Special Circuit for Altimeter

The MMK-4 altimeter is a full-function radio altimeter that meets aerospace standards; serving as a key component for longitudinal altitude channel control, it can be widely applied in cruise missiles and aircraft to measure altitude relative to the sea or ground. The MMK-4 adopts linear modulation coefficient technology adaptive to height changes and echo signal narrow-band receiving technology to enhance the product’s resistance to active interference, uses coherent local oscillator mixing to achieve superior performance in resisting co-frequency asynchronous interference, employs echo signal spectrum front detection technology to improve tracking accuracy, and follows the design principles of serialization, standardization, and modularization—endowing it with good product inheritance, maturity, and reliability.

The MY-70A radio altimeter is a solid-state C-band radio altimeter system based on frequency-modulated continuous wave (FMCW) technology, featuring constant beat frequency and closed-loop tracking measurement. It maintains a constant beat frequency by servo-controlling the slope of the sawtooth wave that modulates the microwave oscillator, thereby achieving automatic altitude tracking. Under the condition of a constant beat frequency, the measured altitude is proportional to the modulation period; thus, altitude information can be acquired by measuring the modulation period, and the system then converts this information into an altitude voltage for output. The MY-70A altimeter boasts excellent anti-jamming performance, thanks to its adoption of a narrow-band receiver (with gain adjustable according to altitude), as well as technologies including equivalent spectrum front-end detection, weighted frequency identification, and automatic servo tracking. Additionally, the altimeter’s high-frequency components are implemented with microwave integration, while its low-frequency components utilize a modular design—these measures collectively enhance the product’s reliability, anti-interference capability, and electromagnetic compatibility.

The MDG-400 radio altimeter operates in the C-band and adopts a frequency-modulated continuous wave (FMCW) working system, with its antenna utilizing a transmit-receive separation mode. Prior to missile launch, the altimeter (serving as the height-fixing device) is powered on, and it undergoes self-check and height presetting via the communication interface. After the missile is launched, the radio frequency (RF) module is activated, and frequency variation parameters are set based on the preset height. When the preset height is achieved, the altimeter outputs height-fixing command information and telemetry data. The MDG-400 altimeter features mature technology; its adoption of frequency-modulated continuous wave (FMCW) technology endows it with the advantages of compact size and a large height measurement range.

The MASS-15 Continuous Echo Simulation Excitation System of Radio Altimeter is a specialized testing equipment designed to support the performance verification, calibration, and development of radio altimeters. It focuses on generating stable, continuous echo signals that accurately replicate real-world altitude-related signal environments—including varying echo amplitudes, frequency characteristics, and delay parameters corresponding to different flight altitudes and terrain conditions. By providing these realistic simulated excitation signals, the system enables radio altimeters to operate under controlled laboratory conditions, allowing engineers to test key functions such as height measurement accuracy, continuous tracking stability, and anti-interference capability. Its reliable continuous echo simulation function not only replaces the need for complex and costly field tests but also ensures consistent, repeatable test results, making it an essential tool for ensuring the reliability and performance of radio altimeters in practical aviation applications.