Method and device for estimation of the transmission characteristics of a radio frequency system

• US 8,466,826 B2
• Filed: 05/15/2012
• Issued: 06/18/2013
• Est. Priority Date: 05/11/2007
• Status: Active Grant

• Current Assignee: Sky ID Incorporated
• Original Assignee: Sky ID Incorporated
• Inventors: Charland, Shawn
• Primary Examiner(s): Brainard, Timothy A
• Application Number:
  US13/471,808
• Publication Number:
  US 20120225619A1
• Time in Patent Office: 399 Days
• Field of Search: 342 13- 20
• US Class Current: 342/14
• CPC Class Codes: F41H 13/0075 the high-energy beam being a radiofrequency beam
• CPC Class Codes: H04B 17/327 Received signal code power [RSCP]
• CPC Class Codes: H04B 17/3913 Predictive models, e.g. based on neural network models
• CPC Class Codes: H04K 2203/24 for communication related to weapons
• CPC Class Codes: H04K 3/42 characterized by the control of the jamming frequency or wavelength
• CPC Class Codes: H04K 3/43 characterized by the control of the jamming power, signal-to-noise ratio or geographic coverage area
• CPC Class Codes: H04K 3/92 related to allowing or preventing remote control
• CPC Class Codes: H04K 3/94 related to allowing or preventing testing or assessing

Abstract

A device and method for estimation of the transmission characteristics of a Radio Frequency system are provided. The device and method calculate a predicted receive power at a given location using a propagation and scenario model. Then a measured receive power at the given location is used to determine a correction value equal to the difference between the calculated and measured receive powers. The correction value and the propagation model are then used with a heuristic method to refine estimates of propagation and scenario parameters. The refined parameter set is used to produce a refined prediction of receive power, which is used to create a refined correction factor. The refined correction factor is used to determine predicted receive powers at a plurality of locations.

Claims

1. A method comprising:

using an RF transmission characteristic estimation device to perform steps of;

calculating for a first location a predicted received power level of an RF signal generated by a RF system transmitter;

determining a correction value based on the predicted received power level and a measured received power level of the RF signal at the first location; and

calculating for a second location a predicted received power level of the RF signal using a correction value based on the correction value at the first location.

2. The method of claim 1, further comprising:

calculating for the first location a plurality of predicted received power levels of the RF signal generated by the RF system transmitter, inclusive of calculating the first predicted received power level for the first location, wherein each one of the plurality of predicted received power levels corresponds to a respective frequency component of the RF signal;

determining a plurality of correction values based on the plurality of predicted received power levels and a plurality of measured received power levels of the RF signal measured at the first location, inclusive of determining the first correction value based on the first predicted received power level and the first measured received power level; and

calculating a plurality of predicted received power levels for the second location using a plurality of correction values based on the correction values at the first location, inclusive of calculating the first predicted received power level for the second location using the first correction value.

3. The method of claim 1, wherein the RF signal generated by the RF system transmitter comprises an electronic countermeasures (ECM) signal.

4. The method of claim 1, further comprising:

predicting a probabilistic ability of the RF signal generated by the RF system transmitter to prevent triggering of a potential threat device at the second location based on the predicted received power level of the RF signal at the second location and potential threat device characteristics.

5. The method of claim 4, wherein the potential threat device characteristics comprise a predicted response of the potential threat device to the predicted received power level of the RF signal at the second location.

6. The method of claim 5 wherein the predicted response of the potential threat device to the predicted received power level of the RF signal comprises a predicted response of the potential threat device to a given jamming-to-signal ratio.

