Patent Publication Number: US-7708206-B2

Title: Irrigation unit including a nozzle having greater accuracy and improved adjustment properties

Description:
REFERENCE TO RELATED APPLICATION 
   This application claims priority on copending U.S. application Ser. No. 10/762,134 filed on Jan. 20, 2004 and entitled “IRRIGATION UNIT INCLUDING A POWER GENERATOR”. As far as is permitted, the contents of U.S. application Ser. No. 10/762,134 are incorporated herein by reference. 
   BACKGROUND 
   Water is becoming an increasingly valuable and scarce commodity both in the United States and abroad. In particular, extreme drought conditions are common in arid regions such as the desert southwestern United States, although a decreased level of precipitation and resulting low water supplies can occur just about anywhere at various times. To compound matters, substantial amounts of water are squandered due to inefficient and ineffective conventional irrigation systems, for a variety of reasons. 
   For example, typical irrigation units distribute water in a full round, half-round, quarter-round or an adjustable-type circular pattern. Thus, no matter how the irrigation units are arranged, obtaining consistent water coverage over a rectangular watering area is difficult or impossible. Watering normally occurs to prevent brown spots, resulting in over watering in basically all other areas. In fact, in order to ensure that all areas are adequately irrigated, overlapping spray regions occur, which can result in certain areas receiving 300% or more of the necessary amount of water. 
   Further, runoff from elevated areas such as mounds, slopes or hills causes ponding in lower areas, which can ultimately result in the higher areas absorbing an insufficient amount of water, while the lower areas are being saturated with water. Thus, watering occurs indiscriminately whether certain areas of the ground are wet or dry. In addition, in hot, windy conditions, water has a higher evaporation rate and may not actually reach the ground in the intended location, if at all. Moreover, different types of grass, trees or other foliage require varying levels of irrigation. These problems are exacerbated when the watering area is irregularly-shaped and includes areas that do not require water, such as walkways, driveways, fountains, ponds or other surfaces or features. 
   Consequently, a significant quantity of water is routinely wasted, resulting in higher water bills and lower reservoirs. Further, the cost for pumping large amounts of water can result in increasingly high electrical expenses. In large turf areas, such as on golf courses, excessive and inefficient watering can give rise to enormous costs to the owner, thereby making maintaining a lush, green golf course prohibitive. 
   Further, turf and soil maintenance is significantly increased due to the deposits of minerals, chemicals and salts that are left in the soil from irrigation. This is particularly a problem where reclaimed water having a high total dissolved solids (TDS) content is used for irrigation. These minerals, chemicals and salts can reduce absorption of the water into the soil, can change the pH of the soil, and/or can make the soil excessively salty, inhibiting growth of vegetation in the soil. 
   SUMMARY 
   The present invention is directed toward an irrigation unit for irrigating an area with a fluid from a fluid source. In one embodiment, the irrigation unit includes a housing, a nozzle, a first mover and a second mover. The nozzle is secured to the housing and is in fluid communication with the fluid source. The first mover rotates the nozzle about a first axis, and the second mover rotates the nozzle about a second axis that is different than the first axis. In one embodiment, the second axis is substantially perpendicular to the first axis. 
   In another embodiment, at least a portion of the housing can movably extend along the first axis. The second mover can rotate the nozzle about the second axis based at least partially upon a pressure of the fluid within the housing and/or based at least partially upon position of the area relative to the nozzle. Further, the second mover can oscillate the nozzle about the second axis. In an alternative embodiment, the rotation of the nozzle about the second axis is at least partially based upon at least one of a wind direction and a wind speed near the nozzle. 
   The present invention is also directed toward a method for irrigating an area with a fluid from a fluid source. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which: 
       FIG. 1A  is a top plan view of a hole of a golf course and an automated irrigation assembly having features of the present invention; 
       FIG. 1B  is a detailed top plan view of a portion of the hole illustrated in  FIG. 1A , including a first embodiment of a plurality of irrigation regions; 
       FIG. 1C  is a detailed top plan view of a portion of the hole illustrated in  FIG. 1A , including a second embodiment of a plurality of irrigation regions; 
       FIG. 1D  is a detailed top plan view of one of the irrigation regions illustrated in  FIG. 1C , including a plurality of irrigation subregions; 
       FIG. 1E  is a detailed top plan view of a portion of the hole illustrated in  FIG. 1A , including a third embodiment of a plurality of irrigation regions; 
       FIG. 1F  is a detailed top plan view of one of the irrigation regions illustrated in  FIG. 1E , including a plurality of irrigation subregions; 
       FIG. 2A  is a perspective view of an irrigation unit having features of the present invention illustrated in a retracted position; 
       FIG. 2B  is a perspective view of the irrigation unit illustrated in  FIG. 2A  in an extended position; 
       FIG. 2C  is a top plan view of the irrigation unit illustrated in  FIG. 2A ; 
       FIG. 2D  is a cut-away view of a first section of the irrigation unit illustrated in  FIG. 2A ; 
       FIG. 2E  is a top plan view of an alternative irrigation unit having features of the present invention; 
       FIG. 2F  is a front plan view of a third section of the irrigation unit illustrated in  FIG. 2A ; 
       FIG. 2G  is a cut-away view of the third section of the irrigation unit taken on line  2 G- 2 G in  FIG. 2F ; 
       FIG. 2H  is a cut-away view of the third section of the irrigation unit taken on line  2 H- 2 H in  FIG. 2F ; 
       FIG. 2I  is a perspective view of another embodiment of the irrigation unit; 
       FIG. 2J  is a perspective view of yet another embodiment of the irrigation unit; and 
       FIG. 3  is a simplified block diagram showing the electrical components of a main control system in communication with the irrigation units in accordance with the present invention. 
   

   DESCRIPTION 
   The present invention provides an automated irrigation system (also referred to herein simply as “irrigation system”) and method for selectively irrigating a specific area. The configuration and type of area with which the irrigation system provided herein can be used can vary widely. For ease of understanding, a portion of a golf course is described herein as a representative area that can be irrigated with the present invention. However, it is recognized that any area in need of irrigation, regardless of size or location, can benefit from use with the irrigation system provided herein. For example, the irrigation system  10  can be used for irrigating a lawn, a sports field, agricultural crops and other vegetation, a cemetery, a park, or any other suitable area. 
   A number of Figures include an orientation system that illustrates an X axis, a Y axis that is orthogonal to the X axis, and a Z axis that is orthogonal to the X and Y axes. It should be noted that these axes can also be referred to as the first, second and third axes. 
     FIG. 1A  is a top plan view of an automated irrigation system  10  having features of the present invention installed on a golf course  12  (only a portion of the golf course  12  is illustrated for clarity). More specifically, the portion of the golf course  12  illustrated in  FIG. 1A  includes one golf hole  14 , although it is recognized that any number of golf holes  14  can be included in the golf course  12 . The typical golf hole  14  can include a plurality of existing features, such as (i) one or more tee areas  16 A, (ii) one or more trees, bushes or other plants (also referred to herein as “vegetation”  16 B), (iii) one or more areas of relatively short turf growth (also referred to herein as a “fairway”  16 C), (iv) one or more areas of longer turf growth (also referred to herein as “rough”  16 D), (v) a green  16 E, (vi) one or more sand traps  16 F, (vii) one or more natural or manmade water features  16 G such as lakes, streams, ponds, waterfalls, etc., (viii) a cart path  16 H or vehicle access road, (ix) a natural or manmade rock formation  16 I, and/or (x) walkways  16 J, paths or bridges, as non-exclusive examples. As used herein, the “existing features” can be comprised of manmade and/or natural features. 
   In one embodiment, one or more of the water features  16 G can serve as a fluid source  18  that uses a pump (not shown) or other suitable means to supply irrigation fluid  19  for the irrigation system  10 . Alternatively, the fluid source  18  can be a water tank or other receptacle (not shown), or an offsite water source (not shown), such as a lake, river, stream or the like. Still alternatively, the fluid source  18  can include water from a municipal or reclaimed water source, as non-exclusive examples. 
   The type of irrigation fluid  19  utilized can vary according to the type of ground cover and the features  16 A-J on the golf course  12 . The irrigation fluid  19  can be (i) water, (ii) reclaimed water, (iii) waste water, (iv) water with amendments, additives, chemicals, and/or pesticides, or (v) another suitable type of fluid, as non-exclusive examples. 
   In one embodiment, the irrigation system  10  precisely provides irrigation fluid  19  to those features that normally would require irrigation fluid  19 , such as the tee areas  16 A, the vegetation  16 B, the fairway  16 C, and the green  16 E. On the other hand, in one embodiment, the irrigation system  10  inhibits and/or minimizes the application of the irrigation fluid  19  on various other features, such as the sand traps  16 F, the water features  16 G, the cart paths  16 H, the rock formations  161  and the walkways  16 J. As provided herein, the irrigation system  10  can selectively and efficiently distribute the irrigation fluid  19  to specific areas, while reducing or eliminating the application of irrigation fluid  19  to other areas. 
   Additionally, the rough  16 D may require irrigation fluid  1 . 9  depending upon the type of grass or other planting material included in the rough  16 D and the desired condition of such grass or vegetation. For instance, if the rough  16 D includes grass areas, irrigation fluid  19  may be required. However, if the rough  16 D includes bark, mulch, dirt, sand or other ground cover that would not require irrigation fluid  19 , the irrigation system  10  reduces or eliminates applying irrigation fluid  19  to those areas, as described in greater detail below. With this design, a decreased quantity of irrigation fluid  19  is required, thereby lowering water costs. Further, inhibiting watering of cart paths  16 H and walkways  16 J decreases the likelihood of (i) a golf cart losing traction, or (ii) the creation of a slip and fall hazard for a golfer, as examples. 
   The irrigation system  10  illustrated in  FIG. 1A  includes (i) a plurality of spaced apart irrigation units  20 , each having a unit power source  230  (illustrated in  FIG. 2D ), (ii) a main control system  22 , and (iii) an auxiliary power source  24 . As provided in greater detail below, the irrigation units  20 , the main control system  22  and the auxiliary power source  24  cooperate to distribute irrigation fluid  19  from one or more of the fluid sources  18  to specific regions of the golf course  12 . In an alternative embodiment, and as explained in detail below, no auxiliary power source  24  is required. In one embodiment, the auxiliary power source  24  can be in electrical communication with the main control unit  22  and/or the irrigation units  20 . 
