Car navigation control unit

Abstract

The present invention aims to provide a car navigation control device that prevents errors in car navigation systems, etc., caused by discrepancies between location information between vehicle driving information and GPS positioning information, and by whether or not vehicle location information is determined according to vehicle speed, thereby enabling simultaneous viewing of television and navigation operation. [Solution] In order to solve the above problems, the car navigation control device of the present invention is connected between the vehicle and the car navigation system and comprises a receiving means, a calculation means, a storage means, and a transmitting means, and is characterized in that when the car navigation system detects that the vehicle driving information and the GPS positioning information are different location information at a predetermined vehicle speed or above, or when the vehicle driving information and the GPS positioning information detect a discrepancy in location information under predetermined conditions, the calculation means monitors the elapsed time when the discrepancy occurred and the elapsed time when it was detected that the vehicle speed was above a predetermined speed, and cuts off the GPS signal or the like before the threshold for error occurrence is reached, thereby providing a means for avoiding errors in the car navigation system.

Description

Technical Field

[0001] The present invention relates to a car navigation device (hereinafter referred to as "car navigation") or a driving support function that compares vehicle information (hereinafter referred to as "vehicle travel information") using a vehicle stop signal indicating vehicle stop, a driving pulse signal indicating a driving state, a parking signal, and a CAN or other vehicle data bus line (hereinafter referred to as "CAN etc.") indicating various vehicle states, and positioning information of a global positioning system using positioning satellites (including satellite positioning system (GNSS)) (hereinafter referred to as "GPS") (hereinafter referred to as "GPS positioning information") (hereinafter, "vehicle travel information" and "GPS positioning information" are collectively referred to as "vehicle information"), and avoids stopping or errors (hereinafter referred to as "errors") caused by differences.

Background Art

[0002] Normally, the car navigation is set so that the driver cannot watch videos using a television, optical disk, memory, communication or network (hereinafter referred to as "television etc.") while the vehicle is running. This is to prevent the safety of driving from being reduced by the driver watching videos.

[0003] However, there are cases where passengers in the passenger seat or rear seat may want to watch videos while the vehicle is running. In response to the case where passengers want to watch videos, a device has been developed that is connected to a signal line for transmitting vehicle information from the vehicle to the car navigation and controls so that videos such as a television can be watched even while the vehicle is running.

[0004] Patent Document 1 discloses an in-car television adapter for a car navigation system equipped with a television that works in conjunction with a driver assistance system, enabling television viewing even while the vehicle is in motion without interfering with the functions of the driver assistance system. In Patent Document 1, when the driver assistance system is not operating, the vehicle speed pulse signal (driving pulse signal) received by the television adapter is converted by the analog signal control unit of the television adapter into a signal indicating that the vehicle is stopped, even if it is actually moving, and then transmitted to the analog signal input unit of the car navigation system, thereby enabling television viewing even while the vehicle is in motion.

[0005] However, depending on the car navigation system installed in the vehicle, if it detects that the location information deviates by more than a predetermined threshold when comparing GPS positioning information and vehicle driving information, an error may occur and the navigation settings and operation (hereinafter referred to as "navigation operation") may be stopped. In the TV adapter of Patent Document 1, if a signal indicating that the vehicle is stopped is sent to the car navigation system when the vehicle is actually moving, two different states, "stopped" and "driving," will be detected between the GPS positioning information indicating the actual moving current location and the signal. If two different states, "stopped" and "driving," are detected for more than a predetermined time in relation to the state obtained from the vehicle information, problems may arise that cause an error display on the car navigation system, or cause the navigation operation or viewing of television, etc. to stop. In addition, a warning may be displayed on the vehicle's display.

[0006] Prior art has been disclosed that prevents errors in car navigation systems by controlling the GPS signal when different states, such as "stopped" and "driving," are detected. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 7130294 [Patent Document 2] Patent No. 7274806 [Overview of the project] [Problems that the invention aims to solve]

[0008] Patent Document 2 discloses an adapter that provides a car navigation system (car navigation system) with either or both a vehicle speed pulse signal (driving pulse signal) and a CAN-BUS signal (CAN, etc. signal), and which helps avoid errors that occur when watching television, etc., while driving in a car navigation system or a driver assistance system or fault detection device that works in conjunction with a car navigation system (hereinafter referred to as "car navigation system, etc."). The adapter is configured to detect an abnormality when either or both of the driving pulse signal or the CAN, etc. signal provided to the car navigation system indicate that the vehicle is stopped, but the GPS signal provided to the car navigation system continues to indicate that the vehicle is moving for either a predetermined distance or a predetermined time, whichever is correct. The adapter connected between the vehicle and the car navigation system detects that either or both of the driving pulse signal or CAN signals indicate the vehicle is stopped, but the GPS signal provided to the car navigation system indicates the vehicle is moving. Immediately after this detection, the adapter cuts off the GPS signal at a time when the vehicle has not exceeded a predetermined distance or time, whichever is correct. This temporarily suspends the process by which the car navigation system moves the vehicle's position displayed on the system to its current position using either or both of the driving pulse signal or CAN signals and the GPS signal's position information, thereby resolving the problem of the car navigation system displaying an error or ceasing to operate.

[0009] This will be explained in detail using a diagram. Figure 9 shows the input and output signal waveforms of a device that controls a car navigation system, which is connected between a vehicle and a car navigation system and performs calculation processing to transmit vehicle driving information for a first period (hereinafter referred to as "period T1") and a second period (hereinafter referred to as "period T2") to the T2 period. In period T1, a vehicle stop status signal is transmitted to the car navigation system, and in period T2, vehicle driving information for periods T1 and T2 is transmitted to the car navigation system, thereby enabling simultaneous viewing of television and navigation operation while driving. Figure (a) shows the signal waveform transmitted from the vehicle to the device. Figure (b) shows the signal waveform transmitted from the device to the car navigation system while watching television while driving. Patent Document 2 employs the above signal processing to enable viewing of television while driving.

[0010] Incidentally, some car navigation systems and driver assistance functions installed in recent vehicles use GPS positioning information in addition to vehicle driving information to detect errors or disable functions.

[0011] Figure 10 illustrates a case where a car navigation system uses GPS positioning information in conjunction with vehicle driving information, and an error occurs when the states of the vehicle driving information and the GPS positioning information differ. The lower rectangular frame shows the signal waveform transmitted to the car navigation system by a device that controls the car navigation system, which enables simultaneous viewing of television, etc., and navigation operation while driving. The upper frame outside the frame is an image of the processing in the car navigation system. When the car navigation system detects that the states of "driving" and "stopped" differ between the vehicle driving information and the GPS positioning information, it resets the distance variable and starts counting the distance variable. Subsequently, it periodically acquires GPS positioning information and compares it with the vehicle driving information to determine whether the GPS positioning information and the vehicle driving information indicate the same state of "driving" or "stopped". If they do not continuously indicate the same state, it continues counting the distance variable, and when the distance variable reaches a predetermined distance, it determines that an error has occurred. When an error occurs, the car navigation and driver assistance functions will stop. The car navigation and driver assistance functions will resume when they continuously indicate the same state of "driving" or "stopped". If the vehicle subsequently displays two different states, either "driving" or "stopped," the distance variable is reset again, the counting of the distance variable is restarted, and monitoring continues in the same manner.

