Virtual Flight Testing of Radar System Performance
Flight testing is the primary method for evaluating the performance of a radar system. While an aircraft is in flight, data such as probability of detection, signal strength, and clutter might be gathered. Though effective, this approach does pose a number of testing challenges. The following explores the use of virtual flight simulation in the interest of saving time and money, while also increasing accuracy.
Challenges of Flight Testing:
- In order to obtain statistically significant results, a large number of flights must be performed in order to yield an adequate data sample. The costs incurred in hands-on flight testing are thus sizeable. This method is simply too cost-prohibitive.
- The data and test conditions from one flight run to the next are not repeatable, resulting in the need for multiple runs, and thus more money. Without the ability to easily replicate results, the time involved in the test environment is increased.
A Potential Solution:While in-field operational verification may still be necessary for contractual or legal reasons, “virtual flight testing” is a faster, more cost-effective alternative for earlier stages of R&D. The ability to simulate the full deployment and flight environment enables exceptional development speed and provides rapid prototyping capabilities of any radar system environment. With lessened time and money involved, simulation poses a viable solution to the testing challenge.In simulation:
- Complex radar systems can be evaluated hundreds of times in an hour (Using the same/different scenarios for each run).
- By evaluating realistic flight-testing scenarios before or in place of physical flight testing, engineers can validate electronic warfare algorithms earlier, saving both time and money.
The Virtual flight test solution was created by combining the capabilities of Keysight SystemVue software with those of the AGI STK tool from Analytical Graphics. The W1461BP SystemVue Comms Architect is electronic system-level design software that integrates modeling, simulation, reference IP, hardware generation, and measurement links into a single, versatile platform. It enables system architects and algorithm developers to innovate the physical layer (PHY) of wireless and aerospace/ defense radar and communications systems, and provides unique value to RF, DSP, and FPGA/ASIC implementers. The W1905 Radar model library provides baseband signal processing reference models for a variety of radar architectures.
Figure 1: Interface between SystemVue and Analytical Graphics (AGI) STK product for multiple-target signal emulation.
As shown in Figure 1, one application of the interface between SystemVue and STK is the ability to do virtual flight testing of a radar system, including DSP, RF impairments, jamming, and interference as an aircraft encounters targets and clutter along a virtual flight plan.
To gain a stronger understanding of the interface between SystemVue and STK, and their application to virtual flight testing, consider the 3D STK simulation scenario of a fighter sortier (Figure 1). It starts at 10,000ft and is detected by the radar. It spot dives down to do low-level terrain following in order to get below the radar- sometimes successfully, sometimes not. This scenario can be reconstructed hundreds of times, with different radar or electronic countermeasure assets in place, by implementing SystemVue. The terrain, aircraft (including 3D RCS), and the radar site characteristics may all be easily modeled and analyzed.
Figure 2: Multiple-Target Signal Emulation Example
In the multiple-target signal emulation example, shown in Figure 2, test entry data is entered through a customer user interface with full customization capabilities. The user does not have to open a simulation schematic. This approach integrates both signal generation and signal analysis. Here, SystemVue creates a radar waveform and passes it through a transmit chain to multiple target models (including jamming and added clutter). The resultant RF waveform can then be input into an arbitrary waveform generator and introduced into a receiver for performance validation. SystemVue also has a tight integration with MATLAB, C++, and HDL simulators, so existing radar algorithms may also be integrated into the scenario. Measurement-based data, such as a jammer profile or measured interference, could also be added into the simulation directly through Keysight test equipment links.
These scenarios can be evaluated in lieu of physical flight testing or, in cases where operational flight testing is unavoidable, they can be evaluated beforehand to ensure they make the most effective use of resources.
Some applications of virtual testing include:
- Evaluating new jamming techniques or threats
- Injecting multiple dynamic emitters and targets into scenarios
- Allowing various types of jamming based on a defined set of criteria for dynamic operation
- Modeling and evaluating cross-domain effects, such as automatic gain control
Virtual flight testing, made possible by the flexible interfaces between the SystemVue and STK software tools, now offers an economical alternative for R&D validation. This allows measurement-hardened algorithms to be deployed quickly, and any required field-testing to be performed with greater confidence. By moving testing into the lab and away from the field, time and money are spared, while measurement accuracy is improved.