Patent Application
20070001920
1. Field of the Invention
Embodiments of the invention described herein pertain to the field of antenna positioning systems. More particularly, but not by way of limitation, these embodiments enable the positioning of antennas by way of a compact, lightweight, portable, self-aligning antenna positioner that is easily moved by a single user and allows for rapid setup and alignment.
2. Description of the Related Art
An antenna positioner is an apparatus that allows for an antenna to be pointed in a desired direction, such as towards a satellite. Many satellites are placed in geosynchronous orbit at approximately 22,300 miles above the surface of the earth. Other satellites may be placed in low earth orbit and traverse the sky relatively quickly. Generally, pointing may be performed by adjusting the azimuth and elevation or alternatively by rotating the positioner about the X and Y axes. Once oriented in the proper direction, the antenna is then best able to receive a given satellite signal.
Existing antenna positioners are heavy structures that are bulky and require many workers to manually setup and initially orient. These systems fail to satisfactorily achieve the full spectrum of compact storage, ease of transport and rapid setup. For example, currently fielded antenna systems capable of receiving Global Broadcast System transmissions comprise an antenna, support, positioner, battery, cables, receiver, decoder and PC. These antenna systems require over a half dozen storage containers that each require 2 or more workers to lift. Other antenna systems are mounted on trucks and are generally heavy and not easily shipped.
Embodiments of the invention provide a lightweight, collapsible and rugged antenna positioner for use in receiving low earth orbit and geosynchronous satellite transmissions. By collapsing the antenna positioner, it may be readily carried by hand or shipped in a compact container. For example, embodiments of the invention may be stored in a common carry-on bag for an airplane. The antenna positioner may be used in remote locations with manually assisted or automated setup and orientation. Embodiments of the invention may be produced at low cost for disposable applications. The apparatus can be scaled to any size by altering the size of the various components. The gain requirements for receiving any associated satellite transmission may be altered by utilizing more sophisticated and efficient antennas as the overall size of the system is reduced.
The movement of an antenna coupled with embodiments of the portable antenna positioner allows for low earth orbit, geostationary or geosynchronous location and tracking of a desired satellite. Since the slew rate requirements are small for geosynchronous satellites, the motors used in geosynchronous applications may be small.
One embodiment of the invention may be used, for example, after extending stabilizer legs and an adjustable leg to provide a stable base upon which to operate. In embodiments with a battery coupled with the apparatus, the antenna is extended and the system is aligned near a desired satellite at which time the system searches for and finds a desired satellite. The entire setup process can occur in rapid fashion. Another embodiment of the invention may utilize alternate mechanical positioning devices such as an arm that extends upward and allows for azimuth and elevation motors to adjust the antenna positioning. Another embodiment of the invention utilizes a smaller azimuth motor and limited range in order to lower the overall weight of the apparatus.
One or more embodiments utilize an adjustable leg or legs that may be motorized with for example a stepper motor. These embodiments are able to alter the effective elevation angle of a satellite relative to the apparatus so that the satellite is far enough away from the zenith to prevent “keyholing”.
In one embodiment of the invention, positioning of an associated antenna is performed by rotating positioner support frame in relation to a positioner base in order to set the azimuth. Setting the elevation is performed by altering the angle of the antenna mounting plate with respect to the positioner support frame. Since the elements are rotationally coupled to each other, rotation of the positioning arm alters the angle of the antenna mounting plate in relation to the positioner support frame. The motion of the antenna alters the angle of the antenna with relation to the positioner base. The resulting motion positions a vector orthogonal to the antenna mounting plate plane in a desired elevation and with the positioner base rotated to a desired azimuth, the desired pointing direction is achieved. Another embodiment of the invention makes use of an arm that comprises azimuth and elevation motors that are asserted in order to point an antenna to a desired pointing direction.
