WO2017072109A1

WO2017072109A1 - A sign monitoring apparatus, related methods and systems

Info

Publication number: WO2017072109A1
Application number: PCT/EP2016/075661
Authority: WO
Inventors: Manuel MAESTRINI; Roberts LAPINS
Original assignee: Nordsense Ivs
Priority date: 2015-10-27
Filing date: 2016-10-25
Publication date: 2017-05-04

Abstract

This disclosure provides a sign monitoring apparatus for mounting on a sign. The sign monitoring apparatus comprises a first sensor configured to measure a first parameter indicative of a position of the sign; and/or a second sensor configured to measure a second parameter indicative of a condition related to the sign. The sign monitoring apparatus comprises a processing unit operatively connected to the first and/or second sensor, the processing unit being configured to generate monitoring data indicative of a state of the sign based on the measured first and/or second parameter; an interface unit configured to communicate the monitoring data; and a memory unit configured to store the monitoring data.

Description

A SIGN MONITORING APPARATUS, RELATED METHODS AND SYSTEMS

FIELD OF THE INVENTION

The present disclosure pertains to the field of safety management, in particular to monitoring of signs, such as safety signs. The present disclosure relates to a sign monitoring apparatus, related methods and systems.

BACKGROUND OF THE INVENTION

Safety signs, such as road signs, are everywhere and play a vital role on safety management of common or public spaces, e.g. roads. Such signs provide instructions and warnings to users of the common or public space so as to preserve the safety of the users and provide accountability for a liable party, such as a property owner, a road construction manager.

However, safety signs are often vandalized, stolen or rendered invisible to users, such as motorists, due to external factors, such as strong wind. Due to these reasons maintenance personnel is required to periodically check, often multiple times a day, the state and orientation in space of safety signs.

The above practice is inefficient, very expensive, and not easily scalable. More specifically, the current practice is tedious and not timely. For example, when a safety sign happens to fall down shortly after a routine check was performed, such an event that renders the safety sign unseen and increases a safety risk would only be detected at the next routine check, often several hours later. This leaves a non-negligible time window where an accident may happen with potential liability despite the routine check.

Furthermore, to provide accountability, workers performing routine checks traditionally keep a log book of their routine check and possibly take a photographic, timestamped evidence of the sign and site checked. These measures provide some level of accountability but do not enable a fast reaction to remedy to a safety risk.

There is thus a need for alleviating the lack of efficiency, reliability and scalability of the existing monitoring techniques as well as a need for providing accountability for the presence and state of the signs. SUMMARY

It is an object of the present disclosure to provide sign monitoring apparatuses, systems, and methods that attempt to alleviate, and/or mitigate the problems or disadvantages in the prior-art. This object is obtained by a sign monitoring apparatus for mounting on a sign. The sign monitoring apparatus comprises a first sensor configured to measure a first parameter indicative of a position of the sign; and/or a second sensor configured to measure a second parameter indicative of a condition related to the sign. The sign monitoring apparatus comprises a processing unit operatively connected to the first and/or second sensor, the processing unit being configured to generate monitoring data indicative of a state of the sign based on the measured first and/or second parameter; an interface unit configured to communicate the monitoring data; and a memory unit configured to store the monitoring data.

The present disclosure advantageously provides remote monitoring of signs, of e.g. a safety sign, which increases the ability to react promptly if any deficiency of a sign occurs. The present disclosure also provides a scalable solution to the monitoring of signs as well as reliable accountability of the presence and/or state of the signs.

The present disclosure relates to a sign monitoring system, the sign monitoring system comprising a sign monitoring data collector apparatus. The sign monitoring data collector apparatus comprises a collector interface unit configured to receive monitoring data from a sign monitoring apparatus.

The sign monitoring data collector apparatus comprises a collector processing unit configured to determine a state indicative of the sign, based on the received monitoring data; and a collector data storage unit configured to store the state, and/or the received monitoring data. The state is an operating state indicative of the ability of the sign to fulfil appropriately its task of informing (e.g. informing pedestrians of a wet floor), for example an alarm/warning state, a non-operational state, and/or an operational state. According to some aspects, the collector interface unit is configured to receive a warning signal and the collector data storage unit is configured to store the warning signal. According to some aspects of this disclosure, the sign monitoring system comprises a sign monitoring apparatus as disclosed herein. The present disclosure relates to a method for monitoring a sign. The method comprises measuring a first parameter indicative of a position of the sign and/or a second parameter indicative of a condition related to the sign.

The method comprises generating monitoring data indicative of a state of the sign based on the measured first and/or second parameter. The state is for example an alarm/warning state, a non-operational state, and/or an operational state.

The method comprises communicating the generated monitoring data and storing the generated monitoring data.

The present disclosure relates to a method for fitting (such as retrofitting) a sign monitoring apparatus as disclosed herein onto a sign. The method comprises mounting the sign monitoring apparatus onto a sign, using e.g. detachably attached connectors.

This disclosure also relates to a computer program or a non-transitory computer- readable memory including a computer program, comprising computer readable code which, when run on a processing unit of a sign monitoring apparatus, causes the sign monitoring apparatus to perform any of the methods disclosed herein for monitoring a sign.

This disclosure also relates to a computer program or a non-transitory computer- readable memory including a computer program, comprising computer readable code which, when run on a collector processing unit of a sign monitoring data collector apparatus, causes the sign monitoring data collector apparatus to perform any of the methods steps disclosed herein for collecting sign monitoring data.

The computer programs, the systems, and the methods provide advantages corresponding to the advantages already described in relation to the apparatuses.

BRIEF DESCRIPTION OF THE FIGURES Embodiments of the invention will be described in more detail in the following with regard to the accompanying figures. The figures show one way of implementing the present invention and are not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

Figs, la-b are block diagrams illustrating exemplary sign monitoring apparatuses according to aspects of this disclosure. Fig. 2a is a schematic illustration of an exemplary sign monitoring apparatus mounted on a sign according to aspects of this disclosure.

Fig. 2b is a schematic illustration of an orientation of an exemplary sign monitoring apparatus according to aspects of this disclosure. Figs. 3a-b are schematic illustrations of a magnetic north sensed by an exemplary second sensor in various conditions according to aspects of this disclosure.

Fig. 4a is a schematic illustration of a sign monitoring system according to this disclosure.

