CN106324633B

CN106324633B - System and method for tracking position and speed in GNSS application

Info

Publication number: CN106324633B
Application number: CN201510362470.7A
Authority: CN
Inventors: 斯科特·麦克法兰; 基思·格里菲斯; 里克·塞尔策
Original assignee: Radio Communication Systems
Current assignee: Radio Communication Systems
Priority date: 2015-06-26
Filing date: 2015-06-26
Publication date: 2022-07-05
Anticipated expiration: 2035-06-26
Also published as: CN106324633A

Abstract

The invention discloses a system and a method for tracking a moving object based on Global Navigation Satellite System (GNSS) data, comprising: detecting movement of the moving object with the motion detector independent of the GNSS data; receiving GNSS data by using a trusted position and speed unit, and determining a trusted position and a trusted speed of a moving object according to the GNSS position and speed, a detection result of a motion detector, and at least one of a GNSS scheme index, a GNSS signal index and a previous trusted position and speed or any combination thereof; and evaluating the trusted position and velocity of the moving object relative to the predetermined boundary with a boundary test unit.

Description

System and method for tracking position and speed in GNSS application

Technical Field

The present general inventive concept relates to an apparatus and method for tracking a moving object with respect to boundaries, and more particularly, to an apparatus and method for tracking a moving object with respect to boundaries using values of a plurality of different Global Navigation Satellite Systems (GNSS) and motion detectors.

Background

It is often desirable to monitor a moving object so that the moving object may be contained within a selected boundary and identify when the moving object leaves the boundary. A conventional method of monitoring the movement of a moving object and detecting whether the moving object has left a selected boundary or control area is to use a GNSS fencing system (GNSS fencing system).

Various conventional GNSS fence systems employing GNSS systems (e.g., Global Positioning System (GPS) in the united states, GLONASS in russia, etc.) are commonly used to define boundaries of a selected control area and to monitor movement of moving objects relative to the selected control area. In these systems, the position and velocity of a constrained moving object is monitored using GNSS satellites to determine if and when the moving object crosses a boundary. Typically, the boundary of the selected control area is programmed using a mobile device provided to the moving object as the mobile device moves along the boundary. Alternatively, the coordinates of the boundary vertices may be programmed directly into the mobile device. If a moving object provided with a mobile device crosses a boundary, a corrective stimulus may be provided to the moving object.

These conventional GNSS fencing systems typically employ differential GNSS to improve the perceived position and velocity of moving objects. This implementation improves the accuracy of determining the position of a moving object by incorporating pseudorange (or pseudorange) corrections to satellites observable at the position of the moving object, as compared to non-differential systems. As each satellite signal propagates to a receiver provided to the moving object, changes in the signal in the atmosphere or in the signal path cause these pseudorange errors to increase. Pseudorange corrections are computed by a stationary GNSS receiver at a known location and transmitted to the mobile object receiver over a suitable communication connection.

As described above, conventional GNSS position and velocity determination systems perform best in fence applications or boundary detection applications when a good signal environment is present. However, even in an optimal environment, anomalies in GNSS tracking still often occur. Furthermore, there may be a poor signal environment at the location of the moving object that is not present at the stationary GNSS receiver, and thus the signal environment cannot be identified as with a stationary GNSS receiver. Errors in determining position and velocity often cause false out-of-bounds in the presence of poor signal conditions. Such false cross-range can impair consumer confidence and/or can have negative psychological effects on moving objects such as: a mobile device is provided to the moving object to constrain its motion in the control region. For example, if the moving object is a pet (e.g., a dog) that may receive corrective incentives as a result of determining that a boundary has been crossed, then receiving corrective incentives when the control area boundary is not actually crossed may disrupt the training process.

Thus, to reduce the probability of false out-of-range decisions, there is a need for a mobile position determination device that: the mobile position determining device can identify, quantify and reduce position and velocity errors, especially in poor GNSS signal environments.

Disclosure of Invention

Embodiments of the present general inventive concept provide systems and methods to determine a trusted position and velocity of a moving object based on GNSS data.

Example embodiments of the present general inventive concept may be achieved by providing an apparatus to track a moving object based on Global Navigation Satellite System (GNSS) data, the apparatus including: a motion detector that detects motion of a moving object independent of GNSS data; and a trusted position and velocity determination unit that receives the GNSS data and determines a current trusted position and a current trusted velocity of the moving object.

The current trusted location may be a sum of a previous trusted location and a product of an attenuated location difference, which is a product of a location attenuation coefficient and a difference between the current GNSS location and the previous trusted location, and a location tracking coefficient, which may be a function of the trusted speed and the motion detected by the motion detector.

The current trusted speed may be a function of a previous trusted speed and an estimated value of an attenuation speed, the estimated value of the attenuation speed being a product of the estimated value of the speed and a speed attenuation coefficient, the estimated value of the speed being a function of the previous estimated value of the speed and the estimated value of the GNSS speed, the speed attenuation coefficient being a function of an indicator of the latest GNSS speed scenario and an indicator of the previous GNSS speed scenario, and the speed attenuation coefficient may be a function of an indicator of GNSS signals.

A boundary test unit may be provided to evaluate whether a boundary is crossed based on a current trusted position and a current trusted speed of the moving object relative to the predetermined boundary.

Furthermore, example embodiments of the present general inventive concept may be achieved by providing a method of tracking a moving object based on Global Navigation Satellite System (GNSS) data, the method including the steps of: detecting motion of the moving object independent of GNSS data with a motion detector; and receiving the GNSS data and determining a current trusted position and a current trusted speed of the moving object. In further embodiments, the current trusted location may be a sum of a previous trusted location and a product of an attenuated location difference and a location tracking coefficient, wherein the attenuated location difference is a product of a location attenuation coefficient and a difference of the current GNSS location and the previous trusted location, the location attenuation coefficient is a function of a latest GNSS location solution indicator and a GNSS signal indicator and the previous GNSS location solution indicator and the GNSS signal indicator, and the location tracking coefficient may be a function of a trusted speed and a motion detected by the motion detector.

The current trusted speed may be a function of a previous trusted speed and an estimate of a decay speed, where the estimate of the decay speed is a product of the estimate of the speed and a speed decay factor, the estimate of the speed is a function of the estimate of the previous speed and the estimate of the GNSS speed, the speed decay factor is a function of an indicator of the latest GNSS speed solution and an indicator of the previous GNSS speed solution, and the speed decay factor is a function of an indicator of GNSS signals. Whether a boundary is crossed may be evaluated based on a current trusted position and a current trusted speed of the mobile object relative to the predetermined boundary.

Example embodiments of the present general inventive concept may be achieved by an apparatus to track a moving object based on Global Navigation Satellite System (GNSS) data, the apparatus including: a motion detector that detects motion of a moving object independent of GNSS data; a trusted position and velocity determination unit that receives GNSS data and determines a trusted position and velocity of the moving object based on the GNSS position and velocity, the detection result of the motion detector, and at least one of a GNSS solution index, a GNSS signal index, and a previous trusted position and velocity, or any combination thereof; and a boundary test unit that evaluates a trusted position and velocity of the moving object relative to the predetermined boundary.

The GNSS solution indicators may include a horizontal precision factor, an estimated horizontal position error, an estimated velocity error, a horizontal precision factor times an estimated horizontal position error, a horizontal precision factor times an estimated velocity error, or any combination thereof.

The GNSS signal indicators may include a quantity representative of a total observable GNSS signal-to-noise ratio, where observable refers to all GNSS signals used to determine GNSS position and velocity, and/or a quantity representative of a total acceptable GNSS signal-to-noise ratio, where acceptable refers to all decodable GNSS signals emitted by satellites above a predetermined altitude threshold.

The motion detector may be a micro-electromechanical system (MEMS) device.

The motion detector may be an omni-directional vibration sensor.

A predetermined position within a control area may be used as an initial starting location of the moving object.