   In the embodiment illustrated in  FIG. 1A , the main control system  22  can be in electrical communication with one or more of the irrigation units  20  via a power line  26  and/or a data line  28 . In an alternative embodiment, a single line can operate as both the power line  26  and the data line  28 . Still alternatively, either or both of the power or data lines between the main control system  22  and the individual irrigation units  20  are not necessary. 
   The arrangement and positioning of the irrigation units  20  can vary depending upon the configuration and the water requirements of the features  16 A-J on the golf course  12 . Further, because the irrigation system  10  provided herein can be retrofitted for use with an existing irrigation system (not shown) as provided in greater detail below, the positioning of the irrigation units  20  described herein may also be at least partly dependent upon the location of existing irrigation units (not shown) to be retrofitted, although this is not a requirement of the present invention. 
   In the embodiment illustrated in  FIG. 1A , the irrigation units  20  are arranged in a pattern that includes one or more rows. Alternatively, the irrigation units  20  can be arranged in a different pattern, or can be randomly placed on the golf course  12 . 
     FIG. 1B  is an enlarged view of the dashed rectangular area  1 B illustrated in  FIG. 1A . In the embodiment illustrated in  FIG. 1B , the golf hole  14  includes a plurality of irrigation regions  30  (illustrated with grid lines  31 ). Although the irrigation regions  30  illustrated in  FIG. 1B  are substantially square, any shape can be used for the irrigation regions  30 . For example, the geometry of each irrigation region  30  can be circular, oval, rectangular, triangular, trapezoidal, hexagonal, or can have another suitable configuration. Further, the golf hole  14  can utilize a combination of geometries for the irrigation regions  30 . Additionally, the size of each irrigation region  30  can be varied. In one embodiment, each irrigation region  30  can be a square that is approximately 80 feet×80 feet. However, the irrigation region  30  can have a larger or smaller area, depending upon the design requirements of the irrigation units  20 . In alternative embodiments, the irrigation region  30  can be 25 feet×25 feet, 40 feet×40 feet, 60 feet×60 feet, or 100 feet×100 feet, as non-exclusive examples. 
   In this embodiment, each irrigation region  30  is serviced by a corresponding irrigation unit  20 . Further, in the embodiment illustrated in  FIG. 1B , the irrigation regions  30  and the irrigation units  20  within the irrigation regions  30  are aligned in substantially straight rows along the golf hole  14 , and are connected with subterranean irrigation lines  32  (some representative irrigation lines  32  are shown in phantom in  FIG. 1B ) to the fluid source  18 . 
   As an overview, in one embodiment, each irrigation unit  20  is programmed to precisely apply the appropriate quantity of irrigation fluid  19 , as necessary, to only those portions of the corresponding irrigation region  30  that require irrigation fluid  19 . Additionally, in one embodiment, should the irrigation fluid  19  requirements change over time within the irrigation region  30 , the irrigation unit  20  will accordingly modify the quantity of irrigation fluid  19  applied within the irrigation region  30 , as provided herein. 
   The irrigation system  10  can use existing irrigation lines  32  in the event of a retrofit. Alternatively, the existing irrigation lines  32  can be abandoned, or a portion of the existing irrigation lines  32  can be utilized. Still alternatively, new irrigation lines  32  can be installed below the surface of the ground in any pattern necessary to effectuate the intent of the present invention. The irrigation lines  32  can be formed from plastics such as polyvinylchloride (PVC), various metals, or any other suitable materials. 
     FIG. 1C  is another embodiment of a portion of a golf hole  14 C. In this embodiment, the irrigation units  20  are not aligned in rows. Instead, at least some of the irrigation units  20  can be offset along either the X axis, the Y axis, or along both the X and Y axes. Stated another way, the irrigation units  20  can be specifically positioned to increase the effective watering area of each irrigation unit  20 . As used herein, the effective watering area of one irrigation unit  20  within one irrigation region  30  is defined as the percentage of the surface area within the irrigation region  30  that requires irrigation fluid  19 . Thus, an irrigation unit  20  that is positioned immediately adjacent to the water feature  16 G may have an effective watering area of approximately 50%. Other features  16 F,  16 H,  16 I,  16 J (illustrated in  FIG. 1A ) that do not require irrigation fluid  19  can influence the effective watering area upwards or downwards. In another example, an irrigation unit  20  that is positioned in the middle of the fairway  16 C may have an effective watering area of approximately 100%. 
   For example; because arranging the irrigation units  20  in substantially straight rows can be somewhat functionally arbitrary, the effective watering area of one or more irrigation units  20  can be somewhat reduced due to the presence of one or more features  16 A (illustrated in  FIG. 1A ),  16 B-D,  16 E (illustrated in  FIG. 1A ),  16 F-J within the irrigation region  30 . Thus, in the embodiment illustrated in  FIG. 1C , the irrigation units  20  are positioned so that the effective watering area of each irrigation region  30  is optimized. It is recognized that the irrigation lines  32  must likewise be positioned to provide irrigation fluid  19  to the irrigation units  20 , which may necessitate relocation of existing irrigation lines  32  in the event of a retrofit, or placement of new subterranean irrigation lines  32  for a new installation of the irrigation system  10 . 
     FIG. 1D  is a detailed top plan view of a representative irrigation region  30  from the golf hole  14 C illustrated in  FIG. 1C . In this example, the irrigation region  30  includes the irrigation unit  20 , vegetation  16 B, a fairway  16 C, rough  16 D, a sand trap  16 F, a cart path  16 H, and one or more alignment guides  38 . In one embodiment of the irrigation system  10 , the irrigation region  30  is divided into a plurality of irrigation subregions  34  (also referred to herein as “subregions”). The size, number and configuration of the irrigation subregions  34  can vary depending upon the irrigation requirements of the golf course  12 , the configuration of the irrigation region  30 , and the features  16 A-J included within the irrigation region  30 , as examples. 
   For convenience, in the embodiment illustrated in  FIG. 1D , the irrigation region  30  includes  100  substantially square irrigation subregions  34 , arranged in a ten by ten grid pattern  36 . In this embodiment, assuming an irrigation region having dimensions of 80 feet×80 feet, each irrigation subregion  34  would be 8 feet×8 feet. However, the grid pattern  36  can have any suitable dimensions. For example, the irrigation region  30  can be divided into a 20 by 20 grid pattern  36  so that the irrigation subregions  34  in this example would be 4 feet×4 feet. 
   In one embodiment, the subregions  34  of a given irrigation region  30  have approximately the same shape. In another embodiment, the subregions  34  of a give irrigation region  30  have approximately the same area. In still other embodiments, the subregions  34  can have differing shapes and/or areas within a given irrigation region  30 . In yet another embodiment, the irrigation region  30  and/or the subregions  34  within the irrigation region  30  can be irregular in shape. Moreover, the subregions  34  can be arranged so that they do not overlap, as illustrated in  FIG. 1D . 
   In the embodiment illustrated in  FIG. 1D , the irrigation subregions  34  are arranged on a standard X-Y coordinate scale. In this example, the irrigation subregion  34  in the lower left-hand corner is referred to herein as subregion (X 1 , Y 1 ), the irrigation subregion  34  in the lower right-hand corner is referred to herein as subregion (X 10 , Y 1 ), the irrigation subregion  34  in the upper left-hand corner is referred to herein as subregion (X 1 , Y 10 ), and the irrigation subregion  34  in the upper right-hand corner is referred to herein as subregion (X 10 , Y 10 ). Further, the irrigation unit  20  is centrally positioned at the corner of subregions (X 5 , Y 5 ), (X 5 , Y 6 ), (X 6 , Y 5 ) and (X 6 , Y 6 ). However, the positioning of the irrigation unit  20  within the irrigation region  30  need not be centrally located. In fact, depending upon the configuration of the irrigation region  30  and the features  16 A-J included within the irrigation region  30 , it may be advantageous to offset the positioning of the irrigation unit  20 . 
   The alignment guides  38  cooperate with the irrigation unit  20  to maintain proper positioning, calibration and/or orientation of the irrigation unit  20  within the irrigation region  30 , as described in greater detail below. With this design, the irrigation unit  20  can more accurately deliver irrigation fluid  19  to specific subregions  34  in a manner that reduces irrigation in unwanted areas. In the embodiment illustrated in  FIG. 1D , the irrigation region  30  includes three spaced apart alignment guides  38  that are radially positioned relative to the irrigation unit  20 , although the number and positioning of the alignment guides  38  can vary. For example, a single alignment guide  38  can be used in conjunction with each irrigation unit  20 . Alternatively, two alignment guides  38  or greater than three alignment guides  38  can be used. 
   One or more alignments guides  38  can be positioned within the irrigation region  30  as illustrated in  FIG. 1D , or can be positioned outside of the irrigation region  30 . Further, the alignment guides  38  can be fixedly positioned in the ground so that they are flush with or below the surface of the ground. In one embodiment, the alignment guide(s)  38  for one irrigation region  30  can be positioned on an irrigation unit  20  of another irrigation region  30 . Alternatively, the alignment guides  38  can be positioned so that they are above the surface of the ground. For example, one or more of the alignment guides  38  can be suspended above the ground on the trunk of a tree, or on any substantially immovable structure that is positioned on the golf hole  14 . Moreover, the alignment guides  38  can be at least a portion of any existing feature, manmade or natural, such as a rock, a tree, a wall, etc. Further, the shape and size of the alignment guides  38  can vary depending upon the design requirements of the irrigation system  10 , the irrigation unit  20  and the golf course  12 . 
   In one embodiment, the alignment guides  38  for a specific irrigation region  30  can each be positioned along the perimeter of the irrigation region  30 . Alternatively, the alignment guides  38  can be positioned within the perimeter of the irrigation region  30 . For example, in the embodiment illustrated in  FIG. 1D , the alignment guides  38  can be positioned at approximately 80% to 90% of the distance from the irrigation unit  20  toward the perimeter of the irrigation region  30 . Alternatively, the alignment guides  38  can be positioned any other distance from the irrigation unit  20 . Further, the three alignment guides  38  can be positioned at approximately 120 degree angles (or any other suitable angles) from each other relative to the irrigation unit  20  so that the alignment guides  38  form a triangle that surrounds the irrigation unit  20 . It is recognized that  FIG. 1D  represents only one of any number of possible configurations of the alignment guides  38  for one of the irrigation regions  30 , and that the number and position of alignment guides  38  can vary widely. For instance, the alignment guides  38  can form another type of polygon that either surrounds or does not surround the irrigation unit  20 . 