Fig. 4b is a block diagram illustrating an exemplary sign monitoring data collector apparatus according to this disclosure.

Fig. 5 is a flow chart illustrating an exemplary method for monitoring a sign according to aspects of this disclosure.

Fig. 6 is a flow chart illustrating an exemplary method for collecting sign monitoring data according to aspects of this disclosure. DETAILED DESCRIPTION OF THE INVENTION

The present teaching relates to sign monitoring apparatuses, systems and methods for monitoring a sign. The present technique is applicable to any sign, such as a safety sign that is placed indoor and/or outdoor. The present technique is applicable to a sign monitoring system where there is a need for a reliable, and scalable monitoring of signs placed in a space where users of the space need to be informed of any hazards in that space.

As mentioned in the background section, such signs are vulnerable to various external factors that may take place in surroundings of such signs. Such external factors may lead to a sign being totally malfunctioning, i.e. not be able to achieve its informational purpose and prevent misguidance or accidents. As in the example of a road sign, a strong wind or a vehicle bumping into the road sign can render the sign unseen by road users (e.g. motorists, pedestrians) and may lead to accidents. For safety of the road users, such an event has to be detected and/or reported as soon as it takes place to minimize the time to remedy and the liability of entity managing the road. Today, signs are checked physically in person by having workers checking the signs one by one on site and reacting only when a malfunction or faulty condition is physically noted on site. Such practice is not easily scalable.

The present disclosure provides a sign monitoring apparatus that allows remote surveillance of a sign using one or more sensors, and remote reporting via an interface unit. The term "sensor" used herein refers to a unit or module capable of detecting/measuring a characteristic in its surrounding, such as a change or an event, and of providing an output corresponding to the detected characteristic. The sensor may be any sensor capable of detecting a characteristic such as a physical characteristic related to motion, light, temperature, vibration, sound, and/or magnetic field.

The present disclosure enables sensor measurements of one or more parameters indicative of a position and/or a condition related to the sign. Such spatial and/or environmental measurements permits according to this disclosure, to derive monitoring data that may further support generating a warning signal in case of detected malfunction. The raw measurement data provided by the one or more sensors is processed by the processing unit to generate the monitoring data, which is condensed or summarized representation of the state of the sign. This reduces power consumption at the sign monitoring apparatus as the inventors found that processing measurement data into monitoring data (i.e. condensed) consumes less power than transmitting measurement data (that is larger in size). The inventors have found that an interface unit (e.g. a cellular modem) consumes a lot more power than the processing unit. The present disclosure enables reliable and fast detection of a state or status of a sign (i.e. an operating state, e.g. functional or operational, malfunctioned, non-operational, wa rning/alarm). It is an advantage of the present disclosure that a fleet of signs can be monitored remotely and centrally, allowing a fleet manager to plan appropriate actions when necessary based on accurate and up-to-date monitoring data provided by the sign monitoring apparatuses.

Aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. The methods, apparatuses disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout. The terminology used herein is for the purpose of describing particular aspects of the disclosure only, and is not intended to limit the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The present disclosure relates to a sign monitoring apparatus for mounting on a sign. A sign as used herein refers to a static indicator that is placed in a space to provide information/instruction/guidance to a recipient, such as a user. Example of signs include a safety sign, a traffic sign, a road sign, a warning sign, a slab, a wall guiding users and a prohibitory sign. The sign monitoring apparatus disclosed herein assists in monitoring any of the signs exemplified herein.

The sign monitoring apparatus comprises a first sensor configured to measure a first parameter indicative of a position of the sign, such as a shifted position or an unchanged position. A position refers herein to a location and/or an orientation. A location relates to a placement or a point in a space with respect to a referential. Examples of location include geographic location on Earth, and/or location relative to another object or sign. An orientation comprises an indication of pitch, yaw and/or roll (stated differently tilt or inclination). The first sensor is for example configured to measure at least one first parameter indicative of a position, such as a first primary parameter, a first secondary parameter etc. The first sensor comprises for example a spatial sensor, such as a motion sensor capable of measuring a spatial parameter (e.g. a position parameter, an orientation parameter, a localization parameter). The first sensor may comprise one or more of first primary sensor, first secondary sensor, a first tertiary sensor, etc. In one or more examples, the first sensor may comprise a first primary sensor (e.g. an accelerometer), a first secondary sensor (e.g. a magnetometer) and/or a first tertiary sensor (e.g . a global positioning sensor).

Additionally, or alternatively, the sign monitoring apparatus comprises a second sensor configured to measure a second parameter indicative of a condition related to the sign. The term "condition" refers to the environment around the sign such as temperature, light, sound, pressure. A second sensor comprises for example an environmental sensor capable of measuring/detecting parameters such as light, pressure, sound and/or temperature.

The sign monitoring apparatus comprises a processing unit operatively connected to the first and/or second sensor. The processing unit is provided using any combination of one or more of a suitable central processing unit, CPU, multiprocessor, microcontroller, digital signal processor DSP, application specific integrated circuit, ASIC, field programmable gate arrays, FPGA, graphical processing unit, GPU etc., capable of executing software instructions or computer readable code stored in a computer program, e.g . in the form of a storage medium. Thus the processing unit is thereby arranged to execute methods for monitoring a sign as disclosed herein. The processing unit is configured to generate monitoring data indicative of a state of the sign based on the measured first and/or second parameter. A state of the sign refers to a state indicative of the ability of the sign to operate properly or to perform its function (e.g. indicating to a motorist a rule), an operating state, a state change, or a status, such as operational, non-operational (e.g. warning state, out-of-battery, disconnected, reset). The monitoring data generated includes for example position information (such as a location and/or an orientation) of the sign, and/or condition information (such as temperature). For example, the monitoring data comprises a series of first parameters and/or a series of second parameters, optionally including timestamps. For example, the monitoring data comprises a series of tuple comprising a first parameter, a second parameter, and optionally time of detection/measurement.

