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Appendix F • 

Laser Pulse

This section provides details on your sensor’s laser diodes, the laser pulse and scan patterns, and certain beam char-
acteristics of the laser pulses.

F.1 The Semiconductor Laser Diode

113

F.2 Laser Patterns

114

F.2.1 Laser Spot Pattern

114

F.2.2 Laser Scan Pattern

114

F.2.3 Beam Divergence

115

F.1 The Semiconductor Laser Diode

The source of each laser pulse in the sensor is a semiconductor laser diode. The laser diode is a series of stacked p-n junc-
tions similar, at least in concept, to that shown in 

Figure F-1  below

. When a current is applied across the junction, photons 

are produced and routed out one end to form a tightly focused laser beam.

Note:   The physics of laser diodes can be found elsewhere on the Internet. Start by searching for 

p-n junction, laser 

diode, and principles of semiconductor laser diodes.

Figure F-1 Laser Diode Concept

Appendix F • Laser Pulse

113

DRAFT

Содержание VLS-128

Страница 1: ...VLS 128 User Manual 63 9483 Rev A DRAFT ...

Страница 2: ...egistered users Limited Warranty Except as specified below products sold hereunder shallbe free from defects in materials and workmanship and shallcon form to Velodyne s published specifications or other specifications accepted in writing by Velodyne for a period of one 1 year from the date of shipment of the products The foregoing warranty does not apply to any Garmin products other products not ...

Страница 3: ...e Release Notes VLS 128 5 0 6 0 2018 xx xx DRAFT release of B1 version Added thermaland ADC fields to the Position Packet For fulldetails see the Release Notes at http www velodynelidar com downloads html firmware Last Updated 2018 09 12 3 DRAFT ...

Страница 4: ... Caution Hazard Alerts 20 3 2 Safety Overview 20 3 2 1 Electrical Safety 20 3 2 2 Mechanical Safety 20 3 2 3 Laser Safety 20 Chapter 4 Unboxing Verification 4 1 What s in the Box 22 4 1 1 Bulkhead Connectors 22 4 1 1 1 Ethernet Bulkhead Connector 22 4 1 1 2 Power GPS Bulkhead Connector 22 4 1 2 Accessories 22 4 1 3 Variants 23 4 2 Verification Procedure 23 4 2 1 Network Setup in Isolation 23 4 2 2...

Страница 5: ...urn Mode 32 6 3 Phase Locking Multiple Sensors 36 Chapter 7 Sensor Inputs 7 1 Power Requirements 38 7 2 Interface Box Signals 39 7 3 Ethernet Interface 40 7 4 GPS Pulse Per Second PPS and NMEA GPRMC Message 40 7 4 1 GPS Input Signals 40 7 4 2 Electrical Requirements 40 7 4 3 Timing and Polarity Requirements 40 7 4 4 GPS Connection Scenarios 43 7 4 4 1 Connecting a Garmin 18x LVC GPS Receiver 43 7 ...

Страница 6: ...peed Fluctuation and Point Density 51 Chapter 9 Sensor Data 9 1 Sensor Origin and Frame of Reference 52 9 2 Calculating X Y Z Coordinates from Collected Spherical Data 52 9 3 Packet Types and Definitions 53 9 3 1 Definitions 53 9 3 1 1 Firing Sequence 54 9 3 1 2 Laser Channel 54 9 3 1 3 Data Point 54 9 3 1 4 Azimuth 54 9 3 1 5 Data Block 54 9 3 1 6 Time Stamp 54 9 3 1 7 Factory Bytes 55 9 3 2 Data...

Страница 7: ... 3 Command Line curl Examples 76 10 2 3 1 Get Diagnostic Data 76 10 2 3 2 Conversion Formulas 77 10 2 3 3 Interpret Diagnostic Data 77 10 2 3 3 1 top hv 77 10 2 3 3 2 top lm20_temp 78 10 2 3 3 3 top pwr_5v 78 10 2 3 3 4 top pwr_2_5v 78 10 2 3 3 5 top pwr_3_3v 78 10 2 3 3 6 top pwr_raw 79 10 2 3 3 7 top pwr_vccint 79 10 2 3 3 8 bot i_out 79 10 2 3 3 9 bot lm20_temp 79 10 2 3 3 10 bot pwr_1_2v 80 10...

Страница 8: ... 3 17 Set Gateway 83 10 2 3 18 Set DHCP 83 10 2 4 curl Example using Python 84 Chapter 11 Troubleshooting 11 1 Troubleshooting Process 86 11 1 1 Turned DHCP On Lost Contact With Sensor 88 11 2 Service and Maintenance 88 11 2 1 Fuse Replacement 88 11 3 Technical Support 89 11 3 1 Purchased through a Distributor 89 11 3 2 Factory Support 89 11 3 3 Support Desk 89 11 4 Return Merchandise Authorizatio...

Страница 9: ...107 E 4 Capture Streaming Sensor Data to PCAP File 108 E 5 Replay Captured Sensor Data from PCAP File 108 Appendix F Laser Pulse F 1 The Semiconductor Laser Diode 113 F 2 Laser Patterns 114 F 2 1 Laser Spot Pattern 114 F 2 2 Laser Scan Pattern 114 F 2 3 Beam Divergence 115 Appendix G Time Synchronization G 1 Introduction 116 G 2 Background 116 G 3 PPS Qualifier 117 G 3 1 Require GPS Receiver Valid...

Страница 10: ...hree 126 I 1 6 Method Four 127 Appendix J Network Configuration J 1 Ethernet and Network Setup 128 J 1 1 Defaults 128 J 1 2 Establishing Communication via Ethernet 128 J 2 Network Considerations 129 J 2 1 Throughput Requirements 129 J 2 2 Single Sensor Transmitting to a Broadcast Address 130 J 2 3 Multiple Sensors in the Same Network 130 J 2 3 1 Multiple Sensors Transmitting to a Broadcast Address...

Страница 11: ... Resolution 51 Table 9 1 Factory Byte Values 55 Table 9 2 Position Packet Structure Field Offsets 58 Table 9 3 PPS Status Byte Values 59 Table 10 1 Configuration Screen Functionality and Features 68 Table 10 2 System Screen Functionality and Features 71 Table 10 3 Info Screen Functionality and Features 72 Table 10 4 System Screen Functionality and Features 74 Table 11 1 Common Problems and Resolut...

