JPH10262005A - Reception level measurement device and measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a center value from being affected by the large drop in a reception level, while a measurement vehicle is stopped at the time of checking the conditions of the base station service area of a PHS. SOLUTION: Whether or not the measurement vehicle is in an almost stopped state (S1), the reception level of radio waves from a base station is measured (S3) at the reception timing (fixed time interval) of burst waves to be measured when it is not a stopped condition (S2) and whether or not a measurement section is moved is checked (S4). When it moves, the center value of the reception level measured value of the section is computed (S5) and recorded (S6). When the measurement vehicle is in the almost stopped state in a step S1, the reception level is not measured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cellular phone and a PHS
The present invention relates to a reception level measurement device and a measurement method applied to measurement of a distribution of reception levels of base station radio waves in a service area of a base station such as a (personal handy phone system).

[0002]

2. Description of the Related Art In order to investigate a service area of a base station, a reception level of a radio wave from the base station is measured.
In general, when measuring while moving the reception level, the reception level fluctuates drastically. Therefore, the service area of the base station can be correctly grasped by using the averaged reception level.
For this reason, the median of the reception level is obtained for each fixed distance. For example, while driving the measuring car, the reception level is set to 10c.
Measurement is performed for each m, and the median of the reception level for each 10 m section is obtained and recorded. Such a method is preferable when the radio wave is continuously transmitted and the reception level of the radio wave can be sampled at a certain distance.

However, the radio waves transmitted from the base station are not continuous,
If the transmission is performed in bursts at regular intervals, the reception level cannot be sampled at short distance intervals depending on the traveling speed of the measuring vehicle. For example, if a base station radio wave transmitted at intervals of 100 ms is received while traveling at a speed of 36 km / h, a reception level can be obtained only at intervals of 1 m. The higher the traveling speed, the longer the intervals at which reception is possible. In such a case, in order to increase the number of samples, it is better to receive all the radio waves from the base station in accordance with the burst wave reception timing instead of determining the distance interval for sampling.

As shown in FIG. 4, in a conventional reception level measuring device, the level measuring section 11 receives all the radio waves from the base station in accordance with the burst wave receiving timing, and the moving distance of the measuring vehicle is the distance. Each time the detected moving distance reaches a predetermined value, for example, 10 m, the median value of the reception level measured during the predetermined distance is calculated by the median value detecting unit 13 and the calculated median value is calculated. Is recorded in the recorder 14.

[0005]

Although this conventional measuring device has no problem when the measuring vehicle runs at a constant speed, it causes a problem when the vehicle is temporarily stopped during measurement due to a traffic signal at a road intersection or the like. The measurement of the reception level is continued during the pause, the number of samples of the reception level at the point where the reception was stopped increases, and the median value cannot be obtained as an average value over a certain distance. The reception level fluctuates drastically in place, and the reception level may drop by about 20 dB depending on the place. The median value at which the temporarily stopped place is such a place where the reception level is extremely low does not correctly represent the reception level in the measurement distance section.

SUMMARY OF THE INVENTION It is an object of the present invention to accurately obtain an average value in a measurement section for each fixed distance, without reducing the number of samplings of the reception level and without causing a measurement error due to a temporary stop of the measurement vehicle. A measuring instrument and a measuring method are provided.

[0007]

According to the measuring instrument of the present invention, the receiving level is periodically measured, the moving speed of the measuring instrument is detected by the speed sensor, and the receiving speed is detected when the detected speed is equal to or less than the predetermined value. Means are provided for preventing the level measurement from being input to the median detection means. This blocking means stops the measurement of the reception level measurement means or performs the measurement of the reception level measurement means, but does not supply the measured value to the median value detection means.

According to the measuring method of the present invention, the reception level is acquired at fixed time intervals, and the median of the acquired reception levels is calculated for each measurement distance. When the value becomes equal to or less than the value, the reception of the reception level is stopped.

[0009]

FIG. 1 shows a functional configuration of an embodiment of a measuring instrument according to the present invention. The level measuring section 11 measures the reception level of the radio wave of the frequency set in the frequency setting section 21 and outputs an analog voltage corresponding to the reception level. The analog voltage is output from the A / D converter 22 at regular time intervals.
That is, it is sampled in synchronization with the timing of the received burst wave and converted into digital data. The data is converted into digital data and supplied to the median value detector 13. The time slot of the burst wave to be received, that is, the ID of the base station that is transmitting the burst wave to be received is set in the level measurement unit 11, and A /
The D converter 22 may perform a sampling operation.

On the other hand, the moving distance of the measuring vehicle is determined by the distance sensor 12.
Is detected by A measurement section length set in the section length setting section 23, for example, 10 m, is input to the distance sensor 12, and a calculation command is input to the median value detection section 13 every time the movement distance detected by the distance sensor 12 becomes the measurement section length. , The median value detection unit 13 calculates the median value of the sampling value data of the reception level input in that section. The distance sensor 12
For example, a pulse is generated in conjunction with the rotation of the wheel 24 of the measuring vehicle, and a first pulse is generated every time the measuring vehicle moves by a certain length, for example, 10 cm, and the generation of the first pulse is set. Each time the number corresponding to the section length is reached, the second
It generates a pulse, that is, a calculation command. For example, as shown in FIG. 2A, a first pulse is generated, and as shown in FIG. 2B, a second pulse (computation command) is generated every three first pulses.

