WO2001028314A1

WO2001028314A1 - Texture based inferred switching for irrigation scheduling and operational method

Info

Publication number: WO2001028314A1
Application number: PCT/AU2000/001306
Authority: WO
Inventors: James Dunstone Townsend
Original assignee: Irrigation Control Networks Pty Ltd
Priority date: 1999-10-21
Filing date: 2000-10-23
Publication date: 2001-04-26
Also published as: CA2387752A1; NZ518332A; AU1116001A; AU772133B2; AUPQ357799A0

Abstract

The present invention provides a method for remote management of a plurality of irrigation sites, each site having a receiving device in communication with one or more switching devices for controlling irrigation of the site, the method comprising the steps of: (a) establishing a number of soil moisture models, each site being associated with an appropriate model; (b) for each model: (i) making progressive estimates of soil moisture content; and (ii) determining whether the soil moisture content has fallen below a refill point for the model; and (c) for each model in respect of which the soil moisture content has fallen below the refill point, communicating an irrigation signal to the receiving devices of all sites associated with the model to initiate, or enable, irrigation of those sites; wherein each model is adapted to control the irrigation of any number of sites associated with the model. The invention also provides a distributed system and associated apparatus for implementing the method.

Description

Texture based inferred switching for irrigation scheduling and operational method

Field of the invention

The invention relates to irrigation control systems for remote management of irrigation sites, and for methods for the operation thereof.

Background of the invention

Controllers for starting and stopping irrigation cycles without human intervention are well known. Many such controllers are able to manage irrigation sites having a number of valves by opening and closing the valves in a programmed succession for various times. Many of the known controllers are capable of storing and executing more than program.

A problem of many such known controllers is that they are capable only of repeating the program or programs without any ability to respond to weather conditions including rain. Consequently, such controllers tend to produce considerable wastage of water.

In international application numbers PCT/AU97/00056 and PCT/AU99/00175, the present inventor has taught methods and apparatus that provided advances over the then prior art. The disclosure and teachings of each of these patent specifications is incorporated herein by reference.

A drawback of many presently known methods of irrigation control lies in the need to survey the irrigation sites to at least some degree in order to determine relevant site details and have them entered into a database associated with the irrigation management method to enable irrigation management decisions to be made on a site-by-site basis. This requirement may add cost and inconvenience to these techniques and may make them difficult to apply to small irrigated areas (of which there are many). In particular, the need to survey the irrigation site can represent a significant impediment to having individual home owners subscribe to irrigation management services. However such individuals are nevertheless cumulatively responsible for considerable water wastage.

Objects of the invention

It is an object of the present invention to ameliorate some or all of the above disadvantages. In particular, it is an object of some aspects of the present invention to reduce the degree of detailed site survey required before a person responsible for the management of an irrigation site can subscribe to an irrigation management service. It is a further object of some aspects of the present invention to provide an improved or different irrigation management tool for the provider of an irrigation management service wherein it is not necessary to make irrigation management decisions on a site-by-site basis.

Summary of the invention According to an aspect of the present invention, there is provided a method for remote management of a plurality of irrigation sites, each site having a receiving device in communication with one or more switching devices for controlling irrigation of the site, the method comprising the steps of:

(a) establishing a number of soil moisture models, each site being associated with an appropriate model;

(b) for each model:

(i) making progressive estimates of soil moisture content; and

(ii) determining whether the soil moisture content has fallen below a refill point for the model; and (c) for each model in respect of which the soil moisture content has fallen below the refill point, communicating an irrigation signal to the receiving devices of all sites associated with the model to initiate, or enable, irrigation of those sites; wherein each model is adapted to control the irrigation of any number of sites associated with the model. This method enables the provider of an irrigation management service to run a number of models that are representative of the irrigation sites for which the service provider is responsible without requiring irrigation management decisions to be made on a site-by-site basis.

The communication may be by any suitable means. It may take place over the Internet. It may use telephone signals, including mobile telephone signals.

The irrigation signal in respect of a model may be transmitted both to receiving devices of sites associated with the model and to receiving devices of sites that are not associated with the model. In this case the transmission must include a model identifier interpretable by the receiving devices for determination of whether the irrigation signal is applicable to the site. In a preferred form of the present invention, each soil moisture model of the method is defined by:

(a) a soil texture identifier selected from a predetermined list of soil texture identifiers;

(b) a sector identifier selected from a predetermined list of sector identifiers; and (c) a refill point; each site being associated with a model having the appropriate soil texture identifier, sector identifier, and refill point for the site.

