2361144 1 0:\SPECS\JG\P615.1wp Monitoring Apparatus and Method The present
invention relates to the monitoring of radio frequency electromagnetic radiation, and in particular to the monitoring of mobile telephone communications equipment.
The recent increase in the ownership and use of cellular mobile phones has lead to an equal increase in the infrastructure needed to service such phones. Typically mobile phone systems operate on a cellular network where a given area is divided into a plurality of cells each with its own radio transmitter and with which the phones can communicate when activated. All the cells are linked to an automatic base station that controls the switching requirements of the network. There presently exist two systems which are referred to as PCN (Personal Communications Network) and GSM (Groupe Speciale Mobile). PCN operates a frequency of around 1800 MHz and GSM at around 900 MHz.
To ensure adequate coverage within a cell it is often required to site additional communications equipment therein, such as relay stations, which can communicate with one another and the radio transmitter. Depending on it's position within a cell, this additional communications equipment may be sited on purpose built masts or alternatively installed on existing structures such as the roofs of tall buildings or church spires.
It is not uncommon for the installation of the additional communications equipment to be objected to on the ground that the equipment emits levels of electromagnetic radiation which may be hazardous to health. Objections raised against proposals to site new equipment often leads to installation delays.
According to a first aspect of the present invention there is provided apparatus for 330 monitoring radio frequency electromagnetic radiation comprising monitoring means adapted to monitor radio frequency electromagnetic radiation emanating from a source 2 and communication means operable to relay information from said monitoring means to a location remote from said electromagnetic radiation source.
The communication means may be adapted to relay said information continuously, at predetermined time intervals, or in response to predetermined criteria being met. For example the communication means may be activated should the monitoring means determine that the electromagnetic radiation has reached or exceeded a predetermined intensity.
In an alternative embodiment the apparatus may be adapted to monitor electromagnetic radiation emanating from a plurality of sources. The monitoring means may be directional and adapted to monitor electromagnetic radiation from a predetermined direction or directions.
In an alternative embodiment the monitoring means may be prompted to monitor the electromagnetic radiation emanating from the source and relay information from said monitoring means via the communication means in response to an input being received by the communication means.
The apparatus may include a self-contained power source. Such a power source may comprise power storage means, such as a battery, and one or more solar cells adapted to charge the battery. In an alternative embodiment the apparatus may be powered by a connection to a mains supply system.
The communication means may be a.wireless communication means, for example a mobile phone. In such an embodiment shielding means may be provided between the monitoring means and the communication means. Such shielding means may be required.in order that electromagnetic radiation emanating from the communication means is not registered by the monitoring means to give a false reading. The shielding 30 means may comprise a physical barrier and/or a predetermined spacing between the monitoring means and communication means. Alternatively, the apparatus may be configured so as to store in a memory information from the monitoring means, temporarily take the monitoring means off-line, and when said monitoring means is off-line operate the communication means. In an alternative embodiment the communication means may be connected to a land based telephone system.
In a preferred embodiment the apparatus is provided within a protective casing. The apparatus preferably includes security means to prevent unauthorised access thereto. The security means may include sensors adapted to sense movement of the apparatus. In such an embodiment, the sensors may generate an alarm signal when unauthorised movement of the apparatus is sensed and relay the alarm signal to the remote location.
According to a second aspect of the present invention there is provided a method of monitoring radio frequency electromagnetic radiation emanating from a source, the method comprising the steps of.
providing apparatus having monitoring means adapted to monitor radio frequency 15 electromagnetic radiation and communication means operable to relay information from said monitoring means to a location remote from said source; positioning said apparatus relative to said source; and relaying said information to said remote location.
In one embodiment the step of relaying said information to said remote location may be carried out should the monitoring means determine that the electromagnetic radiation emanating from the source has reached or exceeded a predetermined intensity. In an alternative embodiment the step of relaying said information to said remote location may be conducted continuously or alternatively at predetermined time intervals. In yet a flirther embodiment, the step of relaying said information to said remote location may be carried out in response to instructions sent to the apparatus from said remote location.
An embodiment of the present invention will now be described with reference to the 30 accompanying drawings in which:
Figure 1 shows a schematic representation of a monitoring apparatus according to the present invention; and 4 Figure 2 shows a schematic representation of a monitoring system according to the present invention.
Referring to the accompanying figures there is shown a monitoring apparatus generally designated 10. The apparatus 10 comprises a casing 12 containing a monitor 14 adapted to monitor radio frequency electromagnetic radiation, a power supply 16, and a wireless communications device 18. The power supply 16 is coupled to an array of solar cells 20 on the exterior of the casing 12. The casing 12 further contains motion sensors 22 which are adapted to sense unauthorised movement of the apparatus 10.
The monitor 14 is operable to detect both electric E-field radiation (measured in V/m) and magnetic H-field radiation (measured in A/m). Suitable monitors are commercially available, for example those manufactured by Wandel & Goltermann and more specifically the ESM-20, EMR20 and EMR-30 models.
