KR101077460B1 - Apparatus for shorting the initalization time in the GPS receiver and method thereof - Google Patents

Abstract

The present invention relates to an apparatus for shortening the initialization time of a GPS receiver and a method thereof.

Particularly, the present invention provides an apparatus and method for shortening the initialization time of a GPS receiver for obtaining satellite position prediction information from a GPS receiver mounted in a nearby vehicle using near field communication in order to shorten the initialization time of the GPS receiver. It is about.

GPS receiver, reset, primary lock time, TTFF

Description

Apparatus for shorting the initalization time in the GPS receiver and method

The present invention relates to an apparatus for shortening the initialization time of a GPS receiver and a method thereof.

Particularly, the present invention provides an apparatus and method for shortening the initialization time of a GPS receiver for obtaining satellite position prediction information from a GPS receiver mounted in a nearby vehicle using near field communication in order to shorten the initialization time of the GPS receiver. It is about.

Currently, positioning technology using a GPS (Global Positioning System) satellite has been widely used in various fields such as vehicle and ship navigation systems, and mobile communication terminals.

Position determination using GPS satellites tracks a GPS satellite signal from a user who wants to measure a location, acquires necessary information from the received GPS satellite signal, and then uses the extracted information on the user's side based on the extracted information. Navigate the location to fix the user's current location. The user equipment that performs this process is called a GPS receiver.

In the above process, the time taken to determine the position by analyzing the satellite signal received from the GPS receiver is called a time to first fix (TTFF), which is one of the important indicators of the performance of the positioning equipment.

An AGPS (Assisted Global Positioning System) has been proposed to solve the primary fixed time (TTFF) and power consumption problems of the receiver.

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

In addition, satellite information that can be obtained from GPS satellites includes satellite position information (Ephemeris) for accurate position and velocity calculations, and satellite orbit information (Almanac) used for approximate position and velocity calculations. The information is valid for approximately four hours from acquisition and the satellite orbit information is valid for approximately six weeks from acquisition.

A cold start is a case in which the GPS receiver calculates a position in the absence of both valid satellite position information and satellite orbit information, and a warm start is used to calculate a position using only valid satellite orbit information. In the case where both valid satellite trajectory information and satellite position information are present, a case where the position calculation is performed immediately is called a hot start. Usually, the first fixed time (TTFF) is long followed by hot start, warm start, and cold start.

On the other hand, the above warm start or hot start is possible because the power unit that can drive a real time clock (RTC) circuit even if the GPS receiver is powered off lastly in a small amount of memory set in advance This is possible by storing the satellite position information, satellite orbit information, last position information and time used for positioning and driving the real time clock circuit.

However, in the case of hot start, the first fixed time can be reduced by storing the information including the satellite position information used for the last positioning, but the satellite position information is valid for up to 4 hours depending on the satellite arrangement.

Therefore, when the GPS receiver is used again after a maximum of 4 hours, the first fixed time is increased due to the time required for receiving satellite position information from the satellite again.

In order to reduce the first fixed time required when the GPS receiver is driven again, a method of using the position prediction information valid for several days has been developed. The developed method calculates and generates the satellite position prediction information in a separate server and then uses the GPS. It can be downloaded and used on the receiver, or it can be calculated directly from the GPS receiver to generate satellite position prediction information.

However, the method of generating the satellite position prediction information in the first server is not widely used due to the cost incurred by the separate server operation and the inconvenience of downloading the information through the Internet, and the method of generating the satellite position directly from the GPS receiver is in the spotlight.

The method of generating satellite position prediction information in a GPS receiver is a method of receiving data from a satellite, generating satellite position prediction information for a corresponding satellite, and using it later.

In this method of generating satellite position prediction information in the GPS receiver, while the method using a server may have information on all satellites, the satellite position prediction for the satellites that have actually received the signal is generated because the signal is generated directly using the satellite signal. Only information can be generated.

Therefore, when the satellites visible when the satellite position prediction information is generated and the satellites visible when the GPS receiver is operated again later, the satellite fixed position prediction information is not valid, and thus the first fixed time reduction effect cannot be seen.

