Abstract:
A weather sensor system for gathering and transmitting weather related information. The system integrates information gathered from a barometer, temperature sensor, hygrometer, GPS, tilt sensor, and an anemometer. The anemometer assembly is a combined wind speed and direction sensor and radio antenna. The weather sensor data can be transmitted from a remote location and relay data to central collection point or network location.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    At present there are no low cost, easily portable weather sensors systems and/or weather stations available for military or similar unattended use. Many of the available weather stations are component systems. The closest match to the requirements of a low cost, portable weather station is a Kestral 4000. However, this device is a local device that does not relay weather data to an upstream central repository. Furthermore the Kestral 4000 is a hand held, and is therefore not intended for unattended operation, requiring the operator to manually point the device into the wind in order to measure wind speed. 
         [0002]    As exemplified in the above example of the Kestral 4000, one of the biggest hurdles to establishing an unattended gathering and transmission device to monitor weather is in the specific gathering of wind related information. Despite the fact that there are many prior devices and attempts, many devices have shortcomings that make their adoption impractical for the intended purpose. For example cup and vane anemometers are by far the most prevalent type of anemometer, but have drawbacks related to the moving parts. The weathervane device requires very free gimbals so as to allow the device to point accurately into the wind at very low wind speeds. As a result of its reliance on this mechanist element, the anemometer is not conducive to measuring gusts, and is subject to errors in measurement due to overshoot, oscillations that occur due to change in wind direction, and wind measurement even when the wind is not blowing. Moreover, because of the reliance on moving parts, cup and vane anemometers tend to wear and degrade in performance over time, and therefore are not optimal for unattended operation. 
         [0003]    Still another type, a sonic anemometer uses sound waves to measure wind direction and speed. These are a class of instruments that are typically used by research and other scientific organizations. These systems use the changes in the speed of sound as measure over a finite path. Whilst these instruments overcome the failings of the more prevalent cup and vane they cost considerably more to purchase and maintain. Also, the sonic devices tend to be very power hungry, so although they may be suitable for unattended operation, considerable cost and compensatory power mechanisms must be built into the device for continuous remote operation. 
         [0004]    Low maintenance, simplified anemometers are known, typically employing a vertical shaft sensor design with few moving parts. Such designs however, tend to be inaccurate and do not lend themselves to unattended use, or otherwise have complex detection methods, and therefore in design, they tend to be ineffective solutions to remote unattended use. In one example, Shoemaker (U.S. Pat. No. 7,117,735), a simple, single pickup wind drag force measurement system using a vertical rod is used. However, although this design addresses the cost threshold, the accuracy of measurement is modest. Moreover, the device is sensitive to inclinations of the device, and has no built in device as a compensatory mechanism correcting for the inaccuracies that would result if the device wasn&#39;t positioned in a true vertical. 
         [0005]    Gerardi (U.S. Pat. No. 5,117,687), another vertical shaft sensor design uses a sphere attached to a shaft. When the wind force moves the shaft, electromagnetic or optical sensors detect the deflection from the neutral position. The air data sensor uses a relative difference method to measure deflection using  4  orthogonally placed sensors in addition to two more sensors for complete 3-axis velocity measurements. One drawback to this design is the excessive use of strain gauges contributing to the overall complexity of the design. Moreover, this invention requires a counterweight to function in an inclination independent manner. 
         [0006]    Another difficulty with complex design is in the ability to transport the device. Portable wind sensors typically involve a weathervane structure that points a fan-based anemometer in the direction of the wind to measure wind speed. Other types of portable anemometers require the operator to point a fan-based device into the wind. These are generally unsuitable for unattended operation, suffering from inaccuracies in measurement and are generally less sensitive than more expensive designs. 
         [0007]    A need exists for a low cost, unattended weather data gathering device, to collect data related to temperature, relative humidity, barometric pressure and global position, as well as an accurate, low maintenance device for detecting wind related information. Moreover, the device should be easily portable, with a fully integrated transmission device to transmit data from a remote location to a central data repository. 
       SUMMARY OF THE INVENTION 
       [0008]    This invention relates generally to a portable weather sensor system and/or weather station, more specifically, to a system and method for unattended wind speed, wind direction, temperature, and relative humidity detection with a built-in global positioning device and integrated transmission device to measure and transmit gathered weather data to a central data repository. 