In response to the motion detector not detecting motion of the moving object, a previous trusted position and velocity may be maintained.

The GNSS data may include GNSS PVT (position, velocity, time) signals, pseudorange error data, time assistance data, ephemeris assistance data, or any combination thereof.

The moving object may be a human or an animal.

The device may be attached to or worn by a moving object.

Furthermore, example embodiments of the present general inventive concept may be achieved by a method of tracking a moving object based on Global Navigation Satellite System (GNSS) data, the method including the steps of: detecting motion of the moving object independent of GNSS data with a motion detector; receiving GNSS data by using a trusted position and speed determining unit, and determining a trusted position and speed of the moving object according to the GNSS position and speed, a detection result of the motion detector, and at least one of a GNSS scheme index, a GNSS signal index and a previous trusted position and speed or any combination thereof; and evaluating the trusted position and velocity of the moving object relative to the predetermined boundary with a boundary test unit.

The moving object may be a human or an animal.

Furthermore, example embodiments of the present general inventive concept may be also realized by a computer-readable storage medium having a program recorded thereon, the program causing a computer to execute a method of tracking a moving object to detect a boundary violation based on Global Navigation Satellite System (GNSS) data, the method comprising the steps of: detecting motion of the moving object independent of GNSS data with a motion detector; receiving GNSS data by using a trusted position and speed determining unit, and determining a trusted position and speed of the moving object according to the GNSS position and speed, a detection result of the motion detector, and at least one of a GNSS scheme index, a GNSS signal index and a previous trusted position and speed or any combination thereof; and evaluating the trusted position and velocity of the moving object relative to the predetermined boundary with a boundary test unit.

Furthermore, example embodiments of the present general inventive concept may be achieved by providing an apparatus to track a moving object based on Global Navigation Satellite System (GNSS) data, the apparatus including: a motion detector that detects motion of a moving object independent of GNSS data; a trusted position and velocity determination unit that receives GNSS data and determines a current trusted position and a current trusted velocity of the moving object, wherein the current trusted position is a sum of a product of a previous trusted position and an attenuated position difference that is a product of a position attenuation coefficient that is a function of a latest GNSS position solution indicator and a GNSS signal indicator and a previous GNSS position solution indicator and a GNSS signal indicator and a difference of the current GNSS position and the previous trusted position, and a position tracking coefficient that is a function of a trusted velocity and motion detected by the motion detector, and wherein the current trusted velocity is a function of a previous trusted velocity and an attenuated velocity estimate that is a product of a velocity estimate and a velocity attenuation coefficient, the velocity estimate being a function of the previous velocity estimate and the GNSS velocity estimate, the velocity attenuation coefficient is a function of the latest GNSS velocity profile indicator and the previous GNSS velocity profile indicator, and the velocity attenuation coefficient is a function of the GNSS signal indicator; and a boundary testing unit which evaluates whether the boundary is out of range according to the current credible position and the current credible speed of the mobile object relative to the preset boundary.

Drawings

The following exemplary embodiments illustrate exemplary techniques and structures designed to implement the present general inventive concept, but the present general inventive concept is not limited to these exemplary embodiments. The size and relative sizes, shapes and qualities of lines, individuals and regions may be exaggerated in the drawings and illustrations for clarity. Various additional embodiments will be more readily understood from the following detailed description of exemplary embodiments with reference to the following drawings, in which:

FIG. 1 illustrates a conventional differential GNSS system for determining mobile position and velocity;

FIG. 2 illustrates the determination of the position and velocity of a mobile device at discrete time intervals using a conventional differential GNSS system;

FIG. 3 illustrates a conventional mobile position and velocity determining apparatus;

fig. 4 shows a conventional mobile position and speed determining apparatus including a position maintaining unit;

fig. 5A through 5B illustrate a trusted location and velocity determination device according to an embodiment of the present general inventive concept;

FIG. 6 is a flowchart illustrating initializing a trusted location according to one embodiment of the present general inventive concept;

FIG. 7 illustrates a calculation of a position difference between a current GNSS position and a previous trusted position according to an embodiment of the present general inventive concept;

FIG. 8 illustrates a calculation of a short-term GNSS solution indicator based on HDOP and estimated horizontal position error, according to an embodiment of the present general inventive concept;

FIG. 9 is a flowchart illustrating calculation of an initial position decay factor and a long-term GNSS scheme index based on HDOP and estimated horizontal position error, according to an embodiment of the present general inventive concept;

FIG. 10 is a flowchart illustrating calculation of a subsequent position decay factor based on a long-term solution indicator and a constant characterizing a long-term poorly sustained position error threshold, according to one embodiment of the present general inventive concept;

FIG. 11 is a flowchart illustrating calculation of a subsequent location decay factor based on GNSS signal indicators, according to an embodiment of the present general inventive concept;

FIG. 12 is a flowchart illustrating defining a location decay factor according to one embodiment of the present general inventive concept;

fig. 13 illustrates a calculation of an attenuation position difference according to an embodiment of the present general inventive concept;

FIG. 14 illustrates a calculation of a short-term GNSS solution indicator based on HDOP and estimated velocity error, according to an embodiment of the present general inventive concept;

FIG. 15 is a flowchart illustrating calculation of an initial velocity decay factor and long-term GNSS scheme indicators based on HDOP and estimated velocity error, according to one embodiment of the present general inventive concept;

FIG. 16 is a flowchart illustrating calculation of a subsequent velocity decay factor based on a long-term scenario indicator and a constant characterizing a long-term poorly sustained velocity error threshold, according to one embodiment of the present general inventive concept;

FIG. 18 is a flowchart illustrating defining a velocity decay factor according to an embodiment of the present general inventive concept;

FIG. 19 is a flowchart illustrating a method for determining whether GNSS position and velocity are available or unavailable based on short-term GNSS solution indicators, according to an embodiment of the present general inventive concept;

fig. 20 illustrates a calculation of a velocity estimation value based on a moving object property according to an embodiment of the present general inventive concept;

FIG. 21 illustrates a calculation of a decay rate estimate according to an embodiment of the present general inventive concept;

FIG. 22 is a flowchart illustrating a calculation of a trusted speed based on GNSS positioning quality according to an embodiment of the present general inventive concept;

FIG. 23 is a flowchart illustrating testing a trusted speed for a minimum trusted speed constant and a result of a motion detector, according to one embodiment of the present general inventive concept;

FIG. 24 is a flowchart illustrating calculation of a new location tracking coefficient based on a trusted speed according to an embodiment of the present general inventive concept;

FIG. 25 is a flowchart illustrating computing a new trusted location based on available quality of position fixes, according to one embodiment of the present general inventive concept;

FIG. 26 illustrates a real path of a mobile device through a control area for use in a GNSS fence application;

FIG. 27 illustrates GNSS positions captured by the mobile device moving along the true path shown in FIG. 26; and

FIG. 28 illustrates trusted locations captured by the mobile device moving along the true path shown in FIG. 26.

Detailed Description

Various exemplary embodiments of the present general inventive concept will be described below with reference to the accompanying drawings and illustrations showing examples of embodiments. For the purpose of illustrating the general inventive concept, example embodiments are described herein with reference to the accompanying drawings.

The following detailed description is provided to assist the reader in a comprehensive understanding of the various methods, devices, and/or systems described herein. Accordingly, various changes, modifications, and equivalents of the various methods, devices, and/or systems described herein will be suggested to those skilled in the art. However, the described progress of the processing operation described is merely an example, the operation sequence is not limited thereto, and the operation sequence may be changed as is well known in the art, except for the operation that must be performed in a certain order. Moreover, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

A conventional differential GNSS system is shown in fig. 1. The plurality of satellites 11-1, 11-2, … … 11-N emit GNSS position velocity and time determining signals that are received by the mobile position and velocity determining means 12 provided to the mobile object and by the fixed position GNSS assistance and pseudorange error means 13. The mobile position and velocity determination device 12 also sends requests for GNSS assistance and pseudorange error data to the fixed position GNSS assistance and pseudorange error device 13 and the data is returned to the mobile position and velocity determination device 12 accordingly. Due to the fixed position of the GNSS assistance and pseudorange error means 13, anomalies due to atmospheric and signal path changes, etc. are readily identified so that corrected data can be transmitted to and used by the mobile position and velocity determination means 12.

