Tracking Weapon Health and Maintenance
A system for tracking weapon health includes a low frequency networked radio tag coupled with a firearm, said radio tag configured to receive and send data signals; a reader configured to be in operative communication with the tag antenna; and a display configured to display data relating to weapon health. The radio tag includes a shot sensor, a shot count register for tracking the number of shots fired and cadence registers for tracking the intervals between shots.
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RuBee® is a registered trademark of Visible Assets, Inc. of the United States of America. Other names used herein may be registered trademarks, trademarks or product names of Visible Assets, Inc. or other companies.
To describe the foregoing and other exemplary purposes, aspects, and advantages, we use the following detailed description of an exemplary embodiment of the invention with reference to the drawings, in which:
While the invention as claimed can be modified into alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the scope of the present invention.DETAILED DESCRIPTION
We describe a long wave RuBee® active tag system and method for high order interval analytics for shot counting events data that are diagnostic of a current maintenance state and general health of a weapon.
Visible Assets, Inc. has developed signal processing methods resident on a low power, IEEE 1902.1 (RuBee) enabled four bit microprocessor, known as a RuBee Shot Counter. The chip includes a custom amplifier as well as what is called a ThinFir, which is a real-time finite impulse filter that converts a firearm shot into a single shot event. The telemetric data communication is based on IEEE 1902.1 and is integrated into a full weapons visibility network that can be used for physical inventory, entry and exit detection, and access control with RuBee ID badges, as well as visibility and physical inventory of other mission critical assets. The shot counting data and metrics contained in the RuBee tag may be read by a handheld, or process free within the visibility network. The tags have the advantage of being very small with a battery life of tens of years using small Li coin size batteries.
When any firearm is shot the barrel becomes worn. Additionally, as the weapon is shot the parts (springs, screws, and washers) in a gun that control the magazine and movement of bullets, as well as the hammer and other moving parts are worn. In many cases the status of these parts is directly proportional to the number of shots that have been fired. Therefore, shot counting and shot management using an electronic measurement system and wireless tag has the value to track use and maintenance of a weapon. After 3,000 rounds the manufacturer may recommend that all springs should be changed, or after 10,000 rounds the barrel may need to be replaced and so on. We have disclosed such a tag in a prior invention using long wavelength magnetic waves.
In many weapons the wear and tear may be accelerated depending upon how close the rounds were fired together. This is especially true in automatic and semi-automatic weapons that can fire up to 10-13 rounds per second. At this rate, the heat generated from bullets can have a harmful affect on the barrel and other moving parts, especially if it is sustained. In other words, in automatic and semi-automatic weapons, 3,000 rounds at one shot per second is acceptable, but 3,000 rounds shot at 10 rounds per second may make the weapon unusable and unsafe.
The 30 Round Clip Cluster Problem.
An additional more complex statistical issue comes with high speed automatic weapons. For example, assume a 30 round clip is shot in automatic mode, exchanged with a 2-3 second delay, with a next clip and a next clip. Therefore, 90 total rounds are shot. The wear on the barrel and components will be significant and the barrel may reach a temperature of 100 C. If the same clips are shot in automatic mode, but exchanged after ten minutes of cool down time, wear will be reduced. We call this the Clip Cluster problem. First order interval statistics using histograms, described below, will be identical in the two scenarios. A higher order statistic is required to differentiate and detect use of the weapon in automatic mode.
General Weapon Health and Diagnostics.
A third interesting issue is the performance of the weapon itself and may be both an indicator of the user skills, as well as an indicator of the maintenance state. The use of third and fourth order correlations between rounds to detect interval variability can be a good metric for the general health of the weapon.
We have developed unique statistical methods and applied them to round counting to address the issues outlined above. While advanced thermodynamic heating models are possible, a second requirement is that the analytics must be simple and capable of implementation on board using a 4 bit processor in real-time.
