 |
Claims  |
|
|
What is claimed is:
1. A method of controlling irrigation, comprising the steps of:
locating a plurality of irrigation controllers, each for irrigation of a
crop having an associated crop adjustment value, in a plurality of
Evapotranspiration zones, each said irrigation controller including means
for recording an Evapotranspiration zone reference and means for recording
a crop adjustment value;
recording a particular one of said plurality of Evapotranspiration zones in
said Evapotranspiration zone reference recording means of each irrigation
controller within said particular Evapotranspiration zone;
recording said associated crop adjustment value in said crop adjustment
recording means;
receiving a broadcast Evapotranspiration data signal at each of said
plurality of irrigation controllers, said Evapotranspiration data signal
including a plurality of Evapotranspiration zone identifiers and
corresponding Evapotranspiration values;
comparing, at each irrigation controller, received Evapotranspiration zone
identifiers with said Evapotranspiration zone reference stored in each
particular controller until a particular one of said Evapotranspiration
zone identifiers matches said Evapotranspiration zone reference to produce
a match;
scaling, when a match is found, said Evapotranspiration value corresponding
to said particular one Evapotranspiration zone identifier with said crop
adjustment value recorded in said irrigation controller; and
adjusting an irrigation flow quantity to about equal said scaled
Evapotranspiration value.
2. A method of controlling irrigation sprinklers using broadcast
Evapotranspiration data, comprising the steps of:
broadcasting an Evapotranspiration data signal to a collection of receivers
coupled to a plurality of irrigation flow controllers, said
Evapotranspiration data signal containing a plurality of coded
Evapotranspiration zone identifiers and corresponding coded
Evapotranspiration values, each of said collection of receivers including
means for storing an Evapotranspiration zone reference and a crop
adjustment value;
receiving said Evapotranspiration data signal;
decoding said Evapotranspiration data signal to produce a plurality of
decoded Evapotranspiration zone identifiers and corresponding
Evapotranspiration values;
comparing each of said decoded Evapotranspiration zone identifiers with
said Evapotranspiration zone reference; and
adjusting an irrigation flow quantity of particular ones of said plurality
of flow controllers having said Evapotranspiration zone references
matching a particular one of said decoded Evapotranspiration zone
identifiers to about equal a product of a particular one of said
Evapotranspiration values corresponding to said particular one decoded
Evapotranspiration zone reference and said crop adjustment value.
3. The method of claim 2 wherein said broadcasting step comprises direct
broadcasting from a geosynchronous communications satellite.
4. The method of claim 2 wherein said broadcasting step comprises direct
broadcasting via FM subcarrier transmissions.
5. The method of claim 2 wherein said broadcasting step comprises direct
broadcasting over a paging network.
6. The method of claim 2 wherein said broadcasting step includes encrypting
Evapotranspiration broadcasts prior to broadcast and wherein said
receiving step includes the step of decrypting said encoded information.
7. A system for controlling irrigation sprinklers using broadcast
Evapotranspiration data, comprising:
means for broadcasting an Evapotranspiration data signal to a collection of
receivers coupled to irrigation flow controllers, said Evapotranspiration
data signal containing broadcast coded Evapotranspiration zone identifiers
and broadcast coded corresponding Evapotranspiration value, each of said
collection of receivers including means for storing a Evapotranspiration
zone reference and a crop adjustment value;
means for receiving said Evapotranspiration data signal;
means, coupled to said receiving means, for decoding said
Evapotranspiration data signal to produce a plurality of decoded
Evapotranspiration zone identifiers and corresponding Evapotranspiration
values;
means, coupled to said decoding means, for comparing each of said decoded
Evapotranspiration zone identifiers with said Evapotranspiration zone
reference; and
means, coupled to said comparing means, for adjusting an irrigation flow
quantity of said plurality of flow controllers having said
Evapotranspiration zone references matching a particular one of said
decoded Evapotranspiration zone identifiers to about equal a product of a
particular one of said Evapotranspiration values corresponding to said
particular one decoded Evapotranspiration zone reference and said crop
adjustment value.
8. The system of claim 7 wherein said means for broadcasting comprises a
geo-synchronous communications satellite capable of direct broadcast to
earth-based receivers.
9. The system of claim 7 wherein said means for broadcasting comprises a
means for broadcasting using FM subcarriers.