   In one embodiment, each alignment guide  38  is formed from a heat-absorbing and/or heat-emitting material. For instance, the alignment guide  38  can be formed from a material that emits a different amount of heat than the immediately surrounding area. In one embodiment, the alignment guide emits a greater amount of heat than the area that surrounds the alignment guide  38 . Alternately, the alignment guide  38  can be formed from a material that absorbs a different wavelength of light than the immediately surrounding area. The alignment guide  38  can be formed at least in part from plastics, epoxy resins, metals, composite materials, magnetic materials or any other suitable materials. 
     FIG. 1E  is another embodiment of a portion of a golf hole  14 E. In this embodiment, the irrigation units  20 E are each positioned within a corresponding irrigation region  30 E that is substantially hexagonal in shape. In the embodiment illustrated in  FIG. 1E , the hexagonally-shaped irrigation regions  30 E are arranged in a honeycomb pattern to increase the total area that is serviced by the irrigation units  20 E on the golf hole  14 E. However, it is recognized that the irrigation regions  30 E can be arranged in any suitable configuration. Moreover, the size of each irrigation region  30 E can vary depending upon the design of the irrigation units  20 E and the overall topography of the golf course  12 . Furthermore, the positioning of the irrigation unit  20 E within the irrigation region  30 E can vary, as illustrated in  FIG. 1E . For example, the irrigation unit  20 E can be centrally positioned within the irrigation region  30 E, or the irrigation unit  20 E can be off-center within the irrigation region  30 E. 
     FIG. 1F  is a detailed top plan view of a representative irrigation region  30 E from the golf hole  14 E illustrated in  FIG. 1E . In this example, the irrigation region  30 E includes the irrigation unit  20 E. In one embodiment of the irrigation system  10 , the irrigation region  30 E is divided into a plurality of substantially identical, triangular-shaped subregions  34 E. The size, number and configuration of the subregions  34 E can vary depending upon the irrigation requirements of the golf course  12 , the configuration and size of the irrigation regions  30 E, and the overall topography within the irrigation region  30 E, as examples. In the embodiment illustrated in  FIG. 1F , the irrigation region  30 E includes  216  subregions  34 E, although this number is illustrated as a representative example only. 
   In alternative embodiments, the hexagonal irrigation region  30 E can be divided into square or rectangular subregions  34  (illustrated in  FIG. 1D ), for example. In still another alternative embodiment, the irrigation region  30  can be circular, with the subregions  34  each having a wedge-shaped configuration. 
   The design of the irrigation unit  20  and the components of the irrigation unit  20  can be varied. One or more of the irrigation units  20  illustrated in  FIG. 1A  can have the features of the irrigation units  20  described herein. In one embodiment, the irrigation unit  20  can accurately and precisely irrigate each subregion  34  in the irrigation region  30  to the extent required. Additionally, the irrigation unit  20  can measure, monitor, and/or record (i) an irrigation fluid  19  temperature, (ii) an air temperature near the irrigation unit  20 , (iii) a surface temperature of the individual subregions  34 , (iv) the relative humidity near the irrigation unit  20 , (v) the wind speed near the irrigation unit  20 , (vi) the ambient light near the irrigation unit  20 , (vii) an irrigation start time for the irrigation unit  20 , (viii) an irrigation stop time for the irrigation unit  20 , (ix) an amount of irrigation fluid utilized by the irrigation unit  20 , and/or (x) a color of ground and/or ground covering at each individual subregion  34 . Further, the irrigation unit  20  can self-test the positioning of the irrigation unit  20  and/or self-test the components of the irrigation unit  20 . 
     FIG. 2A  is a perspective view of one embodiment of the irrigation unit  20 . In this embodiment, the irrigation unit  20  is retractable and includes a unit housing  200  having a first section  202 , a second section  204 , and a third section  206 . Alternatively, the unit housing  200  can include more than three or less than three sections. For example, the unit housing  200  can be a unit that does not retract. 
   In  FIG. 2A , the irrigation unit  20  is illustrated in the retracted position. In this position, the third section  206  is retracted into the second section  204 , and the second and third sections  204 ,  206  are retracted into the first section  202 . With this design, the irrigation unit  20  can be positioned in the ground so that in the retracted position, the entire irrigation unit  20  is at, near or below the surface of the ground. 
     FIG. 2B  is a perspective view of the irrigation unit  20  in the extended position with the second section  204  extended above the first section  202 , and the third section  206  extended above the second section  204 . In this embodiment, (i) the first section  202  includes a generally rectangular box-shaped first frame  208 , an opening  210  for receiving the second section  206  and a water inlet  212  that is in fluid communication with the fluid source  18 , (ii) the second section  204  includes a generally annular tube-shaped second frame  214 , and (iii) the third section  206  includes a generally annular tube-shaped side  216 , a generally disk-shaped top  218 , and a nozzle  220 . In this embodiment, the third section  206  is sized and shaped to fit into the second section  204 , and the second section  204  is sized and shaped to fit into the first section  202 . The height of the irrigation unit  20  in the extended position and the size of each section  202 ,  204 ,  206  can be designed to meet the requirements of the irrigation system  10  (illustrated in  FIG. 1A ). The first frame  208 , the second frame  214 , the side  216 , and the top  218  can be made of plastic or another type of durable material. 
   In one embodiment, the joints between one or more of the sections  202 ,  204 ,  206  are sealed to inhibit water, dirt, and/or other contaminants from entering into the components inside the sections  202 ,  204 ,  206 . Further, the top  218  can be substantially flat, or can have a convex shape to inhibit collection of irrigation fluid or rainwater, for example, on the top  218 . 
     FIG. 2C  is a top plan view of the irrigation unit  20 , including the first, second, and third sections  202 ,  204 ,  206 . 
     FIG. 2D  is a cut-away view of the first section  202  of the irrigation unit  20 . In this embodiment, the irrigation unit  20  includes a plurality of electronic components  221 . In one embodiment, the irrigation unit  20  includes (i) a power storage unit  222 , (ii) an electronic valve  224 , (iii) a flow sensor  226 , (iv) a first pressure sensor  228 A and/or a second pressure sensor  228 B, (v) a unit power source  230 , (vi) a fluid temperature sensor  232 , (vii) a flexible fluid conduit  234 , (viii) a section mover  236 , (ix) a section rotator  238 , and (x) a unit control system  240 . In this embodiment, these components are positioned in the first section  202 . Alternatively, one or more of these components can be positioned in another section  204 ,  206  or in another location. It should be noted that not all of these components are necessary. For example, the auxiliary power source  24  (illustrated in  FIG. 1A ) can be used instead of the unit power source  230 . Further, the orientation and/or positioning of these components can be changed. 
   In one embodiment, one or more of the sensors provided herein generates electronic data that relates to one or more parameters of the irrigation fluid  20 , and/or one or more parameters of the surrounding environment. 
   The power storage unit  222  stores electrical energy so that the electronic components of the irrigation unit  20  can function if the unit power source  230  is not providing power. In one embodiment, the power storage unit  222  directly transfers electrical energy to one or more of the electronic components of the irrigation unit  20 . In one embodiment, the power storage unit  222  only transfers electrical power to the irrigation unit  20 . 
   Non-exclusive examples of a suitable power storage unit  222  include one or more capacitors and/or batteries. The power storage unit  222  is in electrical communication with the unit control system  240  and some of the other components of the irrigation unit  20 . In one embodiment, the power storage unit  222  is recharged by the unit power source  230 . 
   In one embodiment, the power storage unit  222  is positioned within the housing  200  and is secured directly or indirectly to the housing  200 . In an alternative embodiment, the power storage unit  222  is positioned near and outside the housing  200 . In alternative, non-exclusive embodiments, for example, the power storage unit  222  can be within approximately 1, 5, 10, 50, 100 or 1000 yards of the housing  200 . 
   The electronic valve  224  is used to turn flow of the irrigation fluid  19  on and off, control the rate of the flow and/or pressure of the irrigation fluid  19  that is delivered to the nozzle  220  (illustrated in  FIG. 2B ) from the water inlet  212 . One example of an electronic valve  224  includes a valve  242 A, and a valve mover  242 B that precisely moves and positions the valve  242 A. The valve  242 A can be a gate valve, ball valve or another type of valve, and the valve mover  242 B can be a solenoid or another type of actuator. In this embodiment, the valve mover  242 B is electrically controlled by the unit control system  240  to selectively adjust the flow and/or pressure of the irrigation fluid  19  to the nozzle  220 . In the embodiment illustrated in  FIG. 2D , the electronic valve  224  is in fluid communication with the water input  212  and the flow sensor  226 . 
   As alternative examples, the electronic valve  224  can be selectively and alternatively controlled so that the flow of the irrigation fluid  19  from the water input  212  to the nozzle  220  can be completely on, completely off, or 10, 20, 30, 40, 50, 60, 70, 80, 90 or 95 percent of the flow from the water input  212  if the electronic valve  224  was not present. Stated another way, the electronic valve  224  can be selectively and alternatively controlled so that the valve  242 A is completely open, completely closed, or 10, 20, 30, 40, 50, 60, 70, 80, 90 or 95 percent open or any percentage open. 
   The flow sensor  226  measures the flow of the irrigation fluid  19  to the nozzle  220 . Suitable flow sensors  226  include a flow meter or turbine wheel with an electronic counter. The first pressure sensor  228 A measures the pressure of the irrigation fluid  19  that is being delivered to the irrigation unit  20  and the second pressure sensor  228 B measures the pressure of the irrigation fluid  19  that is being delivered to the nozzle  220 . Suitable pressure sensors  228 A,  228 B include a pressure gauge, electrical compression piles or a pressure changing transducer. 
   The unit power source  230  generates electrical energy, provides electrical energy to the electronic components  221  of the irrigation unit  20 , is in electrical communication with the electronic components  221  of the irrigation unit  20 , and/or charges the power storage unit  222 . Further, the unit power source  230  can directly transfer electrical energy to one or more of the electronic components  221  of the irrigation unit  20 . In one embodiment, the unit power source  230  only transfers electrical power to the electronic components  221  of the irrigation unit  20 . 
