That's a very common perception, but it's not true! Kalman filters have for years been used to get usable data out of these and multiple studies have shown that

That's a very common perception, but it's not true! Kalman filters have for years been used to get usable data out of these and multiple studies have shown that ultrasound can be used as a standalone in low-speed scenarios. Design and experimental study of an ultrasonic sensor system for lateral collision avoidance at low speeds - https://ieeexplore.ieee.org/abstract/document/1336460 https://ieeexplore.ieee.org/abstract/document/1336460 Environmental perception and multi-sensor data fusion for off-road autonomous vehicles - https://ieeexplore.ieee.org/abstract/document/1520113 https://ieeexplore.ieee.org/abstract/document/1520113 (this one uses laser range finders not LIDAR with some vision) "Automotive radar the key technology for autonomous driving: From detection and ranging to environmental understanding" - https://ieeexplore.ieee.org/abstract/document/7485214 https://ieeexplore.ieee.org/abstract/document/7485214 Real-time SLAM has also been done with vision + inertial navigation for UAVs; A synchronized visual-inertial sensor system with FPGA pre-processing for accurate real-time SLAM - https://ieeexplore.ieee.org/abstract/document/6906892 https://ieeexplore.ieee.org/abstract/document/6906892 - https://www.research-collection.ethz.ch/bitstream/handle/20.500.11850/81914/eth-8003-01.pdf https://www.research-collection.ethz.ch/bitstream/handle/20.... Some people have proposed laser range finders with ultrasound (sonar); 'This article addresses the problem of performing SLAM under reduced visibility conditions by proposing a sensor fusion layer which takes advantage from complementary characteristics between a laser range finder (LRF) and an array of sonars. This sensor fusion layer is ultimately used with a state-of-the-art SLAM technique to be resilient in scenarios where visibility cannot be assumed at all times.' A Sensor Fusion Layer to Cope with Reduced Visibility in SLAM - https://link.springer.com/article/10.1007/s10846-015-0180-8 https://link.springer.com/article/10.1007/s10846-015-0180-8 - http://eprints.lincoln.ac.uk/16820/7/__ddat02_staffhome_jpartridge_A%20sensor%20fusion%20layer.%20Santos.pdf http://eprints.lincoln.ac.uk/16820/7/__ddat02_staffhome_jpar... There are enough datapoints between vision, ultrasound and radar for old school algorithms to do real time SLAM and make cost maps. So the problem and solution definitely isn't MOAR SENSARS.