Страница 12: ...1 Figure 7 4 PPS Signal Followed 600 ms later by NMEA GPRMC Message 41 Figure 7 5 RS 232 Example Transmission 42 Figure 7 6 Garmin 18x LVC Configuration 43 Figure 7 7 Garmin GPRMC Message 44 Figure 7 8 DB9 Pin outs DTE and USB to Serial Adapter 45 Figure 7 9 Signal Directly from UART incorrect polarity 45 Figure 7 10 Inverted Signal from UART correct polarity 46 Figure 8 1 Point Density Example 51...

Страница 13: ...Button 108 Figure E 3 VeloView Open Capture File 109 Figure E 4 VeloView Play Button 109 Figure E 5 VeloView Spreadsheet Tool 110 Figure E 6 VeloView Data Point Table 110 Figure E 7 VeloView Show Only Selected Elements 111 Figure E 8 VeloView Select All Points 111 Figure E 9 VeloView List Selected Points 112 Figure F 1 Laser Diode Concept 113 Figure F 2 Laser Spot Shape 114 Figure G 1 Web Interfac...

Страница 14: ...Figure J 3 Multiple Sensors Improper Network Setup 131 Figure J 4 Multiple Sensors Proper Network Setup 131 14 VLS 128 User Manual DRAFT ...

Страница 15: ...esolution at 600 RPM 50 Equation 10 1 Standard Voltage Conversion 77 Equation 10 2 Standard Current Conversion 77 Equation 10 3 Standard Temperature Conversion 77 Equation F 1 Gap Between Scan Lines 114 Equation H 1 Arc of Shadow 123 15 DRAFT ...

Страница 16: ...oking to understand sensor output data 1 4 Document Conventions This document uses the following typographic conventions Convention Description Bold Indicates text on a window other than the window title including menus menu options buttons fields and labels Example Click OK Italic Indicates a variable which is a placeholder for actualtext provided by the user or system Example copy source file ta...

Страница 17: ...mportant information They callattention to an operating procedure or practice which may enhance user interaction with the product Notes may also be used to prevent information loss or product damage Chapter 1 About This Manual 17 DRAFT ...

Страница 18: ...he assembly of laser detector pairs spins rapidly within its fixed housing to scan the surrounding environment firing each laser over 18 500 times per second providing in real time a rich set of 3D point data Advanced digitalsignalprocessing and waveform analysis provide highly accurate long range sensing as wellas cal ibrated reflectivity data enabling easy detection of retro reflectors like stre...

Страница 19: ... 3 Time of Flight Velodyne LiDAR sensors use time of flight ToF methodology When each IR laser emits a laser pulse its time of shooting and direction are registered The laser pulse travels through air untilit hits an obstacle which reflects some of the energy A portion of that energy is received by the paired IR detector which registers the time of acquisition and power received 2 4 Data Interpret...

Страница 20: ...ces The icon shown in the left column displays the spe cific concern in this case a hot surface 3 2 Safety Overview 3 2 1 Electrical Safety IMPORTANT Read allinstallations instructions before powering up the sensor Note The VLS 128 sensor is not field serviceable For servicing and repair the equipment must be completely shut off removed packaged carefully and shipped back to the manufacturer s fac...

Страница 21: ...The product fulfills the requirements of IEC 60825 1 2014 Safety of Laser Products There are no controls or adjustments on the sensor itself that are user accessible Never look directly at the transmitting laser through a magnifying device Chapter 3 Safety Precautions 21 DRAFT ...

Страница 22: ...e shroud Velodyne USB memory stick containing User Manual VeloView application installers for PC Mac and linux Sensor sample data i e pcap files Miscellaneous documents 4 1 1 Bulkhead Connectors The VLS 128 has two bulkhead connectors on the bottom of the sensor enabling cabling to be hidden from public view while shielding them and the connectors from the elements Placement of the connectors can ...

Страница 23: ...on at a workbench or desk You llneed AC power You won t need a GPS receiver Note Due to the large volume of data produced by the sensor when scanning users are cautioned against connecting it to a corporate network 1 Unpack the sensor and its accessories and place them on a workbench or desk Ensure the sensor is upright with clear space around it 2 Create a simple network setup with a test compute...

Страница 24: ...ubnet mask 255 255 255 0 When using a Windows based computer you can press the TAB key and the subnet mask field willautomatically populate with the default mask for the network class indicated by the IP address entered which is 255 255 255 0 in this case Figure 4 1 Sensor Network Settings 7 Click OK Gateway and DNS are not necessary when testing in isolation In some cases it may be necessary to d...

Страница 25: ...tions 2 Connect power to the sensor s Interface Box When power is applied two green LEDs in the Interface Box light up The sensor begins scanning its environment and transmitting data approximately 30 seconds after power up 3 On the computer point a browser to http 192 168 1 201 4 The sensor s Web Interface should appear Figure 4 3 below The Web Interface provides access to many of the sensor s co...

Страница 26: ...ailored for Velodyne LiDAR sensors Other visualization software e g ROS DSR and PCL can perform similar functions and may be used instead VeloView is documented in more detailin VeloView on page 106 If the application isn t already on the computer perform the procedure detailed in InstallVeloView on page 107 Older versions should be updated to at least the version installed by following the proced...

Страница 27: ... 4 4 VeloView Open Sensor Stream 4 The Sensor Configuration dialog willappear Chapter 4 on page 22 Select the correct sensor type then click OK 5 VeloView begins displaying the sensor data stream See Unboxing Verification on page 22 Above is an example of a VeloView screen in an office workbench or lab scenario Chapter 4 Unboxing Verification 27 DRAFT ...

Страница 28: ...ystem see GPS Pulse Per Second PPS and NMEA GPRMC Message on page 40 The typicalsensor setup uses a standard computer or laptop connected to the sensor However it is recommended to use at least a 1 Gbps Ethernet adapter to accommodate the sensor data rate 5 2 Mounting The sensor base provides four M8 mounting holes and two precision locating holes for locator pins The sensor may be mounted at any ...