The sign monitoring apparatus comprises an interface unit configured to communicate the monitoring data; and a memory unit configured to store the monitoring data. The interface unit comprise for example a communication unit that is configured to transmit and/or receive data, mainly transmit monitoring data and possibly receiving/transmitting configuration data. An example of an interface unit includes a sound and/or light emitting unit. A preferred embodiment includes an interface unit that has a radio communication capability to communicate monitoring data. The memory unit is for example a data storage medium such as a collocated data storage medium, a remote data storage medium, removable and non-removable storage medium including, but not limited to, Read Only Memory, ROM and any related ROMs, Random Access Memory, RAM. The memory unit may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

In one or more exemplary sign monitoring apparatuses, the processing unit is configured to generate the monitoring data by comparing previous monitoring data and the monitoring data to obtain a difference result, and determining if the difference result is equal or larger than a warning threshold. For example, the processing unit is configured to compare any of previous monitoring data (e.g. any of the previous measured first and/or second parameters) and the monitoring data, (e.g. latest generated or current monitoring data) to obtain a difference result. When there is no previous monitoring data stored on the memory unit, the comparison is performed with respect to default values, or initial values configured at setup, or zeros, whichever appropriate. The warning threshold may be set at setup and may be adjustable for each situation, set in a device configuration phase, or dynamic and modifiable remotely. This provides the possibility to customize sensitivity of each apparatus.

In one or more exemplary sign monitoring apparatuses, in response to the difference result being equal or larger than a warning threshold, the processing unit is configured to generate the monitoring data by generating a warning signal. Optionally, the interface unit is configured to communicate the generated warning signal, to e.g. a sign monitoring data collector apparatus.

In one or more exemplary sign monitoring apparatuses, the processing unit is configured to generate the monitoring data by filtering noise from the measured first and/or second parameter. For example, the processing unit is configured to filter noise from the measured first and/or second parameter by applying noise filtering techniques (such as a low pass filter), averaging over the measured parameters, computing the median of the measured parameters, and/or determining the most frequently occurring value amongst the measured parameters. In one or more exemplary sign monitoring apparatuses, the processing unit is configured to generate the monitoring data by encoding the monitoring data into a format acceptable to a receiver. The receiver comprises for example a sign monitoring data collector apparatus in the vicinity of the sign and/or remotely located, such as across a network. According to some aspects, the sign monitoring apparatus comprises an energy storage unit, such as a battery. The energy storage unit may be a conventional battery. The energy storage unit may comprise one or more primary or secondary batteries, to store and deliver power to on-board units of the sign monitoring apparatus. The energy storage unit may be connected to an energy source/converter such as an ambient energy harvesting source. Optionally, the energy storage unit may be used in conjunction with ambient energy harvesting sources such as: photovoltaic, piezo electric, magnetic induction, etc. to extend battery life and achieve self-sustainability. The energy source is selected so that it is long lasting, e.g. several months to years, as a way to minimize the frequency of battery replacement routines. Optionally, the energy source also has a connection terminal or a cable assembly attached or embedded by using for example molex connectors or any other connectors which can greatly reduce the effort needed to replace the battery. In one or more exemplary sign monitoring apparatuses, the sign monitoring apparatus comprises a power management unit configured to control power supply to units of the sign monitoring apparatus.

In one or more exemplary sign monitoring apparatuses, the interface unit comprises a wireless communication unit configured to transmit the monitoring data and/or the generated warning signal. Examples of wireless communications unit comprise a cellular modem (such as a 2G, 3G, 4G, 5G modem), which, if applying power saving techniques according to this disclosure, provides advantages in terms of range, and reduced complexity compared to short-range technique. Short-range techniques such as Bluetooth require a master-slave network topology and thus some complexity in setting up such network topology, as well some weaknesses as the master node (or sink) becomes a single point of failure. A wireless ad-hoc or self-organized network of sign monitoring apparatuses may be envisaged where a plurality of sign monitoring apparatuses collaborate to communicate with a sign monitoring data collector apparatus. Such a network may optionally include a gateway or a router configured to communicate with a sign monitoring data collector apparatus or one or more sign monitoring apparatuses configured to act as a gateway or router to the sign monitoring data collector apparatus. It is thus an advantage of the present disclosure that when the interface unit is a wireless cellular communication unit, there is no need for master- slave network topology and thus no single point of failure. However, as cellular wireless communications are known to consume much more power than short-range, the present disclosure proposes a power efficient sign monitoring apparatus. The sign monitoring apparatus disclosed herein may be configured to set the interface unit in low-power modes (e.g. sleep mode, light sleep mode, coma sleep mode, hibernate mode) when not in use, i.e. between periodic reports. Furthermore, the sign monitoring apparatus disclosed herein may optionally comprise a power management unit configured to control or to lower power supply to units of the sign monitoring apparatus, such as the interface unit (e.g. even power down the unit) when there is no transmission and/or reception ongoing/upcoming. The power management unit may control connection to the processing unit, the one or more sensors, and/or the interface unit. Examples of power management units include a voltage regulating unit, a low drop out, LDO, power management unit, an external transistor such as a metal-oxide- semiconductor field-effect transistor, MOSFET, a relay such as a solid state relay, solid state switch, and/or a thyristor. Such embodiment provides a power saving of up to 1000 folds. For example, a GSM modem consumes around 380mA while sending; about 18mA in idle mode; 0.8 to 1mA in sleep mode; and 50uA in power down mode. To put it in a perspective, a regular rechargeable 18650 Lithium Ion battery of capacity 2000mAh could power a modem for 4 days in idle mode, a little over 2 months in sleep mode, and in power-down mode over 20% of the battery capacity would be used up by device performing no communication operations. For this reason, instead of relying on internal power management mechanism of the individual unit, the inventors found it beneficial to instead use an external power management unit operatively connected to the processing unit and the interface unit, and/or the one or more sensors. By using for example a MOSFET on a power line to the interface unit, it is possible to disconnect the interface unit from the energy storage unit, such that connection is initiated only when specifically required, i.e. upon transmission or reception. In such approach the current consumption may be reduced typically to l-3uA. Over a period of 1 year, this results in total of 9mAh consumed, or just about 0.4% of the mentioned battery capacity. This presents a significant improvement over unit integrated or internal power management schemes. This is applicable to each unit comprised the sign monitoring apparatus (e.g. sensors, memory).