   In one embodiment, the unit power source  230  is a turbine type generator  244 A that includes a turbine  244 B that rotates a rotor  244 C relative to a stator  244 D to generate electrical energy. In one embodiment, the turbine  244 B is in fluid communication with at least a portion of the irrigation fluid  19  that is being delivered to the nozzle  220 . With this design, flow of the irrigation fluid  19  causes the turbine  244 B to rotate and power to be generated. In alternative embodiments, the turbine  244 B can include one or more fan blades, spline blades, or a squirrel cage fan that is rotated. 
   In one embodiment, the unit power source  230  can include an electronic voltage regulator (not shown) that regulates the voltage generated by the unit power source  230 . 
   Alternatively, the unit power source  230  can include another type of power generator. For example,  FIG. 2E  illustrates a top plan view of another embodiment of an irrigation unit  20 E that includes an alternative example of a unit power source  230 E. More specifically, in this embodiment, the unit power source  230 E is a solar type generator that includes a solar panel  244 E. In this embodiment, the solar panel  244 E is mounted on the top of the first section  202 . Alternatively, the solar panel  244 E can be mounted on another area of the irrigation unit  20 E or near the irrigation unit  20 E. 
   Alternatively, the unit power source  230  can include another type of generator, such as an electrolysis unit, a wind type generator, or a fuel cell. Still alternatively, the irrigation unit  20  can be designed without the unit power source  230  and the irrigation unit  20  can be electrically connected to the auxiliary power source  24  (illustrated in  FIG. 1A ) with one or more power lines. 
   In one embodiment, the unit power source  230  is positioned within the housing  200  and is secured directly or indirectly to the housing  200 . In an alternative embodiment, the unit power source  230  is positioned near and outside the housing  200 . In alternative, non-exclusive embodiments, for example, the unit power source  230  can be within approximately 1, 5, 10, 50, 100 or 1000 yards of the housing  200 . 
   In an alternative embodiment, power is transferred to one or more irrigation units  20  from the auxiliary power source  24  (illustrated in  FIG. 1A ). For example, one or more of the irrigation units  20  can be electrically connected to the auxiliary power source  24  with standard electrical lines. Alternatively, one or more of the irrigation units  20  can be electrically connected to the auxiliary power source  24  via the irrigation lines  32 . In this embodiment, power is transferred from the auxiliary power source  24  through the irrigation fluid  19  in the irrigation lines  32 . 
   Referring back to  FIG. 2D , the fluid temperature sensor  232  measures the temperature of the irrigation fluid  19  that is delivered to the nozzle  220 . Suitable fluid temperature sensors  232  include a thermistor or other electronic devices that change resistance or capacitance with changes of temperature. 
   The flexible fluid conduit  234  connects the water input  212  in fluid communication with the nozzle  220  and allows the nozzle  220  to be moved up and down and rotated. Suitable fluid conduits  234  include a rubber tube or another type of flexible conduit. 
   The section mover  236  moves the second section  204  (illustrated in  FIG. 2B ) and/or the third section  206  up and down vertically along a unit longitudinal axis  246  (along the Z axis) relative to the first section  202  between the retracted position and the extended position. The section mover  236  can include one or more movers, such as rotary motors, voice coil motors, linear motors utilizing a Lorentz-type force to generate drive force, electromagnetic movers, planar motors, or some other force movers. In another embodiment, the second section  204  and/or the third section  206  can move up and down using irrigation fluid pressure. 
   The section rotator  238  rotates the third section  206  and/or the nozzle  220  about the unit longitudinal axis  246  (about the Z axis) relative to the first section  202 . The section rotator  238  can include one or more movers, such as rotary motors, voice coil motors, linear motors utilizing a Lorentz force to generate drive force, electromagnetic movers, planar motors, or some other force movers. 
   The unit control system  240  is in electrical communication with many of the components of the irrigation unit  20  and controls many of the components of the irrigation unit  20 . In one embodiment, the unit control system  240  includes a printed circuit board  240 A, an electronic processor  240 B, and/or a data storage device  240 C. The electronic processor  240 B processes electronic data and can include one or more conventional CPU&#39;s. In one embodiment, the electronic processor  240 B is capable of high volume processing and database searches. The data storage device  240 C stores electronic data and algorithms for controlling operation of the irrigation unit  20  as described below. The data storage device  240 C can include one or more magnetic disk drives, optical storage units, random access memory (RAM), read only memory (ROM), electronically alterable read only memory (EAROM), and/or flash memory, as non-exclusive examples. 
   In one embodiment, the unit control system  240  can receive and store information from (i) the flow sensor  226  regarding flow of the irrigation fluid, (ii) the fluid temperature sensor  232  regarding the temperature of the irrigation fluid  19 , and (iii) the pressure sensors  228 A,  228 B regarding the pressure of the irrigation fluid  19 . Additionally, the unit control system  240  can receive and store information from other components of the irrigation unit  20  as described below. Alternately, for example, one or more of these components can provide the information directly to the main control system  22  (illustrated in  FIG. 1A ). 
   Moreover, for example, the unit control system  240  can control (i) the electronic valve  224  to precisely control the flow rate and/or pressure of the irrigation fluid  19  to the nozzle  220 , (ii) the section mover  236  to precisely control the position of the second and/or third sections  204 ,  206 , along the Z axis and the position of the nozzle  220  along the Z axis, and/or (iii) the section rotator  238  to precisely control the rotational position of the second and third sections  204 ,  206 , about the Z axis and the rotational position of the nozzle  220  about the Z axis, the X axis and/or the Y axis. With this design, the nozzle  220  can effectively oscillate back and forth, and up and down relative to the irrigation region  30 . Additionally, the unit control system  240  can control other components of the irrigation unit  20  as described below. Alternately, for example, one or more of these components can be controlled directly or indirectly by the main control system  22 . 
   In one embodiment, the unit control system  240  is in electrical communication with the main control system  22 . For example, the unit control system  240  can communicate with the main control system  22  and transfer data from the irrigation unit  20  to the main control system  22  on a periodic basis or continuous basis. For example, the unit control system  240  can communicate with the main control system  22  and can (i) upload data to the main control system  22 , (ii) download data from the main control system  22 , (iii) download new programming from the main control system  22 , (iv) download new firmware from the main control system  22 , and/or (v) download new software from the main control system  22 , (vi) detect missing or disabled irrigation units  20 , and can selectively enable and/or disable one or more irrigation units  20 . Additionally, the unit control system  240  can communicate with the main control system  22  if there are problems with the irrigation unit  20  and/or any of the ground coverings in any of the subregions  34 . Moreover, delays or breaks in communication between the unit control system  240  and the main control system  22  can signal problems with the irrigation system  10 . 
     FIG. 2F  is a front plan view of the third section  206  of the irrigation unit  20 . In this embodiment, the third section  206  includes (i) a nozzle opening  248 , (ii) the nozzle  220 , (iii) a first wind speed sensor  250 A and/or a second wind speed sensor  250 B, (iv) a first light sensor  252 A and/or a second light sensor  252 B, (v) a first humidity sensor  254 A and/or a second humidity sensor  254 B, (vi) a first air temperature sensor  256 A and/or a second air temperature sensor  256 B, (vii) a subregion sensor opening  258 , (viii) a subregion sensor  260 , and (ix) an electrical interface  261 . In this embodiment, one or more of these components are positioned in or on the third section  206 . Alternatively, one or more of these components can be positioned in or on another section  202 ,  204  or in another location. Further, one or more of these components can be positioned flush with the top  218 . It should be noted that not all of these components may be necessary for the operation of the irrigation unit  20 . 
   The nozzle opening  248  extends through the side  216  of the third section  206 , allows the nozzle  220  to be positioned inside the third section  206  and direct the irrigation fluid  19  outside the third section  206 , and allows the nozzle  220  to be moved relative to the side  216 . The size and shape of the nozzle opening  248  can be varied to suit the movement requirements of the nozzle  220 . In  FIG. 2F , the nozzle opening  248  is generally rectangular shaped. 
   The nozzle  220  releases and directs the irrigation fluid  19  to the various subregions  34 . In one embodiment, the nozzle  220  is generally tubular shaped and includes a nozzle opening  262  that directs a stream of the irrigation fluid at the respective subregion to reduce the amount of evaporation when the air is hot and/or dry. In one embodiment, to obtain an accurate and even distribution of the irrigation fluid  19  to the various subregions  34 , the nozzle  220  is oscillated both up and down and sideways, right and left. This allows the stream to evenly cover and distribute the irrigation fluid  19 . Alternatively, for example, the nozzle  220  could be designed to have a pulsed stream, a spray or a pulsed spray. Still alternatively, for example, the valve mover  242 B can move the valve  242 A to achieve a pulsed spray or other spray pattern. 
   In one embodiment, in the extended position, the nozzle  220  is approximately 12 inches above the ground. Alternatively, for example, the nozzle  220  can be more than or less than 12 inches above the ground. 
   The wind speed sensors  250 A,  250 B measure the wind speed near the irrigation unit  20 . In one embodiment, the first wind speed sensor  250 A measures wind speed when the irrigation unit  20  is in the extended position and the second wind speed sensor  250 B measures wind speed when the irrigation unit  20  is in the retracted position. Suitable wind speed sensors  250 A,  250 B include a thermistor with a heater. Measuring how fast the thermistor changes resistance can be correlated to wind speed. 
   The light sensors  252 A,  252 B measure the light near the irrigation unit  20 . In one embodiment, the first light sensor  252 A measures the light when the irrigation unit  20  is in the extended position and the second light sensor  252 B measures the light when the irrigation unit  20  is in the retracted position. Suitable light sensors  252 A,  252 B include various photo cells and light sensitive electronics sensitive to visible light. 
   The humidity sensors  254 A,  254 B measure the humidity near the irrigation unit  20 . In one embodiment, the first humidity sensor  254 A measures the humidity when the irrigation unit  20  is in the extended position and the second humidity sensor  254 B measures humidity when the irrigation unit  20  is in the retracted position. Suitable humidity sensors  254 A,  254 B include a hygrometer and other moisture sensitive electronic devices sensitive to moisture. 
