Data transmission in system of monitoring of transport — technology DDF
a Rare example of the patent in Russia can actually work in the field of GPS applications. Technology DDF is an acronym for Dynamic Data Flow. It's patented as an invention in Russia and the United States (patent RF 2010127419, U.S. patent 8,498,774 B2) and is used in the system of monitoring LOCARUS.
With its help reduces GPRS traffic from the monitoring devices, the required volume of memory in the device, time of session, as well as for DDF virtually no restrictions on the number of controlled parameters of a vehicle, mounted equipment and cargo.
The original purpose was, of course, the traffic — when developed the DDF, the data transfer costs were much higher than today. As development progressed in parallel with the development of a new instrument of monitoring, it was decided also to maximize opportunities to connect sensors.
As usual the devices of satellite monitoring? Periodically or on event (within the virtual circle, the passage of a specified distance, change course, not within the geofence, triggering a sensor, the arrival of SMS, etc.) the device forms a so-called "point": a set of data including coordinates, time, sometimes the rate and speed sensors. With the development of the system, with the advent of new devices/firmware versions this package can change the format of, for example, one format is used for transmission of indications of the fuel level sensors, one for the transmission temperature reading from microsphere thermal sensors.
In any case, the data format and the number of sources, rigidly defined during the development phase of the Protocol. To change anything means to condemn all of a group of application developers to suffering, and himself to damnation. If the developer decided that submersible level sensors fuel can be a maximum of two third and fourth sensor integrator supply will not ever be able to. If the developer decided once that the data on the air pressure in the air suspension of the tractor is not needed — then they never will be transferred to the application software. Change the "normal" Protocol — a landmark for the mass manufacturer and painful for the consumer.
In the DDF Protocol is fundamentally refused to record "points" of the track. Question: "how many points is placed in the memory of the device LOCARUS?" has no single answer, all depends on the conditions of operation of the device.
So, data compression. But to compress the data by conventional methods of mathematical compression, is highly undesirable. Because in this case, it will be lost the most important quality of system of monitoring efficiency! Mathematical methods work effectively for a large enough array and we need to pass (sometimes) almost continuously!
Thus, the developers came to the idea of separation of reference and intermediate frames. In the reference frames, the frequency of which is tuned to the task, but is usually 300 seconds are passed the absolute values of all controlled parameters. Coordinates, date / time, heading, number of visible satellites, power supply and standby battery and its sensors. A claim can be indefinitely large number of sensors, limit user can only considerations of bandwidth and data charges. In the intermediate frames is transmitted increment values. The increment of time from the last key frame and increment the testimony of any of the variables.
Since the maximum possible period between the reference frames is limited to force, based on the real velocity of vehicles is possible to limit the dimension record fields for the coordinates. The dimension of the field recording time is also limited, and the dimension fields of a record of other controlled parameters (we call them "logical channels") selected by the user during configuration.
Logical channels are universal, and externally differ solely by the dimensionality. The application program uses a configuration file generated when configuring the device in order to understand what channel comes speed, and in which the fuel level.
That is — we get an extremely flexible system. With the right settings, standing car with the engine switched off transmits only key frames every 5 minutes. Dispatcher loses connection with the car, but have a meager GPRS traffic.
The motion passed keyframes, plus (for vehicle equipped with fuel level sensors and temperature in the refrigerator):
— pressing a panic button or fire alarming sensors instantly
— the coordinates, if you change the rate (typically 3-5 deg.)
— change of fuel level by the consumption of
— temperature changes, if they occurred has exceeded the threshold of sensitivity to changes
In fact, implemented highly specialized data compression algorithm applicable to the particular field of satellite monitoring of land and water transport. In aviation DDF work "as is" will not — at least need to review the range of speeds.
Of course, the implementation of the DDF Protocol decoding on the server side is much more difficult than any other. Hence, the low prevalence of the devices LOCARUS — they are technologically difficult to adapt to third-party software. However, consumers appreciate the flexibility and work quality in weak networks. The quality of this stems from the fact that the terminal requires much less time for data transmission after area of GSM coverage, or when high traffic demands.
