TWI383127B - Method for velocity estimation in gps dead reckoning - Google Patents

Description

Speed calculation method for assisting navigation

The invention discloses a speed calculation technology method for assisting navigation, in particular to a technology for speed calculation of the auxiliary navigation system not interrupting navigation when the navigation system cannot effectively receive the global positioning system (GPS) positioning information. method.

The Global Positioning System (GPS) is a technology developed by the US military using space technology. The principle is to use the satellite synchronized with the Earth to take its relative position and measure the precise position of the user in three-dimensional space. This technology has the advantages of all-weather, global coverage and fast time-saving and high efficiency.

After the GPS system is partially transferred to the private sector, in addition to the precise timing, engineering construction and exploration mapping, the most relevant to our daily life is the application of car navigation. Firstly, a GPS navigation device is installed on the car for receiving GPS positioning information, and with the pre-stored map information, the driver can provide accurate and immediate positioning and movement information through the navigation software. This eliminates the inconvenience of the driver according to the drawings, greatly improving the convenience of driving.

Of course, even with a number of advantages, GPS navigation is still a flaw in the practical. In addition to the possible temporary failure of the GPS satellite itself, its positioning function relies on the signals emitted by the satellite from space, solar wind, atmospheric concentration changes, building refracting and shelter (such as tunnels, bridges or parking lots). Impact can cause navigation interruption or misjudgment.

In response to the above situation, it can usually be solved in the following three directions: one is to enhance the receiving performance, the other is to seek a temporary alternative to the secondary navigation (Dead Reckoning; DR) technology, and the other is to use the reference station settings. To correct the GPS error.

In terms of enhancing reception efficiency, such as the Republic of China Patent Publication No. I271535 "Global Positioning System (GPS) antenna adjustment system and method and GPS satellite signal strength display module and method", it is disclosed that a satellite signal strength measurement data is generated for antenna adjustment, A method to improve the reception performance of an antenna.

In the search for a temporary alternative DR technology, when the signal source is interrupted, the navigation system automatically switches to the auxiliary navigation mode, and the wheel speed sensor obtains the traveling speed of the car, and the pre-stored map information is used to track the user positioning and continuously navigate.

In the use of the setting of the reference station to correct the GPS error, the most typical one is the conventional technology ground differential positioning system (Differential GPS (hereinafter referred to as DGPS), which uses the setting of the reference station to correct the GPS error, and then broadcast the instant. The error value is used by the user within the message transmission range to add an operation to correct the error. In the Republic of China Patent Publication No. I227332, "A device and method for correcting GPS/DGPS positioning deviation and eliminating shadowing obstacles", a method of fixed-point short-range communication is further proposed, thereby improving the accuracy by more than 98%.

Among these solutions, compared with the higher demand of DGPS on the equipment, although the current DR technology is not high in accuracy, it has high applicability, so it is widely developed by manufacturers. However, in the current application of the wheel speed sensor in the DR technology, the estimation of the traveling speed may cause an error in the following cases: the wheel sliding travel, the tire pressure or the wear factor of the tire itself causes the tire radius to change, And sensor contamination, etc. The present invention is directed to the existing DR technology, the lack of the application of the wheel speed sensor, and another solution for the determination of the travel speed.

In view of the GPS navigation technology provided by the prior art, there is a serious problem that the GPS satellite itself may be temporarily damaged, and the adverse factors such as foreign object shielding or interference may cause a navigation interruption. Therefore, the present invention aims to provide a speed calculation method for assisting navigation and an application device thereof, which provides a speed calculation information in an assisted inertial navigation system that continuously provides positioning information when a GPS navigation system signal is interrupted.

The technical means for solving the problems of the prior art provides a GPS navigation system terminal device, comprising a memory unit, an image capturing unit, a timer and a processing unit, and the processing unit has an image computing module. . When the GPS navigation system terminal device cannot effectively receive a GPS positioning information, a plurality of road surface images can be automatically captured, and one end of the traffic marking line is calculated by identifying one end point of the traffic marking line. Alternatively, a unit time is defined, and a displacement length is determined by identifying the end point of the traffic marking. The length of the traffic marking or the length of the displacement may represent the travel distance of one of the users. The processing unit uses the image computing module to divide the travel distance by the unit time to obtain a speed, and accordingly provides the navigation screen.

