Key Interoperability Technologies

Differences between HLA 1.3 and HLA 1516

This page describes the differences in HLA (High-Level Architecture) between version 1.3 and the IEEE version called HLA 1516. HLA is a standard for connecting different simulations systems, read more on "What is HLA".

Overview

HLA IEEE 1516 is the successor of HLA 1.3. HLA was developed as a US DoD IEEE. This would facilitate a broader adoption internationally as well as in all types of cmmercial industries. The overall goals of the new version were to further improve it and to add support for common industry standards such as XML and Unicode (international character sets).

HLA 1516 was standardized through IEEE in 2000 and the first full implementation was available late 2001. There is a verification process run by the US DoD that performs about 2000 tests to verify that an RTI meets the specification. Today HLA users all over the world are adapting the new standard. (Department of Defence) standard in several steps up to version 1.3. When the new version was developed it was decided to make it an open international standard through

The HLA 1516 standard undergoes continuous development. The next main revision of the standard has the working name "HLA Evolved" and is expected to be finalized during 2007. 

Differences

The main technical improvements in the HLA 1516-2000 standard are:

1. The 1516 standard solves a number of problems found during practical use of HLA 1.3. It is also more strictly defined.

2. The behaviour of many functions is more logical. Example: You subscribe to the x and y position of an airplane and then subscribe to the z position. In HLA 1516 the new subscription will be added to the earlier one instead of replacing it.

3. Filtering of information (with Data Distribution Management) is easier and more flexible. You may freely decide which dimensions to use for filtering at runtime.

4. Some additions allow for better performance and scalability. For example in simulations with many objects it is possible to pre-register object names before the main simulation starts. When you later want to create the objects this is a fast operation.

5. The documentation of the object model is more complete. This leaves less room for confusion in the project and speeds up integration.

6. The object model now uses industry standard XML format. This opens more possibilities for example to process the XML in standard tools and to do your own code or scenario generation etc.

7. The object models use Unicode character representation instead of ASCII. This is better for international use since virtually any language can be used.

The full HLA 1516 specification is available at IEEE. If you want to try out a full and certified implementation of HLA 1516 with both C++ and Java APIs, download the pRTI 1516 Limited Edition.