Transceiver system and method utilizing nanosecond pulses

• US 6,812,884 B2
• Filed: 03/12/2003
• Issued: 11/02/2004
• Est. Priority Date: 03/12/2003
• Status: Active Grant

• Current Assignee: Zebra Technologies Corporation
• Original Assignee: Multispectral Solutions Incorporated (Zebra Technologies Corporation)
• Inventors: Richley, Edward A., Fontana, Robert J.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US10/385,658
• Publication Number:
  US 20040178947A1
• Time in Patent Office: 601 Days
• Field of Search: 342/21, 342/27, 342/28, 342/42-51, 342/82, 342/89-103, 342/118, 342/134-145, 342/175, 342/192-197
• US Class Current: 342/125
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26

Abstract

A transceiver for short-pulse radar applications is disclosed in which a shift register or the like is used to collect return signal information in a manner to reduce the number of transmit pulses needed and to increase the speed of determining the positions of multiple scattering objects. In addition, there is also disclosed cooperating transceivers arranged as transponders similarly utilizing shift registers or other pulse sampling techniques to accurately determine the linear distance between them based on relationships between or among propagation time, measured offsets, and internal clock skews. Corresponding methods are also disclosed.

Claims

1. A transceiver to ascertain distance of an object, said transceiver comprising:

a generator to produce a trigger signal,

a transmitter that transmits a nanosecond pulse in response to said trigger signal,

a receiver including a pulse detector to detect return signals produced by reflections of said nanosecond pulse,

a shift register that samples return signals during multiple time-shifted intervals following an occurrence of said trigger signal, and

a controller that obtains data samples from respective cells of said shift register and that ascertains a distance of at least one object associated with one of said samples based on a number of intervals following the occurrence of said trigger signal.

2. The transceiver of claim 1, wherein said generator comprises a system clock that produces said trigger signal in the form of a periodic clock signal, said transceiver further including a high-frequency clock synchronized with said system clock to define said intervals of said shift register during a period of said system clock.

3. The transceiver of claim 2, wherein said shift register records a data sample in a first cell thereof upon an initial occurrence of said nanosecond pulse, said shift register further including an inhibitor that halts sampling by said shift resister to enable said controller to obtain said data samples.

4. The transceiver of claim 2, wherein said receiver includes a receive antenna that receives said return signals and an adjustable amplifier disposed between the receive antenna and said pulse detector to adjust an amplification level of said return signals.

5. The transceiver of claim 2, including a second shift register that samples time-delayed return signals and said controller obtains data samples from said second shift register whereby to provide increased resolution of distances or times of receipt of said return signals.

6. A transceiver utilizing nanosecond pulses to ascertain object distance, said transceiver comprising:

a system clock to produce a periodic clock signal,

a transmitter that periodically transmits nanosecond pulses according to said clock signal,

a receiver including a tunnel diode detector that detects object return signals produced by echoes of said nanosecond pulses,

a register that samples said object return signals at discrete time intervals between successive periods of said clock signal, and

a controller that obtains data samples from said register to ascertain object distances according to a number of discrete time intervals associated with said data samples.

7. The transceiver of claim 6, further comprising a high-speed clock synchronized with said system clock in order to effect shifting of said register.

8. The transceiver of claim 7, wherein said controller utilizes a time base of said high-speed clock and a number of shifts of a data sample in said register to ascertain an object distance associated with said data sample.

9. A method of determining distance of multiple scattered objects comprising:

producing a trigger signal,

transmitting an RF pulse in response to said trigger signal,

detecting return signals produced by reflections of said RF pulse from said objects,

sampling return signals during respective ones of multiple time intervals following an initial occurrence of said trigger signal thereby to produce respective data samples associated with respective ones of said objects, and

ascertaining distance of respective ones of said objects based on an associated number of time intervals following said initial occurrence.

10. The method of claim 9 wherein said trigger signal comprises a periodic clock signal and said sampling step occurs during intervals of said clock signal defined by a high-frequency clock.

11. The method of claim 10 further including, during said sampling step, recording a data sample upon initial occurrence of said RF pulse, and said ascertaining step occurs at a sampling interval defined by the initial transmission.