[0012] Patent Document 2, as shown in Figure 11, uses a distance variable to prevent the adapter from detecting an error in the car navigation system by blocking the GPS signal before reaching a predetermined distance, thereby preventing the car navigation system from recognizing the error. The lower rectangular frame shows the signal waveform transmitted to the car navigation system by a device that controls the car navigation system, which allows simultaneous viewing of television and navigation operation while driving, while the upper frame outside the frame is an image of the processing in the car navigation system. After blocking the GPS signal for a predetermined time to prevent the car navigation system from making an error, the distance variable is reset again, and the above operation is repeated periodically to continue preventing errors in the car navigation system. In addition, another example discloses a similar avoidance method using a timer instead of a distance variable.

[0013] However, the above method had a problem in that it repeatedly and forcibly cut off the GPS signal before the vehicle reached a predetermined distance or time, regardless of the vehicle information acquired by the vehicle. This reduced the accuracy of the GPS positioning location of the car navigation system, resulting in a large discrepancy between the actual vehicle position and the measured position.

[0014] Recently, there are car navigation systems that perform error monitoring as shown in Figure 12. This illustrates a case where an error occurs when the location information of the vehicle driving information and the GPS positioning information differ, using GPS positioning information in conjunction with other data. The lower rectangular frame shows the signal waveform transmitted to the car navigation system by a device that controls the car navigation system to enable simultaneous viewing of television, etc., and navigation operation while driving, while the upper frame outside the frame is an image of the processing in the car navigation system. When the car navigation system detects that the location information of "driving" and "stopped" differs between the vehicle driving information and the GPS positioning information, it resets the timer and starts counting the elapsed time. Subsequently, it periodically acquires GPS positioning information and compares it with the vehicle driving information to determine whether the GPS positioning information and the vehicle driving information indicate the same state of "driving" or "stopped" and the same location information. If they do not continuously show the same state and location information, it continues counting the elapsed time, and when the elapsed time reaches the upper limit of the third period (hereinafter referred to as "t3 period"), it determines that an error has occurred. The t3 period will be described in detail later. If an error occurs, the car navigation and driver assistance functions will stop. If the same state ("driving" or "stopped") and the same location information are continuously displayed, the car navigation and driver assistance functions will resume. If the same state and location information are not continuously displayed thereafter, the timer will be reset again and the elapsed time count will start again. Furthermore, there are car navigation systems that are configured not to compare vehicle driving information obtained from one or both of the driving pulse signal or CAN signals with GPS positioning information when the speed of the monitored vehicle falls below a predetermined speed. In such car navigation systems, if the adapter of Patent Document 2 is used, the error avoidance operation is forced even though it is unnecessary, as described above. As a result, the GPS vehicle position correction may not be performed correctly in the car navigation system, and the vehicle position held by the car navigation system may deviate from the correct position.

[0015] The present invention has been made in view of the above problems, and among vehicle information, depending on the presence or absence of determination of vehicle position information corresponding to different vehicle speeds that exceed a predetermined threshold value of the vehicle position information obtained from vehicle running information and GPS positioning information, it is an object to provide a car navigation control device that prevents a car navigation or the like from generating an error and enables both viewing of a television or the like and navigation operation.

Means for Solving the Problems

[0016] In order to solve the above problems, the car navigation control device of the present invention is a device that is connected between a vehicle and a car navigation and controls the car navigation, and includes a receiving means for receiving vehicle information transmitted from the vehicle toward the car navigation, an arithmetic means for performing an operation on the vehicle information, a storage means for storing the vehicle information according to an instruction of the arithmetic means, and a transmitting means for transmitting the vehicle information or the vehicle running information after the operation to the car navigation. When a car navigation system determines an error based on a mismatch between vehicle driving information and GPS positioning information, the calculation means includes an error avoidance means that causes the car navigation system to be unable to use GPS positioning information for a predetermined period of time before the mismatch is used for error determination, thereby preventing the car navigation system from recognizing the error. It is characterized by the above.

[0017] Also, the car navigation control device of the present invention The car navigation system is characterized by having an error avoidance means that, when it detects that the vehicle driving information and GPS positioning information are different location information for a third period of time at a predetermined vehicle speed or higher, or when it detects that the vehicle driving information and GPS positioning information are different location information exceeding a predetermined tolerance value for a predetermined time or a predetermined number of times within the third period, the calculation means detects vehicle driving information indicating that the vehicle is stopped despite being in motion, and monitors the elapsed time since detecting that the vehicle speed is above a predetermined speed, and before the elapsed time reaches the third period, the GPS signal is blocked or made unpositionable for a fourth period of time, thereby preventing the car navigation system from recognizing an error.

[0018] Also, the car navigation control device of the present invention The calculation means is characterized in that, when monitoring the elapsed time, if the vehicle speed falls below a predetermined speed, it stops monitoring the elapsed time and returns it to its initial value, and then stops monitoring the elapsed time until the vehicle speed rises to or exceeds the predetermined speed.

[0019] Also, the car navigation control device of the present invention The system is characterized in that, when the GPS antenna fails to acquire the GPS signal from the positioning satellite and positioning becomes impossible, the calculation means stops monitoring the elapsed time, resets the elapsed time to its initial value, and stops monitoring the elapsed time again until the GPS antenna becomes able to perform positioning.

[0020] Also, the car navigation control device of the present invention The calculation means is characterized in that it repeatedly performs the error avoidance means from the start until the transmission means stops transmitting vehicle driving information, which indicates that the vehicle is stopped despite being in motion.

[0021] Furthermore, the car navigation control device of the present invention is characterized in that the receiving means receives some or all of the vehicle driving information transmitted from the vehicle to the car navigation system while the receiving means is permitted to acquire the vehicle driving information by command of the calculation means, the storage means stores the vehicle driving information for the periods that appear in the order of a first period and a second period acquired by the receiving means, the calculation means performs calculations for transmitting the vehicle driving information for the first period and the subsequent second period to the second period and inputs it into the calculated vehicle driving information, and the transmitting means transmits vehicle driving information indicating that the vehicle is stopped in the first period to the car navigation system, and calculated vehicle driving information in the second period.

Effects of the Invention

[0022] According to the car navigation control device of the present invention, even when it is possible to watch TV or the like with the car navigation during driving, the car navigation can operate while avoiding an error caused by the difference in position information between the "vehicle driving information" and the "GPS positioning information" obtained from the vehicle information. Further, it is possible to suppress the unnecessary interruption of the GPS signal or the occurrence of a positioning impossible state when avoiding an error. Furthermore, it is possible to suppress an adverse effect on a driving support system or a failure detection device that cooperates with the car navigation due to the difference in position information between the "vehicle driving information" and the "GPS positioning information".

[0023] Also, according to the car navigation control device of the present invention, it is possible to continue the navigation operation in the background of the car navigation on which a video such as TV is displayed, and to display the correct vehicle position immediately after ending the TV viewing.

[0024] Also, according to the car navigation control device of the present invention, it is possible to obtain the same position accuracy as the vehicle position accuracy of the navigation operation when no video such as TV is displayed, regarding the vehicle position accuracy of the navigation operation continued in the background of the car navigation on which a video such as TV is displayed.

