Harmonic block technique for computing space-time solutions for communication system network nodes

• US 7,876,266 B2
• Filed: 01/16/2009
• Issued: 01/25/2011
• Est. Priority Date: 12/07/2006
• Status: Active Grant

• Current Assignee: Digimarc Corporation
• Original Assignee: ZuluTime LLC
• Inventors: Rhoads, Geoffrey
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Mull; Fred H
• Application Number:
  US12/355,436
• Publication Number:
  US 20100045531A1
• Time in Patent Office: 739 Days
• Field of Search: 342463-465, 342/387, 342/357.14, 342/357.28, 342/357.29, 342/357.49, 342/357.42
• US Class Current: 342/463
• CPC Class Codes: G01S 5/18 using ultrasonic, sonic, or infrasonic waves
• CPC Class Codes: G01S 5/26 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/28 takes precedence

Abstract

A method solving for unknown location values and clock rate values of one or more nodes of a network of nodes communicating with one another entails associating multiple transmitting nodes and receiving nodes that produce, respectively, ping transmit events and ping receive events by receiving and associating receive count stamps to the ping transmit events. Ping event values corresponding to ping events relating to associated ones of the ping transmit events and the ping receive events are generated and accumulated. Solutions for transmit and receive node clock rate values and node location values relating to the transmit and receive ping events at arbitrary times within a harmonic block time interval are generated from the grouped, accumulated ping event values. The generated solutions for one of the associated multiple nodes are a function of the ping transmit events and ping receive events produced by the others of the associated multiple nodes.

Claims

1. A method of solving for unknown location values and clock rate values of one or more nodes of a network of nodes communicating with one another, comprising:

associating multiple nodes including multiple transmitting nodes and multiple receiving nodes that operate with, respectively, a priori asynchronous node transmit clocks and node receive clocks, the transmitting nodes producing ping transmit events and the receiving nodes producing ping receive events by receiving and associating receive count stamps to the ping transmit events;

for each transmitting node of the multiple nodes, the ping transmit events taking place at transmission times corresponding to a transmit clock count produced in response to operation of the node transmit clock, and, for each receiving node of the multiple nodes, the ping receive events taking place at receive times corresponding to a receive clock count produced in response to operation of the node receive clock;

generating ping event values corresponding to ping events relating to associated ones of the ping transmit events and the ping receive events;

accumulating the ping event values produced by the multiple nodes;

grouping the accumulated ping event values corresponding to multiple ones of the ping events that include ping events associated with multiple different pairs of nodes of the network and that occur within a harmonic block time interval; and

generating from the grouped, accumulated ping event values solutions for transmit and receive node clock rate values and node location values relating to the transmit and receive events at arbitrary times within the harmonic block time interval, the solutions for node clock rate and node location values of one of the associated multiple nodes being a function of the ping transmit events and ping receive events produced by the others of the associated multiple nodes.

2. The method of claim 1, in which the harmonic block time interval has predetermined time boundaries, and further comprising performing, for the harmonic block time interval, node location interpolation weighting between successive solutions for node location values relative to the predetermined time boundaries.

3. The method of claim 1, in which the harmonic block time interval has predetermined time boundaries, and further comprising representing the node location of each of the multiple nodes at a transmit time or a receive time as a linear combination of the solutions for node location values at a predetermined time within the predetermined time boundaries of the harmonic block time interval.

4. The method of claim 1, in which the harmonic block time interval has predetermined time boundaries, and further comprising performing, for the harmonic block time interval, clock rate interpolation weighting between successive solutions for transmit and receive node clock rate values relative to the predetermined time boundaries.

5. The method of claim 1, in which the harmonic block time interval has predetermined time boundaries, and further comprising representing the transmit and receive node clock rates of the multiple nodes at a transmit time or a receive time as a linear combination of the solutions for the transmit and receive node clock rate values at a predetermined time within the predetermined time boundaries of the harmonic block time interval.

6. The method of claim 1, in which the nodes of the network include a set of the transmitting nodes and a set of the receiving nodes and multiple ones in the set of transmitting nodes are members of the set of receiving nodes.

7. The method of claim 1, in which the nodes of the network include a set of the transmitting nodes and a set of the receiving nodes and at least one in the set of transmitting nodes is not a member of the set of receiving nodes.

8. The method of claim 1, in which the accumulating of ping event values takes place in one of the transmitting nodes of the network and is transmitted to other ones of the multiple nodes of the network.

9. The method of claim 1, in which two of the multiple nodes are at different locations separated by a distance and include one of the transmitting nodes and one of the receiving nodes, and the grouped, accumulated ping event values correspond to a change in the distance separating the two nodes and changes in the transmit and receive clock rates, and in which movement of each of the two nodes causes changes in their respective node locations and corresponding changes in the distance separating the node locations.

10. The method of claim 1, further comprising associating with transmit count stamps the ping transmit events produced by the transmitting nodes, and in which the ping event values include differential count stamp values corresponding to differences between the receive count stamps and the associated transmit count stamps.

11. The method of claim 1, further comprising grouping the accumulated ping event values corresponding to multiple ones of the ping events that occur within multiple harmonic block time intervals such that some of the ping event values occur within multiple harmonic block time intervals.

12. A method of solving for unknown location values and clock rate values of one or more nodes of a network of nodes communicating with one another, comprising:

associating multiple nodes including multiple transmitting nodes and multiple receiving nodes that operate with, respectively, a priori asynchronous node transmit clocks and node receive clocks, the associated multiple nodes over time being formed in different groups of transmitting and receiving nodes, and the transmitting nodes producing ping transmit events and the receiving nodes producing ping receive events by receiving and associating receive count stamps to the ping transmit events;

for each transmitting node of the multiple nodes, the ping transmit events taking place at transmission times corresponding to a transmit clock count produced in response to operation of the node transmit clock, and, for each receiving node of the multiple nodes, the ping receive events taking place at receive times corresponding to a receive clock count produced in response to operation of the node receive clock;

generating ping event values corresponding to ping events relating to associated ones of the ping transmit events and the ping receive events;

accumulating the ping event values produced by the multiple nodes;

grouping the accumulated ping event values corresponding to multiple ones of the ping events that occur within multiple harmonic block time intervals such that the ping event values occurring within the multiple harmonic block time intervals are produced by the different groups of the transmitting and receiving nodes, and for each of the multiple harmonic block time intervals, the grouped, accumulated ping event values corresponding to ping events associated with multiple different pairs of nodes of the network and that occur within the harmonic block time interval; and

generating from the grouped, accumulated ping event values solutions for transmit and receive node clock rate values and node location values relating to the transmit and receive events at arbitrary times within each of the multiple harmonic block time intervals.

13. The method of claim 12, in which over time there are different numbers of associated multiple nodes forming the different groups of transmitting and receiving nodes.