In conventional GNSS fence systems, the control area is described by a set of vertices (i.e., latitude, longitude) and line segments (straight line segments, arcs, curves, etc.) connecting adjacent vertices. Since the system requires an operation to control the moving object within close proximity to the control area, the moving object is provided with the moving position and speed determining means 12. The device 12 is typically worn by the moving object or the device 12 is attached to the moving object using suitable means. As the moving object moves, the mobile position and velocity determination device 12 moves with it, GNSS position and velocity determinations are determined at discrete time intervals, determining a new position and new velocity of the moving object. The determined position and velocity are tested against one or more indicators or conditions that constitute an out-of-range with respect to the control area. Typically, the time interval for determining position and velocity is in the range of 250ms to 1 second.

Fig. 2 illustrates the determination of the position and velocity of a moving object at discrete time intervals using a conventional differential GNSS system. A portion of the control region is illustrated by vertices (a1, b1), (a2, b2), and (a3, b3) and line segments connecting these consecutive vertices, which define the boundaries of the control region. A boundary test is performed at an initial time (t) to determine the position and velocity of the mobile device provided to the moving object. Subsequent boundary tests are performed at times (t + Δ t), (t +2 Δ t), and (t +3 Δ t). As is visible from the last boundary test shown in fig. 2, it should be determined that the position of the moving object is outside the control area.

Conventional GNSS fencing systems employ one or more tests regarding the determined position and velocity of the mobile device to determine if an out-of-range of the control area has occurred. One typical test is: it is only determined whether the current location of the mobile device is within or outside the defined control area. Another typical test is to determine the shortest distance to the boundary. Yet another typical test is: based on the unit direction vector and the velocity, the shortest expected time to reach the boundary is determined. As shown in fig. 2, the determination of the position and velocity of the mobile device at time (t +2 Δ t) will likely generate a direction vector that indicates an impending boundary crossing.

Fig. 3 shows a conventional mobile position and speed determining device 30. The signal reception and correction unit 31 receives GNSS PVT (position, velocity, time) determination signals at time (t + N Δ t) from a certain number of GNSS satellites. The signal reception and correction unit 31 also receives GNSS assistance data in the form of pseudorange error data from fixed position GNSS assistance and pseudorange error devices. After correcting each received satellite signal according to the pseudo-range error data, the signal reception and correction unit 31 transmits the resultant data to the PVT engine 32. The PVT engine 32 receives the corrected data and the additional GNSS assistance data in the form of time assistance and ephemeris assistance data from the signal reception and correction unit 31 and determines the position Pos (t + N Δ t) and velocity Spd (t + N Δ t) of the mobile position and velocity determination apparatus 30 at the time t + N Δ t. The PVT engine 32 transmits the position Pos (t + N Δ t) to the delay element 33, the unit direction vector calculator 34, and the boundary test unit 35. The delay element 33 introduces a delay d to the position Pos (t + N Δ t) to generate a delay position Pos (t + (N-d) Δ t) and transmits it to the unit direction vector calculator 34. The unit direction vector calculator 34 receives the position Pos (t + N Δ t) and the delay position Pos (t + (N-d) Δ t), and determines a unit direction vector U _ vector (t + N Δ t) transmitted to the boundary test unit 35. Further, the boundary test unit 35 receives the speed Spd (t + N Δ t) from the PVT engine 32.

Further, the boundary test unit 35 receives the boundary vertices (a1, b1), (a2, b2), … … (aN, bN) of the control region from the boundary vertex storage unit 36. The boundary test unit 35 determines using the received boundary vertices, the velocity Spd (t + N Δ t), the position Pos (t + N Δ t), and the unit direction vector U _ vector (t + N Δ t): whether the mobile position and speed determination device 30 is currently located within the control area; the shortest distance from device 30 to the control area boundary; and the shortest expected time to reach the boundary. As shown in fig. 3, the boundary test unit 35 outputs these determination results as: In/Out _ test (t + N Δ t), Distance _ test (t + N Δ t), and Time _ test (t + N Δ t). These resulting signals may be used to trigger an excitation from the device 30.

In general, conventional differential GNSS fencing systems operate more regularly in such situations: a mobile device receiving GNSS signals operates in a good GNSS signal environment. However, the determination of differential GNSS position and velocity still contains substantial and unresolvable errors, particularly in the presence of common signal impairments, such as when the mobile device has moved inside a home or other structure, the mobile device is covered by thick foliage, and the like. Although conventional differential GNSS systems are an improvement over non-differential GNSS systems, conventional differential GNSS systems still cannot adequately correct for these common signal impairments and the result is often a false out-of-range decision.

A conventional improvement to typical differential GNSS fencing systems is a "position keeping" operation. The position-keeping algorithm will "keep" the GNSS position (keep the GNSS position unchanged) when there is not enough change in position and velocity. The goal of developing location-keeping techniques is to eliminate drift in GNSS location determination when the mobile device is stationary. When sufficient change in position or velocity is detected, the position maintenance algorithm is bypassed.

Fig. 4 shows a conventional mobile position and speed determining apparatus 40, which includes a position holding unit 41. As shown in fig. 4, the device 40 is similar to the device 30 shown in fig. 3, with the addition of a position holding unit 41. The PVT engine 32 controls the position maintenance unit 41 such that it is bypassed when sufficient position change or velocity is detected.

As previously described, the addition of a position keeping unit to the mobile position and velocity determination device 40 helps maintain an almost constant GNSS position for the mobile device when the mobile device is not moving. Thus, potentially irregular portions of the position determination may be avoided when the mobile device is stationary. However, this improvement does not help to reduce the effects of the common GNSS signal corruption described above when the mobile device is moving.

Fig. 5A-5B illustrate a trusted GNSS position and velocity determination apparatus 50 according to one embodiment of the present general inventive concept. Each of fig. 5A-5B shows portions of this example apparatus separated by the cut lines shown. The trusted location and speed determining apparatus 50 may be interchangeably referred to herein as a "mobile device".

It is to be noted that the apparatus of fig. 5A to 5B is only one exemplary embodiment of the present general inventive concept. There are many different possible physical configurations for implementing the illustrated embodiments. For example, two or more units may be combined in a single integrated circuit chip, two or more integrated circuit chips may be combined in one or more chipsets, and so forth. Additionally, some or all of the described operations may be performed and/or controlled by software, and various different described units, elements, etc. may be functional blocks of the software. Such software may be executed by a computer, machine, processor, or the like, using input-output processing that produces the described results, which may be provided to device 50, or may be provided as device 50.

The mobile device 50 may be provided in a fixed or removably attachable manner to any number of possible mobile objects. The moving object may be a human, an animal, a machine, or the like. For example, to confine the dog within a defined area (e.g., the yard of a residence in which the dog owner resides), the mobile device 50 may be affixed to a collar of the dog worn by the dog. This is merely a non-limiting example of how the mobile device 50 may be used.

The trusted position and velocity determination apparatus 50 (or mobile device 50) derives a "trusted" position and velocity of a mobile object, which is used for the following applications: such as GNSS fencing, boundary detection, control (containment), etc. Trusted location refers to a location that: it relies on more accurate position and velocity determination than GNSS-derived position and velocity alone. The trusted position and velocity are quantities derived from the GNSS position and velocity, the confirmation of movement of the mobile device 50 from the independent motion detector, and one or more of the GNSS signal indicators, the GNSS solution indicators, and the previously determined trusted speed and position. In a good signal environment, the trusted position and velocity can track GNSS position and velocity very closely at a confirmed moderate velocity. However, as the GNSS signal environment deteriorates or the GNSS speed decreases, the trusted position and speed track the GNSS position and speed less closely. In the event that the GNSS signal environment and/or GNSS velocity are below acceptable levels, the trusted speed and position may stop tracking GNSS position and velocity altogether. The determination of the trusted location and velocity makes the probability of false out-of-bounds decisions much lower.

