Big Blue Mars Final Report

Transcription

1 Big Blue Mars Final Report Member Names Kyle Hart Dale McClure Michael McEwen Contact Information Faculty Advisor Dr. Bill Smith Garret Chandler Advisor Contact Information

2 Abstract / Summary of Idea The purpose of this project is to solve the problem of communicating with an autonomous aircraft, known as Big Blue, at altitudes of over 100,000 feet. A solution to this problem is to create a module made to go inside the Big Blue aircraft that accepts up to 2 analog signals, modulates them, and then transmits them over a HAM radio frequency. The module should also be capable of receiving transmissions from a ground station and implementing a simple command on our aircraft. This solution will work well because the aircraft will be in line of sight to the ground station for most of the flight. With the use of directional antennas on the ground station, a low power transmitter can be used on the airplane, thus reducing power consumption and weight. Introduction In the past, the solution to the problem of transmitting telemetry from a high altitude was to use a handheld HAM radio that already had a Terminal Node Controller (TNC) built in. This transceiver was then connected to a custom built circuit board that contained the circuitry that controlled what sensor data was transmitted. The new idea for transmitting telemetry consists of a standalone TNC, Data Acquisition Board (DAQ) and transceiver. This idea of using already designed parts should decrease the complexity of this project, thus allowing more time to be spent increasing its functionality. For this project a ham radio license is needed to operate at these specific radio frequencies. The frequencies used for this project were MHz, the two meter band. Prior to working on this project, a Ham license was obtained by each group member. When a radio license is obtained a call sign is issued by the FCC. A call sign is a way to identify a station (person transmitting) over radio frequencies. Background As discussed above, the previous solution used a Kenwood TH-D7A transceiver with a built in TNC. This was interfaced with an application specific controller board that sent serial data to the transceiver. This design was a great deal more challenging in overall hardware interface complexity. The weight of the controller board and its components also presented a problem. The modular design solution being used in this project should be able to overcome these previous design problems.

3 Technical Description In Flight Module The block diagram of this project is shown on the next page (Figure 1). It consists of 4 main modules: the TNC, DAQ, transceiver, and battery pack. The power system (labeled Battery in Figure 1) will consist of batteries. The telemetry system will first take the analog output of two sensors and input those values into the DAQ. For use with sensors, the DAQ has two analog inputs. These inputs measure a voltage ranging from 0-5 Volts. It also has 8 digital ports that can be configured as inputs or outputs. Each of these can sink or source a maximum of 20 ma of current. The DAQ will then convert these I/O signals into a serial data stream. This data stream will then be sent to the TNC (1), which will modulate this data and send it as an audio signal to the transceiver. The transceiver will then transmit the data to the ground where it will be received by a ground station. A secondary objective of the design project, should time allow, is that the system would be able to receive commands transmitted from a ground station and control some aspect of the aircraft. The most important performance concerns with this project are to keep power consumption and weight to a minimum, as well as be able to receive data accurately from the airplane at altitudes of up to 100,000 ft. Power System In designing the power system there were two main design constraints. The first of these is weight. The entire aircraft should weigh no more than 12 pounds. The second design constraint is battery life. This telemetry module must be able to operate for a minimum of two hours. The power system must supply voltage to the TNC, DAQ, and transceiver. Each of these components requires different voltage ranges. The TNC requires a voltage of 6-12 volts, the DAQ needs 5-9 volts, and the transceiver will use 6 volts. To minimize weight, it was originally decided to use a single battery pack and regulate down the voltage at each component. However, since the TNC and the DAQ both can operate on 9 volts, these are supplied with 9 volts from three 3 volt batteries in series. The transceiver will only be hooked up to two of the three batteries having a common ground supplying it with 6 volts as required. The TNC could be supplied with 6 volts, however in research it was found that the TNC has complications with a low voltage (6 volts) so it supplied by 9 volts. The batteries used in this project have a 7.5AH capacity. Since we are using three batteries to supply our power that is 3*7.5AH=22.5AH available to our module. This is more than enough current for each of our components since the TNC only needs 50mA, the DAQ 15mA, and the radio 19mA all the time and 320mA when transmitting. By multiplying each of the components by two since the flight is two hours long, and adding up the totals we find that even if the transmit button is keyed up the entire length of the flight the entire module will only draw.808ah. This is only a fraction of what is available for usage in this project. Ground Station There are several options for ground station software. The DAQ manufacturer s website has many examples of code for BASIC and C programming. Also there are several tutorials explaining how to interface the DAQ to LABview and HyperTerminal.