By limiting the inputs defining the models to these, a person responsible for the management of an irrigation site may subscribe to an irrigation site management service without needing to undertake any detailed site survey. Similarly, the service provider need not undertake any detailed site survey.

Any suitable refill point may be used. A refill point of 0.4 (ie. 40% of soil moisture capacity) is typically suitable.

The sector identifier is any suitable identifier for specifying the location of the irrigation site.

The method may provide identifiers for any suitable soil types, eg. sand, loam, clay, etc.

The soil moisture model may be further defined by a vegetation type identifier selected from a predetermined list of vegetation type identifiers, each site being associated with a model having the appropriate soil texture identifier, sector identifier, vegetation type identifier and refill point for the site.

This addition to the inputs defining the models likewise does not require any detailed site survey to be undertaken. Typically the available vegetation type identifiers will include a choice of common crop types.

The estimated soil moisture content for the model is preferably determined by a calculation that produces substantially the same result as estimating a maximum soil moisture content for the model and making adjustments for moisture loss from, and for moisture addition to, the model. In this case, the soil moisture loss for the model is preferably estimated in dependence on meteorological data measured in respect of the model's sector. The meteorological data may include solar radiation data. These soil moisture models may be further defined by a harshness factor selected from a predetermined list of harshness factors, wherein the soil moisture loss for a model is adjusted in dependence on the harshness factor.

The soil moisture content estimates for a model are preferably determined in dependence on an estimated root zone depth for the model, the estimated root zone depth for the model being determined in dependence on the model's soil texture identifier. The estimated root zone depth for the model may also be also determined in dependence on the model's vegetation type identifier. The estimated root zone depth for the model may also be also determined in dependence on the model's sector identifier.

Preferably, the maximum soil moisture content for a model is determined in dependence on the product of the estimated root zone depth for the model and an estimated soil moisture holding capacity for the model.

In this way, the use of standardised models with typical root zone depths allows remote irrigation management to be effected without the need to undertake surveys to determine the root zone depth of a site. In particular, once a standardised root zone depth is determined for a model, the factor governing the frequency of irrigation is soil texture.

The soil moisture addition for a model preferably includes rainfall data measured in respect of the model's sector. The rainfall data may be, or be based on, Doppler radar data.

The soil moisture addition for a model preferably includes a standard amount of water assumed to be applied during irrigation. Typically, the standard amount is sufficient water to raise the soil moisture content of the model to the maximum soil moisture content for the model. In this case, the method may provide that following receipt by a receiving device of an irrigation signal applicable to a site, the receiving device causes its switching device or devices to irrigate for a time sufficient to add the standard amount of water to the site. The method preferably provides that for each model in respect of which rain is detected or forecast in the model's sector, an irrigation halt signal is communicated to the receiving devices of all sites associated with the model.

According to another aspect of the present invention, there is provided a distributed system for remote management of a plurality of irrigation sites, the system comprising: (a) a receiving device in communication with one or more switching devices for controlling irrigation of each site; (b) a host computer system having memory containing a computer program and being adapted to execute the computer program, the computer program embodying a number of soil moisture models, each site being associated with an appropriate model, wherein the logic underlying each model involves: (i) making progressive estimates of soil moisture content; and

(ii) determining whether the soil moisture content has fallen below a refill point for the model; the host computer system being adapted to communicate an irrigation signal to the receiving devices of all sites associated with the model to initiate, or enable, irrigation of those sites following the program determining that the soil moisture content of a model has fallen below the refill point for the model; wherein each model is adapted to control the irrigation of any number of sites associated with the model.

The host computer system of the distributed system is preferably adapted to transmit an irrigation signal in respect of a model both to receiving devices of sites associated with the model and to receiving devices of sites that are not associated with the model, the transmission including a model identifier interpretable by the receiving devices for determination of whether the irrigation signal is applicable to the site.

The soil moisture models embodied in the distributed system may be as described above in relation to the method of the present invention.

The distributed system is preferably configured such that following receipt by a receiving device of an irrigation signal applicable to a site, the receiving device causes its switching device or devices to irrigate for a time sufficient to add a standard amount of water to the site. In this case, the soil moisture addition for a model must include the standard amount of water assumed to be applied during irrigation. Typically, the standard amount is sufficient water to raise the soil moisture content of the model to the maximum soil moisture content for the model.