   The air temperature sensors  256 A,  256 B measure the air temperature near the irrigation unit  20 . In one embodiment, the first air temperature sensor  256 A measures the air temperature when the irrigation unit  20  is in the extended position and the second air temperature sensor  256 A measures the air temperature when the irrigation unit  20  is in the retracted position. Suitable air temperature sensors  256 A,  256 B include a thermistor or other temperature sensitive electronic devices. 
   The subregion sensor opening  258  extends through the side  216  of the third section  206 , allows the subregion sensor  260  to be positioned inside the third section  206  and monitor the subregions  34  outside the third section  206 , and allows the subregion sensor  260  to be moved relative to the side  216 . The size and shape of the subregion sensor opening  258  can be varied to suit the movement requirements of the subregion sensor  260 . In  FIG. 2F , the subregion sensor opening  258  is generally rectangular shaped. 
   The subregion sensor  260  monitors the status of one or more of the subregions  34  in the irrigation region  30 . In one embodiment, the subregion sensor  260  directly or indirectly measures the temperature at a portion of each subregion  34 . In another embodiment, the subregion sensor  260  can be used to directly or indirectly measure the moisture content of a portion of one or more subregions  34 . For example, in this embodiment, the subregion sensor  260  can be used in conjunction with one or more other sensors to measure the temperature of a portion of a subregion  34 , the humidity and/or the air temperature. This information can then be used in an algorithm to indirectly determine the moisture content of the portion of the subregion  34 . Additionally, or alternatively, the subregion sensor  260  can measure or detect the color or other features of the surface covering of each subregion  34 . For example, the subregion sensor  260  can determine which subregions  34  have the desired color, e.g. green, and which subregions  24  are turning an undesired color, e.g. brown. 
   In one embodiment, the subregion sensor  260  can include an infrared sensor  260 A that receives an infrared signal. In this embodiment, the infrared sensor  260 A can be sequentially directed at each individual irrigation subregion  34  to independently receive an infrared signal at each individual irrigation subregion  34  to individually measure the subregion temperature at each subregion  34 . Additionally, in one embodiment, the subregion sensor  260  can include a lens  260 B that intensifies the light collected by the subregion sensor  260 . For example, the lens  260 B can be a lenticular or Fresnel type lens that is designed to optimize the IR signal and concentrate it on the IR sensor  260 A. 
   Additionally or alternatively, for example, the subregion sensor  260  can include a visible light detector  260 C that is sequentially directed at each individual irrigation subregion  34 . In this embodiment, the lens  260 B can be designed and optimized for the low incidence angle for the visible and infrared wavelengths. In still alternative embodiments, the subregion sensor  260  can include an optical sensor or a pattern recognition sensor, as non-exclusive examples. 
   In one embodiment, in the extended position, the subregion sensor  260  is approximately 24 inches above the ground. Alternatively, for example, the subregion sensor  260  can be more than or less than 24 inches above the ground. 
   In one embodiment, the lenses and sensors can be coated with a high density non-stick coating  259 C (illustrated as shading) such as polytetraflouroethylene to inhibit adhesion of material, such as dirt, chemicals, water minerals, impurities, and deposits to the lenses and sensors. 
   Additionally, referring back to  FIG. 2B , the irrigation unit  20  can include a cleaner unit  259 U that can be used to clean one or more of the lenses and/or sensors. For example, the cleaner unit  259 U can include (i) a nozzle to direct irrigation fluid, water or a cleaning fluid on one or more of the lenses and/or sensors and/or (ii) a material such as cloth or chamois that can wipe one or more of the lenses and/or sensors. 
   The electrical interface  261  allows for an external control system  326  (illustrated in  FIG. 3 ) to interface with the unit control system  240 . In one embodiment, the electrical interface  261  is an input jack that is electrically connected to the unit control system  240 . In this embodiment, the external control system  326  includes an electrical connector that inputs into the input jack. In another embodiment, for example, the electrical interface  261  can be an electrical receiver/transmitter that interfaces with a receiver/transmitter of the external control system  326  to allow for data transfer within the irrigation system  10  between the systems  326 .  240 . With these designs, the external control system  326  is either wirelessly, visible light, or invisible light, inductively, or capacitively coupled to the unit control system  240 . 
   It should be noted, for example, in an alternative embodiment, that the electrical interface  261  can be mounted on the top edge of the section  202 . 
   The unit control system  240  (illustrated in  FIG. 2C ) is in electrical communication with and receives information from the wind speed sensors  250 A,  250 B, the light sensors  252 A,  252 B, the humidity sensors  254 A,  254 B, the air temperature sensors  256 A,  256 B, and the subregion sensor  260 . Stated another way, the unit control system  240  monitors and stores on a programmable periodic basis, air temperature, humidity, wind speed and visible light with times. Alternately, for example, one or more of these components can provide the information directly or indirectly to the main control system  22  (illustrated in  FIG. 1A ). 
   Based on the data gathered by the unit control system  240 , the unit control system  240  can determine which subregions  34  need irrigation, the best time to irrigate, and the appropriate quantity to irrigate. 
   Additionally, with this information problems with the irrigation unit  20  and/or the ground covering in each subregion  34  can be detected and reported to the main control system  22 . 
   In one embodiment, based on the information received by the unit control system  240 , the unit control system  240  using algorithms based on the previous data, e.g. recorded air temperature, humidity, wind speed and/or visible light, can determine how much irrigating, if any, needs to be done. 
     FIG. 2G  is a cut-away view of one embodiment of the third section  206  of the irrigation unit  20 .  FIG. 2G  illustrates that the irrigation unit  20  includes (i) a nozzle pivot  264  that secures the nozzle  220  to the side  216  of the third section  206  and allows the nozzle  220  to pivot relative to the third section  206 , (ii) a sensor pivot  266  that secures the subregion sensor  260  to the side  216  of the third section  206  and allows the subregion sensor  260  to pivot relative to the third section  206 , and (iii) a nozzle mover  268  that moves and pivots the nozzle  220  and the subregion sensor  260  relative to the third section  206 . The nozzle mover  268  can include one or more movers, such as rotary motors, voice coil motors, actuators, linear motors utilizing a Lorentz-type force to generate drive force, electromagnetic movers, planar motors, or some other force movers. In  FIG. 2F , the nozzle mover  268  is coupled with a nozzle linkage  270  to the nozzle  220  and a sensor linkage  272  to the subregion sensor  260 . With this design, the nozzle mover  268  concurrently moves both the nozzle  220  and the subregion sensor  260 . Alternatively, for example, separate movers (not shown) can be used to individually move the nozzle  220  and the subregion sensor  260 . Still alternatively, the nozzle  220  and the subregion sensor  260  can be fixedly attached together and can move together. 
   The unit control system  240  can control the nozzle mover  268  to precisely control the position of the nozzle  220  and the subregion sensor  260 . With this design, by controlling the section mover  236  (illustrated in  FIG. 2D ), the section rotator  238  (illustrated in  FIG. 2D ), and the nozzle mover  268 , the unit control system  240  can individually and selectively direct the subregion sensor  260  at each subregion  34  and receive information from each subregion  34 . Further, with this design, by controlling the section mover  236 , the section rotator  238  (illustrated in  FIG. 2D ), and the nozzle mover  268 , and the electronic valve  224  (illustrated in  FIG. 2D ), the unit control system  240  can individually and selectively direct the irrigation fluid  19  from the nozzle  220  at any one or every one of the subregions  34 . Alternatively, for example, one or more of these components can be controlled directly or indirectly by the main control system  22 . 
   As used herein, the section mover  236 , the section rotator  238  and the nozzle mover  268  are individually and/or collectively referred to as a nozzle mover assembly. As provided herein, the nozzle mover assembly can include additional movers to position and move the nozzle  220  and/or the subregion sensor  260 . 
   In the embodiment illustrated in  FIG. 2G , the irrigation unit also includes a nozzle sensor  276  and a rotation sensor  278 . The nozzle sensor  276  can detect the relative positioning of the nozzle  220  about one or more axes. In other words, the nozzle sensor  276  can sense the angle of the nozzle  220  about any axis, and can transmit this information to the unit control system  240 . The unit control system  240  can use this information to determine whether the nozzle  220  is properly angularly positioned to irrigate the desired subregion  34 . In an alternative embodiment, the position of the nozzle  220  can be determined by monitoring the amount of current (or other power) that has been directed to the nozzle mover assembly, e.g. to move the nozzle  220  from a predetermined starting position. 
   The positioning of the nozzle sensor  276  can be varied depending upon the design requirements of the irrigation unit  20 . In this embodiment, the nozzle sensor  276  is positioned in the interior of the third section  206 . In an alternative embodiment, the nozzle sensor can be positioned on the nozzle, or in another suitable location. 
   The rotation sensor  278  can detect the rotation of the third section  206 , and thus the nozzle  220 , relative to the second section  204 , the first section  202 , the sprinkler housing  200  and/or the irrigation region  30 . In other words, the rotation sensor  278  can monitor the 360 degree rotational positioning of the third section  206  to determine whether the third section  206  is properly oriented to deliver irrigation fluid  19  to the desired subregion  34 . The rotation sensor  278  transmits this information to the unit control system  240 . The unit control system  240  can use this information to determine whether the nozzle  220  is accurately rotationally positioned to irrigate the desired subregion  34 . In an alternative embodiment, the position of the third section  206 , and thus the rotational position of the nozzle  220 , can be determined by monitoring the amount of current (or other power) that has been directed to the section rotator  238 , e.g. to move the third section  206  from a predetermined starting position. 
   The positioning of the rotation sensor  278  can be varied depending upon the design requirements of the irrigation unit  20 . In this embodiment, the rotation sensor  278  is positioned on the exterior of the third section  206 . In an alternative embodiment, the rotation sensor  278  can be positioned in the interior of the third section  206 , on the exterior or in the interior of the second section  204 , or in another suitable location. 
   With this design, the unit control system  240  accurately (i) controls the movement of the nozzle  220  head up, down or around, (ii) controls the pressure and flow of the irrigation fluid  19  to the nozzle  220 , and/or (iii) turns the irrigation fluid  19  on and off, including when the nozzle  220  is directed at sand traps  16 F, cart paths  16 H, water features  16 G, walkways  16 J, or other areas where irrigation fluid  19  is not necessarily desired. In this manner, the irrigation unit  20  is able to accurately and individually irrigate each subregion  34  of each irrigation region  30  to the desired level, and in the required order. This can result in virtually no overlap between adjacent irrigation units  20 , and therefore, little or no wasted irrigation fluid  19 , thereby saving costs for both irrigation fluid  19  and electricity to pump the irrigation fluid  19 . 
