KR20070002673A - Test method of agps - Google Patents

Abstract

A method for testing performance of an AGPS(Assisted Global Positioning System) receiver is provided to secure the environmental condition equal to a hot start and to simply measure TTFF(Time To First Fix) of the AGPS receiver by supplying assist information without an expensive reference board for receiving a GPS satellite signal. A method for testing performance of an AGPS receiver(420) deciding the position by receiving assist information including ephemeris data, position, and time information from a server, includes steps of: selecting a GPS satellite scenario at a predetermined position for a predetermined time, extracting the ephemeris data at regular time intervals, and storing the extracted ephemeris data and a position value as test data; executing a cold start test of the correspondent APGS receiver; extracting UTC(Universal Time Coordinated) time obtained by the cold start driving of the AGPS receiver if TTFT is detected during cold starting of the AGPS receiver; selecting ephemeris data of the time slot same as the extracted UTC time from the stored ephemeris data; demanding to determine the position by inputting the selected ephemeris data, the position where the ephemeris data is obtained, and the extracted UTC time to the AGPS receiver; and measuring a TTFF value until the position is determined in the correspondent AGPS receiver after demanding to determine the position.

Description

Performance Test Method of A.G.PS Receivers {Test method of AGPS}

1 is a block diagram illustrating a general AGPS system.

2 is a general operational flow of an AGPS receiver.

3 is a block diagram schematically illustrating a test apparatus of a conventional AGPS receiver.

4 is a block diagram of an apparatus for performing a performance test method of an AGPS receiver according to the present invention.

5 is a flowchart illustrating a performance test method of an AGPS receiver according to the present invention.

The present invention relates to a performance test method of an AGPS receiver capable of testing the performance of an AGPS receiver by providing all the information necessary for the AGPS performance test without having a reference board receiving GPS satellite signals.

Currently, positioning technology using a GPS (Global Positioning System) satellite has been widely used in various fields such as vehicle and ship navigation systems, and mobile communication terminals. Position determination using GPS satellites tracks a GPS satellite signal at a user who wants to measure a location, acquires necessary information from the received GPS satellite signal, and then uses the extracted user information based on the extracted information. The step of navigating is to fix the current location of the user. The user equipment that performs this process is called a GPS receiver.

In the above process, the time taken to determine the position by analyzing the satellite signal received from the GPS receiver is called TTFF (Time To First Fix), which is one of the important indicators of the performance of the positioning equipment. An AGPS (Assisted Global Positioning System) has been proposed to solve the power consumption problem of the TTFF and the receiver.

Referring to FIG. 1, the AGPS system includes an AGPS receiver 10, a satellite 20, a mobile communication network 30, a positioning server (also referred to as a PDE) 40, and a reference station GPS receiver 50. As shown in FIG. 2, the AGPS receiver 10 requests Acquisition Assistance Information (AA) data for acquiring a GPS satellite signal to the positioning server 40 (S201). In this case, the positioning server 40 generates the required AA data using the reference station GPS receiver 50 (S202), and then transfers the data to the AGPS receiver 10 (S203). ) Measures the pseudo range of the GPS satellite based on the received AA data (S204), and calculates the position of the current AGPS receiver based on this (S205).

 In addition, satellite information that can be obtained from GPS satellites includes Ephemeris, satellite orbit information for accurate position and velocity calculations, and Almanac, satellite orbit information used for approximate position and velocity calculations. Approximately 15 hours from the time of acquisition, almanac data is valid for approximately 6 weeks from the time of acquisition. A cold start is a case in which the GPS receiver calculates a position in a state where there is no valid upper and almanac data, and a warm start is used to calculate a position using only valid almanac data. In the case where there is both valid almanac data and upper data, the case where the position calculation is performed is called a hot start. Usually, TTFF is long followed by hot start, warm start, and cold start.

Therefore, recently, in order to increase the performance of the AGPS receiver, the AGPS receiver may be provided to the AGPS receiver through a separate server (for example, a positioning server) so that the AGPS receiver can always be hot started.

In the case of such an AGPS receiver, when performing a performance check to determine a location within a limited time, the assist information should be provided to the AGPS receiver, which is the inspection target, instead of the positioning server 40 described above.

To this end, the existing AGPS receiver performance test system, as shown in Figure 3, has a reference board (320) for receiving the actual GPS satellite signal, in addition, the analysis program 311 and the test program 312 ) And a test device 310 having an initialization program (PSS) 313 for driving the reference board 320.

That is, after driving the reference board 320 using the initialization program 313 to receive the actual GPS satellite signal, the received GPS satellite signal is processed to obtain necessary assist information, and the AGPS receiver 300 to be inspected. ), And then measure TTFF.

