Micro-radar, micro-radar sensor nodes, networks and systems

• US 8,264,401 B1
• Filed: 04/22/2012
• Issued: 09/11/2012
• Est. Priority Date: 12/29/2011
• Status: Active Grant

• Current Assignee: Sensys Networks Inc. (Tagmaster AB)
• Original Assignee: Sensys Networks Inc. (Tagmaster AB)
• Inventors: Kavaler, Robert
• Primary Examiner(s): Brainard, Timothy A
• Application Number:
  US13/452,892
• Time in Patent Office: 142 Days
• Field of Search: 342118-146
• US Class Current: 342/128
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/14 wherein a voltage or current pulse is initiated and terminated in accordance respectively with the pulse transmission and echo reception
• CPC Class Codes: G01S 13/20 whereby multiple time-around echoes are used or eliminated
• CPC Class Codes: G01S 13/26 wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
• CPC Class Codes: G01S 13/28 with time compression of received pulses
• 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: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: G01S 7/288 Coherent receivers
• CPC Class Codes: G01S 7/4004 of parts of a radar system

Abstract

A micro-radar is disclosed that is operated based upon two Digital to Analog Converter (DAC) outputs that control its internal timing and Intermediate Frequency (IF) signal frequency. Calibration and temperature compensation is done through estimating the duty cycle of the transmit signal and possibly the reception signal that stimulate a pulse generator to create the transmit pulse and the reception pulse and adjusting one or both DAC outputs. Sensor processors, wireless sensor nodes and wireline sensor nodes are disclosed for operating the micro-radar. An integrated circuit is disclosed implementing all or portions of the micro-radar. Access points, servers as well as systems that include but are not limited to a traffic monitoring system, a traffic control system, a parking management system and/or a production management system are also disclosed.

Claims

1. An apparatus, comprising:

a micro-radar adapted to generate an antenna output of less than or equal to 10 milli-Watt (mW) through an antenna to an object and receive a Radio Frequency (RF) reflection off of said object, and adapted to respond to a first Digital to Analog Converter (DAC) output and a second DAC output, comprising;

a timing generator adapted to generate a transmit signal with a first edge in response to said first DAC output and a system clock; and

said timing generator adapted to generate a reception signal with a second edge in response to said second DAC and said system clock, where said second edge has a delay from said first edge that sweeps through a short delay to a long delay over a time interval;

said micro-radar generates a transmit RF burst in response to said first edge of said transmit signal for delivery to said antenna to generate said antenna output in response to said transmit pulse;

said micro-radar mixes a received RF reflection of said RF reflection and said transmit RF burst, in response to said second edge of said reception signal, to generate an Intermediate Frequency (IF) signal with a peak amplitude at a sweep delay Tm for a distance T0 of said object from said antenna; and

a frequency of said IF signal is one over a compression ratio multiplied by a carrier frequency of said antenna output, where said compression ratio is about one million.

2. The apparatus of claim 1, wherein said timing generator, comprises at least one of:

a transmit control generator adapted to receive said first DAC output and a first exponentially changing signal to generate a duty cycle of said transmit signal to stimulate a duty cycle estimator to generate said duty cycle signal; and

/or

a reception control generator adapted to receive said second DAC output, a second exponentially changing signal and a clock signal to generate said reception signal.

3. The apparatus of claim 2, wherein said micro-radar further comprises at least one of:

a first Analog to Digital Converter (ADC) coupling of said IF signal to generate an IF sample approximating said peak amplitude at said sweep delay; and

/or

a second Analog to Digital Converter (ADC) coupling of a duty cycle signal based upon said transmit signal to generate a duty cycle estimate that indicates said compression ratio.

4. The apparatus of claim 2, wherein said transmit control generator comprises a first analog sum of said first exponentially changing signal and said first DAC output to generate a first analog signal triggering a first sharp threshold device to generate said transmit signal with said duty cycle;

and/or

said reception control generator comprises a second analog sum of said second DAC output, said second exponentially changing signal and said clock signal to generate a second analog signal triggering a second sharp threshold device to generate said reception signal.

5. The apparatus of claim 4, wherein at least one of said first sharp threshold device and said second sharp threshold device includes a logic gate and/or a comparator and/or a level shifter.

6. The apparatus of claim 1, wherein said compression ratio is one million to within twenty percent.

7. The apparatus of claim 1, wherein said micro-radar is implemented as an integrated circuit.

8. The apparatus of claim 1, wherein said object includes at least one of a person, a bicycle, a motorcycle, an automobile, a truck, a bus, a trailer and an aircraft.