In one or more exemplary sign monitoring apparatuses, the first sensor comprises one or more of a sensor configured to measure a position and/or an orientation; a sensor configured to identify a location and/or a path; an accelerometer; a gyroscope; a transducer; a magnetometer; an inclinometer. Optionally, the first sensor comprises a sensor configured to measure and/or detect spatial change, such as a movement, vibration. In one or more exemplary sign monitoring apparatuses, the first sensor comprises one or more of a sensor configured to detect a position and/or an orientation, such as a changed position and/or changed orientation, a sensor configured to detect a changed location and/or changed inclination. The first parameter comprises for example a position parameter such as a location parameter (e.g . a longitude parameter, a latitude parameter), a region parameter, a vicinity parameter, an orientation parameter and a range parameter. The orientation parameter comprises for example a pitch parameter, a yaw parameter, and/or a roll parameter. To obtain a location parameter, the cheapest option may be to simply use GSM triangulation at no extra cost. However, the lack of precision in such approach (accuracy is generally 150-300 meters in urban areas and up 2-5 kilometres in rural area) is not optimal for the disclosed sign monitoring apparatus. Another approach is to use a global positioning sensor, but that also has limitation in precision (less than 3.5m). The inventors found that the optimal approach is to use hybrid satellite configuration, where instead of a single satellite constellation, multiple satellite constellations are used, which may include constellations from a Global Navigation Satellite System, GNSS, e.g. : American GPS, European Galileo, Russian Glonass, Chinese Beidu and Japanese QZSS. To achieve further efficiency, a first primary sensor acting as a location sensor may be configured to only check for GNSS location readings (e.g. longitude, latitude) when one or more of a first secondary sensor and tertiary sensor acting as orientation sensors (e.g. magnetometer and accelerometer) have detected significant change in orientation.

When not in low-power mode, wireless communication units tend to be highly power consuming. For example, a GSM unit especially tends to consume from 50mA in startup, to 300mA in full-operation. For example, a rechargeable 18650 2000mAh lithium ion battery is able to handle around 200 to 400 GSM transmissions, depending on distance from the tower, before the battery is fully depleted. Thus, according to this disclosure, units of the sign monitoring apparatus are powered on upon operation. For example, a first sensor such as a location sensor (e.g. a GPS unit) is according to this disclosure to be turned on when a significant change has been detected in the pitch, tilt or yaw (i.e. a change beyond a threshold). For example, an interface unit such as a GSM unit is powered on upon transmission, and/or periodically for reception/transmission. According to this disclosure, the sign monitoring apparatus is configured to apply throttling, i.e. the interface unit is turned on at a pre-defined event, such as at least after a pre-determined period (e.g. 30 to 60 minutes) has elapsed since the last successful transmission. This ensures that while the sign with the sign monitoring apparatus mounted on is in constant motion (for example due to transport), the sensed constant position change is not transmitted and thus the power consumption still remains limited. Furthermore, if the sign monitoring apparatus experiences an unsuccessful transmission, the sign monitoring apparatus may be configured to stay in idle mode for a time period (e.g. 15 minutes) before retransmission.

In one or more exemplary sign monitoring apparatuses, the second sensor comprises one or more of a sensor configured to measure light parameters; a sensor configured to measure temperature; a sensor configured to measure pressure. In one or more exemplary sign monitoring apparatuses, the processing unit is configured to generate the monitoring data by compensating distortions affecting the first sensor and/or the second sensor due to a ferrous surrounding. Alternatively or additionally, the first sensor and/or the second sensor may be configured to measure the first/second parameter by compensating distortions created by a ferrous surrounding. The ferrous surroundings or neighbouring areas are likely to happen when the sign is made of a ferrous material such as iron or steel. Magnetic distortion takes place due to the sign monitoring device being mounted on a ferrous sign, or placed in a ferrous environment. When the first sensor and/or the second sensor is a magnetometer, such distortions result in erroneous readings from the magnetometer. The disclosed sign monitoring apparatus solves this by compensating such distortions. In one or more exemplary sign monitoring apparatuses, the processing unit and/or the first sensor and/or the second sensor is configured to compensate distortions by calibration of the first sensor and/or the second sensor, such as by calibrating based on input from the first sensor and/or the second sensor. While a sensor configured to detect an orientation parameter (such as a magnetic parameter) is factory calibrated, the calibration is often imprecise and can differ from batch to batch. Furthermore, in real life scenarios, when the sensor configured to detect a magnetic parameter is in presence of ferrous material (the problems becomes apparent even when the ferrous material is around 1 meter away), the measurements become even more distorted, limiting the applicability only to aluminium or plastic based signs. To alleviate this, the disclosed sign monitoring apparatus, the processing unit is configured to calibrate the first and/or second sensor using soft iron and/or hard iron techniques to compensate for these distortions. In one or more exemplary sign monitoring apparatuses, the first sensor configured to measure an orientation (such as a magnetometer) is advantageously placed near a part of sign monitoring apparatuses so that when the sign monitoring apparatus is mounted on the sign, the first sensor is located outside the post comprised in the sign. This may advantageously provide a faster and more efficient compensation for distortion. The present disclosure relates to a sign monitoring system, the sign monitoring system comprising a sign monitoring data collector apparatus. The sign monitoring data collector apparatus comprises a collector interface unit configured to receive monitoring data from a sign monitoring apparatus (such as in a cloud architecture, remotely located from the sign monitoring apparatus). According to some aspects, the collector interface unit may be configured to send configuration data e.g. to the sign monitoring apparatus, and to receive requests from the sign monitoring apparatus and/or a client device (possibly operated by a user) for upgrade, for configuration instruction on device level, for report generation, and/or for history overview. The collector interface unit may be configured to receive input from other units, processes or other entities in the sign monitoring system. The collector interface unit may comprise a user interface configured to output monitoring data, or state indicative of the sign to a user. The user interface may be configured to receive user input.

The sign monitoring system may comprise a client device adapted to request monitoring data from the sign monitoring data collector apparatus. The sign monitoring data collector apparatus comprises a collector processing unit configured to determine a state indicative of the sign (such as an operating state), based on the received monitoring data; and a collector data storage unit configured to store the state, and/or the received monitoring data. According to some aspects, the collector interface unit is configured to receive a warning signal and the collector data storage unit is configured to store the warning signal.

According to some aspects of this disclosure, the sign monitoring system comprises a sign monitoring apparatus as disclosed herein.

