EP3490172A1

EP3490172A1 - Position-based transmitter selection

Info

Publication number: EP3490172A1
Application number: EP17203323.5A
Authority: EP
Inventors: Philipp Schmauderer; Raphael GRAEFF; Christoph Benz; Thorsten Mayer
Original assignee: Harman Becker Automotive Systems GmbH
Current assignee: Harman Becker Automotive Systems GmbH
Priority date: 2017-11-23
Filing date: 2017-11-23
Publication date: 2019-05-29

Abstract

A system and method are configured to provide a plurality of stored transmitter records, each transmitter record comprising a position data set representing the position of this transmitter, and a horizon data set corresponding with this transmitter, the horizon data set representing the lengths of lines of sight at various angles around the position of this transmitter. The system and method are further configured to receive a position data set representing a position of interest and retrieve, from the memory, selected transmitter records from the plurality of transmitter records associated with positions of transmitters within a predetermined distance from the position of interest, and to compile a list including at least one position data set of at least one transmitter that is in a line of sight with the position of interest.

Description

BACKGROUND

1. Technical Field

The disclosure relates to a system and method (generally referred to as a "system") for position-based transmitter selection.

2. Related Art

Radio receivers may include a single tuner or a multiplicity of tuners and may allow to automatically seek an alternative frequency on which a currently received radio program is also broadcasted and to tune to this alternative frequency when the reception quality on the currently tuned-in frequency falls below a certain limit. For example, when a listener travels over a long distance that exceeds the transmission range of an individual radio transmitter broadcasting a particular radio program on a particular frequency, these radio receivers automatically switch to an alternative frequency on which another transmitter broadcasts the same program and provides, at the current position of the receiver, a better reception quality than the transmitter of the currently tuned-in frequency so that the listener is able to continue listening to the particular radio program without having to manually seek an alternative frequency.
However, receivers with a single tuner do not provide an uninterrupted listening experience since the process of seeking an alternative frequency of the same program can take considerable time, within which the receiver repeatedly tunes to other frequencies and explores whether the reception quality there is better than on the currently tuned-in frequency. Such interruptions, particularly when occurring during transmissions of important program contents, such as warnings etc., are extremely annoying for the listener even if the interruptions only last a few seconds. Receivers with two or more tuners do not exhibit such interruptions but are complex and, thus, costly since at least one additional tuner and an enhanced control structure are required. Therefore, there is a need for an improved technique for automatically determining alternative frequencies on which a particular program is available at a particular position.

SUMMARY

An example system includes a primary memory which stores a plurality of transmitter records, each transmitter record comprising a position data set representing the position of this transmitter, and a horizon data set corresponding with this transmitter, the horizon data set representing the lengths of lines of sight at various angles around the position of this transmitter. The system further comprises a controller configured to receive a position data set representing a position of interest and to retrieve, from the memory, selected transmitter records from the plurality of transmitter records associated with positions of transmitters within a predetermined distance from the position of interest, the controller being further configured to compile a list that includes no or at least one position data set of at least one transmitter that is in a line of sight with the position of interest.
An example method includes providing a plurality of stored transmitter records, each transmitter record comprising a position data set representing the position of this transmitter, and a horizon data set corresponding with this transmitter, the horizon data set representing the lengths of lines of sight at various angles around the position of this transmitter. The method further includes receiving a position data set representing a position of interest and retrieve, from the memory, selecting transmitter records from the plurality of transmitter records associated with positions of transmitters within a predetermined distance from the position of interest, and compiling a list that includes no or at least one position data set of at least one transmitter that is in a line of sight with the position of interest.
Other systems, methods, features and advantages will be, or will become, apparent to one with skill in the art upon examination of the following detailed description and appended figures. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the following claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The system may be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views.

Figure 1 is a schematic diagram illustrating an exemplary topographic map in which the positions of a vehicle and three transmitters are identified.
Figure 2 is a cross-sectional view illustrating the situation outlined by the topographic map shown in Figure 1.
Figure 3 is a schematic diagram illustrating a horizon curve for a particular transmitter which reflects the length of the line of sight from the transmitter's perspective in every direction around the transmitter.
Figure 4 is a schematic diagram illustrating an exemplary system for position based transmitter selection.
Figure 5 is a flow chart of a method for position-based transmitter selection.
Figure 6 is a schematic diagram illustrating an exemplary transmitter record.
Figure 7 is a schematic diagram illustrating an exemplary list of position data sets of transmitters that are in a line of sight with a position of interest.