10. The system of claim 7 wherein said means for broadcasting comprises a
means for broadcasting over a preexisting paging network.
11. The system of claim 6 wherein said means for receiving said
Evapotranspiration data signal and said means for adjusting irrigation
flow responsive to said crop control code comprise an integral receiving
and controlling unit.
12. The system of claim 6 wherein said means for broadcasting includes
means for encrypting said Evapotranspiration data signal and wherein said
means for receiving includes means for decrypting said encoded
Evapotranspiration data signal.
13. A method of controlling irrigation sprinklers by receiving and
processing FM subcarrier broadcasts of Evapotranspiration data to control
automatically a set of irrigation sprinklers, said method comprising the
steps of:
directly broadcasting an Evapotranspiration data signal from a transmitter;
receiving said Evapotranspiration data signal at a receiver;
coupling said Evapotranspiration data signal from said receiver to an
irrigation flow controller having a preset duty cycle for watering; and
adjusting said preset duty cycle responsive to said Evapotranspiration data
signal to provide an adjusted duty-cycle signal.
14. A system for regulating sprinkler controllers using direct broadcast of
Evapotranspiration data, said system comprising:
means for directly broadcasting an Evapotranspiration data signal;
receiving means for receiving said Evapotranspiration data signal;
an irrigation sprinkler controller having a preset duty cycle for watering;
means for coupling said Evapotranspiration data signal from said receiving
means to said irrigation sprinkler controller;
means for adjusting in said irrigation sprinkler controller said preset
duty cycle for watering responsive to said Evapotranspiration data signal
to provide an adjusted duty-cycle signal, whereby said irrigation
sprinkler controls the amount of water sent to plants according to said
adjusted duty-cycle signal.
15. A system for directly broadcasting selected portions of an
Evapotranspiration database to a collection of receiving and
sprinkler-controlling units distributed over a geographic area, each
receiving and sprinkler-controlling unit being coupled to at least one
irrigation sprinkler, said system comprising:
means for directly broadcasting a stream of encrypted Evapotranspiration
data;
a plurality of irrigation sprinkler controllers, each of said controllers
having a preset duty cycle for watering;
a plurality of receiving means for receiving said encoded
Evapotranspiration data signal, each of said receiving means being coupled
to at least one of said irrigation sprinkler controllers, and each
receiving means including means for storing a preset Evapotranspiration
zone reference and for storing a preset crop adjustment value;
each of said receiving means also including means for decrypting said
encrypted irrigation control signal into a broadcast Evapotranspiration
zone identifier and a broadcast corresponding Evapotranspiration value;
each of said receiving means coupled to irrigation sprinkler controller
means including means of comparing said broadcast Evapotranspiration zone
identifier with said preset Evapotranspiration zone reference such that
each of said sprinkler controllers is selectively responsive to a
corresponding one of said Evapotranspiration values of one of said zone
identifiers;
means for coupling said Evapotranspiration data signal from each of said
receiving means to said irrigation sprinkler controllers;
means for adjusting in said irrigation sprinkler controllers said preset
duty cycles for watering responsive to said Evapotranspiration data
signals and also responsive to said preset crop adjustment value to
provide adjusted duty-cycle signals, whereby said each of said irrigation
sprinkler controllers controls the amount of water sent to plants
according to said adjusted duty-cycle signal.
16. A method of distributing Evapotranspiration information for a plurality
of Evapotranspiration zones over a distributed geographic area for
automatic adjustment of watering intervals for irrigation flow
controllers, comprising the steps of:
compiling a database of a plurality of Evapotranspiration values for each
of the plurality of Evapotranspiration zones;
matching each of said plurality of Evapotranspiration values with its
corresponding Evapotranspiration zone to produce a set of
Evapotranspiration zones having corresponding Evapotranspiration values;
and
broadcasting periodically said set of Evapotranspiration zones with
corresponding Evapotranspiration values. |
|
 |
|
 |
Claims |
|
|
|
Description |
|
|
BACKGROUND OF THE INVENTION
The present invention relates to the use of irrigation sprinkler
controllers. More particularly, the invention relates to the reception and
use of Evapotranspiration data by irrigation sprinkler controllers.
Irrigation is the artificial application of water to soil to promote plant
growth. The practice dates back at least to the canals and reservoirs of
ancient Egypt. Today, farmers and others irrigate hundreds of millions of
acres of farmland throughout the world, most notably in the U.S., India,
Pakistan, China, Australia, Egypt, and the USSR.
