Velodyne VLS-128 - Discreet Point Timing Calculation; Figure 9-4 Wireshark Position Packet Trace

To Next Page

To Previous Page

Figure 9-4 Wireshark Position Packet Trace

Legend:

light blue: Ethernet+IP+UDP packet header (42 bytes)

orange: Timestamp (4 bytes)

red: PPS status (1 byte)

green: NMEA GPRMC sentence (length varies)

9.4 Discreet Point Timing Calculation

For the purpose of geo-referencing LiDAR data, it is helpful to calculate the exact moment of a particular laser firing in

order to more closely associate it with time stamped data from an INS. By using the firing timing information given in

Figure

9-5 on the facing page

you are able to compute the exact firing time for each data point.

60 VLS-128 User Manual

DRAFT

Main Page

Default Chapter1
- Figure C-1 Interface Box Mechanical Drawing 50-1483 Rev1
- Table of Contents4
Chapter 1 • about this Manual16
- Manual Scope16
- Prerequisite Knowledge16
- Audience16
- Document Conventions16
- Table 1-1 Document Conventions16
Chapter 2 • VLS-128 Overview18
- Overview18
- Figure 2-1 Example 3D Sensing System18
- Product Models19
- Time of Flight19
- Data Interpretation Requirements19
- Table 2-1 3D Sensing System Components19
Chapter 3 • Safety Precautions20
- Warning and Caution Definitions20
  - Caution Hazard Alerts20
- Safety Overview20
Chapter 4 • Unboxing & Verification22
- What's in the Box22
- Verification Procedure23
Chapter 5 • Installation & Integration28
- Overview28
- Mounting28
- Encapsulation, Solar Hats, and Ventilation29
- Connections29
Chapter 6 • Key Features31
- Calibrated Reflectivity31
- Laser Return Modes31
- Phase Locking Multiple Sensors36
- Figure 6-5 Forestry Application Multiple Returns36
- Figure 6-6 Phase Locking Example37
Chapter 7 • Sensor Inputs38
- Power Requirements38
- Interface Box Signals39
- Table 7-1 Interface Box Signals39
- Figure 7-1 Interface Box (Sensor Power and Data Connections)39
- Ethernet Interface40
- GPS, Pulse Per Second (PPS) and NMEA GPRMC Message40
Chapter 8 • Sensor Operation49
- Firing Sequence49
- Throughput Calculations49
- Rotation Speed (RPM)50
Chapter 9 • Sensor Data52
- Sensor Origin and Frame of Reference52
- Calculating X,Y,Z Coordinates from Collected Spherical Data52
- Packet Types and Definitions53
- Discreet Point Timing Calculation60
- Figure 9-4 Wireshark Position Packet Trace60
- Figure 9-5 Firing Sequence Timing61
- Precision Azimuth Calculation62
- Figure 9-6 Single Return Mode Timing Offsets (in Μs)62
- Figure 9-7 Dual Return Mode Timing Offsets (in Μs)62
- Figure 9-8 VLS-128 Azimuth Offsets by Elevation63
- Figure 9-9 VLS-128 Laser Pattern64
- Converting PCAP Files to Point Cloud Formats65
Chapter 10 • Sensor Communication67
- Web Interface67
- Sensor Control with Curl75
Chapter 11 • Troubleshooting86
- Troubleshooting Process86
  - Table 11-1 Common Problems and Resolutions86
  - Turned DHCP On, Lost Contact with Sensor88
- Service and Maintenance88
  - Fuse Replacement88
- Technical Support89
- Return Merchandise Authorization (RMA)89
Appendix A • Sensor Specifications90
Appendix B • Firmware Update91
- Firmware Update Procedure91
Appendix C • Mechanical Diagrams99
- Interface Box Mechanical Drawing99
- Mechanical Drawing99
- Optical Keep out Zone99
- Figure C-2 VLS-128 Mechanical Drawing 86-0137 REV a101
- Figure C-3 VLS-128 Optical Keep out Zone 86-0137 REV a102
Appendix D • Wiring Diagrams103
- Interface Box Wiring Diagram104
- Figure D-1 Interface Box Wiring Diagram 86-0107A104
- Interface Box Schematic105
- Figure D-2 Interface Box Schematic 69-8230A105
Appendix E • Veloview106
- Features106
- Install Veloview107
- Visualize Streaming Sensor Data107
- Figure E-1 Veloview Open Sensor Stream107
- Capture Streaming Sensor Data to PCAP File108
- Replay Captured Sensor Data from PCAP File108
- Figure E-2 Veloview Record Button108
- Figure E-3 Veloview Open Capture File109
- Figure E-4 Veloview Play Button109
- Figure E-5 Veloview Spreadsheet Tool110
- Figure E-6 Veloview Data Point Table110
- Figure E-7 Veloview Show Only Selected Elements111
- Figure E-8 Veloview Select All Points111
- Figure E-9 Veloview List Selected Points112
Appendix F • Laser Pulse113
- The Semiconductor Laser Diode113
- Figure F-1 Laser Diode Concept113
- Laser Patterns114
- Table F-1 VLS-128 Beam Divergence115
Appendix G • Time Synchronization116
- Introduction116
- Background116
- Figure G-1 Web Interface PPS and GPS Qualifier Option Selections116
- PPS Qualifier117
- GPS Qualifier118
- Application118
- Logic Tables118
- Figure G-3 Sub-Second Counter Behavior118
- Figure G-4 Minutes and Seconds Counter Behavior119
Appendix H • Phase Lock120
- Phase Lock120
- Field of View123
- Status123
- Figure H-5 Sensor Data Shadows123
Appendix I • Sensor Care125
- Cleaning the Sensor125
Appendix J • Network Configuration128
- Ethernet and Network Setup128
  - Defaults128
  - Establishing Communication Via Ethernet128
- Network Considerations129

Velodyne VLS-128 - Discreet Point Timing Calculation; Figure 9-4 Wireshark Position Packet Trace

Table of Contents

Related product manuals