Страница 29: ...ng a replaceable fuse and a reverse current protection diode When con nected correctly to power the diode allows current through to the sensor If however the power and ground are switched the diode blocks current flow protecting the sensor Opening the Interface Box and making modifications inside such as replacing the fuse or reverse current protection diode or repairing wires is permitted For mor...

Страница 30: ...n the VLS 128 is stationary is approximately 30 W Under certain con ditions power consumption willincrease To assure proper operations during those conditions the recommended power supply output i e power in to the sensor is 60 W continuous 65 W peak 2 Voltage 12 V is recommended but the sensor can support 9 32V DC clean power As with allelectronic equip ment a large change in voltage levels in a ...

Страница 31: ...lues from 0 to 110 for reflectivities from 0 to 100 Retroreflectors report values from 111 to 255 where 255 represents an idealreflection Note When a laser pulse doesn t result in a measurement such as when a laser is shot skyward both distance and reflectivity values willbe 0 The key is a distance of 0 because 0 is a valid reflectivity value i e one step above noise 6 2 Laser Return Modes The VLS...

Страница 32: ...e last return or both returns depending on the laser return mode setting If the setting is Strongest and a pulse produces multiple returns only the strongest reflec tion results in a measurement Likewise if the setting is Last only the last time wise reflection results in a measurement This could be used to measure distances to the ground from the air 6 2 3 Dual Return Mode Figure 6 2 on the facin...

Страница 33: ...return the second strongest return is reported The majority of the beam hits the far walland is in this case the strongest return It s entirely possible however that the far wallmight be far enough away that despite reflecting the majority of the beam the return from the near wallwould be the strongest return Chapter 6 Key Features 33 DRAFT ...

Страница 34: ... with Second Strongest Return It s also possible that a smallportion of the beam clips a retro reflector and returns more energy than the majority of the beam as in Figure 6 4 on the facing page 34 VLS 128 User Manual DRAFT ...

Страница 35: ...e measurement of the height of trees is desired Figure 6 5 on the next page indicates a sample response when the laser pulse initially hits the upper canopy penetrates it and eventually hits the ground producing multiple returns Which laser return mode would be best in this situation Chapter 6 Key Features 35 DRAFT ...

Страница 36: ...s a phase locking feature that enables the user to controlwhere the laser firings overlap The Phase Lock feature can be used to synchronize the relative rotationalposition of multiple sensors based on the PPS signaland relative sensor orientation To operate correctly the PPS signalmust be present and locked Phase locking works by offsetting the firing position based on the rising edge of the PPS s...

Страница 37: ...n Figure 6 6 above indicate the firing direction of the sensor s laser at the moment it receives the rising edge of the PPS signal Additionalinformation for phase locking multiple sensors is located in Phase Lock on page 120 Chapter 6 Key Features 37 DRAFT ...

Страница 38: ...Signals 39 7 3 Ethernet Interface 40 7 4 GPS Pulse Per Second PPS and NMEA GPRMC Message 40 7 4 1 GPS Input Signals 40 7 4 2 Electrical Requirements 40 7 4 3 Timing and Polarity Requirements 40 7 4 4 GPS Connection Scenarios 43 7 4 5 NMEA Message Formats 46 7 4 6 Accepting NMEA Messages Via Ethernet 48 7 1 Power Requirements Power requirements are detailed in Chapter 5 Power on page 29 38 VLS 128 ...

Страница 39: ...nal Specifications Signal Input Output Black Ground Input Yellow GPS Sync Pulse Input White GPS SerialReceive Input Light Orange Ethernet TX Output Orange Ethernet TX Output Light Blue Ethernet RX Input Blue Ethernet RX Input Table 7 1 Interface Box Signals Chapter 7 Sensor Inputs 39 DRAFT ...

Страница 40: ...ats 7 4 1 GPS Input Signals The serialdata output from the GPS INS is connected to the sensor s Interface Box via the screw terminallabeled GPS RECEIVE The PPS output from the GPS INS is connected to the sensor s Interface Box via the screw terminallabeled GPS PULSE The ground signalfrom the GPS INS is connected to the sensor s Interface Box via the screw terminallabeled GROUND Note You can use th...

Страница 41: ...Figure 7 3 PPS SignalClosely Followed by NMEA GPRMC Message Figure 7 4 PPS SignalFollowed 600 ms later by NMEA GPRMC Message Chapter 7 Sensor Inputs 41 DRAFT ...

Страница 42: ...logical1 High voltages are spaces and represent a logical0 The serialline idle state MARK is a low voltage indicating a logical1 When the start bit is asserted the positive voltage will be asserted representing a logical0 As an example the transmission of an ASCII character is shown in Figure 7 5 below Figure 7 5 RS 232 Example Transmission 42 VLS 128 User Manual DRAFT ...

Страница 43: ... supplied Garmin 18x LVC GPS receiver connecting to it from a computer s serialport and connecting directly from a microcomputer s UART 7 4 4 1 Connecting a Garmin 18x LVC GPS Receiver As an option Velodyne LiDAR offers a Garmin 18x LVC GPS Receiver P N 80 GPS18LVC pre configured per Figure 7 6 below for optimized operation with your sensor GPRMC is configured by default but GPGGA is also supporte...

Страница 44: ...hronize your sensor s timestamp with pre cision GPS time The signals from the Garmin receiver willbe similar to those shown in Figure 7 7 below where the signalis normally low and zeros are represented by the high voltage Figure 7 7 Garmin GPRMC Message 44 VLS 128 User Manual DRAFT ...

Страница 45: ...e Box and make the following con nections to the terminalscrew strip in the Interface Box DB9 pin 3 to GPS RECEIVE DB9 pin 5 connects to GROUND 7 4 4 3 Connecting to a microcomputer s UART In other situations you may wish to source NMEA messages from a microcomputer such as a Raspberry Pior Arduino instead The native signalcoming from the microcomputer s UART willhave incorrect polarity In this in...