4 HyperTerminal was chosen as it seemed to be the least complicated method. Another program used with the DAQ is ADRCOM Terminal Emulation Software. This program has limited functionality, but is a good way to test and learn about the DAQ. With this program you do not need HyperTerminal. Although when communicating with the DAQ through the transceiver HyperTerminal is used because of ADRCOMs limited functionality. Comparison to previous module Previously the radio system weighed 12 oz. and the communications board weighed 15.8 oz. This means the entire system weighed 27.8 oz. This was quite bulky compared to the presented design. Breaking the in flight module down, the transceiver weighs 5.7 oz. with an internal batter which will be removed prior to flight. The Picopacket (TNC) weighs 2 oz. After removing the case, and the DAQ weighs approximately 2 oz. also. This brings the total weight of this proposed design to 9.7 oz. This means that this new system weighs 18.1 oz. less than the old system.

5 Antenna Terminal Node Controller (TNC) Transmit / PTT Audio Data Transmit / Receive Radio Data Acquisition Module (DAQ) Control Signal Controller Sensor #1 Sensor #2 Battery (Figure 1: Block diagram of design project systems)

6 Distribution of Effort The effort will be divided fairly in the group. Dale McClure was mainly responsible for the programming and programming research of the hardware due to his background in this field. Kyle Hart and Michael McEwen made the final order sheet and ordered the parts for the project because they are the most familiar with the material. Kyle Hart and Michael McEwen also were responsible for the ground Station setup due to their interest and background in power and power systems. Kyle Hart and Michael McEwen also built the power system for the module due to their background in the power aspects of this project. Dale McClure assembled the communications due to his background in microcomputer organization and programming. The entire group worked on the final testing of the completed module because the knowledge of each individual system was needed. Status (Complete) The design was completed in every aspect with a few minor delays. The delays were in receiving in parts. To compensate for the parts not arriving on time, the power system was designed early and more research was done. Project Time Line (Figure 2: Approximate sequence of events) Milestones The group plans on having all of the parts ordered and received by February 28 th. Programming research will start February 20 th and last until March 1 st. Programming will start March 1 st and last until March 20 th. Ground station setup will start March 5 th and last until March 15 th. Power system will start March 15 th and last until March 20 th. Integrate parts together will start March 20 th and last until April 16 th. Testing and Corrections will start April 16 th and last until April 28 th. Report on April 24 th to May 3 rd.

7 Deliverables February 21 st design journal due. March 7 th design review presentations. March 9 th written design review and self and peer reviews. April 4 th design journal due. April 25 th will give final presentation. April 28 th will give final demonstration. May 3 rd final report and design journal due. Parts List Module Usable Part Cost Ground Station: Laptop Computer Free (available in lab) Kenwood Transceiver Free (available in lab) With TNC Directional Antenna Free (available in lab) In-Airplane Module: TNC (Will only need one of the following.) Paccomm (2) (Company that makes the Pico Packet) PicoPacket Base model $179 Two serial ports $269 (Ordered) Built in GPS $549 Tiny-2 MKII (possible) $169 DAQ (probable) Ontrack ADR101 series (3) $ Transceiver (probable) Alinco DJ-C7E $200 Batteries Single Use (Li-Ion) Rechargeable Free (available in lab) $50 + $100 for charger TOTAL $ This total fits well within our budget limit of $2500 imposed by Dr. Bill Smith.