The pointing process is normally accomplished via powered means using the mechanisms described above. Various components are utilized by the apparatus to accomplish automated alignment with a desired satellite. A GPS receiver is used in order to obtain the time and the latitude and longitude of the apparatus. In addition, a tilt meter (inclinometer) or three axis accelerometer and magnetometer are be used to determine magnetic north and obtain the pointing angle of the antenna. By placing a group of sensors in both the electronics housing and antenna housing, differential measurements of tilt or magnetic orientation may be used for calibration purposes and this configuration also provides a measure of redundancy. For example, if the magnetometer in the positioner base fails, the magnetometer coupled with the antenna or in the antenna housing may be utilized. Such failure may be the result of an electronics failure or a magnetic anomaly near the positioner base. A low noise block down converter (LNB) along with a wave guide allows high frequency transmissions to be shifted down in frequency for transmission on a cable. One or more embodiments of the invention comprise a built-in receiver that enables the apparatus to download ephemeris data and program guides for channels. Motors and motor controllers to point the antenna mounting plate in a desired direction are coupled with at least one positioning arm in order to provide this functionality. Military Standard batteries such as BB-2590/M for example may be used to drive the motors. Any other battery of the correct voltage may also be utilized depending on the application. A keypad may be used in order to receive user commands such as Acquire, Stop, Stow and Self-Test. A microcontroller may be programmed to accept the keypad commands and send signals to the azimuth, elevation and optional adjustable leg motor in order to achieve the desired pointing direction based on a satellite orbit calculation based on the time, latitude, longitude, north/south orientation and tilt of the apparatus at a given time and the various orbital elements of a desired satellite. Optionally, a PC may host the satellite orbit program and user interface and may optionally transfer commands and receive data from the apparatus via wired or wireless communications.
By way of example an embodiment may weigh less than 20 pounds, comprise an associated antenna with 39 dBic gain, LHCP polarization, frequency range of 20.2 to 21.2 GHz and fit in an airplane roll-on bag of 14×22×9 inches. Embodiments of the invention may be set up in a few minutes or less and are autonomous after initial setup, including after loss and subsequent restoration of power. Although this example embodiment has a limited frequency range, any type of antenna may be coupled to the apparatus to receive any of a number of transmissions from at least the following satellite systems.
Any other geosynchronous or low earth orbiting satellite may be received by coupling an appropriate antenna to the apparatus. For example, a dish or patch array antenna may be coupled to the antenna mounting plate. An example calculation of the size of dish or patch array to achieve desired gains follows. An ideal one-meter dish, at 20 GHz, has a gain of 46.4 dBi. With 68% efficiency, it would have a gain of 44.7 dBi. A one-half meter diameter dish, therefore, would be 6 dB less, for a gain of 38.7 dBi. Certain patch arrays have efficiencies on the order of 30%, or about 3.6 dB below a dish of similar area. A patch array with a gain of 39 dBi would have an area of 0.474 square meters. A dish with a gain of 39 dBi would have an area of 0.209 square meters, or a diameter of 0.516 meters. For a patch array consisting of four panels, this implies each panel should have an area of 0.119 square meters, or 184 square inches. This is a square with sides of 13.6 inches. A panel that measures 20 in. by 12 in. has an area of 240 square inches (0.155 square meters). For the 4-panel system, the area is 960 square inches or 0.619 square meters; with a calculated gain of 40.2 dBi. Embodiments of the invention are readily combined with these example antennas and any other type of antennas. Optionally a box horn antenna may be coupled with the apparatus that is smaller and more efficient than a patch array antenna, but that is generally heavier and thicker. Additionally a wave guide fed slot array may be utilized.
Position Sensors used in embodiments of the invention allow for mobile applications. One or more accelerometer and/or gyroscope may be used to measure perturbations to the pointing direction and automatically adjust for associated vehicle movements in order to keep the antenna pointed in a given direction.
Some example components that may be used in embodiments of the invention include the Garmin GPS 15H-W, 010-00240-01, the Microstrain 3DM-G, the Norsat LNB 9000C the EADmotors L1SZA-H11XA080 and AMS motor driver controllers DCB-241. These components are exemplary and non-limiting in that substitute components with acceptable parameters may be substituted in embodiments of the invention.