7. The method of claim 1, wherein determining the correction value comprises calculating the correction value according to:

Δ

P1=ECM<sub>meas—

at—

first—

location</sub>−

ECM<sub>unref—

at—

first—

location</sub>

where Δ

P1 is the correction value, ECM<sub>meas—

at—

first—

location</sub> is the actual received power level of the RF signal at the first location, and ECM<sub>unref—

at—

first—

location</sub> is the predicted received power level of the RF signal at the first location, wherein

calculating the predicted received RF signal at the second location comprises;

calculating an unrefined predicted received power level of the RF signal at the second location; and

calculating the predicted received power level of the RF signal at the second location'"'"'according to;

ECM<sub>ref—

at—

second—

location</sub>=ECM<sub>unref—

at—

second—

location</sub>+Δ

P1

where ECM<sub>ref—

at—

second—

location</sub> is the predicted received power level of the RF signal at the second location, and ECM<sub>unref—

at—

second—

location</sub> is the unrefined predicted received power level of the RF signal at the second location.

8. The method of claim 1 further comprising:

generating a mismatch cost function based on a comparison of the predicted received power level of the RF signal at the first location and the measured received power level of the RF signal at the first location; and

indicating a fault/anomaly if the mismatch cost function exceeds a threshold value.

9. The method of claim 1 further comprising:

calculating a respective predicted received power level of the RF signal generated by the RF system transmitter for each location of a plurality of locations in an area using a correction value based on the correction value at the first location; and

for each location predicting probabilistic ability of the RF signal generated by the RF system transmitter to prevent triggering of a potential threat device at the location based on the respective predicted received power level of the RF signal at the location and the potential threat device characteristics.

10. The method of claim 9, wherein the potential threat device characteristics comprise a predicted response of the potential threat device to the respective predicted received power level of the RF signal for each location of the plurality of locations in the area.

11. The method of claim 10 further comprising calculating an effective range of the RF system transmitter by determining a boundary at which the probabilistic ability of the RF signal generated by the RF system transmitter to prevent triggering of the potential threat device is at a threshold.

12. The method of claim 11 further comprising displaying the protective range of the RF system transmitter.

13. The method of claim 11, wherein calculating each respective predicted received power level of the RF signal comprises:

calculating a predicted received power level of the RF signal for each location for each one of a population of N scenario parameter sets to generate N predicted received power levels for each location,

wherein for each location the probabilistic ability of the RF signal generated by the RF system transmitter to prevent triggering of the potential threat device at the location is derived from the probabilistic effect of the N predicted received power levels of the RF signal for the location.

14. The method of claim 8 wherein generating the mismatch cost function is based on best-case and/or worst-case predicted received power levels of the RF signal at the first location,

wherein the worst-case and/or best case predicted received power level of the RF signal at the first location is derived from N predicted received power levels of the RF signal at the first location calculated using a population of N scenario parameter sets, and

wherein the best-case predicted received power level of the RF signal at the first location is derived from the population of N predicted received power levels of the RF signal at the first location.

15. The method of claim 13, further comprising, for each location:

determining an average predicted received power level of the RF signal from the N predicted received power levels of the RF signal; and

determining standard deviation of the N predicted received power levels of the RF signal.

16. The method of claim 13, further comprising:

predicting a worst-case and/or best-case protection range of the RF system transmitter;

predicting a nominal protection range of the RF system transmitter; and

displaying the worst-case and/or best-case and/or predicted ranges of the RF system transmitter.

17. The method of claim 1 wherein calculating a predicted received power level of the RF signal comprises calculating a predicted received power level of the RF signal using a propagation and scenario model.

18. The method of claim 17 further comprising adapting model parameters to substantially fit the predicted received power level of the RF signal at the first location to the measured received power level of the RF signal at the first location.

19. The method of claim 18, wherein adapting the parameters of the model comprises using a heuristic method to substantially fit the predicted received power level of the RF signal at the first location to the measured received power level of the RF signal at the first location.

20. The method of claim 19, wherein the heuristic method comprises at least one of:

a genetic algorithm, an evolutionary algorithm, Tabu search, simulated annealing, and a memetic algorithm.

21. The method of claim 18, wherein:

the RF signal comprises at least one pilot signal; and

the measured received power level of the RF signal comprises the measured receive power level of the at least one pilot signal transmitted by the RF system transmitter.

