ALT ODL

Our RADAR Altimeter Optical delay Line (ALT ODL) is typically used for test and calibration. It is an efficient, compact and accurate instrument used to simulate, roundtrip altitudes, range and distances during RADAR and Altimeter production and test.

Our ALT ODL product family addresses a growing demand for test and calibration of Altimeter radars. It represents the optical delay in terms of altitude, range or distance (two-way). ALT ODL products typically operate below 6GHz in the L, S and C bands. They use our direct modulation programmable RFoF converters. A fixed altitude ALT ODL with altitudes up to 15000ft may be provided in a Mini-ODL enclosure.

The RF input signal is converted into a modulated optical signal, which is then transmitted into a single mode fiber, creating a fixed time delay defined by the fiber length corresponding to a desired altitude. After passing through the fiber, the optical signal is converted back into an electrical RF signal, identical to the input RF signal.
The ALT ODL can be configured to emulate a single altitude or up to more than 2 24 altitude steps (24bits) with a minimum step of 0.5ft (15cm).

Use the RFQ form to submit a complete definition of an ALT ODL requirement. The form prompts specifying the properties of the desired ODL including:

  • Frequency range
  • Altitude, range or distance value or range and step
  • Zero state, bypass option
  • RF input power, max. receiver bandwidth
  • Gain
  • Delay switching speed, control
  • Enclosure, power
  • Other requirements

The Altimeter ODL offers very high accuracy better than 0.3ft (10cm) in the smallest main segments for altitude steps under 6ft and >0.1% above. The maximum altitude can reach 100,000 feet or 30Km in one enclosure.

The Mini Optical ALT ODL provides a compact, high performance solution for testing and calibrating radar systems featuring accurate time delay with ultra low noise. ALT ODL solutions up to 6 GHz are based on direct modulation Programmable RFoF, while for higher frequencies indirect modulation RFoF is preferred.

FAQs

What is RFOptic's Altimeter Optical Delay Line (ALT ODL)?
The ALT ODL is RFOptic's optical delay line product designed specifically for radar altimeter testing, simulating the RF delay corresponding to different altitudes so altimeter systems can be verified on the ground.
How does RFOptic's ALT ODL simulate altitude during testing?
The ALT ODL converts the altimeter's RF signal to light, passes it through a fiber length (or programmable delay) corresponding to the desired simulated altitude, then converts it back to RF - replacing the need for actual flight testing at that altitude.
How can I simulate different altitudes when testing a radar altimeter without a live flight test?
Radar altimeter systems are commonly tested on the ground using an optical or RF delay line (such as RFOptic's programmable/progressive ALT ODL) that introduces a controlled delay matching the round-trip time of the desired simulated altitude, avoiding the cost and risk of live flight testing.
What technology replaces flight testing for radar altimeter verification?
Optical delay lines are widely used to replace or supplement flight testing for radar altimeter verification, simulating the RF round-trip delay of a given altitude in a lab environment.
Features
  • Altitude range 0.5ft to 100,000ft with custom steps
  • Display Delay, Round-trip Distance, Range or Altitude
  • Supports frequencies from 1MHz up to 6GHz
  • Handles all altimeter RF signals, encoding, and protocols, including Pulse and CW signals
  • Delay accuracy of 0.1%
  • Amplitude Control with 30dB LNA On/Off and 31.5dB 0.5dB step input and output attenuators
  • Excellent Phase Noise
  • High dynamic range
Applications
Radar Calibration Testing
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Altimeter
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Options
  • Mini ODL
  • RF and Optical bypass
  • DC Power
  • External Delay(s) 
  • Optical Power Indication
  • Built in diagnostics
  • Doppler modulation
Monitoring

RFOptic’s ALT ODL systems may be controlled directly from the front panel with an LCD display and a 3-button navigation pad. Such systems can also be controlled using USB or Ethernet M&C interfaces as well as via documented API.