Electronic tracking and ranging system

• US 7,711,477 B2
• Filed: 05/29/2008
• Issued: 05/04/2010
• Est. Priority Date: 02/06/2004
• Status: Expired due to Fees

• Current Assignee: Kent Pearce, Teryl Pratt
• Original Assignee: Kent Pearce, Teryl Pratt
• Inventors: Pratt, Teryl, Pearce, Kent
• Primary Examiner(s): Camby; Richard M.
• Application Number:
  US12/129,464
• Publication Number:
  US 20080224855A1
• Time in Patent Office: 705 Days
• Field of Search: 701/207, 701/200, 375/140, 375/146, 375/147, 375/226, 375/371, 375/376, 340/573.1, 340/573.4, 340/539.13, 340/825.49
• US Class Current: 701/207
• CPC Class Codes: G01S 13/84 for distance determination by phase measurement

Abstract

An electronic tracked and ranging system is disclosed. Electronic tracked and ranging system applies interferometer principles to determine ranging distance from a monitor unit 10 to a tracked unit 12. In particular, the system transmits a monitor direct sequence spread spectrum (MDSSS) 52 from a monitor unit 10 to a tracked unit 12. Afterwards, tracked unit 12 transmits a tracked direct sequence spread spectrum (TDSSS) 56. Finally, monitor unit 10 receives TDSSS 56, performs a comparison to a reference MDSSS 52 locks signals between MDSSS 52 and TDSSS 56 and outputs distance between monitor unit 10 and tracked unit 12 using several phase comparisons. Multiple frequencies within MDSSS 52 are phase detected so as to increase accuracy of monitor unit 10 ranging distance to tracked unit 12.

Claims

1. An electronic system for locating an object comprising:

a monitoring unit;

a tracked unit placed on said object receiving a monitor digital spread spectrum signal (MDSSS) from said monitoring unit and transmits a tracked digital spread spectrum signal (TDSSS) to said monitoring unit; and

a first phase detector placed on said monitor unit to compare a first frequency component of said tracked digital spread spectrum signal to a monitor first frequency component creating a first phase difference utilized for a coarse accuracy determination of said object ranging distance to said monitor unit.

2. An electronic system as recited in claim 1, further comprising:

a second phase detector included within said monitor unit that compares a tracking second frequency component of said TDSSS with a monitor second frequency component to create a second phase difference; and

,

a first detector phase error output determines number of repeated frequency periods of said second frequency component of TDSSS for a medium accuracy determination of range relative to said monitor unit of said object range.

3. An electronic system as recited in claim 2, further comprising:

a third phase detector comparing a third frequency of said TDSSS with a monitor third frequency component to create a third phase difference; and

an output of second phase detector determines number of repeated frequency cycles of said tracked third frequency of said TDSSS for fine accuracy determination. of range relative to monitor unit of said object.

4. An electronic system as recited in claim 1, wherein said first frequency of said TDSSS is a repetition rate of said tracked pseudo-random noise sequence and said first monitor frequency component is a repetition rate of said monitor pseudo-random noise sequence.

5. An electronic system as recited in claim 1, wherein said second frequency component of said TDSSS is chipping frequency of said tracked pseudo-random sequence and said second frequency component of said MDSSS is a chipping frequency of said tracked pseudo-random sequence.

6. An electronic system as recited in claim 1, wherein said third frequency component of said TDSSS is a carrier frequency and said third frequency component of said MDSSS is a carrier frequency.

7. An electronic system as recited in claim 1, wherein said monitor unit comprises a first monitor antenna disposed on said monitor unit and a second monitor antenna disposed on said monitor unit, which said first monitor antenna is cross-polarized relative to said second monitor antenna for measuring said object range and relative angle from said monitor unit.

8. An electronic system as recited in claim 1, wherein said second frequency component of said TDSSS is a pseudo-random noise sequence input into a first shift register circuit and a second shift register circuit, creating said first phase difference between said first frequency component of TDSSS and said second frequency component of said MDSSS.

9. An electronic system as recited in claim 1, wherein said tracked unit receives a monitor carrier frequency from said monitor unit, wherein said tracked unit includes a phase lock loop that locks said MDSSS with said TDSSS.

10. An electronic system as recited in claim 1, wherein said monitor unit further comprises a monitor compass which displays location of said tracked unit within several concentric rings to provide a visual display for a user of said ranging distance between said monitor unit and said tracked unit.

11. An electronic system as recited in claim 1, wherein said monitor unit further comprises a monitor compass which displays location of said tracked unit and a user selects one zone from several concentric rings of coverage from said monitor unit to said tracked unit.

12. An electronic system for locating an object comprising:

a monitoring unit;

a tracked unit placed on said object receiving a monitor digital spread spectrum signal (MDSSS) from said monitoring unit and transmits a tracked digital spread spectrum signal (TDSSS) to said monitoring unit;

a first phase detector placed on said monitor unit to compare a first frequency component of said tracked digital spread spectrum signal to a monitor first frequency component creating a first phase difference utilized for a coarse accuracy determination of said object distance ranging relative to said monitor unit;

a second phase detector included within said monitor unit that compares a second frequency component of said tracked digital spread spectrum signal with a monitor second frequency component to create a second phase difference;

a first detector phase error output determines number of repeated frequency periods of said second frequency component for a medium accuracy determination of range relative to monitor unit of said object range;

wherein said first frequency component of said TDSSS is a repetition rate of said tracked pseudo-random noise sequence; and

,

wherein said second frequency component of said TDSSS is chipping frequency of said tracked pseudo-random (PN) sequence.

13. An electronic system as recited in claim 12, further comprising:

a third phase detector comparing a third frequency of said TDSSS with a monitor third reference signal to create a third phase difference; and

,

an output of second phase detector determines number of repeated frequency cycles of said third frequency component of said TDSSS for fine accuracy determination of distance ranging between said monitor unit and said object including said tracked unit.

14. An electronic system as recited in claim 12, wherein said third frequency component of said TDSSS is a carrier frequency and said third frequency component of said MDSSS is a carrier frequency.

15. An electronic system as recited in claim 12, wherein said monitor unit comprises a first monitor antenna disposed on said monitor unit and a second monitor antenna disposed on said monitor unit, which said first monitor antenna is cross-polarized relative to said second monitor antenna for measuring said object range and relative angle from said monitor unit.

16. An electronic system as recited in claim 12, wherein said second frequency component of said TDSSS is a pseudo-random noise sequence input into a first shift register circuit, creating said first phase difference between said first frequency component of said TDSSS and said monitor pseudo-random noise sequence.

17. An electronic system as recited in claim 12, wherein said monitor unit further comprises a monitor compass which displays location of said tracked unit and a user selects one zone from several concentric rings of coverage to monitor said tracked unit.

18. A method for detecting the range of an object comprising:

placing a tracked unit on said object;

transmitting a monitor digital spread spectrum signal (MDSSS) from a monitoring unit;

receiving said MDSSS at said tracked unit;

transmitting from said tracked unit a tracked digital spread spectrum signal (TDSSS) to said monitoring unit;

comparing a first frequency component of said TDSSS to a first frequency component of said MDSSS within a first phase detector; and

,

outputting a first phase shift for course accuracy determination of said object range relative to said monitor unit.

19. The method of claim 18, further comprising the steps of:

comparing a second frequency of said TDSSS to a second reference signal of said MDSSS within a second phase detector;

outputting a second phase shift;

determining the number of repeated frequency periods of said second frequency of said TDSSS.