| 66 -- RFI - Night Vision Test Set Calibration Radiometer Sought |
| Program Summary |
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| Description |
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General Information
| Document Type: |
Presolicitation Notice |
| Solicitation Number: |
N68335-08-RFI-0098 |
| Posted Date: |
Mar 06, 2008 |
| Original Response Date: |
Apr 05, 2008 |
| Current Response Date: |
Apr 05, 2008 |
| Original Archive Date: |
Apr 20, 2008 |
| Current Archive Date: |
Apr 20, 2008 |
| Classification Code: |
66 -- Instruments & laboratory equipment |
| Naics Code: |
334515 -- Instrument Manufacturing for Measuring and Testing Electricity and Electrical Signals |
Contracting Office Address
Department of the Navy, Naval Air Systems Command, Naval Air Warfare Center Aircraft Division Lakehurst, Contracts Department Hwy. 547 Attn:B562-3C, Lakehurst, NJ, 08733-5083, UNITED STATES
Description
This is a Request for Information (RFI). There is currently no solicitation package available. The Naval Air Warfare Center Aircraft Division Lakehurst is requesting information regarding hardware that is commercially available and that can be adapted or customized to support the calibration of night vision goggle test sets. The desired device will be radiometer-based and will replace the radiometers currently being used to calibrate the light level output of the Navy?s night vision goggle test sets. The radiometers now being used are approaching the end of their lifetime, and are no longer sufficient to calibrate the test sets to the accuracy desired. It is anticipated that a multi-year indefinite delivery, indefinite quantity (IDIQ) contract would be placed with a smaller initial order followed by larger orders for approximately 35 units total. The Naval Air Warfare Center Aircraft Division Lakehurst will assess overall interest and responses to this request for information in order to determine the potential for a small business set aside.
This radiometer is needed to measure the radiance of monochromatic light exiting the ports of two models of night vision goggle test sets. The light irradiating the reticle in the output port is generated by an LED inside the test set at the given wavelength. This radiometer must match the field of view requirements and fit the light emitting apertures of the test sets so that the full radiance measurement angle (FOV) of the radiometer is over-filled.
The radiometer will be calibrated on a regular calibration interval by the Navy Primary Standards Lab (NPSL) at the wavelengths of 690nm and 820nm in radiance mode in the units of Watts per centimeter squared per steradian (W/cm2/sr). This will be done by comparing the radiometer with a NIST calibrated radiometer standard using an integrating sphere source illuminated by the LED model used in the test set.
There is also a requirement to calibrate the night vision goggle test sets photopically in luminance mode, so the radiometer must also include a removable photopic filter to measure the luminance of the light emitted by the test sets in the units of foot Lamberts. The field of view requirement and the requirement to fit the light emitting apertures of the test set is the same in photopic mode as it is for the radiance mode.
The radiometer must have high sensitivity to perform calibrations at very low radiance and luminance levels.
Due to these custom fitment, optical, sensitivity, and uncertainty requirements, it is likely that a current design will have to be modified so that it is a good match for our specific electrical and optical requirements.
The Navy is interested in receiving information about what is available that could meet these requirements or a plan to modify existing hardware to meet the custom specifications. A plan for satisfying this RFI might involve taking existing hardware and combining it with commercially available optical and electrical components, or it might involve taking an existing radiometer or detector and developing optics that can mate up to the radiometer so that the combination of components will meet the night vision radiometer requirements.
Detailed Technical Specifications:
1.1 Power requirements
The radiometer standard shall meet the power requirements as indicated in MIL-PRF-28800F, section 3.5.1.12. The radiometer can either use AC voltage at a level of 10A RMS or less or be powered by an included internal or external DC source as specified by MIL-PRF-28800F.
1.2 Environmental requirements
The radiometer standard shall meet the environmental requirements as indicated in MIL-PRF-28800F for Class 3 equipment with the deviations specified in section 2.2.1.
1.2.1 Temperature and humidity requirements
The radiometer standard shall remain within specified calibration uncertainties at the conditions below:
Temperature (C) Relative Humidity (%)
Operating 20 to 25.5 20 to 70
Non-operating 0 to 40 Not controlled
1.3 Transit case requirements
The equipment shall be fitted with an included hard transit case which has provisions for the stowage of the radiometer and all accessories.
1.4 EMC and safety requirements
The equipment shall conform to ElectroMagnetic Compatibility (EMC) and safety requirements as indicated in MIL-PRF-28800F.
1.5 Radiance and luminance readout requirements
The radiometer must include either a meter attached to the detector head to read the output of the detector directly or a DC voltage output that can be read with a standard Agilent 34401A DMM or equivalent.
If a meter is included that displays the output in the units of radiance (W/cm2/sr) or luminance (fL), the meter must have the capability to be calibrated by NPSL on a periodic basis (for example, by including the capability for storing new calibration factors into the meter's EPROM).
1.6 Calibration interval requirements
The radiometer shall have a 95% or greater probability of remaining within tolerance for all requirements at the end of a 12 month period. This corresponds to a coverage factor of k=2.
