16.- Usability

It refers to the degree to which a software can be used by specified consumers to achieve quantified objectives with effectiveness, efficiency, and satisfaction in a quantified context of use.

Indicators of Usability

It follows a list of possible usability indicators for a software-defined GNSS receiver:

Availability of a (versioned) User Manual.
Availability of a (versioned and documented) application programming interface (API).
Availability of graphical user interface.
Availability of accessibility mechanisms for users who experience disabilities.
Availability of mechanisms for remote operation.
Availability of interfaces with other programming languages.
Availability of user documentation: tutorials, detailed howtos, user stories, etc.

For the project, product, or service in which the software receiver has a role:

Website of project, product, or service.
Availability of professional help desk support services.
Availability of communication channels with other users and the development team.
- Public mailing list.
- Presence in public IRC channels.
- Presence in social networks.

For the computing platform executing the software receiver:

For physical devices:
- Computer form factor, shape, size, and weight.
- Power consumption / battery autonomy.
- Degrees of protection from solid objects and liquids, given by the Ingress Protection rating system. Examples:
  - IP65: protection from dust and from low-pressure jets of water in all directions. Limited water ingress permitted.
  - IP67: protection from dust and against the effects of immersion in water to depth between 15 cm and 1 meter.
- Temperature / humidity / vibration operative ranges.
For cloud-based services:
- Input/output data throughput requirements.
- Computational and memory bandwidth requirements.
- Connection to third parties in case of assisted or differential GNSS.