         [0009]    One embodiment of the present invention is a system that integrates aspects of a weather station by employing a barometric pressure sensor, temperature sensor, GPS receiver, a humidity sensor, digital compass, wind direction and wind speed sensor with a tilt sensor, along with a microprocessor system, battery, and an antenna for the datalink radio to relay data to a collection/processing point. The GPS provides world-wide unambiguous spatial, geographic position reporting. The barometer, temperature sensor, and hygrometer provide substantially complete weather data in a single integrated, portable unit. The digital compass indicates magnetic north relative to the sensor platform, and when combined with known magnetic deviations based on global position, can determine the direction of true north relative to the orientation of the weather station. This allows the weather station to provide true wind direction without regard to the rotation of the station base relative to true north. 
         [0010]    An element of the present invention is directed to an anemometer assembly that is a combined wind speed and direction sensor plus radio antenna. The wind sensor measures relative wind direction and speed without the use of moving parts and consumes very little power making it suitable for unattended operation. The main wind sensor is a vertical member that can be used as a radio antenna for a datalink. The data can be transmitted from a remote location to a central collection point or network location. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Preferred and alternative examples of the present invention are described in detail below with reference to the following drawings: 
           [0012]      FIG. 1  is a flow schematic of an exemplary unattended weather sensor system; 
           [0013]      FIG. 2-1  is a schematic top view illustrating the orientation of the sensors of the anemometer assembly of one embodiment of the present invention; 
           [0014]      FIG. 2-2  is a schematic top view of a tilt sensor; 
           [0015]      FIGS. 2-3  and  2 - 4  are schematic drawings of two sets of exemplary strain gauges; 
           [0016]      FIG. 3  is a cross-sectional and front view of an exemplary embodiment of the present invention; and 
           [0017]      FIG. 4  is a flow diagram depicting the operation of the weather sensor system. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0018]      FIG. 1  shows component parts of a weather sensor system  8  that includes weather sensors and system instruments. For example, weather sensors can include, but are not limited to: an anemometer assembly including an integrated radio antenna  10  (discussed in detail below) for measuring wind speed and direction and transmitting weather related data from the weather system  8 ; a barometric pressure sensor  60  (such as the MPX2102A absolute pressure sensor from Freescale Semiconductor); a humidity sensor  65  (which is preferably an HS1101LF by Humirel); and a temperature sensor and/or thermometer  70  (such as the DS7505 from Maxim Integrated Products). System instruments, can include for example, but are not limited to: a battery and/or other internal power supply  40 . Examples of the power supply  40  includes any suitable power source including a plurality of batteries. Magnetic orientation data is provided by a three-axis compass  45  which is preferably and HMC2043 by Honeywell) and a global positioning system (GPS) receiver  50  which is preferably a GlobalSat Technology EM-411 for receiving GPS location information from the weather sensor system  8 . The three-axis compass  45  indicates the direction of magnetic north and is unaffected by tilting of the compass. A datalink radio  17  which in one non-limiting embodiment can be a WiMax data link is a means for transmitting formatted weather sensor data and system instrument data to a weather data collection unit  90 . The weather data collection unit  90  in one exemplary embodiment is a matching datalink radio to datalink radio  17  attached to a personal computer for data storage and display. A tilt sensor and or meter  25  which in an non-limiting embodiment is an electrolytic tilt sensor such as the TrueTilt products from the Fredericks Company is also included. 
         [0019]    Also included are data processing system components including a power bus  80  to supply power to the devices in the weather sensor system  8  including the datalink radio  17 . Databus  87  provides a common interconnection between a microprocessor  24  and the weather sensor devices, datalink radio  17  and keyboard and display  100 . Program memory  85 ,  86  (which is typically a combination of Random-Access Memory  86  and Read-Only memory  85  and can be any suitable form) is a means for storing configuration and program information and other data, for example, the temporary storage of raw data from weather sensors (e.g. including data from  10 ,  60 ,  65 ,  70 ) and system instruments (e.g. including data from  25 ,  45   50 ). Formatted weather data may also be stored in Random Access Memory  86  prior to sending to datalink radio  17  for transmission. 
