This page highlights many of the joint JPL-UCLA instrument and sensing projects we've done, including several sub-orbital, UAV and airborne missions. Note: all the work and images shown here are taken from previously published materials. Check the publication page for more details on these projects.
InP-CMOS Wildfire Imaging Radiometer
This work sought to develop a very compact imaging radiometer for imaging fire lines through smoke from extremely compact UAV platforms. The radiometer itself is a CMOS chip carrying the receiver and baseband circuitry with an single InP pre-amplifier stage. The radiometer uses a low-loss meta-surface antenna with the entire system centered at 94 GHz which offers a reasonable tradeoff between atmospheric & smoke absorption vs. spot resolution on the ground from modest altitudes.
Compact Low Energy Version of Electra Radio (CLEVER) Proximity Radio for Mars Surface Missions
The Compact Low Energy Version of the Electra Radio (CLEVER) is an almost all-digital transceiver designed specifically for Mars surface missions. It operates with the same protocol, bands, channels and modulation as the Electra radio that has been the backbone of NASA missions to Mars for over 20 years. CLEVER is 100% compatible with the NASA proximity-1 protocol that all current Mars surface missions and orbiters use including Mars Odyssey, Mars Express, and MRO. CLEVER directly oversamples the UHF carrier used for Mars proximity telecom and performs all operations (modulation, up/down conversion, channelization and DPD/EQ) directly in the frequency domain. The digital nature makes it robust across wide temperature ranges and extremely radiation tolerant. Beyond regular transceiver functions it supports a hailing function (that allows a wake up! signal to be received from a low power state during the Mars winters) and a carrier turn-around function that's used for ranging and radio science.
Whatsup-2 (WS-2) Sub-Orbital Mission 2023
Payload
|
WS-2 Launch
|
WS-2 Prelaunch Ops
|
|
|
|
|
This was the second flight of the Water Hunting Advanced Terahertz Spectrometer on an Ultrasmall Platform (WHASTUP) designated WS2. This experiment had the next generation of WHATSUP spectrometer which evolved from the earlier version flown on the WS-1 mission. The WS-2 mission featured a new temperature controlled calibration load, as well as a more advanced lens antenna and performed several soundings of Ozone in near space as an instrument demonstrated. The launch and flight took place on July 16 2023 and flew sub-orbitally from Palestine Texas to a remote area about 30 miles east of San Angelo, Texas.
"SpecChip-2" Dual Band 100 GHz / 200 GHz Fabry-Perot
Cavity Ring-down Spectrometer
SpecChip2 (SC2) builds on our original SpecChip work for in-situ exploration of comets, asteroids and other primitive planetary bodies which emit volatiles from there surfaces. SC2 re-imagines the instrument geometry with cavity excitation on two axis provided by a set of 4 CMOS chips. Two of the chips are a 100 GHz Tx-Rx pair in the horizontal axis while a second 200 GHz Tx Rx pair is placed along the vertical axis, all exciting the same Fabry-Perot cavity. This lets us capture the 183 GHz water feature as well as HDO at 80.6 GHz to access D/H ratio.
Enhanced Meta-Surface (EMTS #2/3) Snow Radar UAV - 2022
EMTS 2 and 3 are newer radars based on our original EMTS1 concept from 2020. They have improved close in dynamic range over the original EMTS 1 system using an improved electronic Tx-to-Rx leakage cancellation & calibration scheme in the SoC as well as a second generation design of MetaSurface antenna. These radars at both C and Ku band can achieve 80-90dB of dynamic range and produce the excellent radargrams seem above. EMTS 2 and 3 traveled all over in winter 2022-2023 with measurements conducted in Idaho (Boise area), Colorado (Grand Mesa area) and even northern Alaska where we the snow on top of Sea ice.
EMTS2 in flight
|
EMTS2 Radar testing
|
|
|
|
Whatsup-1 (WS-1) Sub-Orbital Mission 2021
WS-1 Launch
|
WS-1 Flight Compatibility Test
|
|
|
|
The Water Hunting Advanced Terahertz Spectrometer on an Ultrasmall Platform (WHASTUP or WS) experiment is the next generation 600 GHz spectrometer which evolved from the earlier version flown on the ReckTangLE-II mission. The WS-1 mission featured a widerband CMOS synthesizer, and an updated MEMs based waveguide Dicke switch for radiometric calibration. WS-1 primarily observed water vapor and Ozone in Earth's stratosphere. The launch and flight took place from Aug 20 2021 and flew sub-orbitally from Ft. Sumner NM to a remote area about 40 miles south of Albuquerque NM.
