ATX File

What are ATX files and how to open them

Are you having problems opening an ATX file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your ATX files.

What is an ATX file?

ATX files have multiple uses, and ANTEX Antenna Exchange Format is one of them. Read more about the other uses further down the page.

ANTEX Antenna Exchange Format

IGS models use the ATX file format to store data about satellites and antennas. The data consists of satellite codes, GPS locations, serial numbers, system flags, slot numbers, and a few more. IGS is working on a set of absolute antenna phase center corrections for the antenna receiver networks and the satellites, which we find in the ATX files.

How to open ATX files

Important: Different programs may use files with the ATX file extension for different purposes, so unless you are sure which format your ATX file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested six different ATX openers which you will find listed below.

Last updated: August 22, 2026

All known file formats using extension .ATX

While ANTEX Antenna Exchange Format is a popular type of ATX-file, we know of 3 different uses of the .ATX file extension. Different software may use files with the same extension for different types of data.

Apple IOS Texture

Apple iOS Texture files are Apple's own texture‐container format used within iOS to store images prepared for onscreen display. They wrap compressed texture data (especially ASTC) together with metadata about size, pixel format, and layout, and are used in places like system UI image caches, snapshots, wallpapers, avatars, and so on. These files are not raw photos or user‐managed assets but intermediate textures optimized for Apple's graphics pipeline.

They are produced by Apple software components in the operating system or by Apple's internal tools; they are not typically authored directly by third‐party applications. Tools that inspect iOS system files or do forensic work can decode them into standard RGBA images for viewing. The decoding involves reading metadata describing compression type (for example raw or compressed ASTC, sometimes with LZFSE compression), un‐tiling if needed, decompressing, and outputting linear RGBA8 data.

Every file of this type begins with an 8-byte signature consisting of the ASCII letters "AAPL" followed by the PNG-style guard bytes (carriage return, line feed, 0x1A, line feed). After that comes a sequence of chunks each with a length, a FourCC tag, then a payload. Tags used include HEAD for metadata chunks, ASTC (or astc) for raw ASTC texture data, LZFS for LZFSE‐compressed ASTC payloads, and FILL. The tag and size fields are part of a chunk header immediately following the signature.

VAPI/ATX Atari 8-bit Disk Image

VAPI/ATX is a disk image format developed to preserve Atari 8-bit floppy disks exactly, including any custom formatting or copy-protection. These images replicate not just file contents but also low-level disk structure, enabling emulation or usage with hardware like SIO2PC, APE, or SIO2Arduino. Support for VAPI/ATX allows reading or booting of protected disks that simpler image formats can't preserve.

The format was created by Jorge Cwik (known as ijor) as part of the VAPI project. For single-density disks it behaves as a superset of the ATR image format; the ATX image format adds structures to represent tracks, sectors and errors exactly. It includes optional extended sector data that records things such as weak bits, deleted sectors, missing sectors, and CRC or lost-data errors. The format is divided into a file header, then a sequence of track records, each containing headers, sector lists, sector data, and optional bracketed data for sectors marked special.

Images begin with a specific header: the ASCII signature spelled out as A T 8 X ('AT8X') in bytes at offset zero.

Various apps that use files with this extension

These apps are known to open certain types of ATX files. Remember, different programs may use ATX files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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