Ainstein US-D1 User manual

2029 Becker Dr
Lawrence, KS 66047
Radar Altimeter
US-D1
User Manual
D00.02.04
11/04/2021
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2029 Becker Dr
Lawrence, KS 66047
Revision History
Version Number
Date
Authors
Notes
D00.00.01
Mar 2, 2018
Jin Cheng, Sheen Xiao
Draft based on
engineering spec and
customer
requirements
D00.00.02
April 10, 2018
Jin Cheng, Sheen Xiao
Put customer
requirements in
development phases
D00.00.03
September 10, 2018
Zhenyu Hu
Update specs and
features.
Add data format and
communication
protocol
D00.01.01
October 5, 2018
Andrew Megaris
Technical Revision
D00.02.00
June 24, 2019
Zhenyu Hu
Revision for FCC
certificate
D00.02.01
October 23, 2019
Andrew Megaris
Final FCC Edit
D00.02.02
October 14, 2020
Zhenyu Hu
Add Firmware version
information
D00.02.03
January 8, 2021
Zhenyu Hu
Update the Specs
D00.02.04
November 1, 2021
Camron Myers
Installation
Instructions,
Operational
Requirements,
Product Description
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2029 Becker Dr
Lawrence, KS 66047
Copyright 2019 © Ainstein AI, Inc. All rights reserved. No part of this work may be
reproduced, published, or distributed in any form or by any means (electronically,
mechanically, photocopying, recording, or otherwise), or stored in a database retrieval
system, without the prior written permission of Ainstein AI, Inc. in each instance.
Warning!
FAILURE OR IMPROPER SELECTION OR IMPROPER USE OF THE PRODUCTS AND/OR
SYSTEMS DESCRIBED HEREIN OR RELATED ITEMS CAN CAUSE DEATH, PERSONAL
INJURY AND PROPERTY DAMAGE.
• This document and other information from Ainstein AI Inc, its subsidiaries and authorized
distributors provide product and/or system options for further investigation by users having
technical expertise.
• The user, through its own analysis and testing, is solely responsible for making the final
selection of the system and components and assuring that all performance, endurance,
maintenance, safety and warning requirements of the application are met. The user must
analyze all aspects of the application, follow applicable industry standards, and follow the
information concerning the product in the current product catalog and in any other materials
provided from Ainstein or its subsidiaries or authorized distributors.
• To the extent that Ainstein or its subsidiaries or authorized distributors provide component
or system options based upon data or specifications provided by the user, the user is
responsible for determining that such data and specifications are suitable and sufficient for
all applications and reasonably foreseeable uses of the components or systems.
• The Buyer and/or end-user will be solely responsible for final disposal of all products.
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2029 Becker Dr
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Table of Contents
Title Page 1
Table of Contents 4
1. Product Description 5
1.1. US-D1 5
1.2. Compliances 5
2. Installation Guidelines 6
2.1. Mounting Angle 6
2.2 Mounting to an Aircraft 6
2.3. Line of Sight Clearance 6
2.4. Integration Requirements 7
3. Operational Requirements 8
3.1 Obstruction to the US-D1 Field of View 8
3.2 Excessive Pitch/Roll 8
3.3 Terrain 8
3.4 Power Source 8
3.5 Orientation of US-D1 8
3.6 Minimum and Maximum Operating Altitude 8
4. Technical Specifications 9
5. Data Protocol For US-D1 11
5.1 UART Data Protocol Specifications 11
5.2 CAN Data Protocol Specifications 12
6. Mechanical Specifications 14
7. Radiated Emissions 16
8. Hardware Interface 16
9. Accessories & Peripherals 17
10. Application Notes 18
11. Hardware & Firmware Version 20
12. Firmware Changelog 21
13. Contact Us 23
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2029 Becker Dr
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1. Product Description
1.1. US-D1
The US-D1 Radar Altimeter uses the principles of radio detection and ranging to
determine the altitude of the aircraft. A microwave signal is transmitted out of the
sensor, reflects off the target and is received by the sensor. Distance from the sensor to
the terrain (altitude) is derived by the difference in time from when the signal is sent
from the sensor to when the signal is received by the sensor
The US-D1 is enclosed in a black plastic case, the radome, which is conducive to radar
telemetry. The US-D1 has a short cable terminated with a connector.
Custom units with different cable lengths and connector types may be configured for
OEM customers. Contact Ainstein for more information.
1.2. Compliances
FCC ID: 2ATMB-USD1AZ
This device complies with Part 15 of the FCC rules. Operation is subject to the
following two conditions: (1) This device may not cause harmful interference, and (2)
This device must accept any interference received, including interference that may
cause undesired operation.
This equipment has been tested and found to comply with the limits for a Class B
device (commercial or industrial use), pursuant to Part 15 of FCC rules. These limits are
designed to provide reasonable protection against harmful interference when the
equipment is operated in a commercial environment. This equipment generates, uses
and can radiate radio frequency energy and, if not installed and used in accordance
with the instruction manual, may cause harmful interference to radio communication.
