The satellite or the aeroplane on which the remote sensor is fixed is called Platform
Definition - What does Platform mean?
A platform is a group of technologies that are used as a base upon which other applications, processes or technologies are developed.
In personal computing, a platform is the basic hardware (computer) and software (operating system) on which software applications can be run. Computers use specific central processing units (CPUs) that are designed to run specific machine language code. In order for the computer to run software applications, the applications must be in that CPU’s binary-coded machine language. Thus, historically, application programs written for one platform would not work on a different platform.
Techopedia explains Platform
A computer platform generally refers to the operating system and computer hardware only. The platform conforms to a set of standards that enable software developers to develop software applications for the platform. These same standards allow owners and managers to purchase appropriate applications and hardware. Thus, to run a bookkeeping program on a computer, one must purchase a bookkeeping software application that was developed for the platform on which it will be used.
New standards-based interfaces and open interfaces allow application programs to run on multiple platforms. Additionally, software developers have developed software tools that allow applications to run on multiple platforms. This has given rise to the terms cross-platform software and multi-platform software.
Newer web browsers allow third-party plug-ins to be run as part of the browser. Therefore some browsers are now spoken of as platforms since they are used as a base on which to run other applications' software programs.
An example of a computing platform is a modern laptop running Windows as an operating system. Another example would be an Apple computer running the Mac OS X operating system.