System and process for locating sources of radiation

• US 3,980,948 A
• Filed: 06/17/1974
• Issued: 09/14/1976
• Est. Priority Date: 06/17/1974
• Status: Expired due to Term

• Current Assignee: George A. Olive
• Original Assignee: George A. Olive
• Inventors: Olive, George A.
• Primary Examiner(s): Rolinec, R. V.
• Assistant Examiner(s): Tokar, Michael J.
• Application Number:
  US05/480,106
• Time in Patent Office: 820 Days
• Field of Search: 324/83 R, 324/83 D, 343/113 R
• US Class Current: 324/76.82
• CPC Class Codes: G01R 25/00 Arrangements for measuring phase angle between a voltage and a current or between voltages or currents
• CPC Class Codes: G01S 5/04 Position of source determined by a plurality of spaced direction-finders

Abstract

A vehicle location system is provided for determining the coordinate location of a vehicle through radio transmission radiation from the vehicle and the system includes a plurality of receiver sites at known coordinate locations each having antenna-coupler means providing first and second signals whose phase difference is approximately linearly related to the azimuth angle of the receiver signal from the radiation source. The first and second signals are processed at each receiver site to translate the frequency of the signals to a lower frequency and to remove the common frequency variations therefrom. Thereafter, the signals are passed through a phase detector which provides a binary output expression which is linearly related to the phase difference between the first and second signals. The binary expressions from each of the respective receiver sites are then processed through an electronic data processing means which is programed to determine the coordinates of the radiation source from the plurality of the binary expressions.

Claims

1. Signal processing apparatus for processing first and second input signals differing in phase and having common frequency variations to remove the frequency variations for subsequent improved phase measurements comprising:

a first mixing device having the first input signal as its first input;

signal generating means providing a signal as the first output of the signal processing apparatus and the second input to the first mixing device; and

a second mixing device having its first input the difference output from the first mixer and its second input the second input signal to provide a second difference output of the signal processing device in which the frequency variations are removed and which differs from the first output only by the initial phase difference.

2. A phase detector for processing first and second input signals differing in phase and providing a numeric output linearly related to the phase difference comprising:

first gate generating means having the first and second input signals as its inputs and providing a first gating signal of duration indicative of the phase difference of the first and seond input signals;

first counter means responsive to the presence of the first gate signal to provide a numeric count linearly related to the phase difference between the first and second input signals; and

monitoring means responsive to the continued presence of the first and second input signals at or above a usable value to provide a monitoring signal to continue the detector operation and responsive to the occurrence of the first or second input signals below a usable value to restart the phase detector sequence.

3. A phase detector for processing first and second input signals differing in phase and providing a numeric output linearly related to the phase difference comprising:

first gate generating means having the first and second input signals as its inputs and providing a first gating signal of duration indicative of the phase difference of the first and second input signals;

first counter means responsive to the presence of the first gating signal to provide a numeric count linearly related to the phase difference between the first and second input signals;

delay means delaying the second input signal a predetermined phase shift;

third gate generating means having the first input signal and second delayed input signal as its inputs and providing a third gating signal of duration indicative of the phase difference of the first and second delayed input signals;

second counter means responsive to the presence of the third gate signal to provide a numeric count linearly related to the phase difference between the first and second delayed inputs;

counter offset means for correcting the count from the second counter means induced by the delay means;

means for detecting when the first and second input signals are at or approaching a coincidence condition and providing a fourth gating signal upon the occurrence of a coincidence condition; and

counter gate means responsive to the presence or absence of the fourth gating signal to select the count in either the first or second counter means as the phase detector output depending upon the occurrence of a coincidence condition.