Furthermore, practical energy constraints often require the mobile device to conserve energy whenever possible. For example, if the moving object (and consequently the mobile device 50) is not in close proximity to any boundary segment of the control area and is stationary (as confirmed by the aforementioned independent motion detector), the mobile device 50 may get an opportunity to save energy by stopping the GNSS navigation. At a later point in time, when the independent motion detector detects motion of the moving object, the trusted location may be initialized to a location (location) based on the conditions that existed when the previous navigation stopped. If the moving object is within the control area or in close proximity to the boundary of the control area, the trusted location may be initialized to a known location (or "reliable start point") within the control area. The owner or operator of the mobile device 50 may determine a reliable starting location at his or her discretion, which will be described in more detail below. Otherwise, if the mobile object is not in close proximity to the boundary of the control area, the trusted location may be initialized with the last known trusted location. When the navigation is resumed, a fast "first fix time" is maintained by means of the relevant assistance data provided by means of, for example, an RF communication connection. Regardless of the navigation state of the mobile device 50, there is assistance data available to the mobile device 50 because the stationary "reference" GNSS receiver can maintain and make available accurate time, pseudorange corrections, ephemeris data, and ion correction models.

It is noted that the inclusion of a separate motion detector merely means that the detection of motion is not dependent on the processing of GNSS signals received by the mobile device 50. According to various embodiments, the independent motion detector may be a separately formed device provided to the mobile device 50 or a device integrated with the mobile device 50.

Referring to the exemplary embodiments of the present general inventive concept illustrated in fig. 5A through 5B, the trusted GNSS position and speed determination device 50 includes: a signal receiving and correcting unit 51, a PVT engine 52, a trusted position and velocity determining unit 53, first and second low-pass filters 54-1 and 54-2, an independent motion detector 55, first and second delay elements 56-1 and 56-2, a unit direction vector calculating unit 57, a boundary testing unit 58, and a boundary vertex storing unit 59. Various other example embodiments of the present general inventive concept may include more or less elements than those shown in the discussion regarding this example. Some or all of the described operations may be performed and/or controlled by software, and various different units, elements, etc. described may be functional blocks of the software.

The signal reception and correction unit 51 receives GNSS PVT (position, velocity, time) determination signals at time (t + N Δ t) from a certain number of GNSS satellites. The signal receiving and correcting unit 51 may have an integrated receiver for directly receiving the signal, or may receive the signal from another receiver (not shown). The signal reception and correction unit 51 also receives GNSS assistance data in the form of pseudorange error data from fixed position GNSS assistance and pseudorange error devices or similar devices for delivering GNSS assistance data. After correcting the received satellite signals according to the pseudo-range error data (discussed in more detail later below), the signal reception and correction unit 51 transmits the resultant data to the PVT engine 52. The signal receiving and correcting unit 51 also transmits the corrected signal to the first low-pass filter 54-1 and the second low-pass filter 54-2.

The PVT engine 52 receives the corrected data and additional GNSS assistance data in the form of time assistance and ephemeris assistance data from the signal reception and correction unit 51 and generates a GNSS position, a GNSS velocity and several GNSS solution indices, which are transmitted to the trusted position and velocity determination unit 53. The processing of these several signals will be discussed in more detail later below.

The GNSS solution metrics processed and transmitted by the PVT engine 52 include: horizontal dilution of precision (HDOP) Hor _ DOP (t + N Δ t), estimated horizontal position error Est _ Hor _ Pos _ Err (t + N Δ t), and estimated velocity error Est _ Spd _ Err (t + N Δ t). In the figure, the GNSS position is represented by Pos (t + N Δ t) and the GNSS velocity is represented by Spd (t + N Δ t).

The first low-pass filter 54-1 and the second low-pass filter 54-2 process the data received from the signal reception and correction unit 51 and respectively calculate and transmit to the trusted position and velocity determination unit 53 an index of the average observable signal-to-noise ratio Ave _ Obs _ SNR (t + N Δ t), which is a quantity representing the GNSS signal-to-noise ratio of the total observable (all used GNSS signals); and an average qualifying signal-to-noise ratio Ave _ Eli _ SNR (t + N Δ t), which is a quantity of GNSS signal-to-noise ratios that represents the total qualifying (all decodable GNSS signals emitted by satellites above a predetermined altitude threshold). At each epoch (i.e., Δ t), a new Ave _ Obs _ SNR (t + N Δ t) and a new Ave _ Eli _ SNR (t + N Δ t) are calculated. Both of which are fed to a first low pass filter 54-1 and a second low pass filter 54-2. The first low pass filter 54-1 and the second low pass filter 54-2 function to allow slow increase and rapid decrease of each average. The time constant of this increase may be of the order of 15 x Δ t. The average observable signal-to-noise ratio and the average qualified signal-to-noise ratio are referred to as the GNSS signal indicators.

The trusted position and velocity determination unit 53 receives the horizontal accuracy factor, the estimated horizontal position error, the estimated velocity error, the GNSS position, the GNSS velocity, the average observable signal-to-noise ratio, the average qualified signal-to-noise ratio, and the previous trusted position and velocity, and processes the trusted position Act _ Pos (t + N Δ t) and the trusted velocity Act _ Spd (t + N Δ t) accordingly. Furthermore, the trusted position and velocity determination unit 53 receives acknowledgement signals from the independent motion detector 55 to determine how to process the trusted position and velocity. The processing of this data is discussed in more detail later herein.

The trusted position and velocity determination unit 53 transmits the trusted position to the first delay element 56-1, the unit direction vector calculation unit 57, and the boundary test unit 58. The first delay element 56-1 introduces a delay d to the trusted location to generate and transmit a delayed trusted location Act _ Pos (t + (N-d) Δ t) to the unit direction vector calculation unit 57. In addition, the delayed trusted location is returned to the trusted location and speed determination unit 53. The unit direction Vector calculation unit 57 receives the trusted position and the delayed trusted position and generates a unit direction Vector U _ Vector (t + N Δ t), which is then transmitted to the boundary test unit 58.

The trusted position and velocity determination unit 53 transmits the trusted velocity to the second delay element 56-2 and the boundary test unit 58. The second delay element 56-2 introduces a delay d to the trusted speed to generate and transmit a delayed trusted speed Act _ Spd (t + (N-d) Δ t) back to the trusted position and speed determination unit 53.

Boundary test unit 58 receives the unit direction vector, the trusted position, the trusted speed, and a signal indicating whether a GNSS position and speed fix is available. The location quality signal is transmitted from the trusted position and velocity determination unit 53 to the boundary test unit 58. The boundary test unit 58 also receives boundary vertices (a1, b1), (a2, b2), … … (aN, bN) of the control area from the boundary vertex storage unit 59. The boundary test unit 58 uses the received boundary vertices, trusted locations, trusted speeds, unit direction vectors, and positioning quality to generate data indicating whether the current mobile device 50 is within or outside the control area, the shortest distance from the mobile device 50 to the boundary of the control area, and the shortest expected time to reach the boundary. As shown In fig. 5B, the boundary test unit 58 outputs these determination results as In/Out _ test (t + N Δ t), Distance _ test (t + N Δ t), and Time _ test (t + N Δ t). These resulting signals may be used to trigger an excitation (not shown) that is provided to the device 50 or communicated to the device 50. The processing of this data is explained in more detail later below.

A number of different operations performed according to many different embodiments of the present general inventive concept will be described below.

