Application of ZigBee Semi-Active System Localization Technology in Outdoor Steel Inventory and Rapid Retrieval

I. Project Background and Core Objectives

The outdoor storage area of the steel mill is characterized by numerous steel batches, wide stacking ranges, and harsh environmental conditions (high temperature, rain, vibration). The existing system can only manage basic steel information and cannot associate physical locations, requiring manual area-by-area searches during retrieval. The average search time severely impacts production continuity efficiency and customer pickup speed.

The ZigBee Semi-Active System positioning technology aims for "precise positioning, rapid retrieval, and integration with the source system". Through the collaboration of tags and base stations, it achieves real-time location awareness for each batch of steel outdoors, while enabling data interoperability with the source system. This builds an integrated management system for "information - location", reducing the single retrieval time to within 2 minutes.

II. Technical Selection Basis: Why Choose ZigBee Semi-Active System Positioning Technology

Addressing the requirements of the steel mill's outdoor scenario, ZigBee Semi-Active System positioning technology offers significant advantages compared to other positioning technologies, with specific comparisons as follows:

III. Overall System Architecture Design

(I) Perception Layer: Core Hardware Deployment (Matching Requirement List)

ZigBee Semi-Active Light-emitting Tags (Bound to Steel)

• Core Parameters: Semi-active communication mode, supports ZigBee protocol + low frequency 125K; Protection rating IP67 (rainproof, dustproof); High-temperature resistance -20℃~70℃ (adapts to summer exposure and winter low temperatures in steel mills); Shock resistance rating IK08 (withstands steel stacking vibrations); Built-in unique ID (one-to-one binding with steel batch number); Equipped with LED light-emitting function (lights up during close-range retrieval for quick target steel identification); Battery life 2-5 years (low-power design, reduces replacement frequency).
• Installation Methods: Uses strong magnetic adsorption, screw fixation, zip tie binding, double-sided adhesive pasting (adsorbed on the side of steel bundles to prevent脱落 during hoisting).

ZigBee Semi-Active Card Reader Base Stations (Covering Storage Area)

• Core Parameters: Supports ZigBee semi-active tag reading (distance 10-100 meters, adjustable power to adapt to different stacking densities); Built-in 4G full-network module (supports long connection to external network servers for real-time data transmission and remote control); Protection rating IP67 (outdoor rainproof, corrosion resistant); Supports DC 12-24V dual power supply or solar + lithium battery (adapts to outdoor wiring scenarios); Possesses low-frequency 125K activation function (close-range assisted positioning); Built-in signal enhancement antenna (optimizes signal penetration in metal environments).
• Deployment Principles: Installed corresponding to steel stacking areas, deploying 1 base station per storage area to ensure no signal blind spots; Installation height above 2 meters (avoids steel hoisting paths while ensuring coverage), preferably fixed on storage area columns or fences.

(II) Transmission Layer: Data Transmission Channel Construction

• Core Transmission Link: Base stations establish long connections with external network servers via the 4G module, using TCP/IP protocol for encrypted transmission (prevents data leakage), uploading tag location data every 30 seconds (frequency adjustable on demand, balancing real-time performance and traffic cost).
• Edge Computing Optimization: Base stations have built-in simple data processing units, capable of filtering invalid data (e.g., tag signal jitter) before uploading valid data, reducing server computational load.

(III) Platform Layer: Data Hub and Source System Collaboration

Core Functional Modules

• Data Reception and Parsing: Receives tag ID, signal strength, timestamp, and other data uploaded by base stations in real-time, associates parsed data with steel batch information.
• Location Calculation Engine: Based on "point-to-point beacon positioning", calculates the specific coordinates of the steel (e.g., "Storage Area A - Row 3 - Pile 5").
• Source System Data Interface: Develops standardized API interfaces for bidirectional data synchronization with the existing source system — retrieves steel batch number, specifications, storage time, etc., from the source system, and pushes real-time steel location data to the source system, ensuring complete matching of "source system information - location".
• Database Design: Uses MySQL database, stores 3 types of core data: ① Steel basic information table (batch number, specifications, source system code); ② Tag association table (Tag ID – Steel batch number binding relationship); ③ Location record table (Steel real-time location, historical location轨迹).

(IV) Application Layer: Retrieval Function Implementation (For Different User Roles)

Web Management Platform (Suitable for Office Administrators)

• Real-time Location Monitoring: Displays steel distribution across all storage areas in map form; clicking a steel batch shows detailed information (location, specifications, storage time); supports filtering and positioning by "batch number, specifications, source system code".
• Retrieval Task Initiation: After synchronizing pickup demands from the source system, retrieval tasks can be directly initiated; the system automatically generates "target location".
• (3) Data Statistics Reports: Automatically generates reports such as "Retrieval Time Statistics", "Steel Turnover Rate", "Base Station Online Rate", supports Excel export, assists management decision-making.

PDA Mobile Terminal (Suitable for On-site Operators)

• Quick Goods Search: Quickly locates and finds target goods based on the map position located by the system.
• Quick Binding and Unbinding of Semi-Active Tags

IV. Project Benefit Analysis

Efficiency Improvement: Single retrieval time reduced from 1 hour to within 5 minutes, daily retrieval time reduced by 4-6 hours, pickup efficiency improved by over 10 times.

Cost Savings: Reduces manpower input for manual retrieval; calculated based on 2 rotating warehousekeepers, annual labor cost savings approx. 150,000 RMB; also avoids customer penalty fees due to retrieval delays, reducing hidden losses.

Management Optimization: Through location data追溯, steel turnover rate can be analyzed, optimizing storage layout (e.g., placing high-frequency pickup steel near the gate area); source system and location data collaboration eliminates "information - location" silos, inventory accuracy increased from 85% to 99.5%.

Risk Reduction: Tags feature waterproof, shockproof, high-temperature resistant characteristics, outdoor failure rate ≤0.5%; 4G long connection + data backup mechanism ensures no risk of data loss for the system.

V. After-Sales Service and Support

Hardware Warranty: Tags and base stations come with a 1-year warranty, free repair or replacement for non-human damage during the warranty period.

Software Maintenance: Provides 1 year of free maintenance after system launch, annual maintenance agreements available thereafter.

Emergency Response: Establishes a 7×24 hour technical support team for rapid response.