Existing methods for meteorological sensing rely on weather balloons, which collect data infrequently and are sparsely deployed. Other methods for meteorological sensing rely on specially equipped aircraft. Further methods include ground based radar stations.
The atmosphere is sparsely sampled both spatially and temporally using existing techniques, such as by weather balloons and by specialty equipped aircraft. Numerical/gridded weather forecast models need an estimate of the atmospheric conditions, such as temperature, humidity, and wind from the surface to high altitudes to run models and make a reasonable weather forecast. Weather radar, for example, cannot offer any of these data when there is no precipitation in the atmosphere to reflect a radar signal. Weather radar does not measure or sample in situ but rather measures reflections in the atmosphere (e.g., from precipitation or other reflective particles) and weather estimates can be calculated from this data. Currently weather balloons sample in situ, but these are typically done only twice a day and in extremely limited locations. Therefore, the vast majority of the atmospheric volume lacks in situ sampling of conditions.
Embodiments of the present disclosure solves the problem of sparse in situ sampling by determining atmospheric conditions (e.g., wind and temperature) from aircraft data using standalone, (e.g., portable) functionality that is not constrained by current secondary surveillance radar (SSR) systems. Embodiments can make wind and temperature estimates using data obtained from commercial, executive, and private aircraft across all altitudes and large regions to help initialize forecast models, among other uses.
The atmospheric conditions determined by embodiments of the present disclosure can improve weather forecasts and provide important data to air traffic control and military decision makers.
In an embodiment, a computer-implemented method and corresponding system for remotely observing an atmospheric condition, include, in response to receiving, at a plurality of fixed antennas, an indication of existence of an airborne aircraft, automatically selecting an antenna from the plurality of fixed antennas based on a location and an orientation of each antenna of the plurality of fixed antennas. The method further includes using the selected antenna, sending to the aircraft a request for data. The method further includes receiving data, at the selected antenna, from the aircraft in response to the request, the data gathered by sensors of the aircraft. The method further includes automatically determining the atmospheric condition based on the data received from the aircraft.
In an embodiment, the atmospheric condition is at least one of wind speed, wind direction, turbulence, and temperature.
In an embodiment, the data received from the aircraft includes at least one of: magnetic orientation of the aircraft, true air speed of the aircraft, ground speed of the aircraft, vertical speed of the aircraft, location of the aircraft, Mach of the aircraft, and track of the aircraft. In another embodiment, the data received from the aircraft can include at least two of: magnetic orientation of the aircraft, true air speed of the aircraft, ground speed of the aircraft, vertical speed of the aircraft, location of the aircraft, Mach of the aircraft, and track of the aircraft.
In an embodiment, the method includes, at each fixed antenna, receiving a plurality of messages from one or more aircrafts, wherein the received messages include aircraft location information. The method further includes determining an intensity of each of the plurality of received messages at each of the fixed antennas. The method further includes determining the orientation of each of the fixed antennas based on the location information, a location of the fixed antennas, and the determined intensity of each message of the plurality of received messages at each of the fixed antennas.
In an embodiment, a method includes receiving from a sensor the indication of existence of the aircraft.
In an embodiment, method further includes associating the atmospheric condition with a location of the aircraft with the indication of existence. In a further embodiment, associating the atmospheric condition with the location further includes associating a plurality of atmospheric conditions with respective locations, and the method further includes storing each of the plurality of atmospheric conditions and respective locations in a database.
In an embodiment, selecting the antenna further includes determining an antenna pointing at the aircraft based on a location of the aircraft, an orientation of the plurality of fixed antenna, and a location of the plurality of fixed antenna.
Another embodiment is directed to a system for remotely observing an atmospheric condition that includes a processor and a memory with computer code instructions stored thereon. In such an embodiment, the processor and the memory, with the computer code instructions, are configured to cause the system to implement any embodiments described herein.
Yet another embodiment is directed to a computer program product for remotely observing an atmospheric condition. The computer program product comprises a computer-readable medium with computer code instructions stored thereon where, the computer code instructions, when executed by a processor, cause an apparatus associated with the processor to perform any embodiments described herein.
