EP4324118A1

EP4324118A1 - Communications gateway unit, remotely piloted aircraft, and methods

Info

Publication number: EP4324118A1
Application number: EP22724472.0A
Authority: EP
Inventors: Robert Bowyer; Charles TAVNER; Ed CLAY; Richard Nicholson; Mike PERRETT; Chris Adams
Original assignee: Flylogix Ltd
Current assignee: FLYLOGIX HOLDINGS LIMITED
Priority date: 2021-04-12
Filing date: 2022-04-12
Publication date: 2024-02-21
Also published as: GB202105174D0; WO2022219325A1

Abstract

There is disclosed a communications gateway unit, the communications gateway unit including at least a satellite communications transceiver, a first cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver and a second cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver. An advantage is that the communications gateway unit can be used to provide very reliable command & control for a vehicle including the communications gateway unit, where the vehicle may be a Remotely Piloted Aircraft (RPA), an aircraft, a land vehicle, or a marine vehicle.

Description

COMMUNICATIONS GATEWAY UNIT, REMOTELY PILOTED AIRCRAFT, AND METHODS

BACKGROUND OF THE INVENTION

1. Field of the Invention

The field of the invention relates to communications gateway units, to vehicles which include communications gateway units, an example vehicle being a remotely piloted aircraft, and to related methods.

2. Technical Background

Effective beyond visual line of sight command and control systems typically require low-latency communications links, and existing systems tend to be proprietary and/or military based and thus are expensive and not generally applicable for commercial use due to use of restricted radio frequency (RF) licensed bands and/or RF power being above legislated levels. Therefore there is a need for a flight control system, including a Remotely Piloted Aircraft (RPA) and a ground-based control centre, which overcomes some or all of these problems. There is also a need for components of a flight control system, including a Remotely Piloted Aircraft (RPA) and a ground- based control centre, which overcome some or all of these problems.

A portion of the disclosure of this patent document contains material, which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

3. Discussion of Related Art

W02019058116A1 discloses a method of, or a system for, controlling a pilotless device, which uses independent data links that provide multiple, redundant data channels. First, a direct radio link with a ground control station is used to receive command signals that enable a pilot to issue commands to an autopilot in the device, or to directly control the device. Secondly, there is an indirect control link with the ground control station, via satellites, that is used to send command signals to the device and to send back flight information and position data from a GPS or other satellite-based position receiver in the device. Thirdly, there is an indirect position data link back to the ground control station, via low earth orbit satellites, that is used to send back position data from a different GPS or other satellite-based position receiver in the device. W02019058116A1 is incorporated by reference.

PCT application PCT/GB2020/052643 is incorporated by reference.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a communications gateway unit, the communications gateway unit including at least a satellite communications transceiver, a first cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver and a second cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver. An advantage is that the communications gateway unit can be used to provide very reliable command & control for a vehicle including the communications gateway unit, where the vehicle may be a RPA, an unmanned aircraft, an aircraft, a land vehicle, or a marine vehicle, or a waterborne vehicle. An advantage is that communications hardware of a vehicle including the communications hardware can be rapidly replaced by exchanging the unit. An advantage is that an RPA including the unit can be controlled very safely without direct involvement of air traffic control.

The communications gateway unit may be one wherein the satellite communications transceiver, the first cellular transceiver and the second cellular transceiver are configured for use for bi-directional data communications.

The communications gateway unit may be one wherein the communications gateway unit is arranged such that the first cellular transceiver (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) and the second cellular transceiver (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) are configured to use different cellular networks. An advantage is that the communications gateway unit can be used to provide very reliable command & control for a vehicle including the communications gateway unit.

The communications gateway unit may be one wherein the first cellular transceiver is a 4G cellular transceiver. Advantages include providing a long range and a high data rate.

The communications gateway unit may be one wherein the first cellular transceiver is a LoRa gateway transceiver. A LoRa gateway transceiver may be a LoRa gateway card to allow meshing of multiple RPAs. The communications gateway unit may be one wherein the second cellular transceiver is a 4G cellular transceiver. Advantages include providing a long range and a high data rate.

The communications gateway unit may be one wherein the first cellular (e.g. a non roaming) transceiver is configured to communicate with a network that is an inshore network. An advantage is that the communications gateway unit can be used to provide very reliable command & control for a vehicle including the communications gateway unit, near to a coast.

The communications gateway unit may be one wherein the second cellular (e.g. a roaming) transceiver is configured to communicate with a cellular network that is not an inshore network.

The communications gateway unit may be one wherein the first cellular transceiver is a non-roaming transceiver, and the second cellular transceiver is a roaming transceiver. An advantage is that the communications gateway unit can be used to provide very reliable command & control for a vehicle including the communications gateway unit.

The communications gateway unit may be one wherein the satellite transceiver includes an antenna and a roll gimbal (e.g. with tuned damping) to ensure that the antenna is level and thus has good connection when banking. An advantage is that the communications gateway unit can be used to provide very reliable command & control for a vehicle including the communications gateway unit.

The communications gateway unit may be one wherein the communications gateway unit is configured to provide a satellite communications link to a server, and at least one cellular communications link to the server, using the first cellular transceiver or using the second cellular transceiver. An advantage is that the communications gateway unit can be used to provide very reliable command & control for a vehicle including the communications gateway unit. The communications gateway unit may be one wherein the communications gateway unit is configured to provide a satellite communications link to a server, and at least two cellular communications links to the server, using the first cellular transceiver and using the second cellular transceiver. An advantage is that the communications gateway unit can be used to provide very reliable command & control for a vehicle including the communications gateway unit.

The communications gateway unit may be one wherein the server is a mission control server.

The communications gateway unit may be one receiving positional data from an autopilot, wherein the autopilot is configured to determine a position of the communications gateway unit using a GPS antenna, and to store the determined position of the communications gateway unit in a storage medium of the communications gateway unit. An advantage is that the communications gateway unit can be used to provide very reliable command & control for a vehicle including the communications gateway unit.

The communications gateway unit may be one wherein the communications gateway unit is configured to transmit a determined position of the communications gateway unit to a server.

The communications gateway unit may be one wherein each transceiver is operable to provide a communication link, wherein the communications gateway unit is configured to choose and/or to determine an appropriate communication link to use to send data.

The communications gateway unit may be one wherein the communications gateway unit is configured to use a multi-objective cost function to determine an appropriate link to send data over.

The communications gateway unit may be one wherein the cost function is or includes Route(t) = arg min{ J SatComms, J First cellular, J Second cellular }, subject to the latency < critical time, where J_{xx} = cost per data throughput.

The communications gateway unit may be one wherein each transceiver is operable to provide a communication link, wherein the communications gateway unit is configured to store telemetry data.

The communications gateway unit may be one wherein the telemetry data stored on the communications gateway unit includes one or more of: position, GPS data, altitude, acceleration, pressure, gas sensor (e.g. methane) data.

The communications gateway unit may be one including a serial port or a USB port.

The communications gateway unit may be one configured to output telemetry data stored on the communications gateway unit via an interface of the communications gateway unit e.g. a serial port or a USB port.

The communications gateway unit may be one configured to receive operational commands from a computer in communication with the communications gateway unit, such as being in communication with the communications gateway unit using the satellite transceiver, or using the first cellular transceiver or using the second cellular transceiver, such as being in internet communication with the communications gateway unit using the satellite transceiver, or using the first cellular transceiver or using the second cellular transceiver.

The communications gateway unit may be one suitable for a Remotely Piloted Aircraft (RPA).

The communications gateway unit may be one wherein the communications gateway unit is cuboid shaped.

The communications gateway unit may be one wherein the communications gateway unit has dimensions between 10 cm by 6 cm by 4 cm , and 20 cm by 15 cm by 8 cm. The communications gateway unit may be one wherein the communications gateway unit has a volume in the range 300 cm³ to 1200 cm³, and/or a mass in the range of 400 g to 1000 g, and/or operates in a power range between 2 W and 20 W.

The communications gateway unit may be one wherein the communications gateway unit includes a WiFi transceiver.

The communications gateway unit may be one wherein the communications gateway includes more than two cellular transceivers, for example where each cellular transceiver uses a different network provider.

The communications gateway unit may be one wherein the communications gateway is configured to manage one or more of, or all of, a command and control link, a Sensor link, a RoIP link, a Video link.

According to a second aspect of the invention, there is provided a Remotely Piloted Aircraft (RPA) including a body and a communications gateway unit of any aspect of the first aspect of the invention. An advantage is that the communications gateway unit can be used to provide very reliable command & control for the RPA.

The RPA may be one wherein the communications gateway unit is installable into, and removable from, the body of the RPA. An advantage is rapid replacement of communications hardware of the RPA.

The RPA may be one wherein the communications gateway unit is installed inside a wing of the RPA. An advantage is improved reception and transmission for the communications hardware of the RPA.

The RPA may be one wherein the RPA is configured to receive primary command and control commands for the RPA via the satellite transceiver. An advantage is that the communications gateway unit can be used to provide very reliable command & control for the RPA. The RPA may be one wherein the RPA is configured to receive primary command and control commands for the RPA via the first cellular transceiver or via the second cellular transceiver. An advantage is that the communications gateway unit can be used to provide very reliable command & control for the RPA.

The RPA may be one wherein the communications gateway unit is switchable to receive primary command and control commands for the RPA from via the satellite transceiver, to via the first cellular transceiver or the second cellular transceiver. An advantage is that the communications gateway unit can be used to provide very reliable command & control for the RPA.

The RPA may be one wherein the communications gateway unit is switchable to receive primary command and control commands for the RPA via the first cellular transceiver or the second cellular transceiver, to via the satellite transceiver. An advantage is that the communications gateway unit can be used to provide very reliable command & control for the RPA.

The RPA may be one wherein the switching occurs seamlessly. An advantage is providing very reliable command & control for the RPA.

The RPA may be one wherein the RPA includes a UHF transceiver.

The RPA may be one wherein the UHF transceiver is configured to communicate telemetry data.

The RPA may be one wherein the UHF transceiver is configured to receive a response to transmitted telemetry data.

The RPA may be one wherein the RPA is configured to provide RoIP or VoIP communications, using the satellite transceiver, or using the first cellular transceiver or using the second cellular transceiver. An advantage is providing very reliable command & control for the RPA. The RPA may be one wherein the RPA includes a Light Detection and Ranging (LIDAR) measurement system arranged to measure the distance above the ground or water of the RPA when in flight. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the RPA is configured such that the distance above ground or water measured using the LIDAR measurement system is compared with a GPS position, possibly supplemented by barometric pressure, to confirm that the distance above ground or water measured using the LIDAR measurement system is accurate. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the RPA is configured to determine a difference between the LIDAR measurements of the distance above the ground or water of the RPA when in flight and the distance above the ground or water of the RPA when in flight estimated using GPS and/or barometric pressure. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the RPA is configured to automatically recalibrate the distance above the ground or water of the RPA when in flight estimated using GPS and/or barometric pressure, using the determined difference. An advantage is improved safety of operation of the RPA.

The RPA may be one configured to automatically recalibrate the distance above the ground or water of the RPA when in flight measured using LIDAR, using the determined difference. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the RPA includes a video camera. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the video camera is a nighttime camera e.g. an infra red sensitive camera. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the video camera is configured to record video at a higher rate during take off and/or landing, and to record video at a lower rate at other times e.g. when flying over water. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the RPA includes a transceiver for automatic dependent surveillance-broadcast (ADS-B), e.g. wherein the RPA is configured to provide collision avoidance. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the RPA is configured to communicate with a Local Ground Station (LGS).

The RPA may be one wherein the RPA is configured to receive flight control commands from a pilot located at a Mission Control centre via the LGS. An advantage is improved safety of operation of the RPA.

The RPA may be one including a stored a flight plan, wherein the RPA includes a processor configured to execute a (e.g. real-time) fuel estimation algorithm that uses the present position and calculates the fuel that is estimated to remain upon completion of the flight plan, and communicates an alert to a pilot if the RPA needs to return to base before completing the flight plan in order to return with a set amount of fuel reserve. An advantage is improved safety of operation of the RPA.

The RPA may be one including sensors, in which sensors can be turned off during flight; and/or wherein the RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

The RPA may be one wherein the communications gateway manages one or more of, or all of, a command and control link, a Sensor link, a RoIP link, a Video link.

The RPA may be one including an autopilot, wherein the communications gateway transmits position data computed by the autopilot.

According to a third aspect of the invention, there is provided a Remotely Piloted Aircraft (RPA) including at least a satellite communications transceiver, a first cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver and a second cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver. An advantage is that the RPA may be controlled very reliably.

The RPA may be one wherein the first cellular transceiver (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) and the second cellular transceiver (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) are configured to use different cellular networks. An advantage is that the RPA may be controlled very reliably.

The RPA may be one wherein the first cellular (e.g. a non-roaming) transceiver is configured to communicate with a network that is an inshore network. An advantage is that the RPA may be controlled very reliably near to a coast.

The RPA may be one wherein the second cellular (e.g. a roaming) transceiver is configured to communicate with a cellular network that is not an inshore network.