Ground Penetrating Radar for Mars Science Helicopter
The Mars Science Helicopter (MSH) concept is a larger version of Mars helicopter that carries science instruments. We have been developing an extremely lightweight GPR module to fit this helicopter platform to study the sub-surface, specifically ice deposits at Mar's polar regions. The MSH GPR has several challenges that make it far more challenging than a regular GPR. First, the antenna has to stow and deploy for entry descent and landing on mars meaning the structure is not rigid and the S-parameters of the antenna need to continuously be calibrated. Second, the integration time is much shorter than a traditional GPR since the helicopter has to perform science during fast traverse operations, so we need single chirp ranges of 100-110 dB which we achieve through a tremendous amount of both foreground and background calibration. Finally the MSH GPR is a single antenna (mass the helicopter can support is restrictive) making Tx to Rx isolation in order to support that 110dB dynamic range extremely challenging.
Enhanced Meta-Surface (EMTS #1) Snow Radar UAV - 2020
To respond to the drought situation in the southwestern US, we've been developing the enhanced-metasurface (EMTS) radar, a drone-based radar system at C and Ku band specifically for measuring snowpack properties (density, depth, liquid water content,..) in order to provide an estimate of Snow-Water Equivalent (SWE). SWE is a parameter that describes how much water is available from the snowpack in a given year and is critical for water resource planning. The EMTS radars use advanced antenna technology that allows for a compact UAV-compatible structure that still offers high-gain and excellent isolation between transmit and receive pathways. C and Ku band provide reasonable penetration into both dry and wet snowpacks, however the top snow-air interface is still a fairly week reflection so a non-trivial 70-80 dB dynamic range is still needed (automotive radar is more in the 30-40 dB range). To accomplish this we use several feed-forward based leakage cancellation methods within the radar electronics to both pre-cancel and post-calibrate out transmit leakage.
Compact Adaptive Microwave Limb Sounder
The Compact Adaptive Microwave Limb Sounder (CAMLS) is a 340 GHz limb-sounder that flies on the ER-2 platform. Unlike other limb-sounders we show here (REckTangLE, WHATSUP, ...) this one has a cryogenic cooled front end and allows much better Tsys than a room temperature receiver. CAMLS takes advantage of that lower Tsys to reduce measurement integration time and provide a second access of scanning during flight. The CAMLS instrument looks at several species in the 340 GHz band including water vapor, ozone, and other traces gasses in the stratosphere. CAMLS flies on the NASA ER-2 aircraft, a NASA version of the U2 spy plane for high-altitude research that's based out of NASA Armstrong Flight Research Center (AFRC) in Palmdale, CA.
Stratospheric Water Vapor Inventory by Convective Hydration (SWITCH) Instrument
The Stratospheric Water Vapor Inventory by Convective Hydration or SWITCH instrument is a technique for measuring water vapor that arises from small convective plumes that loft water vapor through the tropopause and into the stratosphere during severe weather events. SWITCH seeks to inventory how much water is transported to the stratosphere through this process and uses an interesting 380 GHz absorption measurement configuration to accomplish this. SWITCH operates 3 transmit cubesat spacecraft each transmitting 4 unique tones about the 380 GHz water line and one larger receive spacecraft placed on the limb that receives all 4 sets of tones from all spacecraft resulting in a comb like structure that allows the water vapor line at 380 GHz to be profiled. As the different cubesats are at different limb altitudes from the receiver's field of view, high resolution vertically resolved measurements of the convective plumes can be made. As the transmit power at 380 GHz is limited and the distances involved are long, we use a locking direct-digital down-converter to tightly channelize the tones at the receiver to hold sufficient SNR. Also since we're picking out ~20KHz bandwidth at 380 GHz absolute frequency stability is super critical so everything in the project (TX side and RX side) are referenced to rubidium atomic standards.
Planetary Exploration DS/SS Based Ground Penetrating Radar
Since 2019 we have been developing a wideband DS/SS ground penetrating radar (GPR) system for applications like exploring the sub-surface of Mars or the moon for ice deposits and possible sub-surface water sources. DS/SS has several advantages over traditional FMCW radar, notably it doesn't require any analog components (no DACs, ADCs, or RF elements) and is truly all-digital, making it relatively immune to the wide range of temperatures and radiation effects that are encountered in planetary exploration.