In addition, one or more embodiments of the invention may comprise mass storage devices including hard drives or flash drives in order to record programs or channels at particular times. The apparatus may also comprise the ability to transmit data, and transmit at preset times. Use of solar chargers or multiple input cables allows for multiple batteries or the switching of batteries to take place. The apparatus may search for satellites in any band and create a map of satellites found in order to determine or improve the calculated pointing direction to a desired satellite. The apparatus may also comprise stackable modules that allow for cryptographic, routing, power supplies or additional batteries to be added to the system. Such modules may comprise a common interface on the top or bottom of them so that one or more module may be stacked one on top of another to provide additional functionality. For lightweight deployments all external stackable modules including the legs may be removed depending on the mission requirements.
Low power embodiments of the invention employ a limited range of motion in azimuth for the antenna positioner which allows the operator to be presented with an “X” in a box of the user interface. The operator sets the system to point within 60 degrees of a satellite, not 360 degrees. The system then prompts the user with the “X” which is on the left of the box if the operator should rotate the positioner base to the left and the “X” appears on the right side of the box if the operator is to rotate the positioner base to the right. Once the positioner base is within 30 degrees, the operator asserts a button and the system begins to acquire a satellite.
The system may employ tilt compensation so that even if the positioner base is not level, the scan includes adjustment to the elevation motor so that the scan lines are parallel to the horizon not to the incline on which the positioner base is situated. The three-axis accelerometer is used to provide tilt measurements in one or more embodiments of the invention.
The search algorithm utilized by the system may be optimized to search in azimuth and sparsely search in elevation. This is due to the fact that magnetic anomalies are more prevalent than gravitational anomalies. The system looks first in azimuth before elevation (preferential azimuth searching) since that is where the errors are likely found. For example in one embodiment, the search proceeds to do two horizontal scan lines first above the initial point before performing two horizontal scan lines below the initial point. In other words, after the signal peaks, it goes to peak then leaves the raster scan algorithm then uses a box peaking algorithm right and up to a corner, go to a left corner, down to corner and right bottom corner, e.g., 5 measurements. Then the system points to the strongest and does the four corner measurements again. When the four corners of the box have equal strength the antenna is positioned correctly and the search algorithm terminates.
The system also is capable of manually-assisted linear polarization setting. When aligning the third axis, that is aligning the antenna about an axis orthogonal to the antenna plane for linear polarization, the operator may be prompted for rotating the antenna manually. This allows for the elimination of a third motor although this motor is optional and may be employed in embodiments that are not power sensitive. The linear polarization axis is the least critical of all of the axial settings, so a little error is acceptable. In addition, the system without a linear polarization axis motor is lower weight.
The system may also be configured for bump detection and reacquisition. In this configuration, the system detects when the base or the antenna is bumped and reacquires the satellite. If the satellite signal is still high, then the system returns to a four corner boxing algorithm for example, otherwise the system goes back into scan mode. With two three-axis accelerometers, one on positioner base and one on antenna, both may be used for bump detection.
In order to further save power and time in acquiring satellites, the age of the two line element (TLEs) is taken into account in one or more embodiments of the invention. This is known as Clarke Belt Fallback. For ephemeris data or two line elements, fresh TLE data allows the system to point to the satellite accurately. However, in a couple of weeks, the TLE information is out of date, in a couple of months is actually quite inaccurate. For perfectly stationary satellites on the Clarke belt, i.e., equator, all the system has to know is the longitude to find one of these satellites. The satellites that move have a problem in that a fresh TLE is more accurate than a Clarke Belt longitude, but after 30 days the system falls back to the Clarke Belt longitude since it is more accurate after about this time span. Without fresh TLEs, acquisition takes more time and power, but by using the Clarke Belt Fallback, the system can still function.
In another power saving embodiment, the tracking of the satellites may switch between transponder signal and the beacon tracking signal output by a satellite. Beacons have a different frequency and are lower power than the data signal of the satellite. The beacons are also omni-directional so the system can find the satellite even if it is not pointed at the system at the time of acquisition. For small low power antennas, the beacon may be too small to detect, so if the data signal via the satellite transponder is on, it can be used to find and lock onto the satellite even if the beacon is too weak to detect.