A simple firearm stochastic model was developed that assumes a gun could be fired up to 30 rounds per second in automatic mode at a rate of 13 to 8 rounds per second. Random Gaussian variation or jitter was added with controlled means and standard deviation. Time between clips was also a parameter from 2-3 seconds to many hundreds of minutes. Statistical methods were developed to simulate barrel temperature making specific simple assumptions. All data was analyzed using MatLab and Datadesk 6.0.
Weapons Wear Metrics.
The simplest metric is the number of shots counted (fired); therefore the weapon life and maintenance can be defined by the number of rounds fired. RuBee-enabled shot counters enable us to now count the shots automatically. However, not all shots cause the same amount of wear. For example, the first round through a cold weapon produces a given amount of wear. The last round of three clips fired at full auto produces significantly more wear.
Do we need to keep the last 90 intervals to produce a reasonable wear meric? Does wear produced by a round depend on the last 90 shot intervals? Yes, it can because the gun heats up faster with bursts of short interval shots. But time stamping every round is impractical. So we developed a simple real-time model that converts shot interval history to barrel temperature along with a set of simple equations. We add shot interval measurements shown in the shot interval histogram of
Weapons Wear Metric.
Mean Kinetic Shots (MKS) Wear Factor.
Key parameters for each weapon design has to be calibrated and checked.
Field data will lead to refined understanding of evidence based weapons healthcare.
For example, receiving information that a weapon jammed at 83 rounds merely indicates that there is a problem. With objective MKS field data and evidence based weapons healthcare, we can diagnose and repair weapon before it jams.
Finally, a normal probability plot of
A simple first order wear metric might be to assume that wear at 10-13 Shots/Sec is twice that at under one round per second. This ratio can be assigned to each weapon on a case by case basis. Again we emphasize this does not take into account the possibility of clip clusters that might lead to much higher wear, but the simple first order histogram may be adequate for most auto and semi-automatic weapons.
First Order Diagnostics
The first order interval statistics have the advantage of being simple and easy to obtain in real-time within a weapon. They also can be a strong indicator or diagnostic of the weapons' health. For example, the histogram seen below in
The left peak shows manual shots and the right peak shows rounds shot in auto mode. It is clear this histogram has a much lower mean and standard deviation. The right auto mode is shown in
In an attempt to address the Clip Cluster problem wherein many clips are shot at once in short intervals, we developed a Mean Kinetic Shot (MKS) algorithm that takes into account both heating and cooling of the mechanisms and barrel. The MKS factor is calculated using very simple assumptions, such as: a) barrel temperature increases by one unit each time the weapon is shot; b) barrel temperature decreases by a 0.1 unit every second; and c) as the barrel temperature increases, wear based on a single round will also increase.
Assumption a) is most accurate, that a round will increase the temperature of the barrel as it passes though the barrel the same amount at 13 Shots/Sec or 0.5 Shots per second.
The assumption b) that the barrel cools as a function of time is also correct although it is more likely the cooling is exponential and not linear. For simplicity, in this model we have to assume that it is linear with time.
Assumption c) is again simplistic and we have assumed that it is linear with temperature. It is more likely a higher order function that must be determined empirically for each weapon. However, for the sake of simplicity we have not scaled this as a factor, but that will become an important factor and differentiator between weapons.
We have presented the first order and second order statistical methods created for analysis of shot counting data. We have made simple assumptions to develop these methods. These assumptions may become more complex functions over time, but the principals developed here can be scaled based on empirical testing of individual weapons. That is by taking into account the weapon wear and health will be related to number of shots, but how those shots are distributed in time will also be a significant diagnostic factor.
We believe these methods can be used to predict wear and parts replacement in firearms, as well as serve as a real-time diagnostic for the health and safety of a firearm. These first order and second order analytics are simple enough to be calculated in real-time in a RuBee shot counting tag.
RuBee Firearm Visibility Network—Background.