Another embodiment is directed to a method for determining orientation of an antenna in a plurality of fixed antennas in an environment. Such an embodiment includes initializing a location of the plurality of fixed antennas in the environment. At each antenna of a plurality of fixed antennas deployed in an environment, the method receives a plurality of messages at least one message from one or more aircraft in response to one or more requests for data, the messages indicating location information for the one or more aircrafts Then, the method determining an intensity of each of the plurality of received messages at each of the fixed antennas. Then the method determining an orientation of each of the fixed antennas relative to the environment based on the location information for the one or more aircraft, the location of the plurality of fixed antennas, and the determined intensity of each message of the plurality of received messages at each of the fixed antennas.
The foregoing will be apparent from the following more particular description of example embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments.
A description of example embodiments follows.
In an embodiment, the present disclosure employs data from aircrafts to determine atmospheric conditions. One such embodiment leverages the inherent capabilities of Mode Selective (Mode S) and Mode Selective Enhanced Surveillance (Mode S EHS) transponders installed on aircraft. Mode S EHS transponders, however, are better suited to this role as they automatically populate data registers of interest relative to weather estimation, where Mode S transponders may populate those registers. Mode S and Mode S EHS systems by design automatically broadcast a response message to an interrogation from an external system. This information in the response can include a call sign or tail number of the aircraft, current altitude and the contents of data registers of interest. From the response, distance from the external system can be calculated using the time of flight of the message. The azimuth of the aircraft is not in this message, but can be calculated in certain circumstances. The system then requests information from the aircraft, and that information can be used to calculate wind and temperature at the aircraft's location. A minority of aircraft store wind and temperature in a register and the system can ask for that directly.
In an embodiment, the method listens (e.g., on 1090 MHz) for squitter messages repeatedly transmitted at about one per second by both Mode S transponder types. A person having ordinary skill in the art can recognize that squitter messages in Mode S systems describe unsolicited downlink transmissions from the aircraft. Such an embodiment maintains a record of recent Mode S addresses received. If the address is not in the current record, the embodiment sends an uplinked formatted message (e.g., UF4 or UF5) on an omni or directional antenna on 1030 MHz to interrogate the transponder's register 0x17 for that system's (the system sending the squitter messages) capabilities.
Mode S messages can interrogate the transponder for information in specific registers, including a list of serviced registers. According to an embodiment, if the interrogated transponder indicates that it populates the data registers of interest, then the aircraft is intelligently interrogated based on the current system needs (e.g., the data needed to determine atmospheric conditions). If a transponder is capable of populating the data associated with registers of interest (registers storing data that can be used to determine atmospheric conditions, including registers 0x50 and 0x60) then a listener system obtains the register data and a processing system can then determine atmospheric conditions (e.g., wind and the ambient air temperature).
In an embodiment, wind is estimated as a function of reported ground speed, true airspeed, true heading, and track angle where true heading is typically estimated as a function of reported magnetic heading, the aircrafts current position, and time. A person having ordinary skill in the art can calculate the wind speed using wind triangle calculations that are known in the art. Further, according to an embodiment, temperature is determined as a function of reported Mach and true airspeed. The temperature can be determined according to the following relationships:
M=v
TAS
/a,
where M is Mach, VTAS is true airspeed, and a is the speed of sound,
a=V
TAS
/M,
a=√{square root over (γ*R*T)},
Where γ is an adiabatic constant known to a person having ordinary skill in the art and R is a gas constant known to a person having ordinary skill in the art
According to yet another embodiment, if, in addition, register 0x53 is also available, then both the temperature and wind can be estimated with much finer resolution. These and the contents of other data registers may be used to estimate other weather conditions such as turbulence.
A unique element of an embodiment is that the interrogations are conducted from a standalone, non-rotating antenna. Herein, the terms non-rotating and fixed may be used interchangeably. Further, it is noted that in embodiments, while the term fixed may be used, fixed indicates that the antenna is not rotating, however the antenna may be on or coupled to a moving object such as a car or aircraft. In other words, the term fixed used herein is defined as fixed rotationally, or stationary rotationally relative to the object to which they are attached, whether the object is moving or stationary. In embodiments, a fixed antenna can be an omni directional antenna. In other embodiments, a fixed antenna can be a directional antenna. In further embodiments, a fixed antenna can be a plurality of directional antennas. In an even further embodiment, the fixed antenna can be one or more directional antennas used in conjunction with an omnidirectional antenna.