Operation of this equipment in a residential area is likely to cause harmful interference,
in which case the user will be required to correct the interference at his/her own
expense.
CE Compliance
This device complies with Directive 2014/53/EU of the EU declaration of conformity.
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2. Installation Guidelines
Warning! Follow the manufacturer's regulations when mounting, modifying, repairing,
and maintaining equipment. The manufacturer assumes no responsibility for any
accidents caused by incorrectly mounted or incorrectly maintained equipment. The
manufacturer assumes no responsibility for the system being incorrectly applied, or the
system being programmed in a manner that jeopardizes safety.
The following instructions are critical to the proper operation of the US-D1 device.
Failure to install the unit according to the given instructions can result in malfunction of
the device.
2.1. Mounting Angle
When mounting the device, the front face of the US-D1 must be perpendicular to the
ground below the aircraft. There should not be any angle of inclination in any direction
while the device is fastened to the aircraft.
Figure 1
2.2 Mounting to an Aircraft
The device should be secured to the aircraft, where it is not free to move in any
direction.
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2.3. Line of Sight Clearance
Keep the face of the radar clean, and do not cover it with any additional materials. Any
coatings, coverings, and modifications to the radome can degrade the performance of
the radar device.
Additionally, keep any unexpected objects out of the radar’s FoV (Field of View).
Obstructions to the US-D1’s field of view will cause a decrease in the performance of the
radar. It is highly recommended that the US-D1 be mounted on the underside of the
aircraft far away from the landing gear, other aircraft structures, or other equipment.
Figure 2
2.4. Integration Requirements
The US-D1 outputs altitude measurements and signal-to-noise ratio (SNR)
measurements when operational. When integrating the US-D1 radar altimeter, it is
necessary to use both altitude and SNR measurements to properly filter out erroneous
altitude values.
Caution! Altitude measurements associated with a SNR value of 13dB or lower are
considered erroneous.
The altitude measurements should not in any circumstances be used as true
measurements independently of the corresponding SNR values.
A filtering algorithm should be used to estimate vehicle position, velocity and
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angular orientation based on rate gyroscopes, accelerometer, compass, GPS, airspeed
and barometric pressure measurements in addition to the recorded US-D1
measurements. Sensor redundancy is heavily advised for the US-D1.
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3. Operational Requirements
The US-D1 will perform optimally if the operational requirements below are fully
satisfied. Failure to meet the operational requirements may cause a decrease in
performance, accuracy, or reliability of the US-D1 altimeter and is not advised.
3.1 Obstruction to the US-D1 Field of View
Objects or aircraft structures that are located within the US-D1’s conical field of view
which obstruct the radar’s view of the ground may cause multipath reflections or other
degrative phenomena to occur. The US-D1 should be mounted a safe distance away
from the landing gear and any other components of the aircraft below it.
3.2 Excessive Pitch/Roll
Pitch and roll angles that exceed 21.5° and 15° respectively may also cause the
performance of the US-D1 to worsen. This sensitivity increases with altitude.
3.3 Terrain
Terrain with poor reflectivity may cause the performance of the US-D1 to worsen.
Flying at the limit of the US-D1’s range over dry, loose soil, such as tilled farmland, or
sand is not recommended.
3.4 Power Source
Any power source used to operate the US-D1 that does not provide the minimum
power and voltage can worsen the performance of the device or cause it’s operation to
stop altogether.
3.5 Orientation of US-D1
The US-D1 must be mounted upon the aircraft in such a manner as to be fully
horizontal, it’s radome directly facing the ground. Any angle of inclination may
degrade performance.
3.6 Minimum and Maximum Operating Altitude
Operating the US-D1 at altitudes below 0.5 meters and above 50 meters will result in a
degradation of performance and potentially erroneous measurements.
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4. Technical Specifications
Table 1: Specifications
Frequency
Band
24 GHz
Bandwidth
190 MHz
Minimum
Operating
Altitude
0.5 meters
Maximum
Operating
Altitude
50 meters
Altitude
Precision
6.0cm (< 1m), 4.0cm (> 1m)
Field of View
43 ° x 30 °
Interface
UART, CAN
Update Rate
100 Hz
Supply Voltage
5V~13V DC (5.5V recommended)
Power
Consumption
2W(at 5 Volts DC input)
Operational
Temperature
Range
-20 °C ~ 65 °C*
Size
108 x 79 x 20 millimeters
Weight
110 grams
Environmental
Conditions
IP67(with sealant)
Notes:
● All specs above are measured under the environment of 35 °C temperature,
standard atmospheric pressure and humidity, without any Electromagnetic
Interference (EMI).
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● Operational Temperature Range indicates radar works properly in this range. If
operating temperature goes beyond this range, radar might not be accurate and
can suffer mechanical damage.
● The radar unit can be shipped with either CAN or UART for it’s output data
protocol.
● * Operational Temperature Range is based on the hardware’s subcomponent
specifications. Actual operational testing is still pending.