The Firearm Visibility Network (FVN) provides for the identifying, monitoring and tracking of firearms within a network. RuBee® is a radio tag technology designed to provide full asset visibility and identification in harsh environments. The tags use the standard, IEEE P1902.1, “RuBee Standard for Long Wavelength Network Protocol,” which allows for networks encompassing thousands of radio tags operating below 450 KHz. RuBee® networks provide for real-time tracking under harsh environments, e.g., near metal and water and in the presence of electromagnetic noise. RuBee® radio tags, which can be either active or passive, have proven battery lives of ten years or more using inexpensive lithium batteries. The tags are programmable, in contrast to RFID tags.
The RuBee® Firearm Visibility Network (FVN) provides full visibility for storage, transport, and use of handguns, rifles, revolvers, and other weapons in high security government and law enforcement (LE) settings. The FVN may optionally include electronic identity cards to tie specific individuals to use/transport of weapons. See “Low Frequency Wireless Identification Device,” U.S. application Ser. No. 11/633,751 filed Dec. 4, 2006. The Firearm Visibility Platform may also provide independent audit trails for use in transport and storage of firearms that meet 21CFRPart11 compliance regulations and adhere to the Department of Defense (DoD) Directive 5015.2, “Department of Defense Records Management Program,” providing implementation and procedural guidance on records management in the DoD.
Background on RuBee® Radio Tags.
Radio tags communicate via magnetic (inductive communication) or electric radio communication to a base station or reader, or to another radio tag. A RuBee™ radio tag works through water and other bodily fluids, and near steel, with an eight to fifteen foot range, a five to ten-year battery life, and three million reads/writes. It operates at 132 KHz and is a full on-demand peer-to-peer, radiating transceiver.
RuBee® is a bidirectional, on-demand, peer-to-peer transceiver protocol operating at wavelengths below 450 KHz (low frequency). A transceiver is a radiating radio tag that actively receives digital data and actively transmits data by providing power to an antenna. A transceiver may be active or passive. The RuBee® standard is documented in the IEEE Standards body as IEEE P1902.1™.
Low frequency (LF), active radiating transceiver tags are especially useful for visibility and for tracking both inanimate and animate objects with large area loop antennas over other more expensive active radiating transponder high frequency (HF)/ultra high frequency (UHF) tags. These LF tags function well in harsh environments, near water and steel, and may have full two-way digital communications protocol, digital static memory and optional processing ability, sensors with memory, and ranges of up to 100 feet. The active radiating transceiver tags can be far less costly than other active transceiver tags (many under one dollar), and often less costly than passive back-scattered transponder RFID tags, especially those that require memory and make use of EEPROM. With an optional on-board crystal, these low frequency radiating transceiver tags also provide a high level of security by providing a date-time stamp, making full AES (Advanced Encryption Standard) encryption and one-time pad ciphers possible.
One of the advantages of the RuBee® tags is that they can transmit well through water and near steel. This is because RuBee® operates at a low frequency. Low frequency radio tags are immune to nulls often found near steel and liquids, as in high frequency and ultra high-frequency tags. This makes them ideally suited for use with firearms made of steel. Fluids have also posed significant problems for current tags. The RuBee® tag works well through water. In fact, tests have shown that the RuBee® tags work well even when fully submerged in water. This is not true for any frequency above 1 MHz. Radio signals in the 13.56 MHz range have losses of over 50% in signal strength as a result of water, and anything over 30 MHz have losses of 99%.
Another advantage is that RuBee® tags can be networked. One tag is operable to send and receive radio signals from another tag within the network or to a reader. The reader itself is operable to receive signals from all of the tags within the network. These networks operate at long-wavelengths and accommodate low-cost radio tags at ranges to 100 feet. The standard, IEEE P1902.1™, “RuBee Standard for Long Wavelength Network Protocol,” will allow for networks encompassing thousands of radio tags operating below 450 KHz.
