Radar Design with the Radar Designer App
The Radar Designer app is an interactive tool that assists engineers and system analysts with high-level design and assessment of radar systems at the early stage of radar development. Using the Radar Designer app, you can:
- Assess and compare multiple radar designs in a single session
- Add smart radar, environment, and target radar designer configurations to jump-start your analysis
- Incorporate environmental effects due to the Earth's curvature, atmosphere, terrain, and precipitation
- Add custom target radar cross-sections, antenna/array models, and both range-independent and range-dependent losses
- Export and save results, sessions, models, and plots to continue your analysis
Published: 1 Nov 2021
Radar systems development is complex, with many interconnected parameters and requirements. The analytical models, for hardware and software components, of these systems, can be difficult to organize, and explore. The Radar Designer app provides an easy to use interface, for parameter input design comparison visualizations, and sharing of results.
Let's walk through using the app for an airport radar design. We're going to design and expand surveillance radar, for detecting small targets. The radar should detect small manned aircraft, up to 18 kilometers. small, unmanned aircraft up to eight kilometers. And maintain performance, in heavy rain. On the left hand side of the app, we have the input parameters for the radar target, and environment. On the right hand side, we have visualizations of the system, and a table to compare the metrics to requirements.
We'll start by adjusting the Max Range Constraint. Then input our threshold, and objective requirements. The desired performance of the system is defined by the objective requirement. But the system is considered to have an acceptable performance if threshold is met. The manned aircraft is a swirling one target with radar cross section of one meter squared. Now we can set our radar parameters. The frequency and peak power are set to values in the design specification. And the pulse bandwidth is adjusted, to meet the range resolution requirements. And the pulse width is set to achieve high enough available SNR, at the maximum range.
The azimuth and elevation antenna beam width are set to two and six degrees, respectively, to meet the azimuth and elevation accuracy requirements. Scan mode is set to mechanical, to give 360 degree coverage and azimuth. Including scanning in the analysis adds the beam shape loss, and beam dwell factor, to the link budget.
The number of coherently integrated pulses is selected, to satisfy the objective detectability, with the swirling one case target, and one e minus six probability of false alarm. We account for losses, due to pulse eclipsing, and add this to the budget analysis. After these adjustments, the Metrics and Requirements table shows that this design satisfies the specification for small manned aircraft, with RCS of one meter squared, or larger.
The specification states that the radar under design must maintain the required detection performance, and the measurement accuracy, in heavy rain. To include the path loss due to precipitation, in the analysis, we set precipitation type to Rain, in the precipitation section of the environment panel. We then choose the ITU model, and set the ranges, such that 16 millimeter an hour range is present in all ranges of interest. Now, the metrics and requirements table, and the SNR verse range plot, show that the probability of detection, at the maximum range, is much lower than the required 0.9.
We'll have to make adjustments to the design. So let's make a duplicate of this design, just to compare the performance, before and after. The probability of detection can be improved by either increasing the SNR available at the receiver, or by decreasing the SNR required to make a detection. The latter approach might be more attractive in practice, since decreasing the detectability factor can be accomplished through signal processing techniques, that do not require making changes in the hardware. The detectability factor can be decreased, by integrating more pulses. However, target RCS fluctuation usually imposes a limit on the amount of pulses that can be coherently integrated. A possible solution to integrating more pulses, while addressing the problem of the arcs fluctuation, is the aim of an integration, over multiple coherent processing intervals.
Navigating to the Radar panel, and setting the number of CPIs in the detection, and tracking section to three, and the number of CPIs with the detection to two, increases the resulting probability of detection. Although the probability of detection is still below the specified objective value, it meets the threshold requirement. This means that the system has an acceptable detection performance, in heavy rain. Similarly, the range azimuth and elevation accuracies clear the threshold requirement, but are below the respective objective values.
To verify this radar design will have satisfactory performance, when the target is a small UAS, we can change the target RCS, and maximum range constraint. The SNR versus range plot shows that the available sensor for this design is above the objective detectability line, at eight kilometers.
We successfully designed a radar that can meet our requirements. We can share these results by automatically generating Matlab scripts, that recreate the plots, and requirements, and metrics table. These results can be shared, and opened, in spreadsheet software. For more information on our radar design capabilities, please visit our documentation.