Validation

How to validate whether your distance reading is accurate

Reading Validation

The AM Lidar provides multiple pieces of data with each measurement. To ensure your robot is making decisions based on reliable information, it is important to validate each reading before using it.

This section explains how to determine whether a measurement should be accepted or rejected.

Overview

Each measurement includes:

• Distance (mm)

• Status Code

• Peak Signal Strength

• Ambient Light Level

A reading is considered reliable when:

• The sensor successfully completed the measurement

• The returned signal is strong enough

• The measurement is not dominated by noise

Step 1: Check Status Code

The first and most important check is the status code.

Status	Meaning	Action
0	Range Valid	✅ Continue validation
1	Sigma Fail	❌ Reject
2	Signal Fail	❌ Reject
4	Phase Fail	❌ Reject
5	Hardware Fail	❌ Reject
7	Wrap Target	✅ Continue validation (Weak)
8	Processing Fail	❌ Reject

👉 Only proceed if Status = 0 or 7

Status code 0 data should be trusted more than status code 7 data.

Wrap Target indicates the device is near the limits of what the current tuning allows or the measurement is near 4 meters. Step 2: Check Signal Strength

The Peak Signal represents how strong the reflected laser signal is.

• Higher values = stronger, more reliable readings

• Lower values = weak or distant targets

Recommended Threshold:

Peak Signal > 150 (centi-MCPS)

Peak Signal	Interpretation
> 300	Excellent
150–300	Good
< 150	Weak ⚠️

👉 Reject readings with very low signal unless necessary

Step 3: Check Ambient Light

The Ambient value represents background light/noise.

• Lower values = cleaner measurement

• Higher values = more interference

General Guidance:

Ambient < 100 (centi-MCPS) → Ideal

High ambient light can reduce measurement accuracy, especially at long range.

Step 4: Evaluate Signal-to-Noise Ratio (SNR)

The most important quality metric is:

SNR = Peak Signal / Ambient

This compares the useful signal to background noise.

Recommended Threshold:

SNR > 1.5 → Acceptable
SNR > 2.0 → Good

SNR Value	Interpretation
> 2.0	Reliable ✅
1.5–2.0	Usable ⚠️
< 1.5	Unreliable ❌

✅ Final Acceptance Criteria

A measurement should be accepted if:

• Status == 0 or 7

• Peak Signal > 150

• SNR > 1.5

Otherwise, it should be rejected or treated with caution.

⚠️ Notes and Best Practices

• A reading marked “Range Valid” may still be noisy

• Long-range measurements naturally have lower signal strength

• Highly reflective or angled surfaces may affect readings

• Bright environments increase ambient noise

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🧪 Practical Tip

When tuning your system:

• Watch how Peak Signal and Ambient change with distance

• Identify thresholds that work for your specific robot and field conditions

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🎯 Summary

Check	Requirement
Status	Must be 0
Peak Signal	> 150 recommended
SNR	> 1.5

👉 Use all three checks together for best reliability