Страница 46: ...at in version 2 3 a Fix Mode Indicator field was added after Magnetic Variation and before the Checksum NMEA messages are terminated with sentence delimiter CR LF HEX 0D0A 7 4 5 1 Pre NMEA Version 2 3 Message Format Table 7 2 on the facing page provides a description of the pre NMEA 2 3 message format contents shown below GPRMC 123519 A 4807 038 N 01131 000 E 022 4 084 4 230394 003 1 W 6A 46 VLS 1...

Страница 47: ...description of the post NMEA 2 3 message format contents shown below GPRMC 123519 A 4807 038 N 01131 000 E 022 4 084 4 230394 003 1 W A 07 Value Description GPRMC Recommended Minimum sentence 123519 Fix taken at 12 35 19 UTC A Receiver status A Active V Void 4807 038 N Latitude 48 deg 07 038 N 01131 000 E Longitude 11 deg 31 000 E 022 4 Speed over the ground knots 084 4 Track made good degrees Tru...

Страница 48: ...smits NMEA sentences on the socket 2 A host transmits NMEA sentences in UDP packets to the sensor s UDP port 10110 3 A host transmits NMEA sentences in UDP packets to a broadcast address on port 10110 with an NMEA sen tence 1 and 2 require knowledge of the sensor s IP address 3 does not but it may load devices on the network that don t want the packets Note The supported NMEA sentence and syntax a...

Страница 49: ...h firing groups After the 16th firing group there is a second longer maintenance period of 7 995 μs Therefore the timing cycle to fire and recharge all128 lasers is given by 8 2 665 μs 2 665 μs 8 2 665 μs 7 995 μs 53 3 μs This pattern is illustrated in Figure 9 5 on page 61 8 2 Throughput Calculations Some terms used here are defined in Packet Types and Definitions on page 53 8 2 1 Data Packet Rat...

Страница 50: ...more on setting rotation speed Note In VeloView one rotation can be referred to as a single frame of data beginning and ending at approximately 0 azimuth The number of frames per second of data generated depends entirely on the RPM setting e g 600 RPM 60 s min 10 frames per second Choice of RPM is up to the user and depends on the application For example an autonomous vehicle may wish to increase ...

Страница 51: ...n the azimuthalgaps with every revolution Consequently over time the sensor automatically fills in the gaps between successive laser firings A data set from a stationary sensor provides an example of the how the sensor fills in the gaps and the effect is demon strated in Figure 8 1 below On the left is a single frame of data On the right is the same frame and the nine preceding frames overlaid on ...

Страница 52: ...of Reference The sensor reports distances relative to itself in sphericalcoordinates radius r elevation ω azimuth α Sensor data origin 0 0 0 is 66 11 mm 2 603 inches above the sensor base on the center axis as shown in Figure 1 see the side and top views which also shows the sensor s frame of reference See also VLS 128 MechanicalDrawing on page 101 9 2 Calculating X Y Z Coordinates from Collected ...

Страница 53: ...mode provides the information your software needs to automatically adjust to different data formats Position packets provide a copy of the last NMEA message received either GPRMC or GPGGA if you ve configured your sensor to synchronize with a GPS time source See GPS Pulse Per Second PPS and NMEA GPRMC Message on page 40 for additionalinformation Position packets also provide a byte identifying the...

Страница 54: ...0 616 m Calibrated reflectivity is reported on a scale of 0 to 255 as described in Calibrated Reflectivity on page 31 The elevation angle ω is inferred based on the position of the data point within a data block A distance of 0 indicates a non measurement The laser is either off or a measurable reflection was not returned in time 9 3 1 4 Azimuth A two byte azimuth value α appears after the flag by...

Страница 55: ...ription of electricaland timing requirements can be found in GPS Pulse Per Second PPS and NMEA GPRMC Message on page 40 A fulldescription of timing options can be found in Time Synchronization on page 116 9 3 1 7 Factory Bytes Every data packet includes a pair of bytes called the Factory Bytes Their values indicate how azimuths and data points are organized in the packet Their packet locations val...

Страница 56: ...yte timestamp and two factory bytes There are two formats for the data packet Single Return Mode either Strongest or Last DualReturn Mode See Laser Return Modes on page 31 for an illustration of what Strongest Last and Dualmean in this context There are severalkey differences between the packet structures Figure 9 2 VLS 128 Single Return Mode Data Structure 56 VLS 128 User Manual DRAFT ...

Страница 57: ... e all zeros The position packet is a 554 byte UDP packet received on port 8308 by default Protocolheaders account for the first 42 bytes Payload length is 512 bytes The structure of the position packet minus the 42 byte protocolheader is given in Table 9 2 on the next page Note You may notice the timestamps in the position packets are occasionally out of order with respect to the data pack ets Th...

Страница 58: ...ration 1 0xC5 These bit fields are not mutually exclusive The con dition is True if the bit field value is 1 b0 Calibration in progress b1 Delta temperature limit has been met b2 Periodic time elapsed limit has been met Each status bit reflects the current sensor condition but does not imply any calibration occurred µsec since top of the hour TOH 4 0xC6 0xC9 Number of microseconds elapsed since th...

Страница 59: ...padded to end of payload with nullbytes Value Description 0 No PPS detected 1 Synchronizing to PPS 2 PPS Locked 3 Error Table 9 3 PPS Status Byte Values A position packet is shown in the figure below Packet offsets are on the left raw data bytes in hex are in the center and the ASCII interpretation is on the right Chapter 9 Sensor Data 59 DRAFT ...

Страница 60: ...screet Point Timing Calculation For the purpose of geo referencing LiDAR data it is helpfulto 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 ...

Страница 61: ... above and Figure 9 8 on page 63 To calculate the exact time in microseconds of each data point in a packet first number the points in the firing sequence from 0 to 127 This becomes the data point index aka Laser ID for your calculations Next number the firing sequences 0 to 2 This becomes your sequence index The timestamp in the packet indicates the time of the 4th firing group in the packet You ...

Страница 62: ...ttern at the moment the first firing group in a fir ing sequence occurred But because allof the lasers are offset from the center line by fixed amounts an azimuthaloffset must be applied to determine the precise azimuth of each data point The figures below provide both the angular offsets to apply per laser and an illustration of where the offsets put the laser in the firing pattern 62 VLS 128 Use...