Accordingly, the test apparatus 310 drives the port P1 for receiving the output signal of the GPS receiver 300 to be inspected and the reference board 320 to drive the GPS satellite data received from the AGPS test program. A port P3 for receiving the signal 312 and a satellite port received from the port P3 are processed by the AGPS test program 312 to output assist information to the GPS receiver 300. A plurality of ports are required, and a special serial cable for connecting the reference board 320 and the test device 310 is required.

However, since the test device 310 is usually implemented as a personal computer, since the current personal computer usually includes only two serial ports, when testing one GPS receiver 300, a separate multi-port is required. In addition, many difficulties arise in setting the initial communication port. In addition, since the reference board 320 is an expensive device as having a function of receiving and processing GPS satellite signals, it causes an increase in test cost.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above-mentioned problems, and its object is to provide all the information necessary for AGPS performance test without having a reference board for receiving GPS satellite signals so that the performance of the AGPS receiver can be tested. It is to provide a performance test method of AGPS receiver.

As a configuration means for achieving the above object, the present invention provides a performance test method of the AGPS receiver to determine the position by receiving the assist information including the data, the position, the time information from the server,

Selecting a GPS satellite scenario for a predetermined time at an arbitrary location, extracting the earliest data at a predetermined time interval and storing it as test data along with the location value;

Testing a cold start operation of the AGPS receiver;

If the TTFF is measured at the cold start of the AGPS receiver, extracting UTC time acquired by cold start driving of the AGPS receiver;

Selecting period data of the same time zone as the extracted UTC time from the stored period data;

Requesting location determination by inputting assist information including the selected upper data, a location from which the upper data is obtained, and the extracted UTC time to the AGPS receiver; And

And measuring a TTFF value from the position determination request until the position is determined by the corresponding AGPS receiver.

Hereinafter, a performance test method of an AGPS receiver according to the present invention will be described in detail with reference to the accompanying drawings.

The performance test method according to the present invention is for an AGPS receiver that can receive assist information including the interface information from another server, such as the positioning server 40 of FIG. 1, and can always operate in a hot start environment. That is, when the test needs to provide virtual assist information, at this time, the information to be provided requires the interface data, the location, and the UTC time. For accurate testing, the provided interface data and the location data are It must be information that can be provided from the actual satellite.

To this end, the present invention arbitrarily sets a test position, the test impurus data is collected and stored at regular intervals of the impurity data appearing at the set position, and then the test is performed in a hot start environment of the AGPS receiver. To perform this, after performing a cold start test, by providing the AGPS receiver with the UTC time obtained at the AGPS receiver and the earliest data of the obtained UTC time among the stored periodic data to the AGPS receiver for testing, The test environment is provided to enable the test to be performed. In particular, it provides accurate reference data and UTC data that need to be tested without a separate reference board for obtaining GPS satellite information.

In this case, the test system can be implemented only by a general personal computer by including only the collected upper data and a program for performing a test operation according to the procedure described below.

Figure 4 is a block diagram showing a test system to which the performance test method according to the present invention is applied.

As shown in Fig. 4, when testing the performance of the AGPS receiver 420 according to the present invention, a test program 411 programmed to perform the test performance method according to the present invention, and a fixed position set according to the present invention. Performance by connecting the GPS receiver 420 to an input / output port P0 of a personal computer 410 having a value and a DB 412 storing a plurality of periodic data collected for a predetermined time at the fixed position. Test is possible.

The personal computer 410 is generally used. Basically, the personal computer 410 is composed of a RAM and a ROM, and includes a test program according to the present invention, storage means for storing fixed position values and upper data, and a test program stored in the storage unit. Control means for performing a test procedure according to the present invention, an output means for displaying an inspection process and a result such as a monitor or a printer, an input means such as a keyboard and a mouse for inputting user commands and data, and the GPS receiver 420 Interface means for input / output interface with the < RTI ID = 0.0 >

FIG. 5 is a flowchart illustrating a performance test method of an AGPS receiver according to the present invention, and includes a control procedure performed in the test program 411 included in the personal computer 410 of FIG.

Hereinafter, the performance test method of the AGPS receiver of the present invention will be described in detail with reference to FIG. 5.

First, before performing the test, the present invention selects a GPS satellite scenario for a predetermined time at an arbitrarily selected position, and collects and stores the earliess data (S500). The impurity data stored in the step S500 is then used for testing in a state (or environment) such as a hot start of the AGPS receiver, for example, from 12 hours (eg, from 9 am at a specific location). The satellite data of the satellites appearing during the night. The time range of the scenario is arbitrarily set, and is usually set in consideration of the fact that the performance test time of the AGPS receiver is performed during the day.

