Warning: the tech in this video should remove his ring and watch while working on electronics.]
 
Last edited:
  • #13
in the " old days" you had one satellite in orbit and elavation and azimuth were enough to align the dish. now you have 3 satellites and you need to ROLL or tilt the dish to get the best possible signal.
 
  • Like
Likes sysprog
  • #14
Why is this?
 
  • Like
Likes davenn
  • #15
from wikipedia
It is common to polarize satellite TV signals because it provides a way of transmitting more TV channels using a given block of frequencies. This approach requires the use of receiving equipment that can filter incoming signals based on their polarisation. Two satellite TV signals can then be transmitted on the same frequency (or, more usually, closely spaced frequencies) and provided that they are polarized differently, the receiving equipment can still separate them and display whichever one is currently required.

Throughout the world, most satellite TV transmissions use vertical and horizontal linear polarization but in North America, DBS transmissions use left and right hand circular polarization. Within the waveguide of a North American DBS LNB a slab of dielectric material is used to convert left and right circular polarized signals to vertical and horizontal linear polarized signals so the converted signals can be treated the same.

A 1980s Ku-band LNB (2.18 dB noise figure) without built-in polarization selection and with a WR75 fitting for separate feedhorn and polarizer

The probe inside the LNB waveguide collects signals that are polarized in the same plane as the probe. To maximise the strength of the wanted signals (and to minimise reception of unwanted signals of the opposite polarization), the probe is aligned with the polarization of the incoming signals. This is most simply achieved by adjusting the LNB's skew; its rotation about the waveguide axis. To remotely select between the two polarizations, and to compensate for inaccuracies of the skew angle, it used to be common to fit a polarizer in front of the LNB's waveguide mouth. This either rotates the incoming signal with an electromagnet around the waveguide (a magnetic polarizer) or rotates an intermediate probe within the waveguide using a servo motor (a mechanical polarizer) but such adjustable skew polarizers are rarely used today.

The simplification of antenna design that accompanied the first Astra DTH broadcast satellites in Europe to produce the LNBF extended to a simpler approach to the selection between vertical and horizontal polarized signals too. Astra type LNBFs incorporate two probes in the waveguide, at right angles to one another so that, once the LNB has been skewed in its mount to match the local polarization angle, one probe collects horizontal signals and the other vertical, and an electronic switch (controlled by the voltage of the LNB's power supply from the receiver: 13 V for vertical and 18 V for horizontal) determines which polarization is passed on through the LNB for amplification and block-down conversion.

Such LNBs can receive all the transmissions from a satellite with no moving parts and with just one cable connected to the receiver, and have since become the most common type of LNB produced.

The final alignment that needs to be set is the skew adjustment on the LNB. This is the angle that the LNB itself sits within the LNB holder. Unless the satellites that you wish to align your dish to are perfectly due south (or north down under!) then you are going to need to make an adjustment for the LNB skew. The reason this is so important is because satellite signals are broadcast in both horizontal and vertical polarisations and without setting the skew correctly the LNB and satellite dish will not be able to optimally identify the difference between these and they can interfere with one and another resulting in an unreliable signal, picture pixilation and possible complete loss of signal altogether.

in other words you got to tilt it in for the best signal.
 
  • Informative
Likes Klystron
  • #16
Thank you, I had forgotten linear polarisation is used in some cases, I thought it was all circular. Memory problem!
 
  • #17
In reality the additional roll axis is introduced to mitigate the so called overhead keyhole effect. Is this a conventional method?
 

1. What are yaw, pitch, and roll?

Yaw, pitch, and roll are three rotational movements used to describe the orientation of an object in three-dimensional space. Yaw is the rotation around the vertical axis, pitch is the rotation around the horizontal axis, and roll is the rotation around the longitudinal axis.

2. How are yaw, pitch, and roll different from azimuth and elevation?

Yaw, pitch, and roll are used to describe the orientation of an object relative to its own axes, while azimuth and elevation are used to describe the orientation of an object relative to a fixed reference point, usually the horizon. Yaw, pitch, and roll are also known as intrinsic rotations, while azimuth and elevation are known as extrinsic rotations.

3. What is the relationship between yaw, pitch, and roll and azimuth and elevation?

Yaw, pitch, and roll can be converted to azimuth and elevation and vice versa, but they represent different ways of describing the same orientation. The conversion between the two depends on the coordinate system being used.

4. What are some applications of yaw, pitch, and roll and azimuth and elevation?

Yaw, pitch, and roll are commonly used in aviation and aerospace industries to describe the orientation of aircraft and spacecraft. Azimuth and elevation are used in astronomy and navigation to locate objects in the sky. Both systems are also used in virtual reality and video games to track the movement of objects.

5. Can yaw, pitch, and roll and azimuth and elevation be used interchangeably?

No, yaw, pitch, and roll and azimuth and elevation are not interchangeable as they represent different ways of describing orientation. However, they can be converted to each other depending on the specific application and coordinate system being used.

Similar threads

  • Classical Physics
Replies
1
Views
743
Replies
1
Views
490
  • Aerospace Engineering
Replies
8
Views
2K
Replies
2
Views
3K
  • General Engineering
Replies
2
Views
2K
  • Mechanical Engineering
Replies
11
Views
2K
Replies
24
Views
2K
  • Other Physics Topics
Replies
4
Views
4K
Replies
1
Views
729
Replies
3
Views
2K
Back
Top