The RPA may be one wherein the first cellular transceiver is a non-roaming transceiver, and the second cellular transceiver is a roaming transceiver. An advantage is that the RPA may be controlled very reliably.

The RPA may be one configured to provide a satellite communications link to a server, and at least one cellular communications link to the server, using the first cellular transceiver or using the second cellular transceiver. An advantage is that the RPA may be controlled very reliably.

The RPA may be one configured to provide a satellite communications link to a server, and at least two cellular communications links to the server, using the first cellular transceiver and using the second cellular transceiver. An advantage is that the RPA may be controlled very reliably.

The RPA may be one configured to receive primary command and control commands for the RPA via the satellite transceiver. An advantage is that the RPA may be controlled very reliably.

The RPA may be one configured to receive primary command and control commands for the RPA via the first cellular transceiver or via the second cellular transceiver. An advantage is that the RPA may be controlled very reliably.

The RPA may be one switchable to receive primary command and control commands for the RPA from via the satellite transceiver, to via the first cellular transceiver or the second cellular transceiver. An advantage is that the RPA may be controlled very reliably.

The RPA may be one switchable to receive primary command and control commands for the RPA from via the first cellular transceiver or the second cellular transceiver, to via the satellite transceiver. An advantage is that the RPA may be controlled very reliably.

The RPA may be one wherein the switching occurs seamlessly.

The RPA may be one wherein the RPA is configured to provide RoIP or VoIP communications, using the satellite transceiver, or using the first cellular transceiver or using the second cellular transceiver. An advantage is that the RPA may be controlled very reliably.

The RPA may be one wherein the RPA includes a Light Detection and Ranging (LIDAR) measurement system arranged to measure the distance above the ground or water of the RPA when in flight. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the video camera is a nighttime camera e.g. an infra red sensitive camera. An advantage is improved safety of operation of the RPA. The RPA may be one wherein the RPA is configured to communicate with a Local Ground Station (LGS).

The RPA may be one including a stored a flight plan, wherein the RPA includes a processor configured to execute a (e.g. real-time) fuel estimation algorithm that uses the present position and calculates the fuel that is estimated to remain upon completion of the flight plan, and communicates an alert to a pilot if the RPA needs to return to base before completing the flight plan in order to return with a set amount of fuel reserve; and/or wherein the RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the RPA includes respective apparatus and is configured to provide a respective function of the communications gateway unit of any aspect of the first aspect of the invention.

According to a fourth aspect of the invention, there is provided a RPA, the RPA including a transceiver and a remaining fuel measurement device arranged to measure the (e.g. aviation) fuel remaining, the RPA configured to determine the present position, the RPA including a stored flight plan, wherein the RPA includes a processor configured to execute a (e.g. real-time) fuel estimation algorithm that uses the present position and the measured remaining fuel, and calculates the fuel that is estimated to remain upon completion of the flight plan, and communicates an alert to a pilot using the transceiver if the RPA needs to return to base before completing the flight plan in order to return with a set amount of fuel reserve. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the algorithm uses a purely geometric calculation of the remaining flight path. An advantage is improved safety of operation of the RPA. The RPA may be one wherein the algorithm uses the current aircraft position and the waypoints remaining in the flight plan and calculates the approximate path that the RPA will take. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the approximate path is calculated as a series of segments which are straight lines or circular arcs. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the algorithm uses the known velocity of the aircraft in still air, the wind speed and direction. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the wind speed and direction are received via the transceiver. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the algorithm calculates the range of fuel that will remain at the end of the flight plan based on a range of wind scenarios. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the range of wind scenarios are received via the transceiver.

The RPA may be one wherein if any of the range of fuel that will remain on landing falls below a predefined threshold, the mission is automatically aborted, or curtailed, to avoid running out of fuel during the mission. An advantage is improved safety of operation of the RPA.

The RPA may be one wherein the calculated fuel use is the fuel bum rate multiplied by the calculated total remaining flight time.

The RPA may be one wherein the RPA is an RPA of any aspect of the second or third aspects of the invention; and/or wherein the RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

According to a fifth aspect of the invention, there is provided a method of relaying data between a first RPA and a second RPA, the first RPA including a first satellite communications transceiver, and a first non-satellite communications transceiver, the second RPA including a second satellite communications transceiver, and a second non-satellite communications transceiver, wherein the first RPA and the second RPA are airborne, and are in sufficient proximity to communicate using the first non satellite communications transceiver and the second non-satellite communications transceiver, the method including the step that if the first satellite communications transceiver of the first RPA malfunctions and if the second satellite transceiver is operational, then the first RPA and the second RPA communicate via the first non satellite communications transceiver and the second non-satellite communications transceiver, the first RPA sending a communication to the second RPA that the first satellite communications transceiver of the first RPA has malfunctioned, the second RPA relaying this communication to a mission control centre using the second satellite communications transceiver. An advantage is improved safety of operation of the RPAs.

The method may be one wherein the first non-satellite communications transceiver and the second non-satellite communications transceiver are both WiFi transceivers, or are both 868 MHz radio transceivers, or are both LoRa transceivers.

The method may be one wherein the second RPA receives instructions using the second satellite communications transceiver from the mission control centre for the first RPA to guide the first RPA back to base, and the second RPA sending those received instructions to the first RPA using the first non-satellite communications transceiver and the second non-satellite communications transceiver. An advantage is improved safety of operation of the RPAs.

The method may be one wherein the second RPA continues to receive instructions using the second satellite communications transceiver from the mission control centre for the first RPA to guide the first RPA back to base, and the second RPA sending those received instructions to the first RPA using the first non-satellite communications transceiver and the second non-satellite communications transceiver, until the first RPA arrives back at base, or until the first RPA is in range of a cellular network through which the first RPA communicates with the mission control centre using a cellular transceiver of the first RPA. An advantage is improved safety of operation of the RPAs.

The method may be one wherein the first RPA includes a transponder, wherein a "communications lost" emergency squawk code is not transmitted by the transponder. An advantage is not disrupting air traffic.

The method may be one wherein the first RPA is a RPA of any aspect of the second or third aspects of the invention, and/or wherein the second RPA is a RPA of any aspect of the second or third aspects of the invention; and/or wherein the first RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m; and/or wherein the second RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

According to a sixth aspect of the invention, there is provided a method of relaying data between a first RPA and a second RPA, the first RPA including a first satellite communications transceiver, a first cellular transceiver and a first non-satellite communications transceiver, the second RPA including a second satellite communications transceiver, a second cellular transceiver and a second non-satellite communications transceiver, wherein the first RPA and the second RPA are airborne, and are in sufficient proximity to communicate using the first non-satellite communications transceiver and the second non-satellite communications transceiver, the method including the step that if the second cellular communications transceiver of the second RPA is out of range of a cell tower and first cellular communications transceiver of the first RPA is in range of a cell tower, then the first RPA and the second RPA communicate via the first non-satellite communications transceiver and the second non-satellite communications transceiver, in which the second RPA sends data to the first RPA, the first RPA relaying this data to a mission control centre using the first cellular communications transceiver. The method may be one wherein the first non-satellite communications transceiver and the second non-satellite communications transceiver are both WiFi transceivers, or are both 868 MHz radio transceivers, or are both LoRa transceivers.

The method may be one wherein route plans are prepared and stored on each RPA to make sure at least one RPA has cellular coverage to send high rate (e.g. 4G) data back to the mission control centre from both RPAs.

According to a seventh aspect of the invention, there is provided a RPA including a plurality of transceivers and a transponder, the RPA configured such that if communication via all the transceivers is not available for a specified length of time (e.g. 15 seconds), the RPA broadcasts in response a Mode S emergency squawk code using the transponder. An advantage is improved safety of operation of the RPAs.

The RPA may be one wherein the RPA is a RPA of any aspect of the second or third aspects of the invention.

According to an eighth aspect of the invention, there is provided a method of identifying a source of emissions, the method including the steps of:

(i) a RPA flying around a target, the RPA including a gas sensor, the RPA including a position determining apparatus, the RPA recording gas sensor readings and the corresponding positions of the RPA, the RPA storing the recorded gas sensor readings and the recorded corresponding positions of the RPA;

(ii) analyzing the stored recorded gas sensor readings and the corresponding positions of the RPA such that positions at which a local maximum gas sensor reading is obtained are identified;

(iii) projecting a line through the positions at which a local maximum gas sensor reading was obtained towards a region of the target, to identify a source of the emissions in the region of the target. An advantage is precisely locating a source of the emissions in the region of the target.

The method may be one including the step of: (iv) storing the identified source of the emissions in the region of the target. The method may be one wherein the line in step (iii) is a straight line. An advantage is precisely locating a source of the emissions in the region of the target.

The method may be one wherein the line in step (iii) is not a straight line, e.g. a polynomial fit, of order two (i.e. a quadratic) or of order greater than two. An advantage is precisely locating a source of the emissions in the region of the target.

The method may be one wherein the line is a best fit in a statistical analysis e.g. a regression analysis, which optionally includes wind speed and direction. An advantage is precisely locating a source of the emissions in the region of the target.

The method may be one wherein step (iii) includes performing a 3D Computational Fluid Dynamics (CFD) diffusion computation, for example including using estimates of the wind field and target shape, or wherein step (iii) is instead performing a 3D Computational Fluid Dynamics (CFD) diffusion computation, for example including using estimates of the wind field and target shape, to identify a source of the emissions in the region of the target. An advantage is precisely locating a source of the emissions in the region of the target.

The method may include the RPA flying around the target in a horizontal plane. An advantage is precisely locating a source of the emissions in the region of the target.

The method may include the RPA flying around the target in circles of different radii. An advantage is precisely locating a source of the emissions in the region of the target.

The method may include the RPA flying around the target in a vertical plane. An advantage is precisely locating a source of the emissions in the region of the target.

The method may include the RPA flying around the target in circle portions (e.g. semicircles) of different radii. An advantage is precisely locating a source of the emissions in the region of the target. The method may include the RPA flying around the target in three dimensions. An advantage is precisely locating a source of the emissions in the region of the target.

The method may include the RPA not flying in circular paths.

The method may be one in which the RPA includes a transceiver, the RPA using the transceiver to transmit the stored recorded gas sensor readings and the corresponding positions of the RPA to a computer, the computer receiving the transmitted stored recorded gas sensor readings and the corresponding positions of the RPA, and the computer performing the analysis of steps (ii) and (iii). An advantage is precisely locating a source of the emissions in the region of the target.

The method may be one wherein the gas sensor is a methane sensor.

The method may be one wherein the gas sensor senses fluorinated gases, or hydrofluorocarbons (HFCs), or perfluorocarbons (PFCs), or sulphur hexafluoride (SF6) or nitrogen trifluoride (NF3), or NOx or SOx, or C02.

The method may be one wherein the RPA includes a plurality of gas sensors, and the method includes recording gas sensor readings and the corresponding positions of the RPA for the plurality of gas sensors, the RPA storing the recorded gas sensor readings and the corresponding positions of the RPA for the plurality of gas sensors, and performing steps (ii) and (iii) for respective stored gas sensor readings. An advantage is the ability to identify the type of leak.

The method may be one wherein the detection of different gases is used to identify the type of leak or emissions.

The method may be one wherein the RPA is a RPA of any aspect of the second or third aspects of the invention; and/or wherein the RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

According to a ninth aspect of the invention, there is provided a method of identifying a source of emissions, the method including the steps of:

(i) a RPA flying around or near to a target, the RPA including a gas sensor, the RPA including a position determining apparatus, the RPA recording gas sensor readings and the corresponding positions of the RPA, the RPA storing the recorded gas sensor readings and the recorded corresponding positions of the RPA;

(ii) analyzing the stored recorded gas sensor readings and the corresponding positions of the RPA such that a position at which a local maximum gas sensor reading is obtained is identified;

(iii) projecting a line through the position at which a local maximum gas sensor reading was obtained towards a region of the target, and using the wind speed and direction, to identify a source of the emissions in the region of the target. An advantage is that a source of the emissions may be identified with a single flyby of the target.

The method may be one including the step of: (iv) storing the identified source of the emissions in the region of the target.

The method may be one wherein the line in step (iii) is a straight line.

The method may be one wherein step (iii) includes performing a 3D Computational Fluid Dynamics (CFD) diffusion computation, for example including using estimates of the wind field and target shape, or wherein step (iii) is instead performing a 3D Computational Fluid Dynamics (CFD) diffusion computation, for example including using estimates of the wind field and target shape, to identify a source of the emissions in the region of the target.

The method may be one including the RPA flying around the target in a horizontal plane.

The method may be one including the RPA flying around the target in a vertical plane.

The method may be one including the RPA flying around the target in three dimensions. The method may be one including the RPA not flying in circular paths.

The method may be one in. which the RPA includes a transceiver, the RPA using the transceiver to transmit the stored recorded gas sensor readings and the corresponding positions of the RPA to a computer, the computer receiving the transmitted stored recorded gas sensor readings and the corresponding positions of the RPA, and the computer performing the analysis of steps (ii) and (iii).