In addition, it is preferable that the upper data is collected at a time interval shorter than the valid time of the upper data. Usually, the average data is valid for 2 hours, so it is preferable to extract and store the annual data in units of approximately 1 hour.

As shown in FIG. 4, if the AGPS receiver 420 to be inspected is connected, performance test of the connected AGPS 420 is started (S501).

At this time, the performance test of the AGPS receiver 420 is performed after the reset test, wake-up test, cold start test, S / N test is completed AGPS performance test. In the flowchart of FIG. 5, a case in which all of the above tests are performed is described. However, the reset test and the wake-up test may not be necessary depending on the AGPS receiver. In this case, the test step may be omitted.

The reset function is provided in most AGPS receivers, and accordingly, the performance test method of the present invention instructs the connected AGPS receiver 420 to reset first to check whether a normal reset operation is performed (S502). The reset function initializes all data or functions of the AGPS receiver 420. After the reset command, it is necessary to confirm whether the state of the AGPS receiver 420 is initialized.

In addition, when the AGPS receiver 420 is provided with a sleep function to save power, the AGPS receiver 420 is instructed to wake up after a predetermined time in the sleep state, and the AGPS receiver 420 wakes up according to the instruction. It is checked whether up (S503).

Subsequently, a cold start test of the corresponding AGPS receiver 420 is started (S505). The cold start is to calculate the position starting from the tracking of the GPS satellites. After the reset test, the cold start is instructed by the AGPS receiver 420 initialized after the reset test, and the received AGPS receiver 420 tracks the GPS satellites. The time TTFF taken until data acquisition, position calculation, and position fixation is completed is measured (S506).

In this case, the signal-to-noise ratio of the AGPS receiver 420 in cold start operation may be further measured (S505).

When the AGPS receiver 420 operated as a cold start completes the position fixing, the UTC time is extracted from a message indicating time information among the data output from the AGPS receiver 420 (S507). In general, GPS satellite information includes time information for accurate calculation of a location, and a GPS receiver including an AGPS receiver calculates a precise UTC time when calculating a location, and this is a specific message (for example, an RMC message among NMEA messages). To print). Therefore, in the present invention, after the cold start test, the UTC time obtained by the AGPS receiver 420 is extracted to use the next AGPS time.

Next, the AGPS performance test is started with an AGPS receiver (S508), and the imperial data stored in the step (S500) is obtained by using the UTC time extracted from the cold start test. In operation S509, the fixed position value of the corresponding upper data is retrieved.

According to the above, assist information similar to an actual situation is generated, and the assist information, the extracted UTC time, the corresponding upper data, and the fixed position value are generated to the corresponding AGPS receiver 420. Based on the measurement, the time required for the AGPS receiver 420 to fix the position TTFF is measured (S511).

According to the above, the present invention provides the assist information required for the performance test without providing an expensive reference board for receiving the GPS satellite signal for the performance test test for measuring the performance (TTFF) of the AGPS receiver. Providing a start-like environment, it has a good effect of simply measuring the TTFF of the AGPS receiver.

Claims (6)

In the performance test method of the AGPS receiver to receive the assist information including the Emperorse data, location, time information from the server to determine the position, Selecting a GPS satellite scenario for a predetermined time at an arbitrary location, extracting the earliest data at a predetermined time interval and storing the same as the test data along with the location value; Performing a cold start test of the AGPS receiver; If the TTFF is measured at the cold start of the AGPS receiver, extracting UTC time acquired by cold start driving of the AGPS receiver; Selecting period data of the same time zone as the extracted UTC time from the stored period data; Requesting location determination by inputting assist information including the selected upper data, a location from which the upper data is obtained, and the extracted UTC time to the AGPS receiver; And And measuring a TTFF value from the position determination request until the position is determined by the corresponding AGPS receiver. The method of claim 1, wherein the upper data stored as the test data A performance test method for an AGPS receiver, characterized in that extracted from the GPS satellite scenario at any location for 12 hours in units of 1 hour. The method of claim 1, Instructing the AGPS receiver to reset, and performing a reset test to check whether a normal reset operation is performed, And performing the reset test is performed before testing a cold start of an AGPS receiver. The method of claim 1, If the AGPS receiver has a wake-up function, performing a wake-up test for checking whether the AGPS receiver wakes up within a set time in a sleep mode; The performing of the wake-up test is performed before the step of testing the cold star of the AGPS receiver. The method of claim 1, Measuring a signal-to-noise ratio of the reception performance of the AGPS receiver; And measuring the signal-to-noise ratio with a cold start test. The method of claim 1, wherein extracting the UTC time comprises: And extracting UTC time from an NMEA message indicating time information output from the GPS receiver.

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