JPH11316269A - Dgps positioning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow DGPS positioning with sure in short time after a power source is turned on. SOLUTION: DGPS information broadcasted with FM multiplex is received with an FM multiplex broadcast receiver, which is inputted in a navigation device 21, and the position measured with GPS is corrected, based on the DGPS information. The FM multiplex broadcast receiver saves a station information of a DGPS station which can be received in a memory 15 which keeps data after a power source is turned off, and gets DGPS information by receiving DGPS station which is preserved at power-on, and the navigation device 21 corrects a position obtained by GPS positioning, based on the DGPS information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DGPS positioning method, and more particularly, to a method for transmitting DGPS information broadcast by FM multiplexing to FGPS.
The present invention relates to a DGPS positioning method for receiving an M multiplex broadcast receiver, inputting the received signal to a navigation device, and correcting a position measured by GPS based on DGPS information.

[0002]

2. Description of the Related Art In a navigation system for guiding a vehicle to a destination, it is important to accurately grasp the position of the vehicle and to correctly recognize road traffic information (traffic jam, accident, regulation, etc.). Currently, the vehicle position is determined by (1) self-contained navigation using a distance sensor such as a vehicle speed sensor or a direction sensor such as a gyro, and (2) GPS (Global Positioning System) that receives position information from satellites.
Navigation is also used. GPS position accuracy is bad 100
m or more. For this reason, it is required to improve the positional accuracy of GPS, and DGPS (Differen
tial Global Positioning System) has been proposed and put into practical use. DGPS (1) receives GPS satellite radio waves at a location where the exact position is known, measures the position, (2) determines the difference (error) between the known position and the measured position, and (3) determines the same in the same area. By transmitting the determined error or correction coefficient (DGPS information) to the positioning system user, the position accuracy and reliability of the positioning system are improved and secured (DGPS positioning). (4) The DGPS is provided to the user. As a means for transmitting information, FM multiplex broadcast radio waves are used.

[0003] Road traffic information (traffic jams, accidents, regulations, etc.)
Is provided by a road traffic information communication system (VICS), and an on-vehicle navigation system receives road traffic information (VICS information) and displays it on a map in real time. By using the VICS road traffic information, the driver can reach the destination in a short time while avoiding congested roads, traffic restricted roads, and accident roads. As means for communicating such VICS information,
Currently, optical beacons, radio beacons, and FM multiplex broadcast radio waves are used. The communication area of each communication means is 10 to 50 km per FM multiplex broadcasting, 60 to 70 m per radio beacon, and 3.5 m per optical beacon.
It is. For this reason, FM multiplex broadcasting having a wide communication area flows high-frequency traffic information, and radio beacons and optical beacons flow traffic information in a limited area.

FIG. 5 is a diagram showing the structure of FM multiplexed data multiplexed in FM broadcasting. Each frame is composed of 272 blocks (packets), 190 blocks of 272 blocks transmit data blocks and 82 blocks transmit only parity. In the parity block, the parity block is dispersedly arranged in the data block. One frame is 4.896 seconds, and one block is 18 msec. Each data block is a 16-bit block identification code BI
It is composed of C (Block Identify Code), 176-bit data, 14-bit CRC code, and 82-bit parity (horizontal code) for error detection and correction. The parity block is a 16-bit block identification code BI.
C, a 190-bit parity (vertical code), and an 82-bit parity for error detection and correction (horizontal code). The identification code of the data block in the first 13 blocks is BIC1, the identification code of the data block in the next 123 blocks is BIC3, the identification code of the data block in the next 13 blocks is BIC2, and the last Among the 123 blocks, the identification code of the data block is BIC3, and the identification code of the parity block is BIC4.

[0005] Block synchronization can be achieved by detecting the block identification code for each block.
Every two blocks (the block identification code BIC4 followed by BI
Frame synchronization can be achieved (by detecting C1). Further, since parity (vertical code, horizontal code) for error detection and correction is included, error detection and error correction processing (vertical correction, horizontal correction) can be performed using these parities. Further, since the data block contains a CRC code, a CRC check can be performed for each block. The VICS information is transmitted using all blocks of the frame, while the DGPS information is transmitted using the first two blocks of the frame.