12. The method of claim 10 further including, prior to said detecting step, amplifying return signals of said RF pulse.

13. The method of claim 10, wherein said sampling step includes sampling a delayed representation of said return signals and said ascertaining step utilizes said sampled data and said delayed representation to determine distance.

14. A method of ascertaining distance of an object comprising:

providing a system clock to produce a periodic clock signal,

transmitting a nanosecond pulse according to said clock signal,

detecting an object return signal produced by an echo of said nanosecond pulse,

registering an occurrence of an object return signal during at least one of multiple discrete time intervals within a period of said clock signal, and

ascertaining distance by obtaining data samples produced by said registering step thereby to ascertain an object distance associated with the interval of occurrence of said return signal.

15. The method of claim 14, further including the step of providing a high-speed clock synchronized with said system clock to effect said registering during said discrete time intervals.

16. The method of claim 15, wherein said ascertaining step utilizes a time base of said high-speed clock and a number of shifts during said registering to ascertain an object distance associated with said return signal.

17. A system to determine a distance between participating objects having cooperating transceivers, said system comprising:

first and second transceivers respectively associated with the participating objects;

each transceiver including a system clock to produce a local clock signal, a transmitter that transmits a nanosecond pulse according to the clock signals, a local receiver including a detector that detects a nanosecond pulse transmitted by the other transceiver, a local shift register that samples presence of a nanosecond pulse during respective timing intervals defined by a high-speed clock, said high-speed clock being synchronized with the local system clock; and

the second transceiver having a controller that accesses the local shift register thereof to ascertain a first offset measurement of a first packet sent by the first transceiver;

the first transceiver having an associated controller that accesses the local shift register thereof to ascertain a second offset measurement of a second packet sent in response to receipt of the first packet by the second transceiver, said second packet including information indicative of the first offset measurement, said associated controller ascertaining inter-object distance based on a relationship among said offset measurements, clock skew, and propagation time.

18. A system to determine distance between two objects, said system comprising:

first and second transceivers respectively associated with the objects;

each transceiver including a transmitter that transmits an RF pulse, a detector that detects an RF pulse transmitted by the other transceiver, a register that registers a time instance of receipt of an incoming RF pulse; and

a second controller of the second transceiver that accesses the register thereof to ascertain a first offset measurement of a first packet sent by the first transceiver; and

a first controller of the first transceiver that accesses the register thereof to ascertain a second offset measurement of a second packet sent by the second transceiver in response to the first packet, said second packet including information indicative of the first offset measurement, said fist controller determining inter-object distance based on said offset measurements, clock skew information, and propagation time.

19. The system of claim 18, wherein a trigger signal effects emission of said RF pulse and said offset measurement is made in relation to said trigger signal.

20. The system of claim 18, wherein each transceiver includes a system clock to periodically effect transmission of said RF pulse and a high-speed clock synchronized with said system clock to effect step-wise sampling by said register of a signal including an incoming RF pulse.

21. The system of claim 20, wherein said RF pulse comprises a nanosecond pulse.

22. The system of claim 21, wherein said detector comprises a tunnel diode detector.

23. The system of claim 20, wherein said register comprises a shift register and said system further includes a matrix having rows indicative of data samples of said shift register observed during an interval defined by said system clock, respective rows of said matrix comprising information indicative of the first offset measurement.

24. The system of claim 23, wherein rows of said matrix include data samples representative of an identification code comprising a pattern of ones and zeroes.

25. The system of claim 20, wherein said register comprises a matrix having rows indicative of data samples observed during respective intervals of said system clock wherein respective rows of said matrix represent a unit of information sent by one transceiver to the other transceiver.

26. The system of claim 18, wherein said register includes a matrix having rows indicative of data samples observed during an interval following transmission of said RF pulse.