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5. Data Protocol For US-D1
5.1 UART Data Protocol Specifications
● Baud Rate: 115200 b/s
● Data bit: 8
● Parity bit: N
● Stop bit: 1
● Voltage Level: 3.3V
A single data packet consists of six(6) bytes. Table 2 defines the packet structure.
Table 2: UART Data Packet Definition
From
US-D1 Altimeter
To
Receiver
Byte
Data
Note
1
0xFE
Packet Head
2
0x02
Version ID
3
0x**
Altitude (Least Significant 8 Bits)
4
0x**
Altitude (Most Significant 8 Bits)
5
0x**
SNR
6
0x**
Checksum (see formula below)
Notes:
● '*' refers to a variable bit containing dynamic data.
● Altitude: The altitude bytes can be combined (total 16 bits) to represent the
altitude information in centimeters. The structure would be: 0x[MSB][LSB],
where MSB and LSB are each two hexadecimal numbers (8 bits).
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● Checksum: The Checksum Byte could be used in the following:
○ checksum = (Version_ID + Altitude_H + Altitude_L + SNR) & 0xFF
○ If checksum = 1, check passed
○ if checksum = 0, check failed
5.2 CAN Data Protocol Specifications
● Baud Rate: 1 Mb/s
● Frame ID: customized (Standard Frame, Extended Frame)
● Standard: CAN Protocol 2.0 section A and B, ISO 11898-1:2015,-4
A single data packet uses four bytes of either a Standard or Extended CAN frame. The
type of CAN frame used and CAN ID of the device can be customized. The CAN frame
is defined in table 3.
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Table 3: CAN Frame Data Packet Definition
From
US-D1 Altimeter
To
Receiver
Byte
Data
Note
StdID
0x***
Standard ID frame
EtdID
0x********
Extended ID frame (Default 0x00090002)
1
0x**
Altitude (Most Significant 8 Bits)
2
0x**
Altitude (Least Significant 8 Bits)
3
0x**
SNR(Most Significant 8 Bits)
4
0x**
SNR(Least Significant 8 Bits)
5
0x00
(Reserved)
6
0x00
(Reserved)
7
0x00
(Reserved)
8
0x00
(Reserved)
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6. Mechanical Specifications
Figure 3: Dimensions of US-D1 (Units: mm)
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Figure 4: Field of View Orientation of US-D1
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7. Radiated Emissions
The output field strength generated by the US-D1 is within the acceptable range set by
the FCC and CE.
Maximum Transmit Power (EIRP)
25 dBm
8. Hardware Interface
Table 4: Data Packet Definition
Wire Color
UART
CAN
Black
Ground
Ground
White
RX(Radar)
CAN_LOW
Green
TX(Radar)
CAN_HI
Red
Voltage(5~13V)
Voltage(5~13V)
Figure 5: US-D1 Cabling Interface
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9. Accessories & Peripherals
9.1. Firmware Update Kit
The US-D1 Firmware Update Kit is an external device that can update the firmware of
the US-D1 radar altimeter. The Firmware Update Kit contains an update tool, a USB
connector, and power cable. The Kit allows the US-D1 to connect to the Firmware
Update Tool via USB port, which allows the user to load and flash new firmware
versions onto the device. The Kit can be purchased directly from Ainstein.
9.2. Additional Customizations
The US-D1 Radar Altimeter has several hardware and firmware customization options.
All customizations can be requested by contacting Ainstein directly.
Customizations
The following US-D1 hardware customizations can be requested prior to purchasing.
● US-D1 PCB (no enclosure)
● Interface Protocol (CAN, UART)
● Modified connector (JST, bare wire)
● Extended Cable (1 meter).
● BAUD Rate (38400, 57600, 115200, 250 Kbps, 500 Kbps, 1Mbps)
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10. Application Notes
Table 5 lists the application notes that will be addressed in future revisions.
Table 5: US-D1 Application Note
Issue ID
Description
Notes
1
If US-D1 is used outside of its Maximum
Operational Altitude (Table 1), Inconsistent
small readings will be output(See Figure 4
below).
● For full confidence,
only consider US-D1’s
data when used
within its operating
range
2
Altitude data from US-D1 may have various
step-size, since a post-processing algorithm is
implemented after radar processing, e.g.
averaging, filtering.
● No action needed
3
Altitude data from US-D1 may give
unexpected or incorrect measurements under
operation in an indoor environment. Multipath
reflections of the sensor’s radio waves are
complicated in enclosed environments and
may introduce errors in the radar’s processing.
● DO NOT rely on
US-D1 in an indoor,
tightly enclosed
environment
4
When the US-D1 is operated at altitudes of
~1m, there may be rare unstable readings
potentially due to multipath reflections of
reflective surroundings or inaccuracies due to
nearness to the radar’s blind zone.
5
When transitioning from normal detection to
out-of-range detection, the US-D1 will report
~0.51m when out-of-range, because 0.51m is
the edge of the US-D1’s blind zone.
6
When the US-D1 is close to the blind zone
(<1m) and a highly reflective object is placed in
between the US-D1 and the ground and then is
removed, the US-D1 output may get stuck
outputting erroneous values until another
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object enters the FOV.
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