In the past, irrigation sprinkler controllers were often unwieldy and
expensive. As a result, many agriculturalists erred in the direction of
overwatering their crops to provide a margin of safety. Although
overwatering adequately protects the crop investment, increased public
concern over water consumption requires that agriculturalists cease this
wasteful practice.
Modern methods have brought an increasing measure of control over the rate
and timing of irrigation. Recent advances allow agriculturalists to make
cost-effective timing adjustments on many remote sprinkler controllers.
Marian (U.S. Pat. No. 4,962,522), issued to the present inventor,
exemplifies modern designs for irrigation control systems. The present
description incorporates Marian by reference. Marian provides an apparatus
and method for remotely controlling irrigation at one or more sites. The
user need only periodically calculate an adjustment value to change preset
values and then inform a central system. The central system, in turn,
delivers the adjustment information via transmissions at commercial paging
frequencies to individual sprinkler controllers.
Modernly, an agriculturalist calculates the proper sprinkler adjustment
value by referring to Evapotranspiration (ET) data. The ET value
represents the total water loss from the soil and vegetation over a
predefined period. This water loss includes water lost by direct
evaporation and by transpiration from the plant surfaces.
Thus, the ET value provides an indication of an amount of water that an
irrigation system must replenish to maintain the plants in an unstressed
condition. The ET value, often expressed in inches of water, depends on
local weather information. A large state, such as California, can have
thousands of different ET zones, each having its own dynamic ET values.
Measurement of water loss for one particular plant species established a
normalized ET value. Each plant material has a crop adjustment value used
to scale the normalized ET value. The scaled normalized ET value
customizes the ET value for each particular plant species. An example of a
common crop adjustment value used with ET values is a crop coefficient
(K.sub.c). The crop coefficient (K.sub.c), expressed as a percentage,
scales a particular ET value to provide a water quantity for the
particular crop. The crop coefficient (Kc) can vary over time, depending
upon particular seasons and a plant's water requirement for flowering or
bearing fruit, for example. A number of references: Blaney, H. F., et al.,
(Aug. 1950), "Determining Water Requirements in Irrigated Areas from
Climatological and Irrigation Data," U.S. Dept. of Agri. Soil Conserv.
Service, pp. 1-48; Penman, H. L., (1948), "Natural Evaporation from Open
Water, Bare Soil and Grass," Proceedings, Royal Soc., Series A., Vol. 193,
pp. 120-145; Jensen, M. E., (Dec., 1963), "Estimating Evapotranspiration
from Solar Radiation," J. Irrig. and Drainage Div., pp. 15-41; Jensen, M.
E., (Sep., 1983), Design and Operation of Farm Irrigation Systems,"Am.
Soc. Agri. Eng., No. 3, pp. 1-232; and "How Much Water Does Your Lawn
Really Need," Sunset, (Jun. 1987), pp. 213-219; hereby incorporated by
reference for all purposes, are suitable as a background source on ET and
calculation of ET values.
ET has rapidly become a water-use standard--regulatory bodies in some areas
demand that agriculturalists conduct irrigation only through use of ET
values. In such areas, harsh penalties attach to water use which exceeds
ET values. Such penalties provide impetus for users to limit their water
use.
Many local variables, including temperature, humidity, wind, net solar
radiation, soil temperature, and precipitation can affect the calculation
of the ET value for a particular zone. Accordingly, agriculturalists must
get extremely detailed and accurate weather profiles at regular intervals.
Fortunately, governmental agencies usually provide ready access to ET
information to users in states which are heavily dependent on irrigation.
The government provides for user access to the ET data in several ways.
One avenue of user access to local ET data involves use of a personal
computer and a modem to connect to a central government database. This
user-intensive procedure requires the user to gain access to ET
information and then to calculate the sprinkler adjustment value for each
controller. If users have extensive irrigation requirements that span
several ET zones and employ many controllers, this method can be
time-consuming and error-prone.
Another avenue for supplying ET information is for local water control
agencies to provide such information via daily phone recordings. Still
another method of distributing ET values is publication in local
newspapers or other periodicals. Again, these methods require a user to
gain access to information and to calculate the adjustment value. Any
particular publication may not cover ET zones that are not in a local
area. The user must still search out the information, perform necessary
calculations, and manually enter necessary changes, for each zone and
controller. As the number of zones and the concomitant number of
irrigation controllers increases, these solutions become increasingly
cumbersome and inefficient.
