1. A method comprising in a radio communication network infrastructure:
acquiring a message from a terminal device indicating communication quality below a determined threshold in a radio connection between the radio communication network infrastructure and the terminal device;
detecting, in response to said acquiring the message, presence of an intentional radio interference source, wherein the detection is based on at least one measurement report received from the terminal device; and
upon a result of said detection of the intentional radio interference source, causing transmission of a notification message to a determined target entity.
2. The method of claim 1, wherein the detection is based on analysing at least one metric derived from a signal strength of a downlink signal received by the terminal device wherein the at least one metric is comprised in the at least one measurement report received from the terminal device.
3. The method of claim 2, wherein the analysis comprises comparing the value of the at least one metric with a downlink signal quality reported by the terminal device and, upon determining that the at least one metric indicates downlink signal strength higher than what is proportional to the estimated path loss and transmission powers, determining that the terminal device is subject to the intentional radio interference.
4. The method of claim 2, wherein the at least one metric comprises at least one of the following: downlink signal quality, received signal strength, and path loss.
5. The method of claim 1, wherein the detection is based on analysing at least one metric derived from signal strengths of a plurality of downlink signals received by the terminal device from different base stations of the radio communication network infrastructure, wherein said at least one metric is comprised in the at least one measurement report received from the terminal device.
6. The method of claim 5, wherein the analysis comprises comparing said at least one metric with a determined threshold and determining, if a determined number of metrics exceed the determined threshold, that the terminal device is subject to the intentional radio interference.
7. The method of claim 1, wherein the terminal device is in a connected state with respect to the radio communication network infrastructure at the time of launching the detection of the presence of the intentional radio interference source.
8. The method of claim 1, wherein said at least one measurement report comprises at least one measurement report received from the terminal device after launching the detection of the presence of the intentional radio interference source.
9. The method of claim 1, wherein the detection is based on analysis of measurement data history associated with the terminal device.
10. The method of claim 9, wherein the analysis of the measurement data history comprises searching for a rising edge in signal strength measurements and, upon detecting a rising edge, determining that the intentional radio interference source is present.
11. The method of claim 1, further comprising upon determining that the intentional radio interference source is present: determining (802) a location of the terminal device and determining a context of the intentional radio interference on the basis of the determined location of the terminal device.
12. The method of claim 1, wherein the notification message triggers an alarm.
13. The method of claim 1, wherein the target entity comprises at least one of the following: an emergency centre, a security service entity, a public safety entity, and an insurance entity.
14. An apparatus for a network element of a radio communication network infrastructure, the apparatus comprising means for carrying out all the steps of the method according to claim 1.
15. A computer program product embodied on a distribution medium readable by a computer and comprising program instructions which, when loaded into an apparatus for a network element of a radio communication network infrastructure, execute the method according to claim 1.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for measuring a deviation of a member from a joint target position in a spark plug, comprising the steps of:
joining a member to a measuring object having an end face at a position other than an axis of the measuring object on the end face;
engaging the measuring object with a female thread jig having a reference surface in which a reference portion serving as a reference for the joint target position of the member in the measuring object is formed;
detecting at least one predetermined measuring point in a projection image of a front end portion of the member when the front end portion is projected on a flat measurement face including the reference surface, while the measuring object is engaged with the female thread jig;
detecting the reference portion on the measurement face; and
measuring a deviation of the member from the joint target position based on an angle between a straight line that connects the axis of the measuring object to the measuring point on the measurement face and a reference straight line that connects the axis of the measuring object to the reference portion on the measurement face,
wherein the deviation is confirmed in numerical terms by analyzing and calculating data obtained from the projection image.
2. The measuring method according to claim 1,
wherein the measuring object is a metallic shell for a spark plug, and the member is a ground electrode joined to the metallic shell.
3. The measuring method according to claim 1,
wherein measuring points include a predetermined first measuring point and a second measuring point on an outer edge of the projection image of the front end portion, the method for measuring a deviation further comprising the steps of:
calculating a center of the projection image of the front end portion based on: a piece of first angle information representing an angle between the reference straight line and the first straight line that connects the axis of the measuring object and the first measuring point, and a piece of second angle information representing an angle between the reference straight line and the second straight line that connects the axis of the measuring object and the second measuring point;
finding a third straight line that connects the axis of the measuring object to the thus-calculated center of the projection image of the front end portion, and:
measuring the deviation of the member from the joint target position based on a third angle information representing an angle between the reference straight line and the third straight line.
4. The measuring method according to claim 3,
wherein the projection image of the front end portion assumes an approximately rectangular shape having four vertices, and
wherein the first measuring point and the second measuring point are represented by two vertices that are closer to the axis of the measuring object than other vertices found in the projection image of the front end portion.
5. The measuring method according to claim 3,
wherein the first straight line and the second straight line are circumscribed at different locations on the outer edge of the projection image of the front end portion, respectively.
6. The measuring method according to claim 1,
wherein the axis of the measuring object is detected before the measurement of the deviation of the member from the joint target position, based on a chamfered portion formed in a boundary of the reference surface of the female thread jig and a thread hole.
7. The measuring method according to claim 1,
wherein, in the engaging step, the measuring object is engaged with the female thread jig with a predetermined torque.
8. A method for manufacturing a spark plug comprising the steps of:
joining a ground electrode to an end face of a cylindrical metallic shell;
engaging the metallic shell joined to the ground electrode with a female thread jig having a reference surface where a reference portion that serves as a reference of a joint target position of the ground electrode in the metallic shell is formed beforehand;
detecting at least one predetermined measuring point in a projection image of a front end portion of the ground electrode when the front end portion is projected on a flat measurement face including the reference surface, while the metallic shell is engaged with the female thread jig;
detecting the reference portion on the measurement face;
measuring a deviation of the ground electrode from the joint target position based on an angle between a straight line that connects the axis of the metallic shell to the measuring point on the measurement face and a reference straight line that connects the axis of the metallic shell to the reference portion on the measurement face;
judging whether or not the measured deviation is within a predetermined allowable range;
fitting an insulator where a center electrode and a terminal fitting are assembled to the metallic shell in which the deviation is judged to be within the allowable range; and
forming a front end of the ground electrode so as to face the center electrode,
wherein the deviation is confirmed in numerical terms by analyzing and calculating data obtained from the projection image.
9. The measuring method according to claim 1,
wherein the deviation is measured using a scale.
10. The measuring method according to claim 9,
wherein the scale is an operational unit that analyzes and calculates projection image data.
11. The measuring method according to claim 10, further comprising the steps of:
generating projection image data;
analyzing the projection image data to detect the predetermined measuring point; and
analyzing the projection image data to detect the reference portion on the measurement face.