Objective Rating

Description

Objective Rating evaluates agreement between curves and a reference using ISO/TS 18571:2024 or CORA. It reports an overall rating and component ratings from 0 to 1. A higher rating means better agreement.

Select curves that measure the same physical quantity at comparable locations and in the same direction. ISO/TS 18571 applies to non-ambiguous signals.

When this feature is available

Objective Rating becomes available when the curves and settings meet the requirements:

• A manual selection or an automatic group must contain at least two instrumentation channels. A curve and the curves derived from it count as one channel.
• The source instrumentation curves must have the same measurement units.
• A selected reference curve must still be in the curve selection.
• The current numeric settings must be valid.
• The curves may come from different loaded tests.

When a requirement is not met, the button is unavailable and its tooltip gives the reason. If you deselect the reference curve, open the settings and select a new reference. Deselecting other curves does not change the reference.

For manual selection, select the curves and click Objective Rating. The hand icon shows Use Selected Curves. Select AVERAGE or one curve in Reference Signal.

For automatic selection, clear the curve selection, set Automatic grouping, and click Objective Rating. The search icon shows Find Appropriate Curves. Each group uses AVERAGE as its reference.

Settings

Setting	Default	Effect
Rating Method	ISO/TS 18571	Selects ISO/TS 18571:2024 or CORA
Reference Signal	AVERAGE	Uses the group mean or one manually selected curve
Apply Filter	On	Applies SAE J211 CFC filtering before the rating
Filter CFC	AUTO	Selects a class from instrumentation metadata; manual choices are 60, 180, 600, and 1000
Set Evaluation Interval	Off	ISO uses the common time range; CORA calculates its evaluation interval
Start Time / End Time	0.0 / 0.3 s	Evaluation interval when Set Evaluation Interval is on
Rating Grid Interval (Advanced)	Blank	Uses the method's default grid

Automatic grouping

The selected fields must match within each group. Measurement units are always required. These controls are available when the curve selection is clear.

Grouping field	Default
Sensor location	Selected
Sensor attachment	Selected
Sensor type	Selected
Sensor axis	Selected
Measurement units	Required
Vehicle number	Selected
Test number	Clear

The default permits groups across tests. Select Test number to keep tests separate. Clear a field to permit different values in one group. For example, clearing Sensor location permits curves from different locations in the same group.

Automatic filter selection

AUTO uses sensor attachment, sensor type, and measurement units to find a filter class. Every curve must resolve to one supported class, and that class must be the same for the whole group. The Filter result column shows the selected class, for example AUTO → CFC 1000. The information icon beside Filter CFC explains automatic selection.

Missing or ambiguous metadata, a failed lookup, or incompatible filter classes cause an error for that group. Completed groups remain available in the results and export. To resolve the error, check the metadata, separate curves into groups with the same CFC, or select an appropriate manual class.

AUTO also requires an existing data-provider filter to have a cutoff at or above the requested cutoff. A lower existing cutoff causes an error. Choose the filter settings appropriate for the measurements and test protocol.

Evaluation interval and rating grid

With Set Evaluation Interval off, ISO uses the time range shared by the reference and comparison curves. CORA uses its automatic interval procedure. The intervals can differ between methods or comparison curves.

To request a specific interval, turn Set Evaluation Interval on and enter start and end times in seconds. Start time must be less than end time. The calculation uses the available overlapping data. The summary shows the actual Evaluation Interval (ms).

Leave Rating Grid Interval blank to use the method's default:

• ISO uses a 0.0001 s interval (10 kHz).
• CORA starts from the coarsest input sampling interval and adjusts the grid to fit the evaluation interval.

A manual grid interval must be positive. A changed grid can change the rating. An ISO grid other than the standard setting produces a CUSTOM profile. ISO grades apply to results with the standard parameter and grid settings.

CORA parameters

The defaults are the parameters proposed for crash-test dummy responses in chapter 18 of the CORAplus 4.2.0 User's Manual. A changed CORA parameter produces a CUSTOM profile. Most of these controls are in Advanced.