In use, the apparatus 10 is sited at a predetermined location relative to a source 28 of radio frequency electromagnetic radiation, for example a communications mast 24 having an antenna 26 thereon. The casing 12 may be provided with brackets or the like to enable the apparatus 10 to be fixed in position with appropriate fastening means. In the present example, where it is desired to monitor the radiation from a single source, it is important that the site for the apparatus 10 is chosen carefully so as to minimise the possibility that it may be subjected to electromagnetic radiation emanating from other sources. Once in position the monitor 14 is operated so as to monitor the intensity of electromagnetic radiation emanating from the source 28.
In a first operative mode the apparatus 10 is operative as an alarm system so as to provide an alarm signal when the intensity of electromagnetic radiation emanating from the source 28 is equal to or exceeds a predetermined value. Once the monitor 14 detects the radiation intensity to have reached or exceeded the predetermined value, the wireless communication device 18 is operated to send a message, indicated by arrow 32, to a receiving station 30. The message 32 contains sufficient information to identify the particular apparatus 10 and source 28. Additionally the message 32 may also indicate the radiation intensity monitored by the monitor 14. The receiving station 30 may then pass this information, indicated by arrow 38, to an interested party 34, for example the company or organisation responsible for the operation and maintenance of the antenna 26.
In Europe there exist two recognised Authorities, the National Radiological Protection Board (NRPB) and the International Radiation Protection Authority (IRPA), which currently publish guidelines on the safe exposure levels to electromagnetic radiation. The monitor 14 may be set so as to provide an alarm signal when the radiation intensity from the source 28 exceeds, for example, 12.5%, 25%, 50% or 100% of the relevant NRPB or IRPA safe level for a given situation. The intensity required to trigger the alarm signal can be set when the apparatus 10 is installed.
The receiving station 30 may also place information, indicated by arrow 40, relating to the fact that the apparatus 10 has generated an alarm signal on a database 36. The database 36 may be accessible via the Internet. A party wishing to know whether or not the radiation emanating form a particular source 28 has exceeded a given intensity may access the database, identify the location of t he particular source 28 which is of interest to them and see whether apparatus 10 in the vicinity of the source 28 has generated an alarm signal.
In a second operative mode the apparatus 10 may operate to provide round the clock monitoring of the source 28. Depending upon system requirements, the wireless communications device 18 may relay information relating to the radiation intensity emanating from the source 28 either continuously or at predetermined time intervals. As before this information may be passed to an interested party 34 and/or placed in a publicly accessible database 36. The apparatus 10 may be switched between operative modes by a signal, indicated by arrow 42, sent from the receiving station 3 0.
Switching between operative modes may be initiated by an interested party 34. The interested party 34 may for the purposes of research or testing require continuous information relating to the electromagnetic radiation intensity emanating from a given 6 source 28. A request to switch operative modes of the apparatus, indicated by arrow 44, is sent to the receiving station 30. Typically such a request 44 is encrypted and, or password protected. Upon receiving the request 44 and verifying it's authenticity the receiving station 30 sends the necessary switching signal 42 to the apparatus 10. The information relating to radiation intensity is then relayed to the interested party 34 in the manner described above.
When the apparatus 10 is in the first operative mode the receiving station 3 0 can test the apparatus 10 by sending a switching signal to check that the apparatus 10 responds and that information relating to radiation intensity is subsequently received therefrom. Such testing may be conducted randomly or at predetermined time intervals. If no response is received from the apparatus 10, the receiving station 30 then alerts the interested party 34 that the apparatus 10 needs to be checked. The receiving station 30 may also transmit a signal to the apparatus 10 which has the effect of changing the limit at which the alarm signal is triggered in the first operative mode.
As described above, the apparatus 10 includes motion sensors 22 which are armed after the apparatus 10 has been installed. If the apparatus 10 is subsequently moved or an attempt is made to open the casing 12 to tamper with the internal components, the motion sensors 22 generate an appropriate alarm signal which is relayed to the receiving station 30 by the wireless communication means 18. The interested party 34 is then informed that the apparatus 10 has been disturbed. For the purposes of maintenance or inspection the motion sensors 22 can be temporarily disarmed, for example by a signal sent from the receiving station 30 or on-site by the use of, for example, a key.
While the above embodiment of the invention relates to the monitoring of electromagnetic radiation emanation from a source such as a telecommunications mast, the apparatus 10 may be configured so as to monitor the cumulative effect of electromagnetic radiation from a plurality of sources. For example, there has been much debate regarding the possible effects of electromagnetic radiation emanating from overhead power lines and electricity substations. The apparatus may be configured so 1 1 1.
7 as to monitor electromagnetic radiation at different frequencies and from different sources and to provide an alarm signal when an overall safe limit has been equalled or exceeded.