Accordingly, the present invention has been made to solve the above problems, so that when the GPS receiver is operated in order to shorten the first fixed time, it is possible to secure satellite position prediction information for other satellites as well as traceable satellites. It is an object of the present invention to provide a device and a method for reducing the initialization time of the GPS receiver to reduce the primary fixed time.

In order to achieve the above object, the present invention receives the GPS data from the GPS satellite, calculates and stores the satellite position prediction information, and when the satellite position prediction information transmission request is received, the stored satellite position prediction information is transmitted. A first GPS receiver; And when driven on, the satellite information is checked and the satellite position information is present. If the satellite position information and the satellite position prediction information are not valid among the satellite information, the satellite position prediction information is transmitted to the first GPS receiver. And a second GPS receiver which calculates a position by tracking and fixing the satellite according to the received satellite position prediction information by receiving the prediction information.

In addition, the first GPS receiver of the present invention, the first wireless processing unit for receiving the GPS data from the GPS satellite; A first digital processor configured to calculate satellite position prediction information from GPS data received by the first wireless processor; A first memory for storing satellite position prediction information calculated by the first digital processor; A first short range wireless communication unit configured to receive a satellite position prediction information transmission request and to transmit satellite position prediction information; And a first control unit controlling to store the satellite position prediction information calculated by the first digital processing unit in the first memory and to transmit the satellite position prediction information stored in the first memory through the first short range wireless communication unit. Characterized in that comprises a.

The first GPS receiver of the present invention may further include a first power supply unit for supplying power to the first control unit and the first memory when the power supply is interrupted.

In addition, the second GPS receiver of the present invention includes a second radio processor for receiving GPS data by tracking a satellite signal from the GPS satellite according to the satellite position prediction information; A second digital processing unit for calculating a position from the GPS data received by the second wireless processing unit; A second memory for storing the calculated position; A second short range wireless communication unit which transmits a satellite position prediction information transmission request and receives satellite position prediction information; And when it is turned on and driven, when the satellite position information exists and the satellite position information is present, if the satellite position information is not valid among the satellite information and the satellite position prediction information is not valid, the second short range wireless communication unit transmits the first GPS receiver to the first GPS receiver. Request to transmit the satellite position prediction information, control to receive the satellite position prediction information, and control the second wireless processor to track and fix the satellite according to the received satellite position prediction information to calculate the position in the second digital processor. And a second control unit for controlling.

In addition, the second digital processing unit of the second GPS receiver of the present invention calculates the satellite position prediction information from the GPS data received by the second radio processing unit and stores in the second memory, the control unit transmits the satellite position prediction information When the request is received, the second local area communication unit is controlled to transmit the stored satellite position prediction information.

In addition, the communication method of the first GPS receiver and the second GPS receiver of the present invention is a short-range communication method characterized in that it comprises at least any one of the RFID, Bluetooth, WLAN.

In addition, the present invention (A) when the GPS receiver is turned on and driven, by checking the satellite information to determine whether the satellite position information and satellite position prediction information is valid, when the satellite information is present; (B) if it is not valid, requesting satellite position prediction information from a nearby GPS receiver to receive satellite position prediction information; And (C) the GPS receiver calculating the position by tracking and fixing the satellite signal using the received position prediction information if the satellite position prediction information received from the surrounding GPS receiver is valid. It is done.

In addition, the present invention is characterized in that it further comprises the step of determining the position by performing a cold start (D) if the GPS receiver is turned on, if the satellite information does not exist, if the satellite information does not exist.

In addition, the step (A) of the present invention, (A-1) when the GPS receiver is turned on and driven, confirming the satellite information; (A-2) confirming the satellite information and confirming that the satellite location information is valid when the satellite information exists; And (A-3) confirming that the satellite position information is valid, if not, checking whether the satellite position prediction information is valid.

In addition, the present invention is characterized in that it further comprises the step of determining the position by performing a warm start if the satellite position prediction information received from the GPS receiver around (E) is not valid.