Article based on information from habrahabr.ru
With its help reduces GPRS traffic from the monitoring devices, the required volume of memory in the device, time of session, as well as for DDF virtually no restrictions on the number of controlled parameters of a vehicle, mounted equipment and cargo.
The original purpose was, of course, the traffic — when developed the DDF, the data transfer costs were much higher than today. As development progressed in parallel with the development of a new instrument of monitoring, it was decided also to maximize opportunities to connect sensors.
As usual the devices of satellite monitoring? Periodically or on event (within the virtual circle, the passage of a specified distance, change course, not within the geofence, triggering a sensor, the arrival of SMS, etc.) the device forms a so-called "point": a set of data including coordinates, time, sometimes the rate and speed sensors. With the development of the system, with the advent of new devices/firmware versions this package can change the format of, for example, one format is used for transmission of indications of the fuel level sensors, one for the transmission temperature reading from microsphere thermal sensors.
In any case, the data format and the number of sources, rigidly defined during the development phase of the Protocol. To change anything means to condemn all of a group of application developers to suffering, and himself to damnation. If the developer decided that submersible level sensors fuel can be a maximum of two third and fourth sensor integrator supply will not ever be able to. If the developer decided once that the data on the air pressure in the air suspension of the tractor is not needed — then they never will be transferred to the application software. Change the "normal" Protocol — a landmark for the mass manufacturer and painful for the consumer.
In the DDF Protocol is fundamentally refused to record "points" of the track. Question: "how many points is placed in the memory of the device LOCARUS?" has no single answer, all depends on the conditions of operation of the device.
So, data compression. But to compress the data by conventional methods of mathematical compression, is highly undesirable. Because in this case, it will be lost the most important quality of system of monitoring efficiency! Mathematical methods work effectively for a large enough array and we need to pass (sometimes) almost continuously!
Thus, the developers came to the idea of separation of reference and intermediate frames. In the reference frames, the frequency of which is tuned to the task, but is usually 300 seconds are passed the absolute values of all controlled parameters. Coordinates, date / time, heading, number of visible satellites, power supply and standby battery and its sensors. A claim can be indefinitely large number of sensors, limit user can only considerations of bandwidth and data charges. In the intermediate frames is transmitted increment values. The increment of time from the last key frame and increment the testimony of any of the variables.
Since the maximum possible period between the reference frames is limited to force, based on the real velocity of vehicles is possible to limit the dimension record fields for the coordinates. The dimension of the field recording time is also limited, and the dimension fields of a record of other controlled parameters (we call them "logical channels") selected by the user during configuration.
Logical channels are universal, and externally differ solely by the dimensionality. The application program uses a configuration file generated when configuring the device in order to understand what channel comes speed, and in which the fuel level.
That is — we get an extremely flexible system. With the right settings, standing car with the engine switched off transmits only key frames every 5 minutes. Dispatcher loses connection with the car, but have a meager GPRS traffic.
The motion passed keyframes, plus (for vehicle equipped with fuel level sensors and temperature in the refrigerator):
— pressing a panic button or fire alarming sensors instantly
— the coordinates, if you change the rate (typically 3-5 deg.)
— change of fuel level by the consumption of
— temperature changes, if they occurred has exceeded the threshold of sensitivity to changes
In fact, implemented highly specialized data compression algorithm applicable to the particular field of satellite monitoring of land and water transport. In aviation DDF work "as is" will not — at least need to review the range of speeds.
Of course, the implementation of the DDF Protocol decoding on the server side is much more difficult than any other. Hence, the low prevalence of the devices LOCARUS — they are technologically difficult to adapt to third-party software. However, consumers appreciate the flexibility and work quality in weak networks. The quality of this stems from the fact that the terminal requires much less time for data transmission after area of GSM coverage, or when high traffic demands.
Комментарии
Отправить комментарий