ReckTangLE-2 (RT-2) Sub-Orbital Mission
The Reck-Tang Limbsounder Experiment-II (ReckTangLE-II) is an update of the two band spectrometer we attempted to fly in 2018. The 180 GHz "Tang" channel features a 180 GHz CMOS 28nm receiver and 0.35nm InP Hempt pre-amp and custom back end 6GS/s processing chip with integrated ADC. This channel is focused on mapping water vapor via the 183.310 GHz H2O rotational line. The "Reck" 550 GHz channel included a MEMs based calibration dicke switch and CMOS frequency synthesizer and a second 6GS/s back-end processing chip. This channel is focused on mapping how pollution moves through the atmosphere specifically detecting NO2 and O3. Unlike ReckTangLE which was piggyback on the JPL Remote ballooncraft, ReckTangLE-II is a self supporting space vehicle and has it's own navigation.tracking and command/telemetry systems as well as it's own power system and landing/recovery system. ReckTangLE participated in the 2019 NASA high-altitude balloon campaign operated by the Columbia Scientific Balloon Facility (CSBF) in Ft. Sumner, New Mexico and was launched on Oct 17 2019 and landed just west of Matador Texas where a large crater remains.
The fight data archive is available at: RT2_FLIGHT_DATA
The fight data archive is available at: RT2_FLIGHT_DATA
RT2 Flight Compatibility Test
|
RT-2 In flight camera
|
RT2 Launch
|
|
200 GHz Direct Sequence Spread Spectrum Radar
We've been exploring direct-sequence spread spectrum radars as an alternative to FMCW sensing radars for several of our UCLA and JPL projects related to sensing ice, snow surfaces, and maybe altimetry. DS/SS works by transmitting spread-spectrum sequences and correlating in time domain avoiding requiring an FFT processor like an FMCW system. DS/SS offers several advantages including that there is no range foldeover or "ambiguity range" as the transmitted sequence is not periodic unless you consider the timescales of weeks. It also has the added property that its impulse point return function is sharper than an FMCW chirp radar, giving better dynamic range tightly spaced targets with vastly different reflection intensities (often the case for ice and dust sensing). the only drawback is the dynamic range does not improve with distant targets, so if you are looking only at widely spaced bright targets (like cars), FMCW radar is probably a better choice.
| dsss_radar.mp4 |
ReckTangLE-1 (RT-1) Sub-Orbital Mission
The Reck-Tang Limbsounder Experiment (ReckTangLE) is a two band CMOS spectrometer developed for high altitude balloon flights in the upper stratosphere (the edge of space). The instrument detects and maps water vapor as well as several other pollutants. The ReckTangLe features a 500-600 GHz spectrometer band focused on NO2, O3, and other pollutant spectral lines, with the front-end receiver provided by the JPL sub-millimeter wave group. The LO is implemented using a CMOS W-band frequency synthesizer for the base LO generation, as well as our 3 GHz bandwidth CMOS spectrometer processor. The second band is a 180 GHz receiver implemented entirely in 28nm CMOS except for a single InP pre-amplifier stage to improve system noise temperature. The 180 GHz receiver is focused on the H2O line at 183.31 GHz. Base-band spectrometer processing was again provided by our 3 GHz processor chip. ReckTangLE participated in the 2018 NASA high-altitude balloon campaign operated by the Columbia Scientific Balloon Facility (CSBF) in Ft. Sumners, New Mexico.
Ku Band Snow Sensing Radar
Sample of FMCW data collected from Mammoth, CA:
|
The Ku-Band radar system is a project with UCLA and JPL that began in 2016 under JPL Earth Science funding with the purpose of sensing snow-packs in the Sierra Nevada and other mountain ranges to estimate the snow depth, snow coverage, melted liquid water content and snow density. These radar measurements are important as they provide a path for remotely estimating the snow water equivalence or “SWE” which describes the amount of water available during the melting season, a quantity critical for water resource planning during drought conditions.