Embodiments of the positioner base may make use of a hole in the base such that water and other environmental elements do not collect in the positioner base where the antenna positioning elements are stored. In this embodiment, a thermal well may be employed wherein all of the heat-making components situated in the positioner base, i.e., the electronics utilized by the system, dissipate heat. With regards to saving power and minimizing heat dissipation, algorithms that conserve power may be utilized in one or more embodiments of the invention. For example, when tracking a geosynchronous satellite, e.g., one that move in a figure eight pattern but remains relatively in one general area of the sky, the system can stop tracking the satellite at the top and bottom of the figure eight since motion is relatively slow there. The system can switch to more rapid tracking when the satellite is scheduled to move from the upper to the lower portion of the figure eight since the satellite motion is fast during this period. Conserving power as determined by two-line element (TLE) determined re-peak schedule allows for lower power dissipation and longer battery life. The system may utilize distributed I2C thermal sensors. The sensors may be placed on the electronics boards utilized by the system for example, so the computer can self-monitor the components.
The system allows for updating TLEs over the data link acquired. This allows for fresh TLEs to be used in locating and tracking satellites. The broadcasters may be configured to send down TLEs that the system uses to automatically update the local TLEs. After one month, the TLEs are considered old and if the system is powered up, then it may automatically update the TLEs if the acquired satellite is configured to broadcast them.
Some embodiments of the invention allow for a quick disconnect for the antenna panel. This allows for different satellites having entirely different frequency bands to be acquired with the system. This quick disconnect capability may be implemented by using double pins to hook the antenna to positioning arm. By releasing one antenna and attaching another antenna to the positioning arm, a different set of satellites in general may be acquired since satellites use various frequencies. Linearly polarized satellites, generally commercial satellites, may be acquired using a third rotational motor that allows for the antenna to rotate about the axis pointing at a satellite. For low power configurations, this allows for the user to be prompted to rotate the antenna until the strength of the signal is maximized. Low power embodiments therefore do not require a third axis motor.
One ore more embodiments of the invention provide an Integrated Receiver Decoder (IRD) slot. An IRD allows for set-top box functionality and may provide channel guide type functionality. The user interface to the IRD may include an IRD lock function that allows for feedback to the user for tracking qualification. If the IRD is integrated into the positioner base, the IRD can provide input to the positioner's computer or a visual display to the user to qualify the satellite as being identified as the desired satellite. In one small area of the sky, there may be five 5 commercial satellites in the field of view, so the system may prompt the user to select Next Satellite to continue looking for the correct satellite or the computer may automatically look to the next satellite.
Embodiments may utilize a “one button” or “no button” setup procedure. After opening the system and deploying the antenna and turning the power on, the system determines where it is and if pointed within a general direction of a satellite, requires no button pushes for the system to lock. The system can also perform the no button option so that after power loss and restore, the system re-acquires a satellite. This may occur with no intervention. One button operation may be utilized when the system is not rotated close enough to a satellite for example, where the system may prompt the user to rotate the base in one direction or the other and assert the acquire button. The prompt may include an “X” to the left or right in the LED screen to let the user know to turn the base clockwise or counterclockwise for example. The user interface may also present auto satellite options. For example, the first choice and second choice satellites may be presented to the user based on the band the system is configured for. Based on the location of the antenna on the planet, the user interface shows the operator the most likely satellite that is normally picked.
The system may also employ a failure contingency tree. For example if any portion of the system fails, the system may prompt the user via the display and allow the user to utilize the keyboard to respond to system requests for positioning the system, etc. For example, if the GPS or tilt fails, the system allows the operator to compensate for the error, prompts for entry on keyboard, of the GPS position or to acknowledge that the base is level. In short, the system is configured to ask the user for help if components break.