         [0020]    The microprocessor  24  can integrate data input from the weather sensor system  8  component parts, which can be queried at selected time intervals, for example at predetermined timed intervals or upon command. In one example a user can initiate the query of the weather sensor system  8  via a wireless connection using the datalink radio  17  or using local access (for example from the display and keyboard  100  of the user interface). In another embodiment, the weather sensor system  8  collects and transmits data from each of the weather sensor system  8  components according to a timed schedule. In either example, when the weather sensor system  8  receives a data request, or at the commanded time, can selectively power up, initiate weather data collection and transmit to the weather data to a weather data collection unit  90 , where all collected data can be correlated with that time period. The weather data can be, for example, either sensor measurement information (e.g. from the tilt sensor  25 ), or measurements from the hygrometer (humidity sensor)  65 , barometric pressure sensor,  60  and/or compass  45  or integrated measurements from a plurality of the sensors, (e.g calculated wind speed and direction data calculated from load cells  18 ,  19 ,  20 , and  21  with corrections for tilt based on measurements from tilt sensor  25  and corrected for orientation to true north based on data from 3-axis compass  45  and local magnetic deviation based on geographic location as determined by GPS receiver  50 ). Weather sensor and system instrument data can be formatted by the microprocessor  24  and transmitted as a data message using formats similar to, in this non-limiting example, the National Marine Electronics Association (NMEA) formats used to transmit position data between devices. 
         [0021]    A datalink radio  17  attached to the elongated vertical member plus radio antenna  16  (described further in  FIGS. 2-1 ,  3 ) of the anemometer assembly  10  is a means for transmitting formatted weather sensor and system instrument data to the weather data collection unit  90  for storage. The anemometer assembly as further described in  FIG. 2-1  and below, is in communication with the sub-system elements of the anemometer assembly  10 , and the sub-system elements of the weather sensor system  8 . The weather sensor system  8  is a means for processing wind speed and wind direction from the raw weather sensor data and is enabled to process correction data from the tilt sensor  25  ( FIG. 2-2 ) to adjust weather sensor data originating from the anemometer load sensors (see  FIG. 2-1 ). For example, if the anemometer assembly  10  is inclined at an angle when in the field, that inclination causes deviation of the elongated vertical member  16  from a true vertical position. Therefore, the tilt sensor  25  (see  FIGS. 2-2 ,  3 ) provides inclination adjustment data such that the load sensor deflection data can be adjusted to compensate for the deviation, thereby yielding accurate wind speed and wind direction data. The weather sensor system  8  can also include a means for presenting the weather sensor and system instrument data to a user in response to a user initiated query of the weather sensors and system instruments, for example a computer display and keyboard  100  with a graphic user interface. 
         [0022]      FIG. 2-1  and  FIG. 2-2  shows a schematic top view of an exemplary embodiment of a an anemometer assembly  10  of the present invention, that includes a plurality of opposing load sensors  18  and  19  located on an X-axis  30 , and load sensors  20  and  21  located on an Y-axis  30 , a sensor plate  12 ; a main wind sensor that is an elongated vertical member/antenna  16 ; an insulating bushing  15 , an antenna lead  13 , a tilt sensor  25  ( FIG. 2-2 ), and a datalink radio  17  having a microprocessor  24 . The tilt sensor  25  ( FIG. 2-2 ) is positioned on the sensor plate  12  to detect the angle of inclination of the device and generate correction data. The load sensors  18 - 21  are connected at corners of sensor plate  12  and a base structure  11  ( FIG. 3 ). The load sensors  18 - 21  are in signal communication with the microprocessor  24 . 
         [0023]    The sensor plate  12  is mounted on top of the plurality of load sensors  18 ,  19 ,  20 ,  21  preferably at 90 degree angles to each other, each load sensor  18 ,  19 ,  20 ,  21  positioned at a corner of the sensor plate  12 , each load sensor  18 ,  19 ,  20 ,  21  is positioned to sense a load in a direction unique from that of the other. Opposing load sensors  18  and  19 , in this example, are along the X axis  30  in relationship to the sensor plate  12 ; and opposing load sensors  20  and  21  are located along a Y axis  35 . Each load sensor  18 ,  19 ,  20 ,  21  makes indirect contact with the elongated vertical member  16  through the sensor plate  12 . Each load sensor  18 ,  19 ,  20 ,  21  detects and measures a load force associated with deflections of the elongated vertical member  16  and transmits any such measured deflection data to the microprocessor  24 . 