     FIG. 2H  is a cut-away view of the third section  206  of the irrigation unit  20 .  FIG. 2H  illustrates that in one embodiment, the subregion sensor  260  is offset from the nozzle  220 . The amount of offset can vary. For example, the subregion sensor  260  can be offset approximately 90 degrees of the nozzle  220 . Alternatively, the offset can be greater or less than 0 degrees. 
   In  FIG. 2H , the nozzle  220  pivots near the end of the nozzle  220 . Alternatively, for example, the nozzle  220  can pivot at the center of the nozzle  220  or about another area. 
     FIG. 2I  is a perspective view of another embodiment of the irrigation unit  20 I. In this embodiment, the irrigation unit  20 I includes a protective cover  274  that distributes the load and protects the irrigation unit  20 I. In  FIG. 2I , the protective cover  274  is a flat or slightly convex plate that is secured to the top of the third section  206 . The composition of the protective cover  274  can vary, provided the protective cover is sufficiently rigid to withstand forces from pedestrians, golf carts and other vehicles, golf bags, pull carts, tractors, lawnmowers, other landscaping equipment or any other forces that could possibly damage the irrigation units  20 I. 
     FIG. 2J  is a perspective view of still another embodiment of the irrigation unit  20 J. In this embodiment, the protective cover  274 J is slightly curved or convex shaped so that water and other debris fall more easily off the cover  274 J. With this design, the sensors  250 B,  252 B,  254 B,  256 B are less likely to be covered. Still alternatively, the protective cover can have another shape such as slightly pitched, slightly concave, arched, or slightly inclined. 
   Referring back to  FIG. 1D , in one embodiment, at one or more times, e.g. at programmable time intervals, the irrigation unit  20  also verifies the relative positioning of the irrigation unit  20  and adjusts and/or corrects the position of the nozzle  220  (illustrated in  FIG. 2B ) as needed. If the position cannot be corrected by the irrigation unit  20 , a signal can be sent to the main control system  22  so that the irrigation unit  20  is manually repositioned or otherwise recalibrated or fixed. Thus, if the irrigation unit  20  is damaged or moved, it can correct the problem or notify the main control system  22  via the unit control system  240 . 
   In one embodiment, the subregion sensor  260  is utilized to determine if the nozzle  220  is directing the irrigation fluid  19  to the appropriate desired area. For example, the alignment guides  38  (illustrated in  FIG. 1D ) for a particular irrigation region  30  are monitored with the subregion sensor  260  prior to or during irrigation to determine if the nozzle  220  is being correctly positioned to irrigate these positions. In  FIG. 1D , the alignment guides  38  are located approximately 120 degrees apart at about 80% to 90% of the distance of the irrigation distribution throw. The subregion sensor  260  can locate and monitor these positions to make certain that the positioning of the nozzle  220  is true and accurate. In one embodiment, the unit control system  240  is programmed to know where these alignment guides  38  are located within the irrigation region  30 . 
   On a periodic or continual basis, the subregion sensor  260  can locate one or more of the alignment guides  38  for the specific irrigation region  30  based on information that can be initially programmed into the unit control system  240 . Stated another way, the unit control system  240  can cause the subregion sensor  260  to be positioned to detect heat or a specific wavelength of light from the alignment guides  38  in a specific direction based on an initial positioning of the alignment guides  38  relative to a portion of the irrigation unit  20 , such as the subregion sensor  260 , for example. In another embodiment, the subregion sensor  260  can detect a particular physical pattern or signature that is imprinted or impregnated on the alignment guide  38 . 
   If, however, the irrigation unit  20  moves from its initial orientation, i.e. from impact with a golf cart, vandalism, or any other unwanted movement, and the subregion sensor  260  is unable to detect one of the alignment guides  38  at its initial position, the unit control system  240  can cause one or more of the actuators to oscillate the subregion sensor  260  up and down, side to side, or both, until the alignment guide  38  is located by the subregion sensor  260 . Once one or more of the alignment guides  38  are located in this manner by the subregion sensor  260 , information regarding the extent of the necessary oscillation until such alignment guide(s)  38  were located, i.e. angle, direction and/or distance, is provided by the subregion sensor  260  to the unit control system  240  for processing. The unit control system  240  can then determine the extent to which the irrigation unit  20  has been moved, dislodged, disoriented or the like, from its initial orientation, along or about any axis. 
   Once this extent is determined, the unit control system  240  can adjust the flow rate of irrigation fluid  19  to the nozzle  220  and/or the positioning of the nozzle  220  accordingly, i.e. about or along any axis, so that the coordinates for each subregion  34  in the irrigation region  30  are effectively recalibrated and accurate irrigation is maintained. Stated another way, with the extent of misalignment determined, the unit control system  240  can compensate for the misalignment. The irrigation unit  20  can then be automatically or manually reprogrammed to effectively recalibrate the irrigation unit  20  based on its modified orientation relative to the alignment guides  38 . With this design, any disruption or offset of irrigation of the irrigation region  30  can be reduced or eliminated despite unwanted movement of the irrigation unit  20  along or about any axis. 
   The way in which the position of the irrigation unit  20  relative to the alignment guides  38  is determined can vary. For example, the subregion sensor  260  can detect the heat, light or color to locate one or more alignment guides  38 . Alternatively, for example, the subregion sensor  260  can send a signal that is reflected off of the alignment guides  38  to locate one or more alignment guides  38 . Still alternatively, for example, one or more of the alignment guides  38  can send a signal that is received by the subregion sensor  260  to locate the alignment guides  38 , or one or more of the alignment guides can include a sensor that determines the position of the irrigation unit  20 . 
     FIG. 3  illustrates that the irrigation units  20  can be electrically connected and/or coupled to the main control system  22 . It should be noted that one or more of the functions performed by the main control system  22  and described herein can be performed by one or more of the unit control systems  240  (illustrated in  FIG. 2D ). Further, one or more of the functions performed by the unit control systems  240  and described herein can be performed by the main control system  22 . 
   The main control system  22  can include a personal computer (PC), or workstation, and can include (i) a central processing unit (CPU)  310 , (ii) one or more forms of memory  312 ,  314  such as EPROM, EAROM, magnetic or optical storage drives, (iii) one or more peripheral units such as a keyboard  316  and a display  318 , (iv) a data encoder/decoder unit  320  which provides two-way communication between the irrigation units  20  and the main control system  22 , and/or (v) an internal bus  301  that electrically connects one or more of the components of the main control system  22 . The data encoder/decoder unit  320  encodes data on the internal bus  301  under control of the CPU  310 . The encoded data is then transmitted over the data line  28  to the irrigation unit(s)  20 . Incoming data from the irrigation units  20  is decoded by the data encoder/decoder unit  320  and used by the CPU  310  and stored in one or more of the memory units  312 ,  314 . 
   Alternatively, for example, the main control system  22  can communicate with the irrigation units  20  wirelessly using the irrigation fluid  19  flowing through the irrigation lines  32 . In this case, for example, the encoded signals are transmitted by electromagnetic waves, DC/AC signal, visible or invisible light, or RF signals through the irrigation fluid  19  in the irrigation lines  32 . The encoded signal is sent from an antenna, or aerial  322 , located in the irrigation line  32 , and electrically connected to the encoder/decoder  320  in proximity to the main control system  22 , and this signal is transmitted through the irrigation fluid  19  flowing in the irrigation line  32 . The signal is then received at the irrigation unit(s)  20  by another antenna  324  electrically connected to the unit control system  240  and located in the irrigation line  32  in proximity to the irrigation unit(s)  20 . Additional connections (not shown) can be located in irrigation lines  32  and the ground proximate the main control system  22  and each irrigation unit  20 , for transmitting and receiving the encoded signals via the earth and in combination with transmission via the irrigation fluid  19 . 
   In the case of transmission of the encoded signals using electromagnetic waves or DC/AC signal, a ground to earth at the irrigation unit  20  and at the main control system  22  can be used. At the irrigation unit  20 , the ground to earth can consist of a ground spike  328  (only one ground spike  328  is illustrated in  FIG. 3 ) that is implanted into the earth near the irrigation unit  20 , with a wire  330  connecting the ground spike to the irrigation unit  20 . In another embodiment, the irrigation unit  20  can have bare metal wires (not shown) that extend into the earth, or the irrigation unit  20  can include a metallic bottom (not shown) that directly contacts the earth. 
   In alternative embodiments, the communication between the main control system  22  and the irrigation units  20  can be accomplished using RF signals through the air, infrared and/or other non-visible light signals, or using fiber optic cables, as non-exclusive examples. Furthermore, each irrigation unit  20  can retransmit a received signal to other irrigation units  20  in the irrigation system  10  to keep the signal strength high in the network. In one embodiment, while different irrigation units  20  receive and retransmit the signal, each irrigation unit  20  can have a unique identifier or serial number (ID). In this design, only the irrigation unit  20  having a predetermined ID will respond to the signal. 
   The main control system  22  monitors and controls the overall operation of the irrigation system  10  based on firmware algorithms stored in magnetic or optical disks, the Read Only Memory unit (ROM)  312 , and/or stored in the unit control systems  240 . Data and programming information stored at each unit control system  240  can also be stored in the main control system  22 . The main control system  22  can troubleshoot problems in the irrigation system  10  and take faulty or otherwise problematic irrigation units  20  off the system until they can be repaired or replaced. 
   In one embodiment, the main control system  22  is additionally used to program or reprogram the irrigation units  20  with upgraded firmware, new irrigation sequences, and/or new irrigation requirements for changes in vegetation or reconfigured irrigation regions  30 , as non-exclusive examples. Additionally, in one embodiment, the main control system  22  can control the sequence of the start times for each irrigation unit  20 . Furthermore, the main control system  22  can be used to override the set irrigation duration, times, and control the irrigation units  20  to irrigate at other times. 
