ADAS Parameter Definitions

Last updated
Save as PDF
Share
1. Share
2. Tweet
3. Share

Vehicle Separation Measured Parameters

The following tables provide a list of channels capable of being calculated in each vehicle within an ADAS test.

For 1 Vehicle Target testing, Racelogic refers to each vehicle as the ‘Subject Vehicle’ or the ‘Target Vehicle’. For example, under testing for adaptive cruise control, the lead vehicle will be the Target Vehicle, whilst the following vehicle (where the adaptive cruise control is being tested) is referred to as the Subject Vehicle.
For 2 Target Vehicle testing, channel naming now changes such to indicate channels calculated with respect to, Target Vehicle 1 and Target Vehicle 2. As there are now three vehicles involved with this testing, the number of channels increases at the Subject Vehicle, this is reflected in the table below:

The vehicle separation channels calculated at the Target vehicle are essentially exactly the same as the channels calculated at the subject vehicle, except for the channels highlighted in yellow.

The channels highlighted in grey are not used in Static Point testing. These are listed to ensure continuity of the Racelogic report generator application, which uses channel ordering as its sort function.

Channel name definition. Where the channel name is not obvious, then it is made up of three parts:

channel_def (1).png

The first part is the parameter type i.e. LngR = Longitudinal Range
The second part indicates which vehicle heading is being used in the calculation of this parameter i.e. sv = subject vehicle
The last part indicates which vehicle is parameter is being calculated with reference to, i.e. tg1 = Target Vehicle 1

Name		Channel Description	Units
Target 1	Target 2	Channel Description	Units
Range_tg1	Range_tg2	Direct Distance between Subject and Target vehicle	m
LngRsv_tg1	LngRsv_tg2	Longitudinal distance between the Subject and Target Vehicles measured in the direction of the Subject Vehicle heading	m
LatRsv_tg1	LatRsv_tg2	Lateral distance between the Subject and Target Vehicles measured at right angles to the Subject Vehicle heading	m
LngRref_tg1	LngRref_tg2	The longitudinal difference between the Subject and Target Vehicles based on the heading of the test track	m
LatRref_tg1	LatRref_tg2	The lateral difference between the Subject and Target Vehicles based on the heading of the test track	m
T2Csv_tg1	T2Csv_tg2	Time to Collision with Target Vehicle derived from LngRsv-tg1 and LngSsv–tg1 channels	s
T2C2sv_tg1	T2C2sv_tg2	Time to Collision with a decelerating Target Vehicle derived from the LngRsv-tg1, LngSsv-tg1 and Accel-tg1 channels	s
RelSpd_tg1	RelSpd_tg2	The relative speed between the Subject and Target Vehicles	km/h
LngRtg-tg1	LngRtg-tg2	Longitudinal distance between the Subject and Target Vehicles measured in the direction of the Target Vehicle heading	m
LatRtg-tg1	LatRtg-tg2	Lateral distance between the Subject and Target Vehicles measured at right angles to the Target Vehicle heading	m
Angle_tg1	Angle_tg2	Angle to the Target Vehicle with respect to the heading of the Subject Vehicle	°
Latdif_tg1	Latdif_tg2	The difference between Subject Vehicle and Target Vehicle latitude	min
Lngdif_tg1	Lngdif_tg2	The difference between Subject Vehicle and Target Vehicle longitude	min
Spd_tg1	Spd_tg2	Target Vehicle course over ground speed	km/h
Spd_sv	N/A	Subject Vehicle course over ground speed	km/h
Accel_tg1	Accel_tg2	Target Vehicle acceleration calculated from Target Vehicle speed and time	g
LngSsv_tg1	LngSsv_tg2	The speed between the Subject and Target Vehicles in the longitudinal direction, with respect to Subject vehicle heading	km/h
LatSsv-tg1	LatSsv_tg2	The speed between the Subject and Target Vehicles in the lateral direction, at right angles to the Subject vehicle heading	km/h
Status_tg1	Status_tg2	The DGPS status of the Target vehicle VBOX	N/A
Status_sv	Status_sv	The DGPS status of the Subject vehicle VBOX	N/A
LkTime_tg1	LkTime_tg2	Rolling time sent over 2.4 GHz Radio Link, used to indicate the quality of radio link between vehicles	N/A
LkTime_sv	N/A	Rolling time sent over 2.4 GHz Radio Link, used to indicate the quality of radio link between vehicles	N/A
App_Mode	App_Mode	The current operating mode of the Subject VBOX	N/A
SepTim_tg1	SepTim_tg2	The time it would take the Subject Vehicle to travel across the Vehicle separation distance at its current speed	s
T2Ctg_tg1	T2Ctg_tg2	Time to Collision with Target Vehicle, derived from the LngRtg-tg1 and Target vehicle long range speed	s
Yawdif_tg1	Yawdif_tg2	This angle is the difference between subject and target vehicle headings	°
YawRat_tg1	YawRat_tg2	YAW rate of the Target vehicle, only available when an IMU is connected to the VBOX in the target vehicle	°/s
Pntsv_tg1	Pntsv_tg1	The current Subject vehicle contact point being referenced in the Subject to target vehicle ADAS calculations	N/A
Pnttg1_sv	Pnttg2_sv	The current Target vehicle contact point being referenced in the Subject to target vehicle ADAS calculations	N/A