Brief Description of the Drawings

[0025] [Figure 1] It is an example of a system configuration diagram of a vehicle 20 when a car navigation control device 10 according to the present invention is in use. [Figure 2] It is an example of a block diagram of a related part of a car navigation control device 10 and a vehicle 20 according to the present invention. [Figure 3] It is an example of signal processing in a car navigation control device 10 that enables both TV viewing and navigation operation while avoiding an error caused by the accumulation of the difference in position information between vehicle driving information and GPS positioning information. [Figure 4] It is a diagram showing an example of a method for controlling a GPS signal when avoiding an error. [Figure 5]This is an example of a flowchart for a car navigation control device 10 that avoids errors caused by the accumulation of discrepancies between vehicle driving information and GPS positioning information. [Figure 6] This is another example of a flowchart in a car navigation control device 10 that avoids errors caused by the accumulation of discrepancies between vehicle driving information and GPS positioning information. [Figure 7] This is another example of signal processing in a car navigation control device 10 that enables simultaneous viewing of television and navigation operation while avoiding errors caused by the accumulation of discrepancies between vehicle driving information and GPS positioning information. [Figure 8] This is an embodiment of the input signal pattern for vehicle driving information from the vehicle 20 and the output signal pattern for vehicle driving information to the car navigation system 30 when using the car navigation control device 10 according to the present invention connected to the car navigation system 30. [Figure 9] This shows a conventional example of input / output signal waveforms of a device that controls a car navigation system 30, which is connected between the vehicle 20 and the car navigation system 30, enabling simultaneous viewing of television and other media and navigation operation while the vehicle is in motion. [Figure 10] Figure 9 illustrates a case where an error occurs when transmitting the signal waveform shown to the car navigation system 30 due to the accumulation of discrepancies between the vehicle driving information and the GPS positioning information. [Figure 11] This diagram illustrates a conventional method for avoiding errors. [Figure 12] This figure illustrates an error that occurs when the method shown in Figure 11 is applied to a car navigation system 30 that is configured not to compare vehicle driving information obtained from one or both of the driving pulse signal or the CAN signal SG with GPS positioning information when the vehicle speed 20 falls below a predetermined speed. [Modes for carrying out the invention]

[0026] Embodiments for implementing the car navigation control device 10 according to the present invention will be described with reference to the figures. Figure 1 is an example of a system configuration diagram of a vehicle 20 when using the car navigation control device 10 according to the present invention. The vehicle 20 is equipped with a common bidirectional data bus line, such as a CAN bus line 50, to which sensors and control devices necessary for the safety and automation of the vehicle 20 are connected, and various signals are input and output. In Figure 1, sensors such as a front camera 60, a rear camera 62, an illuminance sensor 64, a front sonar 66, a back sonar 68, a vehicle speed sensor (not shown), and an acceleration sensor (not shown) are connected. In addition, a Global Navigation Satellite System (GNSS) is used to determine the vehicle's position. Generally, this is often called the Global Positioning System (GPS). The GPS positioning control unit 40, to which a GPS antenna 40 (in this specification, "GNSS antenna" and "GPS antenna" are collectively referred to as "GPS antenna") is connected, is connected to the car navigation system 30. Signals from various sensors are processed by the vehicle electronic control unit 22 and transmitted (output) as vehicle information to safety devices, automation devices, and the car navigation system 30. Information feedback is also received (input) from the safety devices, automation devices, and the car navigation system 30 as needed.

[0027] The car navigation control device 10 is an adapter-type device connected between the vehicle electronic control unit 22 and the car navigation system 30, and controls the car navigation system 30. The vehicle electronic control unit 22 is an ECU (El This is called an electronic control unit. Normally, the car navigation system 30 is set so that video viewing using a television, etc., is not possible while the vehicle 20 is in motion. However, since passengers in the front or rear seats may want to watch videos while the vehicle 20 is in motion, the car navigation control device 10 is connected to the signal line that transmits vehicle information from the vehicle electronic control unit 22 to the car navigation system 30, making it possible to watch television, etc., even while the vehicle is in motion. The car navigation control device 10 is also connected to the GPS signal control unit 40 and controls GPS signal input / output or GPS signal processing.

[0028] Figure 2 is a block diagram of the relevant parts of the car navigation control device 10 and vehicle 20 according to the present invention.

[0029] The car navigation control device 10 includes a calculation unit 12 as a calculation means for performing calculations on vehicle information, a storage unit 14 as a storage means for storing vehicle information according to the instructions of the calculation unit 12, and a transmitting / receiving unit 16 which also serves as a receiving means for receiving vehicle information SG1 transmitted from the vehicle 20 to the car navigation system 30 and a transmitting means for transmitting calculated vehicle driving information SG2 obtained by the calculation unit 12 or unprocessed vehicle information SG2 received from the vehicle to the car navigation system 30. The calculation unit 12 is equipped with a timer for time control and also controls the other units. The units are connected by a bus line 18 for information exchange. The bus line 18 is also connected to the GPS signal control unit.

[0030] The GPS control unit 11 may be attached to the car navigation control unit 10 as a GPS control device, or it may be installed inside the car navigation control unit 10 and inserted into the GPS signal line using a connector. The GPS control unit 11, based on commands from the calculation unit 12 to the GPS signal processing unit 110, allows or blocks the GPS signal or causes the car navigation system 30 to enter a positioning failure state.

[0031] First, the basic operation of the car navigation control device 10 according to the present invention will be described. Figure 3 shows an example of signal processing in the car navigation control device 10 that enables simultaneous viewing of television and navigation operation while avoiding errors caused by the accumulation of discrepancies between vehicle driving information and GPS positioning information.

[0032] The example of error detection by the car navigation system 30 shown in the upper part of the square frame in Figure 3 is as follows: When the vehicle speed is V1 or higher, the system detects that the vehicle driving information and the GPS positioning information are different location information. The system starts measuring a timer variable (TC) provided in the car navigation system 30, and determines that an error has occurred when the accumulation of different location information between the vehicle driving information and the GPS positioning information for a continuous period of t3 exceeds a predetermined threshold. If the vehicle speed falls below V1 before the upper limit of the t3 period is reached, the car navigation system 30 stops comparing the vehicle driving information and the GPS positioning information and resets the timer variable (TC). When the vehicle speed becomes V1 or higher again, the measurement of the timer variable (TC) is resumed. Subsequently, if the discrepancy between the location information of the vehicle driving information and the GPS positioning information continues to accumulate and exceeds a predetermined threshold, or if a state occurs where accurate location information cannot be obtained continuously, an error occurs when the timer variable (TC) reaches the upper limit of the t3 period.

[0033] Another example of error detection by the car navigation system 30 is when a discrepancy in location information between vehicle driving information and GPS positioning information is detected more than a predetermined number of times within the t3 period. In this case as well, when the vehicle speed falls below V1, the comparison between vehicle driving information and GPS positioning information is stopped and the timer variable (TC) is reset. When the vehicle speed rises to V1 or higher again, measurement of the timer variable (TC) is resumed. Subsequently, when the timer variable (TC) reaches the upper limit of the t3 period, an error occurs if a discrepancy in location information between vehicle driving information and GPS positioning information is detected more than a predetermined number of times.

[0034] The car navigation control device 10, upon starting to acquire vehicle driving information, monitors that the vehicle speed is V1 or greater, starts counting the timer variable TC1 in the timer provided in the calculation unit 12, and confirms that TC1 has not reached the upper limit of the t3 period. That is, it sets a threshold t3' (hereinafter referred to as "t3' time") which is less than the upper limit of the t3 period, and determines whether TC1 has reached t3' time or not. At the same time, if the vehicle speed falls below V1 during the t3 period, it resets TC1 and initializes the timer. Subsequently, when the vehicle speed becomes V1 or greater, it starts counting TC1, and when TC1 reaches t3' time, it blocks or disables the GPS signal for a fourth period (hereinafter referred to as "t4 period") to prevent the car navigation system 30 from recognizing an error. Therefore, this system can be adapted to avoid errors when it detects that the vehicle driving information and GPS positioning information have accumulated different location information for a continuous period of t3, or when it detects a position information discrepancy exceeding a predetermined tolerance value between the vehicle driving information and GPS positioning information more than a predetermined number of times within period t3. The above example of an error is one caused by the vehicle 20 transmitting a signal indicating that it is stopped while in motion in order to watch television, etc., but it is also possible to avoid similar errors caused by other factors. The method for avoiding the error that occurs when watching television, etc., while in motion, which is a typical example of this error, will be described in detail later.

