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According to a report published by GlobeNewswire on October 1, 2024, the global LiDAR market is expected to be valued at USD 2.37 billion in 2024. It is expected to grow to approximately $13.74 billion by 2033, at a compound annual growth rate (CAGR) of 21.56% from 2024 to 2033. As LiDAR becomes an integral part of self-driving cars, robotics, and innovative infrastructure, designing the correct harness is critical to system reliability, signal fidelity, and field maintainability.
Understanding Harness Design
Lidar harnesses integrate power, high-speed data, and timing synchronization in a single cable assembly. Poor isolation of these domains can result in signal crosstalk, ground loops, or power spikes, any of which can disrupt depth measurements and jeopardize safety. Effective design begins with a functional partitioning diagram and then layers environmental, electrical, and mechanical requirements.
Functional Partitioning
- Power vs. Data vs. Sync: Keeps battery and ignition power leads physically isolated from Gigabit Ethernet pairs and GPS/trigger lines to minimize electromagnetic coupling.
- Overmolding Strategies: Romtronic’s mixed-signal overmold encapsulates both power and data leads in a single jacket, while maintaining separate internal partitions, thereby simplifying installation without compromising performance.
System Interfaces
Most automotive LiDAR units (e.g., Ouster OS1, OS2) use IP-rated RJ45 jacks (for 1000BASE-T1 data) and 6-pin JST SH/SR connectors (for power and GPS synchronization). The harness should accommodate both in a slim housing and meet the sensor’s specified bend radius requirements to maintain an IP rating.
Environmental & Mechanical Robustness
Wiring harnesses for autonomous LiDAR must be able to withstand extreme temperatures, humidity, dust, and constant vibration during vehicle use.
ISO 16750 Compliance
ISO 16750 (“Road vehicles – Environmental conditions and testing of electrical/electronic equipment”) specifies tests for electrical loads, mechanical stresses, climatic, and chemical exposure. According to ISO 16750-2/-3, LIDAR harnesses shall pass load surge, reverse voltage, vibration, and salt spray tests.
LV124 Reliability Testing
The LV124 (VW80000) outlines reliability testing for 12 V systems, including thermal shock, dust ingress, and IPX0-IPX6K water spray protection. Overmolded strain relief and composite braid help meet these stringent standards, ensuring that connectors and cables remain intact under real-world conditions.
EMI/EMC Mitigation & Simulation
Lidar photodetectors operate with microamp currents and are highly susceptible to electromagnetic interference (EMI) and radio frequency interference (RFI).
- Early-Stage Simulation: Predict coupling in complex harness geometries by modeling braid shielding, foil shielding, or hybrid shielding in a variety of frequency bands using 3D EMI tools such as FEKO.
- Shielding & Grounding: Wrap data pairs in foil-based polymer tape or stainless steel mesh, then terminate the shielding at individual chassis grounding points to prevent ground loops
Connector & Cable Selection
Connector and conductor selection affect signal integrity, sealing, and longevity.
- Automotive Ethernet: Adopt OPEN Alliance TC9–compliant STP cables ( impedance: 100 Ω ± 5%) for 1000BASE-T1, ensuring controlled impedance over –40 °C to +125 °C.
- Connector Durability: Specify RJ45 jacks rated IP67 (> 100 mating cycles) and silicone-sealed JST housings. Romtronic’s precision crimp and overmold processes deliver consistent impedance and robust retention.
Signal Integrity & Data Transmission
High-resolution LiDAR modules stream multi-gigabit data, demanding low-loss, controlled-impedance framing.
- Differential Pairs: Maintain a 100 Ω differential impedance (±5 Ω) through cable selection and PCB interface.
- Stub Minimization: Limit branch leg lengths and place mid-line junctions close to sensors to reduce reflections. Collaborate with PCB teams to align harness and transceiver impedances from the design phase onward.
Remote Diagnostics & OTA Updates
Connected vehicles demand proactive harness monitoring and firmware flexibility.
- Ethernet-to-Edge: Zonal architectures enable remote diagnostic commands and over-the-air functional upgrades via automotive Ethernet.
- Embedded Test Points: Integrate micro-TDR or spring-loaded contacts within overmolds to facilitate on-vehicle cable integrity checks without disassembly.
Modular & Serviceable Architecture
Field serviceability reduces downtime and maintenance costs.
- Segmented Builds: Divide the harness into sensor pigtails, mid-line junction boxes (IP67), and vehicle bulkheads—swap only faulty segments.
- Inline Diagnostics: Romtronic can embed test-point modules directly in the jacket, enabling live TDR scans or voltage checks without disconnecting harnesses.
Thermal Management & Lightweight Design
Prevent heat build-up around LiDAR optics while minimizing added mass.
- Reflective Sleeving: Apply Therm-L-Wrap™ self-wrapping aluminum-laminated sleeving near hot zones to reflect radiant heat and withstand convective soaks up to +200 °C.
- Slim Jackets: Utilize halogen-free, aramid-reinforced jackets and composite braids to strike a balance between mechanical protection and weight savings, essential for drones and electric vehicles.
Conclusion & Call-to-Action
By adhering to ISO 16750 and LV124 standards, utilizing EMI simulation, selecting automotive-grade Ethernet components, and integrating diagnostics, your harnesses will ensure that your autonomous LiDAR system remains accurate and reliable. Ready to enhance your next LiDAR project? Contact Romtronic today for a custom consultation on precision overmolding, integrated test point design, and complete harness validation.
Alex Wang is the Marketing Manager at Romtronic, holding a degree in International Business. With 7 years of sales experience in the electronic cable and harness industry, he oversees marketing efforts across North and South America. He deeply understands the industry and excels in market analysis, providing tailored advice to help clients better plan their purchasing and sales strategies.
