Lacuna LS200 Sensor and Relay User Manual
- June 11, 2024
- Lacuna
Table of Contents
LS200 Sensor and Relay
Wireless satellite terminal with integrated circularly polarized
antenna system
DESCRIPTION
The LS200 Sensor and Relay has been designed for direct communication with the
Lacuna satellite network. The terminal is battery powered and is based around
a dual-core ARM M4/M0+ processor. The terminal contains a number of sensors, a
GNSS receiver and has an integrated Right Hand Circularly Polarized (RHCP)
satellite antenna, providing a 110° wide beam.
The terminal should be used outdoors and is contained in a protective
enclosure.
The terminal communicates with the satellite network in the SRD/ISM Band. It
can be ordered in two different SRD/ISM frequency band configurations: 862-870
MHz or 902-928 MHz.
APPLICATIONS
The primary applications of the terminal are direct communication of
(internal) sensor data to the satellite network and relay of data received
from third party LoRaWAN ® compatible sensors or devices.
As such the device is ideally suited for getting acquainted with the services
offered by the Lacuna satellite network. The device may also be used as a
reference design for third parties wishing to develop their custom designs.
FEATURES
- 862-870 MHz or 902-928 MHz RHCP antenna
- GNSS RHCP antenna
- 84 x 84 x 20 (mm) without casing
- 94 x 94 x 45 (mm) with casing
APPLICATIONS
- Satellite communication
- Low power wireless relay
- LPWAN device
TECHNICAL SUPPORT
Lacuna Space Ltd.
R104 Rutherford Appleton
Laboratory
Harwell Campus
Didcot England
OX11 0QX
support@lacuna.space
Part numbers
LS200-XXX-A Where: -XXX refers to frequency option: 868 for 862-870 MHz, 915
for 902-928 MHz
Warning: The use of certified protected batteries is mandatory
| Part Number | Freq (MHz) | Battery holder |
|---|---|---|
| LS200-868-A | 868 | 3 x AA alkaline battery holder |
| LS200-915-A | 915 | 3 x AA alkaline battery holder |
General Data
| Parameter | Value | Comments |
|---|---|---|
| Operating temperature | -20°C to 55°C | |
| Characteristic Impedance | 50 ohm | |
| Weight | 215 gram | Including casing, excluding batteries |
| Dimensions (Board) | 848420 (mm) | Battery holder not considered |
| Dimensions (Casing) | 949445 (mm) | Includes casing and battery holder |
| Battery | 3 AA alkaline | |
| Mounting holes | M3 |
RF Characteristics
| Parameter | 868/915 band | GNSS |
|---|---|---|
| Frequency Range (MHz) | 862-870 | 902-928 |
| Typical Frequency (MHz) | 870 | 915 |
| Peak Total Gain (dBi) ** | 1.69 | 1.75 |
| Peak RHCP Gain (dBic) ** | 1.49 | 1.62 |
| Average Gain (dBi) ** | -2.3 | -2.2 |
| Total Efficiency (max) | 49% | 50% |
| Axial Ratio (dB) | < 6 | < 6 |
| Reflection coefficient (dB) | < -10 | < -10 |
| Peak EIRP (dBm) *** | 23.69 | 23.75 |
- Model variant 868: LS200-868-A, Model variant 915: LS200-915-A
** Values for “Typical Frequency”
*** Hardware maximum. Transmissions will be limited in software according to regional regulations.
Main components
Traditional satellite terminal solutions often are comprised of several macro
components, e.g. power supply, modem, amplifiers, splitters, antennas, that
are interconnected with coaxial cables. With the LS200 Sensor and Relay
terminal all these components are integrated onto a single printed circuit
board resulting in a much smaller and power efficient device. All components
listed in the table below are surface-mounted, integrated chips that cannot be
removed or replaced without damage to the electronics board. The components
cannot be used as stand-alone modules.
| Description | MPN | Manufacturer |
|---|
Ultra-low-power dual core Arm Cortex-M4 MCU 64 MHz, Cortex-M0+ 32 MHz with 512
Kbytes of Flash memory, Bluetooth LE 5.2, 802.15.4, Zigbee, Thread, USB, LCD,
AES-256| STM32WB55RE| STMicroelectronics
LR1120 Low Power Wi-Fi/ GNSS Scanner + LoRa® Transceiver| LR1120| Semtech
Quectel LC76F Compact GNSS Module, concurrent reception of GPS, GLONASS,
BeiDou and QZSS| LC76F| Becquerel
Tri-axis digital accelerometer sensor ± 2g / 4g / 8g| KX023-1025-FR| Kionix
Digital humidity, pressure and temperature sensor -40…+85C, 0…100% RH,
300…1100 hPa| BME280| Bosch Sensortec
Digital-switch hall effect sensor 6.9 / 3.2 mT| DRV5023AJQLPGM| Texas
Instruments
Fully Integrated Li-Ion, Li-Polymer Charge Management Controller| MCP73831T-
2ATI/OT| Microchip Technology
Block diagram
The block diagram below shows how the main components are interconnected on
the printed circuit board. All antennas are integral part of the LS200 Sensor
and Relay device and cannot be removed or replaced. The elements of the RF
chain are included in the circuitry as follows:
- 862-870 MHz/ 902-928 MHz RCHP: All elements integrated in LR1120 chip
- 1.575 GHz GNSS: All elements integrated in LC76F chip
Terminal dimensions
Casing
The casing includes a vent on the bottom. The vent can be replaced by a cable
gland to connect external sensors.
