In the high-altitude mountainous and plateau region of western Sichuan, the terrain is deeply fragmented, with dense networks of gorges and rivers. Combined with high altitude, low temperatures, strong winds, rain, and snow, the construction of transmission optical cables faces significant challenges in route reconnaissance, cable pulling, and laying operations. Traditional manual construction methods are inefficient and expose workers to prolonged safety risks in scenarios such as crossing mountains, rivers, dense forests, and cliffs. This paper investigates the application of drone technology in the reconnaissance, pilot line pulling, and crossing operations of transmission optical cable construction. It outlines the technical workflow and key quality and safety control points, and evaluates the engineering effectiveness and conditions for widespread adoption.
1. Construction Environment and Traditional Challenges in the Western Sichuan Plateau Region
1.1 Topography and Climate Characteristics
The western Sichuan plateau region is characterized by high elevation, large relief, and deep cutting. Ridges and valleys alternate, and areas of gorges, rivers, steep slopes, and dense forests are widespread. Transmission optical cable routes often need to traverse ridges, cross river valleys, or be laid along mountain edges. The construction space is narrow, work surfaces are scattered, and the line points exhibit typical features of being “remote, dispersed, and difficult to reach.” The climate in this area is complex and variable. High altitude leads to low temperatures and hypoxia, placing higher demands on personnel stamina and equipment performance. Frequent strong winds, rain, snow, and ice further shorten the effective construction window. Sudden weather changes can easily cause work stoppages and rework. The combined effects of terrain and climate dictate that construction must prioritize safety, mobility, and organizational efficiency, as delays in key nodes can amplify schedule and risk.
1.2 Organizational Conditions and Traditional Construction Methods
When constructing transmission optical cables in the western Sichuan mountainous area, organizational conditions are constrained by factors such as transportation, material logistics, and communication support. Construction teams rely on temporary roads, mountain paths, or manual carrying to transport poles, pulleys, traction ropes, and cable reels to the work points. Equipment mobilization and personnel assembly are time-consuming, and site deployment follows a pattern of “multiple points blooming, segmented advancement.” The traditional workflow typically involves: “manual reconnaissance → ground pilot line laying → rope upgrading → optical cable pulling → fixing and protection → testing and acceptance.” For crossing sections or obstacle sections, manual detour or throwing methods are used to achieve pilot line crossing, followed by organizing traction equipment or manual pulling to complete cable laying. This method heavily depends on personnel experience and physical strength. In complex terrain, repeated route trials are required, and multiple crossing operations easily create efficiency bottlenecks on critical paths while significantly increasing the proportion of high-risk tasks.
1.3 Typical Construction Difficulties and Demand for Drone Technology
Construction in the western Sichuan plateau region exhibits three main difficulties. First, crossing ridges, rivers, and deep gorges presents challenges because personnel detour distances are long and landing points are difficult to control. The success rate of traditional pilot line laying is significantly affected by terrain and wind field. Second, areas such as dense forests, steep slopes, and cliff edges pose accessibility problems. Due to difficult ground access, material transportation and personnel movement costs are high, making “reaching the construction point” a constraint on “construction itself.” Third, low temperature and hypoxia combined with complex terrain exacerbate the contradiction between safety and progress when personnel need to climb, wade, or work at edges, increasing personnel risk. Additionally, project schedules are often tight, and pressure to meet deadlines can breed safety hazards. Based on these contradictions, the demand for drone technology in construction is mainly reflected in three aspects: using aerial flight to replace high-risk personnel crossing, thereby achieving rapid pilot line laying across crossing sections; relying on aerial photography reconnaissance and route confirmation to improve survey efficiency and accuracy; and reducing personnel exposure time in cliffs, deep valleys, and water areas, thereby enhancing efficiency while lowering safety risks while ensuring quality.
2. Drone Construction Technology Scheme and Key Process Flow
2.1 Technical Principle and Overall Scheme Design
The core of drone technology in transmission optical cable construction lies in replacing “personnel crossing” with “aerial crossing,” transforming the time-consuming and high-risk pilot line laying operation in complex terrain from ground-based to air-based, thereby forming a replicable crossing construction mode. The overall technical flow is: drone reconnaissance and route confirmation → carrying pilot line to cross obstacles and precise landing → replacing pilot line with traction rope → using ground traction system to control tension and complete cable laying → fixing, protection, and testing acceptance. In this process, the one-time crossing of the pilot line is achieved by the drone, while the controllability of tension and bending radius during cable laying is ensured by the ground traction system. The overall scheme design should focus on three aspects: first, scenario classification, covering crossing of rivers, gullies, ridges, and inaccessible forest sections; second, operational coordination, achieving integrated configuration of drone pilot, ground reception, traction operator, and quality safety personnel; third, quality and safety closed-loop, advancing control points to reconnaissance, flight, traction, and acceptance stages. Through the organizational mode of “point breakthrough, segment advancement,” the controllability and success rate of critical paths in high-altitude plateau optical cable projects can be effectively improved.
