Definition
The Add-On DELTA calculates relative distances, velocities and angles between the Hunter vehicle and up to five Target vehicles in view of the Hunter coordinate system. There are two different Delta calculations:
• Delta 1:1: Driving robots are using the DELTA data relating to one specific target for driving control. For this, the Delta 1:1 data stream can be output simultaneously to the Delta 1:5 data stream.
• Delta 1:5: More complex testing scenarios require multiple target vehicles. Therefore, the ADMA provides an additional data stream that contains the DELTA data to up to five Target vehicles.
Requirements
For using the Add-On Delta function, a license and at least two ADMA systems are required:
• one in the Hunter vehicle (called DELTA-ADMA) and
• one in the Target vehicle (called EGO-ADMA) and
• optionally up to four other Target vehicles equipped with an ADMA
Note: For being authorized using DELTA Data a License is required in the Hunter ADMA.
DELTA Data Output
The coordinate system of the Hunter defines the coordinate system for the DELTA data. The INS Yaw describes the longitudinal direciton (x direction) of the Hunter vehicle. All relative angles relate to this axis. The ISO (DIN70000) coordinate system is applied to all DELTA data and relates to the configured POI in Hunter and Target. The data output rate is fixed to 100 Hz.
Integrated Data
The DELTA data stream contains the following DELTA channels:
• delta Longitudinal
• delta Lateral
• Distance (sum vector of delta Latitude and delta Longitude)
• delta Velocity
• Angle of Orientation (Yaw-Delta-ADMA – Yaw-Ego-ADMA)
And the following EGO-ADMA and Delta-ADMA Data:
• Forward Velocity
• Lateral Velocity
• Forward Acceleration
• Lateral Acceleration
• Pitch Angle
• GNSS Mode
• Lateral Position
• Longitudinal Position
DAQ Integration
If multiple Targets are used, the ADMA outputs the Delta 1:5 data stream multiple times. In this case, the DAQ receives the data stream by Source IP and Source Port but needs to filter the data packets by “Target SN” that is included in the data packets.
The last three digits of the target SN are output as HEX from byte 24, after which the data can be filtered.
Schematic ADMA Delta data synchronization
The latency of the Delta data depends on the WiFi delay. In best case scenario the latency can be 10 milliseconds, but in the most situations under real circumstances, the latency varies between 15 and 40 milliseconds. The data of both ADMA systems get synchronized from the hunter ADMA as soon as the remote data of the Ego ADMA arrive.
Wiring Hunter ADMA
The following diagram shows an example wiring of the Hunter ADMA.
Wiring Target ADMA
The following diagram shows an example wiring of the Target ADMA.
DELTA 1:1 Configuration
Network configuration
The ADMA Systems communicate via UDP. The ADMA uses datagram sockets to establish host-to-host communications. An application binds a socket to its endpoint of data transmission, which is a combination of an IP address and a service port.
A port is a software structure that is identified by the port number, a 16 bit integer value, allowing for port numbers between 1024 and 65535. For each data stream different service ports have to be used.
Source IP/Port number:
This field identifies the IP/Port of the sending system.
Destination IP/Port number:
This required field identifies the IP/Port of the receiving system.
The IP settings of the ADMA Ethernet ports can be changed in menu 2️⃣ DATA LINK. The Add-On Delta can be configured at menu 7️⃣ ADD-ONS / DELTA DATA.
DELTA 1:1 Configuration
The following diagram shows an example configuration for outputting DELTA 1:1 data, e.g. for using a driving robot at the ip address 192.168.88.121:
DELTA 1:5 Configuration
The following diagram shows an example configuration for DELTA 1:5 data output to the DAQ at the ip address 192.168.88.100:
Note: In the following Excel document you will find an overview (summary of the information above) of the standard IP-settings for the Delta Setup (1:1 and 1:5).
Point of Calculation
The DELTA Add-On calculates the delta values between the defined POI at the Hunter ADMA and POI of the Target ADMA. This allows to compare the DELTA data directly with the VUT (Vehicle under Test) sensor measurements (Hunter Vehicle).
Offset Corrections
In some cases, an offset correction of the lateral or longitudinal distance can be useful. To make a quick adjustment, user defined offset values can be added or subtracted from the lateral or longitudinal distance.
Once the point of interests has been defined, the ADMA has been initialized the correct way and RTK2 is available, the offsets can be determined automatically by using the function zero lateral / longitudinal distance.
By using the button Save setting to ADMA, the configured offset values will be stored at the ADMA without a restart of the measurement mode.
In the figures below, you will find the definition of the lateral and longitudinal offset to the defined DELTA point of interests.
Note: Using the longitudinal and lateral offsets to correct the delta measurements will only work, when both vehicles have the same orientation angle.
Lateral and Longitudinal offsets do not influence the delta resultant distance value.
CAN and Ethernet behavior in case of EGO data outage (recurrence interval)
In case of EGO data outage, e.g. when the WiFi connection between both vehicles breaks down, the Ethernet DELTA data output behavior varies from the CAN output:
• ETH outputs zeros in the DELTA data stream.
• CAN outputs the last valid DELTA value for a duration of x seconds, where x represents the specified recurrence interval.
Example 1: Configured CAN recurrence interval of 100 msec with an ego data loss over 100 msec.
Example 2: Configured CAN recurrence interval of 100 msec with an ego data loss over 150 msec.
List of data packets
DELTA 1:1 | V7.0
Please find the list of Addon DELTA 1:1 data packets in the article Delta Data – List of data packets v7.0.
DELTA 1:5 | V7.1
Please find the list of Addon DELTA 1:5 data packets in the article Delta Data – List of data packets v7.1.
