Communications links operating in airborne and aerospace environments must overcome the stress of high velocity and acceleration in addition to the usual challenges of interference and fading. Fortunately, the EB Propsim C8 propagation simulator from Elektrobit Corp., when equipped with the firm's ASO tool, can create the complex signal conditions needed to emulate communications channels in aerospace and airborne scenarios. The simulator operates from 350 MHz to 6 GHz with channel bandwidths to 70 MHz.

The EB Propsim C8 simulator system was initially developed for performance verification and testing of multipleinput, multiple-output (MIMO) communications systems, such as WiMAX, TD-SCDMA, IEEE 802.11n, and Long Term Evolution (LTE) emerging cellular standards, as well as for proprietary wireless communications systems. It is in this latter applications area that the system has been enhanced with the the firm's ASO software to provide test capabilities for special wireless communications environments, such as satellite and spacecraft communications, aircraft and helicopter communications, and even guided missile communications. In each of these cases, the communications link is subject to high velocity and acceleration. The EB Propsim C8 with ASO software can emulate those complex propagation conditions faced by airborne communications systems.

The EB Propsim C8 simulation system with ASO software works with external RF signals over a range of -30 to 0 dBm and provides RF output signal levels with 0.1-dB resolution. The system can also be provided with an optional local oscillator (LO) for internal generation of RF signals. The system is designed to provide signal emulations at RF or baseband frequencies, and can control all of the signal parameters, such as fading attenuation, Doppler shifts, and velocity and acceleration effects, that might be experienced by communications systems in space-based systems, air-to-air, air-to-ground, and ground-to-air systems. The system provides an adjustable propagation delay range of as much as 6.4 ms (see table), and can control path delays with 0.1-ns resolution and 1-ns accuracy.

In terms of velocity and accuracy, the simulator can emulate the effects of range rates to 20 km/s and acceleration to 50 g's. In terms of fading, the system offers pure Doppler profiles across a relative path fade attenuation range of 0 to 60 dB. The EB Propsim C8 with ASO simulator also features adjustable channel gain of 0 to 75 dB. Doppler shifts can be adjusted at rates to 1.25 MHz with resolution of 0.3 MHz.

The EB Propsim C8 with ASO is available with optional internal interference generator capable of producing CW or additive white Gaussian noise (AWGN) interference. Noise can be added at densities from -150 to -100 dBm/Hz with 13-dB crest factors. The simulator has an embedded personal computer (PC) for control and programming. Elektrobit Corp., Tutkijantie 8, FIN-90570 Oulu, Finland; +358 40 344 2000, FAX: +358 8 570 1301, Internet: www.elektrobit.com.