DETAILED DESCRIPTION

Figure 1 illustrates an exemplary topographic map in which the geo positions of a vehicle 100 carrying a radio receiver system (not shown in Figure 1) and three transmitters 101, 102 and 103 are identified. In modern mapping, a topographic map is a type of map that includes a quantitative representation of relief, usually using contour lines such as contour lines 104 in Figure 1, but may also use a variety of alternative schemes. A contour line is a line connecting places of equal elevation. The topographic map may show both natural and man-made features. The geo positions marked in a topographic map, i.e., their coordinates are three-dimensional and so are the geo positions of the vehicle 100 and the three transmitters 101, 102 and 103 shown in Figure 1. This means that the three-dimensional coordinates of a particular geo position not only include a latitude and a longitude of a particular geo position as with two-dimensional coordinates but also an altitude, also referred to as elevation such as the elevation above sea level. Elevation is considered herein as the difference between the ground level and the sea level to which, e.g., a height (above ground level) of a broadcasting tower carrying the transmitter, the receiver and/or an antenna thereof may be added, referred to herein as height of the transmitter or receiver above ground. In the following, geo position is simply referred to as "position" and can be two-dimensional or three-dimensional, as the case may be.
Figure 2 is a cross-sectional view of the situation outlined by the topographic map shown in Figure 1 and illustrates the importance of the elevation coordinates (and additionally the height) of the transmitter position, the receiver position and the landscape relief there-between for assessing the transmission quality between transmitter and receiver. If sufficient broadcast power is assumed, as well as a negligible transmitter height and a flat surface (e.g., on sea level) between transmitter and receiver, there will be, due to earth's curvature 200, a maximum transmission distance between transmitter and receiver within which a direct signal transmission from the transmitter to the receiver is possible. This maximum transmission distance can be seen as a length of a line of sight, i.e., the length of an uninterrupted line between transmitter and receiver (e.g., lines 201, 202, 203 between the vehicle 100 and the transmitters 101, 102, 103). However, the length of the line of sight may be extended when at least one of the elevation at the transmitter's position, the elevation at the receiver's position, the height of the transmitter above ground level, and the height of the receiver above ground level are increased. Furthermore, the relief of the landscape between transmitter and receiver may interrupt the line between transmitter and receiver, and thus reduce the length of the line of sight from a receiver's perspective or a transmitter's perspective. In the above considerations, only a primary transmission path between transmitter and receiver is considered, thereby neglecting any secondary paths, e.g., due to reflections.
As shown in Figure 2, the line 201 between the vehicle 100 carrying the receiver and the transmitter 101 which is disposed on top of a broadcasting tower 203 on a hill 204 is interrupted by an elevation such as a hill 205 which shadows the vehicle 100. In contrast, the line 202 between vehicle 100 and transmitter 102, which is disposed even more distant from the vehicle 100 than transmitter 101 and which is disposed on top of a broadcasting tower 206 on a hill 207 (provided transmitter 102 has sufficient broadcast power), is neither interrupted by the earth's curvature 200 nor by any landscape relief. A similar scenario applies to line 203 between vehicle 100 and transmitter 103 which is disposed closer to the vehicle 100 than transmitter 101 and which is disposed on top of a broadcasting tower 208 on a hill 209. In the above examples, along lines 202 and 203 the lines of sight from the vehicle's perspective extend to transmitters 102 and 103 (and vice versa). However, regarding line 101 between vehicle 100 and transmitter 101 the line of sight both from the vehicle's perspective and the transmitter's perspective ends at the hill 205.
Referring to Figure 3, based on the considerations presented above, a two-dimensional transmission range profile for any transmitter 301 may be deduced from the three-dimensional position (including elevation) of the transmitter 301, from all possible three-dimensional positions (including elevations) of a receiver (not shown) within a maximum transmission distance 302, from the three-dimensional relief of the surrounding landscape (including elevations) and, as the case may be, from the height of the transmitter 301. The transmission range profile may be depicted as a two-dimensional horizon (curve) 303 which reflects the length of the line of sight from the transmitter's perspective in every (two-dimensional) direction around the transmitter 301. The horizons for a multiplicity of transmitters may be stored in database together with other transmitter related data. The horizon may be stored as a set of data that include the lengths of the line of sight (distance between transmitter and horizon) at certain angles around the transmitter, e.g., in 1 degree steps. The horizon may be determined from topographic maps such as the one shown in Figure 1 or by way of shuttle radar topography mission (SRTM) data, which are three-dimensional data. The database may further store the longitude and latitude data (geo position) of the respective transmitter, and, optionally, transmission frequencies of the respective transmitter and program identifiers related to the frequencies, the height of a broadcasting tower carrying the transmitter, the broadcast power of the transmitter, and/or alternative frequency handling data.
