Irrigation controller using regression model

• US 20020010516A1
• Filed: 01/11/2001
• Published: 01/24/2002
• Est. Priority Date: 07/07/2000
• Status: Abandoned Application

• Current Assignee: Aqua Conservation Systems, Inc., John Addink
• Original Assignee: Aqua Conservation Systems, Inc., John Addink
• Inventors: Givargis, Tony, Addink, John
• Application Number:
  US09/759,788
• Publication Number:
  US 20020010516A1
• Time in Patent Office: Days
• US Class Current: 700/19
• CPC Class Codes: A01G 25/167 Control by humidity of the soil itself or of devices simulating soil or of the atmosphere; Soil humidity sensors
• CPC Class Codes: G05B 17/02 electric

Abstract

The present invention provides systems and methods in which an irrigation controller uses a regression model to estimate an evapotranspiration rate (estimated ETo), and uses the estimated ETo to affect an irrigation schedule executed by the controller. The regression model is preferably based upon a comparison of historical ETo values against corresponding historical environmental values, with the data advantageously spanning a time period of at least one month, and more preferably at least two months. Data for multiple environmental factors may also be used. The environmental factor(s) utilized may advantageously comprise one or more of temperature, solar radiation, wind speed, humidity, barometric pressure, cloud cover and soil moisture. Values relating the environmental factor(s) may enter the controller from a local sensor, a distal signal source, or both.

Claims

1. An irrigation controller comprising:

a memory that stores a regression model;

a microprocessor that applies a value for an environmental factor to the regression model to estimate an evapotranspiration rate (estimated ETo); and

a mechanism that uses the estimated ETo to affect an irrigation schedule executed by the controller.

2. The controller of claim 1 wherein the regression model is based at least in part upon a set of historical ETo values and a set of corresponding historical values for the environmental factor.

3. The controller of claim 2 wherein the set of historical ETo values spans a time period of at least two days.

4. The controller of claim 2 wherein the regression model is further based upon a second set of historical values for a second environmental factor.

5. The controller of claim 1 wherein the regression model comprises a linear regression.

6. The controller of claim 1 wherein the regression model comprises a multiple regression.

7. The controller of claim 1 wherein the regression model is based on Hargreave'"'"'s formula for determining estimated ETo.

8. The controller of claim 1 wherein the regression model is based on Thomthwaite'"'"'s formula for determining estimated ETo.

9. The controller of claim 1 wherein the environmental factor is at least one of temperature, solar radiation, wind speed, humidity, barometric pressure, cloud cover, and soil moisture.

10. The controller of claim 9 wherein the temperature is air temperature.

11. The controller of claim 9 wherein the temperature is soil temperature.

12. The controller of claim 2 wherein the environmental factor is selected from the group consisting of temperature, solar radiation, wind speed, humidity, barometric pressure, cloud cover and soil moisture.

13. An irrigation system comprising an irrigation controller according to claim 1, and a local sensor that provides a signal corresponding to the value for the environmental factor.

14. An irrigation system comprising an irrigation controller according to claim 1, and a receiver that receives from a distal source a signal corresponding to the value for the environmental factor.

15. The controller of claim 1, further comprising the mechanism using an irrigation efficiency value to at least partly affect the irrigation schedule executed by the controller.

16. The controller of claim 1, further comprising the mechanism using a crop coefficient value to at least partly affect the irrigation schedule executed by the controller.

17. A method of improving harmony in a marriage comprising installing the controller in claim 1 at a residence of a married couple.

18. A residential irrigation system having a controller according to claim 1, and having no more than 8 irrigation stations.