Low-Cost Safety and Fleet Telemetry Module for Rental Watercraft

Defensive Prior Art Disclosure

Low-Cost Safety and Fleet Telemetry Module for Rental Watercraft

Statement of Intent

This document is published as a defensive prior art disclosure. The author makes the system and methods described below publicly available to form prior art against later attempts to patent the disclosed combinations.

No exclusive patent rights are asserted by the author over the concepts expressly disclosed here.

Technical Field

The disclosure concerns low-cost monitoring of fleets of small watercraft, including:

• rental kayaks;
• canoes;
• pedal boats;
• small rowing boats;
• stand-up paddle boards;
• small recreational motorboats;
• other watercraft for which a full marine computer would be economically or energetically impractical.

Background and Technical Problem

A rental operator needs to know whether a craft has left an authorized area, stopped unexpectedly, capsized, been transported away or failed to return. A conventional marine chartplotter is too expensive and consumes too much energy to install on every kayak or pedal boat.

Ordinary vehicle trackers also have shortcomings. They may assume frequent charging, permanent cellular coverage and motion characteristics typical of land vehicles. Watercraft are exposed to rocking, splashing, slow drift, weak network coverage and long periods without access to power.

Summary of the Disclosed Solution

The disclosed solution is a sealed telemetry module containing at least:

• a processor;
• a GNSS receiver;
• an inertial measurement unit;
• a wireless communication device;
• non-volatile storage;
• a battery or vessel-power interface.

The module periodically determines position and motion state, creates compact telemetry or alarm records and transmits them to a fleet-management service. It can continue recording when wide-area communication is unavailable and transmit stored records later.

Hardware Arrangement

The module may be enclosed in a tamper-resistant, waterproof housing attached to or incorporated into the watercraft.

The inertial measurement unit may contain a three-axis accelerometer and optionally a gyroscope. A magnetometer, water-contact sensor, pressure sensor, temperature sensor, battery monitor or enclosure-open sensor may also be provided.

The communication device may comprise one or more of:

• a cellular modem;
• a sub-gigahertz radio;
• a LoRa or LoRaWAN transceiver;
• Bluetooth;
• Wi-Fi;
• a short-range proprietary radio.

Operational States

An exemplary state machine includes:

1. Storage state — the craft is stored and position is sampled infrequently.
2. Available state — the craft is at the rental base and ready for assignment.
3. Trip state — movement consistent with an active rental is detected or a rental is opened by the fleet system.
4. Stationary-on-trip state — the craft has stopped during a rental.
5. Alarm state — an abnormal position, orientation or communication condition is detected.
6. Return state — the craft re-enters the base zone and remains there for a defined period.

State changes may be triggered by fleet-server commands, GNSS position, IMU activity, a physical button, NFC interaction, QR-code rental activation or proximity to a base radio.

Position and Geofence Monitoring

The fleet-management system stores one or more geographic regions, such as:

• the rental base;
• an allowed water area;
• a planned river corridor;
• a prohibited zone;
• a recovery or service area.

The module or server evaluates the craft position relative to these regions. An event may be generated when the craft enters, leaves or remains outside a region for longer than a configured time.

A river corridor may be represented by a sequence of route points with a permitted lateral distance rather than by a simple circle.

Basic Capsize or Abnormal Orientation Detection

An orientation event can be detected using fixed, configurable rules. For example, a possible capsize is identified when:

• roll or pitch exceeds a threshold angle;
• the threshold persists for a minimum time;
• the orientation is accompanied by a characteristic acceleration event, water-contact indication or loss of forward movement.

To avoid reporting every wave as a capsize, the event may be cancelled if normal orientation returns within a short confirmation interval.

The rules and thresholds may differ by craft type. A kayak, pedal boat and small motorboat may use different configuration profiles.

Unexpected Stop and Overdue Return

The system may identify an unexpected stop when the craft remains within a small area for longer than a configured duration during an active trip.

This event is not necessarily an emergency. It may be assigned a severity depending on:

• distance from accessible shore;
• time remaining before darkness;
• elapsed rental time;
• water or weather conditions obtained by the server;
• simultaneous abnormal-orientation or water-contact data.

An overdue event may be produced when the craft has not returned by the expected time, regardless of whether the module is currently reachable.

Store-and-Forward Communication

Every telemetry record may contain:

• device and craft identifier;
• sequence number;
• acquisition time;
• position and position quality;
• motion or orientation summary;
• battery level;
• operational state;
• event flags.

Records are stored locally before or during transmission. If an acknowledgement is not received, the records remain queued. After connectivity returns, records are delivered in sequence or in compressed batches.

Alarm records may be sent before routine historical records.

Base Station and Fleet Manager

A rental base may operate a local sub-gigahertz gateway connected to the fleet server. This allows telemetry to be received in locations with weak cellular coverage.

The fleet manager presents:

• last known location;
• position age;
• active or inactive rental state;
• craft battery level;
• alarms and their acknowledgement state;
• historical route;
• maintenance notes;
• a list or map of all craft.

The system may group craft by owner, rental base, type, season or service status.

Example Alarm Escalation

1. A possible capsize rule is satisfied.
2. The module records a high-rate sample window around the event.
3. A local audible or visible indication gives the user an opportunity to cancel a false alarm.
4. If not cancelled, a compact alarm packet is transmitted.
5. The server marks the craft on the fleet map and notifies an operator.
6. Later telemetry updates may confirm recovery, continued abnormal orientation or movement toward shore.

Energy-Conservation Measures

The GNSS receiver and modem may remain powered down between scheduled observations. The IMU may use a low-power motion interrupt to wake the processor.

Sampling may be less frequent while the craft is stored and more frequent during an active rental or alarm. Records may be batched to reduce radio start-up overhead.

These measures may be implemented with fixed schedules and predefined state-dependent intervals.

Variants

The module may:

• be assigned permanently to one craft or temporarily attached;
• communicate directly with a cloud server or through a base gateway;
• use a customer's phone as an optional forwarding device;
• operate without any customer-facing application;
• expose a simple customer page showing rental time and return direction;
• include a manual assistance button;
• detect removal from the craft using an enclosure sensor or attachment loop.

Technical Effects and Advantages

The disclosed solution provides:

• fleet visibility without installing a full onboard computer;
• operation on battery-powered small craft;
• continued data collection outside cellular coverage;
• earlier detection of capsize, overdue return and unauthorized removal;
• one common fleet system for different types of watercraft;
• low-cost deployment across many rental units.

Technical Concepts Disclosed for Prior Art Purposes

This publication expressly discloses:

1. a low-cost GNSS and IMU telemetry module specifically used across a rental-watercraft fleet;
2. storage, trip, stationary, alarm and return operating states;
3. corridor geofencing for river rentals;
4. fixed-rule capsize detection combining orientation duration with motion or water-contact information;
5. store-and-forward telemetry through cellular or sub-gigahertz links;
6. prioritization of alarm packets over routine history;
7. a rental-base radio gateway serving multiple watercraft;
8. state-dependent GNSS and radio sampling intended to conserve energy.

Public Availability Declaration

The expressly disclosed concepts are made available for public implementation and extension. This publication is intended to prevent later claims that these broad combinations were previously undisclosed.