One or more embodiments of the invention allow for a sensor built into changeable antenna. For example, a 3 positioner accelerometer may be built into the changeable antenna panel. In addition, the antenna panel may be configured with memory in the changeable antenna that is used to notify the system what band the antenna is, so the system does not have to perform third axis rotation when not acquiring a satellite that uses linear polarization. For example, if acquiring a Ka band military satellite, the antenna panel is read and based on the fact that the Ka band antenna is being utilized, a whole set of the correct satellites in the correct band may be presented to the user via the user interface wherein some of all of the previous satellites receivable with the previous antenna are no longer presented. An additional tilt sensor may be utilized in the positioner base for crosschecking with antenna. Any redundant positioners may be placed throughout the system in order to provide redundancy and crosschecking capabilities.
The system has no loose parts and requires no tools. Since there are no parts to loose, the system is more robust. The system may include a camouflage bag that encapsulates the system and may be changed from desert to jungle to urban camouflage or black. Many different types of legs may be employed on the system depending on the terrain that the system is to be used in, including but not limited to legs with rubber bottoms, spikes or any other type of bottom, and the legs themselves may be of any type including telescoping or rigid or any other type.
Embodiments of the invention provide a self contained lightweight, collapsible and rugged antenna positioner for use in receiving and transmitting to low earth orbit, geosynchronous and geostationary satellites. In the following exemplary description numerous specific details are set forth in order to provide a more thorough understanding of embodiments of the invention. It will be apparent, however, to an artisan of ordinary skill that the present invention may be practiced without incorporating all aspects of the specific details described herein. Any mathematical references made herein are approximations that can in some instances be varied to any degree that enables the invention to accomplish the function for which it is designed. In other instances, specific features, quantities, or measurements well-known to those of ordinary skill in the art have not been described in detail so as not to obscure the invention. Readers should note that although examples of the invention are set forth herein, the claims, and the full scope of any equivalents, are what define the metes and bounds of the invention.
Positioner base 100 and positioner support frame 101 may be any geometrical shape although they are roughly shown as rectangular in
Collapsible antenna positioner 103 is further described below and in
Stiffness in collapsible antenna positioner 103 as shown in
Operation of embodiments of the invention comprise initial physical setup and powered acquisition of a desired satellite. Initial physical setup may comprise extending one or both of stabilizer legs 117 and 200 and in addition, optionally unfolding adjustable leg 115. As adjustable leg 115 may optionally comprise a powered stepper motor for altering the elevation of the apparatus when a satellite is near the zenith to eliminate keyholing. Alternatively, adjustable leg 115 may be manually adjusted. After any desired legs are deployed, pinch paddles 107 and 108 may be asserted in order to extend the associated axle up into the locked position on positioner arms 110 and 111. The opposing side of antenna 102 may then be lifted in order to lock the axle associated with release knob 112 in the extended position in positioner arm 109. When the axle associated with release knob 112 travels the full length of collapse groove 203, release knob 112 is in the locked position and must be asserted in order to release the associated axle and collapse the apparatus. With opposing sides of antenna 102 locked into position, motor release knob 113 is asserted in order to engage worm drive 441 and hence elevation motor 401. For connection based configurations not employing wireless communications, connecting desired communications links to a PC or other communications processor is performed. For configurations dependent upon an external computer, microcontroller 300 is optional so long as motor controller 303 comprises a communications port. As long as the external PC comprises the requisite drivers and satellite orbit calculation programs it may be substituted for microcontroller 300.
After physically deploying the apparatus, keypad port 116 may be accessed in order to operate keypad 320. Operations accessible from keypad 320 comprise acquire, stop, stow and test.