FIG. 6 shows a block structure of DGPS data, which shows a format of a 176-bit data block (a 190-bit data block in FIG. 5 excluding a 14-bit CRC block), and a 16-bit prefix. 51 and 160-bit and 144-bit DGPS segments 52 and 53 and 16-bit CRC
54. The prefix 51 includes service identification data for identifying program contents, a decoding identification flag for specifying a decoding method of an error correction circuit ("1" is decoding only in the horizontal direction, "0" is horizontal, vertical, and horizontal decoding). FIG.
Is the segment configuration of the DGPS information. The DGPS segment is composed of 304 bits of 160 + 144 bits, and the first 16 bits are as follows. (1) Segment identification: 1101 (D) (2) Segment length: 1111 (F) ( 3) Extended segment length: 00100100. From the above, the prefix 51 and the next 1
DGPS information can be identified by referring to 6 bits.

At present, the DGPS information is transmitted by the FM multiplex station of the JFN sequence, and the VICS information is transmitted by the FM multiplex station of the NHK sequence. The GPS information and the FM information are appropriately switched by switching one FM multiplex broadcast receiver. The DGPS information is received. Therefore, in order to receive DGPS information and correct GPS position information, it is necessary to receive JFN sequence FM multiplex broadcasting.

FIG. 8 shows a conventional processing flow after power is turned on. When the power is turned on, the FM multiplex broadcast receiver initializes internal memories and performs a setup process so that communication with the navigation device is possible (step 101). Next, a search is made for FM multiplex broadcasting stations whose received electric field strength is equal to or higher than a set level by seek control, and a multi-station list is created by identifying whether the FM multiplex broadcasting station is a JFN sequence (DGPS station) or an NHK sequence. (Step 102). This list of multiplex stations is used to receive another FM multiplex broadcast station having a good reception state when the reception state of the currently multiplexed FM multiplex broadcast station deteriorates. Then
Channel selection is performed (step 103). If a JFN sequence is selected, DGPS information is received and input to the navigation device (steps 104 and 105), and the navigation device corrects the GPS positioning position based on the DGPS information. (Step 106). On the other hand, when the NHK sequence is selected by tuning, the VICS information is received and displayed, and the information is input to the navigation device (step 10).
7), the navigation device uses the information for route calculation and the like, and performs navigation control based on the GPS positioning position (step 108).

[0009]

As described above, if the JFN sequence is not selected after the multi-station list is created,
If the N series is not selected, DGPS positioning cannot be performed, so that the vehicle position cannot be accurately detected, and the vehicle position mark on the monitor of the navigation device is shifted from the actual vehicle position. The displayed position jumps. Even when the JFN sequence is selected after the multi-station list is created, it takes about one minute to create the multi-station list, so that if the own vehicle moves during that time, a position jump problem occurs. . In view of the above, an object of the present invention is to provide a DGPS that can perform DGPS positioning in a short time after power-on and reliably
It is to provide a GPS positioning method.

[0010]

SUMMARY OF THE INVENTION According to the present invention, there is provided a GPS receiver for receiving DGPS information broadcasted by FM multiplex, inputting the received DGPS information to a navigation device,
DG that corrects the position measured by GPS based on DGPS information
In the PS positioning method, the station information of the receivable DGPS station is stored in a memory that can be held even after the power is turned off, the DGPS station stored at the time of power on is received to obtain the DGPS information, and based on the DGPS information, By modifying the position information obtained from the GPS.

