Land Open Systems Architecture (LOSA): UK MOD guidance for interoperable land systems

# What LOSA is

Land Open Systems Architecture (LOSA) is the UK Ministry of Defence's guidance for designing land capabilities so they can share data and integrate with each other more easily. It relies on open standards, common data models and defined interfaces to give systems a shared way to exchange information with consistent meaning.

LOSA is aimed at programmes, MOD delivery teams, suppliers and systems integrators who design, procure, develop or integrate defence capability. It is focused on the land environment but its principles can support wider defence integration where common data models and defined interfaces are needed.

# The core components

LOSA is supported by several core products that structure how data and interfaces are defined:

• Land Data Model (LDM): the parent data model that provides the baseline data definitions.

• Generic Base Architecture (GBA): approaches for base infrastructure and fixed or deployable facilities.

These components are intended to be used together so systems built for different purposes still map to a shared model.

# What LOSA changes about integration

Traditional integration often uses bespoke point-to-point interfaces created for each project. LOSA replaces that pattern with:

• Common data definitions that give shared meaning to exchanged information.
• Standardised interfaces and reusable integration patterns.

The practical effects are fewer custom adapters, simpler system upgrades, and lower ongoing integration effort across programmes and suppliers.

# Where to apply LOSA

Use LOSA when you are working on systems or equipment that need to exchange data with other MOD systems, allied systems, or industry partners. Typical areas include vehicles, soldier systems, sensors, communications equipment, command-and-control applications, software services, and infrastructure.

LOSA is most relevant when systems must operate together, share information consistently, or remain adaptable as technology changes.

# Why LOSA matters for procurement and capability managers

• Reduces vendor lock-in by making it easier to replace components without redoing the whole integration.
• Lowers cost and time required for bespoke integration work.
• Enables a broader supplier base to produce compatible components aligned to the common models.

It aligns with wider MOD objectives, such as encouraging competition and interoperability across defence programmes.

# International and coalition use

The LDM and LOSA approach are used to support interoperability with NATO members. By providing a consistent way to describe, structure and exchange data, LOSA reduces bespoke work required between national systems and helps UK platforms operate alongside allied platforms in coalition operations, joint experiments and multinational capability development.

# Practical next steps for delivery teams

• Refer to the LOSA documentation and the LDM when defining data requirements for new projects.
• Map proposed system data elements to the LDM to identify reuse opportunities.
• Use GVA/GSA/GBA patterns where applicable to reduce bespoke interface design.
• Specify open standards and defined interfaces in procurement documents to enforce LOSA alignment.

Adopting LOSA is a design and acquisition decision: it requires specifying common models and interfaces early so downstream development and procurement follow the same integration patterns.