According to the present invention as described above, since the GPS receivers mounted on the vehicle share the information collected from each other, it is possible to effectively reduce the primary fixed time.

In addition, according to the present invention, since information sharing through short-range wireless communication needs to be used only once in the initial stage of operation of the GPS receiver, there is an effect of operating with low power consumption.

Now, the initialization time reduction apparatus and method thereof of the GPS receiver according to the present invention will be described in detail with reference to the drawings below.

3 is a block diagram of an apparatus for reducing initialization time of a GPS receiver according to an embodiment of the present invention.

Referring to FIG. 3, an apparatus for shortening the initialization time of a GPS receiver according to an exemplary embodiment of the present invention includes at least two first and second GPS receivers 110 and 110 ′ provided in each vehicle.

Each of the first or second GPS receivers 110 or 110 'may include a wireless processor 111, 111', a digital processor 112, 112 ', a controller 113, 113', and a real time clock (RTC) circuit. (114, 114 '), near field communication unit (115, 115'), memory (118, 118 '), input (119, 119'), power supply (120, 120 ').

In addition, the short range wireless communication unit 115, 115 ′ includes a data transmitter 116, 116 ′ and a data receiver 117, 117 ′.

In the first and second GPS receivers 110 and 110 ′ configured as described above, the wireless processing units 111 and 111 ′ receive the GPS data from the GPS satellites, and thus the digital processing units 112 and 112 ′ and the control units 113 and 113 ′. To send). The GPS data includes location information (ephemeris) of the GPS satellite, almanac of the satellite and GPS time information (GPS Time).

The digital processing units 112 and 112 'calculate the position using the GPS data received by the wireless processing units 111 and 111', and calculate the satellite position prediction information.

The controllers 113 and 113 'perform an overall control operation. In particular, when the wireless processing units 111 and 111 'receive the GPS data from the GPS satellites, the controllers 113 and 113' store the received GPS data in the memories 118 and 118 '.

When the digital processing units 112 and 112 'calculate the positions, the controllers 113 and 113' display the calculated positions on the display unit (not shown) or output them to the outside.

In addition, the controllers 113 and 113 'may be further configured to transmit the first or other first data through the data transmitters 116 and 116' of the short range wireless communication unit 115 and 115 'based on the satellite position prediction information calculated by the digital processor 112 and 112'. Transmit to the second GPS receiver (110, 110 ').

Next, the real time clock circuits 114 and 114 'generate and provide the real time clock to the digital processing units 112 and 112' and the control units 113 and 113 '.

The short range wireless communication units 115 and 115 'may communicate with each other by a short range wireless method, and the short range wireless communication method may include at least one of an infrared data association (IrDA), a Bluetooth, and a wireless LAN. It is also possible to be implemented in a short-range wireless communication method of.

The data receivers 117 and 117 'of the short range wireless communication unit 115 and 115' receive the satellite position prediction information transmission request signal from the other first or second GPS receivers 110 and 110 'and control the controllers 113 and 113. Send it to ').

The data transmitters 116 and 116 'of the short range wireless communication unit 115 and 115' transmit the satellite position prediction information calculated by the digital processor 112 and 112 'to each other.

The memories 118 and 118 'store programs and data necessary for overall operation. In particular, the memories 118 and 118 'store GPS data received by the wireless processing units 111 and 111', position information calculated by the digital processing units 112 and 112 ', and satellite position prediction information.

Next, the input units 119 and 119 ′ may include a touch pad or a keypad provided with various function keys, numeric keys, special keys, character keys, and the like. 119 ′ is a control signal (eg, first or second GPS) of the first or second GPS receiver 110, 110 ′ for controlling the operation of the first or second GPS receiver 110, 110 ′. The driving signal of the receiver) is input from the user and transmitted to the controllers 113 and 113 '.

The power supply units 120 and 120 'include the wireless processing units 111 and 111', the digital processing units 112 and 112 ', the control units 113 and 113', the real time clock circuits 114 and 114 ', and the near field communication unit 115, 115 '), auxiliary memory is supplied when the external power supply is interrupted to the memory 118, 118', input unit 119, 119 ', and the like.

