watonomous.github.io

  1. Electrical Division
  2. Electrical Division Home
  3. Radar Driver Group

[ Electrical Division : Radar Packet Structure ]

Created by [ Rowan Dempster], last modified by [ Frank Yan] on Apr 24, 2020


Table of Contents

Document Overview

The radar packet structure is outlined in the ARS430_Ethernet_Interface spreadsheet. This is available on the AutoDrive site after completing the onboarding NDAs. Anything requiring more explanation on this page can be found by looking in the AutoDrive site.

[]{.aui-icon .aui-icon-small .aui-iconfont-info .confluence-information-macro-icon}

[NOTE:] This information is still being explored, so feel free to make amendments and corrections.

Radar Packets

Packet Types

The main types of packets we deal with are Rx and Tx packets. Rx are packets the radar receives, so ones we send it for configurations. Tx packets are packets the radar transmits to us. The Tx packets will contain the necessary object data. The Tx packets can be either SensorStatus or Radar Detection packets. The radar packet is defined as such:

Radar Packet

Header           header
uint8            EventID
uint32           TimeStamp
uint32           MeasurementCounter
float32          Vambig
float32          CenterFrequency
RadarDetection[] Detections

Radar Detection Packets

The Radar Detection packets can come from either the near or far scans. The distinction is indicated by the serviceID and event ID parameters. The near scans provide a wider FOV and shorter range (+- 75 deg, up to ~70m), whereas far scans provide smaller FOV but larger range (+- 9 deg, up to ~250m). The radar will do both scans, package all the detections into groups of 30 packets, and fire them off to us. All radar detection packets have a serviceID of 220, with eventIDs ranging from 1 to 5 based on if it's using the near or far scans. The detection packet is composed of:

Radar Detection

float32     posX
float32     posY
float32     posZ
float32     VrelRad
float32     AzAng0
float32     AzAng1
float32     ElAng
float32     RCS0
float32     RCS1
float32     RangeVar
float32     VrelRadVar
float32     AzAngVar0
float32     AzAngVar1
float32     ElAngVar
float32     SNR
float32     Range
float32     Prob0
float32     Prob1
uint8       Pdh0

Sensor Status Packets

The SensorStatus packets have a ServiceID of 200, and an eventID of 0. These contain diagnostic information about the state of the radar such as temperature, voltage, and displays any alarms we should take note of. It is not of any use to perception, so we do not publish it. We just use it in our driver to check for alarms.

\

Document generated by Confluence on Nov 28, 2021 22:40

Atlassian