The top cover is fixed to the bottom part using M3 screws. The casing is made
from white ABS material. It has passed both UL50E and IP67 testing.
LS200 Sensor and Relay
1.1 Introduction
The LS200 Sensor and Relay is intended to give users hands-on experience with
the Lacuna satellite network. The device supports several different
operational modes allowing it to be used as a stand-alone satellite terminal
or as a satellite relay. In relay mode the device forwards data received from
standard LoRaWAN ® sensors to the Lacuna satellite network.
The device can also be used as a reference design for device manufacturers to
create or adapt their own hardware and software for operation with the Lacuna
satellite network.
Lacuna encourages vendors and end users to build their own sensor hardware and
software. It is however recommended to first get started with the LS200 Sensor
and Relay and the standard operational modes provided. This will help
accelerate through initial proof-of-concept trials, familiarizing the user
with the specifics of the Lacuna space network and give a good start for
further exploration.
1.2 Description
The LS200 Sensor and Relay is shown below and is built around a STM32WB55 MCU
and a Semtech LoRa Edge™ LR1120 transceiver. The device is battery powered and
can run autonomously for prolonged periods. Battery lifetime is dependent on
the configuration and transmission intervals.
The device contains the following sensors and peripherals:
- GNSS module (Quectel LC76F)
- Tri-axis accelerometer (Kionix KX023-1025-FR)
- Combined pressure, temperature and humidity sensor (Bosch Sensortec BME280)
- Hall-effect sensor (Texas Instruments DRV5023AJ)
1.3 LS200 operational modes
The main operational modes of the LS200 Sensor and Relay are:
- Sensor
- Relay
- Program
In both sensor and relay modes the device runs the pre-installed Lacuna
software. The pre-installed software enables the user to configure the device
through a USB cable and serial console software. In sensor mode the device
runs standalone. It automatically makes contact with the Lacuna satellite
network and transmits the values of its internal sensors. The user can
configure parameters including region, LoRaWAN ® security keys, transmission
interval and which sensor data is to be transmitted. The user can also query
the device for information such as the next available satellite pass and the
date and time of the last transmission.
In relay mode the device operates as a receiver for compatible 3rd party
LoRaWAN ® sensors, stores the data and transmits the data to the Lacuna
satellite network at the first opportunity. The user can configure parameters
including receive interval, device IDs of the 3rd party sensors, and the
priority rules for forwarding from multiple sensors. The relay mode is very
convenient for operating the device in remote regions where no terrestrial
network coverage is available or to assist with deep indoor or below
ground penetration.
The program mode is intended for developers wishing to extend the device
functionality. Lacuna Space provides a standard software library abstracting
all specifics of the Lacuna satellite network operation including calculation
of the next available satellite pass and configuration of the radio front-end
for satellite transmission. The standard software library ensures that the
device always operates within the limits for the region that is configured by
the user.
Regardless of the operational mode, upon first use the device must be
configured by the user for operation in a specific region. If the device is
not configured for a specific region radio transmissions are disabled. The
information on regional specifications, e.g. available frequency band, maximum
transmit power, duty cycle and dwell time (where applicable) is included in
the Lacuna supplied software.
NOTE: certification is only valid for sensor and relay modes with Lacuna
supplied software. In program mode it is the responsibility of the developer
to use the Lacuna supplied software library to ensure operation within local
regulatory limits. Using program mode may require re-certification of the
device.
1.4 LS200 setup and installation
Before the first use, batteries must be inserted into the device. This can be
done by opening the casing with the supplied Allen key. Three standard AA
Alkaline batteries should be used. Please check the correct polarity when
inserting the batteries.
After the batteries are placed the device should be configured by using the
supplied a USB cable. Details on how to configure the device through a serial
console can be found here: https://lacuna.space/LS200 After the device
is configured the casing can be closed again. Make sure the gaskets fit snugly
when screwing the case shut, to prevent any moisture from entering the case.
The device should now be placed outside, preferably at an elevated surface at
least 15 cm above the ground (or roof). The device should have a clear line of
sight to the sky and no obstructions should be nearby (in a cone of 45 degrees
around the device). The device should now automatically start making contact
with the Lacuna Satellite network.
The interval of transmissions is dependant on the exact configuration of the
device and network coverage in the region of use.
Please note that the Hall-effect sensor might give inaccurate readings when it
is used near strong magnetic fields/ mains lines.