Now, the operation of the initialization shortening device of the GPS receiver according to an embodiment of the present invention will be described in detail with reference to FIG. 3.

First, the wireless processing units 111 and 111 ′ of the first or second GPS receivers 110 and 110 ′ receive GPS data from GPS satellites and transmit the GPS data to the digital processing units 112 and 112 ′ and the control units 113 and 113 ′. to provide.

Then, the digital processing units 112 and 112 'continuously process the input GPS data to calculate the position of the first or second GPS receivers 110 and 110'.

Since the local time reference of the first or second GPS receivers 110 and 110 'includes an error, the digital processing unit 112 and 112' needs to synchronize the local time reference to the GPS satellite time information.

In addition, in order to reduce the first fixed time, the digital processing unit 112 and 112 'may also generate and store satellite position information, satellite orbit information, satellite position prediction information, and the like in the memory 118 and 118' at a predetermined time period. have. The memory 118, 118 ′ may store backup satellite information and may prevent the loss of backup satellite information through continuous power supply when the first or second GPS receiver 110, 110 ′ is not powered.

If the first or second GPS receiver 110, 110 'is not powered (off) or the power delivered to the first or second GPS receiver 110, 110' is accidentally cut off, The power supply unit 120, 120 ′ supplies power to the memory 118, 118 ′ and the real time clock circuits 114, 114 ′.

Therefore, when the power supply to the first or second GPS receivers 110 and 110 'is cut off, the power supply units 120 and 120' preserve the backup satellite information stored in the memory 118 and 118 'and the real-time clock circuit. Ensure that (114, 114 ') continues to work.

When the first or second GPS receiver 110, 110 ′ is powered again (on), the digital processing unit 112, 112 ′ reads back-up satellite information stored in the memory 118, 118 ′ and reads the real-time clock circuit. Obtain the local time reference provided by (114, 114 ').

Although the local time reference provided by the real time clock circuits 114 and 114 'contains an error, the local time reference may be used to verify backup satellite information stored in the memory 118 and 118'.

In order to confirm the backup satellite information, the digital processing units 112 and 112 'need to calculate the time interval between the local time reference and the time mark provided from the backup satellite information.

If the time interval exceeds a predetermined period, the first or second GPS receiver 110, 110 'receives satellite position prediction information from the first or second GPS receiver 110, 110' mounted in the surrounding vehicle. In order to obtain, the satellite position prediction information transmission request signal is transmitted to the first or second GPS receivers 110 and 110 'mounted in the surrounding vehicles, and the first or second GPS receivers 110 and 110 mounted in the cold vehicle are obtained. ') To obtain satellite position prediction information.

The first or second GPS receivers 110 and 110 'acquire satellite position prediction information when the satellite position prediction information is obtained from the first or second GPS receivers 110 and 110' detected in the surrounding vehicle. It is determined whether the satellite signal tracking of the GPS satellite is possible (by determining whether the satellite position prediction information is valid), and if the satellite signal tracking is possible from the GPS satellite, the satellite is tracked and fixed to fix the GPS data. Receive.

In addition, the first or second GPS receiver 110, 110 'is not capable of tracking satellite signals from the GPS satellite (unless the backup satellite position prediction data is invalid). The first or second GPS receivers 110, 110 ′ begin to acquire GPS satellite signals over a wide frequency range. As a result, acquisition of 4 GPS satellite signals takes a lot of time.

4 is a flowchart of a method for shortening initialization of a GPS receiver according to an embodiment of the present invention.

Referring to FIG. 4, in the initialization shortening method of the GPS receiver according to an exemplary embodiment of the present invention, when the GPS receiver is turned on, the controller checks whether satellite information stored in the memory exists (S110).

If the satellite information does not exist, the controller performs a cold start (S111), receives GPS data from the GPS satellites, and determines a location (S118). In this case, the cold start refers to receiving all satellite information such as satellite position information, satellite orbit information, and satellite time information from the satellite to determine the position.

