Navigation & Communication

The F-14’s primary navigation system is a multi-unit Carrier Aircraft Inertial Navigation System (CAINS) designated as AN/ASN-92. An INS system measures and integrates sensed inertia forces (acceleration) and rotational velocities to calculate aircraft position and linear velocity. A good navigation system can precisely guide an aircraft on a route to a mission objective hundreds or thousands of miles long, and then back to the home base, safely and reliably. Such a system is even more important when an aircraft is designed to operate over the ocean, far away from any ground-based TACAN or visual references.

Designing an INS (IMU) is an engineering challenge, which requires consideration of such problems as calibration, alignment, Earth’s rotational motion, inertia forces, thermal stability, analogue-digital converters precision, all different types of corrections which have to be applied to keep the device precise over extended time, and many more. Simulating an INS platform is very similar - it is a complex undertaking.

At Heatblur, we decided to develop an entirely new mathematical model to simulate the AN/ASN-92 for our F-14. We included all the potential sources of errors contributing to the final precision of the device, and recreated the characteristic behavior of a gimballed INS platform. The result is a set of algorithms providing an authentic representation of the AN/ASN-92 in DCS, yet optimized to have almost no impact on CPU performance.

The main components of the INS are the inertial measurement unit (IMU), the power supply unit, and pilot and RIO navigation controls and displays.

Although from the crew member’s point of view, the INS is used mostly for navigation, it is also essential for proper operations of other aircraft equipment. For example, the attitude is necessary for the radar. The attitude and the own position are required for some weapon delivery modes, particularly for long shots. Even more distressing to the crew, a complete failure of the INS renders the more advanced modes of weapons such as the AIM-7 and AIM-54 missiles inoperable.

The same information is used for data-link operations - when using erroneous INS data, own tracks and targets received from cooperating aircraft will not match and result in false contacts being displayed on the TID. These are only a few examples, and the INS data is used whenever aircraft position or attitude is required.

Thus, the inertial navigation system (INS) integrates with the AWG-9 computer (WCS computer) and the CSDC, the computer signal data converter. Other related equipment includes the attitude and heading reference system, central air data computer, radar altimeter, instrument landing system, and TACAN.