Страница 63: ...Figure 9 8 VLS 128 Azimuth Offsets by Elevation Chapter 9 Sensor Data 63 DRAFT ...

Страница 64: ... 9 7 on page 62 Consider a single data packet with 12 data blocks In single return mode this fits 3 firing sequences each sequence taking four consecutive data blocks The azimuth at the top of each data block represents the azimuth reported at the moment the first firing group of 8 lasers in the sequence was fired Assuming the rotationalspeed is constant over the 53 3 µs firing sequence you can us...

Страница 65: ...ap 2 665 μs K 53 3 μs Precision_Azimuth K 1 Precision_Azimuth K Apply the azimuth offsets Precision_Azimuth K Precision_Azimuth K azimuth_offset K Precision_Azimuth K 1 Precision_Azimuth K 1 azimuth_offset K 1 Adjust for any rollover If Precision_Azimuth K 360 Then Precision_Azimuth K Precision_Azimuth K 360 Endif If Precision_Azimuth K 1 360 Then Precision_Azimuth K 1 Precision_Azimuth K 1 360 En...

Страница 66: ...g the location and orientation of the sensor at every moment is recorded with an InertialNavigation System INS An INS combines a GlobalPositioning System GPS receiver with an InertialMeasurement Unit IMU Data from the both the INS and LiDAR sensor are time synchronized to the GPS satellite s reference clock enabling the user to match each LiDAR data point with its corresponding position and orient...

Страница 67: ...74 10 2 Sensor Control with curl 75 10 2 1 Using curl with Velodyne LiDAR Sensors 75 10 2 2 curl Command Parameters 75 10 2 3 Command Line curl Examples 76 10 2 4 curl Example using Python 84 10 1 Web Interface The easiest way to controla sensor s operation is through its Web Interface It has four screens This section provides an explanation of the feature sets and functionality on each screen Cha...

Страница 68: ...s laser ON or OFF ON Return Type Strongest Sensor provides only the strongest detected return Last Sensor provides only the last temporally detected return Dual Sensor provides both the strongest and last returns If the last is also Strongest Table 10 1 Configuration Screen Functionality and Features 68 VLS 128 User Manual DRAFT ...

Страница 69: ...d ON OFF Set Activates the changes OFF Phase Lock Used to synchronize the firing of two or more sensors The offset is used to set the azimuth at which the laser fires in conjunction with the PPS signal s rising edge Requires a valid PPS signal Offset Enter the offset as the desired degrees multiplied by 100 For example if the desired offset is 270º enter 27000 Set Activates the changes OFF 0 Host ...

Страница 70: ...redths of a degree Laser State Indicates the current laser array firing status ON DISABLED See Time Synchronization on page 116 for additionalinformation on the PPS and GPS Qualifier functions 10 1 1 1 MAC Address It may be advantageous to change the sensor s MAC address for asset management in multi sensor situations where the MAC address is the closest thing to a hard sensor ID or as an anti tra...

Страница 71: ...8 System Screen Function Description Update Firmware Choose File Enables user to select a new firmware image file Update Initiates the firmware update process Reset System Used to reset the system after a firmware update GPS Position See description in Table 10 1 on page 68 PPS See description in Table 10 1 on page 68 Motor State See description in Table 10 1 on page 68 Table 10 2 System Screen Fu...

Страница 72: ...te of the Application Watchdog Velodyne use only Type Velodyne Use Only HW Version Velodyne Use Only SOPC SYSID Velodyne Use Only SW Version Current operating firmware version Build Velodyne Use Only FPGA bottom board Board Top or Bottom board information Mode Velodyne use only Type Velodyne Use Only HW Version Velodyne Use Only Table 10 3 Info Screen Functionality and Features 72 VLS 128 User Man...

Страница 73: ...umber of the stored Failsafe and Application images SOPC SYSID Failsafe boot 00 Velodyne Use Only Application hdlbot 03 Velodyne Use Only GPS Position See description in Table 10 1 on page 68 PPS See description in Table 10 1 on page 68 Motor State See description in Table 10 1 on page 68 Laser State See description in Table 10 1 on page 68 Chapter 10 Sensor Communication 73 DRAFT ...

Страница 74: ... 2 5v Internalvoltage status 3 3v Internalvoltage status RAW Internalvoltage status VCCINT Internalvoltage status VHV Velodyne Use Only Bottom Board Scaled I out The sensor s electricalcurrent consumption 1 2v N A Temp Circuit board temperature 5v Internalvoltage status 2 5v Internalvoltage status 3 3v Internalvoltage status Table 10 4 System Screen Functionality and Features 74 VLS 128 User Manua...

Страница 75: ...and rework ing the command the Invoke WebRequest way Select one that works best for you The sections below show how to command and controla sensor from the command line using curl and from a Python pro gram using pycurl a Python binding for libcurl 10 2 1 Using curl with Velodyne LiDAR Sensors Note It is recommended to issue at most one curlcommand per second to the sensor curltakes care of the fo...

Страница 76: ...gateway 192 168 1 2 4 dhcp on off SpecialCommands to Save settings to NVRAM and Reset the sensor 1 http 192 168 1 201 cgi save a submit 2 http 192 168 1 201 cgi reset a reset_system 10 2 3 Command Line curl Examples 10 2 3 1 Get Diagnostic Data Returns a JSON formatted string containing values as seen on the Diagnostics page of the sensor s Web Interface Command curlhttp 192 168 1 201 cgi diag jso...

Страница 77: ...usable values Some fields are scaled by additional factors Note Operating range values in this section are subject to change 10 2 3 3 1 top hv The HV field comes from the sensor s top board It represents the high voltage bias to the APD Avalanche photodiode Its operating range is 150 0 V to 132 0 V To convert the raw value use Equation 10 1 above then scale the result by subtracting 5 0 and multip...

Страница 78: ...perating range is 4 8 V to 5 2 V To convert the raw value use Equation 10 1 on the previous page then scale the result by multiplying it by 2 0 Example pwr_5v 2075 raw value 2075 5 0 4096 2 533 2 533 2 0 5 066 V 10 2 3 3 4 top pwr_2_5v This is the top board s 2 5 V rail Its operating range is 2 3 V to 2 7 V To convert the raw value use Equation 10 1 on the previous page Example pwr_2_5v 2047 raw v...