Compared with the conventional GPS navigation system, since the present invention comprises a memory unit, an image capturing unit, a timer and a processing unit, the speed information of the driver can be determined by capturing the real scene of the road surface, which is effective. Solve the above problem of "interruption of GPS navigation caused by foreign objects such as shelters." Even if the driver is in a bad climate, there is a problem in the sky, or the GPS navigation fault, the speed calculation result obtained by the present invention is combined with the map information pre-stored in the GPS navigation system terminal device by the switching of the auxiliary navigation mode, the driver It is still possible to achieve its own positioning and moving direction to improve navigation accuracy and ensure driving safety.

Moreover, compared with the conventional DR technology, the application of the wheel speed sensor eliminates the misjudgment of the wheel speed sensor in the case of wheel sliding travel, tire pressure or tire wear factor causing tire radius change, and sensor fouling. Missing.

Finally, compared to DGPS technology, the technology cost of the present invention is largely low, and widespread application is just around the corner.

The combination of the embodiments of the present invention is numerous and will not be repeated here, but only two preferred embodiments will be specifically described.

Referring to the first to fourth figures, in the preferred embodiment of the present invention, a Global Positioning System (GPS) navigation system is implemented by combining a vehicle to implement navigation technology; A functional block diagram showing a preferred embodiment of the present invention; The three figures show a schematic diagram of a vehicle that enters a sheltered area and travels on a line segment having a traffic marking in a preferred embodiment of the present invention; and a fourth diagram is a schematic diagram of the image capturing unit capturing a road image.

As shown, a Global Positioning System (GPS) navigation system 100 includes a GPS navigation system terminal device 1 and three GPS satellites 2, 2a and 2b. The GPS navigation system terminal device 1 is installed in a carrier 200, and the GPS satellite 2 continuously transmits a GPS positioning signal S1 to the earth.

The GPS navigation system terminal device 1 includes a processing unit 11, a memory unit 12, an image capturing unit 13, a display unit 14, a signal receiving unit 16, and a timer 17. The processing unit 11 has an image computing module 111. The image computing module 111 includes an image determining program 1111 and a speed computing program 1112.

The memory unit 12, the image capturing unit 13, the display unit 14, the signal receiving unit 16, and the timer 17 are electrically connected to the processing unit 11, respectively, and the image capturing unit 13 can be a charge coupled device (CCD). ). The memory unit 12 prestores at least one map information 121.

As shown in the third figure, in the normal navigation state, the signal receiving unit 16 can receive the GPS positioning signal S1, thereby receiving the GPS positioning information 122 sent by the GPS positioning signal S1. The GPS positioning signal S1 can generally be a signal that satisfies the International Marine Electronics Association 0183 (NMEA 0183) communication protocol.

When a driver (not shown) drives the vehicle 200 into the section A and travels within the shielding range of a shelter 300, the signal receiving unit 16 cannot effectively receive the GPS positioning signal S1, causing the normal navigation state to be interrupted. . Among them, the road section A has a traffic marking 3, which is a dotted line and includes at least one unit line segment 31, and the length L1 and the interval length L2 of the unit line segment 31 are 4 meters and 6 meters, respectively. It should be specially noted that the lengths L1 and L2 are not limited to this. At this point, it will enter an auxiliary navigation state.

As shown in the fourth figure, when the GPS navigation system terminal device 1 enters the auxiliary navigation state, the image capturing unit 13 is turned on and the road surface image of the road segment A is captured as a plurality of road surface images 18 according to an image capturing range R, wherein The image capture range R covers traffic markings 3.

Next, referring to FIG. 5 to FIG. 5B, in the first embodiment of the present invention, the image determination program determines a schematic diagram of the continuously captured road image. The road surface image 18 is transmitted to the processing unit 11 to define an end point identification range ER around the road surface image 18 by the image computing module 111, and to identify one of the unit line segments 31' of the traffic marking line 3' in the road surface image 18. An endpoint 311' and a second endpoint 312'. As shown in the fifth figure, if the first end point 311' is located within the endpoint identification range ER and is close to the upper edge of the road image 18, the representative vehicle 200 is about to travel through the unit line segment 31, and the image judging program 1111 is defined accordingly. The start time is taken by the timer 17. As shown in Fig. A, if the position of the first end point 311' falls outside the end point recognition range ER, the image judging program 1111 does not operate. As shown in FIG. 5B, if the second end point 312' is located within the endpoint identification range ER and is close to the lower edge of the road image 18, the representative vehicle 200 is about to leave the unit line segment 31, and the image determination program 1111 accordingly A termination time is defined for the timer 17 to retrieve. The timer 17 calculates a unit time by taking the start time and the end time, which represents the time taken for the carrier 200 to travel through the unit line segment 31.