A modern design, such as offered by U.S. Pat. No. 4,962,522 (Marian),
represents a significant improvement in the art of irrigation controller
design. It is now possible to control remote irrigation controllers daily.
Nevertheless, such a controller is still dependent on human interaction,
particularly in accessing, extracting and using desired ET values, as
modified by the crop coefficient (Kc). The U.S. Pat. No. 4,962,522 patent
does not address the problem and does not solve the heavy user demands
problem.
A human being must still (1) access current ET information for each
controller under his dominion. The user must then (2) calculate (either by
hand or processing means) a proper sprinkler adjustment value responsive
to the accessed ET data. Finally, the user must (3) enter the latest
sprinkler adjustment value to a system for broadcast delivery to a
collection of sprinkler controllers.
Thus, modern controllers are still dependent on humans to gain access to ET
data periodically, to calculate an adjustment value, and to deliver the
adjustment value. In fact, when an agriculturalist must access, calculate,
and deliver information to hundreds of sprinkler controllers, such human
interaction remains a burdensome and formidable task.
Accordingly, there is a need for an ET-data-based method and apparatus for
controlling irrigation through access, calculation, and delivery of ET
information to multiple controllers.
SUMMARY OF TUE INVENTION
The present invention provides a method and apparatus for controlling
irrigation to replace water lost by evaporation and by transpiration.
More particularly, an embodiment of the present invention broadcasts coded
ET values and corresponding ET zones directly to a collection of
intelligent, microprocessor-based irrigation sprinkler controllers located
over a wide geographic area. These controllers then produce an adjustment
value responsive to the broadcast ET data for a particular ET zone.
It is an object of the invention to broadcast ET information directly to
sprinkler controller sites. Thus, the invention bypasses the need for a
human to gain access to ET information.
It is another object of the invention to end the need for a human being to
calculate adjustment values.
It is yet another object of the invention to remove the need for delivering
adjustment values to a sprinkler system.
It is yet another object of the invention to provide a system for
broadcasting ET data directly to remote sprinkler controllers.
Other advantages and features of the invention will become apparent after
considering the following drawings and detailed description.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a graphical illustration of an irrigation control system 10 which
shows a transmitter 12 in communication with a collection of receiver
units 14 and receiver/controller units 16; and
FIG. 2 is a flow diagram showing the various steps in the method according
to the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
Modern controllers, such as Marian (U.S. Pat. No. 4,962,522), allow
agriculturalists to adjust irrigation sprinkler controllers from a remote
location. A user merely accesses updated ET information, calculates an
adjustment value, and sends the adjustment value information to a central
system. The central system, in turn, sends the information to the
sprinkler controllers.
The present invention removes the human link from the process of remotely
controlling irrigation sprinklers. The method and apparatus provided
allows for the updated ET information to be broadcast directly to
receivers coupled to irrigation sprinkler controllers distributed over a
wide geographic area that includes several ET zones. Several well-known
broadcast systems are suitable for sending the encoded ET information
periodically. In the preferred embodiment, the ET information is broadcast
directly over an FM subcarrier to a microprocessor-based receiver equipped
to receive and decode such signals. Other broadcast methods, such as
direct satellite transmission or preexisting paging systems, for example,
could be used.
A special receiver selectively receives the ET broadcast, meaning that the
receiver only responds to ET information for a particular preset zone. In
the preferred embodiment, the receiver is microprocessor-based.
The receiver extracts ET information associated with the particular zone
and automatically adjusts the sprinkler intervals to deliver the proper
amount of water. The sprinkler controller is responsive to the updated ET
information and is also responsive to preset crop- and irrigation-specific
information about the particular crop, that is, the crop coefficient (Kc).
The system is fully automatic, requiring negligible intervention by the
various users.
FIG. 1 illustrates a system 10 for directly broadcasting, by a transmitter
12, selected portions of an ET database to a collection of
remotely-located receiving units 14 and sprinkler-controlling units 16.
The receiving units 14 interface with a sprinkler controller 20 to control
an irrigation flow, such as from a sprinkler 22, for example. The
sprinkler-controller 16 integrally combines a receiving unit 14 and
sprinkler controller 20.
