Distance measurement for wireless building automation devices

• US 20060049976A1
• Filed: 09/09/2004
• Published: 03/09/2006
• Est. Priority Date: 09/09/2004
• Status: Active Grant

• Current Assignee: Siemens Industry Incorporated (Siemens AG)
• Original Assignee: Siemens Building Technologies Incorporated (Siemens AG)
• Inventors: McFarland, Norman R.
• Granted Patent: US 7,408,839 B2
• Time in Patent Office: Days
• US Class Current: 342/118
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G01S 5/30 Determining absolute distances from a plurality of spaced points of known location

Abstract

In a building environment, a distance associated with a building automation device is determined as a function of an inserted time delay between a wireless transmission of a signal and wireless reception of another signal. For example, a two-way communication is provided with a time delay inserted before responding to a received transmission. By using two-way transmissions, the building automation devices may be free of clock synchronization. Acoustic signals may be used in a building environment to determine a distance. The building automation device may also use radio frequency information for communicating with other devices. Communication between devices allows a controller to coordinate the determination of distances associated with different devices within a network, such as through transmission of a test signal and assigning distance measurement operations to devices that receive the test signal with sufficient strength or other characteristics.

Claims

1. A method for determining a distance for a building automation device, the method comprising:

(a) wirelessly transmitting a first signal from the building automation device within a building;

(b) wirelessly receiving a second signal at the building automation device within the building;

(c) inserting a set time delay between (a) and (b); and

(d) determining a distance associated with the building automation device as a function of the set time delay and time-of-flight for the first and second signals.

2. The method of claim 1 wherein (b) is performed after (a), wherein (c) is performed by a remote building automation device within the building.

3. The method of claim 1 wherein (a) is performed after (b), wherein (c) is performed by the building automation device.

4. The method of claim 1 wherein (d) comprises determining the distance with a processor of the building automation device.

5. The method of claim 1 wherein (a) comprise transmitting a first acoustic signal and wherein (b) comprises receiving a second acoustic signal.

6. The method of claim 1 wherein (a) comprises transmitting a first radio frequency signal and wherein (b) comprises receiving a second radio frequency signal.

7. The method of claim 1 wherein (c) comprises:

(c1) identifying a first portion of the first signal; and

(c2) waiting for the set time period after receiving the portion of the first signal;

wherein (d) comprises;

(d1) identifying a second portion of the second signal; and

(d2) determining the time-of-flight from transmission of the first portion to reception of the second portion minus the set time period.

8. The method of claim 1 wherein (d) comprises determining the distance between the building automation device and a remote building automation device, the building automation device and the remote building automation device being free of clock synchronization.

9. The method of claim 1 wherein (b) comprises receiving the second signal as a first to arrive signal.

10. The method of claim 5 further comprising:

(e) configuring a network of devices including the building automation device for distance determination with radio frequency signals;

(f) generating a test acoustic signal from a first device of the network of devices;

(g) determining which devices of the network adequately received the test acoustic signal; and

(h) performing (a), (b) and (c) for each of the devices of the network determined in (g) relative to the first device.

11. A system for determining a distance for building automation components, the system comprising:

a first building automation device having a first wireless transmitter, a first wireless receiver and a first processor;

a second building automation device having a second wireless transmitter, a second wireless receiver and a second processor;

wherein the first wireless transmitter is operable to transmit a first signal, the second wireless receiver is operable to receive the first signal, the second wireless transmitter is operable to transmit a second signal in response to reception of the first signal, the second processor is operable to insert a set time delay between reception of the first signal and transmission of the second signal, the first wireless receiver operable to receive the second signal, and the first processor operable to determine a distance between the first and second building automation devices as a function of the set time delay and time from transmission of the first signal to reception of the second signal.

12. The system of claim 11 wherein the first and second transmitters comprise speakers and the first and second receivers comprise microphones.

13. The system of claim 12 wherein the first transmitter and first receiver comprise a same first acoustic transducer, and the second transmitter and second receiver comprises a same second acoustic transducer.

14. The system of claim 11 wherein the first transmitter and first receiver comprise a first radio frequency transceiver, and the second transmitter and second receiver comprises a second radio frequency transceiver.

15. The system of claim 11 wherein the second processor is operable to identify a first portion of the first signal and insert the set time delay from reception of the first portion, and wherein the first processor is operable to identify a second portion of the second signal and determining the time-of-flight from transmission of the first portion to reception of the second portion minus the set time delay.

16. The system of claim 11 wherein the first and second building automation devices are free of clock synchronization with each other.

17. The system of claim 11 wherein the first and second processors are operable to identify the second and first signals, respectively, as the first to arrive signals.

18. The system of claim 12 further comprising:

first and second radio frequency transceivers connected with the first and second building automation devices, respectively;

wherein the first and second processors are responsive to radio frequency data in determining the distance with the microphones and speakers.

19. A method for determining a distance for a building automation device, the method comprising:

(a) transmitting a first acoustic signal from a first speaker of a first building automation device within a building;

(b) receiving the first acoustic signal with a first microphone of a second building automation device within the building; and

(c) determining a distance from the first speaker to the first microphone as a function of the acoustic signal.

20. The method of claim 19 further comprising:

(d) transmitting a second acoustic signal from a second speaker, the second speaker collocated with the first microphone; and

(e) receiving the second acoustic signal with a second microphone, the second microphone collocated with the first speaker;

wherein (d) is performed in response to (b); and

wherein (c) comprises determining the distance as a function of time-of-flight of the first and second acoustic signals.

21. The method of claim 20 wherein (d) is performed in response to (b) after a set time delay, and wherein (c) comprises determining the distance as a function of time from (a) until (e) and the set time delay.

22. The method of claim 19 wherein (a) comprises transmitting an ultrasound signal.

23. The method of claim 19 wherein (b) comprises accepting a first to arrive signal and rejecting echoes.

24. The method of claim 19 further comprising:

(d) coordinating (a) and (b) with wireless radio frequency transmissions.

25. The method of claim 24 wherein (d) comprises assigning a group of building automation devices to determine respective distances to a first building automation device having one of the microphone and speaker.

26. A building automation device for determining distance after placement within a building, the building automation device comprising:

a sensor, an actuator or combinations thereof operable for control of an environment of the building;

an acoustic transceiver;

a radio frequency transceiver; and

a processor operable to control the acoustic transceiver for distance determination operation in response to control signals from the radio frequency transceiver, the processor operable to process data of the sensor, actuator or combinations thereof.

27. The building automation device of claim 26 wherein the processor is operable to cause the acoustic transceiver to transmit a first ultrasound signal and is operable to determine a distance from the building automation device to another device as a function of a received second ultrasound signal.

28. The building automation device of claim 27 wherein the processor is operable to cause the radio frequency transceiver to transmit the distance and the data of the sensor, actuator or combinations thereof.

29. A system for determining distances in a wireless building automation network, the system comprising:

a plurality of spaced apart building automation devices; and

a controller operable to wirelessly communication with the plurality of spaced apart building automation devices;

wherein the controller is operable to cause a first one of the plurality of spaced apart building automation devices transmit a test ranging signal, assign one or more of the plurality of spaced apart building automation devices to the first one of the plurality of spaced apart building automation devices as a function of reception by the one or more of the plurality of spaced apart building automation devices of the test ranging signal, and cause distances from the first one to the assigned one or more of the plurality of spaced apart building automation devices to be determined.