Next, when the satellite information exists in the memory, the controller checks whether the satellite position information is valid in the satellite information (S112) and determines whether the satellite position information is valid (S114).

As a result of the determination, if the satellite position information is valid (if the current time and the generation time of the last satellite position information are within 4 hours), a hot start is performed (S116) to determine the position (S118). Here, the hot start is a mode for positioning the position by the current time known by the satellite position information, the satellite orbit information, the last position, and the real time clock circuit stored before the GPS receiver is powered off.

On the other hand, if the satellite position information is invalid as a result of the determination, it is determined whether the satellite position prediction information is valid (S120). Here, the determination of whether the satellite position prediction information is valid is determined whether it is possible to receive a satellite signal from the GPS satellite corresponding to the satellite position prediction information, and it is determined that it is valid if the satellite signal can be received from the GPS satellite. If a satellite signal cannot be received from the terminal, it is determined to be invalid.

As a result of the determination, if the satellite position prediction information is valid, the position is determined by the satellite position prediction information, the satellite orbit information, the last position measured, and the current time known by the real time clock circuit, before the GPS receiver is turned off. Using the start (S124), the position is measured (S118).

As a result of the determination of the validity of the satellite position prediction information, if the satellite position prediction information is not valid, a request is made to transmit the satellite position prediction information to the surrounding GPS receiver (S126).

When satellite position prediction information is received from the surrounding GPS receivers (S128), it is determined whether the received satellite position prediction information is valid (S128, S130).

As a result of the determination, if the satellite position prediction information received from the surrounding GPS receiver is valid, the start is performed by the received satellite position prediction information, the satellite orbit information, the last positioning position, and the current time known by the real time clock circuit. (S134), the position is determined (S118).

As a result of the determination, if the satellite position prediction information received from the surrounding GPS receiver is not valid, a warm start is performed (S136) and positioning is performed (S118). In this case, the warm start is a mode in which the GPS receiver uses the satellite orbit information, the last position, and the current time information known by the real time clock circuit before the power is turned off. Receive from and locate.

1 is a block diagram illustrating a general AGPS system.

2 is a signal flow diagram illustrating the general operation of an AGPS receiver.

3 is a block diagram of an apparatus for reducing initialization time of a GPS receiver according to an embodiment of the present invention.

4 is a flowchart of a method for reducing initialization time of a GPS receiver according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

110, 110 ': GPS receiver 111, 111': wireless processing unit

112, 112 ': digital processing unit 113, 113: control unit

114, 114 ': Real time clock circuit 115, 115': Near field communication unit

116, 116 ': data transmitter 117, 117': data receiver

118, 118 ': Memory 119, 119': Input section

120, 120 ': Power supply part

Claims (10)

