Motion detection and alerting system

• US 6,700,528 B2
• Filed: 09/27/2002
• Issued: 03/02/2004
• Est. Priority Date: 09/27/2002
• Status: Expired due to Fees

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Williams, Christopher R., Yankielun, Norbert E.
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US10/255,763
• Publication Number:
  US 20030034912A1
• Time in Patent Office: 522 Days
• Field of Search: 342/26, 342/28, 342/99, 342/104, 342/114, 342/115, 340/962, 340/539.36, 340/601
• US Class Current: 342/28
• CPC Class Codes: G01S 13/56 for presence detection presence detection using near field arrangements G01V3/00, e.g. G01V3/08, G01V3/12; burglar, theft or intruder alarms with electrical actuation G08B13/22 - G08B13/26
• CPC Class Codes: G01S 13/60 wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed, drift angle, ground track G01S13/64 takes precedence
• CPC Class Codes: G01S 13/88 Radar or analogous systems specially adapted for specific applications electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 11/10 Logperiodic antennas H01Q11/08 takes precedence
• CPC Class Codes: H01Q 19/30 the primary active element being centre-fed and substantially straight, e.g. Yagi antenna

Abstract

A compact, autonomous motion detecting and alerting system alerts to the movement of objects of interest. Mounted on an environmentally sealed PC board are a transceiver such as a CW radar front-end, connectors, signal processors and a communications device. The system provides early warning of movement of an ice sheet or rubble field via the communication device that may be a cellular telephone. This system is mounted proximate the target surface under observation, oriented at pre-specified offset angles both laterally and in elevation. The target is illuminated and energy reflected therefrom is mixed with a portion of the transmitted signal to produce a difference frequency signal that is processed to establish existence of motion within a pre-specified velocity range. Upon verification of motion, notification is sent to a responsible authority. An autonomous or semi-autonomous power source and integral power management function may be incorporated on the same PC board.

Claims

1. A compact, inexpensive, autonomous motion detection and alerting system for detecting motion within a pre-specified velocity range, components of said system comprising:

at least one transceiver sub-assembly;

wherein said at least one transceiver sub-assembly;

propagates electromagnetic energy as a transmitted signal in a pre-specified pattern and direction to illuminate a non-smooth surface;

receives at least some energy reflected therefrom as a reflected signal; and

provides a reference signal at a pre-specified sampling rate; and

at least one signal processing sub-assembly in operable communication with said at least one transceiver sub-assembly,

wherein, by determining the difference in frequency between said reference signal and said reflected signal, said at least one processing sub-assembly establishes the existence of a pre-specified range of Doppler frequencies that may be correlated to motion having velocities within said pre-specified velocity range, and

wherein said at least one processing sub-assembly employs at least one decision algorithm to establish movement of said non-smooth surface, and wherein said at least one processing sub-assembly enables said alerting based upon a pre-specified output of said decision algorithm.

2. The system of claim 1 in which said transceiver sub-assembly comprises:

at least one radar transceiver;

at least one connector in operable communication with said at least one radar transceiver;

at least one antenna in operable communication with said at least one connector;

at least one impedance matching device in operable communication with said at least one connector and said at least one antenna; and

at least one signal mixer in operable communication with said connector,

wherein said at least one signal mixer receives signal inputs from said at least one radar transceiver and said at least one antenna via said at least one connector and outputs at least one signal product, said at least one signal product to include at least one signal at a Doppler frequency as appropriate.

3. The system of claim 2 mounted on a single printed circuit (PC) board, in which:

said at least one radar transceiver comprises a CW microwave source having an average output power between approximately 10 and 20 dBm;

said at least one connector comprises a T-connector;

said at least one impedance matching device comprises an impedance matching transformer;

said at least one antenna comprises a strip line beam antenna; and

said at least one signal mixer comprises a single-end signal mixer.

4. The system of claim 2 in which said at least one antenna is selected from the group consisting of:

a stripline antenna, a stripline beam antenna, a Yagi stripline beam antenna, a log periodic array (LPA) stripline beam antenna, a wire element beam antenna, a tubular element beam antenna, a microwave horn antenna, a microwave dish antenna, and any combination thereof.

5. The system of claim 4 in which said at least one antenna offers both forward gain of approximately at least 10 dB and antenna main lobe dimensions of approximately 60°

or less.