A number of the parameters shown in the table above are outlined in schematics below in order to give a clear visualisation of how they are calculated.

LngRsv_tg1,tg2; LatRsv_tg1,tg2

Longitudinal and Lateral Range with respect to subject vehicle heading.

Lng Range and Lat Range between Subject Vehicle and Target 1 Vehicle using Subject Vehicle heading example

Note: The LngRsv and LatRsv values are calculated from offset points on each respective vehicle. Details of how to apply these offsets is provided in the Quick Start Guide.

LngRref_tg1,tg2; LatRref_tg1,tg2

Longitudinal and lateral difference between two vehicles based on an external reference heading.

It is a requirement of the National Highway Traffic Safety Administration “Forward Collision Warning System NCAP Confirmation Test March 2012” confirmation tests that the Subject Vehicle (SV) remains within 0.6 m of the centre line of the Target Vehicle (in the standard referred to as Principle Other Vehicle - POV).

3 (1).jpg
Range calculations using a reference lane for NHTSA FCWS confirmation test

If this Lateral Range channel was based purely on vehicle heading then the resultant value would be extremely susceptible to noise. Small fluctuations in the Subject or Target Vehicle heading will results in fluctuations in Lateral Range greater than the NHTSA standard, the following example demonstrates this principle:

Heading fluctuation of 0.5° over a vehicle separation of 100 m:

42 (1).png

By using a Reference lane heading, a very stable Lateral Range channel is generated. Please click here for details on how to record a reference lane.

Lat Range between Subject Vehicle and Target 1 Vehicle using Reference Line heading example

LngRtg_tg1,tg2; LatRtg_tg1,tg2

Longitudinal and Lateral Range with respect to target vehicle heading.

LngRtg LatRtg.png
Lng Range and Lat Range between Subject Vehicle and Target 1 Vehicle using Target 1 Vehicle heading example

Note: Target Heading is a standard channel logged in the Target Vehicle, but only used in calculations at the Subject Vehicle.

Angle_tg1_tg2

Angle to the Target Vehicle with respect to the heading of the Subject Vehicle.

ADAS Angle.png
Angle between Subject Vehicle and Target 1 Vehicle using Subject Vehicle heading example

Time To Collision (T2C)

T2Csv_tg1,tg2

Time to collision based on Longitudinal Range from Subject Vehicle to Target Vehicle based on Subject Vehicle heading and Longitudinal Speed.

T2Csv_tg1 example:

34 (1).png

T2C2sv_tg1,tg2

Time to collision taking into account a decelerating target vehicle

NHTSA provide the following equation to account for a decelerating target vehicle in test 2 of their FCWS NCAP confirmation test.

T2C2sv_tg1 example:

V_pov = Velocity of Principle Other Vehicle (Target Speed)
V_sv = Velocity of Subject Vehicle (Speed)
a_pov = Acceleration of Principle Other Vehicle (Target Accel)
a_sv = Acceleration of Subject Vehicle (Accel)
S_sv= Longitudinal distance from Subject Vehicle to Target Vehicle (LngRange)

T2Ctg_tg1

Time to collision based on Longitudinal Range from Subject Vehicle to Target Vehicle based on Target Vehicle heading and Target Vehicle longitudinal Speed.

T2Ctg_tg1 example:

35 (1).png

LkTime_sv,tg1,tg2 (Link Time)

This channel is a time based incremental value based on Target Vehicle UTC time. A good link will show a trace incrementing every 10 ms with no drops to zero. Once this value reaches 65535 it is reset to zero.