Referring to Figure 4, an exemplary system 400 may control a radio receiver 401 operatively connected between an antenna 402 and a loudspeaker 403 (and/or a video screen) and may include various components. For example, the system 400 may include a positioning device 404, a controller 405, and a database 406. These components may be grouped together in any suitable manner to provide the desired function. For example, at least one of controller 405 and database 406 may be included in the radio receiver 401 whereas the positioning device 404 may be embodied as a separate device. In other examples, the components may be combined or grouped together such that they are integrated or distributed across different pieces of equipment. Accordingly, in other examples, several components may be combined into a single component or individual components may be broken down into several components. In other examples, the functionality of the components may be isolated or overlap with other components. Each of the components may be implemented in hardware, software, firmware, or combinations thereof.
In certain examples, the positioning device 404, which is used to detect the current (two-dimensional) position of the vehicle carrying the receiver, may include, for example, a global positioning system (GPS) receiver. The database 406 may be recorded in a local storage device such as a non-volatile memory or a hard drive disposed in the vehicle, or in a remote storage device such as a cloud or server system to which the system 400 may be (wirelessly) connected. The controller may be or include a processor such as microprocessor, signal processor or microcontroller that executes instructions received from an adequate software and/or firmware to achieve the desired function or method.
A flow chart of an exemplary method performed by the controller 405 in connection with positioning device 404 and database 406 is described below in connection with Figure 5. The controller 405 may receive the current position information, i.e., receiver position coordinates, from the positioning device 404 (procedure 501) and identify transmitters within a certain distance from the vehicle (procedure 502) based on transmitter data records retrieved from the database 406 (procedure 503). The records include transmitter positions and horizon coordinates for the identified transmitters. From the vehicle position (longitude, latitude) and the transmitter positions (longitude, latitude) the angles of the transmitters relative to the vehicle (procedure 504) and the (shortest) distances between the vehicle and the transmitters (procedure 505) are determined, e.g., by way of the Law of Cosines. From the determined angles and distances, the distances at the corresponding angles for the identified transmitters are determined (procedure 506), e.g., by way of the Law of Cosines. Then, each distance at the corresponding angle is compared to the horizon at this particular angle for a particular transmitter as recorded in the database 406 (procedure 507) to evaluate whether the distance at this particular angle is within the horizon of the particular transmitter (procedure 508) or not (procedure 509). All identified transmitters for which the position of the vehicle falls within the respective horizon are output to the receiver 401 as a list of receivable transmitters (procedure 510). After a certain change in time or in the vehicle's position, e.g., after travelling for a certain time or distance, the method may be restarted to evaluate the receivable transmitters in the current position (procedure 511). The output list may include further data retrieved from the database 406 such as transmitter identification, program identification, alternative frequency handling information etc. Further, in the examples presented above it is assumed that the broadcast power of the transmitters is sufficient within the maximum transmission distance and, thus, within the horizon. Should the broadcast power not meet the above requirement, this can be included in the horizon data.
The receiver 401 can, by way of the list received from the controller 405, determine at any time what alternative transmitter is available for broadcasting the same program as the one currently tuned in, just like in a two-tuner system but actually without a second tuner. Furthermore, the system described herein is able to provide, in contrast to any one-tuner or two-tuner system, a list of receivable transmitters also for positions the vehicle may reach in the future, e.g., for a position which is a certain distance ahead of the vehicle and which the vehicle will reach on its route only in a certain time. This allows changing the transmitter in good time before quality issues with the currently tuned in transmitter arise. The selection of an alternative transmitter may be performed based on transmitter identification data and program identification data such as program identification (PI) data in analog radio systems with RDS, ident data (ID) in digital radio systems or "handover" data in digital television receivers.