Asserting the acquire button and selecting a satellite initiates an orbital calculation that determines the location of a satellite for the time acquired via the GPS receiver. With the latitude and longitude acquired via GPS receiver 324 and the direction North and tilt of the apparatus measured via tilt sensor and magnetometer 106 all of the parameters required to point antenna 102 towards a desired satellite may be achieved. Positioner support frame 101 is rotated to the desired azimuth via drive hub 331, azimuth motor 330 and motor controller 303. Antenna 102 is elevated to the desired elevation via antenna mounting plate 222, plate mounts 402, 403 and 404, positioner arms 110, 111 and 109, worm drive 441 and elevation motor 401. Communications and control lines, not shown for ease of illustration, extend through a center hole in drive hub 331 to and from positioner base 100 and positioner support frame 101. These communications and control lines allow for the control of elevation motor 401 and receipt of down converted satellite signal via LNB 105 and measurement data from tilt sensor and magnetometer 106. For satellite locations near the zenith in the reference frame of the apparatus, an optional stepper motor at the end of adjustable leg 115 may be activated in order to shift the observed zenith of the apparatus away from the desired satellite near the observed zenith in order to prevent keyholing.
Asserting the stop button on keypad 320 stop whatever task the apparatus is currently performing. This button can be activated prior to activating the stow button. The stow button realigns positioner support frame 101 with positioner base 100 and performs a system shutdown. The test button performs internal system tests and may be activated with or without collapsible antenna positioner 103 deployed. These operations may be modified in certain embodiments or performed remotely by an attached PC or over a wireless network in other embodiments.
Using keypad 804, embodiments of the invention may utilize a “one button” or “no button setup” procedure. After opening the system and deploying the antenna in antenna housing 601 and turning the power on, the system determines where it is and if pointed within a general direction of a satellite, requires no button pushes for the system to lock. The system can also perform the no button option so that after power loss and restore, the system re-acquires a satellite. This may occur with no intervention. One button operation may be utilized when the system is not rotated close enough to a satellite for example, where the system may prompt the user to rotate positioner base 600 in one direction or the other and assert the acquire button. The prompt may include an “X” to the left or right in display 805 (for example an LED screen) to let the user know to turn positioner base 600 clockwise or counterclockwise for example. Display 600 may also present auto satellite options. For example, the first choice and second choice satellites may be presented to the user based on the band the system is configured for. Based on the location of the antenna on the planet, the user interface shows the operator the most likely satellite that is normally picked.
With regards to saving power and minimizing heat dissipation, algorithms may be employed by the computer housed in positioner base 600, that conserve power may be utilized in one or more embodiments of the invention.
Low power embodiments of the invention employ a limited range of motion in azimuth (e.g., azimuth motor 800 rotates only a portion of 360 degrees) for the antenna positioner which allows the operator to be presented with an “X” in a box of the user interface is display 805. The operator sets the system to point within 60 degrees of a satellite, not 360 degrees. The system then prompts the user with the “X” which is on the left of the box if the operator should rotate the positioner base to the left and the “X” appears on the right side of the box if the operator is to rotate the positioner base to the right. Once the positioner base is within 30 degrees, the operator asserts a button and the system begins to acquire a satellite. Wiring of the system is simplified by sub-360 degree rotation and weight is lowered as well.
The search algorithm utilized by the system may be optimized to search in azimuth and sparsely search in elevation. This is due to the fact that magnetic anomalies are more prevalent than gravitational anomalies. The system looks first in azimuth before elevation (preferential azimuth searching) since that is where the errors are likely found. For example in one embodiment, the search proceeds to do two horizontal scan lines first above the initial point before performing two horizontal scan lines below the initial point. In other words, after the signal peaks, it goes to peak then leaves the raster scan algorithm then uses a box peaking algorithm right and up to a corner, go to a left corner, down to corner and right bottom corner, e.g., 5 measurements. Then the system points to the strongest and does the four corner measurements again. When the four corners of the box have equal strength the antenna is positioned correctly and the search algorithm terminates.
In order to further save power, one or more embodiment may allow for the computer to perform tracking at uneven time intervals. For example, when tracking a geosynchronous satellite, e.g., one that move in a figure eight pattern but remains relatively in one general area of the sky, the system can stop tracking the satellite at the top and bottom of the figure eight since motion is relatively slow there. The system can switch to more rapid tracking when the satellite is scheduled to move from the upper to the lower portion of the figure eight since the satellite motion is fast during this period. Conserving power as determined by two-line element (TLE) determined re-peak schedule allows for lower power dissipation and longer battery life. The system may utilize distributed I2C thermal sensors. The sensors may be placed on the electronics boards utilized by the system for example, so the computer can self-monitor the components.