The inductive mode of the RuBee® tag uses low frequencies, 3-30 kHz VLF or the Myriametric frequency range, 30-300 kHz LF in the Kilometric range, with some in the 300-3000 kHz MF or Hectometric range (usually under 450 kHz). Since the wavelength is so long at these low frequencies, over 99% of the radiated energy is magnetic, as opposed to a radiated electric field. Because most of the energy is magnetic, antennas are significantly (10 to 1000 times) smaller than ¼ wavelength or 1/10 wavelength, which would be required to efficiently radiate an electrical field. This is the preferred mode.
As opposed to the inductive mode radiation above, the electromagnetic mode uses frequencies above 3000 kHz in the Hectometric range, typically 8-900 MHz, where the majority of the radiated energy generated or detected may come from the electric field, and a ¼ or 1/10 wavelength antenna or design is often possible and utilized. The majority of radiated and detected energy is an electric field.
RuBee® tags are also programmable, unlike RFID tags. The RuBee® tags may be programmed with additional data and processing capabilities to allow them to respond to sensor-detected events and to other tags within a network.
Referring now in specific detail to the drawings and particularly
The radio tag 100 as shown in this example is placed in the handgun grip, but it could be placed in another part of the firearm if a different firearm form factor is used. The placement of the radio tag 100 depends on the form factor of the weapon and the size of the weapon. The tag 100 in this example is embedded into a cavity of the inside of the grip. Embedding the tag 100 in this manner is the preferred embodiment. Alternatively, the tag 100 may be affixed to the firearm by attaching it to the outside surface of the weapon, but this is not recommended.
The tag 100 may be constructed with a waterproof housing made to sustain wear and tear, yet remain lightweight.
Continuing with the discussion of the basic components, the tag 100 contains a custom RuBee® radiofrequency modem 1120, preferably created on a custom integrated circuit using four micron CMOS (complementary metal-oxide semiconductor) technology. This custom modem 1120 is a transceiver, designed to communicate (transmit and receive radio signals) through an omni-directional loop antenna 1180. All communications take place at very low frequencies (e.g. under 300 kHz). By using very low frequencies the range of the tag 100 is somewhat limited; however power consumption is also greatly reduced. Thus, the receiver of modem 1120 may be on at all times and hundreds of thousands of communication transactions can take place, while maintaining a life of many years (up to 15 years) for battery 1140.
Operatively connected to the modem 1120 is a RuBee® chipset 1125. The chipset 1125 is configured to detect and read analog voltages. The chipset 1125 is operatively connected to the modem 1120 and the microprocessor 1110.
The antenna 1180 shown in
The energy source shown in this example is a battery 1140, preferably a lithium (Li) CR2525 battery approximately the size of an American quarter-dollar with a five to fifteen year life and up to three million read/writes. Note that only one example of an energy source is shown. The tag 100 is not limited to a particular source of energy, the only requirement is that the energy source is small in size, lightweight, and operable for powering the electrical components.
The tag 100 also includes a memory 1130 and a four bit microprocessor 1110, using durable, inexpensive 4 micron CMOS technology and requiring very low power.
What has been shown and discussed so far is a basic embodiment of the tag 100. With the components as discussed, the tag 100 can perform the following functions: 1) the tag 100 can be configured to receive (via the modem 1120) and store data about the firearm to which it is attached and/or the network to which it belongs (in the memory 1130); 2) the tag 100 can emit signals which are picked up by a reader, the signals providing data about the firearm; 3) the tag 100 can store data in the form of an internet protocol address so that the tag's data can be read on the internet.
Note that the electrical components of the tag 100 are housed within the body of the tag 100 and are completely enclosed within the tag 100 when the device is sealed. This makes the tag 100 waterproof and tamperproof.
