Relative Positioning in Motion · AGV Fleet Management · Deadlock Resolution

Sensor Fusion and Innovative Relative Positioning

An AGV's LiDAR SLAM answers "where am I" but not "is anyone nearby". P-Square fills that gap with an innovative relative positioning mechanism: a UWB PDOA multi-antenna anchor mounted on the vehicle measures range and bearing to nearby tagged workers and material carts while the vehicle is moving, complementing the on-board LiDAR SLAM and encoder fusion positioning. A fleet management system supports AGVs and AMRs from different manufacturers and resolves fleet deadlock in narrow areas.

Architecture: Relative Positioning in Motion

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Figure: sensor fusion positioning — a vehicle-mounted UWB PDOA anchor performs relative positioning of nearby personnel tags while in motion.

Conventional RTLS mounts anchors on walls and tags on people. P-Square adds another option: mount the UWB PDOA multi-antenna anchor on the AGV or AMR itself. For safety applications, what a vehicle actually needs is not its absolute coordinate on the site map but the bearing and distance to the nearest person.

Three sensing modes complement one another:

LiDAR SLAM + encoder — localises the vehicle by matching environmental contours, but cannot identify moving objects.
UWB PDOA relative positioning — measures bearing and range directly to tagged personnel, unaffected by lighting or line-of-sight blind spots.
RGBD imaging — compensates for LiDAR's limited field of view and assists obstacle avoidance.

The decisive difference is knowing before you can see. LiDAR and cameras both have to see something before they can react, and the moment a person steps out from behind a rack, a corner or a large machine, the vehicle often has less than a second to stop. UWB signals penetrate and diffract, so the vehicle already has that person’s bearing and range before they come into view — enough warning for the AGV to slow down, reroute or stop rather than brake hard on sight. Backlight, dust and darkness make no difference either.

Fixed anchors can be added to obtain absolute coordinates and relative range simultaneously.

How the Two Systems Divide the Work

System	Problem solved	Core mechanism
Sensor fusion AGV / AMR positioning	Safety in mixed human-vehicle traffic: blind spots at corners and between racking, workers straying into travel lanes.	Vehicle-mounted UWB PDOA relative positioning with LiDAR SLAM and encoder fusion; traffic and zone control able to trigger slow-down or stop.
AGV / AMR fleet management	Dispatch efficiency across many vehicles: which is where, which is idle, which are queued on the same route.	UWB positioning of the whole fleet with task status; supports AGVs and AMRs from different manufacturers; resolves deadlock in narrow areas.

System Capabilities

Item	Description
Relative positioning	Vehicle-mounted UWB PDOA array antenna resolves range and bearing from a single unit, maintained while in motion
Vehicle self-localisation	LiDAR SLAM fused with encoder data
Vision assistance	RGBD combined with LiDAR for navigation and obstacle avoidance
Multi-vendor support	Fleet management supports AGVs and AMRs from different manufacturers
Deadlock handling	Resolves mutual blocking of AGV fleets in narrow areas
Back-end functions	Restricted zones, historical records, heat maps, trajectory replay, dwell time
Integration	Web API and iframe integration with existing MES / WMS or dispatch systems

Where It Is Used

Production and warehousing: mixed human-vehicle safety, right-of-way arbitration at junctions
AGV fleet dispatch: position and task status dashboard, heat maps of congested route segments
Occupational safety: restricted-zone alerts for automated cells, able to trigger slow-down or stop
Asset management: automatic stocktakes of carts, fixtures and metrology instruments

Frequently Asked Questions

Our AGVs already run LiDAR SLAM — why add UWB?

SLAM answers where the vehicle is by matching environmental contours, but it cannot identify moving objects or tell whether a contour is a person or a pallet. UWB relative positioning fills exactly that gap: for tagged personnel the vehicle measures bearing and distance directly, unaffected by lighting or blind spots. The two are complementary, not alternatives.

Must every worker wear a tag? What about people without one?

UWB relative positioning only detects tagged personnel, so we recommend retaining the vehicle's existing LiDAR and vision-based obstacle avoidance as a second layer: LiDAR detects all obstacles while UWB precisely identifies the bearing and distance of people for earlier reaction. P-Square also offers an RGBD plus LiDAR navigation and obstacle-avoidance solution.

What is deadlock and how do you resolve it?

Deadlock occurs when several AGVs block one another in a narrow aisle or crossing area so that none can proceed and operations stall. The fleet management system uses UWB positioning to track the actual position and task status of the whole fleet, arbitrating right of way at junctions and narrow segments so that vehicles do not enter conflicting sections simultaneously.

Can you support our existing AGVs from different manufacturers?

Yes. The fleet management system is designed to support AGVs and AMRs from different manufacturers, and provides Web API and iframe integration with existing MES, WMS or dispatch systems.

Will factory metalwork affect UWB relative positioning?

UWB achieves 10–30 cm accuracy in line-of-sight conditions. Multipath effects in metallic environments are compensated with NLOS estimation together with particle filters and a motion model. Where centimetre-level precision is not required, a lower-cost Bluetooth solution is also available.

Let AGVs See People, and People See AGVs

Contact the P-Square project team to plan mixed-traffic safety and fleet dispatch.

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