As described above in connection with Figure 5, the list of receivable transmitters may be furnished during operation of the vehicle/receiver dependent on the current or future position of the vehicle/receiver. Alternatively, a list of the receivable transmitters may be furnished initially, i.e., before installation of the system or during activation of the vehicle/receiver, for a multiplicity of squares with a certain length, into which an underlying map is divided. For each square a corresponding list of receivable transmitters is recorded in the database or any other storage. The square may be identified by the two-dimensional coordinates (longitude, latitude) of the center of the square. When the vehicle/receiver enters a particular square, which can be determined by way of, e.g., GPS data, the corresponding list for this square is retrieved from the database and provided to the receiver. Thus, the method described above in connection with Figure 5 would be performed for each square and the resulting lists would be stored in the existing database or another database or in any other storage device. In this case the controller 405 may receive the current position information, i.e., receiver position coordinates, from a position generator device instead of a GPS device 404 in procedure 501 so that respective positions at given times are generated and input into the controller 405. The resulting lists may be stored in a secondary storage where they can be selected by a positioning device similar to positioning device 404. For example, the database 406 shown in Figure 4 may be used either as primary database or secondary database.
Referring to Figure 6, an exemplary database 601 stored in storage may include a plurality of transmitter records such as an exemplary transmitter record 602. The transmitter record 602 includes an identification data set 603 identifying the corresponding transmitter, a position data set 604 representing the position (latitude, longitude) of this transmitter, a horizon data set identifying for a plurality of angles 606 the corresponding lengths 607 of the respective line of sight, a program identification data set 608 identifying one or more programs broadcasted by the corresponding transmitter, and a frequency identification data set 609 identifying the respective frequencies on which the programs are broadcasted.
Figure 7 depicts an exemplary list 701 of receivable transmitters and the programs broadcasted by these transmitters. The list 701 includes a plurality of columns, of which a column 702 identifies the transmitters that are receivable at a position of interest, another column 703 identifies the programs broadcasted by these transmitters and still another column 704 identifies the frequencies at which the particular programs identified in column 703 are broadcasted. As can be seen, some of the programs (see, e.g., SWR1, B3, HR2) are broadcasted by separate transmitters (see, e.g., Sender Aalberg, Sender Dold) on separate frequencies so that the receiver can optionally switch between these frequencies in order to maintain an undisturbed listening experience for a listener. The list may include further data (not shown) if desired or required.
With the herein described systems and methods, the performance of single tuner receivers can be improved in that the mute times can be significantly reduced (even down to zero) since no frequency scans for furnishing a list of receivable transmitters need be performed. Further, the systems and methods described herein allow finding alternative frequencies more reliably and more successfully than with conventional systems and methods since no minimum transmitting quality for alternative frequencies is required. In multi-tuner receivers, the work load of one or more back ground tuners can be reduced so that these resources become available for other duties such as data messaging.
The description of embodiments has been presented for purposes of illustration and description. Suitable modifications and variations to the embodiments may be performed in light of the above description or may be acquired from practicing the methods. For example, unless otherwise noted, one or more of the described methods may be performed by a suitable device and/or combination of devices. The described methods and associated actions may also be performed in various orders in addition to the order described in this application, in parallel, and/or simultaneously. The described systems are exemplary in nature, and may include additional elements and/or omit elements.
As used in this application, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural of said elements or steps, unless such exclusion is stated. Furthermore, references to "one embodiment" or "one example" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. The terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements or a particular positional order on their objects.
While various embodiments of the invention have been described, it will be apparent to those of ordinary skilled in the art that many more embodiments and implementations are possible within the scope of the invention. In particular, the skilled person will recognize the interchangeability of various features from different embodiments. Although these techniques and systems have been disclosed in the context of certain embodiments and examples, it will be understood that these techniques and systems may be extended beyond the specifically disclosed embodiments to other embodiments and/or uses and obvious modifications thereof.