Preferably the distributed system is configured such that if rain is detected or forecast in a sector of a model, the host computer system communicates an irrigation halt signal to the receiving devices of all sites associated with the model. In another aspect the present invention provides for a host computer system as described in relation to the distributed system.

According to a further aspect of the present invention, there is provided a receiving device for communicating with one or more switching devices and being adapted to control irrigation of an irrigation site, the receiving device being adapted to receive an irrigation signal to initiate, or enable, irrigation, and to receive an irrigation halt signal to cause irrigation to cease, the receiving device having model identification means for determining whether a received signal carrying a model identifier is applicable to the receiving device.

The model identification means of the receiving device may be a computer executing a computer program for model identification. It may be a dip switch or the like.

The receiving device preferably has a soil texture identifier entry means for entering a soil texture identifier. The receiving device preferably has a sector identifier entry means for entering a sector identifier. The receiving device preferably has a refill point entry means for entering a refill point. The receiving device preferably has a vegetation type identifier entry means for entering a vegetation type identifier. The receiving device preferably has a harshness factor entry means for entering a harshness factor. The receiving device preferably has an irrigation system precipitation rate entry means for entering an irrigation system precipitation rate.

The identifier entry means, refill point entry means or irrigation system precipitation rate entry means may be a dip switch, a series or dip switches, or the like. They may be a keyboard or keypad.

In another aspect the present invention provides a receiving device as described which is adapted to be retrofitted to an existing irrigation controller.

Description of one preferred embodiment The invention will now be further explained and illustrated by reference to the accompanying drawing in which figure 1 shows a flow diagram of steps involved in establishing a distributed system according to the invention.

A prospective user already irrigates a site (such as a lawn or garden area) using an irrigation controller already purchased, installed and commissioned. Following learning of the service according to the present invention, the prospective user obtains from the service provider a receiving device for connection to the existing controller. The user then installs the receiving device by connecting an interface provided with the receiving device to the user's existing controller, as indicated at 10 in figure 1.

The user then configures the receiving device as indicated at 20 in figure 1 , by entering the following parameters and identifiers into a console provided on the receiving device. From a list of soil textures and sectors provided to the user, such as via the service provider's website, the user identifies the soil texture identifier and sector identifier appropriate to the user's application. The user then enters these details into the receiving device via the console.

The user also calculates the system precipitation rate for the user's irrigation system, and enters this into the receiving device via the console. Next, the user selects a harshness factor from the list of "harsh", "less harsh" or "about average for the sector", in order to allow the user to fine tune operations. Entry of a harshness factor could also be used to differentiate between the likely evapotranspirative rate of plants from differing parts of an area. The harshness factor is entered into the receiving device via the console. Once all these details have been entered, the display of the receiving device will confirm the parameters selected (sector, texture etc).

Having thus set up the system, the user then advises the service provider of the following information, as indicated at 30 in figure 1 :

• serial number of the user's receiving device or some other suitable identifier; • the sector

• the texture

• the harshness factor

As indicated at 40 in figure 1, the service provider stores this information on its host computer system in order to have a record that a model covering the user's site parameters must be maintained. (Although a modern computer can easily accommodate the task of running a model for every combination of site parameters, nevertheless needless computation and/or transmission of data would inflate costs.) Therefore as each user registers his sector, texture and status, if not already activated, the appropriate model would be activated and executed (as indicated at 50 in figure 1). From then on the user's receiving device would receive data as relevant and would irrigate the user's site in accordance with weather/climatic requirements and would stop irrigation if rain fell or threatened. Such rain would of course be recorded by the system and would be "harvested" thus delaying subsequent irrigation. The receiving device may be configured to display the following information:

• the amount of water remaining before irrigation will be necessary (this may be transmitted daily for every activated model in response to meteorological conditions, rainfall etc);

• weather forecasts; or • advertising material.

The receiving device also includes means to over-ride control to allow the user to irrigate as desired, test the irrigation system etc. The device will also allow discontinuation of irrigation should it ever be necessary as a result of system damage or the like.

The word 'comprising' and forms of the word 'comprising' as used in this description and in the claims does not limit the invention claimed to exclude any variants or additions. Modifications and improvements to the invention will be readily apparent to those skilled in the art. Such modifications and improvements are intended to be within the scope of this invention.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method for remote management of a plurality of irrigation sites, each site having a receiving device in communication with one or more switching devices for controlling irrigation of the site, the method comprising the steps of: (a) establishing a number of soil moisture models, each site being associated with an appropriate model;

(b) for each model:

(i) making progressive estimates of soil moisture content; and

(ii) determining whether the soil moisture content has fallen below a refill point for the model; and

(c) for each model in respect of which the soil moisture content has fallen below the refill point, communicating an irrigation signal to the receiving devices of all sites associated with the model to initiate, or enable, irrigation of those sites; wherein each model is adapted to control the irrigation of any number of sites associated with the model.

