ADASIS v2 review

Introduction

These day I have been reading ADASIS_v2_Specification. As a matter of fact, ADASIS_v3 was already out there. So why do I have to read ADAS_v2 ? Only my mentor Roger knows.
Below is my general review towards ADASIS_v2_Specification, just as a note for myself.

main entities of ADAS applications

ADAS Horizon Provider #地平线提供者
ADAS Protocol #传输协议
ADAS Application #ADAS应用
- ADAS Resconstructor #数据重构（ADAS Horizon -> Client side）

电子地平线（Electric Horizon）是一种为车辆提供超视距道路交通信息的产品或者服务，例如超出传感器感知范围的道路（如曲率、坡度）、车道（如车道线形状、车道属性）、红绿灯（如位置、轮廓）信息。

ADASIS Concept

Digital Map Database

road networks contain:

Links (only care those ahead of the vehicle)
Nodes (define connectivity between links)

Path

Paths are built from databasse links and their connectivity. (single entity)

Paths contain characteristics, such as crossings, road attributes and so on.

Optimized Path Representation

Main Path -> First-Level Sub-Path -> Second-Level Sub-Path

Blocks

Paths are identify by path identifier (6 bits available)

Stub marks the start of a (sub-)path and it is located on another (parent) path

Profile refers to characteristics of paths

Stubs and profiles are defined by path identifier and an offset along that path.

offset is the distance between an entity and the start of a path

Vehicle status: position in respect to the Av2 Horizon and other characteristics (such as speed and heading)

Offsets

the position of map entities and the vehical position is defined by the path identifier and the distance from the start of path–Offset

13 bits available

Profile

Characteristic of a path that has a defined value.

Attributes:

Profile Type
Profile Interpolation Type #插值
Profile offset #偏置
Profile Spot

Typical examples:

Road curvature
Road heading

Stub

indicates the start of a new path that has origin at an existing one.

Value 5: used for systems with very low bandwidth or storage capacity…
Value 6: provides information for the continuation of the main path such as TURN ANGLE and RELATIVE PROBABILITY.
Value 8 to 63: Normal STUB message

Segment

specifies the most important attributes of a part of the path.

Guidelines and Recommendations

Maximum horizon trailing length

behind the current vehicle position

ADASIS v2 Mini

Only a SEGMENT message with a PATH INDEX of 4 describes the attributes of the link where the vehicle is currently located is sent.

Message Priority

POSITION message can have a higher CAN id than the STUB message, so as to achieve better consistency of positioning.

QUESTIONS to be addressed

CAN bus: multyplexing (polymorphism)
CAN layout