The radar we developed is an FMCW Ku-Band (15 GHz) 65nm CMOS SoC with 2 GHz bandwidth that contains all the required FMCW radar functional blocks including radar waveform generation with a (DDFS/DAC based chirper) all the RF components (Tx, Rx, LO) and base-band receiver digital electronics. The radar was packaged in a JPL instrument package with telemetry, and weatherproofed antennas for deployment in the field with network connectivity. We currently have one system operating at the CUES site at Mammoth mountain resort in cooperation with Prof Dozier at UCSB, and have a second system deployed with Prof. HP Marshall at Boise state. | ||
50-200 GHz Hybrid InP-CMOS Radiometers for Remote Sensing
NASA, NOAA and others rely on passive sensing from Earth’s orbit not only for daily weather forecasting, but also for measuring moisture in the lower stratosphere / upper troposphere for climate science, and for sensing storms to diagnose extreme weather. The goal of our hybrid radiometer work was to implement a passive sensing radiometer instrument in CMOS technology at 104 GHz (O2) and 183 GHz (H2O) that was compact enough, and low enough power enough to be carried on a 1U (10cm x 10cm x 10cm) cube-satellite using only 1W of DC power.
In order to overcome the poor noise and limited sensitivity of CMOS receivers, we combined a custom CMOS SoC containing a receiver, synthesizer, ADC, and digital back-end processor with an ultra-low-noise InP LNA to form a complete radiometer system sensitive enough to measure water and oxygen distribution in extreme storms. While the 100 & 180 GHz RF components represent challenging design work, even more critical was developing the calibration algorithms used within the embedded DSP portion to drift-stabilize the instrument (so that gain remains constant with temperature and over time) as the measurements need to occur over long time periods compared with the receiver’s Allan variance (the intrinsic time a receiver is stable for without calibration applied).
As a further demonstration of the sensitivity, the hybrid radiometer instrument was reconfigured as a passive mm-wave imager and several passive images were taken in the laboratory. [demo]
Gamma Radiation Sensors for Intelligent Space SoC Calibration
Adapting to gamma radiation and specifically total-ionized dose (TID) is a critical part of any intelligent calibration system for a deep space instrument. While single-event effects are the dominant challenge for spacecraft computers, these transient events are essentially harmless to space instruments as they only create momentary frames of “bad data” in long measurement campaigns. Alternatively total ionized dose (primarily a gamma radiation effect) creates permanent changes in semiconductor devices, which lead to gain or offset changes in highly sensitive instrument systems.
These instrument changes from TID occur over a mission’s lifetime and can create an underlying biases and artificial trends in science data, and therefore need to be tracked and corrected. For this purpose we’ve developed a CMOS radiation sensor (dosimeter) circuit that tracks the TID and informs our on-chip calibration systems of radiation conditions. The sensor is employed standard as part of calibration in all the space SoCs we’ve developed between UCLA & JPL in the last 3 years. The sensor operates by comparing the threshold of an I/O device with the threshold voltage of a core logic device, while designing their dimensions so that their temperature coefficients are identical, cancelling thermal effects when sensed differentially. While their temperature coefficients are identical, their radiation behavior is not, allowing the sensor to distinguish between threshold voltage changes due to thermal effects and threshold voltages due to actual radiation exposure.
These instrument changes from TID occur over a mission’s lifetime and can create an underlying biases and artificial trends in science data, and therefore need to be tracked and corrected. For this purpose we’ve developed a CMOS radiation sensor (dosimeter) circuit that tracks the TID and informs our on-chip calibration systems of radiation conditions. The sensor is employed standard as part of calibration in all the space SoCs we’ve developed between UCLA & JPL in the last 3 years. The sensor operates by comparing the threshold of an I/O device with the threshold voltage of a core logic device, while designing their dimensions so that their temperature coefficients are identical, cancelling thermal effects when sensed differentially. While their temperature coefficients are identical, their radiation behavior is not, allowing the sensor to distinguish between threshold voltage changes due to thermal effects and threshold voltages due to actual radiation exposure.
30-200 GHz mm-Wave Synthesizers For Planetary Instruments
At the core of most mm-wave radar, radiometer, and spectroscopic sensing systems are high precision local oscillators (LO) to provide down-conversion in heterodyne sensors, as well as provide the transmit carrier for active sensors. Most instruments have previously relied on dielectric-resonance oscillators (DROs) to provide these highly precise LO signals, however DROs consume considerable power (>5W) and mass (>3Kg) making them difficult to fly on planetary missions (orbiters, landers, and rovers) where payload is extremely limited, as well as compact platforms like UAVs and Cube-satellites. To overcome this, our CMOS team developed a compact CMOS-based LO module. The core of the 0.5W / 100g module is a CMOS system-on-chip that contains a 50 GHz mm-wave frequency synthesizer, a fractional delta-sigma divider chain, a 100 GHz frequency doubler and a 100 GHz power amplifier. A final stage 200 GHz doubler allows the module to be configured for either 100 GHz band or 200 GHz band output.
