This document describes the communications protocol associated with the LSTS software framework. Concepts such as message, field and packet are explained in detail in the subsequent chapters.
Inter module communication is achieved by the exchange of messages that can be recognized and interpreted by all participating modules. A message is a self-contained collection of data fields conveying relevant information about a given subject. The mean by which the messages are exchanged is not described in this document, but the reader can assume that at least the UDP Internet protocol is available at all ends of the communications channel.
The Neptus Command and Control Unit (CCU), currently being used at LSTS, supports mission planning and control, using the described messaging API. This software entity can be used to define a plan before execution and monitor the plan’s execution by presenting an operating console. For further details on this software contact the LSTS.
A CCU exercises authority over a vehicle (real or simulated). Usually this term is applied to software in the class of LSTS Neptus, but can also be applied to software modules extending the vehicle core control software.
The LSTS reserves itself the right to use message identification numbers up to 999. Thus if a third party needs to extend this API it must use identification numbers starting at 1000. The identification number 65535 has a special meaning and must not be used to extend the IMC protocol.