[0035] The following describes an embodiment applicable when GPS positioning information is acquired by the car navigation control device 10, and the GPS signal is interrupted or positioning becomes impossible due to external factors.

[0036] In the car navigation system 30, when the GPS signal is interrupted or becomes unpositionable due to external factors, the timer variable (TC) is reset, and the t3 period is started to be measured when positioning becomes possible again using the GPS signal and the position information of the vehicle driving information and the GPS positioning information differ. By acquiring GPS positioning information with the car navigation control device 10 and determining whether or not positioning information has been achieved, the timing of the timer reset in the car navigation system 30 can be controlled, and by simultaneously resetting the timer variable (TC1) of the car navigation control device 10, it becomes possible to synchronize with the error detection timing of the car navigation system 30. Compared to not acquiring GPS positioning information, it may be possible to reduce the number of times the car navigation control device 10 forcibly interrupts the GPS signal or makes it unpositionable during the t4 period. Reducing the number of times the car navigation control device 10 forcibly interrupts the GPS signal or makes it unpositionable has the effect of suppressing the deviation of the vehicle display position in the car navigation system 30.

[0037] The following describes how to control the GPS signal. A simple method involves inserting a relay contact in the GPS signal line from the GPS antenna 40 to the car navigation system 30 and selecting, based on a command from the calculation unit 12, to pass the GPS received signal SG3 as the GPS output signal SG4 or to block the GPS received signal SG3. However, various methods can be used, so several examples will be described.

[0038] Figure 4 shows five examples of methods for controlling GPS signals to avoid errors. Figure 4(a) shows a method in which a GPS control unit 11 is installed in the GPS signal line from the GPS antenna 40 to the car navigation system 30, a semiconductor is inserted into the GPS signal processing unit a111, and gain control is performed to attenuate the output of the semiconductor, thereby disabling positioning using the GPS signal. Gain control can also be performed to amplify the output of the semiconductor. This method allows the system to select whether positioning using the GPS signal is possible or impossible based on a command from the calculation unit 12.

[0039] Figure 4(b) shows a method in which a GPS control unit 11 is installed in the middle of the GPS signal line from the GPS antenna 40 to the car navigation system 30, and the power supply to the GPS antenna 40 is controlled by the GPS signal processing unit b112. This method involves inserting a device that can electrically energize or disconnect a circuit, such as a relay contact or semiconductor switch (hereinafter referred to as "relay or other switch"), into the power line supplied to the GPS signal line, and turning the relay or other switch OFF by a command from the calculation unit 12, thereby cutting off the power supply to the GPS antenna 40.

[0040] Figure 4(c) shows a method in which a dummy GPS antenna 440 is mounted in addition to the regular GPS antenna 40, and the GPS signal processing unit c113 provided in the GPS control unit 11 switches between the regular GPS antenna 40 and the dummy GPS antenna 440 to shift the GPS positioning information and control whether positioning is possible, impossible, or the positioning accuracy is reduced.

[0041] Figure 4(d) shows a method in which an antenna 442 that interferes with the reception of GPS signals is mounted near the regular GPS antenna 40, and the GPS signal processing unit d114 provided in the GPS control unit 11 controls the blocking or passing of GPS signals by turning the GPS signal interference antenna ON or OFF.

[0042] Figure 4(e) shows a method in which the GPS antenna 40 is housed in a shield case, the GPS antenna 40 is either retracted or opened, or a radio wave shielding plate facing upwards is placed at the GPS signal incidence position above the GPS antenna 40, and the GPS signal processing unit e115 provided in the GPS control unit 11 controls the shielding or passage of the GPS signal, thereby enabling or disabling positioning using GPS positioning information.

[0043] The above describes five examples, but the method is not limited to these; any well-known method that allows for the selection of whether to pass or block GPS signals, or whether to enable or disable GPS positioning information, is acceptable.

[0044] Figure 5 is an example of a flowchart in the car navigation control device 10 that avoids errors caused by the accumulation of discrepancies between vehicle driving information and GPS positioning information. Figure 5 is an example of a flowchart in the car navigation control device 10 when GPS positioning information is not monitored.

[0045] The program according to the present invention first enables interrupts for acquiring vehicle driving information and measuring the elapsed time timer (S102) immediately after starting the main processing (hereinafter referred to as the "main routine") (step 101 (hereinafter, "step" will be replaced with "S")). By enabling the interrupt for acquiring vehicle driving information, an interrupt processing routine (I101~I104) becomes executable, which sums up and saves the number of pulses each time it detects vehicle driving information transmitted from the vehicle 20, such as a driving pulse signal. In the explanation of Figure 5, vehicle driving information is exemplified as a driving pulse signal, but the vehicle driving information may also be vehicle speed data obtained from a CAN-BUS or the like, instead of a driving pulse signal. Here, the pulse period of the driving pulse signal represents the time it takes to travel a predetermined distance. Therefore, a shorter pulse width indicates a faster speed, and a longer pulse width indicates a slower speed.

[0046] In the case of a domestically produced car, vehicle 20 travels approximately 0.42m in one pulse. If the pulse width is 0.1sec, then vehicle 20 will travel approximately 15.12km per hour. That is, a speed of 15.12km / h.

[0047] Specifically, the interrupt processing routine for acquiring vehicle driving information starts processing (I101) when it detects one driving pulse signal from vehicle 20. Detection of one driving pulse signal may also occur when the signal potential changes. The same applies hereafter. Regardless of the flow or state of the main routine, the driving pulse signal is always acquired when it is transmitted from vehicle 20. When one pulse is detected, the result of adding the pulse count PM in the storage memory (PM = PM + 1) is saved (I102). The variable PM can be used when watching TV or other devices while driving. An example of this will be described later. Next, the pulse interval acquired this time is calculated from the previously acquired pulse and the current vehicle speed is acquired (I103). With this, the interrupt processing ends and the program returns to the step of the main routine that was being processed immediately before executing the interrupt processing routine (I104).

[0048] Furthermore, by enabling the elapsed time timer interrupt, interrupt handling routines (I201~I203) can be executed, which increment and save the timer variable TC1 each time a predetermined time has elapsed. For example, the predetermined time may be 0.1 seconds.

[0049] Specifically, the elapsed time timer interrupt processing routine starts processing (I201) when an interrupt occurs from the elapsed time timer of the arithmetic unit 12. Regardless of the flow or state of the main routine, the elapsed time timer interrupt processing routine is always processed when a timer interrupt occurs. Upon detecting an interrupt, the result of adding the timer variable TC1 (TC1 = TC1 + 1) is saved (I202), the interrupt processing ends, and the program returns to the main routine step that was being processed immediately before executing the interrupt processing routine (I203).

[0050] As mentioned above, when driving at a predetermined speed (V1) or higher, and the car navigation control device 10 is set to TV viewing mode, an error occurs if the vehicle driving information and GPS positioning information are determined to be different location information for a continuous period of t3, or if accurate location information cannot be obtained continuously. Therefore, the main routine processes as follows: After enabling interrupts for vehicle driving information acquisition and elapsed time timer measurement (S102), the timer variable TC1, which is measuring the elapsed time, is reset (TC1=0) (S103).

[0051] The car navigation control unit 10 determines whether or not the TV viewing mode is being maintained. If the TV viewing mode is being maintained, error monitoring must be continued because there is a possibility that the position information between the vehicle driving information and the GPS positioning information may become misaligned and accumulate, so the process in S105 is performed (S104).