In current systems, Mode S and Mode S EHS transponders are interrogated by a rotating antenna having a radar fence. Rotating antenna have the advantage of being able to focus on a specific direction, and can therefore transmit all of its energy in that same direction. This can result in increased range and reduce interference that may result in interrogations broadcast in multiple directions simultaneously. However, such rotating antenna also bring drawbacks. For example, messages in general can only be successfully sent and received while the rotating antenna is facing the target. Therefore, a rotating antenna can therefore only communicate with a particular aircraft during the time it is facing that aircraft.
In an embodiment, a rotationally fixed antenna solves the above problems by sending and receiving messages in all directions simultaneously, whether it is from an array of directional antennas or an omnidirectional antenna. This allows for more frequent sampling of data from aircraft to give a more robust atmospheric information set. In one embodiment, multiple directional antennas are employed with an omni directional antenna, where the omni directional antenna can send and receive messages from nearby aircraft (e.g., within 5-10 miles) and the directional antennas reach aircraft that are further away. In other embodiments, a phased array antenna can be used.
For example, a system embodiment can be deployed on a moving aircraft, manned or unmanned, e.g., UAV/drone, but the system simply does not rotate. In such an embodiment, the present method and system can be used to interrogate other aircraft, such as an aircraft in front of the aircraft including the transponders described above (e.g., transponders of a Mode S system). In an embodiment, the system can be used during flight to modify operation of the aircraft. For example, prior to or during descent, an aircraft utilizing the system can interrogate other aircrafts to determine atmospheric conditions and implement a more optimal descent using the determined estimate of atmospheric conditions (e.g., winds). Such functionality is operationally useful in terms of both adhering to any timing/schedule constraints and in fuel savings. Further, embodiments may utilize the same frequencies for communications as Traffic Alert and Collision Avoidance Systems (TCAS), but request different data as described herein.
In an embodiment, the present disclosure enables an aircraft/transponder to be interrogated from locations and at update rates tailored to the needs of the end user without modifications to existing legacy infrastructure, such as the SSR network. For example, a proposed system embodiment can interrogate aircraft in a dedicated region and at rates on the order of 1 Hz. In comparison, interrogations of aircraft transponders that use rotating airport SSRs or long-range SSRs are limited to about 0.2 Hz and 0.08 Hz respectively.
Another standard way to obtain observations of atmospheric conditions is from commercial aircraft that participate in the Meteorological Data Collection and Reporting System (MDCRS). However, only about 20% of commercial aircraft participate, typically with coarse 1-7 minute sampling periods, and latent reporting (17 minutes delay on average). In contrast, embodiments of the present disclosure can report meaningful estimates of conditions at often as every 1.3 seconds for each aircraft and in near real-time. The present disclosure can update every 1.3 seconds due to the rate of update of data on the registers of interest on the aircraft, however, if an aircraft were to update the registers faster, the condition estimates could be updated faster than ever 1.3 seconds.
Experimental data demonstrating the interrogation techniques of embodiments, and wind and temperature estimates determined as described herein, have been obtained in operational demonstrations using a modified SSR.
While altitude can be reported and range to the reporting transponder/aircraft can be estimated by an embodiment, employing more precise position (e.g., latitude and longitude) estimates can add value to the data estimate. In such an embodiment, the associated positions (e.g., latitude and longitude) can be supplied by primary or secondary surveillance radars, Automatic Dependent Surveillance-Broadcast (ADS-B), or by using a plurality of interrogation systems which are connected in such a fashion that they are communicating with each other, permitting position estimation via multilateration. A person having ordinary skill in the art can recognize that multilateration is a method of determining position of an object based on times of arrival of propagating waves having a known speed.
Embodiments can employ multiple quality control and validation techniques to improve the determined atmospheric conditions and positional estimates that are utilized. For example, embodiments can perform validation for reasonable values of reported data, identify “stuck” reported values, and compensate or invalidate data as a function of reported speed. Further, embodiments can be employed by entities, e.g., the Air Force, NOAA/NWS, FAA, and air carriers, amongst other examples, to determine flight conditions and to modify aircraft operations, such as flight paths.