The method may be one wherein the gas sensor is a methane sensor.

The method may be one wherein the RPA includes a plurality of gas sensors, and the method includes recording gas sensor readings and the corresponding positions of the RPA for the plurality of gas sensors, the RPA storing the recorded gas sensor readings and the corresponding positions of the RPA for the plurality of gas sensors, and performing steps (ii) and (iii) for respective stored gas sensor readings.

According to a tenth aspect of the invention, there is provided a RPA including a drop tube, the drop tube in attachment with the RPA at a pivot position, wherein in an unreleased configuration the drop tube lies in a horizontal position and includes a payload within the drop tube, the RPA including a release mechanism, wherein the RPA is configured to release the release mechanism to release the drop tube into a released configuration, wherein in the released configuration the drop tube pivots about the pivot position, to cause the payload to be released from the drop tube. An advantage is the ability to deliver a payload from the RPA.

The RPA may be one wherein when the payload is released from the drop tube, the payload slides out of the drop tube.

The RPA may be one wherein the payload is released from, or slides out of, the drop tube under gravity.

The RPA may be one wherein the drop tube is in attachment with an underside of the RPA.

The RPA may be one wherein the underside of the RPA is the underside of the fuselage.

The RPA may be one wherein in the released configuration, the drop tube including the payload pivots about the pivot position under gravity.

The RPA may be one wherein the pivot position is near to a front of the RPA.

The RPA may be one wherein the drop tube has a length in the range of 1 m to 3 m.

The RPA may be one wherein the drop tube includes acrylic.

The RPA may be one wherein the payload includes a payload tube.

The RPA may be one wherein the payload includes a drogue chute.

The RPA may be one wherein the payload includes a parachute including a drogue chute.

The RPA may be one wherein the RPA includes a stored flight plan and a position determining apparatus, the RPA configured to release the release mechanism when the RPA position corresponds to a predetermined location in the flight plan at which the release mechanism is to be released. An advantage is unmanned release of the payload.

The RPA may be one wherein the RPA includes a transceiver, wherein the RPA is configured to release the release mechanism when the RPA receives a release command via the transceiver.

The RPA may be one wherein in flight, aerodynamic pressure causes the drop tube to swing back up so it returns to its position in the unreleased configuration.

The RPA may be one wherein the payload includes an Automatic Identification System (AIS) / DSC (Digital Selective Calling) beacon, including an Integrated DSC transmitter, which on contact with water or ground automatically activates.

The RPA may be one in which on contact of the payload with the water an inflatable marker is deployed, and/or a marker dye is released into the water.

The RPA may be one wherein the RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

According to an eleventh aspect of the invention, there is provided a method of carrying out an aerial survey in a region, the method including the steps of:

(i) an RPA flying from a taking off place to the region, the RPA including a camera system;

(ii) the RPA surveying the region, using the camera system, to capture images of significant portions of the region, and storing the captured images on the RPA, and

(iii) the RPA flying to a landing place; wherein the RPA includes a transceiver, the RPA receiving camera settings via the transceiver, and implementing the received camera settings on the camera system. An advantage is that the aerial survey can be performed in variable weather conditions.

The method may be one wherein the received camera settings include one or more of: Aperture size; Shutter speed; camera Azimuth angle; Adding filters to the camera lens(es).

The method may be one wherein the region is a region of a wind farm.

The method may be one wherein the region includes surrounding areas of the wind farm.

The method may be one wherein the wind farm is an offshore wind farm.

The method may be one wherein the wind farm is an onshore wind farm.

The method may be one including the RPA surveying the region performing one or more of: onshore pipeline monitoring (e.g. to detect leaks e.g. water leaks), inspecting weed distribution, crop monitoring, thermal surveying using thermal image cameras, mapping river habitats, mapping coastal habitats, mapping estuary habitats, identifying invasive non-native plants from the air, mapping algal blooms, mapping pollution, monitoring thermal plumes from the air.

The method may be one wherein the RPA uses a flight path including parallel sweeps with a fixed spacing and altitude that is selected in accordance with optical parameters of the camera system.

The method may be one wherein the RPA uses a flight path not including parallel sweeps with a fixed spacing and altitude.

The method may be one wherein the RPA sends a set of images based on the captured camera images (e.g. the set of images based on the captured camera images is sent at a rate of one per time interval e.g. one per minute), using the transceiver, back to a mission control centre, so the set of images based on the captured camera images can be reviewed at the mission control centre, e.g. to consider if the camera settings are appropriate. An advantage is that an improved aerial survey can be performed in variable weather conditions.

The method may be one wherein the set of images based on the captured camera images are at a lower resolution than the captured camera images. An advantage is quicker improvement to camera settings.

The method may be one wherein the captured images include images of birds and/or mammals. An advantage is improved characterization of the birds and/or mammals.

The method may be one wherein RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

The method may be one wherein during surveying the region, at least some of the time the RPA flies at an altitude of less than 600 m, or less than 400 m, or less than 200m.

The method may be one wherein the camera system is operated remotely.

The method may be one wherein the RPA flies using an auto pilot system included in the RPA.

The method may be one wherein the autopilot system is configured to fly a pre planned route.

The method may be one wherein the autopilot system receives the planned routes of other RPA(s) operating in the region, and avoids the flight paths of the planned routes of other RPA(s) operating in the region, to provide collision avoidance. An advantage is collision avoidance.

The method may be one wherein the autopilot system includes collision avoidance procedures. An advantage is collision avoidance.

The method may be one wherein the RPA takes off and lands from within 2 km of the coast. An advantage is reduced fuel usage. An advantage is reduced risk to people.

The method may be one wherein the camera system includes a daytime camera system.

The method may be one wherein the camera system includes a night time (e.g. infra red sensitive) camera system. An advantage is improved safety when operating in low light levels.

The method may be one wherein the transceiver provides a cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) link which is used to finely adjust any settings on the camera that needs low-latency feedback to do so effectively. An advantage is that an improved aerial survey can be performed in variable weather conditions.

The method may be one wherein the RPA is a RPA of any aspect of the second or third aspects of the invention.

According to a twelfth aspect of the invention, there is provided a method of carrying out an aerial survey in a region, the method including the steps of:

(i) a plurality of RPAs each including an autopilot and each receiving a respective flight plan, wherein the flight plans are configured so that the RPAs cannot collide during the aerial survey;

(ii) the plurality of RPAs flying from a taking off place to the region, the RPAs each including a respective camera system;

(iii) the RPAs surveying the region, using the respective camera systems, to capture images of significant portions of the region, and storing the captured images on the respective RPA, and

(iv) the RPAs flying to a landing place; wherein the RPAs each include a respective transceiver. An advantage is that the aerial survey can be completed during a brief favourable weather opportunity. The method may be one including the RPAs receiving camera settings via the transceiver, and implementing the received camera settings on the respective camera system.

The method may be one wherein a single pilot at a mission control centre is responsible for the plurality of RPAs flying simultaneously.

The method may be one wherein each RPA is an RPA of any aspect of the second or third aspects of the invention.

The method may be one wherein if one or more RPA aircraft have cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) coverage, this is used to relay the data from the other RPA aircraft back to the central control.

The method may be one wherein the cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) link is used to finely adjust any settings on the camera of the RPA aircraft having cellular coverage, or on another RPA aircraft, that needs low-latency feedback to do effectively. An advantage is that the aerial survey can be performed in variable weather conditions.

The method may be one wherein when the plurality of RPAs are being used in a surveying operation, each including and using a communications gateway unit of any aspect of the first aspect of the invention, or hardware with equivalent functionality, the plurality of RPAs communicate using their respective cellular transceivers, eg. respective 4G cellular transceivers.

The method may be one wherein when the plurality of RPAs are being used in a surveying operation, one RPA is designated as the master RPA; the master RPA receives data from the other RPAs, and then the master RPA transmits its data and the received data from the other RPAs via the satellite transceiver of the master RPA to mission control servers. The method may be one further including a method of any aspect of the eleventh aspect of the invention.

Aspects of the invention may be combined.

BRIEF DESCRIPTION OF THE FIGURES

Aspects of the invention will now be described, by way of example(s), with reference to the following Figures, in which:

Figure 1 shows an example system to achieve robust Command and Control.

Figure 2 shows an example of a Transition at a direct waypoint.

Figure 3 shows an example of a Transition at a circular waypoint.

Figure 4 shows an example of a Transition for waypoints that are close together. Figure 5 shows an example of a release mechanism and a drop tube, the drop tube including a payload tube and a drogue chute, in an unreleased configuration.

Figure 6 shows an example of part of a RPA and a drop tube, the drop tube including a payload tube and a drogue chute, in an unreleased configuration.

Figure 7 shows an example of a payload tube and an attached parachute, on the sea surface.

Figure 8 shows an example of systems of an unmanned aircraft-based apparatus. Figure 9 shows an example of what may comprise a Ground Control System.

Figure 10 shows an example in the horizontal plane in which the location of the source can be estimated in 3D by flying multiple circles of different radii, wherein one can project back towards the asset the line that intersects the ‘hot-spot’ of the source, at each radius.

Figure 11 shows an example in the vertical plane in which the location of the source can be estimated in 3D by flying multiple circle portions (e.g. semicircles) of different radii, wherein one can project back towards the asset the line that intersects the ‘hot- spot’ of the source, at each radius.

DETAILED DESCRIPTION

Example System for Efficient (e.g. Low cost) Beyond Visual Line of Sight Unmanned Air Services (UAS)

An objective is to achieve efficient (e.g. low cost) unmanned air services beyond visual line of sight.

In an example, a centralised C2 (command and control) architecture is provided. In an example of probabilistic management of risk, condition monitoring is used. In an example of probabilistic management of risk, live video feed is used. Example applications include: methane measurement; search and rescue; remote asset package drop; remote asset management; remote data collection and data relay; wind turbine inspection; Measuring Patterns for Emissions Sensing; Identifying the source of the emissions; performing aerial surveys; providing an offshore package drop.

Background

Being able to operate air services using drones beyond visual line of sight (BVLOS) requires the operator to prove that the system can run safely. The safety case typically relies heavily on having:

Situational Awareness Positional Awareness, and a good Command and Control system, so that the aircraft behaviour is predictable, and understood, at all times.

Here we outline a system and describe how:

1. The Positional Awareness and Command and Control is achieved using existing satellite (e.g. Iridium) and terrestrial (e.g. WiFi / cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) / low-power RF) networks together with an intelligent on board processing arrangement to provide Command and Control at improved efficiency (e.g. at a much-reduced cost), and that is generally applicable world-wide. The system must additionally manage the latency & low bit rate intrinsic to a cost effective and lightweight satellite.

2. The Situational Awareness is dealt with using our Overall System Risk framework and Mission Control user experience (UX).

Example Command and Control (C2) architecture

The Command and Control (C2) architecture is important (e.g. it is critical) for us to be able to scale the operation in terms of personnel. Effective BVLOS C2 typically require low-latency communications links, and existing systems tend to be proprietary and/or military based and thus are expensive and not generally applicable for commercial use due to use of restricted radio frequency (RF) licensed bands and/or RF power being above legislated levels. In a different version, we used a high- powered 433 MHz secure command link and a global positioning system (GPS) driven Autopilot when BVLOS, and an 868 MHz control link when having visual line of sight (VLOS).

Example System Architecture

There is provided a system to achieve robust Command and Control using a mixture of satellite communications (SatComms) and WiFi / cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) communications links, and an internet backbone to get the data back to our Local Ground Station and to our Mission Control Centre at a control centre. An example system to achieve robust Command and Control using a mixture of SatComms and WiFi / cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) communications links, and an internet backbone to get the data back to our local Local Ground Station and to our Mission Control Centre at a control centre, is shown in Figure 1.

In an example, a system is provided, the system including a Local Ground Station (LGS), a Mission Control centre in communication with the Local Ground Station, and a RPA in communication with the LGS, wherein the system is configured such that the RPA is configured to receive flight control commands from a pilot located at the Mission Control centre via the LGS. The system may include mission control servers and LGS software servers.

In an example, a Local Ground Station (LGS) is provided, the LGS including a LGS computer system executing LGS software. The LGS computer may communicate with a weather station, e.g. by WiFi. The LGS computer may communicate with test equipment. The LGS computer may communicate with LGS software servers. The LGS software servers may be in communication with LGS software operating on a respective computer system at a Mission Control Centre. The LGS may include a voice server, configured to receive voice commands, e.g. from a technician. The LGS voice server may be in communication with a voice server of a Mission Control centre. The LGS may include a Mission Control user interface, in communication with Mission Control Servers. The LGS computer may be in communication with an autopilot of a RPA. The LGS computer may be in communication with an intelligent communications gateway of a RPA (e.g. by WiFi).

In an example, an air traffic control system is provided. The air traffic control system may be operated by an air traffic controller. The air traffic control system may include a VHF transceiver, configured to communicate with an air band radio transceiver of a RPA. The air traffic control system VHF transceiver may be configured to communicate with the air band radio transceiver of the RPA via a VHF radio transceiver of one or more other air users e.g an aircraft piloted by a respective pilot.