   In monitoring the operation of the irrigation system  10 , the main control system  22  can obtain and store all data collected at and associated with each irrigation unit  20 . The main control system  22  compares current and previously received data to provide statistical data and determine whether the irrigation system  10  and/or one or more of the irrigation units  20  are operating properly. For example, the main control system  22  collects data including the quantity of irrigation fluid used for each irrigation unit  20  over time, and the main control system  22  can compare the current usage for a given irrigation unit  20  to past usage amounts. If there is a significant change in usage amounts (e.g. above a threshold percentage) during a particular period in time, this could indicate that a problem exists at that irrigation unit  20  or in the irrigation line  32  leading toward or away from that irrigation unit  20 . 
   For example, the main control system  22  can compare the irrigation fluid  19  usage for an irrigation unit  20  against the total system usage amount to determine if there is a potential problem in the irrigation line  32  (e.g. otherwise undetectable breaches in the irrigation line  32 ) and/or the irrigation unit  20 . In other words, the main control system  22  can cooperate with the irrigation units  20  to determine if there are any “invisible” underground irrigation line breaks by comparing total irrigation unit  20  usage with the total irrigation fluid  19  initially delivered to one or more of the irrigation units  20 . 
   For example, the irrigation system  10  can perform a static pressure test during non-irrigation times by obtaining a measurement of the irrigation fluid pressure near a fluid meter  330  positioned near a pump station (not shown) or fluid source  18  (illustrated in  FIG. 1A ), and comparing this measured pressure with the irrigation fluid pressure at the first pressure sensor  228 A of one or more of the irrigation units  20 . A disparity in pressure above a predetermined threshold percentage from near the fluid meter  330  to the irrigation unit  20  can indicate to the main control system  22  that a problem with a nearby irrigation line  32  exists, or it can be indicative of a problem with the irrigation unit  20  from which the decreased pressure was measured. This type of testing is enabled because of the ability of the irrigation system  10  to pressurize the irrigation lines without actually sending irrigation fluid  19  through the irrigation units  20 . 
   Further, the irrigation system  10  can perform a dynamic pressure test by comparing the expected irrigation fluid pressure at one or more irrigation units  20  (taking into account elevation differences between the water source  18  and/or pump station  330  and the irrigation units  20 ) during an irrigation cycle, and comparing this expected pressure with the actual measured irrigation fluid pressure from the first pressure sensor  228 A or the second pressure sensor  228 B at the one or more irrigation units  20  during an irrigation cycle. If the expected pressure is a predetermined percentage above the measured pressure, this can be indicative of a breach in the irrigation line  32 . By selectively activating certain irrigation units  20 , the approximate location of the breached irrigation line can be determined. Any detected potential problem can be indicated on the display  318  of the main control system  22 . With this design, a substantial amount of irrigation fluid can be saved as a result of detecting a leak when such leak could otherwise go undetected for an extended period of time. 
   Additionally, the main control system  22  can (i) collect all programming information for each irrigation unit  20 , (ii) display all vegetation problems or failures reported by the irrigation units  20 , (iii) poll all the irrigation units  20  to make certain they are there and functioning properly, (iv) reprogram any existing or replacement irrigation units  20  with the stored head programming data from the irrigation units  20 , (v) reprogram any or all of the irrigation units  20  with new firmware, and/or (vi) reprogram the location(s) of the subregion(s)  34  in one or more irrigation regions  30 , change from routine irrigating to new from seed irrigating, etc. 
   In another embodiment, the main control system  22  can control the sequence of start times for the individual irrigation units  20 . Moreover, the manufacturer can be able to poll the main control system  22  and download all data with a modem. The data can be used by the manufacturer to enhance the algorithms and add new features. 
   Further, the main control system  22  can be utilized to determine if the irrigation units  20  are all operational, because the main control system  22  is in periodic and/or continuous communication with the irrigation units  20 . For example, each irrigation unit  20  can be programmed to perform a self-test prior to irrigating its respective irrigation region  30 . If there is a problem with the self-test, the unit control system  240  can communicate a fault to the main control system  22 . 
   In one embodiment, the self-test can include determining whether the irrigation unit  20  is properly oriented relative to the alignment guides  38 . Other self-testing functions can include taking humidity and/or temperature readings to determine proper functioning of one or more of the sensors, and checking proper functioning of the data storage device (RAM unit, ROM unit, EAROM), the power storage unit (battery or capacitor storage), the unit power source, communications, irrigation fluid pressure, etc. In one embodiment, the data from each irrigation unit  20  is compared with surrounding irrigation units  20  to determine whether a specific irrigation unit  20  is functioning consistently with other nearby irrigation units  20 . For instance, in the event that one irrigation unit  20  is generating data indicating a greater than 5% disparity from one or more surrounding irrigation units  20 , then main control system  22  can determine that a problem with the irrigation unit  20  may exist. This threshold percentage can vary depending upon the desired sensitivity of the system or the type of data being analyzed, and can be greater or less than 5%, i.e. 1%, 2%, 10%, 20%, 30%, 50%, 75%, 100%, or some other appropriate percentage. 
   The main control system  22  can attempt a repair of the irrigation unit  20  by sending a reset command to the unit control system  240 , or by reprogramming the unit control system  240 , after which the irrigation unit  20  can perform the self-test again. If no potential problem is indicated, then the irrigation unit  20  can proceed with the newly programmed irrigation plan. Alternatively, if there still is a potential problem, the main control system  22  can turn off the irrigation unit  20  and flag it for repair. In one embodiment, if an irrigation unit  20  needs to be replaced, the replacement irrigation unit  20  can be installed and programmed very efficiently since the information for each irrigation unit  20  is stored in the main control system  22 . 
   Turning back to the control of the irrigation units  20 , the irrigation unit  20  is controlled by one or more algorithms that are stored in and use information associated with each irrigation unit  20 . The algorithms and initial information can be programmed into the unit control system  240  of the irrigation units  20  or can be downloaded from the main control system  22  or downloaded through the electrical interface  261 . Initial information for each irrigation unit  20  can include (i) specific identification indicia, such as a serial number or ID, for the irrigation unit  20 , (ii) topographical information, such as the slope and elevation of the region  30  and each subregion  34  within the irrigation region  30  for that irrigation unit  20 , (iii) the type of grass or vegetation within each irrigation region  30  and subregion  34 , and/or (iv) information defining the configuration or shape of the irrigation region  30  to be irrigated by the respective irrigation unit  20 . 
   The algorithms can be utilized to control the irrigation sequences for each respective irrigation unit  20 . After the irrigation sequences are determined for each irrigation unit  20 , a priority for when the irrigation unit  20  is to perform its irrigation sequence is established and assigned to each irrigation unit  20 . 
   In one embodiment, the algorithms and initial information for each irrigation unit  20  is programmed into the unit control system  240  for each irrigation unit  20  by an operator. In one embodiment, the initial information is inputted using a portable computing device  326  that is directly, wirelessly, inductively or capacitively coupled, or coupled using visible or invisible light, to the electronics of the unit control system  240  for one or more of the irrigation units  20  and/or the main control system  22 . For example, the portable computing device  326  can be in communication with the electrical interface  261  of one or more of the irrigation units  20 . In one embodiment, the portable computing device  326  is wirelessly connected to the irrigation unit  20  and/or the main control system  22  during programming of the irrigation units  20 . With this connection, all of the irrigation units  20  in the system  10  can be programmed. Alternatively, in another embodiment, the algorithms and initial information can be input into the main control system  22  using the keyboard  318  or the portable computing device  326 . 
   The portable computing device  326  can be electrically connected to the irrigation unit  20  via the electrical interface  261 . In one embodiment, the portable computing device  326  includes a display screen that graphically displays with adjustable size the irrigation regions  30  and/or subregions  34  of the golf course  12 . For example, the display screen can display one of the subregions  34  in detail. The position of the irrigation unit  20  in the irrigation subregion  34  and the serial number of the irrigation unit  20  can be input into the irrigation unit  20 . Subsequently, the portable computing device  326  can control the unit control system  240  to use the subregion sensor  260  to locate the alignment guides  38  for the subregions  34 . Once the irrigation unit  20  locates the alignment guides  38 , the operator can control the irrigation unit  20  to irrigate the alignment guides  38 . If necessary, the software of the irrigation unit  20  is adjusted so that the irrigation unit  20  accurately irrigates the alignment guides  38 . This allows the irrigation unit  20  to accurately irrigate other areas of the subregion  34 . 
   Additionally, with the subregion  34  displayed on the portable computing device  326 , the operator can enter the features of each portion of the subregion  34 . For example, the operator can enter the vegetation, trees, greens, fairways, cart path, water features, etc., of the specific subregion  34 . In one embodiment, the irrigation unit  20  would be programmed not to irrigate the cart path. Another example would include programming the irrigation unit  20  to distribute more irrigation fluid  19  in a grass area than in a shrub area. 
   Once all of the subregions  34  in a specific irrigation region  30  have been programmed into the irrigation unit  20 , the irrigation unit  20  can be programmed for which subregions  34  of the irrigation region  30  get irrigated first—and for how long—to prevent runoff. In one example, a first subregion  34  can require approximately 15 minutes of irrigating. However, runoff occurs after five minutes. In this example, the irrigation unit  20  would be programmed to irrigate the first subregion  34  for five minutes. After five minutes of irrigating, the irrigation unit  20  starts irrigating a second subregion  34 . Subsequently, the irrigation unit  20  returns back to irrigate the first subregion  34  for another five minutes. This sequence is repeated until each subregion  34  is adequately irrigated. The sequencing would be continued until all of the subregions  34  have been programmed into the irrigation unit  20 . Next, the priority of when each irrigation unit  20  starts would be entered by the operator. In one embodiment, the irrigation units  20  would go on by themselves at the start of the designated time if the irrigation unit  20  determined that there was sufficient pressure of the irrigation fluid  19  for the irrigation unit  20  to operate. In one embodiment, for a golf course  12 , the irrigating start times and end times would be programmed in so as not to irrigate while golfers are in the vicinity, if possible. 
   Turning now to the automated operation of the irrigation system  10 , as set forth above, different irrigating sequences can be carried out by one or more algorithms which are dependent on information specific to, and gathered by, each irrigation unit  20 . The main control system  22  and unit control systems  240  of the irrigation system  10  of the present invention can use different types of algorithms to control the irrigating sequences performed by the individual irrigation units  20 . In one embodiment, the type of algorithm employed in the irrigation system  10  can depend on real-time, changing parameters. Another embodiment utilizes a second type of algorithm that is set and does not change on its own. Instead, this type of algorithm may be changed, or reprogrammed, by the main control system  22 , or manually by a system operator using the keyboard  316 , the portable computing device  326  or another suitable method. In one embodiment, both the main control system  22  and the unit control systems  240  use the algorithms that depend on changing parameters. Alternatively, the unit control systems  240  can use the set algorithms, while the main control system  22  uses an algorithm that depends on changing parameters. 
