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ADAS Parameter Definitions

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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 testing) 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
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.
 

LngRsv LatRsv.png
Lng Range and Lat Range between Subject Vehicle and Target 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.


adas_angle (1).png
Lat Range between Subject Vehicle and Target 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 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 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:

t2c2sv-tg1 (1).png
 

  • Vpov = Velocity of Principle Other Vehicle (Target Speed)
  • Vcv = Velocity of Subject Vehicle (Speed)
  • apov = Acceleration of Principle Other Vehicle (Target Accel)
  • Ssv = 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
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_tg1LnRtg1_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_tg1LaRtg1_tg2LaRtg1_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 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 = Vfwd * Sin(α)

  • Vfwd = 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 °