Then, the image operation module 111 is returned to the unit time. The speed calculation program 1112 obtains a traveling speed by dividing the length L1 of the unit line segment 31 by the unit time. Travel speed with map information 121 synthesis The operation generates a navigation screen 141 and is presented on the display unit 14. The length L1 of the unit line segment 31 is defined according to the setting rules of the road traffic markings of the Republic of China.

Please refer to FIG. 6 to FIG. 6A. In the second embodiment of the present invention, the image determining program determines a schematic view of the continuously captured road image, and please refer to the second and third figures together. The timer 17 defines a unit time for the image capturing unit 13 to take the road surface as the road image 18 continuously. Among them, the road image 18 covers the traffic markings 3. Then, the road image 18 is transmitted to the processing unit 11 to be used in the image computing module 111. The image determining program 1111 is provided before the image capturing magnification and the focal length of the image capturing unit 13 are fixed, and the scale is defined as one of the perspective principles. . The image judging program 1111 divides the road image 18 according to the scale 19 to facilitate subsequent recognition and judgment. At this time, as shown in the sixth figure, the image determination program 1111 recognizes the first end point 311' of the unit line segment 31' in the road surface image 18, and as shown in the sixth A diagram, identifies the first end point of the unit line segment 31" 311", and thereby determining the displacement length M of the first end point 311' to the first end point 311" in a unit time. Then, the image determining program 1111 calculates the displacement length M according to the scale 19 to calculate an actual displacement length. The speed calculation program 1112 divides the actual displacement length (not shown) by the unit time, that is, obtains the traveling speed. The traveling speed is integrated with the map information 121 to generate a navigation screen 141 and is presented on the display unit 14.

Then, in order to further promote the technology disclosed in the present invention, the techniques disclosed in the first embodiment and the second embodiment of the present invention are further summarized as a simple flowchart so as to have a general knowledge in the technical field. It's easier to remember.

Please refer to the seventh and eighth figures, which are simplified flowcharts of the first embodiment of the present invention, and please refer to the second figure together. as the picture shows, In implementing the techniques of the present invention, the GPS navigation system terminal device 1 must first be turned on to enter the GPS navigation system 100 (step 110). Next, the signal receiving unit 16 receives the GPS positioning signal S1 complying with the NMEA 0183 communication protocol, thereby obtaining the GPS positioning information 122 carried by it (step 120). At this time, the GPS navigation system terminal device 1 determines whether the signal receiving unit 16 effectively receives the GPS positioning signal S1 (step 130). If so, the GPS navigation system terminal device 1 automatically turns on the image capturing unit 13 (step 140), and then extracts the road surface having the traffic marking 3 into a plurality of road surface images 18 covering the traffic markings 3 (step 150). .

Next, the image judging program 1111 judges whether or not the first end point 311' of the unit line segment 31' of the traffic marking line 3' appears in the end point identification range ER (step 160). If so, the image determination program 1111 further determines whether the first end point 311' is close to the upper edge of the road image 18 (step 170). If so, the image judging program 1111 generates a start time for the timer 17 to capture (step 180).

After the timer 17 draws the start time, the image determining program 1111 continues to determine whether the second end point 312' of the unit line segment 31' of the traffic marking 3' in the road image 18 is within the endpoint identification range ER ( Step 190)? If so, the image determination program 1111 further determines whether the second end point 312' is close to the lower edge of the road image 18 (step 210). If so, the image judging program 1111 generates an end time for the timer 17 to capture. After the timer 17 has taken the end time, a unit time is generated (step 220). The speed calculation program 1112 divides the unit time by the length L1 of the unit line segment 31, that is, calculates the traveling speed (step 230). Finally, the operation result can be displayed on the navigation screen 141 in conjunction with the map information 121 (step 240).