Страница 79: ..._vccint 977 raw value 977 5 0 4096 1 193 V 10 2 3 3 8 bot i_out This is the sensor s input power line Its operating range is 0 3 A to 1 0 A It spikes whenever the motor spins up To convert the raw value use Equation 10 2 on page 77 Example i_out 2086 raw value 2086 5 0 4096 2 546 10 0 2 546 2 5 0 464 A 10 2 3 3 9 bot lm20_temp This field indicates the temperature of the bottom board Its operating ...

Страница 80: ...2_5v This is the bottom board s 2 5 V rail Its operating range is 2 3 V to 2 7 V To convert the raw value use Equation 10 1 on page 77 Example pwr_2_5v 2046 raw value 2046 5 0 4096 2 498 V 10 2 3 3 13 bot pwr_3_3v This is the bottom board s 3 3 V rail Its operating range is 3 1 V to 3 5 V To convert the raw value use Equation 10 1 on page 77 Example pwr_3_3v 2692 raw value 2692 5 0 4096 3 286 V 10...

Страница 81: ... button under the Configuration tab Command curlhttp 192 168 1 201 cgi snapshot hdl snapshot hdl 10 2 3 5 Get Sensor Status Returns sensor state data such as GPS PPS is present GPS position motor status phase and laser states Command curlhttp 192 168 1 201 cgi status json Example Response gps pps_state Absent position motor state On rpm 600 lock Off phase 0 laser state On 10 2 3 6 Set Motor RPM Se...

Страница 82: ...Strongest Last Dual This command sets the return type or mode of the sensor Choose one Strongest Last and Dual This has the same effect as selecting the Web Interface Return Type Command curl data returns Strongest Last Dual http 192 168 1 201 cgi setting Examples curl data returns Strongest http 192 168 1 201 cgi setting curl data returns Last http 192 168 1 201 cgi setting curl data returns Dual...

Страница 83: ...nterface s Telemetry Port field Command curl data tport 8309 http 192 168 1 201 cgi setting host 10 2 3 15 Set Network Sensor IP Address This sets the IP address of the device The default is 192 168 1 201 This has the same effect as entering an IP address in the Web Interface Network IP field Command curl data addr 192 168 1 200 http 192 168 1 201 cgi setting net 10 2 3 16 Set Netmask This sets th...

Страница 84: ...TTP response code is checked for success The first operation is to reset the sensor After a delay the script changes a couple of sensor parameters Waiting another 10 seconds for the motor to spin up sensor status is obtained and printed to standard out import pycurl try from io import BytesIO except ImportError from StringIO import StringIO as BytesIO try from urllib parse import urlencode except ...

Страница 85: ... rpm is s status laser state status motor rpm sensor close Typicaloutput looks like the following http 192 168 1 201 cgi reset data reset_system 204 OK http 192 168 1 201 cgi setting rpm 300 204 OK http 192 168 1 201 cgi setting laser on 204 OK Sensor laser is On motor rpm is 301 Chapter 10 Sensor Communication 85 DRAFT ...

Страница 86: ...e 88 if it s blown Rotor doesn t spin Verify Power connection and polarity Fuse in the Interface Box is okay See Fuse Replacement on page 88 if it s blown Unit spins but no data Verify Ethernet wiring is functional Packet output using another application e g VeloView Wireshark Receiving computer s network settings Correct static IP address in your computer s network settings No security software i...

Страница 87: ...packets from another service being seen by the sensor This can slow the sensor down Is the computer fast enough to keep up with the packet flow coming from the sensor Remove allnetwork devices and test with a computer directly connected to the sensor No Data Packets Only Telemetry Pack ets This is nearly always a power issue Check the following Update this Update this Update this GPS Not Syn chron...

Страница 88: ...apable of performing IP scans and ARP sweeps for various operating sys tems exist Any of them should be able to discover the sensor s IP address However this may be the least efficient most time consuming approach as 169 254 x x is a large list to scan 3 Once you have the address of the sensor change the IP address of the corresponding Ethernet interface on your computer to something on the same l...

Страница 89: ...MPORTANT In the Description field please describe the problem concisely including any non default sensor configuration and setup details as necessary 6 Attachments are limited to a maximum individualfile size of 20 MB No limit is placed on the number of attach ments nor on the totalsize of allattachments For very large files please host them somewhere suitable and include a link in the Description...

Страница 90: ...atory specifications have been moved to product data sheets found on the Velodyne LiDAR web site at this address http www velodynelidar com downloads html datasheets For additionalinformation contact Velodyne LiDAR Sales http www velodynelidar com contacts php 90 VLS 128 User Manual DRAFT ...

Страница 91: ...s the update in two stages This procedure works best with the Chrome browser 1 Point your browser to the Velodyne Downloads page at http velodyneLiDAR com downloads html Figure B 1 Velodyne Downloads Page 2 Click the FIRMWARE icon on the left to advance to the Firmware section Note the latest version available 3 Open the sensor s Web Interface in your browser and click the Info button 4 Check the ...

Страница 92: ...Figure B 2 Compare Firmware Versions Note The firmware image labeled Failsafe is the originalimage programmed into the sensor when it was man ufactured It cannot be updated 92 VLS 128 User Manual DRAFT ...

Страница 93: ...te Firmware 8 Using the dialog locate the new firmware file on your computer and select it 9 Verify that the correct file for your sensor modelhas been selected It must have the flash file extension 10 Click Update Firmware s Update button to initiate the update process Appendix B Firmware Update 93 DRAFT ...

Страница 94: ...ar indicating the percentage of update completion is displayed 12 When this first stage of the update is complete the Firmware Update Complete screen below is displayed But wait there s more Internally you ve updated the bottom board but not the top yet 94 VLS 128 User Manual DRAFT ...

Страница 95: ... The firmware image that you just uploaded is being prepared for use by the sensor 14 A second progress bar is shown Note This step should take approximately 70 seconds If it completes in less than 10 seconds an error occurred Instead of continuing perform the If An Error Occurs on page 98 procedure Appendix B Firmware Update 95 DRAFT ...