[0052] In S105, it is determined whether the vehicle speed of vehicle 20 is V1 or greater. If the vehicle speed obtained in the interrupt processing routine I103 for acquiring vehicle driving information is less than V1, the vehicle driving information obtained from one or both of the driving pulse signal or the signal SG such as CAN is not compared with the GPS positioning information, and the timer variable TC of the car navigation system 30 is reset. Therefore, the car navigation control device 10 also returns to S103 and resets TC1. If it is determined that the vehicle speed of vehicle 20 is V1 or greater, error monitoring must continue, so the process in S106 is performed.

[0053] In S106, it is determined whether TC1 has reached time t3'. If it is determined that time t3' has not been reached, the process returns to S104 in order to continue error monitoring. If it is determined that time t3' has been reached, the error avoidance process (S107) is executed. Time t3' is a period less than t3, based on the t3 period, that accounts for the time accuracy error due to the non-uniform processing time of the car navigation system 30 or the car navigation control device 10 program and individual hardware differences.

[0054] Error avoidance is performed by blocking the GPS signal or making it impossible to position for a period of t4, as illustrated in Figure 4 (step S107). When the GPS signal is blocked or made impossible to position for a period of t4, the car navigation system 30 does not compare the vehicle driving information obtained from one or both of the driving pulse signal or the signal SG such as CAN with the GPS positioning information. As a result, the timer variable TC of the car navigation system 30 is reset, and it is not recognized as an error, thus avoiding the error. The t4 period is set to be longer than the t5 period, during which the car navigation system 30 does not perform error processing and resets the timer variable (TC) due to the GPS signal being blocked or making it impossible to position. A detailed explanation of the t5 period will be given later, but it is preferable that the t4 period is the same as the t5 period or slightly longer. This is because the car navigation system 30 can reliably reset the timer variable TC and synchronize the timer variable TC with the timer variable TC1 of the car navigation control device 10. After avoiding the error, the process returns to S103, and while the car navigation control unit 10 is running TV viewing mode, the processes from S103 to S107 are repeated.

[0055] Figure 6 is another example of a flowchart in the car navigation control device 10 that avoids errors caused by the accumulation of discrepancies between vehicle driving information and GPS positioning information. Figure 6 is an example of a flowchart when the car navigation control device 10 monitors GPS positioning information. When monitoring GPS positioning information, the car navigation system 30 needs to be directly connected to the CAN or other bus line 50, as shown by the dashed lines in Figures 1 and 2. The car navigation control device 10 also includes a CAN or other receiving unit 17 that receives vehicle information from the CAN or other bus line 50, and needs to be directly connected to the CAN or other bus line 50, as shown by the dashed lines in Figures 1 and 2.

[0056] The program shown in Figure 6, immediately after starting the main routine (S201), first enables interrupts for acquiring vehicle driving information, acquiring GPS positioning information, and measuring the elapsed time timer (S102). By enabling the interrupt for acquiring vehicle driving information, the interrupt processing routines (I301~I304) that sum up and save the number of pulses each time they detect vehicle driving information transmitted from vehicle 20, such as a driving pulse signal, become executable. In the explanation of Figure 6, vehicle driving information is exemplified as a driving pulse signal, but the vehicle driving information may also be vehicle speed data obtained from CAN-BUS, etc., instead of a driving pulse signal. Here, the pulse period of the driving pulse signal represents the time it takes to travel a predetermined distance, as in the explanation of Figure 5. Therefore, a shorter pulse width indicates a faster speed, and a longer pulse width indicates a slower speed.

[0057] Specifically, the interrupt processing routine for acquiring vehicle driving information starts the interrupt processing (I301) when it detects one driving pulse signal from vehicle 20. Regardless of the flow or state of the main routine, it always acquires the driving pulse signal when it is transmitted from vehicle 20. When one pulse is detected, the result of adding the pulse count PM in the storage memory (PM = PM + 1) is saved (I302). The variable PM can be used when watching TV or other devices while driving. An example of this will be described later. Next, the pulse interval acquired this time is calculated from the previously acquired pulse and the current vehicle speed is acquired (I303). With this, the interrupt processing ends and the program returns to the step of the main routine that was being processed immediately before executing the interrupt processing routine (I104).

[0058] By enabling the GPS positioning information acquisition interrupt routine, GPS positioning information can be acquired from the vehicle 20 at the time of GPS positioning, and the interrupt processing routines (I501~I503) that set the GPS acquisition flag can be executed. GPS positioning information includes location information obtained by acquiring GPS signals and performing GPS positioning (GPS positioning information), and information obtained when the GPS signal is significantly attenuated and cannot be acquired due to factors such as GPS radio waves being blocked in tunnels, or when positioning is impossible (hereinafter referred to as "GPS positioning failure information").

[0059] Specifically, the GPS positioning information acquisition interrupt routine starts interrupt processing (I501) when it receives GPS positioning information. Regardless of the flow or state of the main routine, GPS positioning information is always acquired via the CAN or other receiving unit 17 when transmitted from the vehicle 20. When GPS positioning information is acquired, the GPS acquisition flag GP in the storage memory is set to "1" (GP=1), and when GPS positioning failure information is acquired, the GPS acquisition flag GP in the storage memory is set to "0" (GP=0), and the information is saved (I502). Once the acquisition of GPS positioning information or GPS positioning failure information is complete, the interrupt processing ends, and the program returns to the main routine step that was being processed immediately before executing the interrupt processing routine (I503).

[0060] Furthermore, by enabling the elapsed time timer interrupt, interrupt handling routines (I401~I403) can be executed, which increment and save the timer variable TC1 each time a predetermined time has elapsed. For example, the predetermined time may be 0.1 seconds.

[0061] Specifically, the elapsed time timer interrupt processing routine starts processing (I401) when an interrupt occurs from the elapsed time timer of the arithmetic unit 12. Regardless of the flow or state of the main routine, the elapsed time timer interrupt processing routine is always processed when a timer interrupt occurs. Upon detecting an interrupt, the result of adding the timer variable TC1 (TC1 = TC1 + 1) is saved (I402), the interrupt processing ends, and the program returns to the main routine step that was being processed immediately before executing the interrupt processing routine (I403).

[0062] As mentioned above, when driving at a predetermined speed (V1) or higher, and the car navigation control device 10 is set to TV viewing mode, an error occurs if the vehicle driving information and GPS positioning information are determined to be different location information for a continuous period of t3, or if accurate location information cannot be obtained continuously. Therefore, the main routine processes as follows: After enabling interrupts for acquiring vehicle driving information, acquiring GPS positioning information, and measuring the elapsed time timer (S202), the timer variable TC1, which is measuring the elapsed time, is reset (TC1=0) (S203).

[0063] The car navigation control unit 10 determines whether or not the TV viewing mode is being maintained. If the TV viewing mode is being maintained, error monitoring must be continued because there is a possibility that the position information between the vehicle driving information and the GPS positioning information may become misaligned and accumulate, so the process in S205 is performed (S204).

[0064] In S205, it is determined whether the vehicle speed of vehicle 20 is V1 or greater. If the vehicle speed obtained in the interrupt processing routine I303 for acquiring vehicle driving information is less than V1, the vehicle driving information obtained from one or both of the driving pulse signal or the signal SG such as CAN is not compared with the GPS positioning information, and the timer variable TC of the car navigation system 30 is reset. Therefore, the car navigation control device 10 also returns to S203 and resets TC1. If it is determined that the vehicle speed of vehicle 20 is V1 or greater, error monitoring must continue, so the process in S206 is performed.