22. The method of claim 21, further comprising:

determining a set of scenario model parameters that, for each one of the at least one pilot signal frequencies, substantially fit the predicted received power level of the RF signal at the first location to the measured received power level of the RF signal at the first location, wherein the determination of the set of scenario model parameters is based at least in part on an adjustment of at least one of amplitude, phase, and center frequency of at least one of the at least one pilot signal.

23. The method of claim 22, wherein the adjustment of at least one of amplitude, phase, and center frequency of the at least one pilot signal is based on signalling from a device physically remote from the RF system transmitter.

24. The method of claim 18, further comprising estimating uncertainty associated with at least one parameter of the propagation and scenario model based on discrepancies between the measured received power level of the RF signal at the first location and one or more statistical properties of a population of predicted received power levels of the RF signal at the first location, wherein the statistical properties of predicted received power levels of the RF signal at the first location is derived from a population of N predicted received power levels of the RF signal at the first location calculated using N scenario parameter sets.

25. The method of claim 21, wherein only a single pilot signal is used at any moment and a center frequency of the single pilot signal is varied across a plurality of frequencies, wherein the model parameters are adapted to:

a) substantially fit the predicted received power level of the RF signal at the first location to the measured received power level of the RF signal at the first location for each frequency of the plurality of pilot signal frequencies; and

b) estimate uncertainty in at least one model parameter based on discrepancies between the measured received power level of the RF signal at the first location and the predicted received power level of the RF signal at the first location, where the predicted received power level of the RF signal is calculated using the adapted set of model parameters.

26. A device comprising:

a processor configured to;

calculate for a first location a predicted received power level of an RF signal generated by an RF system transmitter;

determine a correction value based on the predicted received power level and a measured received power level of the RF signal at the first location; and

calculate for a second location a predicted received power level of the RF signal using a correction value based on the correction value determined for the first location.

27. The device of claim 26, further comprising:

receive circuitry configured to receive a signal from another device indicating the measured received power level of the RF signal at the first location.

28. The device of claim 26, wherein the RF signal comprises an electronic countermeasures (ECM) signal generated by an ECM system transmitter.

29. The device of claim 26, wherein the processor predicts probabilistic ability of the RF signal at the second location to prevent triggering of a potential threat device at the second location based on the predicted received power level of the RF signal at the second location and potential receiver characteristics.

30. The device of claim 29, wherein the potential receiver characteristics comprise a predicted response of the potential receiver to the predicted received power level of the RF signal at the second location.

31. The device of claim 30 wherein the predicted response of the potential receiver to the predicted received power level of the RF signal comprises a predicted response of the potential receiver to a given jamming-to-signal ratio.

32. The device of claim 29, further comprising a user interface having:

a display that displays the probabilistic ability of the RF signal to prevent triggering of a potential threat device at the second location; and

input controls that allow a user to control the display and edit parameters of a propagation and scenario model that the processor uses to calculate the predicted received power level of the RF signal.

33. The device of claim 26, wherein the processor determines a correction value according to:

Δ

P1=ECM<sub>meas—

at—

first—

location</sub>−

ECM<sub>unref—

at—

first—

location</sub>)

where Δ

P1 is the correction value, ECM<sub>meas—

at—

first—

location</sub> is the actual received power level of the RF signal at the first location, and ECM<sub>unref—

at—

first—

location</sub> is the predicted received power level of the RF signal at the first location, wherein

the processor is configured to;

calculate an unrefined predicted received power level of the RF signal at the second location; and

calculate the predicted received power level of the RF signal at the second location according to;

ECM<sub>ref—

at—

second—

location</sub>=ECM<sub>unref—

at—

second—

location</sub>+Δ

P1

where ECM<sub>ref—

at—

second—

location</sub> is the predicted received power level of the RF signal at the second location, and ECM<sub>unref—

at—

second—

location</sub> is the unrefined predicted received power level of the RF signal at the second location.