Please refer to the ninth figure, which is a simplified flowchart of the second embodiment of the present invention, and please refer to the second figure. In the second embodiment of the present invention In this case, the GPS navigation system terminal device 1 must be turned on first to enter the GPS navigation system 100 (step 310). Next, the signal receiving unit 16 receives the GPS positioning signal S1 complying with the NMEA 0183 communication protocol, thereby obtaining the GPS positioning information 122 carried by it (step 320). At this time, the GPS navigation system terminal device 1 determines whether the signal receiving unit 16 effectively receives the GPS positioning signal S1 (step 330). If not, the GPS navigation system terminal device 1 automatically turns on the image capturing unit 13 (step 340).

At this time, the timer defines a unit time as the interval between the image capturing by the image capturing unit 13 (step 350). The image capturing unit 13 continuously captures the road surface image as the road surface image 18 at intervals of unit time, wherein the road surface image 18 covers the traffic marking line 3 (step 360). The image judging program 1111 defines a scale 19 in accordance with the take-up magnification of the image capturing unit 13 (step 370). Then, the image judging program 1111 recognizes the end point of the unit line segment 31' (such as the first end point 311') in the continuously captured road image 18, and judges its displacement (such as judging from the first end point 311' to the first The displacement of the end point 311" is generated to generate a displacement length M (step 380). The image determination program 1111 calculates the displacement length M as the actual displacement length (not shown) according to the scale 19 (step 390). The speed calculation program 1112 The actual displacement length (not shown) is divided by the unit time, that is, the traveling speed is calculated (step 400). Finally, the operation result can be displayed on the navigation screen 141 in conjunction with the map information 121 (step 410).

As is well known in the art, as is well known in the art, the GPS navigation system terminal device 1 includes an image capturing unit 13, a timer 17 and a conventional GPS navigation system. The processing unit 11 has a video computing module 111, so that the driving speed of the driver can be determined by capturing the real scene of the road surface, thereby effectively solving the above problem. "The problem of GPS navigation being interrupted due to foreign objects such as the shield 300." Even if the driver is in a bad climate, there is a problem in the sky, or a GPS navigation failure, the speed calculation result obtained by the present invention is combined with the map information pre-stored in the GPS navigation system terminal device 1 by the switching of the auxiliary navigation mode. The person still can obtain his own positioning and moving direction; in addition, compared with the conventional DR technology, the application of the wheel speed sensor, the invention eliminates the tire radius caused by the wheel speed sensor in the wheel sliding travel, the tire pressure or the tire itself wear factor Changes, as well as the lack of misjudgment in the case of sensor fouling. The present invention does improve navigation accuracy and ensures driving safety.

It can be seen from the above embodiments of the present invention that the present invention has industrial utilization value. The above embodiments are merely illustrative of the preferred embodiments of the present invention, and those skilled in the art will be able to make various other modifications and changes in the embodiments described herein. However, various modifications and changes made in accordance with the embodiments of the present invention are still within the scope of the invention and the scope of the invention.