2. A method according to claim 1 wherein the irrigation signal in respect of a model is transmitted both to receiving devices of sites associated with the model and to receiving devices of sites that are not associated with the model, the transmission including a model identifier interpretable by the receiving devices for determination of whether the irrigation signal is applicable to the site.

3. A method according to claim 1 or claim 2 wherein each soil moisture model is defined by:

(b) a sector identifier selected from a predetermined list of sector identifiers; and

(c) a refill point; each site being associated with a model having the appropriate soil texture identifier, sector identifier, and refill point for the site.

4. A method according to claim 3 wherein each soil moisture model is further defined by a vegetation type identifier selected from a predetermined list of vegetation type identifiers, each site being associated with a model having the appropriate soil texture identifier, sector identifier, vegetation type identifier and refill point for the site.

5. A method according to claim 3 or claim 4 wherein the estimated soil moisture content for the model is determined by a calculation that produces substantially the same result as estimating a maximum soil moisture content for the model and making adjustments for moisture loss from, and for moisture addition to, the model.

6. A method according to claim 5 wherein the soil moisture content estimates for a model are determined in dependence on an estimated root zone depth for the model, the estimated root zone depth for the model being determined in dependence on the model's soil texture identifier.

7. A method according to claim 6 wherein the estimated root zone depth for the model is determined also in dependence on the vegetation type identifier.

8. A method according to claim 6 or claim 7 wherein the estimated root zone depth for the model is determined also in dependence on the model's sector identifier.

9. A method according to any one of claims 5 to 8 wherein the maximum soil moisture content for the model is determined in dependence on the product of the estimated root zone depth for the model and an estimated soil moisture holding capacity for the model.

10. A method according to any one of claims 5 to 9 wherein the soil moisture loss for a model is estimated in dependence on meteorological data measured in respect of the model's sector.

11. A method according to claim 10 wherein the meteorological data includes solar radiation data.

12. A method according to any one of claims 5 to 11 wherein each soil moisture model is further defined by a harshness factor selected from a predetermined list of harshness factors and wherein the soil moisture loss for a model is adjusted in dependence on the harshness factor.

13. A method according to any one of claims 5 to 12 wherein the soil moisture addition for a model includes rainfall data measured in respect of the model's sector.

14. A method according to claim 13 wherein the rainfall data is, or is based on, Doppler radar data.

15. A method according to any one of claims 5 to 14 wherein the soil moisture addition for a model includes a standard amount of water assumed to be applied during irrigation.

16. A method according to claim 15 wherein the standard amount is sufficient water to raise the soil moisture content of the model to the maximum soil moisture content for the model.

17. A method according to claim 15 or claim 16 wherein following receipt by a receiving device of an irrigation signal applicable to a site, the receiving device causes its switching device or devices to irrigate for a time sufficient to add the standard amount of water to the site.

18. A method according to any one of claims 3 to 17 wherein, for each model in respect of which rain is detected or forecast in the model's sector, communicating an irrigation halt signal to the receiving devices of all sites associated with the model.

19. A distributed system for remote management of a plurality of irrigation sites, the system comprising:

(a) a receiving device in communication with one or more switching devices for controlling irrigation of each site;

(b) a host computer system having memory containing a computer program and being adapted to execute the computer program, the computer program embodying a number of soil moisture models, each site being associated with an appropriate model, wherein the logic underlying each model involves:

(i) making progressive estimates of soil moisture content; and (ii) determining whether the soil moisture content has fallen below a refill point for the model; the host computer system being adapted to communicate an irrigation signal to the receiving devices of all sites associated with the model to initiate, or enable, irrigation of those sites following the program determining that the soil moisture content of a model has fallen below the refill point for the model; wherein each model is adapted to control the irrigation of any number of sites associated with the model.

20. A distributed system according to claim 19 wherein the host computer system is adapted to transmit an irrigation signal in respect of a model both to receiving devices of sites associated with the model and to receiving devices of sites that are not associated with the model, the transmission including a model identifier interpretable by the receiving devices for determination of whether the irrigation signal is applicable to the site.