Страница 96: ...en processing completes press the Reset System button to finalize the update The sensor willperform a warm boot 16 The Configuration screen willbe shown when the sensor finishes rebooting 17 Return to the Info page 96 VLS 128 User Manual DRAFT ...

Страница 97: ...are dis abled Perform the If An Error Occurs on the next page procedure below to resolve the issue B 1 1 Special Procedure to Update Firmware The firmware update process requires both the top and bottom boards be flashed A minor tweak is made to the steps nor mally used to update both boards When this tweak is made the normalprocedure becomes the SpecialProcedure to Update Firmware 1 First go to t...

Страница 98: ...onto the top board B 1 2 If An Error Occurs If an error occurs during the Firmware Update Procedure it did not finish Perform the steps below to complete the pro cess 1 Reset the sensor Either power cycle it remove power wait at least 10 seconds apply power wait 30 seconds or click the Reset System button if you re on the sensor s Firmware Update Complete screen or can get to the sensor s System p...

Страница 99: ...wings and diagrams of mechanicalassemblies High resolution versions may be accessed on the Velodyne LiDAR web site C 1 Interface Box Mechanical Drawing 100 C 2 VLS 128 Mechanical Drawing 101 C 3 VLS 128 Optical Keep Out Zone 102 Appendix C Mechanical Diagrams 99 DRAFT ...

Страница 100: ...C 1 Interface Box Mechanical Drawing Figure C 1 Interface Box Mechanical Drawing 50 1483 Rev 1 100 VLS 128 User Manual DRAFT ...

Страница 101: ...C 2 VLS 128 Mechanical Drawing Figure C 2 VLS 128 Mechanical Drawing 86 0137 REV A Appendix C Mechanical Diagrams 101 DRAFT ...

Страница 102: ...C 3 VLS 128 Optical Keep Out Zone Figure C 3 VLS 128 Optical Keep Out Zone 86 0137 REV A 102 VLS 128 User Manual DRAFT ...

Страница 103: ...x provides technicalwiring and schematic drawings and diagrams High resolution versions may be accessed on the Velodyne LiDAR web site D 1 Interface Box Wiring Diagram 104 D 2 Interface Box Schematic 105 Appendix D Wiring Diagrams 103 DRAFT ...

Страница 104: ...D 1 Interface Box Wiring Diagram Figure D 1 Interface Box Wiring Diagram 86 0107A 104 VLS 128 User Manual DRAFT ...

Страница 105: ...D 2 Interface Box Schematic Figure D 2 Interface Box Schematic 69 8230A Appendix D Wiring Diagrams 105 DRAFT ...

Страница 106: ...ayback pre recorded data stored in pcap Packet Capture files Note VeloView does not support pcapng files VeloView displays distance measurements from a Velodyne LiDAR sensor as point data It supports custom colored dis play of variables such as intensity of return i e calibrated reflectivity time distance azimuth and laser ID The data can be exported as XYZ data in CSV format Functionality and fea...

Страница 107: ...r com downloads html software 2 Click the VeloView Download button to go the officialVeloView download page 3 Scrolldown to the How to Obtain section 4 Choose the correct binary installer for your operating system click the link 5 Save the executable installer to disk 6 Launch the installer and follow the on screen instructions E 3 Visualize Streaming Sensor Data 1 Setup access to your sensor over...

Страница 108: ... and closes the pcap file Note Velodyne LiDAR sensors generate a lot of data See Sensor Specifications on page 90 for data rates The pcap file can become quite large if the recording duration is lengthy Also it is best to record to a fast localHDD or SSD not to a slow subsystem such as a USB storage device or network drive E 5 Replay Captured Sensor Data from PCAP File To replay or examine a pcap ...

Страница 109: ...VeloView should display frame 0 Figure E 4 VeloView Play Button 4 Press Play to replay pause the data stream Use the Scrub slider tool it looks like an old fashioned volume slider to move back and forth through the data frames Both controls are in the same toolbar as the Record button 5 To take a closer look at some data scrub to an interesting frame and click the Spreadsheet button Appendix E Vel...

Страница 110: ...lbe familiar You can change column widths by dragging the column header divider left or right and by double clicking them Drag column headers left or right to reorder them Sort the table by clicking column headers And you can make the table itself wider by dragging the table s sides left or right Make Points_m_XYZ wider to expose the XYZ points themselves Figure E 6 VeloView Data Point Table 7 Cli...

Страница 111: ...empty 8 Click the Select All Points tool This turns your mouse into a point selection tool Figure E 8 VeloView Select AllPoints 9 In the 3D rendered data pane use your mouse to draw a rectangle around a smallnumber of points They will immediately populate the data table Appendix E VeloView 111 DRAFT ...

Страница 112: ...ted on the right In this example most of their intensity values exceed 110 indicating something retro reflective is there see Calibrated Reflectivity on page 31 for details Azimuth is in hundredths of a degree Distances are with respect to the sensor s origin At any point you can save a subset of data frames by doing File Save As Select Frames 112 VLS 128 User Manual DRAFT ...

Страница 113: ...e The source of each laser pulse in the sensor is a semiconductor laser diode The laser diode is a series of stacked p n junc tions similar at least in concept to that shown in Figure F 1 below When a current is applied across the junction photons are produced and routed out one end to form a tightly focused laser beam Note The physics of laser diodes can be found elsewhere on the Internet Start b...

Страница 114: ...ribing a laser pulse hitting a target in reality the sensor s laser spot is a smallrectangular area comprised of three smaller bars or bands of light as shown in Figure F 2 below The long axis of the rectangle coincides with the direction of the laser scan Figure F 2 Laser Spot Shape F 2 2 Laser Scan Pattern The gap between scan lines can be calculated with the following equation Equation F 1 Gap ...

Страница 115: ...ily grows larger The angular measure of this increase in beam path diameter is called Beam Divergence VLS 128 beam divergence on the horizontalaxis i e along the direction of the laser scan differs from beam divergence on the verticalaxis transverse to the scan by roughly a factor of two Horizontal Beam Divergence Vertical Beam Divergence 3 0 mrad 0 18 deg 1 5 mrad 0 09 deg Table F 1 VLS 128 Beam ...