Fig. 6 is a flowchart illustrating initializing a trusted location according to an embodiment of the present general inventive concept. After the navigation process is initiated for the first time using the mobile device 50, the reliable start location is set to the last known trusted location in operation 61. If the mobile device 50 is undergoing a reboot or reset resulting from the detected motion, rather than being booted for the first time, the last known trusted location has been stored.

In operation 62, it is determined whether the last known trusted location is within the control zone proximity threshold. If it is determined that the last known trusted location is within the proximity threshold, the reliable start location is set to the trusted location Act _ Pos (t) in operation 63. If it is determined that the last known trusted location is not within the proximity threshold, the last known trusted location is set to the trusted location Act _ Pos (t) in operation 64.

Fig. 7 illustrates a calculation of a position difference Pos _ Dif (t + N Δ t) between a current GNSS position GNSS _ Pos (t + N Δ t) and a previous trusted position Act _ Pos (t + (N-1) Δ t), according to an embodiment of the present general inventive concept. The position difference Pos _ Dif (t + N Δ t) calculated in the difference calculation unit 71 may be used as described in the subsequent operation.

FIG. 8 illustrates a calculation of a short-term GNSS solution indicator based on HDOP and estimated horizontal position error, according to an embodiment of the present general inventive concept. This calculation may be performed in the trusted position and velocity determination unit 53 of the mobile device 50. As shown in fig. 8, the horizontal precision factor (HDOP) Hor _ DOP (t + N Δ t) and the estimated horizontal position error Est _ Hor _ Pos _ Err (t + N Δ t) are input to an error location unit 81 to generate an HDOP error location HDOP _ Err _ Pos (t + N Δ t). The short-term filter 82 receives the HDOP error position HDOP _ Err _ Pos (t + N Δ t) and the delayed short-term HDOP error position ST _ HDOP _ Err _ Pos (t + (N-1) Δ t) sent back from the delay element 84 to generate and output a short-term HDOP error position ST _ HDOP _ Err _ Pos (t + N Δ t). In addition, the output short-term HDOP error position ST _ HDOP _ Err _ Pos (t + N Δ t) is received by the delay element 83 and used to generate a delayed short-term HDOP error position ST _ HDOP _ Err _ Pos (t + (N-1) Δ t). The short-term time constant may be of the order of 3 x Δ t.

Fig. 9 is a flowchart illustrating calculation of an initial position decay factor and a long-term GNSS solution indicator according to an embodiment of the present general inventive concept. In operation 91, it is determined whether the short-term HDOP error position ST _ HDOP _ Err _ Pos (t + N Δ t) is greater than the delayed long-term HDOP error position LT _ HDOP _ Err _ Pos (t + (N-1) Δ t). If the short-term HDOP error position is greater than the delayed long-term HDOP error position, operation 92 is performed in which the short-term HDOP error position and the delayed long-term HDOP error position are input to a Sqrt (LT/ST) unit 94, which generates and outputs an initial position decay factor Pos _ Deg (t + N Δ t). In addition, the short-term HDOP error position and the delayed long-term HDOP error position LT _ HDOP _ Err _ Pos (t + (N-1) Δ t) are received by a long-term filter 96 that generates the long-term HDOP error position LT _ HDOP _ Err _ Pos (t + N Δ t). The long-term HDOP error position is also fed into a delay element 98, which generates a delayed long-term HDOP error position LT _ HDOP _ Err _ Pos (t + (N-1) Δ t) and feeds it into the long-term filter 96. The long-term time constant may be of the order of 20 x Δ t.

If the short-term HDOP error position is not greater than the delayed long-term HDOP error position, the long-term HDOP error position LT _ HDOP _ Err _ Pos (t + N Δ t) is set equal to the short-term HDOP error position and the position attenuation factor Pos _ Deg (t + N Δ t) is set equal to 0.5 Pos _ Deg (t + (N-1) Δ t) +0.5, where Pos _ Deg (t + (N-1) Δ t) is the delayed position attenuation factor or the final position attenuation factor in operation 93.

Fig. 10 is a flowchart illustrating calculation of a subsequent position decay factor based on a long-term scenario indicator and a constant characterizing a long-term position error threshold that is continuously poor according to one embodiment of the present general inventive concept. In operation 101, it is determined whether the long-term HDOP error position LT _ HDOP _ Err _ Pos (t + N Δ t) is greater than a constant LT _ threshold that characterizes a continuously poor long-term position error threshold. If the long-term HDOP error position is greater than LT _ threshold, then the subsequent position decay factor Pos _ Deg (t + N Δ t) is multiplied by LT _ threshold divided by the long-term HDOP error position in operation 102.

Fig. 11 is a flowchart illustrating calculation of a subsequent location decay factor based on GNSS signal indicators, according to an embodiment of the present general inventive concept. It is determined in operation 110 whether the average observable signal-to-noise ratio Ave _ Obs _ SNR (t + N Δ t), which is a quantity representing the GNSS signal-to-noise ratio of the total observable (all used GNSS signals), is greater than the average qualifying signal-to-noise ratio Ave _ Eli _ SNR (t + N Δ t), which is a quantity representing the GNSS signal-to-noise ratio of the total qualifying (all decodable GNSS signals emitted by satellites above a predetermined altitude threshold). If the average observable signal-to-noise ratio is greater than the average acceptable signal-to-noise ratio, then the subsequent position attenuation factor Pos _ Deg (t + N Δ t) is multiplied by the quotient of the average acceptable signal-to-noise ratio divided by the average observable signal-to-noise ratio in operation 120.

Further, it is determined in operation 112 whether the average observable signal-to-noise ratio is less than or equal to the low SNR threshold. If the average observable signal-to-noise ratio is less than or equal to the low SNR threshold, then the subsequent position attenuation factor Pos _ Deg (t + N Δ t) is multiplied by a constant k in operation 113, where k is a constant less than 1.

Fig. 12 is a flowchart illustrating defining a location attenuation factor according to an embodiment of the present general inventive concept. In operation 120, it is determined whether the last known trusted location Act _ Pos (t + (N-1) Δ t) and the last known trusted speed Act _ Spd (t + (N-1) Δ t) resulted in an out-of-range. If it is determined that the out-of-bounds does occur, it is determined whether the position attenuation factor Pos _ Deg (t + N Δ t) is less than the minimum position attenuation factor posgradient in operation 121. If the location attenuation factor is less than the minimum location attenuation factor, the location attenuation factor is set equal to the minimum location attenuation factor in operation 122.

Fig. 13 illustrates a calculation of an attenuation position difference according to an embodiment of the present general inventive concept. Both the position difference Pos _ Dif (t + N Δ t) and the position attenuation factor Pos _ Deg (t + N Δ t) are received by the attenuation position difference calculation unit 131, and then the attenuation position difference calculation unit 131 generates and outputs an attenuation position difference Deg _ Pos _ Dif (t + N Δ t).

FIG. 14 illustrates a calculation of a short-term GNSS solution indicator based on HDOP and estimated velocity error, according to an embodiment of the present general inventive concept. This calculation may be performed in the trusted position and velocity determination unit 53 of the mobile device 50. As shown in fig. 14, the horizontal precision factor (HDOP) Hor _ DOP (t + N Δ t) and the estimated speed error Est _ Spd _ Err (t + N Δ t) are input to the HDOP error speed unit 141 to generate the HDOP error speed HDOP _ Err _ Spd (t + N Δ t). The short-term filter 142 receives the HDOP error rate HDOP _ Err _ Spd (t + N Δ t) and the delayed short-term HDOP error rate ST _ HDOP _ Err _ Spd (t + (N-1) Δ t) sent back from the delay element 143 to generate and output the short-term HDOP error rate ST _ HDOP _ Err _ Spd (t + N Δ t). In addition, the output short-term HDOP error rate ST _ HDOP _ Err _ Spd (t + N Δ t) is received by the delay element 143 and used to generate the delayed short-term HDOP error rate ST _ HDOP _ Err _ Spd (t + (N-1) Δ t). The short-term time constant may be of the order of 3 x Δ t.

