Where to find Azimuth Angle

[Teracotta]

Hello,

I would like to ask where to find Azimuth angle fo Sentinel-1. I was looking to Metadata and there is only the Incidence angle range (Incidence near and Incidence far). Do you know? please!

[Hrishikesh]

Hi @Teracotta,

If you meant Azimuth direction or heading of Sentinel -1 then this will help you -

Satellite Azimuth Direction/Heading

Heading, azimuth direction, of the Sentinel-1 product is provided in metadata as “platformHeading”. It is explained in Sentinel-1 Product Specification as follows Table 6-31 Data Type – productInformationType platformHeading: Platform heading relative to North [degrees]. Example from SNAP [image] Is this information what you are looking for?

It is with respect to North direction. Clockwise is positive and anti-clockswise is negative.

[ghajduch]

The link to the product specification provided above is broken.
The latest version of the product specification can be found in the SAR document librabry in Sentinel Online here:
https://sentinel.esa.int/nl/web/sentinel/user-guides/sentinel-1-sar/document-library

Be careful with the meaning of platform heading. This refer to the platform heading, and not to the azimuth directions of points in the image. Both are different, especially at high latitudes.

[mengdahl]

@ghajduch

Be careful with the meaning of platform heading. This refer to the platform heading, and not to the azimuth directions of points in the image. Both are different, especially at high latitudes.

This detail is not clear to me, is there a more comprehensive definition of platform heading available somewhere? Is the angle-difference you mention above caused by Earth rotation or something else?

[ghajduch]

Hi @mengdahl

The “platform heading” should be by definition the direction toward north of the platform. The point is that the azimuth direction within the product is not equal to the platform heading and is not constant. This is because a product is 2-dimensional + it is not on the nadir + the Earth is not flat.

I pushed an illustration of this here:

How to obtain the azimuth looking angle in sentinel 1 images through SNAP?

Hello, you can find it in the footprint tag. In my file it is at line 219-221. [image] The related documentation is in the Sentinel-1 Product Specification in Table 6-7 page 93. But you might want to look at these threads too: Where to find Azimuth Angle - s1tbx - STEP Forum (esa.int) Azimuth angle - s1tbx - STEP Forum (esa.int)