In an example, mission control servers are provided. The mission control servers may be in communication with an intelligent communications gateway of a RPA using cellular communications (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G). The mission control servers may be in communication with an intelligent communications gateway of a RPA using satellite communications (e.g. via a satellite ground station, and via satellites using satcoms). The mission control servers may be in communication with a mission control user interface provided by a computer terminal at a Mission Control centre. The mission control servers may be in communication with a mission control user interface provided by a computer terminal at a customer office. The mission control servers may be in communication with a voice server of a Mission Control centre.

In an example, a Mission Control centre is provided. The Mission Control centre may be manned by an operations team including a watch manager, a systems engineer, a payload sensor engineer and a pilot, who may operate the mission control user interface, the voice server or the LGS software. The Mission Control centre may include a customer liaison officer. The customer liaison officer may communicate by phone with a customer representative of a customer office. The customer liaison officer may communicate by phone with an offshore installation manager of a remote asset (e.g. oil rig or gas rig).

In an example, a Remotely Piloted Aircraft (RPA) is provided. The RPA may include an intelligent communications gateway. The intelligent communications gateway may be configured to communicate by cellular communications (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) with mission control servers. The intelligent communications gateway may be configured to communicate by satellite communications (e.g. via satellites and a satellite ground station) with mission control servers. The RPA may include a Tracker which is configured to communicate by satellite communications (e.g. via satellites and a satellite ground station) with mission control servers. The intelligent communications gateway may be configured to communicate by WiFi or by cellular communications (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) with servers of a remote asset (e.g. oil rig or gas rig). The RPA may include a sensor, the sensor arranged to communicate with the intelligent communications gateway. The RPA may include an autopilot, the autopilot arranged to communicate with the intelligent communications gateway, and/or the autopilot arranged to communicate with a transceiver for automatic dependent surveillance-broadcast (ADS-B) included in the RPA, and/or the autopilot arranged to communicate with LGS software in the LGS. The RPA may include a VoIP to VHF switch and an air band radio, wherein the intelligent communications gateway is configured to communicate via the VoIP to VHF switch, via the air band radio with a VHF radio transceiver of other air users (e.g. piloted aircraft), or with a VHF radio transceiver of air traffic control, or with a VHF radio transceiver of a remote asset. The VHF radio transceiver of the remote asset may be operated by a radio operator.

A communications link may be a wired communication link. A communications link may be a wireless communications link. The mission control servers may be configured to control a plurality of RPAs simultaneously, e.g. two RPAs simultaneously, or three RPAs simultaneously.

An RPA may include an airband radio transceiver. A LGS may include an airband radio transceiver. An RPA may have a length in the range of 1 m to 5 m, or 1 m to 3 m.

An unmanned aircraft-based apparatus may include an air band radio, which may include one or more of: radio control interface; RoIP (radio over internet protocol) codec. An unmanned aircraft-based apparatus may use Voice over Internet Protocol (VOIP) / Radio over Internet Protocol (ROIP) to ATC to talk to other aircraft. An unmanned aircraft-based apparatus may include a methane sensor. An unmanned aircraft-based apparatus may include local storage which may include one or more of: a Methane sensor can be reset by pilot; sample data is communicated back by the low earth orbit (LEO) (e.g. Certus, Iridium L band)/ cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) unit; Complete data stored locally. An unmanned aircraft-based apparatus may include a low earth orbit (LEO) (e.g. Certus, Iridium L band) satellite and cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) communications unit, which may include one or more of: Switches between LEO and cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G), or between a plurality of cellular links (e.g. to get better coverage), based on availability; Minimal downtime (possibly duplicate low earth orbit (LEO) (e.g. Certus, Iridium L band)). An unmanned aircraft-based apparatus may include a watchdog (may be in an autopilot), which may include one or more of: Implements predetermined failsafes; may be part of an (e.g. Pixhawk) autopilot, or may sit outside autopilot. An unmanned aircraft-based apparatus may include a receiver for WiFi (2.4GHz) and/or 433 MHz frequencies, which may include one or more of: Receiver and antennas; Suitable for range of about 3 miles. An unmanned aircraft-based apparatus may include a (e.g. Pixhawk) autopilot, which may include one or more of: Customised firmware to desired behaviour and minimise bit rate; mounted directly onto power distribution printed circuit board (PCB) within enclosure. An unmanned aircraft-based apparatus may include a tracker, e.g. an independent satcoms tracker. An unmanned aircraft-based apparatus may include power, servos, pitot, GPS receiver or other satellite-based position receiver, etc, which may include one or more of: Power management done on PCB; Minimal and rugged connectors; Redundancy in sensors. An unmanned aircraft-based apparatus may include Mode S transponder and ADS-B out, which may include one or more of: an ADSB-Out unit (e.g. PING 200X unit); Antenna and GPS (certified) or other satellite-based position receiver, linked to unit; Squawk can be changed remotely by the pilot. An unmanned aircraft-based apparatus may include ADS-B in, which may include one or more of: an ADSB-In unit (e.g. PING RX unit); Feeds data into the autopilot (e.g. Pixhawk).

An example of systems of an unmanned aircraft-based apparatus is shown in Figure 8.

A Ground Control System may include adapted flight control software, which may include one or more of: Shows position on other aircraft from ADS-B in on aircraft; Shows flight plan; Customised user interface (UI) to improve accuracy and assist following procedures. A Ground Control System may include a 2.4 GHz or 433 MHz transmitter, which may include one or more of: Handheld unit; Requires no regulatory (e.g. OFCOM) licence; Gives about 3 mile range. A Ground Control System may include an internet link to low earth orbit (LEO) (e.g. Certus, Iridium L band) satellite and cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) communications unit, which may include one or more of: Secure and reliable connection; Low latency. A Ground Control System may include Radio over Internet Protocol (ROIP) / Voice over Internet Protocol (VOIP) link to fixed VHF antennas near an ATC, which may include one or more of: Pilot can speak and voice is transmitted from antenna; Pilot can hear what is received by VHF antenna; Pilot can change frequency of antenna. A Ground Control System may include automatic landing, which may include: Aircraft must be able to land in fog conditions. A Ground Control System may include ROIP/VOIP link to fixed VHF antenna on aircraft, which may include one or more of: Pilot can speak and voice is transmitted from aircraft; Pilot can hear what is received by VHF at aircraft; Pilot can change frequency. A Ground Control System may include a fixed VHF antenna, which may include one or more of: Fixed VHF transceiver near air traffic control (ATC) (and possibly offshore); Pilot can transmit, receive and change frequency.

An example of what may comprise a Ground Control System is shown in Figure 9. Further Details

Any methods, systems or apparatus described may include the following listed features. Any features can be combined with any one or more other features.

1. Use of lower fidelity digital video/images for making tactical decisions on where to ditch the aircraft if we have to e.g. to check to see if we are heading for a ship or a school etc. This is distinguished from existing streamed First Person View video solutions in that it is used as part of our decision support procedures to handle discrete events such as ditching or bird-strike safety.

2. The decision as to using the airband radio (VHF transceiver) on the aircraft (with RoIP over the satellite link) or as a unit near ATC (using RoIP over the internet) is situational: if we are only flying in one airspace sector, we use the fixed land-based airband radio to save weight and satellite bandwidth, and use ATC infrastructure to talk to other planes, but if we are flying across many airspace sectors, this is not efficient for ATC and we would be asked to use the airband radio on the aircraft.

3. Although the aim is to run the operation centrally, there is nothing stopping a BVLOS pilot from controlling the aircraft wherever they are, as long as they have a good connection to the internet.

4. Our RPA can automatically set the Mode S emergency squawk code in the case of loss of communications so that other air users and ATC can see that there is an issue and avoid the area / divert planes accordingly.

5. If there are more than one RPA flying in the same vicinity, the data relay can be used to send data between aircraft to help if there is a problem with for example the satellite C2 link on one aircraft, enabling us to return safely without triggering "communications lost" emergency squawk code that results in airspace being locked down until incident is over. 6. Our RPA has a simple Detect and Avoid strategy that only adjusts the RPA altitude to maintain altitude separation as long as it is above a safe height above the deck. If aircraft approach, one from above and one from below, the RPA adjusts its altitude to be in the middle.

7. Our satcoms antenna is fitted with a simple roll gimbal (e.g. with tuned damping) to ensure that the antenna is level and thus has good connection even when the aircraft is banking as it circles the asset or takes avoiding action.

8. Our RPA can turn on and off its sensor package automatically to save energy if needed.

9. Our RPA has a real-time fuel estimation algorithm that alerts the pilot if we need to turn back in order to return with a set amount of fuel reserve (See e.g. ‘Fast calculation of remaining mission path and fuel use’ described below).

10. Details on our proposed package-drop mechanism (See e.g. ‘Offshore package drop mechanism ’ described below).

Communications gateway Unit examples and RPA examples

There is provided a communications gateway unit for a Remotely Piloted Aircraft (RPA). The communications gateway unit may be installable into, and removable from, the RPA. The unit may be cuboid shaped, for example of approximate dimensions 25 cm by 15 cm by 10 cm. The unit may have a volume in the range 2000 cm³ to 8000 cm³. The unit includes at least a satellite communications transceiver, a first cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver and a second cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver. The satellite communications transceiver, the first cellular transceiver and the second cellular transceiver may be used for bi-directional data communications. In use, the communications gateway unit may be installed inside a wing of the RPA. In normal use, the communications gateway unit may provide a satellite communications link from the RPA to a mission control server, and at least one cellular communications link from the RPA to the mission control server, using the first cellular transceiver or using the second cellular transceiver. In normal use, this provides at least two communications links from the RPA to the mission control server. It has been found that use of these at least two communications links from the RPA to the mission control server, including a satellite communications link and a cellular communications link, makes operation of the RPA very safe.

In an example, the communications gateway unit is at least suitable for transmitting tracking data from a RPA to a LGS or to a mission control server, via network infrastructure.

An advantage of having available two or more communications links is that the communications gateway unit can choose/determine the appropriate communication link to send data to the mission control.

An advantage is that the RPA can be operated without using an antenna system of an ATC. The communications gateway unit may optionally include a WiFi transceiver. An advantage is that the WiFi transceiver can be used to transfer data while the RPA is at an airfield, or while the RPA is flying closely around a target site (e.g. oil rig, gas rig). The communications gateway unit may optionally include a GPS sensor.

The communications gateway unit may use a multi-objective cost function to determine an appropriate link to send data over. An advantage is lower cost operation of the system.

The communications gateway unit may be one wherein the cost function is or includes Route(t) = arg min{ J SatComms, J First cellular, J Second cellular }, subject to the latency < critical time, where J_{xx} = cost per data throughput. A cost term may also be included in the cost function in relation to energy consumed, which changes with distance for each link, or a cost term may also be included in the cost function in relation to power consumed. A cost term may also be included in relation to the Round-Trip Time (RTT) of each link. An advantage is lower cost operation of the system, while maintaining safety, because the latency < critical time.

The communications gateway unit may store telemetry data. The communications gateway unit may store position data, e.g. as determined using a GPS antenna and a processor, e.g. included in the communications gateway unit. The communications gateway unit may include a serial port. Telemetry data stored on the communications gateway unit (e.g. position, GPS data, altitude, acceleration, pressure, gas sensor (e.g. methane)) may be received by an external computer connected to the serial port, e.g. when the RPA has returned to its base. The communications gateway unit may include a USB port. Telemetry data stored on the communications gateway unit (e.g. position, GPS data, altitude, acceleration, pressure, gas sensor (e.g. methane)) may be received by an external computer connected to the USB port, e.g. when the RPA has returned to its base.

The communications gateway unit may be operated by an external computer in communication with the communications gateway unit, such as being in communication with the communications gateway unit using the satellite transceiver, or using the first cellular transceiver or using the second cellular transceiver. The communications gateway unit may be operated by an external computer in internet communication with the communications gateway unit, such as being in communication with the communications gateway unit using the satellite transceiver, or using the first cellular transceiver or using the second cellular transceiver.

The communications gateway unit may be such that the first cellular transceiver (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) and the second cellular transceiver (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) are configured to use different cellular networks.

The first cellular transceiver may be a 4G cellular transceiver. The second cellular transceiver may be a 4G cellular transceiver. We have found that a 4G cellular transceiver provides the advantage of long range transmission and reception. A 4G cellular transceiver may provide a range of approximately 25 miles.

There is provided an RPA including the communications gateway unit. The communications gateway unit may be housed by the RPA. The RPA including the communications gateway unit may be able to fly during the daytime, or during the nighttime. The RPA including the communications gateway unit may provide RoIP or VoIP communications, using the satellite transceiver, or using the first cellular transceiver or using the second cellular transceiver.