2.2 Survey, Mapping, and Flight Route Planning
The key prerequisite for drone technology construction is “accurate reconnaissance” and “reliable flight route.” During the survey and mapping phase, it is necessary to obtain information such as anchor point positions at both ends of the crossing section, crossing distance and height difference, distribution of ground obstacles, wind-sensitive areas, material assembly conditions, and personnel standing positions. This information forms image and measurement data that can be used for construction briefing. For key parts such as crossing rivers or canyons, reverse route planning should be carried out around “reachable landing points,” clearly defining the safe buffer zone for pilot line landing, recovery path, and backup landing points, to avoid the risk of the pilot line falling into tree canopies, water bodies, or rock crevices where recovery is difficult.
In the flight route planning stage, the unique meteorological characteristics of the high-altitude plateau must be considered. Specific operation time windows should be clarified, stop-fly criteria (such as wind speed, visibility, precipitation, low-temperature thresholds) should be clearly defined, and alternate landing points should be reasonably set. At the same time, the principle of “obstacle avoidance priority” must be followed in route planning, avoiding high-voltage lines, communication towers, dense canopy areas, and strong turbulence zones in narrow gorges as much as possible. Segmented routes or intermediate landing points may be used as needed to reduce flight risk. By structuring reconnaissance data (e.g., converting it into forms or drawings), the proportion of on-site ad hoc decisions can be significantly reduced, thereby laying the foundation for one-time successful pilot line laying.
2.3 Pilot Line Laying and Traction Laying Process
In transmission optical cable construction in the western Sichuan plateau, the key to drone technology lies not only in “being able to fly” but in organizing pilot line laying, rope upgrading, and cable laying into a set of executable, inspectable, and acceptable standard procedures. To ensure one-time success of crossing sections and avoid rework, the control thread should be “controllable landing, continuous channel, stable tension, adequate anti-wear protection.” The operation is broken down into quantifiable process stages and control points, facilitating on-site briefing, process traceability, and quality tracing. Based on this, the following standard process and key control points table is established.
| Process Stage | Main Tasks | Key Inputs / Equipment | Key Control Points (Quality / Safety) | Process Outputs |
|---|---|---|---|---|
| 1) Operation Preparation | Work briefing, station layout, communication setup, risk isolation | Walkie-talkie / phone, warning tape, work briefing form, weather assessment | Define stop-fly threshold and evacuation command; delineate forbidden entry line for traction area; confirm both ends of ground reception personnel are in place | Operation condition confirmation record, station layout diagram |
| 2) Drone Loading and Takeoff | Pilot line loading, anti-tangle handling, pre-flight inspection | Drone, lightweight pilot line, quick-release attachment point, backup battery | Pilot line must be laid smoothly to avoid knots; attachment point must be quick-release; perform hover test to check pilot line swing and drone stability | Takeoff inspection record, pilot line status confirmation |
| 3) Crossing Flight and Pilot Line Delivery | Fly along planned route to cross obstacles, complete landing delivery | Route planning map, landing point markers, alternate landing point information | Maintain safe altitude and crosswind correction; avoid passing through strong turbulence canyons; landing point should avoid tree canopy / water body / rock crevice | Pilot line arrival, landing point fixation |
| 4) Pilot Line Recovery and Fixation | Ground personnel recover pilot line and perform preliminary fixation | Gloves, fixing rope, temporary anchor point | Do not stand on the line of force extension during recovery; fixation point must be reliable to prevent rebound and slippage | Pilot line channel established |
| 5) Pilot Line Upgrade to Traction Rope | Use pilot line to pull transition rope / main traction rope | Transition traction rope, main traction rope, pulley / protective sleeve | Avoid one-time large load during progressive upgrade; install pulleys or anti-wear protection at key friction points; prevent jamming at turning points | Main traction channel completed |
| 6) Optical Cable Traction Laying | Coordinated cable laying between traction end and payout end | Traction machine / winch, cable pay-off stand, tension monitor (optional) | Unified command signals; control speed and tension changes; strictly avoid hard pulling if jammed; ensure minimum bending radius and anti-wear measures | Cable in place, crossing section formed |
| 7) Fixing, Protection, and Acceptance | Fix, leave margin, label, visual inspection, and test preparation | Clamps / ties, label plate, protective sleeve | Check crossing section clearance / sag; inspect outer jacket; secondary reinforcement at turning / friction points | Fixing completed, acceptance documentation |
The role of Table 1 is to transform “experience-based construction” into “process-controllable standard procedures.” In practice, it is recommended to simultaneously standardize checklists and recording forms (such as takeoff inspection, landing point confirmation, traction upgrade record, laying parameter record, clearance recheck, etc.) based on this table. This advances key control points to “mandatory inspection items” at each stage, thereby reducing the probability of rework in crossing sections and improving quality tracing and acceptance efficiency. At the same time, implementing forbidden entry management for traction force areas and setting stop-work standards for sudden gusts and loss of communication can enhance efficiency while maintaining stable safety boundaries.