Fig. 15 is a flowchart illustrating calculation of an initial velocity decay factor and a long-term GNSS solution indicator based on HDOP and estimated velocity error according to an embodiment of the present general inventive concept. In operation 151, it is determined whether the short-term HDOP error rate ST _ HDOP _ Err _ Spd (t + N Δ t) is greater than the delayed long-term HDOP error rate LT _ HDOP _ Err _ Spd (t + (N-1) Δ t). If the short-term HDOP error rate is greater than the delayed long-term HDOP error rate, operation 152 is performed, wherein the short-term error rate and the delayed long-term HDOP error rate are input to Sqrt (LT/ST) unit 153, which generates and outputs a rate attenuation factor Spd _ Deg (t + N Δ t). In addition, the short-term HDOP error rate and the delayed long-term HDOP error rate are received by a long-term filter 154 that generates a long-term HDOP error rate LT _ HDOP _ Err _ Spd (t + N Δ t). In addition, the long-term HDOP error rate is sent back to the delay element 155, which generates and transmits a delayed long-term HDOP error rate LT _ HDOP _ Err _ Spd (t + (N-1) Δ t) to the long-term filter 154. The long-term time constant may be of the order of 20 x Δ t.

If the short-term HDOP error rate is not greater than the delayed long-term HDOP error rate, then the long-term HDOP error rate LT _ HDOP _ Err _ Spd (t + N Δ t) is set equal to the short-term HDOP error rate in operation 156 and the speed decay factor Spd _ Deg (t + N Δ t) is set equal to 0.5 Spd _ Deg (t + (N-1) Δ t) +0.5, where Spd _ Deg (t + (N-1) Δ t) is the delayed speed decay factor or the previous speed decay factor.

Fig. 16 is a flowchart illustrating calculation of a subsequent velocity decay factor based on a long-term scenario indicator and a constant characterizing a long-term poorly sustained velocity error threshold according to an embodiment of the present general inventive concept. In operation 161 it is determined whether the long-term HDOP error speed LT _ HDOP _ Err _ Spd (t + N Δ t) is greater than a constant LT _ threshold that characterizes a continuously poor long-term speed error threshold. If the long-term HDOP error rate is greater than LT _ threshold, then the subsequent rate decay factor Spd _ Deg (t + N Δ t) is multiplied by the quotient of LT _ threshold divided by the long-term HDOP error rate in operation 162.

Fig. 17 is a flowchart illustrating calculation of a subsequent velocity decay factor based on GNSS signal indicators, according to an embodiment of the present general inventive concept. It is determined in operation 171 whether the average observable signal-to-noise ratio Ave _ Obs _ SNR (t + N Δ t), which is a quantity representing the GNSS signal-to-noise ratio of the total observable (all used GNSS signals), is greater than the average qualifying signal-to-noise ratio Ave _ Eli _ SNR (t + N Δ t), which is a quantity representing the GNSS signal-to-noise ratio of the total qualifying (all decodable GNSS signals emitted by satellites above a predetermined altitude threshold). If the average observable signal-to-noise ratio is greater than the average acceptable signal-to-noise ratio, then the subsequent velocity decay factor Spd _ Deg (t + N Δ t) is multiplied by the quotient of the average acceptable signal-to-noise ratio divided by the average observable signal-to-noise ratio in operation 172.

Further, it is determined in operation 173 whether the average observable signal-to-noise ratio is less than or equal to the low SNR threshold. If the average observable signal-to-noise ratio is less than or equal to the low SNR threshold, then the subsequent velocity decay factor Spd _ Deg (t + N Δ t) is multiplied by a constant k in operation 174, where k is a constant less than 1.

Fig. 18 is a flowchart illustrating defining a velocity decay factor according to an embodiment of the present general inventive concept. In operation 181, it is determined whether the last known trusted location Act _ Pos (t + (N-1) Δ t) and the last known trusted speed Act _ Spd (t + (N-1) Δ t) resulted in an out-of-range. If it is determined that an out-of-range event does occur, a determination is made in operation 182 whether the speed decay factor Spd _ Deg (t + N Δ t) is less than the minimum speed decay factor speedDegrade. If the velocity decay factor is less than the minimum velocity decay factor, the velocity decay factor is set equal to the minimum velocity decay factor in operation 183.

Fig. 19 is a flowchart illustrating a determination of whether a GNSS position and velocity are available or unavailable based on short-term GNSS scheme indicators according to an embodiment of the present general inventive concept. In operation 191, it is determined whether the short-term HDOP error position ST _ HDOP _ Err _ Pos (t + N Δ t) is greater than the maximum acceptable short-term position error ST _ Pos _ Err. If the short-term HDOP error position is not greater than the maximum acceptable short-term position error, a determination is made in operation 192 as to whether the short-term HDOP error speed ST _ HDOP _ Err _ Spd (t + N Δ t) is greater than the maximum acceptable short-term speed error ST _ Spd _ Err. The GNSS position and velocity or position fix is determined to be available if the short-term HDOP error velocity is not greater than the maximum acceptable short-term velocity error. The above behavior is indicated in operation 193, in which the positioning quality fix quality (t + N Δ t) is made available.

If the short-term HDOP error position is greater than the maximum acceptable short-term position error, or the short-term HDOP error velocity is greater than the maximum acceptable short-term velocity error, then the quality of the position fix is determined to be unavailable in operation 194.

Fig. 20 illustrates calculation of a velocity estimation value based on various properties of a moving object according to an embodiment of the present general inventive concept. As shown, the GNSS velocity GNSS _ Spd (t + N Δ t) and the delayed velocity estimate Spd _ Est (t + (N-1) Δ t) are received by the acceleration limiter and filter 200, which then generates the velocity estimate Spd _ Est (t + N Δ t) based on various attributes of the moving object. These attributes may be entered into the mobile device 50 by the user. The various attributes may include information about such things as known physical properties, type of moving object (e.g., dog, cow, human, etc.).

Fig. 21 illustrates a calculation of a decay rate estimate according to an embodiment of the present general inventive concept. As shown, the speed decay factor Spd _ Deg (t + N Δ t) and the speed estimate Spd _ Est (t + N Δ t) are received by the decay speed estimation unit 210, and the decay speed estimation unit 210 generates the decay speed estimate Deg _ Spd _ Est (t + N Δ t) accordingly.

Fig. 22 is a flowchart illustrating a calculation of a trusted speed based on GNSS positioning quality according to an embodiment of the present general inventive concept. In operation 221, it is determined whether a value of the positioning quality fix quality (t + N Δ t) is available. If the quality of the fix is not available, the trusted speed Act _ Spd (t + N Δ t) is attenuated toward zero, as shown in operation 222, where the trusted speed Act _ Spd (t + N Δ t) is set equal to the delayed trusted speed Act _ Spd (t + (N-1) Δ t) multiplied by an attenuation factor. If location quality is available, then it is determined whether the delayed trusted location Act _ Pos (t + (N-1) Δ t) and the delayed trusted speed Act _ Spd (t + (N-1) Δ t) are out of bounds in operation 223. As shown, the average observable signal-to-noise ratio Ave _ Obs _ SNR (t + N Δ t), the decay velocity estimate Deg _ Spd _ Est (t + N Δ t), the delayed confidence velocity Act _ Spd (t + (N-1) Δ t), and the determination of whether the last confidence position and velocity resulted in a boundary crossing are input to confidence velocity calculation unit 225, which generates confidence velocity Act _ Spd (t + N Δ t). In addition, the trusted speed output by the trusted speed calculation unit 225 is also sent back to the delay element 226 that generates the delayed trusted speed Act _ Spd (t + (N-1) Δ t).