[0065] In S206, it is determined whether the GPS signal has been interrupted or is unable to acquire a position for the duration of t5. When the car navigation system 30 detects that the GPS signal has been interrupted or is unable to acquire a position, it does not compare the vehicle driving information obtained from one or both of the driving pulse signal or the signal SG such as CAN with the GPS positioning information. If it is determined that the state in which this comparison is not performed continues beyond the duration of t5, the timer variable TC of the car navigation system 30 is reset. The duration of t5 is the period during which the car navigation system 30 does not perform error processing due to the GPS signal being interrupted or unable to acquire a position, and the timer variable (TC) is reset when this period is reached. Normally, the duration of t5 is used for processing to avoid the system recognizing an error when the vehicle 20 enters a tunnel or a canyon between tall buildings. Therefore, the car navigation control device 10 also returns to S203 and resets TC1. If it is determined that GPS positioning information can be acquired and positioning is possible, it is necessary to continue error monitoring, so the processing in S207 is performed.

[0066] In S207, it is determined whether TC1 has reached time t3'. If it is determined that time t3' has not been reached, the process returns to S204 in order to continue error monitoring. If it is determined that time t3' has been reached, the error avoidance process (S208) is executed. Time t3' is a period less than t3, based on the t3 period, that accounts for the time accuracy error due to the non-uniform processing time of the car navigation system 30 or the car navigation control device 10 program and individual hardware differences.

[0067] Error avoidance is performed by blocking the GPS signal or making it impossible to position for a period of t4, as illustrated in Figure 4 (S208). When the GPS signal is blocked or made impossible to position for a period of t4, the car navigation system 30 does not compare the vehicle driving information obtained from one or both of the driving pulse signal or the signal SG such as CAN with the GPS positioning information. As a result, the timer variable TC of the car navigation system 30 is reset, and it is not recognized as an error, thus avoiding the error. The t4 period is set to be longer than the t5 period, during which the car navigation system 30 does not perform error processing and resets the timer variable (TC) due to the GPS signal being blocked or making it impossible to position. More specifically, it is preferable that the t4 period is the same as the t5 period or slightly longer. This is because the car navigation system 30 can reliably reset the timer variable TC and synchronize the timer variable TC with the timer variable TC1 of the car navigation control device 10. After the error occurring in the car navigation system 30 is avoided by the processing in S208 of the car navigation control device 10, the process returns to S203, and the car navigation control device 10 repeats the processes from S203 to S207 while the TV viewing mode is running.

[0068] Figure 7 shows another example of signal processing in a car navigation control device 10 that enables simultaneous viewing of television and navigation operation while avoiding errors caused by the accumulation of discrepancies between vehicle driving information and GPS positioning information. There is a car navigation system 30 that changes the t3 period according to the vehicle speed. When the vehicle speed is high, it travels a long distance in a short time, so if the t3 period is not shortened and error processing is not performed, the vehicle position deviation in the car navigation system 30 will become large. Accordingly, the t3' and t4 periods set in the car navigation control device 10 also need to be shortened. The t3' period must be shorter than the t3 period. The reason for shortening the t4 period is the same as in the case of the t3 period: if the GPS signal is blocked or positioning is impossible for a long time when the vehicle 20 is traveling at high speed, the vehicle position deviation in the car navigation system 30 will become large. To address the above case, the car navigation control device 10 creates a table that changes the t3' period according to the speed, and by referring to the speed as needed and changing the t3' period, it is possible to suppress the position deviation of the vehicle 20 in the car navigation system 30. [Examples]

[0069] The embodiment described above can be applied to the process of enabling simultaneous viewing of television and other devices and navigation operation in the car navigation control device 10 while the vehicle is in motion. Below, an example of a specific method for enabling simultaneous viewing of television and other devices and navigation operation will be described. Figure 8 shows one embodiment of the input signal pattern of vehicle driving information from the vehicle 20 and the output signal pattern of vehicle driving information to the car navigation 30 when using the car navigation control device 10 according to the present invention connected to the car navigation 30.

[0070] When the car navigation control device 10 performs processing to enable simultaneous viewing of television and other devices and navigation operation while the vehicle is in motion, the storage unit 14 stores vehicle driving information for periods that appear in the order of T1 period and T2 period, as long as it is permitted to acquire vehicle driving information by command of the calculation unit 12. It is highly preferable from the viewpoint of accurately indicating the vehicle's position to store all vehicle driving information transmitted from the vehicle 20. However, when acquiring or saving vehicle driving information, the storage unit 14 may reduce its burden by storing vehicle driving information that has been "data compressed," which involves thinning out data to a practically acceptable extent during the calculation of vehicle driving information performed by the calculation unit 12. The "data compression" referred to here when acquiring or saving vehicle driving information means reducing the total amount of data by utilizing the redundancy, regularity, and unnecessary properties of the original data. This is different from the method by which the calculation unit 12 compresses the pulse width of the driving pulse signal in the time axis direction in order to transmit the calculated vehicle driving information to the car navigation 30 during period T2. When acquiring or saving vehicle driving information, "data compression" can be either "lossless compression," which completely restores the original data through "decompression" (also called unzipping or extraction), or "lossy compression" (also called irreversible compression), which allows for some data loss when "decompression" is performed. Since the speed fluctuations of vehicle 20 over a period of about one second are minor unless sudden driving operations are performed, there is no practical problem in using either "lossless compression" or "lossy compression." If you want to achieve greater accuracy while using "lossy compression" for "data compression" when acquiring or saving vehicle driving information, it is advisable to use "lossless compression" when vehicle 20 is accelerating or decelerating, and "lossy compression" when vehicle 20 is traveling at a constant speed or when acceleration or deceleration is gradual. This is because it improves efficiency and allows for a restoration closer to the original data compared to using "lossy compression" alone.

[0071] The calculation unit 12 performs calculations to transmit vehicle driving information for period T1 and the following period T2 to period T2, and inputs the calculated vehicle driving information into the calculation unit. If "data compression" is performed when acquiring or saving vehicle driving information, it performs "decompression processing" before performing calculations and inputs the calculated vehicle driving information into the calculation unit.

[0072] During period T1, the transmitting / receiving unit 16 transmits a vehicle stop status signal from the vehicle 20 to the car navigation system 30, and during period T2, it transmits calculated vehicle driving information to the car navigation system 30.

[0073] By the method described above, the car navigation control device 10 according to the present invention can simultaneously allow viewing of television and other devices and navigation operation while driving.

[0074] The car navigation control device 10 and GPS control unit 11 according to the present invention avoid errors that occur when the conventional method shown in Figure 12 is applied to a car navigation system 30 that is set not to compare vehicle driving information obtained from one or both of the driving pulse signal or the signal SG such as CAN with GPS positioning information when the speed of the vehicle 20 falls below V1 in kilometers per hour. The method will be described below.

[0075] This section details the error avoidance method used in Figure 3 for simultaneously viewing television and operating the navigation system. Figure 3 shows an example of signal processing in the car navigation control device 10 that enables simultaneous viewing of television and navigation operation while avoiding errors caused by the accumulation of discrepancies between vehicle driving information and GPS positioning information. The lower rectangular frame shows the signal waveform transmitted by the car navigation control device 10 according to the present invention to the car navigation system 30, and the upper outside frame is an image of the processing in the car navigation system 30.