An example embodiment is directed to a computer-implemented method for remotely observing an atmospheric condition. Such a method, in response to receiving an indication of existence of an airborne aircraft, automatically selects an antenna from a plurality of fixed antennas based on a location and an orientation of each antenna of the plurality of fixed antennas. The method continues by using the selected antenna to send a request for data to the aircraft. In turn, data is received from the aircraft in response to the request and the data received from the aircraft is automatically processed in a manner determining an atmospheric condition. In an embodiment, the data received from the aircraft is processed in known ways to determine the atmospheric condition.
In embodiments, the atmospheric condition is at least one of: wind speed, wind direction, turbulence, and temperature. Further, according to an embodiment, the data received from the aircraft includes at least one of: magnetic orientation of the aircraft, true air speed of the aircraft, ground speed of the aircraft, vertical speed of the aircraft, location of the aircraft, Mach of the aircraft, and track of the aircraft. In an example embodiment, magnetic orientation of the aircraft, true air speed of the aircraft, track of the aircraft, and ground speed of the aircraft are processed to determine wind atmospheric conditions. Further, according to an embodiment, the data received from the aircraft includes at least two of: magnetic orientation of the aircraft, true air speed of the aircraft, ground speed of the aircraft, vertical speed of the aircraft, location of the aircraft, Mach of the aircraft, and track of the aircraft. In an example embodiment, magnetic orientation of the aircraft, true air speed of the aircraft, track of the aircraft, and ground speed of the aircraft are processed to determine wind atmospheric conditions.
In embodiments, the location of the aircraft at the time the requested data is received can also be used in determining wind atmospheric conditions. An estimate of the data source's location (e.g., the aircraft) is employed to change the magnetic orientation to a true orientation (e.g., the orientation relative to truth north as opposed to magnetic north) to make the estimate of the wind. That location estimate can be precise, such as using the location published by the aircraft itself (ADS-B messages) or imprecise, such as using the general location of the receiving antenna (which is typically known) to make the estimate. The more precise the estimate of the location of the subject of interest, the more accurate the wind estimate. Further, another embodiment utilizes vertical speed of the aircraft to improve the determined wind atmospheric condition. In another embodiment, true air speed of the aircraft and Mach of the aircraft are processed to determine temperature.
Yet another embodiment includes receiving from a sensor the indication of existence of the aircraft.
Another embodiment determines the orientation of each antenna of the plurality of fixed antennas. Such functionality can be employed when the orientation of the antennas is not known. In such an embodiment, at each fixed antenna, a plurality of messages from one or more aircrafts are received, wherein the received messages include aircraft location information. The plurality of messages may be any messages sent from an aircraft. Further, it is noted that in an alternative embodiment, the plurality of received messages do not include aircraft location information and the aircraft location information is determined in another way. To continue, intensity of each of the plurality of received messages at each of the fixed antennas is determined. According to an embodiment, “intensity” is magnitude of the received signal as measured at the receiving antenna. In turn, the orientation of each of the fixed antennas is determined based on the location information and the determined intensity of each message of the plurality of received messages at each of the fixed antennas.
Another embodiment is directed to a method for determining orientation of an antenna in a plurality of fixed antennas in an environment. Such an embodiment includes deploying a plurality of fixed antennas in an environment and, at each antenna of the plurality of fixed antennas, receiving a plurality of messages from one or more aircrafts in response to one or more requests for data. To continue, data indicating location information for the one or more aircrafts is received and an intensity of each of the plurality of received messages at each of the fixed antennas is determined. In an embodiment, the “location information” may include two-dimensional (2D) location information and may also include altitude. Such an embodiment then determines orientation of each of the fixed antennas based on the location information and the determined intensity of each message of the plurality of received messages at each of the fixed antennas. In such an embodiment, the location information of the aircraft/target can be received by other means/antennae, such as by a separate ADS-B receiving radio.
Further, it is noted that while the aforementioned embodiment is described as receiving a plurality of messages and determining orientation based on intensity of each message of the plurality of received messages, embodiments are not so limited. For instance, in another embodiment, a single response is used to determine the approximate orientation of an antenna of the plurality, by determining, e.g., measuring, the intensity of the response on each antenna. In such an embodiment, orientation of an antenna is determined based upon the determined intensities of the message at the plurality of antennas. Such an embodiment may implement such functionality using a receiving radio for each antenna. However, another embodiment may use a single radio with a switch to select which antenna to use and, thus, in such an embodiment, a plurality of messages are used to estimate the orientation of each antenna.
