What Goods-to-Person Systems Actually Do

In a traditional warehouse or fulfillment operation, workers spend anywhere from 50 to 70 percent of their shift walking. They push carts down long aisles, scan shelves, pull items, and walk back to packing stations. Multiply that across dozens of employees over multiple shifts, and the inefficiency adds up fast.

Goods-to-person (GTP) systems flip that model. Instead of sending workers to the inventory, the inventory comes to the worker. An automated system retrieves the required bin, tote, or pallet and delivers it to a fixed pick station where an operator selects the needed items. The operator stays in one spot, and the system handles all the travel.

This is not a new concept, but advances in robotics, sensor technology, and warehouse management software have made GTP systems far more accessible and versatile than they were even five years ago. What used to require massive capital outlay and years of planning can now be deployed in modular phases, scaling with demand.

Core GTP Technologies

There are several distinct approaches to goods-to-person fulfillment, and the right choice depends on your product mix, throughput targets, and facility constraints.

Automated Storage and Retrieval Systems (AS/RS)

AS/RS is the most established GTP technology. These systems use cranes, shuttles, or vertical lift modules (VLMs) to store and retrieve items from dense racking structures. Mini-load AS/RS systems handle totes and cartons, while unit-load systems move full pallets.

The main advantage of AS/RS is storage density. By eliminating conventional aisles and stacking vertically, these systems can store three to four times more inventory in the same floor space. That density comes with a trade-off: AS/RS installations are typically fixed infrastructure that requires significant upfront engineering and construction work.

Autonomous Mobile Robots (AMRs)

AMRs represent a more flexible approach. These robots navigate warehouse floors using onboard sensors and mapping software, carrying shelving units or totes to pick stations. Amazon's acquisition of Kiva Systems in 2012 brought this concept into the mainstream, and multiple vendors now offer AMR-based GTP solutions.

AMRs excel in facilities where layout flexibility matters. Unlike AS/RS, you can add robots incrementally and reconfigure zones without structural changes. The flip side is that AMRs require clear floor space to operate, and throughput per square foot typically lags behind dense AS/RS configurations.

Shuttle Systems

Shuttle-based systems use small vehicles that travel along rails within a racking structure. Each shuttle handles a specific level or zone, retrieving totes and delivering them to lifts that move product vertically to the pick station level. These systems offer a middle ground between the density of AS/RS and the modularity of AMRs.

Shuttle systems are particularly well-suited for operations with high SKU counts and moderate to high throughput requirements. They scale well because you can add shuttles to increase throughput without redesigning the racking layout.

Vertical Lift Modules and Carousels

For smaller operations or those with limited floor space, VLMs and horizontal or vertical carousels offer a compact GTP solution. These systems store items in trays or bins that rotate to an access window when requested. They work well for parts storage, kitting operations, and low to moderate volume picking.

Engineering Considerations for GTP Implementation

Throughput Modeling

Before selecting any GTP technology, you need a clear picture of your throughput requirements. This goes beyond simply counting orders per day. You need to understand peak versus average demand, order profiles (single-line versus multi-line), item characteristics (size, weight, fragility), and growth projections.

A common mistake is sizing a system to handle average throughput while underestimating peak demand. In fulfillment, the peaks are what matter. A system that handles daily averages but chokes during holiday surges or promotional events will create bottlenecks exactly when you can least afford them.

Integration with Existing Systems

GTP systems do not operate in isolation. They need to integrate with your warehouse management system (WMS), order management system (OMS), and often with upstream material handling equipment like conveyors, sortation systems, and packing lines. The integration layer is frequently where projects run into trouble.

Data exchange between the GTP system and your WMS must be reliable and fast. The GTP controller needs real-time inventory location data, order priority information, and replenishment triggers. If the WMS and GTP system are not tightly synchronized, you end up with operators standing idle while the system searches for inventory it cannot locate.

Facility Requirements

GTP systems impose specific demands on your facility. AS/RS installations need floors that meet strict flatness tolerances, often FF50 or better. The floor must also support concentrated point loads from racking and crane systems. AMR-based systems require smooth, level floors free of debris and obstructions.

Electrical infrastructure matters too. Dense GTP installations with hundreds of motors, sensors, and controllers draw significant power. You will also need robust network infrastructure, as modern GTP systems generate enormous volumes of data and depend on low-latency communication between components.

Ergonomics at the Pick Station

The pick station is where human performance and system performance intersect. A poorly designed pick station can negate much of the efficiency gained by automating travel. Key design factors include presentation angle, reach distance, lighting, display placement, and put-wall configuration.

The best pick station designs keep all required movements within a comfortable reach envelope, present items at an ergonomic height, and provide clear visual cues for pick location and quantity. Some systems use pick-to-light or augmented reality overlays to guide operators, reducing error rates to well below one percent.

Measuring GTP Performance

Pick Rate Improvements

Traditional person-to-goods picking typically yields 60 to 100 picks per hour per operator, depending on the operation. Well-designed GTP systems routinely achieve 200 to 400 picks per hour, with some high-performance installations exceeding 600. The improvement comes from eliminating travel time and optimizing the sequence in which items are presented.

Accuracy

Manual picking operations typically see error rates of one to three percent. GTP systems, particularly those with barcode or RFID verification at the pick station, can push error rates below 0.1 percent. In industries with strict accuracy requirements, such as pharmaceutical or medical device fulfillment, this improvement alone can justify the investment.

Space Utilization

Dense GTP systems can reduce the floor space required for a given inventory by 40 to 60 percent compared to conventional shelving. For operations in high-cost real estate markets, the savings in facility costs can significantly offset system costs.

Common Integration Points

GTP systems typically connect with several types of equipment and infrastructure. Conveyor systems feed inbound product to the storage system and move outbound orders from pick stations to packing and shipping. Sortation equipment downstream of the pick stations routes completed orders to the correct shipping lanes.

At the pick station itself, you may integrate scales for weight verification, vision systems for item identification, and automated labeling or documentation printers. Each of these integration points requires careful engineering to avoid introducing bottlenecks or failure points.

ROI and Payback Considerations

The economics of GTP systems depend heavily on your specific operation. Key variables include current labor costs, available labor supply, facility costs, order volume, and growth trajectory.

Labor savings are typically the largest ROI driver. A GTP system that triples pick rates effectively reduces the labor needed for a given throughput by two-thirds. In tight labor markets where finding and retaining warehouse workers is a constant challenge, this benefit extends beyond simple cost reduction.

Payback periods for GTP installations typically range from two to five years, depending on system complexity and the labor cost environment. Modular approaches like AMR-based systems tend to have shorter payback periods because you can start with a smaller investment and scale as volume grows.

Getting Started with GTP

If you are evaluating goods-to-person technology for your operation, start with a thorough analysis of your current state. Document your order profiles, pick rates, error rates, labor costs, and growth projections. This baseline data is essential for building a credible business case and for properly sizing any system you evaluate.

Visit reference sites if possible. Seeing a GTP system in operation gives you a much better sense of what is involved than any specification sheet or simulation. Talk to the operators at those sites, not just the managers.

Whether your operation needs a full-scale AS/RS installation, a fleet of AMRs, or a targeted deployment of VLMs for specific product categories, the key is matching the technology to your actual requirements rather than chasing the latest trend.

Partner With AMD Machines

AMD Machines designs and builds custom assembly and material handling systems for manufacturers across a range of industries. Our engineers work through the full project lifecycle, from concept and simulation through installation and commissioning, ensuring that every system meets real-world production demands. Contact us to discuss your fulfillment automation needs.