In an example, the first cellular (e.g. a non-roaming) transceiver is configured to communicate with a network that is an inshore network, i.e. a network that provides coverage over a water area but near to a coast, and/or over a coastal area that is near to a water area, and the second cellular (e.g. a roaming) transceiver is configured to communicate with a cellular network e.g. one that is not an inshore network. An advantage is that the communications gateway unit can use (e.g. to transmit and receive data) the communications network which is most suitable for communications at a given place during its journey. For example, when flying above the sea near to the coast, the communications gateway unit may use (e.g. to transmit and receive data) the first cellular (e.g. the non-roaming) transceiver that is configured to communicate with a network that is an inshore network. For example, when flying above the land near to the coast, the communications gateway unit may use (e.g. to transmit and receive data) the second cellular (e.g. the roaming) transceiver that is configured to communicate with a network that is not an inshore network. For example, when flying far out at the sea not near to the coast, the communications gateway unit may use (e.g. to transmit and receive data) the satellite transceiver that is configured to communicate with a satellite communications network, for example because no cellular communications network is available.

A cellular transceiver may be configured as a roaming cellular transceiver by use of a roaming SIM card within the cellular transceiver. A cellular transceiver may be configured as a non-roaming cellular transceiver by use of a non-roaming SIM card within the cellular transceiver.

A transceiver for automatic dependent surveillance-broadcast (ADS-B) may be included in the RPA. The transceiver for automatic dependent surveillance-broadcast (ADS-B) may be used for collision avoidance.

In an example, for a RPA including the communications gateway unit, the primary command and control of the RPA is via the satellite transceiver. Alternatively primary command and control of the RPA may be provided via the first cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver or via the second cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver. In an example, primary command and control of the RPA may be switched from being via the satellite transceiver, to being via the first cellular transceiver or via the second cellular transceiver. In an example, primary command and control of the RPA may be switched from being via the first cellular transceiver or via the second cellular transceiver, to being via the satellite transceiver. In an example, the switching occurs seamlessly.

In an example, a RPA may include a UHF transceiver. The UHF transceiver may be used to communicate telemetry data. An advantage is faster communication of telemetry data, and faster reception of any response to transmitted telemetry data.

In an example, a RPA may include a Light Detection and Ranging (LIDAR) measurement system arranged to measure the distance above the ground or water of the RPA when in flight. In an example, the distance above ground or water measured using the LIDAR measurement system may be compared with a GPS position, possibly supplemented by barometric pressure, to confirm that the distance above ground or water measured using the LIDAR measurement system is accurate. An advantage is reduced risk of collision with the ground or water.

The RPA may be configured to determine a difference between the LIDAR measurements of the distance above the ground or water of the RPA when in flight and the distance above the ground or water of the RPA when in flight estimated using GPS and/or barometric pressure. The RPA may then be configured to automatically recalibrate the distance above the ground or water of the RPA when in flight estimated using GPS and/or barometric pressure using the determined difference. Alternatively, the RPA may then be configured to automatically recalibrate the distance above the ground or water of the RPA when in flight measured using LIDAR using the determined difference.

The RPA may include a video camera. The video camera may be configured to record video at a higher rate during take off and/or landing, and to record video at a lower rate at other times e.g. when flying over water. Example Fast calculation of remaining mission path and fuel use Overview

We have developed algorithms (e.g. an algorithm) that take the current aircraft position and the waypoints remaining in the mission and calculates the approximate path that the aircraft will take. This is a purely geometric calculation and has the advantage of being very fast to calculate (as opposed to simulating the aircraft controls and flight dynamics).

This is useful as it allows us to:

1. Visually display the remaining journey on a map

2. Estimate the remaining distance in the flight

An important feature of an example algorithm is that the approximate path is calculated as a series of segments which are straight lines and circular arcs. We know the velocity of the aircraft in still air and it is then straightforward to calculate the flight time of every segment for a given wind speed and direction. If we also assume a fuel burn rate, we can:

1. Estimate the remaining time in the flight

2. Estimate the remaining fuel that will be used in the flight

This is useful as it allows us to calculate the likely range of fuel that we will have on landing based on a range of wind scenarios. If any of the range of fuel that we will have on landing falls below a predefined threshold, the mission may be automatically aborted, or curtailed, to avoid running out of fuel during the mission.

Although in an example, an algorithm may be executed off-board, it may be executed as part of an on-aircraft fuel prediction calculation.

An Example Algorithm

Waypoints may come in two varieties - direct and circular. Direct waypoints are those we fly directly to, circular waypoints are those that we fly around in a circle at a prescribed radius. When the aircraft has to turn a corner to fly towards the next waypoint it does this by flying through a circular arc of constant radius such that the ends of the arc are tangential to the straight lines between the waypoints before and after the turn.

An example algorithm to calculate the remaining flight path is: Get initial position of the aircraft, I For each waypoint:

• Get the position of next two waypoints, W2 and W3

• Calculate the straight segment S from I to W2 and the arc segment A which smoothly transitions from the I-W2 to W2-W3 lines.

• If the start of A is in an infeasible position, calculate the shortest double arc segment BC from I to the W2-W3 line

• Set I to be equal to the end of segment A (if feasible) or B-C (otherwise)

• Store all calculated segments

The following plots show examples of the paths that are generated by this example algorithm. Figure 2 shows an example of a Transition at a direct waypoint. Figure 3 shows an example of a Transition at a circular waypoint. Figure 4 shows an example of a Transition for waypoints that are close together.

Once the positions of each segment are known it is trivial to calculate the total length of the remaining path. The relationship between the ground speed Vg_round, air speed v_air and wind speed v_Wmd may be given by:

Where Q is the angle between the wind and the direction over the ground.

This equation gives us the ground speed for a specific wind speed and direction, which gives us time taken to fly a straight segment and we can integrate this with respect to theta to find the time taken to fly an arc segment. The total remaining flight time is simply the sum of all of the segment flight times, in an example.

In an example, the expected fuel use is simply the fuel burn rate multiplied by the total remaining flight time.

Applications for Efficient (e.g. Low Cost) Beyond Visual Line of Sight Unmanned Air Services Here we describe applications of efficient (e.g. low cost) unmanned air services beyond visual line of sight.

Approach and Measuring Patterns for Emissions Sensing

We have run a number of BVLOS flights to remote oil and gas assets to measure methane concentration and therefore calculate the overall emission of the asset. This is an important application. Methane is a greenhouse gas, hence measurement of its emission is important in understanding the world’s changing climate. Measurement of methane may indicate a gas leak on an offshore installation, which could have adverse safety implications, e.g. risk of an explosion.

The flight path

The methane sensor is a point sensor that measures the local concentration of methane. The ideal is to capture an instantaneous set of readings at every point on a complete dome surrounding the asset. This encloses the asset in a complete perimeter that enables us to calculate all of the methane in and out of the enclosed space. Because the methane has a different buoyancy than the surrounding air, it is possible for cold releases to drop close to the sea surface and potentially escape below an incomplete dome or for hot methane to rise vertically from the asset and go out through a gap in the top of the dome. By combining these methane measurements with windspeed and direction (e.g. measured by the unmanned aircraft or on the asset) and comparing concentrations across the dome, the flow rate of gas from the asset can be calculated.

In reality there are a number of limitations that make the ideal data set above difficult to achieve:

1. It is not possible to take readings at every point at once using a sensor on a single aircraft.

2. Each oil and gas asset has a (e.g. 500m) exclusion zone around it. Permission is required to enter this zone and activity here may interrupt other critical operations.

3. Overflying the asset increases the risk of hitting the asset in the event of loss of power on the aircraft or an error in altitude.

4. Flying close to the sea risks collision with waves or vessels due to altitude errors by both GPS (or other satellite-based position receiver) and barometric, or large waves.

Therefore we have identified two more practical compromises:

A. We investigate over a tall cylinder that has a radius of just greater than 500m and extends to close to sea level and then well above the height of the tallest features on the oil and gas asset. The lower level is set by error bars in altitude sensors, wave height and vessels.

B. We investigate over a cone shape that is greater than 500m at its base and then tapers to less than 500m above the height of the asset to still avoid direct overflight but reducing the height of the exit chimney with similar lower restriction.

In each case the aircraft flies a series of circles at increasing or decreasing altitudes with short ascents or descents, respectively, to a new altitude. Alternatively, a more efficient but complex flight path is a continuous helix.

This approach makes sense when the asset is a single object that is fixed to the seabed and can be approximated to be a point. In practice many fixed offshore structures are an amalgamation of several structures and so are more complicated.

In that event, if the flight path remained circular and the flight had to maintain a minimum of 500m from the set of targets, the cylinder would become very large. This would reduce accuracy (due to range) and increase flight duration. Therefore a more attractive route might be an oblong shape (i.e. a shape that is longer than it is wide) or a stadium shape. The cone shape could similarly be adapted to a set of targets.

In many cases the offshore structure is floating. Structures like Spars and SemiSubs move on their moorings. This is typically 1% of water depth in normal conditions but can be as great as 10% of water depth in extreme events. As it is desirable for the unmanned system to maintain a known separation from the asset, then the distance from the nominal centre point of the asset must be increased to accommodate mooring movement. This can be refined with a knowledge of wind direction, tide and live feed from asset.

In some cases moored structures are ship shaped and move around moored turrets. Their position is impacted by wind, waves and tides. The hull may extend out several hundred meters behind the centre of rotation which itself will be moving as it is moored. This can describe a very large perimeter for the aircraft to investigate. A knowledge of weather and vessel heading can be used to optimize the investigation.

Many offshore structures are small unmanned assets with little methane emission in normal operation because they have very little process plant. It may be inefficient to complete a detailed survey of each of these smaller assets like above and so a triage approach can be adopted. The aircraft can fly a series of simple passes of multiple smaller assets to detect an emission signature and then only conduct a detailed survey of those with a significant emission. For example, the aircraft may pass downwind of a number of smaller assets. It may complete a series of passes at different altitudes to compensate for buoyancy effects of methane but still it can cover far more assets in one flight in this way. If the flight path is selected to weave between assets it is possible to compensate for the effect of upstream assets. Ultimately this coarser technique can be stitched together to create a virtual emission map of a very large area.

This approach can be extended to moving emitters like commercial shipping where the aircraft flies a regular fixed route across a busy shipping channel and simply allows vessels to pass by. Again, if a particular vessel has a large signature the aircraft can fly a moving cylinder around it to obtain an accurate emission picture. This creates a virtual cylinder.

Example of identifying the source of the emissions:

In the case where the emissions are coming from distinct sources, the location of these sources can be estimated in 3D by flying multiple circles of different radii, wherein one can project back towards the asset the line that intersects the ‘hot-spot’ of each plume, at each radius. In the case where the emissions are coming from a distinct source, the location of the source can be estimated in 3D by flying multiple circles of different radii, wherein one can project back towards the asset the line that intersects the ‘hot-spot’ of the source, at each radius. An example in which the location of the source can be estimated in 3D by flying multiple circles of different radii, wherein one can project back towards the asset the line that intersects the ‘hot-spot’ of the source, at each radius, is shown in the horizontal plane example of Figure 10. The approach for the location in the vertical plane is similar. For example, the location of these sources can be estimated in 3D by flying multiple circle portions (e.g. semicircles) of different radii, wherein one can project back towards the asset the line that intersects the ‘hot-spot’ of each plume, at each radius. In the case where the emissions are coming a distinct source, the location of the source can be estimated in 3D by flying multiple circle portions (e.g. semicircles) of different radii, wherein one can project back towards the asset the line that intersects the ‘hot-spot’ of the source, at each radius. An example in which the location of the source can be estimated in 3D by flying multiple circle portions (e.g. semicircles) of different radii, wherein one can project back towards the asset the line that intersects the ‘hot-spot’ of the source, at each radius, is shown in the vertical plane example of Figure 11.

Notes:

• The tracks need not be circular

• The method is not limited to a single source but when there are multiple sources, there may be multiple solutions which need to be resolved using additional information.

Obtaining the solution for the location of the emissions source could range from performing a simple geometrical calculation to performing a full-blown 3D Computational Fluid Dynamics (CFD) diffusion computation, for example including using estimates of the wind field and asset shape.

In an example, the operation to an individual asset starts with planning and simulating the route for the mission.

In an example, the methane level data is measured every few seconds.

We can use the difference in gases to help identify and pin-point what type of leak. For example excess methane with no C02 implies cold vent. C02 with methane implies incomplete combustion: say flare or turbine.

With a small modification of the sensor, a similar approach can be extended to measuring other gases, such as fluorinated gases (F-gases) (e.g. hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6) or nitrogen trifluoride (NF3)), or NOx or SOx, for monitoring of remote assets, using respective sensor(s). Example Approach for Aerial Surveys

Aerial surveys such as those carried out for Birds and/or Mammals when consenting and operating offshore wind farms or onshore wind farms require very detailed images or video to be captured of significant portions of the wind farm and surrounding areas at regular intervals so that the inspectors (e.g. ornithologists) can:

• Identify which species exist in the area - in the air and in the sea itself

• Identify any change in behaviour of these species due to the wind farms

• Identify migratory paths so that the wind turbines are not placed in those paths

• confirm that there has been no significant disruption to bird and/or mammal life caused by the wind farm.

Such surveys may need to be carried out once, twice, or more times, per year.