21. A distributed system according to claim 19 or claim 20 wherein each soil moisture model is defined by:

(a) a soil texture identifier selected from a predetermined list of soil texture identifiers; (b) a sector identifier selected from a predetermined list of sector identifiers; and

22. A distributed system according to claim 21 wherein each soil moisture model is further defined by a vegetation type identifier selected from a predetermined list of vegetation type identifiers, each site being associated with a model having the appropriate soil texture identifier, sector identifier, vegetation type identifier and refill point for the site.

23. A distributed system according to claim 21 or claim 22 wherein the estimated soil moisture content for the model is determined by a calculation that produces substantially the same result as estimating a maximum soil moisture content for the model and making adjustments for moisture loss from, and for moisture addition to, the model.

24. A distributed system according to claim 23 wherein the soil moisture content estimates for a model are determined in dependence on an estimated root zone depth for the model, the estimated root zone depth for the model being determined in dependence on the model's soil texture identifier.

25. A distributed system according to claim 24 wherein the estimated root zone depth for the model is determined also in dependence on the model's vegetation type identifier.

26. A distributed system according to claim 24 or claim 25 wherein the estimated root zone depth for the model is determined also in dependence on the model's sector identifier.

27. A distributed system according to any one of claims 23 to 26 wherein the maximum soil moisture content for the model is determined in dependence on the product of the estimated root zone depth for the model and an estimated soil moisture holding capacity for the model.

28. A distributed system according to any one of claims 23 to 27 wherein the soil moisture loss for a model is estimated in dependence on meteorological data measured in respect of the model's sector.

29. A distributed system according to claim 28 wherein the meteorological data includes solar radiation data.

30. A distributed system according to any one of claims 23 to 29 wherein each soil moisture model is further defined by a harshness factor selected from a predetermined list of harshness factors and wherein the soil moisture loss for a model is adjusted in dependence on the harshness factor.

31. A distributed system according to any one of claims 23 to 30 wherein the soil moisture addition for a model includes rainfall data measured in respect of the model's sector.

32. A distributed system according to claim 31 wherein the rainfall data is, or is based on, Doppler radar data.

33. A distributed system according to any one of claims 23 to 32 wherein the soil moisture addition for a model includes a standard amount of water assumed to be applied during irrigation.

34. A distributed system according to claim 33 wherein the standard amount is sufficient water to raise the soil moisture content of the model to the maximum soil moisture content for the model.

35. A distributed system according to claim 33 or claim 34 configured such that, following receipt by a receiving device of an irrigation signal applicable to a site, the receiving device causes its switching device or devices to irrigate for a time sufficient to add the standard amount of water to the site.

36. A distributed system according to any one of claims 21 to 35 configured such that, if rain is detected or forecast in a sector of a model, the host computer system communicates an irrigation halt signal to the receiving devices of all sites associated with the model.

37. A host computer system according to the host computer system of the distributed system of any one of claims 19 to 36.

38. A receiving device for communicating with one or more switching devices and being adapted to control irrigation of an irrigation site, the receiving device being adapted to receive an irrigation signal to initiate, or enable, irrigation, and to receive an irrigation halt signal to cause irrigation to cease, the receiving device having model identification means for determining whether a received signal carrying a model identifier is applicable to the receiving device.

39. A receiving device according to claim 30 wherein the model identification means is a computer executing a computer program for model identification.

40. A receiving device according to claim 30 wherein the model identification means is a dip switch or the like.

41. A receiving device according to any one of claims 38 to 40 having a soil texture identifier entry means for entering a soil texture identifier.

42. A receiving device according to any one of claims 38 to 41 having a sector identifier entry means for entering a sector identifier.

43. A receiving device according to any one of claims 38 to 42 having a refill point entry means for entering a refill point.

44. A receiving device according to any one of claims 38 to 43 having a vegetation type identifier entry means for entering a vegetation type identifier.

45. A receiving device according to any one of claims 38 to 44 having a harshness factor entry means for entering a harshness factor.

46. A receiving device according to any one of claims 38 to 45 having an irrigation system precipitation rate entry means for entering an irrigation system precipitation rate.

47. A receiving device according to any one of claims 38 to 46 wherein one or more of the identifier entry means, refill point entry means or irrigation system precipitation rate entry means is a dip switch, a series or dip switches, or the like.

48. A receiving device according to any one of claims 38 to 47 adapted to be retrofitted to an existing irrigation controller.