         [0024]    The elongated vertical member  16  is also a radio antenna for transmitting the formatted weather sensor data generated by weather sensor system  8  by the local datalink radio  17 , such as, but not limited to, a WiMax data radio to the weather data collection unit  90  (See  FIG. 3 ). The elongated vertical member  16  is substantially freestanding and designed to be physically deflected in the direction of any wind flow when placed in such a wind flow stream. The amount of deflection is proportional and directional to the velocity and direction of any such wind flow. The insulating bushing  15 , positioned at an opening in the sensor plate  12 , insulates the elongated vertical member  16  from the sensor plate  12  allowing the elongated vertical member  16  to transmit radio signals without interference. The elongated vertical member  16  is secured to the insulating bushing  15  and the insulated bushing  15  is secured to the sensor plate  12 . The antenna lead  13  connects the elongated vertical member/antenna  16  to the datalink radio  17 . 
         [0025]    The microprocessor  24  converts load sensor  18 - 21  voltage to wind speed. Wind speed in each axis is then corrected for tilt in the sensor plate  12 , and the corrected wind speeds in each axis are converted to resultant wind speed and direction. The microprocessor  24  then corrects the wind direction for rotation of the sensor plate  12  using data from the 3-axis magnetic compass  45 . The magnetic direction of the wind is then compensated for magnetic deviation by magnetic deviation data derived from the geographic location of the weather station as determined by GPS receiver  50 . The resulting wind direction is expressed relative to true (geographic) north. Microprocessor  24  formats the wind and weather data and sends it to datalink radio  17  where it is transmitted to weather data collection unit  90  ( FIG. 3 ). 
         [0026]    The tilt sensor  25  ( FIGS. 2-2 ,  3 ) produces tilt data that is used to correct for variations in inclination of the anemometer assembly  10 , and accurately calibrate the force on the elongated vertical member  16 . For example, a semi-conductor MEMS (micro electronic machined semiconductor) device or an electrolytic tilt sensor (e.g. TrueTilt products from the Fredericks Company) can be used to provide for the correction details. The force due to inclination of elongated vertical member  16  from true vertical acts as if the mass of elongated vertical member  16  is located at the midpoint of the element. The force on the sensor plate  12  due to inclination from vertical is equal to the Sine of the angle of inclination from vertical multiplied by the length of elongated vertical member  16  divided by the distance between opposing load cells. To correct for inclination errors, this force is subtracted from the measured force due to wind to determine the true wind induced force on elongated vertical member  16 . 
         [0027]    Turning to back to  FIG. 2-1  and referring to  FIGS. 2-3  and  2 - 4 , opposing load sensors  18  and  19 ,  20  and  21  form two legs of a Wheatstone bridge circuit. In one preferred orientation of the load sensors  18 ,  19 ,  20 ,  21  is at 90 degree angles apart from each other to provide orthogonal force measurements that can be used with vector analysis to determine wind direction. The total force applied to the elongated vertical member  16  can be resolved by vector addition of the individual component forces. 
         [0028]    In  FIG. 2-3 , a first Wheatstone bridge circuit  18 - 19  includes a high side of an input voltage V IN  is connected to a first side of the first load cell  18   -L  and resistor R AX . The low side V IN  is connected to a first side of a second load cell  19   -L  and resistor R BX . A voltage out V OUT  is sampled across a node of the second sides of R AX  and R BX  and a node of the second sides of the load cells  18   -L ,  19   -L . A change in the resistance value of the load cells  18   -L ,  19   -L  correlates to an applied strain. Because the orthogonal wind axis, i.e. axis along which the wind is blowing, can act as a pivot point, the particular load cells used for this application preferably respond to both tensile and compressive forces. 
         [0029]    For example, the standard arrangements as shown in the schematic diagrams  FIGS. 2-3  and  2 - 4 , can have two resistive strain gauges and two fixed or unstrained resistors to measure aerodynamic forces in each in each of the two orthogonal directions: εTx is the total strain in along the X axis  30 , and εTy is the total strain along the Y axis  35 . Total strain for each of the two orthogonal directions can be given by the equations: 
         [0000]      ε Tx=εRAx−εrBx+εR 18−ε R 19   (1) 
         [0000]      ε Ty=εRAy−εrBy+εR 20−ε R 21   (2) 
         [0030]    Where εTx=total strain in the x direction; 
         [0031]    εTy=total strain in the y direction 
         [0032]    εRAx=total strain on resistor Ax in the x direction 
         [0033]    εRAy=total strain on resistor Ay in the y direction 
         [0034]    εRBx=total strain on resistor Bx in the x direction 
         [0035]    εRBy=total strain on resistor By in the y direction 
         [0036]    εR 18 =strain on element  18  in the x direction 
         [0037]    εR 19 =strain on element  19  in the x direction 
         [0038]    εR 20 =strain on element  20  in the y direction 
         [0039]    εR 21 =strain on element  21  in the y direction 
         [0040]    Ax, Ay, Bx and By are fixed resistors or unstrained resistance strain gauges. 