Страница 116: ...MEA sentence GPS Qualifier The new options shown below in their default positions can be found on the Configuration tab in the sensor s Web Inter face Figure G 1 Web Interface PPS and GPS Qualifier Option Selections G 2 Background Your sensor maintains a counter representing the number of microseconds since the Top Of Hour TOH The TOH count is incremented based on an internaloscillator When the se...

Страница 117: ...fix and begins using its own internal time to drive the PPS reference New controloptions PPS Qualifier and GPS Qualifier described below have been added to allow the user to finely adjust the manner in which the sensor reacts when a valid PPS is confirmed and locked onto G 3 PPS Qualifier The three settings described below and in Logic Tables on the next page controlhow the sensor adjusts the TOH ...

Страница 118: ...mines if the minutes and seconds component of the TOH counter are adjusted to the timestamp provided by the GPS receiver or driven by the rollover of the sub second counter If the Require GPS Receiver Valid is On the minutes and seconds field in the NMEA sentence timestamp is used to adjust the minutes and seconds component of the TOH counter only when GPS receiver indicates a valid status If the ...

Страница 119: ...e G 4 Minutes and Seconds Counter Behavior Note If no NMEA sentence is provided the Minutes and Seconds counter is driven by the rollover of the sub seconds counter Appendix G Time Synchronization 119 DRAFT ...

Страница 120: ... The sensor then adjusts its timing such that it initiates a fir ing sequence at the phase lock offset specified by the user For example assume the user enters an angle of 35 α as the phase offset The red arrow in Figure H 1 below indicates the laser firing direction precisely as the sensor receives the rising edge of the PPS signal Note For Phase Lock to work correctly the sensor s RPM must be se...

Страница 121: ...set is presented in degrees The accuracy of the offset is 5 subject to change Figure H 2 Configuration Screen Phase Lock H 1 2 Application Scenarios When setting the phase lock offset for two or more sensors Velodyne recommends the sensors be configured to fire at each other This is the optimalconfiguration for minimizing interference because the location of the interference is under user control ...

Страница 122: ...nd aft positions the phase offsets are set to 180 and 0 as shown in Fig ure H 4 below Figure H 4 Fore and Aft Sensor Phase Offset In both scenarios the two sensors create data shadows behind each other To avoid any spurious data due to blockage or reflections from the opposing sensor the user should ignore any data in the shadowed azimuth ranges as shown in Figure H 5 on the facing page To do that...

Страница 123: ...termine for each sensor the azimuthalangles at which the shadows begin and end Then using each sensor s Web Interface or curlcommands or equivalent programmatic commands configure the sensor s horizontalFOV start and end angles See Configuration Screen on page 68 and Set Field of View on page 82 for more H 3 Status No version of VLS 128 firmware has been released yet Below are notes on pre release...

Страница 124: ...Release 5 0 6 0 of the firmware appears to have trouble with GPS and PPS Since PPS is required for Phase Lock Phase Lock isn t usable 124 VLS 128 User Manual DRAFT ...

Страница 125: ...the Sensor CAUTION READ THROUGH THIS ENTIRE SECTION BEFORE CLEANING YOUR VLS 128 SENSOR Improper handling can permanently damage it I 1 1 Required Materials 1 Clean microfiber cloths 2 Mild liquid dish washing soap 3 Spray bottle with warm clean water 4 Spray bottle with warm mildly soapy water 5 70 isopropylalcohol Method 2 ONLY 6 NACL Precision Optics Cleaner Method 3 ONLY Optional 7 Simple Gree...

Страница 126: ...apy water and a clean microfiber cloth to gently wipe the sensor again taking care not to abrade the surface When cleaning the ring lens wipe gently along the curve of the sensor not top to bottom To finish spray the sensor with clean water to rinse off any remaining soap then dry with another clean microfiber cloth I 1 4 Method Two This sensor s ring lens is made of polycarbonate and may be clean...

Страница 127: ...imple Green and distilled water to remove particulates on the lens with a rinsing action After heavy particulates are removed additionalSimple Green solution and a soft microfiber cloth can be used gently to clean the lens This should then be followed up with a 99 IPA IsopropylAlcohol wipe using a microfiber cloth to remove any residualSimple Green Never use an ammonia based cleaner Appendix I Sen...

Страница 128: ...IP address is set at the factory to 192 168 1 201 By default the sensor sends UDP data packets to broadcast address 255 255 255 255 Note Each sensor has a unique MAC Address and SerialNumber set at the factory by Velodyne LiDAR that cannot be changed J 1 2 Establishing Communication via Ethernet The instructions below are for Windows computers For linux or Macintosh computers perform equivalent st...

Страница 129: ...J 2 Network Considerations Your application network topology may be simple with a single sensor transmitting data on a basic network Or it could be complicated with multiple sensors This section presents certain topics to consider J 2 1 Throughput Requirements When actively sensing its environment your sensor produces a lot of data which it transmits via Ethernet The volume of data depends partly ...

Страница 130: ...tion IP address to a specific non broadcast IP address However two or more sensors may share the same destination address The scenarios below illustrate the wrong way and then a better way to configure them An alternative would be to direct connect sensors to separate NICs J 2 3 1 Multiple Sensors Transmitting to a Broadcast Address If multiple sensors on a network transmit data to a broadcast add...

Страница 131: ...to transmit their data to a non broadcast address If every sensor in the same network transmits packets to a specific non broadcast destination address doesn t have to be the same one as illustrated in Figure J 4 below the other sensors willnot suffer unnecessary network overhead Figure J 4 Multiple Sensors Proper Network Setup Appendix J Network Configuration 131 DRAFT ...

Страница 132: ...dquarters Velodyne LiDAR Inc 5521 Hellyer Ave San Jose CA 95138 U S A www VelodyneLiDAR com Phone 1 408 465 2800 Fax 1 408 779 9227 Emaillidar velodyne com VLS 128 User Manual 63 9483 Rev A Updated 2018 09 12 DRAFT ...

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