[0076] When the car navigation control device 10 transmits vehicle driving information as a "stopped" signal to the car navigation system 30 in order to enable viewing of television, etc., the car navigation system 30 detects that the location information of the vehicle driving information and the GPS positioning information are different. Upon detecting the difference, the car navigation system 30 resets the timer (TC) and starts counting the t3 period. Subsequently, it periodically acquires GPS positioning information and compares it with the vehicle driving information to determine whether the GPS positioning information and the vehicle driving information indicate the same location. If the discrepancy in location information continues to accumulate or accurate location information cannot be obtained continuously, it continues counting the elapsed time (TC), and in principle determines that an error has occurred when the elapsed time reaches the t3 period. However, if the vehicle speed 20 falls below V1 km / h, and the system is set not to compare the vehicle driving information obtained from one or both of the driving pulse signal or the CAN signal SG with the GPS positioning information, the following error avoidance method is applied.

[0077] When the car navigation control device 10 starts watching TV or the like while driving, the vehicle 20 starts sending a vehicle stop status signal to the car navigation system 30, and at that timing, the device resets the timer variable (TC1) built into the calculation unit 12 (TC1=0). On the other hand, when the car navigation system 30 detects that the location information between the vehicle driving information and the GPS positioning information is different, it resets the timer variable (TC) (TC=0). Therefore, TC1 and TC are synchronized. Subsequently, if the same location information is not continuously shown or if accurate location information cannot be continuously obtained, the count of the variable TC1 continues. During this time, when the vehicle speed falls below V1, the car navigation system 30 resets the variable TC (TC=0), so the timer variable TC1 of the car navigation control device 10 is also reset (TC1=0), and the count of TC1 is stopped until the vehicle speed becomes V1 or higher.

[0078] When TC1 reaches time t3', the car navigation control device 10 blocks the GPS signal or puts the GPS positioning into a non-acquisition state, preventing the comparison between vehicle driving information and GPS positioning information. As a result, the timer variable TC of the car navigation system 30 is reset, and it is not recognized as an error. By blocking the GPS signal or creating a non-acquisition state, the car navigation control device 10 synchronously resets the timer variable (TC1) built into the calculation unit 12 of the car navigation control device 10 and the timer variable (TC) of the car navigation system 30 (TC=0 and TC1=0), completing the preparation for avoidance processing for the next error. After period t4 has elapsed and the GPS signal can be acquired, the reset timer variable TC of the car navigation system 30 and the timer variable TC1 of the car navigation control device 10 start counting. Therefore, it is possible to avoid both errors that occur when the car navigation system 30 detects that the vehicle driving information and GPS positioning information are different location information for a continuous period of t3, or when accurate location information cannot be obtained continuously, and errors that occur when the system detects a discrepancy in the vehicle's 20 location information that exceeds a preset tolerance value more than a predetermined number of times within the t3 period. [Examples]

[0079] The car navigation control device 10 according to the present invention can enable simultaneous viewing of television and other devices and navigation operation while driving, and minimize the error between the displayed position of the vehicle 20 on the car navigation system 30 and the actual vehicle position, by employing the following method. One example is described in detail below.

[0080] An example of using a driving pulse signal as vehicle driving information is given. Figure 8 shows an embodiment of the driving pulse signal pattern when the car navigation control device 10 according to the present invention enables viewing of television, etc., while the vehicle is in motion. Figure (a) shows the driving pulse signal transmitted from the vehicle electronic control unit 22. Figure (b) shows the driving pulse signal transmitted by the car navigation control device 10 to the car navigation system 30.

[0081] Periods T1 and T2 are periods set to appear consecutively in the order of Period T1, Period T2, Period T1, and Period T2 after the start of watching television or other devices. Let the arbitrary first period be "T1(n)" and the arbitrary second period be "T2(n)".

[0082] In Figure 8, before starting to watch television or the like, the transceiver 16 is instructed to transmit the driving pulse signal directly to the car navigation system 30 without performing any calculations on the calculation unit 12.

[0083] When a passenger starts watching television or the like, the calculation unit 12 stores the driving pulse signals for period T1 in the storage unit 14 without transmitting them to the car navigation system 30. While the driving pulse signals are stored in the storage unit 14, the calculation unit 12 instructs the car navigation system 30 to transmit a steady-state signal (usually a constant voltage) indicating a "stopped state" or a driving pulse signal longer than a predetermined pulse width (less than a predetermined speed) that the car navigation system 30 recognizes as being in a "stopped state" (referred to as a "vehicle stopped state signal" in this specification). The above is an example of a signal indicating that the vehicle 20 is in a "stopped state".

[0084] Here, the T1 period is set to be longer than the time it takes for the car navigation system 30 to recognize that the vehicle is stopped after receiving a vehicle stop signal when watching television, etc. More specifically, even if the car navigation system 30 receives a vehicle stop signal, it does not immediately start the television or other video. Instead, it continues to confirm that the vehicle 20 is stopped for a predetermined period of time before starting the television or other video. This predetermined time (hereinafter referred to as the "stop judgment time") is set to prevent the car navigation system 30 from overreacting and frequently switching displays. Therefore, by setting the T1 period to be longer than the stop judgment time and transmitting a stop signal to the car navigation system 30 for a time exceeding the stop judgment time, it is possible to start the television or other video even while the vehicle 20 is in motion. In some models of car navigation systems 30 equipped in domestic cars, the stop judgment time is set to 1.5 seconds. Therefore, the T1 period setting of the car navigation control device 10 is longer than the aforementioned 1.5 seconds, and the specific number of seconds for the T1 period varies depending on the type of car navigation system 30.

[0085] When an arbitrary T1(n) period has elapsed, the calculation unit 12 moves the pulse count PM accumulated in the storage memory during the T1(n) period up to that point to the pulse count PM1 in the transmission memory, and calculates the pulse count PMa that is expected to be received during the sum of the T1(n) and T2(n) periods. Subsequently, it calculates the signal format that the pulse count PMa can transmit within the T2(n) period, i.e., the pulse width tp(n).

[0086] In the T2(n) period following the T1(n) period, the calculation unit 12 first calculates the driving pulse signal for the T1(n) period immediately preceding the T2(n) period to a pulse width tp(n) so that it can be transmitted to the car navigation system 30, and inputs the calculated vehicle driving information into the calculation unit. After that, the transmission / reception unit 16 transmits the information to the car navigation system 30.

[0087] Immediately after confirming that all pulse counts PM1 accumulated in the storage memory and moved to the transmission memory during the preceding T1(n) period have been transmitted, if there are driving pulse signals accumulated in the storage memory (pulse count PM > 0), the calculation unit 12 calculates the pulse width tp(n) of the driving pulse signals and inputs the calculated vehicle driving information. At the same time, it subtracts the same number of pulses from the pulse count PM in the storage memory. After that, the transmission / reception unit 16 transmits to the car navigation system 30.

[0088] If the calculation unit 12 determines that there are no driving pulse signals stored in the storage memory (number of pulses PM=0), or if the number of pulses transmitted to the car navigation system 30 during period T2(n) reaches the number of pulses PMa expected to be received during periods T1(n) and T2(n), the calculation of driving pulse signals and the transmission command to the car navigation system 30 to the transmission / reception unit 16 are not performed, and the system proceeds to the next period T1(n+1).