         [0041]    Signals generated by the load sensors  18 ,  19 ,  20 ,  21  include, for example, static strain due to the drag of the elongated vertical member  16  and are proportional to the square of the wind velocity. The generated signals from the load sensors  18 ,  19 ,  20 ,  21  are sent to the microprocessor  24 . The microprocessor  24  simultaneously receives the generated signals from at least two load sensors  18 ,  19 ,  20 ,  21 . Inclination of the sensor plate  12  from perfectly flat introduces load signal in load sensors  18 ,  19 ,  20 , and  21  that would appear as wind if not corrected for. Inclination of sensor plate  12  is measured by tilt sensor  25 . The tilt data generated by tilt sensor  24  is used by microprocessor  24  to correct the force measurements from load sensors  18 ,  19 ,  20 , and  21  for errors due to inclination of the sensor plate  12 . The tilt sensor  24  can be calibrated prior to operation if it is not self calibrating. A correction coefficient relating tilt angle to force on the load sensors ( 18 ,  19 ,  20 ,  21 ) is dependent on the height and weight of elongated vertical member  16 . 
         [0042]    In a preferred embodiment, a rigid material is used for the elongated vertical member providing for simple moment arm calculations (i.e. moment calculated by force multiplied by the lever arm length) to establish the correction factor for tilt. If, for example, the elongated vertical member  16  can bend substantially in the wind because of inherent flexibility, calculation of wind velocity becomes significantly more complex, as the moment arm of the sensing element is no longer a second-order function of wind velocity at high wind speeds, A vector wind speed algorithm, for example as discussed above (See Equations 1 and 2), is carried out by a microprocessor unit  24  ( FIG. 3 ) to solve the load force equation for velocity in each axis  30 ,  35 , applying the proper calibration coefficients to the drag for (as described in Equation 3) and tilt sensor  25  ( FIGS. 2-2 ,  3 ) data. The microprocessor  24  corrects the load sensor voltage data for tilt and converts the corrected load sensor voltage data to wind speed along each axis. Wind speed in each axis is then converted to resultant wind speed and relative direction. The wind direction and speed is then formatted by microprocessor  24  and sent to datalink radio  17  for transmission. 
         [0043]      FIG. 3  is a cross-sectional view of an anemometer assembly  10  along an X-axis  30 , showing two opposing load sensors  18 ,  19 , a rigid mounting platform  11 , the sensor plate  12 , and further incorporating some of the features of the present invention. 
         [0044]    The anemometer assembly  10  as described above, measures the speed or velocity and direction of wind flowing over a surface and includes the sensor plate  12  having a means, such as an opening, for being connected to the elongated vertical member  16 . The sensor plate opening in conjunction with the insulating bushing  15  is a means for securing the elongated vertical member substantially perpendicularly within any such wind flow. The elongated vertical member  16  is connected to and extends perpendicularly through the sensor plate  12 , through the insulating bushing  15 , connecting with the antenna lead  13  and the datalink radio  17 . 
         [0045]    The four load sensors  18 - 21  are mounted on a rigid platform  11 . The rigid platform  11  and the sensor plate  12  are separated by a gap, such that the rigid platform is parallel to and underneath to the sensor plate  12 . The elongated vertical member  16  is secured to the rigid platform and extends substantially perpendicularly from the rigid platform with the elongated vertical member being substantially freestanding and designed to be physically deflected when placed in a wind flow. The antenna lead is substantially protected from wind disturbance by its position within the space between the sensor plate  12  and the rigid platform  11 . 
         [0046]    The elongated vertical member  16  is preferably made of stainless steel or some other suitably rigid, conductive material with a height between approximately 14 inches to 36 inches and a ratio of height to diameter of approximately 30:1 for sensing wind speeds from approximately 10-120 mph. The dimensions of the elongated vertical member  16  are chosen to optimize the range of wind speeds detectable. For example if the elongated vertical member  16  is too long and/or too thin it will not withstand strong winds. On the other hand if the elongated vertical member  16  is too thin and/or too short it will not be responsive to low wind velocities. With these considerations in mind, the elongated vertical member  16  is selected to provide a desirable range of strain values. Preferably an elongated vertical member  16  will be in the range of 0.35-0.75 inches in diameter. 