8 Project Risks There were two problems that could have caused our project not to be finished on time. The first was not being able to transmit the TNC s callsign along with our data when flying the module. Sending the call sign using packet radio was decided to be the most favorable solution, and after reading the Picopacket manual this was implimented. Another problem encountered was that the Picopacket was on back order from the manufacturer for a long time. It eventually arrived though. The Picopacket was a vital part of the project and without it the project would have been difficult to continue. The main risk in the final design of this project is power failure. If the batteries run down to a low voltage, and the TNC input voltage stays at or below 6 Volts, the internal memory will be reset. This should not be an issue since the TNC is being driven with 9 Volts however. If, on the other had, the TNC loses power briefly and regains power, it will automatically attempt to reconnect at regular intervals. If a connection is needed immediately however, the command CONNECT XXXXXX (where XXXXXX is the Picopacket s callsign) can be issued from the ground station, and the connection will immediately be reestablished. Manual To start off, first setup the ground station. For this a computer and the Kenwood TH-D7 radio are needed along with the cable that connects the two. Open HyperTerminal on the computer (laptop) and connect it to the radio using the serial port on the computer and pc port on the radio. When HyperTerminal opens, set the COM port to whichever port the radio in connected to. Also, set serial port to 9600 bps, 8 bit, no parity, 1 stop bit, and no flow control. After HyperTerminal displays TNC welcome message and the command prompt, store a call sign into the TNC of the Kenwood radio. This is accomplished by typing mycall 'call sign'. The ground station is now ready. Before the in flight module can be connected the TNC must be programmed. To start issuing the TNC commands, it must first be connected to the serial port of a PC running HyperTerminal (9600 bps, 8 bit, no parity, 1 stop bit, and no flow control). Once the Picopacket is powered on, it will display a welcome message on HyperTerminal. To program the Picopacket, first a call sign is entered. This is accomplished by typing "MYCALL" followed by the call sign assigned to the Picopacket. The next command necessary is the TXDELAY command. This command controls how much time the transceiver is keyed up before data is sent. This can be set to a longer time to keep the ground station from missing packets. The default delay works fine for short range communication, but it might need to be adjusted for longer ranges. Following this command, a connection with the ground station must be established. This is done by typing CONNECT followed by the callsign programmed into the ground station TNC (the ground station must be turned on and ready at this point). When a connection is established, the Picopacket automatically goes into conversation mode. In order to keep the connection permanent, the command CONPERM ON is used. Before doing this however, the Picopacket must be placed back into command mode. This is done by pressing CTRL + C. Following this command, the command UIMODE ON is needed. This will instruct the Picopacket to automatically go into conversation mode when

9 powered up. After issuing all of these commands to the Picopacket, it is ready to be powered down. The Data Acquisition board should now be connected and the TNC rebooted. When the Picopacket powers up, it will automatically seek a connection from any TNC with the call sign of the ground station. One thing to note is that after the Picopacket connects to the ground station, it outputs a string of ASCII characters that show the new connection status. The DAQ cannot recognize these characters, so the carriage return command (implemented by pressing ENTER on the ground station) must be issued to clear the DAQ. If this is not done, the DAQ will not respond to the first command issued. To assemble the in flight module, gather the TNC (Picopacket), DAQ (ADR 101), and the radio (DJC7). First, power up all components using either the battery or power adapters. Now connect the radio to the TNC using cable 1, which plugs into the radio via the speaker/mic jack and the TNC's radio port. Connect the DAQ to the TNC using cable 2. This connects to the serial port to the DAQ and to the serial port on the TNC. After the TNC is programmed it will start looking for a connection with the ground station.

10 This is a screen shot of an unconnected ground station to show how data was received from the in flight module. Unconnected Ground Station Biographical Sketches Michael McEwen is a 4 th year Senior at the University of Kentucky, majoring in Electrical Engineering with a Math minor. Background is in power and communications. Michael is interested in radio transmission and edge of space sciences. Call Sign KI4NQD. Kyle Hart is a 5 th year Senior at the University of Kentucky, majoring in Electrical Engineering with a Math minor. Background is in communications and power. Kyle is interested in high altitude communications and the power system used to power the module. Call sign KI4NDX. Dale McClure is a 4 th year Senior at the University of Kentucky, majoring in Electrical Engineering. Background is in communications, embedded systems, and radio controlled

11 airplanes. Dale is interested in airplanes and long range Amateur Radio. Call sign KI4NDW.

12 References Internet sites: 1) Edge of Space Sciences: Internet site used to find information on high altitude launches and how different modules work. EOSS also has a list of various parts that might be used to build the module. 2) Site used to find parts for the module. Found the TNC from this site. 3) Site used to find parts for the module. Found the DAQ off this site.