Fig. 23 is a flowchart illustrating a test of a trusted speed for a minimum trusted speed constant and a result of a motion detector according to an embodiment of the present general inventive concept. In operation 231, it is determined whether the trusted speed Act _ Spd (t + N Δ t) is greater than a minimum trusted speed constant. If it is determined that the trusted speed is greater than the constant, then it is determined whether the independent motion detector confirms movement of the mobile device in operation 232. If it is determined that there is no movement confirmed by the independent motion detector, it is determined that there is no actual motion and speed of the mobile device in operation 234 and the value of motionextended speed is set to false. If it is determined that there is movement confirmed by the independent motion detector, the value of motionextended speed is set to true in operation 233. If Act _ Spd (t + N Δ t) is determined to be less than the minimum trusted speed in operation 231, the value of motionSpeed is set to false in operation 234.

Fig. 24 is a flowchart illustrating calculation of a new location tracking coefficient based on a trusted speed according to an embodiment of the present general inventive concept. In operation 241, it is determined whether the motion compared is set to true. In other words, it is determined whether the motion and velocity of the mobile device are all present. If the value of motionextended speed is true, then the new position tracking coefficient Pos _ Tra _ Coe (t + N Δ t) is set equal to the product of m and the natural logarithm of the trusted speed Act _ Spd (t + N Δ t) plus b in operation 242. Variables m and b are set according to each attribute of the object. In this embodiment of the present general inventive concept, the position tracking coefficient Pos _ Tra _ Coe (t + N Δ t) is linear with the natural logarithm of the trusted speed Act _ Spd (t + N Δ t). If the value of motionextended speed is not true, then the position tracking coefficient is allowed to decay in operation 243, in which the position tracking coefficient is multiplied by the tracking coefficient decay value.

Furthermore, example embodiments of the present general inventive concept may be achieved by providing an apparatus to track a moving object based on Global Navigation Satellite System (GNSS) data, the apparatus including a motion detector to detect a motion of the moving object without depending on the GNSS data; and a trusted position and velocity determination unit for receiving GNSS data and determining a current trusted position and a current trusted velocity of the moving object.

Example embodiments of the present general inventive concept may also be implemented by various systems, methods, and computer-readable media: wherein the current trusted location may be a sum of a prior trusted location and a product of an attenuated location difference and a location tracking coefficient, wherein the attenuated location difference is a product of a location attenuation coefficient and a difference between the current GNSS location and the prior trusted location, the location attenuation coefficient is a function of a latest GNSS location solution indicator and a GNSS signal indicator and a prior GNSS location solution indicator and a GNSS signal indicator, and the location tracking coefficient may be a function of a trusted speed and a motion detected by the motion detector; also, the current trusted speed may be a function of a prior trusted speed and an estimated value of a fading speed, where the estimated value of the fading speed is a product of the estimated value of the speed and a speed fading coefficient, the estimated value of the speed is a function of the prior estimated value of the speed and the estimated value of the GNSS speed, the speed fading coefficient is a function of the latest GNSS speed plan index and the prior GNSS speed plan index, and the speed fading coefficient may be a function of the GNSS signal index.

Further, embodiments of the present general inventive concept can be achieved by providing a method of tracking a moving object based on Global Navigation Satellite System (GNSS) data, the method including the steps of: the method further comprises detecting the motion of the moving object with a motion detector independent of the GNSS data, and receiving the GNSS data and determining a current trusted position and a current trusted speed of the moving object. In further embodiments, the current trusted location may be a sum of a previous trusted location and a product of an attenuated location difference and a location tracking coefficient, wherein the attenuated location difference is a product of a location attenuation coefficient and a difference of the current GNSS location and the previous trusted location, the location attenuation coefficient is a function of a latest GNSS location solution indicator and GNSS signal indicators and a previous GNSS location solution indicator and GNSS signal indicators, and the location tracking coefficient may be a function of a trusted speed and motion detected by the motion detector.

The current trusted speed may be a function of a previous trusted speed and an estimate of a decay speed, where the estimate of the decay speed is a product of the estimate of the speed and a speed decay factor, the estimate of the speed is a function of the estimate of the previous speed and the estimate of the GNSS speed, the speed decay factor is a function of an indicator of the latest GNSS speed solution and an indicator of the previous GNSS speed solution, and the speed decay factor is a function of an indicator of GNSS signals. Whether a boundary is out-of-range may be assessed based on a current trusted location and a current trusted speed of the mobile object relative to a predetermined boundary.

The lower limit of the location decay factor may be set by determining whether the previous trusted location and speed resulted in a boundary violation.

In some embodiments, the lower limit of the velocity decay factor may be set by determining whether the previous trusted location and velocity resulted in a boundary violation. The current trusted speed may be another function of the GNSS solution indicator and/or whether the previous trusted position and speed resulted in a boundary crossing.

Fig. 25 is a flowchart illustrating calculation of a new trusted location based on available quality of location according to an embodiment of the present general inventive concept. In operation 251, it is determined whether positioning quality has been set as available. If it is determined that the quality of the positioning has not been set as available, the trusted location Act _ Pos (t + N Δ t) is set to the trusted location Act _ Pos (t + (N-1) Δ t) equal to the delay in operation 252. If it is determined that the quality of the position fix has been set as available, the trusted location is set in a new manner in operation 253. In operation 253, the position tracking coefficients Pos _ Tra _ Coe (t + N Δ t), the attenuated position difference Deg _ Pos _ Dif (t + N Δ t), and the delayed trusted position Act _ Pos (t + (N-1) Δ t) are input to trusted position unit 256 to generate a trusted position Act _ Pos (t + N Δ t), which is sent back to delay unit 257 to generate a delayed trusted position Act _ Pos (t + (N-1) Δ t).

Fig. 26 to 28 show experimental results of a tracking and boundary crossing test using one embodiment of the present general inventive concept, compared to using only GNSS signals.

FIG. 26 illustrates an actual known path of a mobile device through a control area for use in a GNSS fence application. The fence is represented by solid lines 261 connecting variably spaced vertices 262 and surrounding the illustrated house. A mobile device configured in accordance with one embodiment of the present invention moves back and forth along the solid bold line 263 shown while recording both GNSS and trusted locations under the same environment. The test lasts about five minutes, recording over four hundred GNSS positions and trusted positions. The encircled S represents a reliable starting point. During this test, the mobile device stops and restarts the navigation several times.

FIG. 27 illustrates GNSS positions captured by the mobile device moving along the path illustrated in FIG. 26. The GNSS positions are indicated by small circles 272, consecutive parts of which are joined by thin dashed lines 271. Since many locations will be stacked on top of each other, not all over 400 capture locations are shown for clarity, but the general orientation of the capture locations is maintained. As shown in fig. 27, when the mobile device is inside a house, the GNSS position error increases significantly. The out-of-bounds at the end of the lane is true, but the out-of-bounds at the right and bottom of the fence area are false.

FIG. 28 illustrates trusted locations captured by the mobile device moving along the path shown in FIG. 26. Respective trusted locations recorded in synchronism with respective GNSS locations shown in fig. 27 are represented by small blocks 282, successive portions of which are joined by thin dashed lines 281. Since many locations will be stacked upon one another, not all over 400 capture locations are shown for clarity, but the general orientation of the capture locations is maintained. As shown in fig. 28, the path of the trusted location illustrates that the error between it and the path taken by the mobile device is minimal and no false out-of-bounds has occurred.

According to many different embodiments of the present general inventive concept, a mobile device for tracking a moving object to thereby define it within a control area may determine a trusted position and velocity of the moving object that is more reliable than conventionally derived GNSS positions and velocities. The trusted position and velocity are quantities derived from one or more of GNSS position and velocity, motion confirmation from an independent motion detector, and such quantities: may include GNSS signal indicators, GNSS solution indicators, prior trusted location and velocity, and any combination thereof. In a good signal environment, the trusted position and velocity can more closely track the GNSS position and velocity at a verified intermediate velocity. As the GNSS signal environment deteriorates or the GNSS speed decreases, the trusted position and speed track the GNSS position and speed less closely. The trusted speed and position may stop tracking GNSS position and speed completely if the GNSS signal environment or GNSS speed is below a minimum acceptable level. Furthermore, many different embodiments of the present general inventive concept conserve energy by employing a separate motion detector that can indicate when a trusted location and velocity needs to be determined.