[0011]

FIG. 1 is a block diagram of an FM multiplex broadcast receiver according to the present invention. The FM multiplex broadcast receiver receives the FM broadcast signal, separates and demodulates the FM multiplex broadcast data such as VICS information, DGPS information, and text information transmitted by being multiplexed with the FM broadcast signal and passing the data to the navigation system. Or on a display device. In the drawing, reference numeral 1 denotes an antenna, and 2 denotes a front end (F / E), which includes an antenna tuning circuit, a high-frequency amplifier circuit, a local oscillator, a mixer, and the like (not shown). 3 is a PLL circuit, 4 is a low-pass filter, 5 is an intermediate frequency amplification / FM detector (IF /
DET). The PLL circuit 3, the low-pass filter 4, and the local oscillator built in the front end 2 constitute an electronic tuning device, and oscillates the local oscillator at a frequency corresponding to the reception frequency (the frequency of the FM broadcasting station selected by the tuning operation). The intermediate frequency signal is output by a mixer in the front end 2. 6 is a noise canceller / stereo demodulation circuit (N
C / MPX) and 7 are filter circuits for extracting an L-MSK modulated signal component from the FM detection signal. Thus, a tuner is formed.

8 indicates whether VICS information is being received or DGP
A switching circuit for switching the output direction depending on whether S information is being received, 9 is a multiplex decoder for VICS, 10 is a multiplex decoder for DGPS, 11 is a processor (CPU).
A memory for controlling reception of ICS information / DGPS information, display control of character information, channel selection control, and the like. A memory 12 stores a multiplex station list and received FM multiplex data (VICS information, DGPS information, text broadcast program information, etc.). , 13 is an operation unit for the user to select a channel or select a desired teletext program, 14 is a display device for displaying text information (news, weather forecast, etc.) on the screen, and 15 is a display device even after the power is turned off. Retainable memory (non-volatile memory)
It stores station information of GPS stations. Note that the multiplex station list is a list indicating station frequencies of FM multiplex broadcasting stations whose reception electric field strength is equal to or higher than a set level, and distinction between JFN sequence / NHK sequence and the like. 21 is a navigation device, 22 is a GP
S receiver. The navigation device 21 measures the position of the own vehicle based on the GPS information received by the GPS receiver 22 (GPS positioning), and performs G based on the DGPS information.
It has a function of correcting the PS positioning position (DGPS positioning function).

FIG. 2 (a) is a block diagram of the VICS multiplex decoder 9. Reference numeral 31 denotes an L-MSK demodulation circuit which performs delay detection on the L-MSK modulated signal to reproduce a bit clock and demodulate a bit data sequence. Reference numeral 32 denotes a synchronization circuit for detecting block synchronization and frame synchronization; 33, a correction processing unit; and 34, a one-frame RAM for storing VICS information.
The correction processing unit 33 includes a CRC check unit 33a and an error detection and correction unit 33b that performs horizontal correction / vertical correction, and sends a correction result to the CPU 11. The CRC check unit 33a performs a CRC check for each block, and performs an error detection and correction unit 33b.
Performs horizontal and vertical error correction on the bit data string based on the block synchronization and frame synchronization detection signals input from the synchronization circuit. FIG. 2B is a configuration diagram of the multiplex decoder 10 for DGPS. In the figure, 41 is an L-MSK demodulation circuit, 42 is a synchronization circuit, 43 is a correction processing unit, and 44 is DGP
This is a RAM that stores S information, and has a configuration similar to that of FIG. However, the error detection and correction unit 43 uses the DGP
Only horizontal correction is performed on S information, and the correction result is
Send to 1.

FIG. 3 is a flow chart of a process for storing DGPS station information. It is assumed that a multi-station list is created every predetermined time (for example, every 15 minutes). CPU of FM multiplex broadcast receiver
11 checks whether it is time to create a multiplex station list (step 201), and if it is not a multiplex station list creation timing, the VI multiplexed into the currently multiplexed FM multiplex broadcast.
The CS information or the DGPS information is received, and the transmission, storage, display, and the like to the navigation device are controlled (step 202), and if the power is not turned off (step 20).
3) Return to step 201 and repeat the subsequent processing.