In another power saving embodiment, the computer housed in positioner base 600 performs tracking of the satellites in a manner that may switch between transponder signal and the beacon tracking signal output by a satellite. For example, beacons have a different frequency and are lower power than the data signal of the satellite. The beacons are also omni-directional so the system can find the satellite even if it is not pointed at the system at the time of acquisition. For small low power antennas, the beacon may be to small to detect, so if the data signal via the satellite transponder is on, it can be used to find and lock onto the satellite even if the beacon is too weak to detect.
In order to further save power and time in acquiring satellites, the age of the two line (TLEs) is taken into account in one or more embodiments of the invention by the computer housed in positioner base 600. This is known as Clarke Belt Fallback. For ephemeris data or two line elements (TLEs as used by Nasa), fresh TLE data allows the system to point to the satellite accurately. However, in a couple of weeks, the TLE information is out of date, in a couple of months is actually quite inaccurate. For perfectly stationary satellites on the Clarke belt, i.e., equator, all the system has to know is the longitude to find one of these satellites. The satellites that move have a problem in that a fresh TLE is more accurate than a Clarke Belt longitude, but after 30 days the system falls back to the Clarke Belt longitude since it is more accurate after about this time span. Without fresh TLEs, acquisition takes more time and power, but by using the Clarke Belt Fallback, the system can still function.
Some embodiments of the invention allow for a quick disconnect for the antenna panel or antenna itself in antenna housing 601. This allows for different satellites having entirely different frequency bands to be acquired with the system. This quick disconnect capability may be implemented by using double pins to hook the antenna or antenna housing 601 to positioning arm 801. By releasing one antenna and attaching another antenna to the positioning arm, a different set of satellites in general may be acquired since some satellites use various frequencies. Linearly polarized satellites, generally commercial satellites may be acquired using a third rotational motor that allows for the antenna to rotate about the axis pointing at a satellite. For low power configurations, this allows for the user to be prompted to rotate the antenna until the strength of the signal is maximized. Low power embodiments therefore do not require a third axis motor.
The system may also employ a failure contingency tree that is utilized by the computer housed in positioner base 600. For example if any portion of the system fails, the system may prompt the user via the display and allow the user to utilize the keypad 804 an attached keyboard to respond to system requests for positioning the system, etc. For example, if the GPS or tilt fails, the system allows the operator to compensate for the error, prompts for entry on keyboard, of the GPS position or to acknowledge that the base is level. In short, the system is configured to ask the user for help is components break.
The system may employ tilt compensation via the computer housed in positioner base 600 so that even if positioner base 600 is not level, the scan includes adjustment to elevation motor 802 so that the scan lines are parallel to the horizon as azimuth motor 800 turns so that the scan lines are not parallel to the incline on which the positioner base is situated. The three-axis accelerometer is used to provide tilt measurements in one or more embodiments of the invention.
The system also is capable of manually-assisted linear polarization setting. When aligning the third axis, that is aligning the antenna in antenna housing 601 about an axis orthogonal to the antenna plane for linear polarization, the operator may be prompted for rotating the antenna manually via display 805. This allows for the elimination of a third motor although this motor is optional and may be employed in embodiments that are not power sensitive. The linear polarization axis is the least critical of all of the axial settings, so a little error is acceptable. In addition, the system without a linear polarization axis motor is lower weight. An embodiment using a third axis motor for linear polarization may be manually moved if the motor controller for the linear polarization axis is detected as not working.
The system may also be configured for bump detection and reacquisition via the computer housed in positioner base 600. In this configuration, the system detects when the base or the antenna is bumped and reacquires the satellite. If the satellite signal is still high, then the system returns to a four corner boxing algorithm for example, otherwise the system goes back into half-scan mode where only half the elevation scan lines are checked while checking range of azimuth. With two three-axis accelerometers, one on positioner base 600 and one in antenna housing 601 or coupled with the antenna in antenna housing 601, both may be used for bump detection.