The present disclosure relates to a method for monitoring a sign. The method comprises measuring a first parameter indicative of a position of the sign and/or a second parameter indicative of a condition related to the sign.

The method comprises generating monitoring data indicative of a state of the sign based on the measured first and/or second parameter.

The method comprises communicating the generated monitoring data and storing the generated monitoring data. The present disclosure relates to a method for fitting (such as retrofitting) a sign monitoring apparatus as disclosed herein onto a sign. The method comprises mounting the sign monitoring apparatus onto a sign, using e.g. detachably attached connectors.

The present disclosure relates to a sign comprising a sign monitoring apparatus according to this disclosure. The present disclosure relates to a method for collecting sign monitoring data. The method comprises:

- receiving monitoring data (e.g. from a sign monitoring apparatus);

- determining a state indicative of the sign based on the received monitoring data; and - storing the state, and/or the received monitoring data, such as in a collector storage unit.

The method for collecting sign monitoring data may further comprise sending configuration data to a sign monitoring apparatus.

Fig. la shows a block diagram schematically illustrating an exemplary sign monitoring apparatus 100 according to aspects of this disclosure. The sign monitoring apparatus 100 comprises a first sensor 101 configured to measure a first parameter indicative of a position of the sign, such as a shifted position or an unchanged position. Additionally, or alternatively, the sign monitoring apparatus 100 comprises a second sensor 102 configured to measure a second parameter indicative of a condition related to the sign. The sign monitoring apparatus 100 comprises a processing unit 103 operatively connected to the first sensor 101 and/or the second sensor 102. The processing unit 103 is configured to generate monitoring data indicative of a state of the sign based on the measured first and/or second parameter. Hence the processing unit 103 comprises for example a generator unit 103a configured to generate monitoring data indicative of a state of the sign based on the measured first and/or second parameter. Optionally, the processing unit 103 is configured to generate the monitoring data by comparing previous monitoring data and the monitoring data to obtain a difference result, and by determining if the difference result is equal or larger than a warning threshold. Hence the processing unit 103 comprises for example a comparer unit 103b configured to compare previous monitoring data and the monitoring data to obtain a difference result and a determiner unit 103c configured to determine if the difference result is equal or larger than a warning threshold. The warning threshold is for example set at setup and is adjustable for each situation, set in a device configuration phase, or dynamic and modifiable remotely. This provides the possibility to customize sensitivity of each apparatus. In one or more exemplary sign monitoring apparatuses, in response to the difference result being equal or larger than a warning threshold, the processing unit 103 is configured to generate the monitoring data by generating a warning signal. Hence, the generator 103a is configured to generate a warning signal. Optionally, the interface unit 104 is configured to communicate the generated warning signal, to e.g. a sign monitoring data collector apparatus.

The sign monitoring apparatus 100 comprises an interface unit 104 configured to communicate the monitoring data; and a memory unit 105 configured to store the monitoring data. The interface unit comprise for example a communication unit that is configured to transmit and/or receive data, mainly transmit monitoring data and possibly receiving/transmitting configuration data. The interface unit 105 has a radio communication capability to communicate monitoring data. The interface unit 105 comprises for example a wireless communication unit configured to transmit the monitoring data and/or a warning signal. Examples of wireless communications unit comprise a cellular modem (such as a 2G, 3G, 4G, 5G modem), possibly configured to enter low power modes.

In one or more exemplary sign monitoring apparatuses, the processing unit 103 is configured to generate the monitoring data by filtering noise from the measured first and/or second parameter. Hence the processing unit 103 comprises for example a filter unit 103d configured to filter noise from the measured parameters. For example, the processing unit 103 or filter module 103d is configured to filter noise from the measured first and/or second parameter by applying noise filtering techniques (such as a low pass filter), averaging over the measured parameters, computing the median of the measured parameters, and/or determining the most frequently occurring value amongst the measured parameters.

In one or more exemplary sign monitoring apparatuses, the processing unit 103 is configured to generate the monitoring data by encoding the monitoring data into a format acceptable to a receiver. Hence the processing unit 103 comprises for example an encoder unit 103e configured to encode the monitoring data into a format acceptable to a receiver. The processing unit 103 or the encoder unit 103e encodes the monitoring data into a format understandable by a receiver, delivering such monitoring data using for example: tcp/udp sockets and / or http requests.

According to some aspects, the sign monitoring apparatus 100 comprises an energy storage unit 106, such as a battery. The energy storage unit 106 may be a conventional battery. The energy storage unit 106 may be connected to an energy source/converter such as a solar panel. Furthermore, the sign monitoring apparatus 100 may optionally comprise a power management unit 107 configured to lower power supply to one or more of the units comprised in the sign monitoring apparatus 100, such as the interface unit 104 (e.g. even cut-off power supply) when there is no transmission and/or reception ongoing/upcoming. The power management unit 107 may be connected and control the power supply to the processing unit 103, the one or more sensors 101, 102, and the interface unit 104.

Fig. lb shows a block diagram illustrating an exemplary sign monitoring apparatus 110 according to aspects of this disclosure. In this illustrative example where the disclosed technique is applicable, the sign monitoring apparatus 110 comprises a processing unit 101 as described above, a first primary sensor 101a, a first secondary sensor 101b, an interface unit 104, a memory unit 105, and an energy storage unit 106. In this example, the first primary sensor 101a is a spatial sensor configure to measure an orientation, such as a magnetometer, while the first secondary sensor 101b is an accelerometer. Measurements of orientation in space may alternatively be performed using gyroscope. However, the inventors found that a gyroscope consumes significant power, as it requires the processing unit 103 to be powered at all time, since it can only provide relative values representing change of orientation in space if the gyroscope is being constantly sampled. This would drastically reduce battery life down to few days or weeks, which is too far from a target battery life of months to years. Furthermore, any interruption of power to the processing unit 103 or restart would compromise the reliability of information since the relative change provided by the gyroscope has no baseline to be compared with (i.e. no previous measurements). For these reasons, a combination of accelerometer and magnetometer is preferred. This combination can be turned on and off at will, since the accelerometer and magnetometer provide absolute values as opposed to relative ones, without requiring the accelerometer and magnetometer to be on at all times.