delete A first GPS receiver which receives GPS data from the GPS satellites, calculates and stores satellite position prediction information, and transmits the stored satellite position prediction information when the satellite position prediction information transmission request is received; And When it is turned on and driven, if satellite position information exists by checking satellite information, and satellite position information and satellite position prediction information are not valid among the satellite information, requesting the first GPS receiver to transmit satellite position prediction information, satellite position prediction is performed. And receiving a second GPS receiver for calculating a location by tracking and fixing satellites according to the received satellite position prediction information. The communication method of the first GPS receiver and the second GPS receiver is a short-range communication method, characterized in that it comprises at least any one of the RFID, Bluetooth, WLAN. The first GPS receiver, A first wireless processor configured to receive GPS data from a GPS satellite; A first digital processor configured to calculate satellite position prediction information from GPS data received by the first wireless processor; A first memory for storing satellite position prediction information calculated by the first digital processor; A first short range wireless communication unit configured to receive a satellite position prediction information transmission request and to transmit satellite position prediction information; And A first control unit controlling to store the satellite position prediction information calculated by the first digital processing unit in the first memory, and controlling to transmit the satellite position prediction information stored in the first memory through the first short range wireless communication unit; Device for reducing the initialization time of the GPS receiver, including. 3. The method of claim 2, The first GPS receiver, And a first power supply unit for supplying power to the first control unit and the first memory when the power supply is interrupted. A first GPS receiver which receives GPS data from the GPS satellites, calculates and stores satellite position prediction information, and transmits the stored satellite position prediction information when the satellite position prediction information transmission request is received; And When it is turned on and driven, if satellite position information exists by checking satellite information, and satellite position information and satellite position prediction information are not valid among the satellite information, requesting the first GPS receiver to transmit satellite position prediction information, satellite position prediction is performed. And receiving a second GPS receiver for calculating a location by tracking and fixing satellites according to the received satellite position prediction information. The communication method of the first GPS receiver and the second GPS receiver is a short-range communication method, characterized in that it comprises at least any one of the RFID, Bluetooth, WLAN. The second GPS receiver, A second wireless processor for receiving GPS data by tracking a satellite signal from the GPS satellite according to the satellite position prediction information; A second digital processing unit for calculating a position from the GPS data received by the second wireless processing unit; A second memory for storing the calculated position; A second short range wireless communication unit which transmits a satellite position prediction information transmission request and receives satellite position prediction information; And When it is turned on and driven, when satellite position information is checked and satellite position information is present, if the satellite position information is not valid among the satellite information and the satellite position prediction information is not valid, the satellite is connected to the first GPS receiver in the second short range wireless communication unit. Request transmission of the position prediction information, and control to receive the satellite position prediction information, and control the second radio processor to track and fix the satellite according to the received satellite position prediction information to calculate the position in the second digital processor Initializing time reduction device of the GPS receiver comprising a second control unit. The method of claim 4, wherein The second digital processing unit of the second GPS receiver calculates satellite position prediction information from GPS data received by the second radio processing unit and stores the satellite position prediction information in the second memory. And the controller controls the second short range communication unit to transmit the stored satellite position prediction information when the satellite position prediction information transmission request is received. delete delete (A) if the GPS receiver is turned on and driven, checking the satellite information to determine whether the satellite position information and the satellite position prediction information are valid when the satellite information exists; (B) if it is not valid, connecting to a nearby GPS receiver through at least one of a near field communication method such as IDD, Bluetooth, or WLAN, and requesting satellite position prediction information to receive satellite position prediction information; (C) calculating, by the GPS receiver, tracking and fixing the satellite signal using the received position prediction information if the satellite position prediction information received from the surrounding GPS receiver is valid; And (D) when the GPS receiver is turned on and driven, if the satellite information does not exist by checking the satellite information, performing a cold start to determine a position of the GPS receiver. (A) if the GPS receiver is turned on and driven, checking the satellite information to determine whether the satellite position information and the satellite position prediction information are valid when the satellite information exists; (B) if it is not valid, connecting to a nearby GPS receiver through at least one of a near field communication method such as IDD, Bluetooth, or WLAN, and requesting satellite position prediction information to receive satellite position prediction information; And (C) the GPS receiver calculating the position by tracking and fixing the satellite signal using the received position prediction information if the satellite position prediction information received from the surrounding GPS receiver is valid, Step (A) is (A-1) checking the satellite information when the GPS receiver is turned on and driven; (A-2) confirming the satellite information and confirming that the satellite location information is valid when the satellite information exists; And (A-3) A method of reducing the initialization time of a GPS receiver, comprising checking whether the satellite position information is valid, and if not, checking whether the satellite position prediction information is valid. (A) if the GPS receiver is turned on and driven, checking the satellite information to determine whether the satellite position information and the satellite position prediction information are valid when the satellite information exists; (B) if it is not valid, connecting to a nearby GPS receiver through at least one of a near field communication method such as IDD, Bluetooth, or WLAN, and requesting satellite position prediction information to receive satellite position prediction information; (C) calculating, by the GPS receiver, tracking and fixing the satellite signal using the received position prediction information if the satellite position prediction information received from the surrounding GPS receiver is valid; And (D) a method for shortening the initialization time of a GPS receiver, comprising: performing a warm start to determine a position if satellite position prediction information received from a nearby GPS receiver is invalid.

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