Setting	Default	Effect
Reference Amplitude (Y_NORM)	Largest absolute amplitude of the reference	Sets the amplitude for corridor widths and the automatic interval search
Fixed Reference Amplitude	Blank	Supplies a positive Y_NORM in signal units when Fixed value is selected
Inner / Outer Corridor Width (a_0 / b_0)	0.05 / 0.50	Scales the corridor half-widths with Y_NORM
Inner / Outer Sigma Weight (a_sigma / b_sigma)	0 / 0	Adds a contribution from the spread of the reference curves
Corridor Exponent (k_C)	2	Controls the rating between the corridor bounds
Interval Start / End Threshold (a_start / a_end)	0.030 / 0.075	Controls the automatic interval search
Interval Expansion (d_expand)	0.010	Expands the automatically found interval
Interval End Delta (d_end)	0.200	Controls the automatic end search
Minimum / Maximum Phase Shift (d_min / d_max)	0.01 / 0.12	Fractions of the evaluation duration used for the phase rating
Minimum Overlap (K)	0.80	Sets the minimum overlap for cross correlation
Progression / Phase / Size Exponent (k_V / k_P / k_G)	10 / 1 / 1	Controls the component rating curves
Corridor / Cross Correlation Weight (w_C / w_K)	0.50 / 0.50	Combines the two main ratings
Progression / Phase / Size Weight (w_V / w_P / w_G)	0.50 / 0.25 / 0.25	Combines the cross-correlation components

With a manual evaluation interval, the default Y_NORM uses the largest absolute reference amplitude within that requested interval. With an automatic interval, it uses the reference data before the interval search narrows the range.

The CORA settings must follow these rules:

• The fixed reference amplitude must be greater than 0.
• The corridor widths, sigma weights, interval thresholds, interval expansion, end delta, phase-shift limits, and weights must be from 0 to 1.
• The inner corridor width must be less than the outer width.
• The inner sigma weight must not be greater than the outer sigma weight.
• The minimum phase shift must be less than the maximum phase shift.
• The minimum overlap must be greater than 0 and less than 1.
• The exponents are whole numbers of 1 or more. A value that is not valid uses the default.
• The two main weights must sum to 1. The three cross-correlation weights must also sum to 1.

How WebSAT processes the data

1. Load the original raw instrumentation curves. For a derived curve, use its source instrumentation curves.
2. Apply the Objective Rating filter settings.
3. Select the evaluation interval and place the curves on a common rating grid.
4. Use the selected reference curve or calculate the mean reference.
5. Calculate the method's component ratings and overall rating.
6. Report the summary, processed curves, corridors, and diagnostics.

Earlier curve operations, such as filtering, scaling, integration, or resampling, are not included. The information icon beside Curve in the summary gives this reminder. The Objective Rating filter and evaluation interval settings apply to the loaded raw curves. Original instrumentation data can contain a filter applied by the data provider.

With AVERAGE, each curve contributes to the mean reference and receives a rating against it. This is useful for repeated measurements. With a selected reference, the summary contains ratings for the other curves.

Results

Rating Summary

The summary appears before the plot. For multiple groups, use Signal group to change the displayed group. Group labels show the grouping information and curve count.

The table gives the curve, reference, overall rating, component ratings, phase shift in milliseconds and samples, evaluation interval in milliseconds, and sample count. It also shows the filter, custom profile, and grade when applicable.

Warnings appear in a box below the table. Each warning shows one time. A warning that applies to only some curves names those curves first. Warnings identify conditions such as a grid finer than the measured data or limited recorded data for the CORA phase-shift search.

Method	Components	Overall rating
ISO/TS 18571	Corridor (Z), Phase (E_P), Magnitude (E_M), Slope (E_S)	0.40 Z + 0.20 E_P + 0.20 E_M + 0.20 E_S
CORA	Corridor (C1), Cross correlation (C2), Progression (V), Phase shift (P), Size (G)	By default, 0.50 C1 + 0.50 C2; C2 is 0.50 V + 0.25 P + 0.25 G

ISO grades are excellent, good, fair, or poor with the standard parameter and grid settings.

A positive Phase Shift means the comparison curve occurs later than the reference. CORAplus reports the opposite shift sign. When comparing software results, use the same inputs, reference, filter, evaluation interval, rating grid, and method parameters.

Plot and diagnostics

Select a summary row to change the plotted comparison curve. The plot shows the processed reference and comparison curves with the inner and outer corridors used for the rating.

Expand Diagnostics to see the supporting values for the selected curve:

• ISO: maximum correlation, phase shift, magnitude error, slope error, and reference extremum.
• CORA: maximum cross correlation, phase shift, and reference amplitude.

Use these values to investigate a rating or compare calculations with other software.

Export

• Export all groups exports the completed groups using the summary's column names, order, units, and precision. When a group has warnings, the export also has a Warnings column. With multiple groups, it adds a Signal group column.
• Export diagnostics exports the supporting values for the selected curve. The file name identifies the curve.
• The plot's floppy disk icon saves the processed reference, comparison, and corridor bounds. The CSV file name includes Objective Rating, the method, and the test and curve numbers.

References

• ISO/TS 18571:2024, Road vehicles — Objective rating metric for non-ambiguous signals.
• C. Thunert, CORAplus Release 4.2.0 User's Manual, December 2025.