6. The system of claim 3 in which said processing sub-assembly comprises:

analog circuitry in operable communication with said transceiver sub-assembly,

wherein said analog circuitry conditions said signals for digital processing;

digital circuitry in operable communication with said analog circuitry;

wherein said digital circuitry employs at least one decision algorithm for determining movement of said non-smooth surface; and

a communications device in operable communication with said digital circuitry.

7. The system of claim 6 in which:

said analog circuitry comprises;

at least one first amplifier for amplifying at least one said signal product from said signal mixer;

at least one bandpass filter having an input and an output;

wherein said at least one bandpass filter passes only those Doppler frequencies that correlate to said pre-specified velocity range;

at least one second amplifier, having an input and an output, for amplifying said output of said bandpass filter; and

a Schmitt trigger for final conditioning of said output of said second amplifier;

said digital circuitry comprises;

at least one analog-to-digital (A/D) converter in operable communication with said threshold circuit;

a digital signal processor (DSP) in operable communication with said A/D converter,

wherein said DSP implements said at least one decision algorithm and a power management function; and

said communications device comprises;

at least one autodialer;

at least one cellular phone; and

at least one cellular phone antenna.

8. The system of claim 7 in which at least some of said system'"'"'s components are enclosed within a weatherproof enclosure.

9. The system of claim 7 further comprising a power source installed on said single PC board.

10. The system of claim 9 in which said power source includes at least one solar panel augmenting at least one rechargeable battery.

11. The system of claim 7, further comprising at least one mounting bracket.

12. A method for detecting and alerting to the movement of a target surface, comprising:

mounting, at a location proximate said target surface, a motion detecting and alerting system having components to include a transceiver for producing a first signal containing electromagnetic energy;

providing power to said motion detecting and alerting system;

illuminating at least part of said at least one target surface with said first signal;

receiving at least one second signal representing electromagnetic energy reflected from said target surface as a result of said illuminating;

processing said at least one second signal together with at least one reference signal provided from said transceiver,

wherein said processing produces at least one difference frequency signal representing the difference in frequency between said at least one reference signal and said at least one second signal;

establishing a value of said at least one difference frequency signal,

wherein a non-zero value indicates motion that may be of at least one pre-specified type;

processing any non-zero value difference signal by implementing at least one decision algorithm, having an input and an output, to minimize false alarms; and

using said output of said at least one decision algorithm, providing notification of any occurrence of said at least one pre-specified type of said motion.

13. The method of claim 12, in which said notification, at least in part, comprises placing a telephone call automatically.

14. The method of claim 12, in which said establishing said value of said at least one difference frequency signal further comprises introducing at least one pre-specified delay period prior to sending said notification.

15. The method of claim 12, further comprising selectively powering said components based on system demand.

16. The method of claim 12, further comprising mounting said system such that said antenna is oriented in respect to said target surface at an offset angle less than approximately 60°

both laterally and in elevation.

17. The method of claim 12, further comprising mounting said system such that said antenna is oriented in respect to said target surface with an offset angle between approximately 0°

and 30°

both laterally and in elevation.

18. The method of claim 12, further comprising using an inclinometer to achieve an accuracy of at least ±

1.0°

in orienting said system.

19. An autonomous ice sheet and rubble motion detecting and alerting system, components of said system mounted on at least one printed circuit (PC) board, said system comprising:

at least one transceiver sub-assembly;

wherein said at least one transceiver sub-assembly;

propagates electromagnetic energy as a transmitted signal in a pre-specified pattern and direction to illuminate said ice sheet and rubble;

receives at least some energy reflected therefrom as a reflected signal; and

provides a reference signal; and

at least one signal processing sub-assembly in operable communication with said at least one transceiver sub-assembly,

wherein, by comparing said propagated signal with said reflected signal, said at least one processing sub-assembly establishes the existence of a pre-specified range of Doppler frequencies that may be correlated to an expected velocity of motion representative of said ice sheet and rubble, and

wherein said at least one processing sub-assembly employs at least one decision algorithm to establish movement of said ice sheet and rubble, and wherein said at least one processing sub-assembly enables said alerting based upon a pre-specified output of said decision algorithm.

20. The system of claim 19 in which said transceiver sub-assembly incorporates a CW radar front-end.