The growth and advancement in automotive radar has led to several challenges for the test and validation of radar sensors. The first set of challenges center on meeting the increasing technical requirements for testing modern automotive radar while maintaining or lowering the cost of production test. It is typical for a modern radar sensor to require 1 GHz of bandwidth at 76-77GHz, and few companies have the expertise to build test systems in this frequency band. Higher bandwidth sensors provide finer resolution, and radar manufacturers have already demonstrated sensors with higher bandwidths approaching 4 GHz with a 79 GHz center frequency.
While the technology in radar sensors continues to improve, in order to enable the broad adoption of radar sensor and meet the price and volume requirements, manufacturers need to reduce testing costs and time.
Early radar sensor manufacturers used large anechoic RF chambers and corner reflectors to functionally test and calibrate modules. These chambers were commonly several meters long and consumed large amounts of manufacturing floor space. To reduce floor space, radar functional testing evolved to use analogue delay lines to emulate long-distance radar obstacles followed by a second test station to perform parametric measurements of the radar.
Technology for radar functional testing has further evolved, as showcased by the NI Vehicle Radar Test System (VRTS). The VRTS is a hybrid simulator built around the NI PXIe-5840 Vector Signal Transceiver (VST), which integrates an instrument-quality RF Vector Signal Analyzer with a RF Vector Signal Generator via a high-performance, low-latency Xilinx FPGA. The FPGA can calculate radar reflection signatures in incredibly short periods, allowing the RF Vector Signal Generator to generate a corresponding radar signal back to the radar sensor. This approach can consolidate a radar module production test cell by combining the functional test (object simulation) and the parametric tests into a single tester. The combination reduces manufacturing floor footprint dramatically and eliminates the overhead of transferring radar modules between test stations, improving throughput and freeing up space for additional testers.