The processing unit 103 is configured to generate monitoring data and optionally to determine a warning situation by comparing a current orientation and location to the previous stored orientation and location (so called baseline), to determine whether a warning threshold condition is met. When such condition is met, i.e. the warning threshold is reached or exceeded, the processing unit generates a warning signal and initiates communication via the interface unit 104 to report the warning signal and/or monitoring data to a remote server.

The processing unit 103 may be configured to periodically run self-assessing cycles, according to its configuration settings. Every assessment cycle, the processing unit 103 compares its current location and orientation in space to the baseline values stored on the memory unit 105, which are the first or latest values recorded after the sign has been correctly positioned. If the change in location or orientation in space is larger than the allowed warning threshold set or predetermined by the configuration settings, the processing unit 103 enters an alarm state in which the processing unit 1 requests powering on the interface unit 104 and requests the interface unit 104 to reports the monitoring data (i.e. current location and orientation in space to the remote server), and/or the alarm state. The processing unit 103 may be configured to increase the frequency of communication/reporting of monitoring data and/or warning signal, until the monitoring data and/or warning signal is acknowledged by the receiver. Optionally, a warning signal may be sent in form of remote system notifications such as sms, email, phone call, push notification etc.

Fig. 2a is a schematic illustration of an exemplary sign monitoring apparatus 100, 110 mounted on a sign 200 according to aspects of this disclosure. The sign 200 comprises a post. In one or more embodiments, the sign monitoring apparatus 100, 110 is mounted on the post of the sign 200 as illustrated in Fig. 2a by the arrow. Thus, a part of the sign monitoring apparatus 100 is placed within the post and a part of the sign monitoring apparatus 100, 110 is placed outside the post. The present disclosure relates to a sign 200 comprising a sign monitoring apparatus according to this disclosure. Fig. 2b is a schematic illustration of an orientation of an exemplary sign monitoring apparatus 100, 110 according to aspects of this disclosure. As the sign monitoring apparatus 110, 110 is to be mounted on a sign, an orientation of the sign can be measured or monitored by measuring or monitoring an orientation of the sign monitoring apparatus 100, 110. Fig. 2b illustrates the orientation of the exemplary sign monitoring apparatus 100, 110 with respect to three axes that enable the measurement of a yaw parameter, a pitch parameter, and/or a roll parameter. The first sensor is configured to measure/detect a first parameter indicative of a position of the sign, such as an orientation illustrated in Fig. 2b in terms of yaw parameter, pitch parameter, and/or roll parameter. The first sensor comprises for example a first primary sensor and/or a first secondary sensor, acting possibly jointly as an orientation sensor, such as a multi-axis accelerometer and a multi-axis magnetometer.

In an illustrative example of this disclosure, the first (primary) sensor is an accelerometer measuring strength and direction of acceleration in 3 dimensions (XYZ) and it is expressed in m/s². From the accelerometer, due to earth's gravity being a known value of approximately 9,81 m/s², the processing unit is capable of calculating an upward facing vector of the accelerometer, for example x axis representing value of -9.81 m/s². Knowing the up vector and heading, the processing unit is capable of calculating the pitch parameter, roll parameter and yaw parameter. The combination of these parameters allows to derive the orientation in space of the accelerometer, of the sign monitoring apparatus, and therefore of the sign. Pitch parameter and roll parameter represent a side and front tilt, whereas the yaw parameter represents a sign direction towards the magnetic north.

Figs. 3a-b show schematic diagrams illustrating measurements of a magnetic north sensed by an exemplary second sensor in various conditions according to aspects of this disclosure. Fig. 3a shows schematically a circle which is an ideal distribution of the magnetic north during a full rotation (from 0 to 360 deg rees (in case of a single axis, such as XY)) of the sign monitoring apparatus performed in calibration. The circle is the ideal target result from a calibration. This may be done by rotating the apparatus or the first sensor full-circle around each of the axes to gather enough data for drawing a 3D sphere. Ideally the sphere will be uniform in shape and perfectly centred, however it is rarely the case in reality. Figs. 3a-b. show a coordinate plane in each figure, which represents a two dimensional plane of calibration for illustrative purposes. The actual calibration occurs in 3D dimensions and in reality the calibration plane is a 3D plane. However, for the sake of simplicity, 2D operations are carried out in this example. When the sign monitoring apparatus 100, 110 is rotated around its centre point, the first sensor configured to measure position follows the same rotation, such that the points of the "front" of the first sensor in multiple directions produces a set of points. Fig. 3a shows the set of points in an XY plane, and which forms in ideal conditions, a uniform circle illustrated herein. When normalized, the uniform circle is in exact centre of the XY plane.

According to this disclosure, when provided with an ideal distribution of the magnetic north represented by an ideal representation (i.e. the circle of Fig.3a) in an XY plane, the apparatus 100, 110 may be configured to obtain initial parameters indicative of the current distribution of the magnetic north detected by the first sensor in presence of ferrous material. The current distribution of the magnetic north detected by the first sensor may be represented in a XY plane in a first representation. The apparatus 100, 110 may be configured to identify a transformation that transforms the first representation into the ideal representation, and to generate a plurality of calibration/compensation parameters indicative of the identified transformation. Fig. 3b shows schematically a result of a hard iron distortion on the first sensor (e.g. a magnetometer). In a hard iron distortion situation, the centre point of set of points is offset from the centre of the XY plane. In this example, the transformation from the offset circle to the centred circle is thus a translation parameterized by a vector indicative of it.

Fig. 3c shows schematically shows a result of soft iron distortion on the first sensor (e.g . a magnetometer). In a soft iron distortion situation, the set of point forms a skewed, and rotated ellipsoid. After calibration of the first sensor, the set of points measured by the calibrated first sensor shall form / be close to forming an almost ideal uniform circle. In this example, the transformation from the skewed, and rotated ellipsoid to the centred circle is thus a rotation and deformation parametrized by a matrix as given below.

In an illustrative example of this disclosure, the first (secondary) sensor is a magnetometer measuring a strength of Earth's magnetic field in 3 dimensions (XYZ) provided in e.g. micro teslas (uT) and used to calculate the direction towards the magnetic north. Through the application of inverse trigonometric mathematics, it is possible to calculate the heading of the magnetometer in degrees (0-360 or -180 to + 180) or radians. Due to presence of ferrous material, such as iron or steel, in the magnetometer vicinity, then the measurements are distorted and the processing unit or the first sensor compensates for these distortions, by establishing the current set of points when rotating the first sensor a full circle in 2 or 3 axis. When a soft- iron distortion is present (see Fig. 3c), the circle may look skewed or rotated. It is possible to account for this by applying an ellipsoid fit calculation to a raw data set. In the calibration process, calculations may be performed using a transformation matrix that transforms the ellipsoid back to a sphere or the ellipse back to a circle.