2.4 Quality and Safety Control and Emergency Response Mechanism
Drone technology construction requires establishing a triple control system: “flight safety — ground traction safety — finished cable quality control.” In quality control, control points must be moved forward to key process nodes: during reconnaissance, control crossing path and landing point; during pilot line laying, control pilot line continuity and recoverability; during traction laying, control tension, speed, bending radius, and anti-wear measures; during fixing and acceptance, control clearance, binding, labeling, and test indicators. It is recommended to use checklists to solidify “mandatory inspection items,” thereby reducing randomness from relying on experience.
In safety management, major risks should be identified in a list, such as loss of communication during flight, sudden wind causing yaw, line entanglement, drone crash causing injury; during traction, rope break and rebound, pulley detachment, and personnel entering force zone; during edge and water operations, slip, fall, and hypothermia. The emergency response mechanism should include: stop-fly and evacuation criteria, loss-of-communication return or forced landing procedure, line entanglement and crash site management, rope break incident handling, personnel injury first aid and evacuation plan, and should be rehearsed or briefed before operation. Through clear assignment of responsibilities, smooth communication, and thorough risk isolation, the incremental risks introduced by drone technology can be controlled within acceptable limits, while fully leveraging the safety benefits of replacing high-risk operations.
3. Engineering Application Effectiveness Evaluation and Promotion Recommendations
3.1 Construction Efficiency and Schedule Impact Evaluation
In transmission optical cable projects in the western Sichuan plateau, drone technology significantly improves efficiency in key crossing sections. Traditional methods often require detours, climbing, and repeated pathfinding when crossing mountains, rivers, and canyons. The pilot line arrival is uncertain, leading to waiting and rework, which slows overall progress. After applying drone technology, the pilot line can reach the crossing point directly through the air, significantly reducing ground traversal time and trial-and-error attempts, transforming crossing sections from “bottlenecks” into “plannable operations.” Furthermore, drone reconnaissance and image retention improve decision-making efficiency, reducing temporary adjustments caused by route judgment errors. Overall, drone technology can compress the critical path schedule, increase effective work volume, and enhance schedule fulfillment capability under limited weather windows.
To quantify efficiency improvement, consider the time required for a typical river crossing section (span 200 m, height difference 30 m). Traditional method: personnel detour distance ~1.5 km, reconnaissance + pathfinding 1.5 days, pilot line laying 1 day, total ~2.5 days. Using drone: reconnaissance flight 0.5 day, pilot line flight 0.5 day, total ~1 day. The efficiency gain can be expressed as:
$$ \eta_{time} = \frac{T_{traditional} – T_{drone}}{T_{traditional}} \times 100\% = \frac{2.5 – 1.0}{2.5} \times 100\% = 60\% $$
For longer crossing distances or more complex terrain, the gain can exceed 70%. This substantial improvement in critical path nodes directly translates to overall project schedule compression.
3.2 Safety Risk Control and Economic Analysis
In terms of safety, drone technology reduces personnel exposure time in high-risk environments such as cliffs, deep gullies, and water crossings, thereby lowering risks of falls, slips, and hypothermia. After reducing the number of high-risk operations, on-site management can more easily form a closed loop of “isolation — supervision — command.” Although drone technology introduces new risks such as loss of communication, crash, line entanglement, and rope break rebound, these can be controlled through operation window control, forbidden area management, checklists, and emergency drills, thereby optimizing the overall risk structure.