One or more embodiments of the invention allow for a sensor built into changeable antenna or changeable antenna housing 601. For example, a three-axis accelerometer may be built into the changeable antenna or changeable antenna housing 601. In addition, the antenna/housing may be configured with memory in the changeable antenna that is used to notify the system what band the antenna is, so the system does not have to perform third axis rotation when not acquiring a satellite that uses linear polarization. For example, if acquiring a Ka band military satellite, the antenna panel is read and based on the fact that the Ka band antenna is being utilized, a whole set of the correct satellites in the correct band may be presented to the user via display 805 wherein some of all of the previous satellites receivable with the previous antenna are no longer presented. An additional tilt sensor may be utilized in the positioner base for crosschecking with antenna. Any redundant positioners may be placed throughout the system in order to provide redundancy and crosschecking capabilities.
The system allows for updating TLEs over the data link acquired. This allows for fresh TLEs to be used in locating and tracking satellites. The broadcasters may be configured to send down TLEs that the system uses to automatically update the local TLEs. After one month, the TLEs are considered old and if the system is powered up, then it may automatically update the TLEs if the acquired satellite is configured to broadcast them. The download of ephemeris data or TLEs may occur before or after two months, or at any time that is convenient as determined by computer house in positioner base 600 or by the operator of the system for example.
One ore more embodiments of the invention provide an Integrated Receiver Decoder (IRD) slot in positioner base 600. An IRD allows for set-top box functionality and may provide channel guide type functionality. The user interface to the IRD may include an IRD lock function that allows for feedback to the user for tracking qualification. If the IRD is integrated into the positioner base, the IRD can provide input to the positioner's computer or a visual display to the user to qualify the satellite as being identified as the desired satellite. In one small area of the sky, there may be five 5 commercial satellites in the field of view, so the system may prompt the user to select Next Satellite to continue looking for the correct satellite via display 805 or the computer may automatically look to the next satellite.
After physically deploying the apparatus, keypad 804 as shown in
Asserting the acquire button and selecting a satellite initiates an orbital calculation that determines the location of a satellite for the time acquired via the GPS receiver. With the latitude and longitude acquired via GPS receiver and the direction North and tilt of the apparatus measured via tilt sensor and magnetometer all of the parameters required to point the antenna towards a desired satellite are achieved. Antenna housing 601 is rotated to the desired azimuth via azimuth motor 800. The antenna in antenna housing 601 is elevated to the desired elevation via elevation motor 802. The internal RSSI receiver may also be used in order to optimize the direction that the antenna is pointing to maximize the signal strength.
Asserting the stop button on keypad 804 stops whatever task the apparatus is currently performing. This button can be activated prior to activating the stow button. The stow button realigns positioner arm 801 with positioner base 600 and performs a system shutdown. The test button performs internal system tests and may be activated with or without antenna housing 601 deployed. These operations may be modified in certain embodiments or performed remotely by an attached PC or over a wireless network in other embodiments.
Thus embodiments of the invention directed to a Portable Antenna Positioner Apparatus and Method have been exemplified to one of ordinary skill in the art. The claims, however, and the full scope of any equivalents are what define the metes and bounds of the invention.
This application is a continuation in part of United States Utility patent application entitled “Portable Antenna Positioner Apparatus and Method”, Ser. No. 11/115,960, filed Apr. 26, 2005, the specification of which is hereby incorporated herein by reference, which takes benefit from United States Provisional Patent Application entitled “Portable Antenna Positioner Apparatus and Method”, Ser. No. 60/521,436 filed Apr. 26, 2004, which is hereby incorporated herein by reference.
This invention was made with Government support under F19628-03-C-0039 awarded by US Air Force, Department of Defense. The Government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 60521436 | Apr 2004 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11115960 | Apr 2005 | US |
| Child | 11412720 | Apr 2006 | US |