It is noted that while embodiments are described herein as using a plurality of fixed antennas, embodiments are not so limited and embodiments may determine atmospheric conditions using a single fixed, e.g., non-rotating, antenna. In such an embodiment, the single antenna is used to send a request for data to an aircraft and, in turn, data is received from the aircraft in response to the request. This data received from the aircraft is then automatically processed in a manner determining an atmospheric condition.
Embodiments can be implemented in portable systems that can sample atmospheric conditions from aircrafts within range of the system, e.g., 100 miles. Embodiments can be deployed in any variety of environments and locations. Further, embodiments can provide data in near real-time time over cellular or satellite communications networks, amongst other examples, to consumers who want the data for their products or operations.
The following is a listing of data that the system may collect from aircraft. At a minimum, the data needed to estimate wind if presuming straight and level horizontal flight includes true airspeed, magnetic heading, true track angle, and ground speed. Truck track angle and groundspeed can be estimated from position reports. Local magnetic deviation is needed to obtain a true heading. Other data can enhance the calculation of atmospheric conditions. These data and the respective register that store them are the following. Register 0x50 stores roll angle, true track angle, ground speed, track angle rate, and true airspeed. Register 0x53 stores magnetic heading, indicated airspeed, Mach number, true airspeed, and altitude rate. Register 0x60 stores magnetic heading, indicated airspeed, Mach number, barometric altitude rate, and inertial vertical velocity. Register 0x44 includes wind speed, wind direction, static air temperature, average static air temperature, turbulence, and humidity. Register 0x45 includes turbulence, wind shear, microburst, icing, wake vortex, static air temperature, average static air temperature, average static pressure, and radio height.
A second aircraft 340 operates similar with respect to the fixed antenna 302. The aircraft 340 broadcasts ADS-B messages 348 that includes its location (latitude and longitude) and identifies the aircraft. After receiving the ADS-B messages 348, the system selects an antenna 304a-f that is determined to be pointing to the second aircraft 340 using the location of the fixed antenna 302, location of the aircraft from the ADS-B messages 308, and an orientation of the fixed antenna 302. In the example of
Table 1 below illustrates example results that can be calculated by the present system. While the database can be sorted in ways known to a person having ordinary skill in the art, Table 1 is one embodiment of such a sorting. Data from several aircraft is reported on a continuous basis and stored in the table, including the aircrafts location, time or recordation, and other data measured by the aircraft. These data can be correlated to windspeed, temperature, and pressure. From this information, weather conditions can be estimated in real time. A person having ordinary skill in the art can recognize that while a one-second time span is illustrated in
Client computer(s)/devices 50 and server computer(s) 60 provide processing, storage, and input/output devices executing application programs and the like. The client computer(s)/devices 50 can also be linked through communications network 70 to other computing devices, including other client devices/processes 50 and server computer(s) 60. The communications network 70 can be part of a remote access network, a global network (e.g., the Internet), a worldwide collection of computers, local area or wide area networks, and gateways that currently use respective protocols (TCP/IP, Bluetooth®, etc.) to communicate with one another. Other electronic device/computer network architectures are suitable.
In one embodiment, the processor routines 92 and data 94 are a computer program product (generally referenced 92), including a non-transitory computer-readable medium (e.g., a removable storage medium such as one or more DVD-ROM's, CD-ROM's, diskettes, tapes, etc.) that provides at least a portion of the software instructions for an embodiment. The computer program product 92 can be installed by any suitable software installation procedure, as is well known in the art. In another embodiment, at least a portion of the software instructions may also be downloaded over a cable communication and/or wireless connection. In other embodiments, the invention programs are a computer program propagated signal product embodied on a propagated signal on a propagation medium (e.g., a radio wave, an infrared wave, a laser wave, a sound wave, or an electrical wave propagated over a global network such as the Internet, or other network(s)). Such carrier medium or signals may be employed to provide at least a portion of the software instructions for the present invention routines/program 92.
The teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety.
While example embodiments have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the embodiments encompassed by the appended claims.
This application claims the benefit of U.S. Provisional Application No. 62/908,018, filed on Sep. 30, 2019. The entire teachings of the above application are incorporated herein by reference.
This invention was made with Government support under Grant No.: FA8702-15-D-0001 awarded by the U.S. Air Force. The Government has certain rights in the invention.
Number | Date | Country | |
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62908018 | Sep 2019 | US |