         [0047]    The force (F) acting on the elongated vertical member  16  is proportional to the square of the wind speed (V); signal generated from the load sensors increases with increased wind velocity. By measuring force (F) while knowing the other parameters (including the dimensions of the elongated vertical member  16 , the velocity is derived by the equation: 
         [0000]        V=[ 2 F/C   d  ρ 1  d]   1/2    (3) 
         [0048]    where C d  is the drag coefficient of the elongated vertical member; ρ is the density of the fluid (air), 1 and d are the length and diameter of the elongated vertical member, and V is the free stream velocity of the wind. Because the force due to the wind on the mounted elongated vertical member  16  is measured in two axes (X  30  and Y  35 ), the anemometer assembly  10  measures the vector components of the local wind. Therefore using a rectangular to polar coordinate system conversion, both wind speed and direction can be inferred. 
         [0049]    The local microprocessor  24  processes the raw wind sensor measurement data information and uses tilt sensor  25  data to calculate the correct wind speed and direction. Magnetic compass  45  is used to determine the magnetic orientation of weather station including weather sensor system  8  so that microprocessor  24  can calculate the wind direction relative to magnetic north regardless of the orientation of weather station. The magnetically oriented wind direction is then corrected for magnetic deviation by using known magnetic deviation from true north based on the geographic location of weather station as determined by GPS unit  50 . The wind direction and speed relative to true north, temperature, humidity, barometric pressure, and weather station geographic location information is then formatted for transmission by the datalink radio  17  to a weather data collection unit  90 , including a means to store and display the received weather data. The elongated vertical member  16  is also a radio antenna for transmitting the data to the weather data processing unit  90 . An antenna lead  13  connects the elongated vertical member  16  to the datalink radio  17 . 
         [0050]    The weather data collection unit  90 , which can be, but is not limited to, a central computer enabled data repository that receives the formatted signals from the datalink radio  17  and local microprocessor  24  and stores this information for later retrieval. 
         [0051]    Wind speed is derived from manipulation of the raw data, and equal to the square root of the sum of the square of the wind speeds along the two axes as detected by opposing load sensors. Wind direction is derived from values detected by the load sensors, and is calculated as the inverse tangent of the ratio of the wind speed in the Y-axis  35  to the wind speed in the X-axis  30 . 
         [0052]    Turning to  FIG. 4  a flow chart illustrates a system  150  for measuring and transmitting weather data as practiced according to one embodiment of the invention. In operation at a Block  155  the weather sensor system  8  can be queried for weather sensor and system instrument data, which can be, for example at an automatic and scheduled time interval, or by an initiated query by a remote user. At a Block  160  weather sensor data, including barometric pressure, humidity, temperature, global position, tilt, and wind speed and direction is generated and sent to the microprocessor  24 . At block  165 , the GPS is interrogated for geographic location and magnetic compass  45  is interrogated for magnetic orientation of the weather sensor system  8 . Next at a Block  170 , the wind direction is corrected for orientation of the weather sensor system  8  to magnetic north and further corrected for magnetic deviation from vertical to provide wind direction relative to true (geographic) north. Next at a Block  175 , the microprocessor  24  stores the weather data. At block  180 , the stored weather data is formatted and transmitted via the datalink radio  17  to a weather data collection unit  90 , which can be, for example, a central data repository computer. The elongated vertical member  16  is also the radio antenna for the datalink radio  17 . The insulating bushing  15  positioned at an opening in the sensor plate  12 , insulates the elongated vertical member  16  from the sensor plate  12  allowing the elongated vertical member  16  to transmit radio signals without interference. 
         [0053]    At block  185 , the transmitted weather data is received and stored in weather data collection unit  90 . At block  190 , the weather data in the central repository is retrieved for presentation or analysis. Weather data collection unit  90  includes means for further analysis of weather data and display of weather data already stored. 
         [0054]    While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. For example, simple software modifications enable this, allowing for updates to keep this invention useful for the foreseeable future; and a wide variety of materials can be used for the component parts and a variety of load cells and tilt sensors can be used without departing from the spirit of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.