34. The device of claim 26, wherein the processor is configured to:

generate a spectrum mismatch cost function based on a comparison of the predicted RF system spectrum at the first location and the measured RF system spectrum at the first location; and

indicate a fault/anomaly if the mismatch cost function exceeds a threshold value.

35. The device of claim 29 wherein the processor is configured to:

calculate a respective predicted received power level of the RF signal for each location of a plurality of locations in an area using a correction value based on the correction value determined for the first location; and

for each location;

predict probabilistic ability of the RF signal at the location to prevent triggering of a potential threat device at the location based on the respective predicted received power level of the RF signal at the location and the potential threat device characteristics.

36. The device of claim 35, wherein the potential threat device characteristics comprise a predicted response of the potential threat device to the respective predicted received power level of the RF signal for each location of the plurality of locations in the area.

37. The device of claim 36, wherein the processor determines an effective range threshold of the RF system by determining a boundary at which the probabilistic ability of the RF signal generated by the RF signal transmitter to prevent triggering of a potential threat device.

38. The device of claim 37, further comprising a display, wherein the display displays the effective range threshold of the RF system.

39. The device of claim 36, wherein the processor uses a propagation and scenario model to calculate the predicted received power level of the RF signal at each location.

40. The device of claim 39, wherein:

the RF signal comprises at least one pilot signal; and

the processor is configured to adapt parameters of the propagation and scenario model to;

a) substantially fit the predicted received power level of the RF signal at the first location to the measured received power level of the RF signal at the first location for each of the pilot signal frequencies; and

b) estimate uncertainty in at least one of the parameters of the model based on discrepancies between the measured received power level of the RF signal at the first location and the predicted received power level of the RF signal at the first location predicted using the adapted set of model parameters.

41. The device of claim 40, further comprising communication circuitry, wherein the device communicates, using its communication circuitry, with the RF system transmitter to adjust the at least one pilot signal generated by the RF system transmitter.

42. The device of claim 41, wherein the adjustment of the at least one pilot signal comprises adjustment of at least one of amplitude, phase, and center frequency of at least one of the at least one pilot signal, and wherein the processor is configured to adapt the parameters of the model to substantially fit the predicted received power level of the RF signal at the first location to the measured received power level of the RF signal at the first location for each of the pilot signal frequencies.

43. The device of claim 39, wherein the processor is configured to predict uncertainty associated with at least one parameter of the propagation and scenario model based on discrepancies between the predicted received power level of the RF signal at the first location and the measured received power level of the RF signal at the first location, wherein the predicted received power level of the RF signal at the first location comprises one or more statistical properties of a population of N predicted received power levels of the RF signal at the first location calculated using N sets of scenario parameters.

44. The device of claim 39, wherein the processor is further configured to:

calculate a predicted received power level of the RF signal for each location N times using a different set of propagation and scenario parameters for each of the N times; and

determine one or more statistical properties of the population of N predicted received power levels of the RF signal for each location, wherein the processor predicts the probabilistic ability of the RF signal to prevent triggering of a potential threat device at each location using one or more statistical properties of the population of N predicted received power levels of the RF signal at the location.

45. The device of claim 44, further comprising a display, wherein:

the processor is configured to;

determine a worst-case predicted received power level of the RF signal at each location from the N predicted received power levels of the RF signal at each location;

determine a best-case predicted received power level of the RF signal at each location from the N predicted received power levels of the RF signal at each location;

predict a worst-case and/or best-case predicted RF system effective range threshold; and

calculates a nominal predicted RF system effective range threshold; and

the display is configured to;

show the nominal predicted RF system effective range threshold and/or the worst-case RF system effective range threshold, and/or the best-case RF system effective range threshold.

46. The device of claim 39 wherein the processor is configured to adapt parameters of the propagation and scenario model to substantially fit the predicted received power level of the RF signal at the first location to the measured received power level of the RF signal at the first location.