Unlike a simple synthesizer used in wireless communications, we’ve developed a tremendous amount of digital processing for both calibration of the module, as well as ensuring reliable operation in a harsh space environment (extreme temperatures and radiation effects). Beyond the basic RF circuitry, the SoC chip contains a suite of sensors including output power, phase-lock quality, temperature, and radiation monitors, as well a digital processor running several algorithms that constantly adjusts circuit parameters to adapt for temperature and radiation changes to maintain acceptable output power and phase noise performance. The SoC is packaged in a spaceflight compatible housing that provides a WR5 or WR10 (depends on output band) waveguide connections for the LO output.
Unlike a simple synthesizer used in wireless communications, we’ve developed a tremendous amount of digital processing for both calibration of the module, as well as ensuring reliable operation in a harsh space environment (extreme temperatures and radiation effects). Beyond the basic RF circuitry, the SoC chip contains a suite of sensors including output power, phase-lock quality, temperature, and radiation monitors, as well a digital processor running several algorithms that constantly adjusts circuit parameters to adapt for temperature and radiation changes to maintain acceptable output power and phase noise performance. The SoC is packaged in a spaceflight compatible housing that provides a WR5 or WR10 (depends on output band) waveguide connections for the LO output.
100 GHz Cavity Ring-down Spectrometer-on-a-Chip "SpecChip"
The Spectrometer on a Chip or “SpecChip” is a fully CMOS instrument developed at JPL from 2015-2017. The SpecChip is the very first all-CMOS spectroscopy system (TX and RX) that has demonstrated enough sensitivity to detect trace volatiles, and one of the smallest and lowest power spectroscopy instruments in NASA’s portfolio as of 2018. The SpecChip contains two SoCs, a transmitter and a receiver that first excite trace gases in an open resonant cavity (frequency tunable by a motor that adjusts the mirror position) with a pulse of mm-wave energy, and then detects the molecular ring-down from rotational responses that lie in band of the cavity and transceiver set. As the detection greatly depends on the pulse width, the mm-wave pulses are extremely precisely controlled with an integrated digital processor to control the pulse waveform (slope, duty cycle, repetition rate) as well as excitation power and other parameters, allowing the system to optimize itself for specific gasses during detection. The entire SpecChip instrument weighs only 1 Kg including transceivers, mirrors and motor, and consumes only 600mW of DC power from a spacecraft or lander during operation.
Wide-band Spectrometer Processors for Planetary Science
While the RF components for THz remote sensing systems have improved tremendously in the last 5 years with the appearance of InP hemt amplifiers (up to 800 GHz) and new silicon micro-machined integration, digital wide-band spectral processing has remained limited to FPGA solutions which consume far too much power (>30W) for most planetary missions and even some spaceborne astrophysics platforms (where large receiver arrays with 100s of pixels are being planned). To address this planetary science and astrophysics need, we have recently developed CMOS-SoC wideband spectral processors which provide much higher processing capability than existing FPGA solutions, with much less power consumption. The latest in this series of SoC chips employs a wideband 6 GS/s ADC mated with an 4096 point FFT processor and integrated SRAM accumulator to capture the time-domain output signals from THz receivers and compute the power spectral density. As these spectrometer processors are intended for use on planetary missions where extreme radiation and temperature effects exist, several intelligent and adaptive calibration algorithms are embedded within the processor to adjust a wide range of parameters related to the interleaved ADC including timing skew, radiation annealing effects on the comparators, and the dependence of the ADC channel mismatch effects on both extreme temperatures and high total ionized doses.
Wide-band Near-Surface Radar for Planetary Science
Beyond the snow radar work done at Ku-Band (15 GHz range) there is an interest in developing wide-band radars with similar waveform bandwidths, at even lower frequencies allowing for better penetration. Applications focus on the detection of buried ice and snow thought to be on the surface of Mars at high latitudes, as well as characterization of near surface ice (porosity, stratigraphy, and melted materials) on comets and other primitive bodies in the solar system. Our UCLA/JPL team developed the above wide-band (1 GHz chirp bandwidth) FMCW radar centered at 500 MHz based on a fully digital architecture (no up or down conversion). The radar SoC uses a 128Kpt 2.5GS/s AWG with DACs and ADCs to produce and capture the waveform chirps directly, requiring only an external wide-band PA to raise transmit power. In the above example we sensed several classrooms on the UCLA campus from outside the building and were able to detect the cross-sectional structure.