In case of hard iron distortion, the offset from centre (0,0,0) needs to be compensated for. This may be done by calculating the minimum and maximum values for each of the axis, such that: Bx = (xmin + xmax) / 2; By = (ymin +ymax) / 2; By = (ymin +ymax) /2. These offsets are then subtracted from the raw magnetometer measurements representing the first or second parameter measured . To apply the results, calculations may be performed using a hard iron transformation matrix and subtract bias in order to get calibrated measurement results, e.g. in the following way: Xcal Mi l M12 M13 X raw^' Bx

Ycal = M21 M22 M23 Yraw - By

^X

.Zeal. M31 M32 M33. V .Zraw . Bz. where vector [Xcal, Ycal, Zeal] denotes a vector indicative of calibrated measurement results (i.e. results from calibration of a vector representing the first parameter, or the second parameter); matrix [M 11...M33] represents the soft-iron ellipsoid-fit transformation matrix; vector [Xraw, Yraw, Zraw] denotes a vector indicative of raw uncalibrated values (i.e. a vector representing a measured first parameter, or second parameter) and vector [Βχ,Βν,Βζ] represents hard-iron offset or bias in each direction.

Fig. 4a shows a schematic illustration of a sign monitoring system 400 according to this disclosure. The sign monitoring system 400 comprises a sign monitoring data collector apparatus 410. According to some aspects of this disclosure, the sign monitoring system 400 comprises a sign monitoring apparatus 100, 110 as disclosed herein.

The sign monitoring data collector apparatus 600 comprises a collector interface unit 604 configured to receive monitoring data from a sign monitoring apparatus, e.g. from a sign monitoring apparatus 100, 110, possibly via a communication network 450. The collector interface unit 601 may be configured to send configuration data to the sign monitoring apparatus 100, 110. The collector interface unit 601 may be configured to receive input from other units, processes or other entities in the sign monitoring system. The collector interface unit 601 may comprise a user interface configured to output monitoring data, or state indicative of the sign to a user. The user interface may be configured to receive user input.

The sign monitoring data collector apparatus 600 comprises a collector processing unit 603 configured to determine a state indicative of the sign based on the received monitoring data; and a collector data storage unit 602 configured to store the state, and/or the received monitoring data. The collector data storage unit 602 is for example a data storage medium such as a collocated data storage medium, a remote data storage medium, removable and non-removable storage medium including, but not limited to, Read Only Memory, ROM, Random Access Memory, RAM. The memory module 601 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory. The collector processing unit 603 is provided using any combination of one or more of a suitable central processing unit, CPU, multiprocessor, microcontroller, digital signal processor DSP, application specific integrated circuit, ASIC, field programmable gate arrays, FPGA, graphical processing unit, GPU etc., capable of executing software instructions or computer readable code stored in a computer program, e.g. in the form of a storage medium. Thus the collector processing unit 603 is thereby arranged to execute methods for collecting sign monitoring data as disclosed herein. The state is for example an alarm/warning state, a non-operational state, and/or an operational state. According to some aspects, the collector interface unit 601 is configured to receive a warning signal from e.g. the sign monitoring apparatus 100, 110 and the collector data storage unit 602 is configured to store the warning signal. Fig. 4b shows a block diagram illustrating an exemplary sign monitoring data collector apparatus 600 according to this disclosure. The sign monitoring data collector apparatus 600 comprises a collector interface unit 604 configured to receive monitoring data from a sign monitoring apparatus, e.g . from a sign monitoring apparatus 100, 110, possibly via a communication network 450. The collector interface unit 601 may be configured to send configuration data to the sign monitoring apparatus 100, 110. The sign monitoring data collector apparatus 600 comprises a collector processing unit 603 configured to determine a state indicative of the sign based on the received monitoring data; and a collector data storage unit 602 configured to store the state, and/or the received monitoring data. The state is for example an operating state indicative of the ability of the sign to operate properly, such as an alarm/warning state, a non- operational state, and/or an operational state. According to some aspects, the collector interface unit 601 is configured to receive a warning signal from e.g . the sign monitoring apparatus 100, 110 and the collector data storage unit 602 is configured to store the warning signal. Fig. 5 shows a flow chart illustrating an exemplary method 500 for monitoring a sign according to aspects of this disclosure. The method 500 for monitoring a sign may be performed in a sign monitoring apparatus disclosed herein. The method 500 comprises measuring SI a first parameter indicative of a position of the sign and/or a second parameter indicative of a condition related to the sign. Optionally, measuring SI may further comprise compensating distortions created by a ferrous surroundings, by e.g . calibration.

The method comprises generating S2 monitoring data indicative of a state of the sign based on the measured first and/or second parameter. Generating S2 comprises for example comparing previous monitoring data and the monitoring data to obtain a difference result, and determining if the difference result is equal or larger than a warning threshold. Optionally, generating S2 may further comprise generating a warning signal in response to the difference result being equal or larger than a warning threshold. In one or more exemplary methods 500, generating S2 may further comprise filtering noise from the measured first and/or second parameter. In one or more exemplary methods 500, generating S2 may further comprise encoding the monitoring data into a format acceptable to a receiver. Optionally, generating S2 may further comprise compensating distortions affecting the first/second sensor due to a ferrous surrounding, by e.g. calibration. The method comprises communicating S3 the generated monitoring data and storing S4 the generated monitoring data.

The present disclosure relates to a method for fitting (such as retrofitting) a sign monitoring apparatus as disclosed herein onto a sign. The method comprises mounting the sign monitoring apparatus onto a sign, using e.g. detachably attached connectors. Fig. 6 shows a flow chart illustrating an exemplary method 550 for collecting sign monitoring data according to aspects of this disclosure. The method 550 for collecting sign monitoring data may be performed in a collector system, or a sign monitoring data collector apparatus. The method 550 comprises receiving Sxl monitoring data (e.g. from a sign monitoring apparatus). The method 550 comprises determining Sx2 a state indicative of the sign based on the received monitoring data; and storing Sx3 the state, and/or the received monitoring data e.g. in a collector storage unit.