The concepts and technologies disclosed herein are not limited to any particular type of moving object and may be applied to many different other applications and objects without departing from the spirit and scope of the present general inventive concept. For example, although a dog collar worn by a dog is discussed herein, the present general inventive concept is not limited to any particular type of animal and may also be used by human or mechanically moving objects.

It is noted that the simplified diagrams and drawings do not show all the different connections and combinations of the different components, however, based on the components shown, the drawings and the description provided herein, a person skilled in the art will understand how to achieve such connections and combinations with sound engineering judgment.

The present general inventive concept can be embodied as computer readable codes on a computer readable medium. The computer readable medium may include a computer readable recording medium and a computer readable transmission medium. The computer-readable recording medium is any data storage device that can store data as a program which can be read by a computer system thereafter. Examples of the computer readable recording medium include read-only memory (ROM), random-access memory (RAM), CD-ROMs, DVDs, magnetic tapes, floppy disks, and optical data storage devices. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. The computer readable transmission medium may transmit carrier waves and signals (e.g., wired or wireless data transmission through the internet). Also, functional programs, codes, and code segments for implementing the present general inventive concept can be easily construed by programmers skilled in the art to which the present general inventive concept pertains.

Many variations, modifications, and additional embodiments are possible, and accordingly, all such variations, modifications, and embodiments are to be regarded as being within the spirit and scope of the general inventive concept. For example, no particular act or element, any particular order of acts, or any particular interrelationship of elements, is required to be implied by the invention or any claim claiming any priority hereto, unless explicitly stated otherwise. Moreover, any act may be repeated, may be implemented by multiple entities, and/or may replicate any element.

While the present general inventive concept has been illustrated by a description of several exemplary embodiments, it is not intended to restrict or in any way limit the scope of the inventive concept to such description and illustrations. Rather, the description, drawings, and claims herein are to be regarded as illustrative in nature and not as restrictive, and further embodiments will be readily apparent to those of ordinary skill in the art upon reading the foregoing description and drawings.

Claims

1. An apparatus for tracking a moving object based on Global Navigation Satellite System (GNSS) data, comprising:

a motion detector that detects motion of a moving object independent of GNSS data;

a trusted position and velocity determination unit receiving the GNSS data and determining a current trusted position and a current trusted velocity of the moving object,

wherein the current trusted location is a sum of a previous trusted location and a product of an attenuated location difference and a location tracking coefficient, the attenuated location difference is a product of a difference between the current GNSS location and the previous trusted location and a location attenuation coefficient, the location attenuation coefficient is a function of a latest GNSS location solution indicator and a GNSS signal indicator and a previous GNSS location solution indicator and a GNSS signal indicator, and the location tracking coefficient is a function of a trusted speed and a motion detected by the motion detector, and

wherein the current trusted speed is a function of a prior trusted speed and an attenuation speed estimate, the attenuation speed estimate being a product of the speed estimate and a speed attenuation coefficient, the speed estimate being a function of the prior speed estimate and a GNSS speed estimate, the speed attenuation coefficient being a function of a latest GNSS speed plan index and a prior GNSS speed plan index, and the speed attenuation coefficient being a function of a GNSS signal index; and

a boundary testing unit which evaluates whether the boundary is out of range according to a current credible position and a current credible speed of the mobile object relative to the predetermined boundary.

2. The apparatus of claim 1, wherein a lower limit of the location decay factor is set by determining whether a prior trusted location and speed resulted in a boundary violation.

3. The apparatus of claim 1, wherein a lower limit of the velocity decay factor is set by determining whether a prior trusted location and velocity resulted in a boundary violation.

4. The apparatus of claim 1, wherein the current trusted speed is also a function of a GNSS solution indicator.

5. The apparatus of claim 1, wherein the current trusted speed is also a function of a previous trusted location and whether speed results in an out-of-range.

6. The apparatus of claim 1, wherein the GNSS solution indicator comprises a horizontal precision factor, an estimated horizontal position error, an estimated velocity error, a horizontal precision factor times an estimated horizontal position error, a horizontal precision factor times an estimated velocity error, or any combination thereof.

7. The apparatus of claim 1, wherein the GNSS signal indicators comprise a quantity representative of an overall observable GNSS signal-to-noise ratio, where observable refers to all GNSS signals used to determine GNSS position and velocity, and/or a quantity representative of an overall qualified GNSS signal-to-noise ratio, where qualified refers to all decodable GNSS signals emitted by satellites above a predetermined altitude threshold.

8. The apparatus of claim 1, wherein the motion detector is a micro-electro-mechanical system (MEMS) device.

9. The apparatus of claim 1, wherein the motion detector is an omni-directional vibration sensor.

10. The apparatus of claim 1, wherein a predetermined location within a control area is used as an initial starting location for the moving object.

11. The apparatus of claim 1, wherein a prior trusted location and velocity is maintained in response to a motion detector not detecting motion of a moving object.

12. The apparatus of claim 1, wherein the GNSS data comprises GNSS PVT (position, velocity, time) signals, pseudorange error data, time assistance data, ephemeris assistance data, or any combination thereof.

13. The apparatus of claim 1, wherein the moving object is a human or an animal.

14. The device of claim 1, wherein the device is attached to or worn by a mobile object.

15. A method of tracking a moving object based on Global Navigation Satellite System (GNSS) data, the method comprising the steps of:

detecting, with a motion detector, motion of a moving object without relying on GNSS data;

receiving GNSS data and determining a current trusted position and a current trusted speed of the moving object,

wherein the current trusted speed is a function of a previous trusted speed and an attenuation speed estimate, the attenuation speed estimate is a product of the speed estimate and a speed attenuation coefficient, the speed estimate is a function of the previous speed estimate and a GNSS speed estimate, the speed attenuation coefficient is a function of a latest GNSS speed scheme index and a previous GNSS speed scheme index, and the speed attenuation coefficient is a function of a GNSS signal index; and

and evaluating whether the boundary is crossed according to the current credible position and the current credible speed of the mobile object relative to the preset boundary.

16. The method of claim 15, wherein the GNSS solution indicator comprises a horizontal precision factor, an estimated horizontal position error, an estimated velocity error, a horizontal precision factor times an estimated horizontal position error, a horizontal precision factor times an estimated velocity error, or any combination thereof.

17. The method of claim 15, wherein the GNSS signal indicators comprise a quantity representative of an overall observable GNSS signal-to-noise ratio, where observable refers to all GNSS signals used to determine GNSS position and velocity, and/or a quantity representative of an overall qualified GNSS signal-to-noise ratio, where qualified refers to all decodable GNSS signals emitted by satellites above a predetermined altitude threshold.

18. The method of claim 15, wherein a predetermined location within a control area is used as an initial starting location for the moving object.

19. The method of claim 15, wherein in response to no motion of a moving object being detected, a prior trusted location and velocity is maintained.

20. The method of claim 15, wherein the GNSS data comprises GNSS PVT (position, velocity, time) signals, pseudorange error data, time assistance data, ephemeris assistance data, or any combination thereof.

21. The method of claim 15, wherein the moving object is a human or an animal.

22. A non-transitory computer-readable storage medium having recorded thereon a program for causing a computer to track a moving object based on Global Navigation Satellite System (GNSS) data to detect a boundary crossing, the method comprising the steps of:

wherein the current trusted location is a sum of a previous trusted location and a product of an attenuated location difference and a location tracking coefficient, the attenuated location difference is a product of a location attenuation coefficient and a difference between the current GNSS location and the previous trusted location, the location attenuation coefficient is a function of a latest GNSS location solution indicator and a GNSS signal indicator and a previous GNSS location solution indicator and a GNSS signal indicator, and the location tracking coefficient is a function of a trusted speed and a motion detected by the motion detector, and