9. The apparatus of claim 1, wherein said object is a surface of a filling of a chamber.

10. The apparatus of claim 1, further comprising at least one of:

a wireless sensor node and/or a wireline sensor node, each configured to operate an instance of said micro-radar to send a report regarding said sweep delay for said object; and

/or

a processor configured to receive and to respond to said report by generating an estimate of said distance of said object from said micro-radar; and

/or

an access point configured to wirelessly communicate with said micro-radar via said radio transceiver to send a version said report to said processor; and

/or

a server configured to communicate said version of said report from said micro-radar to said processor.

11. The apparatus of claim 10, wherein said wireless sensor node and/or said wireline sensor node further comprises a sensor processor configured to operate said micro-radar by control of said first DAC output and said second DAC output.

12. The apparatus of claim 11, wherein at least one of said processor, said access point, said server and/or said sensor processor includes at least one instance of at least one of a finite state machine and a computer accessibly coupled to a memory containing a program system comprised of program steps configured to instruct said computer.

13. The apparatus of claim 12, wherein said program system comprises at least one of the program steps of:

operating said micro-radar based upon control of said first DAC output and/or said second DAC output to control said compression ratio and said IF signal;

receiving an ADC reading based upon said IF signal and/or said sweep delay for said object;

generating said report based upon said ADC reading and/or said sweep delay;

responding to said report by sending said version of said report to said processor;

second responding to said report and/or said version to generate said distance of said object from said micro-radar;

third responding to said distance of said object from said micro-radar by updating at least one of a traffic monitoring system, a traffic control system, a parking management system, and/or a production management system;

second operating said micro-radar based upon said first DAC output and/or said second DAC output to insure said sweep delay Tm corresponds to a specific distance T0 of said object;

third operating said micro-radar based upon said first DAC output and/or said second DAC output to generate said IF signal dominated by a background noise to create a background noise estimate;

using said background noise estimate to adjust a detect threshold of said object; and

/or

detecting said object based upon said ADC reading and said detect threshold.

14. The apparatus of claim 13, wherein the program step of operating said micro-radar further comprises at least one of the program steps of

controlling said first DAC output and said second DAC output to generate said sweep delay for said object;

setting said second DAC output to generate said IF signal for said background noise to dominate; and

calibrating said first DAC output to establish said IF frequency.

15. The apparatus of claim 13, further comprising:

at least one of said traffic monitoring system, said traffic control system, said parking management system, and/or said production management system is adapted to communicate with at least one of said micro-radar, said wireless sensor node, said wireline sensor node, said processor, said access point and/or said server.

16. The apparatus of claim 1, wherein said compression ratio is one million to within one thousand.

17. The apparatus of claim 1, wherein said antenna output is compliant with an Ultra-Wide Band (UWB) signal protocol.

18. The apparatus of claim 1, wherein said IF signal has a frequency of between 6 Kilo (K) Hertz (Hz) and 7 KHz.

19. A method, comprising the step of:

operating a micro-radar transmitting an antenna output through an antenna to an object and receiving a Radio Frequency (RF) reflection off of said object, further comprising the steps of;

responding to a first Digital to Analog Converter (DAC) output to generate a transmit signal with a first edge and a duty cycle;

responding to a second DAC output to generate a reception signal with a second edge at a delay from said transmit first edge, where said delay sweeps through a short delay to a long delay over a time interval;

operating a RF transceiver/mixer (RFTM) to generate a transmit RF burst in response to said first edge of said transmit signal;

generating a reception pulse in response to said second edge of said reception signal; and

operating said RFTM to mix said transmit RF burst and a received RF reflection in response to said reception pulse to generate an Intermediate Frequency (IF) signal with a peak amplitude at a sweep delay Tm for a distance T0 of said object from said antenna.

20. The method of claim 19, wherein the step of operating said micro-radar further comprises at least one of the steps of:

calibrating said first DAC output based upon a duty cycle of said transmit pulse;

calibrating said second DAC output based upon a compression ratio of said time interval divided by a difference between said long delay subtracted from said short delay;

setting said second DAC output beyond said long delay to generate a background noise estimate from an Analog to Digital Converter (ADC) reading of said IF signal;

processing said ADC reading to estimate said sweep delay Tm and/or said distance T0;

processing said ADC reading based upon said background noise estimate to estimate said sweep delay Tm and/or said distance T0.