The method for collecting sign monitoring data may further comprise sending Sx4 configuration data to a sign monitoring apparatus.

The various exemplary embodiments described herein are described in the general context of method steps or processes, which may be implemented in one aspect by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), compact discs (CDs), digital versatile discs (DVD), etc. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes. It shall be appreciated that Figs. 1-6 comprises some modules or operations which are illustrated with a darker border and some modules or operations which are illustrated with a dashed border. The modules or operations which are comprised in a darker border are modules or operations which are comprised in the broadest example embodiment. The modules or operations which are comprised in a dashed border are example embodiments which may be comprised in, or a part of, or are further modules or further operations which may be taken in addition to the modules or operations of the darker border example embodiments. It should be appreciated that operations need not be performed in order. Furthermore, it should be appreciated that not all of the operations need to be performed. The example operations may be performed in any order and in any combination.

It should be appreciated that the example operations of Figs. 5 and 6 may be performed simultaneously for any number of components and apparatuses.

Aspects of the disclosure are described with reference to the drawings, e.g., block diagrams and/or flowcharts. It is understood that several entities in the drawings, e.g., blocks of the block diagrams, and also combinations of entities in the drawings, can be implemented by computer program instructions, which instructions can be stored in a computer-readable memory, and also loaded onto a computer or other programmable data processing apparatus. Such computer program instructions can be provided to a processor of a general purpose computer, a special purpose computer and/or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer and/or other programmable data processing apparatus, create means for implementing the functions/acts specified in the block diagrams and/or flowchart block or blocks.

In some implementations and according to some aspects of the disclosure, the functions or steps noted in the blocks can occur out of the order noted in the operational illustrations. For example, two blocks shown in succession can in fact be executed substantially concurrently or the blocks can sometimes be executed in the reverse order, depending upon the functionality/acts involved. Also, the functions or steps noted in the blocks can according to some aspects of the disclosure be executed continuously in a loop.

In the drawings and specification, there have been disclosed exemplary aspects of the disclosure. However, many variations and modifications can be made to these aspects without substantially departing from the principles of the present disclosure. Thus, the disclosure should be regarded as illustrative rather than restrictive, and not as being limited to the particular aspects discussed above. Accordingly, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. In the drawings and specification, there have been disclosed exemplary embodiments. However, many variations and modifications can be made to these embodiments. Accordingly, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the embodiments being defined by the following claims.

Claims

1. A sign monitoring apparatus for mounting on a sign, the sign monitoring apparatus comprising : a first sensor configured to measure a first parameter indicative of a position of the sign; and/or a second sensor configured to measure a second parameter indicative of a condition related to the sign; a processing unit operatively connected to the first and/or second sensor, the processing unit being configured to generate monitoring data indicative of an operating state of the sign based on the measured first and/or second parameter; an interface unit configured to communicate the monitoring data ; and a memory unit configured to store the monitoring data ; wherein the processing unit is configured to generate the monitoring data by filtering noise from the measured first and/or second parameter.

2. The sign monitoring apparatus according to claim 1, wherein the processing unit is configured to generate the monitoring data by: comparing previous monitoring data and the monitoring data to obtain a difference result, determining if the difference result is equal or larger than a warning threshold.

3. The sign monitoring apparatus according to claim 2, wherein in response to the difference result being equal or larger than a warning threshold, the processing unit is configured to generate the monitoring data by generating a warning signal.

4. The sign monitoring apparatus according to any of the previous claims, the sign monitoring apparatus comprising a power management unit configured to control power supply to units of the sign monitoring apparatus.

5. The sign monitoring apparatus according to any of the previous claims, wherein the processing unit is configured to generate the monitoring data by encoding the monitoring data into a format acceptable to a receiver.

6. The sign monitoring apparatus according to any of the previous claims, wherein the interface unit comprises a wireless communication unit configured to transmit the monitoring data and/or the generated warning signal.

7. The sign monitoring apparatus according to any of the previous claims, wherein the first sensor comprises one or more of a sensor configured to measure a position and/or an orientation; a sensor configured to identify a location and/or a path; an accelerometer; a gyroscope; a transducer; a magnetometer; an inclinometer; and/or wherein the second sensor comprises one or more of a sensor configured to measure light parameters; a sensor configured to measure temperature; a sensor configured to measure pressure.

8. The sign monitoring apparatus according to any of the previous claims, wherein the processing unit is configured to generate the monitoring data by compensating distortions affecting the first sensor and/or the second sensor due to a ferrous surrounding.

9. The sign monitoring apparatus according to claim 8, wherein the processing unit is configured to compensate distortions by calibration of the first sensor and/or the second sensor.

10. A sign monitoring system, the sign monitoring system comprising a sign monitoring data collector apparatus, the sign monitoring data collector apparatus comprising : - a collector interface unit configured to receive monitoring data from a sign monitoring apparatus;

- a collector processing unit configured to determine an operating state indicative of the sign, based on the received monitoring data; and

- a collector data storage unit configured to store the operating state, and/or the received monitoring data.

11. The sign monitoring system according to claim 10, the sign monitoring system comprising a sign monitoring apparatus according to any of claims 1-9.

12. A method for monitoring a sign, the method comprising : measuring a first parameter indicative of a position of the sign and/or a second parameter indicative of a condition related to the sign; generating monitoring data indicative of an operating state of the sign based on the measured first parameter and/or the measured second parameter, - communicating the monitoring data; and storing the monitoring data.

13. A sign comprising a sign monitoring apparatus according to any of claims 1-9.

14. A non-transitory computer readable storage medium comprising a computer program comprising computer readable code which, when run on a processing unit of a sign monitoring apparatus, causes the sign monitoring apparatus to perform method claimed in claim 12.

15. A non-transitory computer readable storage medium comprising a computer program comprising computer readable code which, when run on a processing unit of a sign monitoring data collector apparatus, causes the sign monitoring data collector apparatus to perform a method comprising :

- receiving monitoring data;

- determining an operating state indicative of the sign based on the received monitoring data; and

- storing the operating state, and/or the received monitoring data.