Sunday, October 21, 2007

Hand held, Google Earth RADAR System

A high resolution, handheld, RADAR system could be made
using modern electronics and information technology,

You could quasi-randomly modulate (Variable transmit and listen periods),
a solid state microwave oscillator (Gunn Diode)
with a digital code with good correlation properties (Gold Code),

cross-correlate the echoes received when in the listen mode
with the Gold Code, then cross-correlate the correlations
from the echoes with stored geo-patterns downloaded
from a Google-Earth like data base covering the area of operation,

compare adjacent (In time) echo returns to spot moving targets,
then present the pattern on a small, solid state, color display
that shows the Google-Earth like picture of the area,
with super-imposed moving targets.

You would not need a directional antenna,
nor high power for such a device,
but it would be necessary to sweep the device around
to build up a good correlation of
the area as one's body and other things
would block the signals and,
even though the Google-Earth like picture,
and the location of the RADAR would still be valid,
but blocked moving targets would not be detected.

Note that if a map of the area of operation is downloaded
into the system, and a set of times from the radar to fixed
targets is compared to the map, one could quickly correlate the
map with the echoes and determine where one is.

With such a device, one could move around,
and see where they were on a moving Google-Earth-like picture,
and see the moving targets about them,
perhaps even colored and shaped by the RADAR signatures
of the targets. (People, cars, tanks, trains, an incoming missile, etc.)

Note that for many situations that such a device could replace GPS.
Just like GPS, after the device determines where one is,
it would be able to compute changes in position quickly.

Note that Citizens Band transmitters have a power output if
about four watts, and this system would operate on much less power
as it would be pulsed and use modern digital communications.
A range of only a few miles should be enough to find enough
landmarks the system could use for references.


bz said...

The hand held radar would ONLY work if the user moved around.

Each 'echo' would give you a circle (actually a sphere) around the device. The origin of the echo would be somewhere on that circle.

The location of the source of the echos could be pinpointed only after observing the echos from many such devices or by observing echos from one device at several different locations(at least two different locations)

Tom Potter said...

As I indicated in my post:

"You would not need a directional antenna,nor high power for such a device, but it would be necessary to sweep the device around to build up a good correlation of the area.."

One would not have to move to "two locations" but would have to "sweep" the area so that prominent points could be detected to correlate with the Google data base.