The ET database contains ET values for various ET zones distributed over a
wide geographic area. For purposes of illustration only, California is
shown having five ET zones. Different ET values are generally applicable
to each of the ET zones. The reader will understand that many thousands of
zones exist, with many tens and hundreds of thousands individual receivers
14 and receivers-controllers 16 distributed in these zones. Each receiver
14 and receiver-controller 16 includes a prestored ET zone reference, as
well as a crop coefficient (K.sub.c). The receiver 14 and
receiver-controller 16 control their respective irrigation flow
controllers (e.g. sprinklers 22) responsive to a K.sub.c scaled ET value
corresponding to an ET zone identifier in the broadcast matching the
prestored ET zone reference.
In operation, the transmitter 12 periodically broadcasts a stream of coded
ET zone identifiers, and corresponding coded ET values. Coding includes
both a digitizing of the ET zone identifiers and corresponding ET values,
as well as an encryption of the ET information broadcast to the various
receivers 14 and to the receiver-controllers 16.
Each receiver 14 and receiver-controller 16 decodes the periodic
broadcasts, waiting for an ET zone identifier matching the preset ET zone
reference. When a match occurs, the receiver 14 (receiver-controller 16)
uses the corresponding decoded ET value. The receiver 14 and
receiver-controller 16 scale the ET value by the crop coefficient K.sub.c
to produce a value corresponding to an amount of water (in inches) the
sprinklers 22 are to apply to the crops.
FIG. 2 is a flow diagram showing the various steps in operation of a
receiver-controller I6 according to a preferred embodiment of the
invention. Step 100 through step 105 identify a set of steps for
automatically controlling an irrigation flow for a plurality of sprinklers
distributed over a wide-geographic area including many ET zones.
Step 100 begins the process. The receiver-controller 16 receives an ET
broadcast stream of coded ET information at step 101. At step 102, the
receiver-controller 16 decodes each of the ET zone identifiers, and
preferably the corresponding ET values, as they are received. For each
decoded ET zone identifier, the receiver-controller 16 determines if any
one particular decoded ET zone identifier matches with a stored preset ET
zone reference. If the receiver-controller 16 determines that the ET zones
do not match, the receiver-controller 16 returns to step 102 to decode the
next ET zone identifier. This loop of steps 102 and 103 continues until an
ET zone occurs. Matching advances the process to step 104 which scales the
ET value corresponding to the matched ET zone identifier. Scaling in the
preferred embodiment results from a product of the prestored crop
coefficient (K.sub.c) and the ET value. The resulting number, a quantity
of water expressed in inches, is provided to a sprinkler controller
portion of the receiver-controller 16. At step 105, the
receiver-controller 16 adjusts irrigation flow to correspond to the scaled
ET value. After adjusting the flow, the receiver-controller 16 returns to
step 101, waiting for the next ET update. To promote reliability of the
system 10, the transmitter 12 issues redundant broadcasts of ET data.
Typically the ET values are updated every day, but less frequent updates
are believed acceptable. Thus, the receiver-controller 16 must
discriminate redundant broadcasts to provide the specified water amount.
The preferred embodiment discriminates the redundant transmissions by
letting the scaled ET value update a watering interval to be used when the
receiver-controller 16 normally would initiate irrigation flow. The
broadcast does not initiate the irrigation in the preferred embodiment,
but updates an interval used for the preset irrigation control timings.
The reader will understand that the preferred embodiment requires that the
receiver-controller 16 be set to deliver a prespecified amount of water
(inches) for a particular watering period. The receiver-controller 16
could then directly use the scaled ET value. For example, if the
receiver-controller 16 operates the sprinklers for one-half hour for 1.00"
of water, a scaled ET value of 0.50" would cause the sprinklers to
operate for one-quarter hour. Other variations of timing are possible,
depending upon the type of irrigation flow control.
Other refinements add to the range of use of the present invention. For
example, the receiver may be part of a display unit which continuously
displays one or more ET values associated with preselected ET zones. This
display unit would continuously display the ET value for a present ET zone
reference entered into the unit. An operator could make use of the ET
value in many different ways.
While the above-described invention refers to a specific apparatus, skilled
artisans will recognize that various other applications and alterations
are obvious. The spirit and scope of the invention encompass such other
applications and alterations. Only the appended claims limit the scope of
the present invention.
* * * * *
|
|
|
|
|
|
|
Description |
|