27. A transceiver system to ascertain a distance between participating objects, said system comprising:

first and second transceivers respectively co-located with said participating objects, each transceiver having an associated pulse transmitter to transmit a nanosecond pulse, an associated detector to detect a nanosecond pulse, and an associated local shift register that samples an incoming nanosecond pulse sent by the other transceiver during successive shift intervals thereof; and

a controller associated with at least one transceiver that utilizes predetermined circuit delays and positions of sampled data in said shift register to ascertain time of flight of a pulse between said objects whereby to ascertain said distance between participating objects according to said time of flight.

28. The system of claim 27, further including a matrix that records in respective rows thereof contents of said shift register obtained during respective sampling interval.

29. The system of claim 28, wherein data sampled during a given sampling interval of each row of said matrix indicates transmitted information.

30. The system of claim 29, wherein said transmitted information comprises an identification code.

31. A method of determining distance between participating objects, said method comprising:

providing first and second transceivers respectively associated with the participating objects;

at the first transceiver, transmitting a nanosecond pulse according to a local clock signal;

at the second transceiver, detecting the nanosecond pulse transmitted by the first transceiver, producing data samples by sampling a presence of the transmitted nanosecond pulse during respective timing intervals defined by a high-speed clock synchronized with the local clock signal, and accessing said data samples to ascertain a first offset measurement relative to a system clock signal of a first packet sent by a first transceiver; and

at the first transceiver, producing data samples by sampling a presence of the transmitted return data and accessing said data samples to ascertain a second offset measurement relative to a system clock signal of a second packet sent in response to receipt of the first packet by the second transceiver, said second packet including information indicative of the first offset measurement, and ascertaining inter-object distance based on a relationship among said offset measurements, clock skew, and propagation time.

32. A method of determining distance between two objects based on propagation time of an RF pulse traveling between said objects, said method comprising:

providing first and second transceivers respectively associated with the objects, each transceiver having an associated system clock and clock skew;

transmitting the RF pulse from a first transceiver, detecting the RF pulse at the second transceiver, and registering at the second transceiver a time instance of receipt of the RF pulse relative to a system clock, and accessing a first offset measurement of a first packet sent by the first transceiver according to said time instance; and

at said first transceiver, registering relative to a system clock receipt of a second packet sent by the second transceiver in response to the first packet thereby to ascertain a second offset measurement, said second packet including information indicative of the first offset measurement, and determining inter-object distance based on said offset measurements, clock skews, and propagation time.

33. The method of claim 32, wherein the system clock of one transceiver periodically effects transmission of said RF pulse and each transceiver includes a high-speed clock synchronized with a system clock thereof to effect step-wise sampling of a signal including an incoming RF pulse during said registering step of each transceiver.

34. The method of claim 33, wherein said RF pulse comprises a nanosecond pulse.

35. The method of claim 34, wherein said detector comprises a tunnel diode detector.

36. The method of claim 33, further including the step of providing a matrix having rows indicative of data samples observed during an interval defined by said system clock, said data samples representing information indicative of the first offset measurement.

37. The method of claim 33, wherein said register includes a matrix having rows indicative of data samples observed during an interval following transmission of said RF pulse.

38. The method of claim 33, wherein rows of said matrix include data samples representative of an identification code comprising a pattern of ones and zeroes.

39. The method of claim 33, wherein said registering includes providing a matrix having rows indicative of data samples observed during an interval defined by said system clock wherein rows of said matrix include data samples representative of information sent by one transceiver to the other transceiver.

40. A method of ascertaining distance or propagation time of a nanosecond pulse between participating objects, said method comprising:

providing first and second transceivers respectively co-located with the participating objects, each transceiver having an associated pulse transmitter to transmit a nanosecond pulse, an associated detector to detect a nanosecond pulse, and an associated local shift register that samples an incoming signal to detect a nanosecond pulse sent by the other transceiver during successive shift intervals thereof; and

utilizing predetermined circuit delays and position of sampled data in said shift register to ascertain time of flight of a pulse whereby to ascertain distance between said objects.

41. The method of claim 40, further including recording in respective rows of a matrix the contents of said shift register obtained during respective sampling intervals.

42. The method of claim 41, wherein data sampled during a given sampling interval of each row of said matrix indicates transmitted information.

43. The method of claim 42, wherein said transmitted information comprises an identification code.