Claims

A system comprising:
a primary memory storing a plurality of transmitter records, each transmitter record comprising a position data set representing the position of this transmitter, and a horizon data set corresponding with this transmitter, the horizon data set representing the lengths of lines of sight at various angles around the position of this transmitter; and

a controller configured to receive a position data set representing a position of interest and to retrieve, from the memory, selected transmitter records from the plurality of transmitter records associated with positions of transmitters within a predetermined distance from the position of interest, the controller further being configured to compile a list that includes no or at least one position data set of at least one transmitter that is in a line of sight with the position of interest.
The system of claim 1, further comprising a positioning unit configured to determine a current position of a vehicle and to provide a position data set representing the current position of the vehicle to the controller, the current position of the vehicle being the position of interest.
The system of claim 1, further comprising:
a position generator configured to provide a series of data sets representing a plurality of different positions of interest to the controller; and

a secondary memory configured to store lists of transmitters that are in a line of sight with the positions of interest for the series of data sets representing different positions of interest.
The system of claim 3, further comprising a positioning unit operatively coupled with the secondary memory and configured to determine a current position of a vehicle and to provide an address representing the current position of the vehicle to the secondary memory, the address identifying a corresponding list of no or at least one transmitter that is in a line of sight with the current position of the vehicle.
The system of any of claims 1 to 4, wherein each transmitter record further comprises at least one of: an identification data set identifying the corresponding transmitter, a program identification data set identifying one or more programs broadcasted by the corresponding transmitter, and a frequency identification data set identifying one or frequencies on which the one or more programs are broadcasted by the corresponding transmitter.
The system of any of claims 1 to 5, wherein, in order to generate the list including no or at least one position data set of at least one transmitter that is in a line of sight with the position of interest, the controller is further configured to:
determine the angle between the at least one transmitter and the vehicle;

determine the distance between the at least one transmitter and the vehicle;

compare the determined distance between the at least one transmitter and the vehicle to the length of the line of sight at the determined angle between the at least one transmitter and the vehicle; and

add the at least one transmitter to the list if the determined distance between the at least one transmitter and the vehicle is less than the length of the line of sight at the determined angle between the at least one transmitter and the vehicle.
The system of any of claims 1 to 6, wherein:
each transmitter record further comprises a power data set representing the transmitting power of the corresponding transmitter; and

the controller is configured to apply a reducing factor to the lengths of lines of sight at various angles around the position of this transmitter dependent on the power data set.
A method comprising:
providing a plurality of stored transmitter records, each transmitter record comprising a position data set representing the position of this transmitter, and a horizon data set corresponding with this transmitter, the horizon data set representing the lengths of lines of sight at various angles around the position of this transmitter;

receiving a position data set representing a position of interest and retrieving, from the memory, selected transmitter records from the plurality of transmitter records associated with positions of transmitters within a predetermined distance from the position of interest; and

compiling a list including no or at least one position data set of at least one transmitter that is in a line of sight with the position of interest.
The method of claim 8, further comprising determining a current position of a vehicle and providing a position data set representing the current position of the vehicle to the controller, the current position of the vehicle being the position of interest.
The method of claim 8, further comprising:
providing a series of data sets representing a plurality of different positions of interest to the controller; and

storing lists of transmitters that are in a line of sight with the positions of interest for the series of data sets representing different positions of interest.
The method of claim 10, further comprising determining a current position of a vehicle and identifying a corresponding list of no or at least one transmitter that is in a line of sight with current position of the vehicle.
The method of any of claims 8 to 11, wherein each transmitter record further comprises at least one of: an identification data set identifying the corresponding transmitter, a program identification data set identifying one or more programs broadcasted by the corresponding transmitter, and a frequency identification data set identifying one or frequencies on which the one or more programs are broadcasted by the corresponding transmitter.
The method of any of claims 8 to 12, wherein, in order to generate the list including no or at least one position data set of at least one transmitter that is in a line of sight with the position of interest, the method further comprises:
determining the angle between the at least one transmitter and the vehicle;

determining the distance between the at least one transmitter and the vehicle;

comparing the determined distance between the at least one transmitter and the vehicle to the length of the line of sight for the determined angle between the at least one transmitter and the vehicle; and

adding the at least one transmitter to the list if the determined distance between the at least one transmitter and the vehicle is less than the length of the line of sight for the determined angle between the at least one transmitter and the vehicle.
The method of any of claims 8 to 13, wherein:
each transmitter record further comprises a power data set representing the transmitting power of the corresponding transmitter; and

the method further comprises applying a reducing factor to the lengths of lines of sight at various angles around the position of this transmitter dependent on the power data set.
A computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the method of any of claims 8 to 14.