EVIDENCE TRACKING
First Claim
1. A method for use with an electrically conductive line and with tags, the line having first and second ends and being at least twenty feet in length, the tags each having a respective identifier and disposed to receive queries at a radio frequency no greater than 1 MHz and to emit responses thereto at a radio frequency no greater than 1 MHz, the tags each mechanically affixed to a respective bag having an opening and a closure for the opening, the method comprising the steps of:
- defining a first scene of interest having a perimeter, the scene of interest having an area, the area exceeding twenty-five square feet, the perimeter extending at least twenty feet;
deploying the line starting with its first end at a first point at the perimeter, along the perimeter around the first scene of interest, and returning with its second end to the first point;
connecting the first and second ends to first apparatus operating at a radio frequency no greater than 1 MHz;
operating the first apparatus to emit a query;
operating the first apparatus to listen for a response to the query from a tag;
in the event of a response, extracting an identifier from the response, storing the identifier in the first apparatus, and transmitting a silence request with respect to the identifier;
repeating the emitting, listening, extracting, storing, and transmitting steps, thereby accumulating a list of identifiers;
making note of times at which the list changes, thereby detecting events of tags entering and leaving the first scene of interest;
after the preceding steps, removing the line;
after removing the line, defining a second scene of interest having a perimeter, the second scene of interest having an area, the area exceeding twenty-five square feet, the perimeter extending at least twenty feet;
deploying the line starting with its first end at a first point at the perimeter, along the perimeter around the second scene of interest, and returning with its second end to the first point; and
connecting the first and second ends to first apparatus operating at a radio frequency no greater than 1 MHz.
1 Assignment
0 Petitions
Accused Products
Abstract
A system uses a large loop antenna, connected with a transceiver operating below 1 MHz. The loop antenna is deployed from a spool to surround a crime scene, and may carry indicia communicating that it is a crime scene boundary. The system interrogates devices, including evidence bags and badged personnel, as they enter and leave the scene. The system can optionally log the time of salient events. A second loop antenna can log evidence bags as they enter a vehicle. The devices can be silenced by the transceiver and thus collisions can be reduced and avoided among responses from devices. The system performs “area reads” that would not be possible if higher RF frequencies were employed.
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Citations
13 Claims
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1. A method for use with an electrically conductive line and with tags, the line having first and second ends and being at least twenty feet in length, the tags each having a respective identifier and disposed to receive queries at a radio frequency no greater than 1 MHz and to emit responses thereto at a radio frequency no greater than 1 MHz, the tags each mechanically affixed to a respective bag having an opening and a closure for the opening, the method comprising the steps of:
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defining a first scene of interest having a perimeter, the scene of interest having an area, the area exceeding twenty-five square feet, the perimeter extending at least twenty feet; deploying the line starting with its first end at a first point at the perimeter, along the perimeter around the first scene of interest, and returning with its second end to the first point; connecting the first and second ends to first apparatus operating at a radio frequency no greater than 1 MHz; operating the first apparatus to emit a query; operating the first apparatus to listen for a response to the query from a tag; in the event of a response, extracting an identifier from the response, storing the identifier in the first apparatus, and transmitting a silence request with respect to the identifier; repeating the emitting, listening, extracting, storing, and transmitting steps, thereby accumulating a list of identifiers; making note of times at which the list changes, thereby detecting events of tags entering and leaving the first scene of interest; after the preceding steps, removing the line; after removing the line, defining a second scene of interest having a perimeter, the second scene of interest having an area, the area exceeding twenty-five square feet, the perimeter extending at least twenty feet; deploying the line starting with its first end at a first point at the perimeter, along the perimeter around the second scene of interest, and returning with its second end to the first point; and connecting the first and second ends to first apparatus operating at a radio frequency no greater than 1 MHz. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An electrically conductive line comprising a tape bearing printed indicia visible from a distance, the indicia comprising the words “
- CRIME SCENE”
, the line being at least twenty feet in length.
- CRIME SCENE”
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13. Apparatus comprising a spool, the spool having wound thereon an electrically conductive line comprising a tape bearing printed indicia visible from a distance, the indicia comprising the words “
- CRIME SCENE”
, the line being at least twenty feet in length.
- CRIME SCENE”
Specification