To date these surveys have been carried out by small twin-engine fixed wing aircraft with a pilot and a dedicated camera operator. The flight paths tend to be parallel sweeps with a fixed spacing and altitude that is carefully calculated depending on the optics of the camera system. It is a skilled endeavour and there are several factors that may need to be managed, which may also need to be managed in our applications:

• The direction and elevation of the sun

• The direction of the waves

• Wind induced ‘white horses’ or surface spray

• Cloud cover

• Cloud movements

• Aircraft capability (range, turn radius)

• Aircraft noise and shadow and their impact on behaviours of the birds & mammals themselves

• Vibration levels

• Turbulence

• Other air users

• Runway surface conditions (e.g.: dry, wet, or icy)

We propose the use of RPAs (e.g. fixed-wing unmanned aircraft) to improve the safety, environmental impact and cost of the operation by removing the need for people in the aircraft and being able to scale the number of aircraft e.g. using the Low-cost BVLOS centralisation of control.

The smaller size of the unmanned aircraft could also reduce the impact on the behaviours of the birds & mammals and thus obtain more objective measurements.

In an example, the main aspects of this aspect of our invention are:

Remote camera control

The remote camera operator needs to ensure the pictures or video are of high enough quality that the inspectors (e.g. ornithologists) can accurately identify the species of animal in the picture. There are a number of settings that the remote operator can optimise during the flight to do so, for example:

• Aperture size

• Shutter speed

• Azimuth angle

• Adding filters to the lenses (anti-glare)

• Asking pilot to modify flight path

To do this remotely, we would use our multiple link communications system (e.g. using the communications gateway unit described above) to send images at an appropriate resolution back to the remote operator for them to assess and make adjustments over the same links back to the camera system in real-time. The remote operator can also make requests to the RPA pilot to modify the altitude, speed or flight path using an intercom system (e.g. VoIP).

Multiple vehicles

The unmanned RPA aircraft have advanced autopilot functions that allow the pilot to program complex routes and have an on-board collision avoidance strategy so that multiple RPA aircraft can be operated in the same area simultaneously and safely.

We propose using multiple unmanned RPA aircraft to perform the surveys because they:

• can cover the area faster than a single manned aircraft therefore taking a more accurate ‘snapshot’ of the wildlife at a fixed point in time. A set of search patterns may be automatically determined such that the set of search patterns covers a specific area without the risk of collision of the multiple unmanned RPA aircrafts

• can get closer to a wind farm or to a specific area of interest to be surveyed, compared to a manned aircraft • can make best use of smaller weather windows

• can take off close to the coast (e.g. using a farmer’s field) to reduce transit times and fuel usage

• can be coordinated centrally by a single pilot making the operation safer than having the RPA aircraft being flown independently of each other.

Data relaying

If one or more RPA aircraft have cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) coverage, we can use it to tether the data from the other RPA aircraft using line-of- sight data relays to make use of this high-speed link back to the central control to send higher quality images than can be done with only the satellite corns.

The cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) link can also be used to finely adjust any settings on the camera that need low-latency feedback to do effectively. Mission profile

The unmanned RPA aircraft can safely operate at lower altitude than a manned aircraft. This reduces the impact of low level cloud and allows a smaller, more cost effective, camera system to gather similar quality data to that in a manned aircraft system. This also enables the unmanned RPA aircraft to operate below the flight level of other air users, reducing the impact of these operations.

The unmanned RPA aircraft can manoeuvre more tightly than a manned aircraft and thus can complete the turns with tighter radius and thus spacing which reduces the time and fuel used on these ‘edge effects’. An RPA is safer than a manned aircraft because in an RPA no pilot or crew’s life is put at risk.

An RPA may use a communications gateway unit as described above. An RPA may include and use hardware whose functionality is equivalent to a communications gateway unit as described above.

An RPA may conduct a survey by flying a flight path that is stored before the RPA takes off. In an example, a pilot at a mission control centre may be responsible for one, two or three RPAs flying simultaneously, or for a plurality of RPAs flying simultaneously. A plurality of RPAs (e.g two or three) may conduct a survey by each RPA flying a respective flight path (e.g. stored as a function of time) that is stored before the respective RPA takes off, to ensure that no two RPAs can collide. This has the advantage of ensuring safety, while using RPA and/or LGS and/or Mission Control resources efficiently.

During surveying, an RPA may send back some video images to the mission control servers, e.g. via satellite. These images can be checked at the LGS and/or mission control centre. In response to an inspected image being identified as sub-optimal, revised camera settings can be transmitted to an RPA and implemented in the video camera of the RPA.

When two, three or more RPAs are being used in a surveying operation, each including and using a communications gateway unit (or hardware with equivalent functionality) as described above, the two, three or more RPAs may communicate using their respective cellular transceivers, eg. respective 4G cellular transceivers. When the two, three or more RPAs are being used in a surveying operation, one RPA may be designated as the master RPA; the master RPA may receive data from the other RPAs, and then the master RPA may transmit its data and the received data from the other RPAs via the satellite transceiver of the master RPA to mission control servers.

An advantage of an RPA being used in a surveying operation is that the RPA can fly lower than a manned aircraft, without endangering the life of a pilot or crew. By flying lower, the RPA may be able to record higher resolution images of ground level or water level features than a manned aircraft, when a given camera system is used. A camera system may include a daytime camera system. A camera system may include a night time (e.g. infra red sensitive) camera system, for example for use if an RPA is flown at night.

The one or multiple unmanned RPA aircrafts may therefore also perform a survey at night or under foggy conditions, each aircraft using a respective night time (e.g. infra red sensitive) camera system. The one or multiple unmanned RPA aircrafts may perform a survey under icy conditions.

Apart from surveying of birds and/or mammals using RPAs, other surveying applications using RPAs include one or more of: onshore pipeline monitoring (e.g. to detect leaks e.g. water leaks), inspecting weed distribution, crop monitoring, thermal surveying using thermal image cameras, mapping river habitats, mapping coastal habitats, mapping estuary habitats, identifying invasive non-native plants from the air, mapping algal blooms, mapping pollution, monitoring thermal plumes from the air. An RPA may have a length in the range of 1 m to 5m, or 1 m to 3 m. A plurality of RPAs may have respective lengths in the range of 1 m to 5 m, or 1 m to 3 m.

Offshore package drop mechanism example

There is provided a (e.g. 150mm length) (e.g acrylic) Drop Tube, a (e.g. orange) Payload Tube and an attached drogue chute. The plan is to fix the drop tube under the fuselage of the aircraft and drop the payload tube towards the water (e.g. sea) when the aircraft is close to a customer's asset. An example of a drop tube, including a payload tube and a drogue chute, in an unreleased configuration, is shown in Figure 5. A drogue chute is a small parachute used to pull out a larger parachute or other object from an aircraft in flight.

The drop tube is fixed at the front of the aircraft and pivots downwards when the release instruction is given; the release mechanism (on the top of the tube) is fixed to the bottom of the aircraft and holds the release tube in place during flight. When released, the release tube will pivot downwards and the payload will slide downwards and out of the tube. When the payload has cleared the drop tube, aerodynamic pressure will or may cause the tube to swing back up into position thereby reducing drag. We may need to install fins on the drop tube so it returns to its original position. An example of a drop tube, including a payload tube and a drogue chute, in an unreleased configuration, is shown in Figure 6.

When clear of the aircraft the drogue chute will automatically deploy, and the parachute will substantially reduce the payload's impact with the water. In an example, on entering the water an Automatic Identification System (AIS) / DSC (Digital Selective Calling) beacon, including an Integrated DSC transmitter, will automatically activate and an Inflatable marker will deploy, in addition a (e.g fluorescent) (e.g. green) marker dye may be released into the water. The parachute may also serve as sea anchor until the payload is recovered from the water. An example of a payload tube and an attached parachute, on the sea surface, is shown in Figure 7.

Note As used herein, “GPS” denotes a satellite positioning system, e.g. the USA’s Global Positioning System, or Beidou (China), or Galileo (EU), or GLONASS (Russia), or NavIC (India), or QZSS (Japan). It is to be understood that the above-referenced arrangements are only illustrative of the application for the principles of the present invention. Numerous modifications and alternative arrangements can be devised without departing from the spirit and scope of the present invention. While the present invention has been shown in the drawings and fully described above with particularity and detail in connection with what is presently deemed to be the most practical and preferred example(s) of the invention, it will be apparent to those of ordinary skill in the art that numerous modifications can be made without departing from the principles and concepts of the invention as set forth herein.

Claims

1. A communications gateway unit, the communications gateway unit including at least a satellite communications transceiver, a first cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver and a second cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver.

2. The communications gateway unit of Claim 1, wherein the satellite communications transceiver, the first cellular transceiver and the second cellular transceiver are configured for use for bi-directional data communications.

3. The communications gateway unit of any previous Claim, wherein the communications gateway unit is arranged such that the first cellular transceiver (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) and the second cellular transceiver (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) are configured to use different cellular networks.

4. The communications gateway unit of any previous Claim, wherein the first cellular transceiver is a 4G cellular transceiver.

5. The communications gateway unit of any of Claims 1 to 3, wherein the first cellular transceiver is a LoRa gateway transceiver.

6. The communications gateway unit of any previous Claim, wherein the second cellular transceiver is a 4G cellular transceiver.

7. The communications gateway unit of any previous Claim, wherein the first cellular (e.g. a non-roaming) transceiver is configured to communicate with a network that is an inshore network.

8. The communications gateway unit of any previous Claim, wherein the second cellular (e.g. a roaming) transceiver is configured to communicate with a cellular network that is not an inshore network.

9. The communications gateway unit of any previous Claim, wherein the first cellular transceiver is a non-roaming transceiver, and the second cellular transceiver is a roaming transceiver.

10. The communications gateway unit of any previous Claim, wherein the satellite transceiver includes an antenna and a roll gimbal (e.g. with tuned damping) to ensure that the antenna is level and thus has good connection when banking.

11. The communications gateway unit of any previous Claim, wherein the communications gateway unit is configured to provide a satellite communications link to a server, and at least one cellular communications link to the server, using the first cellular transceiver or using the second cellular transceiver.

12. The communications gateway unit of any of Claims 1 to 10, wherein the communications gateway unit is configured to provide a satellite communications link to a server, and at least two cellular communications links to the server, using the first cellular transceiver and using the second cellular transceiver.

13. The communications gateway unit of Claims 11 or 12, wherein the server is a mission control server.

14. The communications gateway unit of any previous Claim, the communications gateway unit receiving positional data from an autopilot, wherein the autopilot is configured to determine a position of the communications gateway unit using a GPS antenna, and to store the determined position of the communications gateway unit in a storage medium of the communications gateway unit.

15. The communications gateway unit of any previous Claim, wherein the communications gateway unit is configured to transmit a determined position of the communications gateway unit to a server.

16. The communications gateway unit of any previous Claim, wherein each transceiver is operable to provide a communication link, wherein the communications gateway unit is configured to choose and/or to determine an appropriate communication link to use to send data.

17. The communications gateway unit of Claim 16, wherein the communications gateway unit is configured to use a multi-objective cost function to determine an appropriate link to send data over.

18. The communications gateway unit of Claim 17, wherein the cost function is or includes Route(t) = arg min{ J SatComms, J First cellular, J Second cellular }, subject to the latency < critical time, where J_{xx} = cost per data throughput.

19. The communications gateway unit of any previous Claim, wherein each transceiver is operable to provide a communication link, wherein the communications gateway unit is configured to store telemetry data.

20. The communications gateway unit of Claim 19, wherein the telemetry data stored on the communications gateway unit includes one or more of: position, GPS data, altitude, acceleration, pressure, gas sensor (e.g. methane) data.

21. The communications gateway unit of any previous Claim, the communications gateway unit including a serial port or a USB port.

22. The communications gateway unit of any previous Claim, the communications gateway unit configured to output telemetry data stored on the communications gateway unit via an interface of the communications gateway unit e.g. a serial port or a USB port.

23. The communications gateway unit of any previous Claim, the communications gateway unit configured to receive operational commands from a computer in communication with the communications gateway unit, such as being in communication with the communications gateway unit using the satellite transceiver, or using the first cellular transceiver or using the second cellular transceiver, such as being in internet communication with the communications gateway unit using the satellite transceiver, or using the first cellular transceiver or using the second cellular transceiver.

24. The communications gateway unit of any previous Claim, wherein the communications gateway unit is suitable for a Remotely Piloted Aircraft (RPA).

25. The communications gateway unit of any previous Claim, wherein the communications gateway unit is cuboid shaped.

26. The communications gateway unit of any previous Claim, wherein the communications gateway unit has dimensions between 10 cm by 6 cm by 4 cm, and 20 cm by 15 cm by 8 cm.

27. The communications gateway unit of any previous Claim, wherein the communications gateway unit has a volume in the range 300 cm³ to 1200 cm³, and/or a mass in the range of 400 g to 1000 g, and/or operates in a power range between 2 W and 20 W.

28. The communications gateway unit of any previous Claim, wherein the communications gateway unit includes a WiFi transceiver.