100‧‧‧GPS navigation system

200‧‧‧ Vehicles

300‧‧‧ Shield

1‧‧‧GPS navigation system terminal device

11‧‧‧Processing unit

111‧‧‧Image Computing Module

1111‧‧‧Image Judging Program

1112‧‧‧Speed calculation program

12‧‧‧ memory unit

121‧‧‧Map Information

122‧‧‧GPS positioning information

13‧‧‧Image capture unit

14‧‧‧Display unit

141‧‧‧Navigation screen

16‧‧‧Signal receiving unit

17‧‧‧Timer

18‧‧‧Pavement imagery

19‧‧‧ scale

2‧‧‧GPS satellite

2a‧‧‧GPS satellite

2b‧‧‧GPS satellite

3, 3’‧‧‧ traffic markings

31, 31’‧‧‧ unit line segment

311, 311', 311" ‧ ‧ first endpoint

312’‧‧‧second endpoint

S1‧‧‧GPS positioning signal

A‧‧‧ section

R‧‧‧Image capture range

ER‧‧‧ endpoint identification range

M‧‧‧ displacement length

L1‧‧‧unit line length

L2‧‧‧ interval length

The first figure shows that in a preferred embodiment of the present invention, a Global Positioning System (GPS) navigation system implements navigation technology in combination with a carrier; the second figure shows the functions of the preferred embodiment of the present invention. The third diagram shows a schematic diagram of a vehicle that enters a sheltered area and travels on a line segment having a traffic marking in a preferred embodiment of the present invention; and a fourth diagram of the image capturing unit capturing a road image. ; Fifth, fifth, and fifth diagrams In the first embodiment of the present invention, the image determination program determines a schematic diagram of the continuously captured road image. 6 and 6A are diagrams showing the image of the continuously captured road image in the second embodiment of the present invention; the seventh and eighth figures show the embodiment of the first embodiment of the present invention. A simplified flow chart; and a ninth drawing show a simplified flow chart of an embodiment of the second embodiment of the present invention.

100‧‧‧GPS navigation system

1‧‧‧GPS navigation system terminal device

11‧‧‧Processing unit

111‧‧‧Image Computing Module

1111‧‧‧Image Judging Program

1112‧‧‧Speed calculation program

12‧‧‧ memory unit

121‧‧‧Map Information

122‧‧‧GPS positioning information

13‧‧‧Image capture unit

14‧‧‧Display unit

141‧‧‧Navigation screen

16‧‧‧Signal receiving unit

17‧‧‧Timer

2‧‧‧GPS satellite

2a‧‧‧GPS satellite

2b‧‧‧GPS satellite

S1‧‧‧GPS positioning signal

Claims (14)

A GPS navigation system terminal device continuously provides a navigation screen for continuous navigation when traveling through a road surface having a traffic marking and cannot effectively receive a Global Positioning System (GPS) positioning information, the GPS navigation The system terminal device includes: a memory unit that pre-stores at least one map information; and an image capturing unit that captures a plurality of the traffic marking lines when the terminal device of the GPS navigation system passes the road surface having the traffic marking a road surface image; a timer for calculating, according to the road surface images, the terminal device of the GPS navigation system passing through the traffic marking line for one unit time; and a processing unit electrically connected to the memory unit, The image capturing unit and the timer calculate a traveling speed according to the road image and the unit time, and provide the navigation screen according to the map information and the traveling speed. The GPS navigation system terminal device of claim 1, wherein the processing unit calculates the traveling speed based on the road image and the unit time by an image computing module. The GPS navigation system terminal device of claim 2, wherein the image computing module comprises an image determination program. The GPS navigation system terminal device of claim 2, wherein the image computing module comprises a speed calculation program. The GPS navigation system terminal device of claim 1, wherein the traffic marking system comprises at least one solid line segment. The GPS navigation system terminal device according to claim 1, wherein the traffic marking line is a lane line. The GPS navigation system terminal device of claim 1, wherein the image capturing unit comprises a charge coupled device (CCD). The GPS navigation system terminal device according to claim 1, wherein the GPS positioning information is transmitted through a signal satisfying the International Marine Electronics Association 0183 (NMEA 0183) communication protocol. The GPS navigation system terminal device according to claim 1, further comprising a display unit for presenting the navigation screen. A speed calculation method for assisting navigation is to continuously provide a navigation screen for continuous navigation when passing through a road surface having a traffic marking and unable to effectively receive a Global Positioning System (GPS) positioning information. The method comprises the following steps: (a) pre-storing at least one map information; (b) extracting a plurality of road images covering the traffic marking when the terminal device of the GPS navigation system passes the road surface having the traffic marking; (c) Calculating a unit time of the user traveling through one of the unit line segments of the traffic marking line; (d) calculating a traveling speed according to the unit line segment displayed by the road surface image and the unit time; and (e) according to the map The information and the speed of travel generate the navigation screen. The speed calculation method for assisting navigation according to claim 10, wherein the traffic marking is a lane line. The speed calculation method for assisting navigation according to claim 10, wherein the step (c) further comprises a step (c0) of identifying at least one end point of the unit line segment in the road image, according to the The unit time is calculated from the start time and an end time. The speed calculation method for assisting navigation according to claim 10, wherein the step (d) further comprises the step (d0), wherein the unit line segment is defined according to the marking rule of the regional traffic sign length. The speed calculation method for assisting navigation according to claim 10, wherein the step (d) further comprises a step (d1) of defining a scale for the road image to be displayed from the road image. The displacement length of one of the unit line segments is calculated as the traveling speed.