1.7 Performance requirements
1.7.1 Radiance level requirements
Wavelength = 820nm, High Level: 3.0 x 10-9 W/cm2/sr
Wavelength = 820nm, Low Level: 2.5 x 10-10 W/cm2/sr
Wavelength = 690nm, High Level: 1.0 x 10-9 W/cm2/sr
Wavelength = 690nm, Low Level: 5.0 x 10-11 W/cm2/sr
These 4 power levels (2 power levels at each wavelength) correspond to the nominal radiance level outputs of the light source of the test sets used in the field. Uncertainty specifications listed below must apply to these light levels and wavelengths.
1.7.2 True radiance mode operation
Radiance versus distance error = 0.3% or less while the full radiance measurement angle (FOV) of the radiometer is over-filled
Definition: The critical distance is where the full radiance measurement angle (field of view of the radiometer matches the size of the source seen from the radiometer. The radiometer field of view is over-filled when the distance between the radiometer and the source is at this critical distance or closer.
For a radiance mode radiometer, light sensitivity is independent of the source radiometer distance while the radiometer field of view is over-filled. Experimentally, the reading of the radiance or luminance of a source over a range of distances at which the radiometer field of view is over-filled should be constant. Non-radiance mode operation can lead to large uncertainties in calibration due to the distance dependence of the calibration.
1.7.3 Luminance level requirement
Luminance = 1 foot-Lambert (fL)
As with the radiance requirements listed above, this value corresponds to the nominal luminance level that will be measured by the radiometer in the field. Uncertainty specifications listed in section 1.7.7 must apply to this light level.
1.7.4 Optics: Dimensional requirements
Radiometer input aperture size must fit the light output apertures of both night vision goggle test sets
The aperture of the light source being measured is 0.950 inches +/- 0.002 inches. To ensure the radiometer fits easily into the test set aperture in a repeatable way (not too tight or too loose), the outer diameter of the radiometer light input aperture must be 0.944 inches so that the radiometer fits solidly yet easily into the output port of the test set light source.
1.7.5 Optics: Field of view, Full Width Half Max = 34.5 degrees (full angle), Out of target blocking for angle greater than or equal to 44 degree (full angle) 1:1000 (0.1%)
The full radiance measurement angle (field of view) of the optics of the radiometer must not be greater than that field of view angle of the output optics of the test sets. Otherwise, the full radiance measurement angle (field of view) of the radiometer will be under-filled which means that the radiometer is viewing a portion of the surroundings of the light source rather than only the light source itself, leading to increased uncertainties. A factor of 1000 out-of-target blocking is needed at a full radiance measurement angle of 44 degrees.
1.7.6 Optics: Focus fixed at infinity
The focus of the lens of the radiometer must be non-adjustable and fixed at infinity.
1.7.7 Relative expanded uncertainty (k=2): 2.0%
The relative expanded uncertainty (k=2) of the radiometric and photometric measurements made by the radiometer should be no greater than 2.0% once all factors such as source-detector distance dependence, short term stability, long term stability, and non-linearity are taken into account.
1.7.8 Instability of no greater than 1.0% at all required light levels
An instability of greater than 1.0% leads to increased overall uncertainties. Also, since instability often increases with a radiometer?s age, poor stability of new radiometers suggests poor confidence in the radiometer's long term performance. Stability is calculated in this case by taking the standard deviation of measurements taken over a period of several minutes at a constant light level and dividing the result by the average value.
1.7.9 Radiometer Non-Linearity as low as possible over light level range
Linearity in this case is the change in responsivity at differing light levels. Though non-linearity errors can be mitigated by reporting different responsivities at each light level measured, this can lead to significant errors if the light level measured during use differs from the value measured during calibration.
1.7.10 Immunity to the radiometer being ?blinded? by moderately high light levels
With the current radiometer, exposure to moderate light levels, such as those generated by a flashlight or room lights, makes the radiometer output temporarily unstable. In order to continue measurements, the user must wait 5 to 10 minutes with the radiometer exposed to darkness before the output of the radiometer is stable enough to continue taking measurements. This can lead to potentially large errors if the user inadvertently exposes the radiometer to moderate light levels without realizing it, or does not adequately wait the 5 to 10 minutes before the output stabilizes. Immunity to this "blinding" effect reduces the likelihood of errors during measurement.
1.7.11 Electronics
Decade signal gain selections are needed from 104 V/A to 1010 V/A
Gain switch errors must be less that 0.5 %
The detector must have a shunt resistance of minimum 2 Gigaohms and an active area of 1/3 cm^2 (5.8 mm x 5.8 mm) One example of this type of detector is the Hamamatsu S2592-04 (peaks at 960 nm, 5.8 mm x 5.8 mm detector area, in a TE cooled TO-8 package)
The detector temperature must be stabilized.
Detector cooling below room temperature is needed only if the shunt resistance at room temperature (or at an elevated stabilized temperature) is less than 2 Gigaohms.
Drift and Noise Equivalent Photocurrent: 3 fA (at 1010 V/A)
Point of Contact:
Please send all information/inquiries to: NAWCAD Lakehurst Rt. 547, Attn: Code 25200B562-3, Attn: Ms. Karin Weinert, Lakehurst, NJ 08733. (732) 323-1177, Karin.Weinert@navy.mil
Point of Contact
Karin Weinert, Contract Specialist, Phone 732-323-1177, Fax 732-323-7440, Email karin.weinert@navy.mil
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