29. The communications gateway unit of any previous Claim, wherein the communications gateway includes more than two cellular transceivers, for example where each cellular transceiver uses a different network provider.

30. The communications gateway unit of any previous Claim, wherein the communications gateway is configured to manage one or more of, or all of, a command and control link, a Sensor link, a RoIP link, a Video link.

31. A Remotely Piloted Aircraft (RPA) including a body and a communications gateway unit of any previous Claim.

32. The RPA of Claim 31, wherein the communications gateway unit is installable into, and removable from, the body of the RPA.

33. The RPA of Claims 31 or 32, wherein the communications gateway unit is installed inside a wing of the RPA.

34. The RPA of any of Claims 31 to 33, wherein the RPA is configured to receive primary command and control commands for the RPA via the satellite transceiver.

35. The RPA of any of Claims 31 to 33, wherein the RPA is configured to receive primary command and control commands for the RPA via the first cellular transceiver or via the second cellular transceiver.

36. The RPA of any of Claims 31 to 35, wherein the communications gateway unit is switchable to receive primary command and control commands for the RPA from via the satellite transceiver, to via the first cellular transceiver or the second cellular transceiver.

37. The RPA of any of Claims 31 to 35, wherein the communications gateway unit is switchable to receive primary command and control commands for the RPA via the first cellular transceiver or the second cellular transceiver, to via the satellite transceiver.

38. The RPA of Claims 36 or 37, wherein the switching occurs seamlessly.

39. The RPA of any of Claims 31 to 37, wherein the RPA includes a UHF transceiver.

40. The RPA of Claim 39, wherein the UHF transceiver is configured to communicate telemetry data.

41. The RPA of Claim 40, wherein the UHF transceiver is configured to receive a response to transmitted telemetry data.

42. The RPA of any of Claims 31 to 41, wherein the RPA is configured to provide RoIP or VoIP communications, using the satellite transceiver, or using the first cellular transceiver or using the second cellular transceiver.

43. The RPA of any of Claims 31 to 42, wherein the RPA includes a Light Detection and Ranging (LIDAR) measurement system arranged to measure the distance above the ground or water of the RPA when in flight.

44. The RPA of Claim 43, wherein the RPA is configured such that the distance above ground or water measured using the LIDAR measurement system is compared with a GPS position, possibly supplemented by barometric pressure, to confirm that the distance above ground or water measured using the LIDAR measurement system is accurate.

45. The RPA of Claims 43 or 44, wherein the RPA is configured to determine a difference between the LIDAR measurements of the distance above the ground or water of the RPA when in flight and the distance above the ground or water of the RPA when in flight estimated using GPS and/or barometric pressure.

46. The RPA of Claim 45, wherein the RPA is configured to automatically recalibrate the distance above the ground or water of the RPA when in flight estimated using GPS and/or barometric pressure, using the determined difference.

47. The RPA of Claim 45, wherein the RPA is configured to automatically recalibrate the distance above the ground or water of the RPA when in flight measured using LIDAR, using the determined difference.

48. The RPA of any of Claims 31 to 47, wherein the RPA includes a video camera.

49. The RPA of Claim 48, wherein the video camera is a nighttime camera e.g. an infra red sensitive camera.

50. The RPA of Claims 48 or 49, wherein the video camera is configured to record video at a higher rate during take off and/or landing, and to record video at a lower rate at other times e.g. when flying over water.

51. The RPA of any of Claims 31 to 50, wherein the RPA includes a transceiver for automatic dependent surveillance-broadcast (ADS-B), e.g. wherein the RPA is configured to provide collision avoidance.

52. The RPA of any of Claims 31 to 51, wherein the RPA is configured to communicate with a Local Ground Station (LGS).

53. The RPA of Claim 52, wherein the RPA is configured to receive flight control commands from a pilot located at a Mission Control centre via the LGS.

54. The RPA of any of Claims 31 to 53, the RPA including a stored a flight plan, wherein the RPA includes a processor configured to execute a (e.g. real-time) fuel estimation algorithm that uses the present position and calculates the fuel that is estimated to remain upon completion of the flight plan, and communicates an alert to a pilot if the RPA needs to return to base before completing the flight plan in order to return with a set amount of fuel reserve.

55. The RPA of any of Claims 31 to 54, the RPA including sensors, in which sensors can be turned off during flight; and/or wherein the RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

56. The RPA of any of Claims 31 to 55, wherein the communications gateway manages one or more of, or all of, a command and control link, a Sensor link, a RoIP link, a Video link.

57. The RPA of any of Claims 31 to 56, the RPA including an autopilot, wherein the communications gateway transmits position data computed by the autopilot.

58. A Remotely Piloted Aircraft (RPA) including at least a satellite communications transceiver, a first cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver and a second cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) transceiver.

59. The RPA of Claim 58, wherein the first cellular transceiver (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) and the second cellular transceiver (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) are configured to use different cellular networks.

60. The RPA of Claims 58 or 59, wherein the first cellular (e.g. a non-roaming) transceiver is configured to communicate with a network that is an inshore network.

61. The RPA of any of Claims 58 to 60, wherein the second cellular (e.g. a roaming) transceiver is configured to communicate with a cellular network that is not an inshore network.

62. The RPA of any of Claims 58 to 61, wherein the first cellular transceiver is a non-roaming transceiver, and the second cellular transceiver is a roaming transceiver.

63. The RPA of any of Claims 58 to 62, configured to provide a satellite communications link to a server, and at least one cellular communications link to the server, using the first cellular transceiver or using the second cellular transceiver.

64. The RPA of any of Claims 58 to 63, configured to provide a satellite communications link to a server, and at least two cellular communications links to the server, using the first cellular transceiver and using the second cellular transceiver.

65. The RPA of any of Claims 58 to 64, configured to receive primary command and control commands for the RPA via the satellite transceiver.

66. The RPA of any of Claims 58 to 64, configured to receive primary command and control commands for the RPA via the first cellular transceiver or via the second cellular transceiver.

67. The RPA of any of Claims 58 to 66, switchable to receive primary command and control commands for the RPA from via the satellite transceiver, to via the first cellular transceiver or the second cellular transceiver.

68. The RPA of any of Claims 58 to 66, switchable to receive primary command and control commands for the RPA from via the first cellular transceiver or the second cellular transceiver, to via the satellite transceiver.

69. The RPA of Claims 67 or 68, wherein the switching occurs seamlessly.

70. The RPA of any of Claims 58 to 69, wherein the RPA is configured to provide RoIP or VoIP communications, using the satellite transceiver, or using the first cellular transceiver or using the second cellular transceiver.

71. The RPA of any of Claims 58 to 70, wherein the RPA includes a Light Detection and Ranging (LIDAR) measurement system arranged to measure the distance above the ground or water of the RPA when in flight.

72. The RPA of any of Claims 58 to 71, wherein the RPA includes a video camera.

73. The RPA of Claim 72, wherein the video camera is a nighttime camera e.g. an infra red sensitive camera.

74. The RPA of any of Claims 58 to 73, wherein the RPA is configured to communicate with a Local Ground Station (LGS).

75. The RPA of Claim 74, wherein the RPA is configured to receive flight control commands from a pilot located at a Mission Control centre via the LGS.

76. The RPA of any of Claims 58 to 75, the RPA including a stored a flight plan, wherein the RPA includes a processor configured to execute a (e.g. real-time) fuel estimation algorithm that uses the present position and calculates the fuel that is estimated to remain upon completion of the flight plan, and communicates an alert to a pilot if the RPA needs to return to base before completing the flight plan in order to return with a set amount of fuel reserve; and/or wherein the RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

77. The RPA of any of Claims 58 to 76, wherein the RPA includes respective apparatus and is configured to provide a respective function of the communications gateway unit of any of Claims 1 to 30.

78. A RPA, the RPA including a transceiver and a remaining fuel measurement device arranged to measure the (e.g. aviation) fuel remaining, the RPA configured to determine the present position, the RPA including a stored flight plan, wherein the RPA includes a processor configured to execute a (e.g. real-time) fuel estimation algorithm that uses the present position and the measured remaining fuel, and calculates the fuel that is estimated to remain upon completion of the flight plan, and communicates an alert to a pilot using the transceiver if the RPA needs to return to base before completing the flight plan in order to return with a set amount of fuel reserve.

79. The RPA of Claim 78, wherein the algorithm uses a purely geometric calculation of the remaining flight path.

80. The RPA of Claims 78 or 79, wherein the algorithm uses the current aircraft position and the waypoints remaining in the flight plan and calculates the approximate path that the RPA will take.

81. The RPA of Claim 80, wherein the approximate path is calculated as a series of segments which are straight lines or circular arcs.

82. The RPA of any of Claims 78 to 81, wherein the algorithm uses the known velocity of the aircraft in still air, the wind speed and direction.

83. The RPA of Claim 82, wherein the wind speed and direction are received via the transceiver.

84. The RPA of any of Claims 78 to 83, wherein the algorithm calculates the range of fuel that will remain at the end of the flight plan based on a range of wind scenarios.

85. The RPA of Claim 84, wherein the range of wind scenarios are received via the transceiver.

86. The RPA of any of Claims 78 to 85, wherein if any of the range of fuel that will remain on landing falls below a predefined threshold, the mission is automatically aborted, or curtailed, to avoid running out of fuel during the mission.

87. The RPA of any of Claims 78 to 86, wherein the calculated fuel use is the fuel burn rate multiplied by the calculated total remaining flight time.

88. The RPA of any of Claims 78 to 87, wherein the RPA is an RPA of any of Claims 31 to 77; and/or wherein the RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

89. A method of relaying data between a first RPA and a second RPA, the first RPA including a first satellite communications transceiver, and a first non-satellite communications transceiver, the second RPA including a second satellite communications transceiver, and a second non-satellite communications transceiver, wherein the first RPA and the second RPA are airborne, and are in sufficient proximity to communicate using the first non-satellite communications transceiver and the second non-satellite communications transceiver, the method including the step that if the first satellite communications transceiver of the first RPA malfunctions and if the second satellite transceiver is operational, then the first RPA and the second RPA communicate via the first non-satellite communications transceiver and the second non-satellite communications transceiver, the first RPA sending a communication to the second RPA that the first satellite communications transceiver of the first RPA has malfunctioned, the second RPA relaying this communication to a mission control centre using the second satellite communications transceiver.

90. The method of Claim 89, wherein the first non-satellite communications transceiver and the second non-satellite communications transceiver are both WiFi transceivers, or are both 868 MHz radio transceivers, or are both LoRa transceivers.

91. The method of Claims 89 or 90, wherein the second RPA receives instructions using the second satellite communications transceiver from the mission control centre for the first RPA to guide the first RPA back to base, and the second RPA sending those received instructions to the first RPA using the first non-satellite communications transceiver and the second non-satellite communications transceiver.

92. The method of Claims 89 or 90, wherein the second RPA continues to receive instructions using the second satellite communications transceiver from the mission control centre for the first RPA to guide the first RPA back to base, and the second RPA sending those received instructions to the first RPA using the first non-satellite communications transceiver and the second non-satellite communications transceiver, until the first RPA arrives back at base, or until the first RPA is in range of a cellular network through which the first RPA communicates with the mission control centre using a cellular transceiver of the first RPA.

93. The method of any of Claims 89 to 92, the first RPA including a transponder, wherein a "communications lost" emergency squawk code is not transmitted by the transponder.

94. The method of any of Claims 89 to 93, wherein the first RPA is a RPA of any of Claims 31 to 77, and/or wherein the second RPA is a RPA of any of Claims 31 to 77; and/or wherein the first RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m; and/or wherein the second RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

95. A method of relaying data between a first RPA and a second RPA, the first RPA including a first satellite communications transceiver, a first cellular transceiver and a first non-satellite communications transceiver, the second RPA including a second satellite communications transceiver, a second cellular transceiver and a second non-satellite communications transceiver, wherein the first RPA and the second RPA are airborne, and are in sufficient proximity to communicate using the first non-satellite communications transceiver and the second non-satellite communications transceiver, the method including the step that if the second cellular communications transceiver of the second RPA is out of range of a cell tower and first cellular communications transceiver of the first RPA is in range of a cell tower, then the first RPA and the second RPA communicate via the first non-satellite communications transceiver and the second non-satellite communications transceiver, in which the second RPA sends data to the first RPA, the first RPA relaying this data to a mission control centre using the first cellular communications transceiver.

96. The method of Claim 95, wherein the first non-satellite communications transceiver and the second non-satellite communications transceiver are both WiFi transceivers, or are both 868 MHz radio transceivers, or are both LoRa transceivers.

97. The method of Claims 95 or 96, wherein route plans are prepared and stored on each RPA to make sure at least one RPA has cellular coverage to send high rate (e.g. 4G) data back to the mission control centre from both RPAs.

98. An RPA including a plurality of transceivers and a transponder, the RPA configured such that if communication via all the transceivers is not available for a specified length of time (e.g. 15 seconds), the RPA broadcasts in response a Mode S emergency squawk code using the transponder.

