Change Run-Time Parameters

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3.Parse the packets for rotation, block, distance and intensity data. Each sensor’s LIFO data packet has a 1206 byte payload consisting of 12 blocks of 100 byte firing data followed by 6 bytes of calibration and other information pertaining to the sensor.

Each 100 byte record contains a block identifier, then a rotational value followed by 32 3-byte combinations that report on each laser fired for the block. Two bytes report distance to the nearest 0.2 cm, and the remaining byte reports intensity on a scale of 0 -255. 12 100 byte records exist, therefore, 6 records exist for each block in each packet. For more on packet construction, see Appendix E.

4.Apply the calibration factors to the data. Each of the sensor’s lasers is fixed with respect to vertical angle and offset to the rotational index data provided in each packet. For each data point issued by the sensor, rotational and horizontal correction factors must be applied to determine the point’s location in 3D space referred to by the return. Intensity and distance offsets must also be applied. Each sensor comes from Velodyne’s factory calibrated using a dual-point calibration methodology, explained further in Appendix F.

The minimum return distance for the sensor is approximately 3 feet (0.9 meters). Ignore returns closer than this.

A file on the CD called “HDL Source Example” shows the calculations using the above correction factors. This DSR uses this code to determine 3D locations of sensor data points.

5.Plot or store the data as needed. For DSR, the point-cloud data, once determined, is plotted onscreen. The source to do this can be found on the CD and is entitled “HDL Plotting Example.” DSR uses OpenGL to do its plotting.

You may also want to store the data. If so, it may be useful to timestamp the data so it can be referenced and coordinated with other sensor data later. The sensor has the capability to synchronize its data with GPS precision time. For more in this capability, see page 11.

The sensor has several run-time parameters that can be changed using the RS-232 serial port. For all commands, use the following serial parameters:

•Baud 9600

•Parity: None

•Data bits: 8

•Stop bits: 1

All serial commands, except one version of the spin rate command, store data in the sensor’s flash memory. Data stored in flash memory through serial commands is retained during firmware updates or power cycles.

The sensor has no echo back feature, so no serial data is returned from the sensor. Commands can be sent using a terminal program or by using batch files (e.g. .bat). A sample .bat file is shown below.

Sample Batch File (.bat)

MODE COM3: 9600,N,8,1 COPY SERCMD.txt COM3 Pause

Sample SERCMD.txt file

This command sets the spin rate to 300 RPM and stores the new value in the unit’s flash memory.

#HDLRPM0300$

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HDL-64E S2, HDL-64E S2.1 specifications

The Velodyne Acoustics HDL-64E S2.1 and HDL-64E S2 represent cutting-edge advancements in Lidar technology, specifically designed for autonomous vehicle navigation and mapping applications. These high-definition lidar sensors are acclaimed for their precision, reliability, and robustness, making them indispensable tools in various industries, from robotics to transportation.

One of the defining features of the HDL-64E series is its 64 laser channels, which allow for high-resolution 3D mapping of the environment. This multi-channel design significantly improves the sensor's ability to capture fine details in the surrounding area, providing a complete spatial representation necessary for autonomous driving. The HDL-64E S2.1 and S2 can generate dense point clouds with over 1.3 million points per second, facilitating real-time data acquisition and processing capabilities.

The HDL-64E series employs advanced technologies for optimal performance. Its 360-degree horizontal field of view and a vertical field of view ranging from -15 to +15 degrees allow the sensors to detect and classify objects in a comprehensive manner. This feature is crucial for ensuring the safety and efficacy of autonomous vehicles, as it enables them to perceive their surroundings from multiple angles.

In terms of accuracy, the HDL-64E models boast a measurement range of up to 120 meters, with an accuracy of ±2 centimeters. This level of precision ensures that autonomous systems can make informed decisions based on reliable data, essential for avoiding obstacles and navigating complex environments.

The sensors are designed to operate effectively in a range of environmental conditions. With IP67-rated waterproofing and robustness against dust and debris, the HDL-64E S2.1 and S2 are built to withstand challenging operating environments, thus ensuring continuous, dependable performance.

Integration of the HDL-64E series into existing systems is streamlined, thanks to its advanced Ethernet interface. This functionality makes it easier for developers to incorporate the Lidar data into existing software frameworks, enhancing the usability of the sensor in various applications.

In summary, the Velodyne Acoustics HDL-64E S2.1 and HDL-64E S2 represent a significant leap forward in Lidar technology, featuring high-resolution mapping, advanced detection capabilities, and rugged design. These characteristics make them an ideal choice for companies looking to implement reliable and precise sensing solutions in their autonomous systems.

Velodyne Acoustics HDL-64E S2.1 user manual Change Run-Time Parameters, Sample Batch File .bat

Models: HDL-64E S2 HDL-64E S2.1

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