[0089] The T2 period is set to be shorter than the time it takes for the car navigation system 30 to determine that the vehicle 20 is in motion when watching television, etc. More specifically, even if the car navigation system 30 receives a driving pulse signal, it does not immediately stop the television, etc. image. Instead, it stops the television, etc. image only if it continues to receive the driving pulse signal after a predetermined time has elapsed. This prevents the car navigation system 30 from overreacting and causing the display to switch frequently. A set time (hereinafter referred to as the "driving judgment time") exists for this purpose. Therefore, by setting the T2 period to be shorter than the driving judgment time and transmitting the driving pulse signals from the preceding T1 period and the T2 period to the car navigation system 30 during the T2 period, it is possible to continue watching television, etc. without stopping the image, and to provide accurate guidance without stopping the navigation operation and without errors. In some models of car navigation systems 30 equipped in domestic cars, the driving judgment time is set to 1 second. The setting for the T2 period of the car navigation control device 10 is a time shorter than 1 second, and the specific number of seconds for the T1 period varies depending on the type of car navigation system 30. The same applies to the following explanation.

[0090] When the passenger finishes watching television or the like, the car navigation control device 10 transmits the vehicle driving information as it was transmitted from the vehicle electronic control unit 22 to the car navigation system 30 without performing any further calculations regarding the vehicle driving information. The above method is just one example and is not limited to this. The above description assumes that the car navigation system 30 enables viewing of television or the like by processing and calculating only the driving pulse signal from the vehicle driving information. Furthermore, if signals that monitor the driving status of the vehicle 20, such as parking signals, are used, it is necessary to process the parking signals, etc., so that the car navigation system 30 recognizes that the vehicle 20 is stopped, rather than just calculating the driving pulse signal. It is also possible to achieve this using speed data from a signal SG using CAN, etc., as shown by the applicant of the present invention in Japanese Patent Application No. 2025-008442.

[0091] As a result, in a car navigation system 30 that determines whether the location information of the vehicle driving information and the GPS positioning information are different, the car navigation system 30 can use the vehicle driving information to continue watching TV, etc., and continue navigation operation in the background without causing errors. Since it is possible to prevent errors caused by differences in location information between the vehicle driving information and the GPS positioning information, other devices will not be adversely affected by the occurrence of errors. [Industrial applicability]

[0092] The car navigation control device according to the present invention can be used to change the functions of a car navigation system so that it is possible to watch television or the like even while the vehicle is in motion, according to the wishes of passengers in the front passenger seat or rear seat. [Explanation of Symbols]

[0093] 10. Car navigation control unit 11 GPS Control Unit 110 GPS signal processing unit 111 GPS signal processing unit a 112 GPS signal processing unit b 113 GPS signal processing unit c 114 GPS signal processing unit d 115 GPS signal processing unit 12 Arithmetic section 14 Storage section 16 Transmitter / Receiver 17 CAN and other receiving section 18 Bus Line 20 vehicles 22 Vehicle Electronic Control Unit 30. Car navigation system (car navigation) 40 GPS antennas 440 Dummy GPS Antenna 442 Jamming Antenna 50 CAN etc bus line 6th Front Camera 62 Rear camera 64 Illuminance Sensors 66 Front Sonar 68 Rear Sonar SG CAN etc. signal SG1 Vehicle Operation Information SG2 Unprocessed vehicle information or calculated vehicle driving information SG3 GPS received signal SG4 GPS output signal T1 first period T2 second period Time until an error occurs in the t3 car navigation system t3' Maximum time limit to avoid errors in car navigation systems t4 GPS signal interruption period in car navigation control device t5 The time during which the GPS signal is interrupted or positioning is impossible, and the timer variable TC in the car navigation system is reset. Timer elapsed time in TC car navigation system Timer elapsed time in the TC1 car navigation control unit V1 Lower limit of vehicle speed for comparing vehicle driving information and GPS positioning information.

Claims

1. A device connected between a vehicle and a car navigation system to control the car navigation system, Receiving means for receiving vehicle information transmitted from the vehicle to the car navigation system, A calculation means that performs calculations on the aforementioned vehicle information, A storage means for storing the vehicle information by command of the calculation means, A transmission means for transmitting the aforementioned vehicle information or calculated vehicle driving information to the car navigation system, Equipped with, The car navigation system When determining an error based on a mismatch between vehicle driving information and GPS positioning information, The calculation means, The car navigation system is equipped with an error avoidance mechanism that causes the car navigation system to be unable to use GPS positioning information for a predetermined period of time before the mismatch is used for error detection, thereby preventing the car navigation system from recognizing the error. A car navigation control device characterized by the following.

2. The car navigation system When it is detected that the vehicle driving information and GPS positioning information are different location information for a third period of time at a predetermined vehicle speed or higher, or when it is detected that the vehicle driving information and GPS positioning information are different location information exceeding a predetermined tolerance value for a predetermined time or a predetermined number of times within the third period, an error is determined to have occurred. The calculation means, The system includes error avoidance means that detects vehicle driving information indicating that the vehicle is stopped despite being in motion, monitors the elapsed time since detecting that the vehicle speed is above a predetermined speed, and blocks or disables the GPS signal for a fourth period before the elapsed time reaches the third period, thereby preventing the car navigation system from recognizing an error. A car navigation control device according to claim 1, characterized by the following:

3. The calculation means, If the vehicle speed falls below a predetermined speed while monitoring the elapsed time, the monitoring of the elapsed time is stopped and reset to the initial value, and then the monitoring of the elapsed time is stopped again until the vehicle speed reaches or exceeds the predetermined speed. A car navigation control device according to claim 2, characterized by the following:

4. When the GPS antenna fails to acquire the GPS signal from the positioning satellite and positioning becomes impossible, The calculation means, The monitoring of the elapsed time is stopped, the elapsed time is reset to its initial value, and then the monitoring of the elapsed time is stopped again until the GPS antenna can acquire a position. A car navigation control device according to claim 2 or claim 3, characterized by the above.

5. The calculation means, The error avoidance means repeatedly performs continuous or intermittent transmission of vehicle driving information indicating that the vehicle is stopped despite being in motion, from the start until the transmission means terminates. A car navigation control device according to claim 1 or claim 2, characterized by the above.

6. The calculation means, The error avoidance means repeatedly performs continuous or intermittent transmission of vehicle driving information indicating that the vehicle is stopped despite being in motion, from the start until the transmission means terminates. A car navigation control device according to claim 3, characterized by the following:

7. The calculation means, The error avoidance means repeatedly performs continuous or intermittent transmission of vehicle driving information indicating that the vehicle is stopped despite being in motion, from the start until the transmission means terminates. A car navigation control device according to claim 4, characterized by the following:

8. The receiving means, While the acquisition of the vehicle driving information is permitted by the instruction of the calculation means, the system receives some or all of the vehicle driving information transmitted from the vehicle to the car navigation system. The aforementioned storage means The vehicle driving information for the first period and second period, which appear in that order, is stored by the receiving means. The calculation means, The vehicle driving information for the first period and the subsequent second period is used for calculations to be transmitted to the second period, and the calculated information is input into the vehicle driving information. The aforementioned transmission means During the first period mentioned above, vehicle driving information indicating that the vehicle is stopped is used. In the second period mentioned above, the calculated vehicle driving information was used. Sending to the car navigation system. A car navigation control device according to claim 6, characterized by the following:

9. The receiving means, While the acquisition of the vehicle driving information is permitted by the instruction of the calculation means, the system receives some or all of the vehicle driving information transmitted from the vehicle to the car navigation system. The aforementioned storage means The vehicle driving information for the first period and second period, which appear in that order, is stored by the receiving means. The calculation means, The vehicle driving information for the first period and the subsequent second period is used for calculations to be transmitted to the second period, and the calculated information is input into the vehicle driving information. The aforementioned transmission means During the first period mentioned above, vehicle driving information indicating that the vehicle is stopped is used. In the second period mentioned above, the calculated vehicle driving information was used. Sending to the car navigation system. A car navigation control device according to claim 7, characterized by the following:

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