On the other hand, in step 201, when it is time to create a multiplex station list, an FM multiplex broadcast station whose reception electric field strength is equal to or higher than a set level is searched by seek control so as not to affect the voice currently being received. A multi-station list is created by identifying whether the FM multiplex broadcasting station is a JFN sequence (DGPS station) or an NHK sequence (step 2).
04). Next, the multi-station list, the station frequency list of the DGPS station, or the DG having the highest received electric field strength is used.
Any station frequency of the PS station is stored in the non-volatile memory 15 (step 205), and the processing from step 201 onward is repeated. As described above, the station frequency of the receivable DGPS station is always stored in the non-volatile memory 15, so that the station frequency information of the DGPS station is preserved even when the power is turned off.

FIG. 4 shows a processing flow of the present invention after the power is turned on. When the power of the FM multiplex broadcast receiver is turned on, FM
The multiplex broadcast receiver initializes built-in memories and performs a setup process so that communication with the navigation device is possible (step 301). Then, CPU
11 acquires the station frequency of the DGPS station stored in the nonvolatile memory 15 (step 302), and selects the DGPS station (step 303). Thereafter, the CPU 11 receives the DGPS information multiplexed from the DGPS station and notifies the navigation device 21 of the information. This allows
The navigation device 21 corrects the GPS positioning position based on the DGPS information (DGPS positioning), and performs navigation control based on the DGPS positioning position (Step 30).
4). After notifying the DGPS information, the CPU 11 of the FM multiplex broadcast receiver creates a multiplex station list by seek control (step 305), and thereafter performs the same control as in the related art.

As described above, the station information of the receivable DGPS station is stored in the non-volatile memory,
Since a GPS station is selected, DGPS information is received and DGPS positioning is performed, a short time after power-on, and
DGPS positioning can be reliably performed, and correct navigation control can be performed. Currently, the only stations that multiplex broadcast DGPS information are all stations in the JFN sequence. However, in the future, local independent stations (not JFN or NHK affiliates) will also multiplex broadcasts. Therefore, the DGPS multiplex broadcasting station is not limited to the JFN sequence. Also, FIG.
, The FM multiplex broadcast receiver is configured by separately providing a multiplex decoder for VICS and a multiplex decoder for DGPS.
It is also possible to configure so that one decoder decodes VICS information and DGPS information. As described above, the present invention has been described with reference to the embodiments. However, the present invention can be variously modified in accordance with the gist of the present invention described in the claims, and the present invention does not exclude these.

[0018]

As described above, according to the present invention, the receivable DGP
The station information of the S station is stored in a memory that can be held even after the power is turned off, and the DGPS station stored when the power is turned on is
GPS information is acquired, and GPS information is obtained based on the DGPS information.
Since the location information obtained from is corrected, DGPS positioning can be performed quickly and reliably after turning on the power,
Accurate navigation control without skipping positions.
Also, even if the FM multiplex broadcast receiver is set to VICS reception after power-on, accurate navigation control can be performed by DGPS positioning regardless of the setting.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an FM multiplex broadcast receiver of the present invention.

FIG. 2 is a configuration diagram of a multiplex decoder.

FIG. 3 is a flowchart of processing for storing DGPS station information.

FIG. 4 is a processing flow after power-on.

FIG. 5 is a diagram illustrating a frame configuration of FM multiplexed data.

FIG. 6 is a configuration diagram of DGPS data.

FIG. 7 is a diagram illustrating the contents of a DGPS segment.

FIG. 8 is a conventional processing flow after power-on.

[Explanation of symbols]

9 Multiplex decoder for VICS 10 Multiplex decoder for DGPS 11 Processor (CPU) 15 Memory (non-volatile memory) that can be retained even after power off 21 Navigation device 22 GPS receiver

Claims (1)

[Claims] 1. DGPS information broadcast by FM multiplexing is
A DGPS positioning method for receiving an M-multiplex broadcast receiver, inputting the received information to a navigation device, and correcting a position measured by GPS based on DGPS information, wherein a memory capable of holding station information of receivable DGPS stations even after power-off. The DGPS station saved at power-on is received and the DGP
A DGPS positioning method, comprising acquiring S information and correcting position information obtained from GPS based on the DGPS information.