Link Time is a good indicator of ADAS radio link quality, If this incremental count drops out and falls to zero then it is a likely indication that the ADAS radio link has intermittently failed.

The VBOX ADAS system will suffer occaisional single sample drops outs, which are acceptable but larger periods of time with full or intermittent drop outs are an indicator of a Radio problem that needs addressing.

See also section Radio Link

App_Mode

This channel indicates the current operating mode of the VBOX.

App Mode Value	Description
1	Normal
2	Target
4	Subject
8	Static
10	Lane departure - lane 1
0x50	Lane departure - lane 2
0x90	Lane departure - lane 3

SepTim_tg1,tg2 (Separation Time)

For Adaptive Cruise control testing; time it would take the Subject Vehicle to travel across the Vehicle separation distance at its current speed.

SepTim_tg1 example:

41 (1).png

3 Target Measured Parameters

The following tables provide a list of channels capable of being calculated in each vehicle within an ADAS test.

Channel name definition. Where the channel name is not obvious, then it is made up of three parts:

channel_def (1).png

The first part is the parameter type i.e. LngR = Longitudinal Range
The second part indicates which vehicle heading is being used in the calculation of this parameter i.e. sv = subject vehicle
The last part indicates which vehicle is parameter is being calculated with reference to, i.e. tg1 = Target Vehicle 1

Name				Channel Description	Units
Subject	Target 1	Target 2	Target 3	Channel Description	Units
Range_tg1	Range_tg1	Range_tg2	Range_tg3	Direct Distance between Subject and Target vehicles	m
LaneR_sv, LaneR_tg1, LaneR_tg2, LaneR_tg3	LaneR_tg1	LaneR_tg2	LaneR_tg3	Lateral distance between the vehicle antenna and the reference line measured at right angles to the reference line	m
LngRsv_tg1, LngRsv_tg2, LngRsv_tg3	LngRsv_tg1	LngRsv_tg2	LngRsv_tg3	Longitudinal distance between the Subject and Target Vehicles measured in the direction of the Subject Vehicle heading	m
LatRsv_tg1, LatRsv_tg2, LatRsv_tg3	LatRsv_tg1	LatRsv_tg2	LatRsv_tg3	Lateral distance between the Subject and Target Vehicles measured at right angles to the Subject Vehicle heading	m
LngRef_tg1, LngRef_tg2, LngRef_tg3	LngRef_tg1	LngRef_tg2	LngRef_tg3	Longitudinal distance between the Subject and Target Vehicles measured in the direction of the reference line heading	m
LatRef_tg1, LatRef_tg2, LatRef_tg3	LatRef_tg1	LatRef_tg2	LatRef_tg3	Lateral distance between the Subject and Target Vehicles measured at right angles to the reference line heading	m
Angle_tg1, Angle_tg2, Angle_tg3	Angle_tg1	Angle_tg2	Angle_tg3	Angle to the Target Vehicle with respect to the heading of the Subject Vehicle	°
Status_sv, Status_tg1, Status_tg2, Status_tg3	Status_sv, Status_tg1, Status_tg2, Status_tg3	Status_sv, Status_tg1, Status_tg2, Status_tg3	Status_sv, Status_tg1, Status_tg2, Status_tg3	The DGPS status of the vehicle VBOXs	N/A
LkTime_tg1, LkTime_tg2, LkTime_tg3	LkTime_tg1	LkTime_tg2	LkTime_tg3	Rolling time sent over 2.4 GHz Radio Link, used to indicate the quality of radio link between vehicles	N/A
LnRtg1_tg1, LnRtg1_tg2, LnRtg1_tg3	LnRtg1_tg1	LnRtg1_tg2	LnRtg1_tg3	Longitudinal distance between the Subject and Target Vehicles measured in the direction of the Target Vehicle 1 heading	m
LaRtg1_tg1, LaRtg1_tg2, LaRtg1_tg3	LaRtg1_tg1	LaRtg1_tg2	LaRtg1_tg3	Lateral distance between the Subject and Target Vehicles measured at right angles to the Target Vehicle 1 heading	m
Spd_tg1, Spd_tg2, Spd_tg3	N/A	N/A	N/A	Target Vehicle course over ground speed	km/h
TTC1_tg3	N/A	N/A	TTC1_tg3	Time for the front most contact point of Target Vehicle 3 to cross the reference line	s

A number of the parameters shown in the table above are outlined in schematics below in order to give a clear visualisation of how they are calculated.

