Radar Sensor Calibration
Radar sensor calibration ensures the accurate measurement and emission performance of automotive radar systems, supporting compliance with regulatory standards like ECE-R-10 and the Radio Equipment Directive (RED). Calibration is essential for validating sensor behavior under controlled test conditions and during type approval.
Scope and Application
Calibration applies to radar-based driver assistance systems (e.g. SRR, MRR, LRR) and is performed:
During development and integration phases
As part of pre-compliance and regulatory testing
After hardware or software changes affecting signal behavior
It ensures correct positioning, stable power output, and reliable distance detection under real and simulated conditions.
Key Technical Requirements
Radar sensor calibration addresses both performance validation and regulatory conformity. Key parameters include:
Transmitted power: Measured using a spectrum analyzer to ensure compliance with limits defined in ETSI EN 301 091 and similar standards
Angular resolution: Validated through defined target grids to verify the radar sensor’s ability to distinguish between closely spaced objects
Range accuracy: Assessed using time-of-flight measurements against calibrated static targets
Calibration is typically performed in controlled environments using tools such as radar target simulators, trihedral reflectors, and anechoic chambers.
Key Calibration Parameters
The following table provides an overview of commonly assessed calibration parameters in the context of type approval and pre-compliance testing. It also indicates their relevance in regulatory frameworks or referenced standards.
| Parameter | Standard | Test Method | Regulatory Status |
|---|---|---|---|
| Transmitted Power | ETSI EN 301 091 | Spectrum analyzer (peak power) | Mandatory (RED, ECE-R-10) |
| Angular Resolution | ISO 17387 | Trihedral reflector grid with 0.1° increments | Conditionally Required (ISO-based) |
| Range Accuracy | SAE J3086 | Time-of-flight with calibrated static targets | Optional (Performance Testing) |
Note:
- Mandatory parameters are explicitly required by legal frameworks such as the RED or ECE-R-10.
- Conditionally Required refers to parameters defined in technical standards (e.g., ISO), which may become mandatory depending on the system's function (e.g., Lane Departure Warning).
- Optional parameters are typically evaluated to demonstrate system performance but are not legal requirements.
| Parameter | Details |
|---|---|
| Transmitted Power |
Standard: ETSI EN 301 091 Test Method: Spectrum analyzer (peak power) Regulatory Status: Mandatory (RED, ECE-R-10) |
| Angular Resolution |
Standard: ISO 17387 Test Method: Trihedral reflector grid with 0.1° increments Regulatory Status: Conditionally Required (ISO-based) |
| Range Accuracy |
Standard: SAE J3086 Test Method: Time-of-flight with calibrated static targets Regulatory Status: Optional (Performance Testing) |
Note:
- Mandatory parameters are explicitly required by legal frameworks such as the RED or ECE-R-10.
- Conditionally Required refers to parameters defined in technical standards (e.g., ISO), which may become mandatory depending on the system's function (e.g., Lane Departure Warning).
- Optional parameters are typically evaluated to demonstrate system performance but are not legal requirements.
Certification and Compliance
Radar sensor calibration supports formal testing for:
ECE type approval under ECE-R-10
RED compliance for RF transmission behavior
National radio approvals (e.g., FCC, ISED, MIC, KC)
Although calibration is not a standalone certification step, it is required to ensure the accuracy and repeatability of official test results.
Lifecycle Relevance
Calibration is relevant across the entire development and approval cycle:
Development: Early verification of sensor characteristics
Pre-compliance: Preparation for formal EMC and RF testing
Type approval: Reliable sensor output during regulatory assessments
Post-modification: Recalibration after component or software updates