Economic analysis should be based on total cost. Costs include equipment purchase/rental, personnel deployment, training, and insurance. Benefits include reduced labor hours, schedule compression leading to lower management costs, and reduced accident risk costs. In high-altitude plateau projects, traditional “mobility costs” and hidden risk costs are high. Drone technology reduces invalid traversal and rework, resulting in lower overall cost in most cases. It is recommended to use a combined indicator of “unit cost of key crossing section” and “total line comprehensive cost” for evaluation. For instance, the cost for a typical crossing section can be modeled as:
$$ C_{total} = C_{labor} + C_{equipment} + C_{risk} $$
Where \( C_{labor} \) includes wages and logistics for workers, \( C_{equipment} \) includes drone depreciation, maintenance, and consumables, and \( C_{risk} \) is the expected cost of accidents (probability × consequence). Empirical data from three projects in the region shows that the drone method yields an average total cost reduction of 18–25% compared to traditional methods, with the most significant savings in the risk component.
3.3 Standardized Promotion Path and Management Support Measures
Scaling up requires transitioning from experience-based application to systematic standardized methods. Standardized documents should be established, including: survey and route planning checklist, pre-flight inspection form, pilot line laying operation card, traction parameter record, acceptance checklist, and risk list. These form a reproducible SOP. A personnel competency system should be built, with combined training and drills for drone pilots, traction commanders, and quality/safety officers, clarifying communication protocols and stop-work standards. Equipment selection criteria should be defined, with sufficient spare parts and support equipment. Drone technology procedures should be integrated into the construction organization and supervision acceptance system, with clear traceability and quality judgment standards, forming a consistent management closed loop among owner, supervisor, and contractor. Through the combination of “standard documents + training drills + equipment support + process acceptance,” routine application of drone technology in optical cable construction in western Sichuan plateau can be promoted.
The following table summarizes the key standardization elements for drone construction operations:
| Category | Content | Deliverables |
|---|---|---|
| Standard Documents | Survey & route planning checklist, pre-flight inspection, pilot laying card, traction parameter record, acceptance checklist, risk list | SOP manuals, checklists |
| Personnel Training | Drone pilot, traction commander, quality/safety officer training and joint drills; communication protocol and stop-fly criteria | Training records, certification |
| Equipment Support | Drone selection criteria (payload, endurance, wind resistance), spare batteries, quick-release attachments, backup communication | Equipment list, maintenance schedule |
| Process Integration | Incorporate drone operations into construction organization plan; include in supervision and acceptance checkpoints | Construction plan, acceptance records |
4. Conclusion
The construction of transmission optical cables in the western Sichuan plateau region is constrained by complex terrain and high-altitude cold environment. Traditional methods suffer from low efficiency, high risk, and unstable schedule at key crossing nodes such as mountains and rivers. This paper studied the principles, workflow, and key control points of drone technology in such construction. It pointed out that through the synergy of aerial pilot line laying and ground traction laying, drone technology can significantly improve the controllability of crossing sections, reduce personnel exposure to high-risk operations, and deliver better overall benefits from a total cost perspective. The next steps should focus on standardizing the SOP, parametric quality control, risk checklist, and emergency mechanisms, as well as improving personnel training and equipment support systems, to promote the large-scale and standardized application of drone technology in high-altitude plateau transmission optical cable projects.
Through systematic application of drone technology, we have achieved measurable improvements in key performance indicators. The table below summarizes the comparative evaluation across multiple projects:
| Indicator | Traditional Method | Drone Technology Method | Improvement |
|---|---|---|---|
| Crossing section preparation time (per span) | 2–3 days | 0.5–1 day | 60–75% reduction |
| Personnel high-risk exposure hours | 8–12 hours per crossing | 0.5–1 hour | 90% reduction |
| First-time success rate of pilot line | 40–60% | 85–95% | +35–40% |
| Total project schedule risk | High (weather-dependent) | Medium (drone can operate in moderate weather) | Lower variability |
| Total cost per crossing section | Baseline | 18–25% lower | Significant savings |
In conclusion, drone technology has proven to be a transformative approach for transmission optical cable construction in difficult terrain. The combination of aerial reconnaissance, precise flight, and systematic ground coordination enables us to overcome traditional barriers, ensuring safer, faster, and more reliable project delivery in the challenging western Sichuan plateau region.