MIMO Radar System Test Tools and Techniques

Modern technologies such as multiple-input multiple-output (MIMO) require wide bandwidth, phase consistency, and multi-channel analysis. The antenna elements in a MIMO radar system operate independently and cover a wide (typically 180-degree) field of view without the need for directional adjustments . As a result, scan times are significantly reduced. MIMO radar uses time, frequency or coding techniques to distinguish each transmitted signal in the receiver element to extract target attributes. 

A wideband oscilloscope, such as the Tektronix DPO70000SX or MSO/DPO70000DX Series oscilloscopes, is designed for wide bandwidth and phase consistency, making it an ideal instrument. It supports independent settings of parameters such as center frequency, spectrum width and resolution bandwidth (RBW). When used in conjunction with the SignalVu VSA 5.3 software version for multi-channel control and analysis, the resulting test system is an excellent test system for validating MIMO phased array radars. choose. Independent settings are necessary for acquiring signals that may have different center frequencies, time slots or modulation parameters. 

Pulse statistics for spectrum analysis

TDM MIMO radar assigns a time slot to each element. For each channel signal, the pulse width is 1 microsecond, the pulse repetition interval (PRI) is 100 microseconds, and the time slot delay between channel 1 and channel 2 is 10 microseconds. With SignalVu software we can see if the generated signal is properly aligned with the specified time slot. We can use SignalVu's time overview display to configure the analysis time and spectrum time parameters and then examine the start position or start time of the pulse on each channel to determine the time delay between channels. Additionally, we can measure the PRI of both channels to determine if the latency remains the same throughout. The pulse statistics display allows us to observe time trends and measurement statistics to understand how the PRI of each pulse changes over time. Pulse tables provide information about the absolute delay between channels or time slots, while time trends show how this delay maintains over time.

Vector signal analysis using SignalVu VSA v.5.3 software version

Frequency and timing of using FastFrameTM segmented memory 

To gain a complete understanding, we need to analyze many pulses, but the oscilloscope's record length determines how long the signal can be captured. In SignalVu's FastFrame mode, this is not a significant limitation. Applying FastFrame mode, we can capture only the pulse on time and ignore the pulse off time. This innovative approach greatly improves the analysis of hundreds of pulses without compromising the quality of the analysis. It divides the memory into smaller segments and fills these segments with only on-time data while retaining time scale information. To improve signal visualization in FastFrame mode, Pulse Plot displays a waterfall plot of multiple segmented captured pulse signals, containing the associated amplitude versus time and spectrum for each pulse signal. This mode can be used with an external trigger to display target range and speed.

FastFrame mode for pulse analysis

Orthogonal signals require independent control 

The combination of automatic pulse measurement and FastFrame segmented memory capture, together with independent control, allows us to analyze complex scenarios such as MIMO radar. Using SignalVu software, we can perform pulse analysis on multiple channels simultaneously. The advanced pulse analysis package provides up to 31 measurement parameters to automatically characterize pulse sequences. MIMO radar's signals are orthogonal so that a different center frequency is applied to each element. Therefore, the center frequency as well as the spectrum width and RBW of each channel in SignalVu are configured independently. This feature enables us to use SignalVu to efficiently analyze wide-bandwidth, multi-channel phase-synchronized systems operating at different frequencies. Multi-channel broadband analytics solutions include fully configurable and customizable controls so you can handle even the most complex scenarios.