Channels not explained below can be viewed within the Vehicle Separation Measured Parameters section above.

LaneR_sv,tg1,tg2,tg3

Lateral distance between the vehicle antenna and the reference line measured at right angles to the reference line.

LaneR diagram.png
LaneR example

LnRtg1_tg1,tg2,tg3; LaRtg1_tg1,tg2,tg3

Lateral distance between the Subject and Target Vehicles measured at right angles to the Target Vehicle 1 heading.

LnRtg1 LaRtg1.png
Lng Range and Lat Range between Subject Vehicle and Target 2 Vehicle using Target 1 Vehicle heading example

TTC1_tg3

Time to cross the reference line calculated from the front most contact point of Target Vehicle 3.

Assuming Contact Point 1 is the front most contact point:

TTC1_tg3 equation.png

Lane Departure Measured Parameters

The following table provides a list of extra channels capable of being logged in the Subject Vehicle during a lane departure warning system test.

Channel Name	Channel Description	Units
Range_FL	Lateral Distance to Line from vehicle front left point	m
Range_FR	Lateral Distance to Line from vehicle front right point	m
Range_RL	Lateral Distance to Line from vehicle rear left point	m
Range_RR	Lateral Distance to Line from vehicle rear right point	m
TTC_FL	Time To Line cross, wrt to vehicle front left point	s
TTC_FR	Time To Line cross, wrt to vehicle front right point	s
TTC_RL	Time To Line cross, wrt to vehicle rear left point	s
TTC_RR	Time To Line cross, wrt to vehicle rear right point	s
LatSpd_FL	Lateral speed toward line wrt to vehicle front left point	km/h
LatSpd_RR	Lateral speed toward line wrt to vehicle rear right point	km/h
LatSpd_RL	Lateral speed toward line wrt to vehicle rear left point	km/h
LatSpd_FR	Lateral speed toward line wrt to vehicle front right point	km/h
Angle	The Angle between the vehicle heading and the tangent of the reference lane at the point where range is calculated	°

A number of the parameters shown in the table above are outlined in schematics below in order to give a clear visualisation of how they are calculated.

Range_FL,FR,RL,RR

The value for Range is the shortest perpendicular distance between the Front Left, Front Right, Rear Right or Rear Left offset point and the surveyed lane.

range_lt calc2.png
Range_FL parameter example

range_rt cal.png
Range_FR parameter example

TTC_FL,FR,RL,RR

Time to cross the reference lane calculated from the Front Left, Front Right, Rear Right or Rear Left offset point range and lateral speed.

Front right offset example:

TTC_FR = Range_FR (m)/LatSpd_FR (m/s)

LatSpd_FL,FR,RL,RR

Lateral speed of the Front Left, Front Right, Rear Right or Rear Left offset point with respect to the marked lane edge.

Front Left offset example:

LatSpd_FL = V_fwd * Sin(α)

V_fwd= GPS velocity (course over ground)
α = Lane edge Heading – Heading at Vehicle offset point.

Angle

angle calc2.png

Angle parameter calculation

The value of Angle is the angle between the vehicle heading and the tangent of the surveyed lane at the shortest perpendicular distance to the GPS antenna.

Lane Departure Calculations Around A Curve

When testing a Lane Departure Warning System around a curved lane the VBOX firmware takes measurements from the corner position to the nearest perpendicular tangent line to the curved lane edge, as shown below.

calc_curve2 (1).png

Determining range from a curved lane

Multi Static Point Measured Parameters

The following table provides a list of extra channels capable of being logged in the Subject Vehicle during a multi static point test.

Channel Name	Description	Units
ID (1-5)	The point number of the feature currently occupying ID 1/2/3/4/5	N/A
Range (1-5)	The direct distance between the measurement point and the feature in ID 1/2/3/4/5	m
Lat_Range (1-5)	The Lateral distance between the measurement point and the feature in ID 1/2/3/4/5 measured at right angles to the subject vehicle's heading	m
Lng_Range (1-5)	The Longitudinal distance between the measurement point and the feature in ID 1/2/3/4/5 measured in the direction of the subject vehicle's heading	m
Angle (1-5)	The angle to the feature in ID 1/2/3/4/5 with respect to the subject vehicles heading	°