In the present invention, the moving speed of the measuring vehicle is detected by the speed sensor 25. The stop speed set in the stop speed setting unit 26 is input to the speed sensor 25, and a stop signal is output when the speed detected by the speed sensor 25 falls below the set stop speed. The measurement of the reception level is stopped while the stop signal is obtained. For example, a stop signal is supplied to the A / D converter 22 and the A / D converter 22
Is stopped, and the reception level median value detecting unit 13 is stopped.
From the median value detection unit 13, the measurement of the reception level is stopped while the stop signal is being generated.

When pulse generating means driven by wheels 24 is used as the distance sensor 12 as in this embodiment,
A speed sensor 25 every predetermined time T ₀ as shown in FIG. 2C setting, first counted as shown in the total number of pulses (Fig. 2D) which is generated by the distance sensor 12, which is a predetermined number, i.e. the setting unit 26 If the number is less than the number corresponding to the set stop speed, a stop signal is generated as shown in FIG. 2E. FIG.
In the example, the stop signal is generated when the number of the first pulses within the time T ₀ is zero.

A position detector 27 such as a GPS (Global Positioning System) is provided to detect the position of the measuring vehicle.
When the median value is calculated by the median value detection unit 13, the median value is recorded on the recorder 14 in association with the measured position at that time. As shown in FIG. 3, in the processing of the measuring method of the present invention by the measuring device described above, it is checked whether the moving speed of the measuring vehicle is equal to or less than a predetermined value (S1).
It is checked whether a predetermined time has elapsed (S2). When the predetermined time has elapsed, that is, at the timing of receiving the burst wave, the reception level is measured (S3), and it is checked whether the measurement distance has been moved (S4). If it has not moved the predetermined distance, the flow returns to step S1. If the predetermined distance has elapsed, the median value of the reception level measurement value in that section is calculated (S5), and the median value is recorded together with the position information. To return to step S1 (S6).

If the moving speed is equal to or lower than the predetermined value in step S1, that is, if the moving speed is substantially zero, the reception level is not measured. The data recorded by the recorder 14 is read out after the measurement of the required reception level is completed, and the computer displays a running locus on the electronic map on the electronic map by the read position data, and reads out each of the readouts. The median value is displayed in a color-coded manner at the position of the position data, so that the situation of the service area of the base station can be visually and intuitively understood. It should be noted that the speed sensor 25 may be of another type, such as a type that obtains a speed from an accelerometer.

[0015]

As described above, according to the present invention, even when the measuring vehicle is stopped or the speed is extremely low, even if there is a large drop in the reception level, the drop data is transmitted to the stop signal. Is not used for the calculation of the median value, that is, such a reception level is not measured from the viewpoint of the calculation of the median value. Therefore, the median value in the measurement section can be correctly obtained without being affected by the drop. If the vehicle is running at a speed higher than the set speed, the reception level is measured at a constant time interval (burst wave reception timing), and there is no possibility that the data amount is insufficient for finding the median value.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a functional configuration of an embodiment of a measuring instrument according to the present invention.

FIG. 2 is a diagram showing an example of a pulse generated by a distance sensor, a calculation command, and a stop signal of a speed sensor.

FIG. 3 is a flowchart showing a processing procedure of the measuring method of the present invention.

FIG. 4 is a block diagram showing a conventional measuring device.

Claims (3)

[Claims] 1. A level measuring means for periodically measuring a reception level of a radio wave transmitted from a base station, a distance sensor for detecting a moving distance of a measuring device, and a speed sensor for detecting a moving speed of the measuring device. A calculation command generating means for generating a calculation command when the detection movement distance of the distance sensor reaches a predetermined value; and calculating the median value of the measured values of the reception levels obtained from the previous calculation command when the calculation command is generated. A reception level measuring device comprising: a median value detection unit that performs a stop signal generation unit that generates a stop signal when the moving speed is equal to or less than a predetermined value; and a unit that stops measuring the reception level during the stop signal. 2. The distance sensor is means for generating a first pulse each time the measuring device moves by a predetermined value, and the calculation command generating means performs the calculation each time the generation of the first pulse reaches a predetermined value. Means for generating a command, wherein the stop signal generating means counts the total number of the first pulses for each predetermined time, and generates the stop signal when the total number is equal to or less than a predetermined value. The reception level measuring device according to claim 1. 3. A reception level of a radio wave transmitted from a base station is periodically measured, and each time the mobile station moves by a predetermined value, a median value of the reception level measurement value during the movement is obtained, and this value is recorded. Detecting the reception level and stopping the measurement of the reception level when the detected moving speed is equal to or lower than a predetermined value.