Cover letter

0060-EX-ML-2009 Text Documents

ImSAR LLC

2009-05-20ELS_98377

                                                                    May 20, 2009
                       Form 422 File Number: 0414-EX-PL-2008, modification request
Federal Communications Commission
Office of Engineering and Technology
Experimental Licensing Branch
445 12th St., S.W.
Room 7-A322
Washington, DC 20554

To Whom it May Concern,

On behalf of ImSAR LLC I would like to apply for a modification of Experimental
License Call Sign WE2XVR to further the development of a low power radar system. I
would like to increase the peak power up to 8W for certain bands, add a location near
Simi Valley CA, and add a new band centered at 1320MHz. The increased power is to
increase the usable range of the radar by several thousand feet. The request for a band of
160MHz centered around 1320 MHz is for foliage penetrating radar. This fits cleanly
within the radiolocation bands running from 1240 MHz to 1400 MHz and will have a
power spectral density of

The radar will be operated on an occasional basis of a few times per month for roughly
an hour each time it is used. The end user of these experimental systems will be
predominantly the US Department of Defense.

This request is comparable to similar systems that have been granted an STA1 and an
Experimental Radio Service License2. We have operated up to this point under STA
0130-EX-ST-2008, and more recently using experimental license call sign WE2XVR.

I hope the attached document has sufficient information to enable a favorable approval of
an experimental license.


Sincerely,
Adam Robertson
NanoSAR Program Manager
510 W 90 S
Salem UT 84653
801-762-7263
adamr@imsar.com




1
    Refer to STA file number S-2353-EX-96
2
    Refer to Experimental Radio Service file number 0302-EX-PL-2004


Purpose of radio operation:

ImSARs LLC has technology that is able to track moving targets, image the surface of
the earth, create digital elevation maps, assist in search and rescue operations, and detect
small changes in a scene, such as the movement of a vehicle. The US Navy, Army and
Air Force have expressed interest in this technology. The size, weight, power, and cost of
this Nano sized Synthetic Aperture Radar system (NanoSAR) is an order of magnitude
less than similar systems. The radical change is weight and power consumptions enables
tactical use of the radar, which in turn gives surveillance capabilities to small sets of
soldiers that were previously unavailable. With the new surveillance capabilities,
dangerous and life threatening situations can be further reduced.

Similar radar systems, such as Linx SAR weighs 85 lbs and transmit 300W of power.
ImSAR’s radar system weighs 2 lbs and transmits less than 1W of power. ImSAR
requests a license in order to complete product testing and begin customer
demonstrations.

ImSAR will use this experimental license to performed tests from a small aircraft flying
under 2km in elevation. The transmit and receive antennas are nominally pointed toward
the earth. Reflected signals are collected and processed to create images of the ground.
The resolution of the imagery is directly proportional to the bandwidth of the signal
transmitted. In order to obtain resolutions as small as 0.3 m, a transmit bandwidth of 500
MHz is desired. Transmission is linear frequency modulated continuous wave with the
frequency being swept from the minimum to the maximum frequency 1000 times per
second. Because the transmission power is under 1W and the frequency sweeps very
rapid, the average power at a given frequency is extremely low.

Transmissions will be generally performed in remote areas over very limited time
intervals of roughly an hour at a time, a few times per month.

Operation Location and Height:

NanoSAR will be operated from a small aircraft at a height between 0m and 5000m. The
transmit signal is directed perpendicular to the line of site and towards the ground using a
simple patch antenna array with a beam width approximately 45°in elevation and 10°
along the track of the aircraft. The peak of the antenna pattern has a 45° incident angle to
the ground. The return signal is received by an identical receive antenna co-located with
the transmit antenna.

Data collections will occur primarily over rural areas of northern Utah to test the
functionality and demonstrate the utility of the NanoSAR as a tool for both commercial
and military applications. Sites of interest to be imaged will be terrains of interest to
potential customers, including urban and rural scenes. Site at Boardman OR, Arlington


OR, China Lake CA, Yuma AZ, and Whidbey Island WA are also areas for testing or
potential testing of NanoSAR.




                                            Sla
                                                nt
                                             17 Ran
                                           (52 30 ft ge
          660 ft Elevation




                                              4m
                                                   )
             (200 m)




                                                                        Targets at ~800 ft
                                                                             (242m)




                                         45°                               27°
                                                                swath

                              660 ft                              940 ft
                             (200 m)                             (285 m)
                                        1600 ft
                                       (485 m)

Description of the Transmit Signal:


The transmit signal is from 10 to 10.5 GHz. Most transmissions will be further
constrained to a small bandwidth of 150 MHz centered at 10.25 Hz. The signal is
continuous and modulated only by frequency. The frequency is ramped from the bottom
of the bandwidth to the top of the bandwidth at a 1kHz rate. The received signal is mixed
with the transmitted signal in a homodyne fashion. Frequency is controlled with a highly
stable PLL and 25 MHz crystal with 25 ppm stability. The frequency ramp is controlled
with a direct digital synthesizer capable of over 60 dB ACPR. The final power amplifier
is a linear MMIC based amplifier with excellent linearity. The highest power spectral
density we anticipate is -40 dBW/Hz (75 MHz bandwidth).

We have equipment in house to measure out of band spurious signals and we regularly
measure our transmission signals to minimize harmonics and spurious signals.

Time Period of Operation

We have submitted form 1494 for NanoSAR. We anticipate the 1494 to take several
months for approval. Until that is complete, we would like to continue development. We
anticipate doing tests a few times per month, with each test typically lasting under 1 hour.


A Record of non-interference
ImSAR’s NanoSAR has logged nearly 20 hours of unmanned flight and easily more than
twice that in manned flight operating this system so far. To date we have observed no
detectable interference with other systems including communication equipment, active
military radar systems, commercial aircraft, or unmanned aircraft systems. NanoSAR has
been found to be tolerant of interference from these systems, up to and including
interference from large directional antennas and high power military radars.



Document Created: 2009-05-20 19:24:27
Document Modified: 2009-05-20 19:24:27

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