   In general, the unit control systems  240  can utilize algorithms to determine an irrigation sequence for the subregions  34  within the irrigation region  30  of a corresponding irrigation unit  20 . In contrast, the main control system  22  can control the overall operation, timing and sequence of the irrigation units  20  in an area of the golf course  12  (or other land area) such as a single golf hole  14 , a portion of a golf hole  14 , a portion of the golf course  12 , or the entire golf course  12 , as non-exclusive examples. Alternatively, the main control system  22  can also control the irrigation sequence for irrigation of the subregions  34  within one or more specific irrigation regions  30 . 
   Referring first to the algorithms used by the unit control systems  240 , in one embodiment, the unit control system  240  can be programmed to irrigate its respective irrigation region  30  in the following sequence: irrigate the subregions  34  with the highest elevations first, then irrigate the surrounding subregions  34  of these first-irrigated subregions  34 , and then irrigate progressively lower elevation subregions  34 . The algorithm used to perform the irrigation sequence could also take into consideration the slope of the subregions  34  in determining the quantity and/or flow rate of irrigation fluid  19  that is applied to the different subregions  34 . For example, when irrigating the subregions  34  surrounding the highest elevations, the amount of irrigation fluid  19  used would be reduced by a predetermined percentage to compensate for an expected quantity of irrigation fluid  19  runoff from the higher elevation subregions  34 . The percentage reduced can vary, and can be dependent upon the slope of the surrounding subregions  34 , for example, such that the greater the slope, the greater the reduction of irrigation fluid  19  output for the surrounding, lower-lying subregions  34 . 
   Other factors that the algorithm can take into account are, for example, the type of vegetation or grass in each subregion  34 , or the fact that the subregion  34  contains a feature that does not require irrigation fluid  19 , such as a cart path  16 H, sand trap  16 F, water feature  16 G, or other features that do not require irrigation. Thus, the unit control system  240  can determine that the subregions  34  within a specific irrigation region  30  require a disparate amount of irrigation fluid  19 , and that certain subregions  34  do not require any irrigation fluid  19 . With this design, the irrigation unit  20  can precisely control the quantity and/or flow rate of irrigation fluid  19  applied to different and/or adjacent subregions  34 . 
   For example, in alternative embodiments, the unit control system  240  can determine that approximately 5%, 10%, 25%, 50%, 75% or 100% greater irrigation fluid  19  is required as between different and/or adjacent subregions  34 . Alternatively, some other percentage difference between different and/or adjacent subregions  34  may be determined by the unit control system  240 . 
   The algorithm above is one of the set type of algorithms, since the sequence in which the subregions  34  are watered does not normally change. In an alternative embodiment the irrigating sequence could be based on an algorithm which depends on a real-time parameter such as the color of the grass or vegetation in each subregion  34 . In this example, the algorithm can utilize sensor readings on the color in each subregion  34 , and the irrigation sequence is carried out from lightest to darkest subregions  34 , or from darkest to lightest. In still other embodiments, the above described algorithms can also take into account weather factors, such as, for example, the temperature, humidity, barometric pressure, wind direction and speed, in determining the amount of irrigation fluid  19  to use, once the sequence is determined. 
   Additionally, since the unit control systems  240  can obtain the various weather and vegetation readings in real-time, the algorithms can compare the current reading with past readings to determine whether any adjustments need to be made in the irrigating sequence and/or the amount of irrigation fluid  19  used. Stated another way, the algorithms can take into account a change in the physical condition of one or more subregions  34  within the irrigation region  30  over time. 
   For example, when the irrigation unit  20  is not irrigating, on a predetermined periodic basis, the date, time of day, temperature, amount of visible light, wind speed, humidity, temperature of specific vegetation, color of specific vegetation and/or other relevant parameters within the irrigation region  30  can be measured and stored by the irrigation unit  20 . The algorithms stored in the unit control system  240  can use such past historical data along with current data (e.g. past 48 hours or some other suitable preset time period) in order to calculate the amount of irrigation fluid  19  required over time for each subregion  34  in the irrigation region  30 . 
   Moreover, the unit control system  240  or the main control system  22  can compare the calculations from a particular irrigation unit  20  over time to detect discrepancies indicative of a problem with the irrigation unit or the vegetation within the irrigation region  30 . For instance, if the calculated quantity of irrigation fluid  19  is being applied to a subregion  34 , yet the color of the vegetation within the subregion is inconsistent with the desired color within a set period of time, the unit control system  240  can identify a problem. In one embodiment, the amount of irrigation fluid  19  can be steadily adjusted, i.e. increased or decreased over time, as determined by the algorithm(s) programmed into the unit control system  240 , in order to achieve the desired color of vegetation. In the event the desired color is not achieved within a specified period of time as determined by the algorithm(s), the particular subregion  34  or irrigation unit  20  can be automatically or manually investigated for potential problems. 
   In this manner, the unit control systems  240  can be considered “smart systems,” since they are continuously learning and adapting the irrigation sequence based on previous irrigation fluid  19  usage data including times, quantity, and irrigation regions  30 , which is stored in the irrigation units  20 . Further, since the unit control systems  240  are in communication with the main control system  22 , the algorithms executed at the unit control systems  240  can request higher priority or additional irrigation fluid  19  from the main control unit  22  if the real-time measured conditions indicate that the algorithm calculations will not provide adequate irrigation for the irrigation region  30 . 
   Moreover, in one embodiment, the unit control system  240  can reestablish an irrigation sequence anew for its respective irrigation unit  20  on a periodic basis. For example, the unit control system  240  can reevaluate and recalculate an appropriate irrigation sequence at least approximately once every 24 hours. In alternative embodiments, the unit control system  240  can determine an appropriate irrigation sequence more or less often than one every 24 hours. 
   In the above examples, the priority or sequence of when each irrigation unit  20  is operated can be programmed from the main control system  22  as determined by a system operator. For example, the irrigation units  20  can be grouped based on the type of region of the golf course  12 , such as the fairways  16 C, the greens  16 E, and/or other areas. The different groups are assigned priority levels by the operator and programmed by the main control system  22  to the units  20 . The main control system  22  would control the starting times for each group to begin its irrigation sequence. In one embodiment, the irrigating times would be times when the golf course  12  is not in use. At the programmed starting time, the irrigation units  20  in each group would start its programmed irrigating sequence if it is determined that there&#39;s sufficient pressure of irrigation fluid  19  to begin irrigation. However, these set times can be overridden if it is necessary to provide additional irrigation times due to extreme weather conditions, such as high temperatures, low humidity, etc. This can be done manually by a system operator, or alternatively, the unit control systems  240  can be programmed to run the algorithms whenever their sensors record information that the temperature or humidity on the golf course  12  has reached a specific threshold value. In this case, the unit control system  240  can communicate with the main control system  22 , which can then decide whether or not the previously unscheduled irrigating should be performed. 
   In another embodiment, the algorithm for irrigating can be dependent upon the following parameters: temperature of the grass or vegetation, relative humidity, color of the grass or vegetation, amount of sunlight, time of day, time of year, irrigating requirements for the type of ground covering, wind conditions, or other suitable parameters. At preprogrammed times, the irrigation unit  20  can measure the temperature, amount of light, wind conditions and humidity at the unit  20 , the temperature and/or color of the ground covering in the subregion  34 . The unit control system  240  calculates an amount of irrigation fluid  19  necessary for the subregion  34  based on the temperature, amount of light, wind conditions and humidity at the irrigation unit  20 , and an amount of irrigation fluid  19  based on the temperature and color of the grass. 
   In one embodiment, once the appropriate quantity of irrigation fluid  19  has been calculated for a subregion  34 , only a certain percentage (for example, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90%) of the calculated quantity is applied over the subregion  34 . The temperature and/or color of the grass is then checked and if an acceptable temperature and/or color are measured, irrigating is concluded (up to 100%) for that subregion  34 . However, if the measured temperature and/or color are not acceptable, then an additional percentage (for example, another 10%, 20%, 30%, 40% or 50%) of the calculated fluid is applied over the subregion  34 . The irrigation unit  20  continues to take the measurements and apply irrigation fluid  19  in this manner until acceptable measurements are obtained or until the irrigation quantity exceeds the calculated amount by a certain predetermined percentage. If the latter occurs, the unit control system  240  reports to the main control system  22  that there may be a problem at that subregion  34  or irrigation unit  20  serving that subregion  34 . 
   In the above example, the algorithm includes a troubleshooting routine which tries to ensure that the proper amount of irrigation fluid  19  is being applied for the conditions and type of grass in the subregion  34 . This is accomplished by repeatedly monitoring the temperature and color of the subregion  34  after applying irrigation fluid  19  to the subregion  34  and if the monitored temperature and/or color are not acceptable, more irrigation fluid  19  is applied. After some point however, when the temperature and/or color are still not within an acceptable range, the unit control system  240  communicates a problem to the main control system  22 . The main control system  22  can then notify a system operator that there is a problem with the specifically numbered irrigation unit  20 , and the irrigation unit  20  can be disabled until it can be manually troubleshooted or otherwise repaired. Alternatively, the problem can be flagged for that irrigation unit  20  and it will continue watering at the previous rates adjusted in accordance with the measured sensor readings until maintenance corrects the problem. 
   Additionally, the unit control system  240  can use an algorithm that uses the same parameters, but which also takes into account previous readings of those parameters at past times/days/hours, in order to calculate the amount of irrigation fluid  19  that should be applied. By continuously using the information from previous irrigation sequences, the unit control system  240  is a “smart system” to provide more efficient and optimized irrigation to a given area. 
   Algorithms have been described herein as being executed by the unit control systems  240  and others by the main control system  22 . One skilled in the art would recognize that the main control system  22  could perform all control algorithms. Similarly, the unit control systems  240  can perform the control algorithms carried out by the main control system  22 , other than the overall sequencing algorithm. 
   While the particular embodiments of the automated irrigation system  10  and the irrigation units  20  as illustrated herein are fully capable of satisfying the needs and providing the advantages herein before stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.