99. The RPA of Claim 98, wherein the RPA is a RPA of any of Claims 31 to 77.

100. A method of identifying a source of emissions, the method including the steps of:

(iii) projecting a line through the positions at which a local maximum gas sensor reading was obtained towards a region of the target, to identify a source of the emissions in the region of the target.

101. The method of Claim 100, including the step of: (iv) storing the identified source of the emissions in the region of the target.

102. The method of Claims 100 or 101, wherein the line in step (iii) is a straight line.

103. The method of Claims 100 or 101, wherein the line in step (iii) is not a straight line, e.g. a polynomial fit, of order two (i.e. a quadratic) or of order greater than two.

104. The method of any of Claims 100 to 103, wherein the line is a best fit in a statistical analysis e.g. a regression analysis, which optionally includes wind speed and direction.

105. The method of any of Claims 100 to 104, wherein step (iii) includes performing a 3D Computational Fluid Dynamics (CFD) diffusion computation, for example including using estimates of the wind field and target shape, or wherein step (iii) is instead performing a 3D Computational Fluid Dynamics (CFD) diffusion computation, for example including using estimates of the wind field and target shape, to identify a source of the emissions in the region of the target.

106. The method of any of Claims 100 to 105, the RPA flying around the target in a horizontal plane.

107. The method of any of Claims 100 to 106, the RPA flying around the target in circles of different radii.

108. The method of any of Claims 100 to 105, the RPA flying around the target in a vertical plane.

109. The method of Claim 108, the RPA flying around the target in circle portions (e.g. semicircles) of different radii.

110. The method of any of Claims 100 to 105, the RPA flying around the target in three dimensions.

111. The method of any of Claims 100 to 106, 108 or 110, the RPA not flying in circular paths.

112. The method of any of Claims 100 to 111, the RPA including a transceiver, the RPA using the transceiver to transmit the stored recorded gas sensor readings and the corresponding positions of the RPA to a computer, the computer receiving the transmitted stored recorded gas sensor readings and the corresponding positions of the RPA, and the computer performing the analysis of steps (ii) and (iii).

113. The method of any of Claims 100 to 112, wherein the gas sensor is a methane sensor.

114. The method of any of Claims 100 to 112, wherein the gas sensor senses fluorinated gases, or hydrofluorocarbons (HFCs), or perfluorocarbons (PFCs), or sulphur hexafluoride (SF6) or nitrogen trifluoride (NF3), or NOx or SOx, or C02.

115. The method of any of Claims 100 to 114, wherein the RPA includes a plurality of gas sensors, and the method includes recording gas sensor readings and the corresponding positions of the RPA for the plurality of gas sensors, the RPA storing the recorded gas sensor readings and the corresponding positions of the RPA for the plurality of gas sensors, and performing steps (ii) and (iii) for respective stored gas sensor readings.

116. The method of Claim 115, wherein the detection of different gases is used to identify the type of leak or emissions.

117. The method of any of Claims 100 to 116, wherein the RPA is a RPA of any of Claims 31 to 77; and/or wherein the RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

118. A method of identifying a source of emissions, the method including the steps of:

(iii) projecting a line through the position at which a local maximum gas sensor reading was obtained towards a region of the target, and using the wind speed and direction, to identify a source of the emissions in the region of the target.

119. The method of Claim 118, including the step of: (iv) storing the identified source of the emissions in the region of the target.

120. The method of Claims 118 or 119, wherein the line in step (iii) is a straight line.

121. The method of any of Claims 118 to 120, wherein step (iii) includes performing a 3D Computational Fluid Dynamics (CFD) diffusion computation, for example including using estimates of the wind field and target shape, or wherein step (iii) is instead performing a 3D Computational Fluid Dynamics (CFD) diffusion computation, for example including using estimates of the wind field and target shape, to identify a source of the emissions in the region of the target.

122. The method of any of Claims 118 to 121, the RPA flying around the target in a horizontal plane.

123. The method of any of Claims 118 to 121, the RPA flying around the target in a vertical plane.

124. The method of any of Claims 118 to 121, the RPA flying around the target in three dimensions.

125. The method of any of Claims 118 to 124, the RPA not flying in circular paths.

126. The method of any of Claims 118 to 125, the RPA including a transceiver, the RPA using the transceiver to transmit the stored recorded gas sensor readings and the corresponding positions of the RPA to a computer, the computer receiving the transmitted stored recorded gas sensor readings and the corresponding positions of the RPA, and the computer performing the analysis of steps (ii) and (iii).

127. The method of any of Claims 118 to 126, wherein the gas sensor is a methane sensor.

128. The method of any of Claims 118 to 126, wherein the gas sensor senses fluorinated gases, or hydrofluorocarbons (HFCs), or perfluorocarbons (PFCs), or sulphur hexafluoride (SF6) or nitrogen trifluoride (NF3), or NOx or SOx, or C02.

129. The method of any of Claims 118 to 128, wherein the RPA includes a plurality of gas sensors, and the method includes recording gas sensor readings and the corresponding positions of the RPA for the plurality of gas sensors, the RPA storing the recorded gas sensor readings and the corresponding positions of the RPA for the plurality of gas sensors, and performing steps (ii) and (iii) for respective stored gas sensor readings.

130. The method of Claim 129, wherein the detection of different gases is used to identify the type of leak or emissions.

131. The method of any of Claims 118 to 130, wherein the RPA is a RPA of any of Claims 31 to 77; and/or wherein the RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

132. An RPA including a drop tube, the drop tube in attachment with the RPA at a pivot position, wherein in an unreleased configuration the drop tube lies in a horizontal position and includes a payload within the drop tube, the RPA including a release mechanism, wherein the RPA is configured to release the release mechanism to release the drop tube into a released configuration, wherein in the released configuration the drop tube pivots about the pivot position, to cause the payload to be released from the drop tube.

133. The RPA of Claim 132, wherein when the payload is released from the drop tube, the payload slides out of the drop tube.

134. The RPA of Claims 132 or 133, wherein the payload is released from, or slides out of, the drop tube under gravity.

135. The RPA of any of Claims 132 to 134, wherein the drop tube is in attachment with an underside of the RPA.

136. The RPA of Claim 135, wherein the underside of the RPA is the underside of the fuselage.

137. The RPA of any of Claims 132 to 136, wherein in the released configuration, the drop tube including the payload pivots about the pivot position under gravity.

138. The RPA of any of Claims 132 to 137, wherein the pivot position is near to a front of the RPA.

139. The RPA of any of Claims 132 to 138, wherein the drop tube has a length in the range of 1 m to 3 m.

140. The RPA of any of Claims 132 to 139, wherein the drop tube includes acrylic.

141. The RPA of any of Claims 132 to 140, wherein the payload includes a payload tube.

142. The RPA of any of Claims 132 to 141, wherein the payload includes a drogue chute.

143. The RPA of any of Claims 132 to 141, wherein the payload includes a parachute including a drogue chute.

144. The RPA of any of Claims 132 to 143, wherein the RPA includes a stored flight plan and a position determining apparatus, the RPA configured to release the release mechanism when the RPA position corresponds to a predetermined location in the flight plan at which the release mechanism is to be released.

145. The RPA of any of Claims 132 to 143, wherein the RPA includes a transceiver, wherein the RPA is configured to release the release mechanism when the RPA receives a release command via the transceiver.

146. The RPA of any of Claims 132 to 145, wherein in flight, aerodynamic pressure causes the drop tube to swing back up so it returns to its position in the unreleased configuration.

147. The RPA of any of Claims 132 to 146, wherein the payload includes an Automatic Identification System (AIS) / DSC (Digital Selective Calling) beacon, including an Integrated DSC transmitter, which on contact with water or ground automatically activates.

148. The RPA of Claim 147, in which on contact with the water an inflatable marker is deployed, and/or a marker dye is released into the water.

149. The RPA of any of Claims 132 to 148, wherein the RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

150. The RPA of any of Claims 132 to 149, wherein the RPA is a RPA of any of Claims 31 to 77.

151. A method of carrying out an aerial survey in a region, the method including the steps of:

(iii) the RPA flying to a landing place; wherein the RPA includes a transceiver, the RPA receiving camera settings via the transceiver, and implementing the received camera settings on the camera system.

152. The method of Claim 151, wherein the received camera settings include one or more of: Aperture size; Shutter speed; camera Azimuth angle; Adding filters to the camera lens(es).

153. The method of Claims 151 or 152, wherein the region is a region of a wind farm.

154. The method of Claim 153, wherein the region includes surrounding areas of the wind farm.

155. The method of Claims 153 or 154, wherein the wind farm is an offshore wind farm.

156. The method of Claims 153 or 154, wherein the wind farm is an onshore wind farm.

157. The method of any of Claims 151 to 156, the method including the RPA surveying the region performing one or more of: onshore pipeline monitoring (e.g. to detect leaks e.g. water leaks), inspecting weed distribution, crop monitoring, thermal surveying using thermal image cameras, mapping river habitats, mapping coastal habitats, mapping estuary habitats, identifying invasive non-native plants from the air, mapping algal blooms, mapping pollution, monitoring thermal plumes from the air.

158. The method of any of Claims 151 to 157, wherein the RPA uses a flight path including parallel sweeps with a fixed spacing and altitude that is selected in accordance with optical parameters of the camera system.

159. The method of any of Claims 151 to 157, wherein the RPA uses a flight path not including parallel sweeps with a fixed spacing and altitude.

160. The method of any of Claims 151 to 159, wherein the RPA sends a set of images based on the captured camera images (e.g. the set of images based on the captured camera images is sent at a rate of one per time interval e.g. one per minute), using the transceiver, back to a mission control centre, so the set of images based on the captured camera images can be reviewed at the mission control centre, e.g. to consider if the camera settings are appropriate.

161. The method of Claim 160, wherein the set of images based on the captured camera images are at a lower resolution than the captured camera images.

162. The method of any of Claims 151 to 161, wherein the captured images include images of birds and/or mammals.

163. The method of any of Claims 151 to 162, wherein RPA has a length in the range of 1 m to 5 m, or 1 m to 3 m.

164. The method of any of Claims 151 to 163, wherein during surveying the region, at least some of the time the RPA flies at an altitude of less than 600 m, or less than 400 m, or less than 200m.

165. The method of any of Claims 151 to 164, wherein the camera system is operated remotely.

166. The method of any of Claims 151 to 165, wherein the RPA flies using an auto pilot system included in the RPA.

167. The method of Claim 166, wherein the autopilot system is configured to fly a pre-planned route.

168. The method of Claims 166 or 167, wherein the autopilot system receives the planned routes of other RPA(s) operating in the region, and avoids the flight paths of the planned routes of other RPA(s) operating in the region, to provide collision avoidance.

169. The method of any of Claims 166 to 168, wherein the autopilot system includes collision avoidance procedures.

170. The method of any of Claims 151 to 169, wherein the RPA takes off and lands from within 2 km of the coast.

171. The method of any of Claims 151 to 170, wherein camera system includes a daytime camera system.

172. The method of any of Claims 151 to 171, wherein camera system includes a night time (e.g. infra red sensitive) camera system.

173. The method of any of Claims 151 to 172, wherein the transceiver provides a cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) link which is used to finely adjust any settings on the camera that needs low-latency feedback to do so effectively.

174. The method of any of Claims 151 to 173, wherein the RPA is a RPA of any of Claims 31 to 77.

175. A method of carrying out an aerial survey in a region, the method including the steps of: (i) a plurality of RPAs each including an autopilot and each receiving a respective flight plan, wherein the flight plans are configured so that the RPAs cannot collide during the aerial survey;

(iv) the RPAs flying to a landing place; wherein the RPAs each include a respective transceiver.

176. The method of Claim 175, the RPAs receiving camera settings via the transceiver, and implementing the received camera settings on the respective camera system.

177. The method of Claims 175 or 176, wherein a single pilot at a mission control centre is responsible for the plurality of RPAs flying simultaneously.

178. The method of any of Claims 175 to 177, wherein each RPA is an RPA of any of Claims 31 to 77.

179. The method of any of Claims 175 to 178, wherein if one or more RPA aircraft have cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) coverage, this is used to relay the data from the other RPA aircraft back to the central control.

180. The method of Claim 179, wherein the cellular (e.g. 2G, 3G, 4G, 5G, LTE, preferably 4G) link is used to finely adjust any settings on the camera of the RPA aircraft having cellular coverage, or on another RPA aircraft, that needs low-latency feedback to do effectively.

181. The method of any of Claims 175 to 180, wherein when the plurality of RPAs are being used in a surveying operation, each including and using a communications gateway unit of any of Claims 1 to 30, or hardware with equivalent functionality, the plurality of RPAs communicate using their respective cellular transceivers, eg. respective 4G cellular transceivers.

182. The method of any of Claims 175 to 181, wherein when the plurality of RPAs are being used in a surveying operation, one RPA is designated as the master RPA; the master RPA receives data from the other RPAs, and then the master RPA transmits its data and the received data from the other RPAs via the satellite transceiver of the master RPA to mission control servers.

183. The method of any of Claims 175 to 182, the method further including a method of any of Claims 151 to 174.