Lacuna system overview
2.1 Introduction
This chapter describes the key concepts of the operation of the Lacuna
satellite network. This will help improve understanding of the key
opportunities and applications of the technology. As mentioned before, the
provided software (libraries) and tools will abstract most of the specifics of
using satellite communications.
2.2 Satellite network
The Lacuna satellite network makes use of both Low Earth Orbit (LEO)
satellites as well as Medium Earth Orbit (MEO) satellites. The LEO satellites
operate at an altitude of 500-550 km above the surface of the Earth in an
orbit that runs (nearly) over the North and South poles (polar orbit). Some
satellites might orbit at lower inclinations, offering shorter revisit times
for lower latitudes. The LEO satellites operate in the SRD/ISM band (862-870
MHz or 902-928 MHz depending on the region). Each LEO satellite orbits the
Earth in about 100 minutes which equates to about 15 orbits per day. As the
Earth rotates beneath the orbits of the satellites, the antenna beam
eventually scans the whole of the globe’s surface. A given location would be
in contact with each satellite 1-2 times per day with a contact window of 2-4
minutes for each pass.
MEO
satellites are not supported by LS200, as it does not include S-Band
capabilities. However, to provide the full picture, the working principle of
the MEO satellites is described below. MEO satellites operate at approximately
10,000 km altitude, resulting in a slower orbit rate of 3-4 orbits per day,
inclined by 45 degrees so that a given location would be in contact with the
satellites 2 times a day with an extended contact window of up to 2 hours for
each pass. Each satellite has 163 spot beams covering around 17% of the Earth
at any time. The MEO satellites operate in the MSS S-Band frequency range
(1980-2010 MHz uplink, 2170-2200 MHz downlink).
Although the revisit times and the frequencies used by the LEO and the MEO
satellites differ, the same modulation and low-power chipset are used for
communication. The end user does not have to be aware which satellite is used
in which region, the LS200 Sensor and Relay abstracts all communications with
the network. The embedded application sends a message which is automatically
forwarded to the satellite network at the earliest opportunity, regardless of
the type of satellite.
2.3 Principle of operation
A simplified diagram of the principle of operation is shown in figure 4.
In the figure the LEO satellite travels from left to right with a speed of
about 7.5 km per second. At a certain time, the sensor device (purple box)
will be inside the footprint of the satellite, creating a contact window. As
soon as this is the case the device can start its transmission. When the
satellite receives the data sent from the device, it temporarily stores the
data and the satellite continues in its orbit. MEO satellites operate at
higher altitude with a slower orbit rate and wider beam footprint, but the
working principle is the same.
When the satellite subsequently passes a ground station, the satellite then
downloads the stored data to the ground station, which in turn forwards it to
the Lacuna router hub, and then to the customer’s account in a LoRa Network
Server (LNS). All data transmitted by the device nodes is encrypted end-toend,
this means that neither Lacuna Space nor any party in the chain is able to
decode the contents of what is transmitted. Only the end user can decode the
data.
The latency between the transmission of data from the sensor device and
reception at the customer’s server account is determined by the relative
position of the sensor device in relation to the ground station(s) as well as
the type of satellite in view (LEO or MEO). The further the satellite must
travel before it passes a ground station, the higher the latency will be. In
specific regions a MEO satellite may be in view of both the sensor device and
a ground station, providing a real-time (zero latency) connection.
The device nodes are only allowed to transmit with very limited power in the
frequency bands used. The LS200 Sensor and Relay is fitted with a polarized
antenna with upwards directional gain. This design gives the device optimum
performance even at very low elevation angles (down to 20 degrees). It is up
to the user to further optimize the conditions by optimal placement of the
device. For example, a device can best be placed at least 15 cm from the
ground in a position free from nearby obstructions (e.g. tree canopy), with a
clear line of sight to the sky.
Compliance
3.1 FCC compliance
FCC ID: 2A8AP-LS300
This device complies with FCC 47 CFR Part 15 and Part 25 Subpart C regulations
for radio devices.
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.
Changes or modifications not expressly approved by the party responsible for
compliance could void the user’s authority to operate the equipment.
The device has been tested and found to comply with the limits for a Class B
digital device, pursuant to Part 15 of the FCC rules. These limits are
designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses and can radiate radio
frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications. However,
there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the equipment off and
on, the user is encouraged to try to correct the interference by one or more
of the following measures:
- Reorient or relocate the receiving antenna.
- Increase the separation between the equipment and receiver.
- Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.
The device must not be co-located or operating in conjunction with any other
antenna or transmitter.
This statement is based on the FCC regulations in effect on Feb 8th 2023. The
manufacturer assumes no responsibility for any errors or omissions in this
statement. The user shall not make any changes or modifications to the device
unless authorized by the manufacturer. Unauthorized changes or modifications
could void the user’s authority to operate the device.
Lacuna Space Ltd.
R104 Rutherford Appleton LaboratoryHarwell Campus
Didcot England
OX11 0QX
support@lacuna.space
For contact and product information, visit https://lacuna.space
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equipment.
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©2023 Lacuna Space Ltd. All rights reserved.
References
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