The tag 100 may contain additional features and components as will be discussed here below.Other Embodiments
The functionality of the tag 100 can be greatly enhanced with the addition of optional components. One of these optional components is a sensor 1150. The RuBee® chipset has the ability to detect and read analog voltages from various optional detectors 1150. Sensors 1150 may be included to provide positional information, use information, and other data to the microprocessor 1110. The number of sensors and the type of sensors depend on the intended use of the tag 100. For example, an activity parameter sensor may be used. The activity parameter sensor detects the number of shots fired by detecting the number of projectiles remaining in the cartridge. Another sensor 1150 may be able to detect if the tag 100 has been removed from the handgun. In fact, additional sensors may be placed on the back of the tag 100 for just this purpose. Each instance of motion and/or acceleration is a status event and it is detected by the sensor 1150. Sensors 1150 are ideal for providing an event history of the event statuses they detect. Other sensors not mentioned here may be advantageously used within the spirit and scope of the invention.
Additionally, a clock 1160 may be included inside the tag 100. The clock 1160 can provide a time history to correspond with status events detected by the sensors 1150. The clock 1160 can be configured to provide a time signal to correspond with a signal emitted by a sensor 1150. The processor 1110 records the time signal together with the sensor signal in order to provide a temporal history that can be mapped to a status history. The history data can be stored in the memory 1130 along with status events. Tying events to a time stamp provides for a more meaningful history of events. For example, mapping shots fired to a date and time affords very useful information.
The tag 100 may be programmed to emit a warning signal when at least one of the sensors 1150 detects a condition that meets a predetermined value. For example, a sensor 1150 in the tag 100 may emit a signal when the ammunition falls below a predetermined amount. A jog sensor 1150 may emit a signal when the weapon has been dropped. A signal could also be emitted when it is time to perform maintenance on the weapon.
To secure the stored data in the tag 100, an onboard crystal may be used to provide optical encoding using liquid crystal spatial light modulators. One-time pad ciphers are another security measure that can be advantageously used with a radio tag 100. Using known security measures with the radio tag 100 is recommended when needed to assure that the tag data does not fall into the wrong hands.
IEEE P1902.1 offers a real-time, tag-searchable protocol using IPv4 addresses and subnet addresses linked to asset taxonomies that run at speeds of 300 to 9,600 Baud. RuBee® Visibility Networks are managed by a low-cost Ethernet enabled router 1190. Individual tags and tag data may be viewed on a stand-alone system or a web server from anywhere in the world. Each RuBee® tag, if properly enabled, can be discovered and monitored over the World Wide Web using popular search engines (e.g., Google) or via the Visible Asset's tag Tag Name Server. Gathering information about one weapon is important. Equally important, if not more so, is gathering information about all of the weapons within a network. Note that in this discussion we refer to a “network” of weapons as all of the weapons within one networked RuBee® tag system. A network of weapons may or may not be restricted to one affiliation (such as a police department) or group of weapons (all revolvers). It is critical to track the shots fired, event histories, and condition of a network to be able to predict future events and to know what conditions will need to be changed and/or further monitored. It is well known in the art of database software that manipulating data in different ways produces different views of the data. Data from RuBee® tags 100 can be used for various purposes within the scope of this invention.
Optionally, a global positioning unit (GPS) 1195 may be operatively connected to the router 1190 to pick up the position signals detected by the tag's 100 optional positional sensor 1150 and record that information. The router 1190 and GPS 1195 unit can be placed in separate locations or may be co-located in a strategic location for optimal visibility of the firearm.
Next in step 1220, other data concerning the weapon is entered. This data may be the model number, the purchase date, the affiliation (agency, police department), and/or the maintenance record of the weapon, to name just a few data items that can be stored in the tag 100. The tag 100 is enabled to constantly transmit low frequency radio signals through its modem 1120. In step 1230 the identification data from the transceiver 1120 of the radio tag 100 is interrogated by the radio tag 100 with radio frequency interrogation signals at a low radio frequency not exceeding 450 kilohertz. The radio tag 100 may also transmit a signal or signals upon detection of a status event, such as a change in ammunition status of the weapon.
In step 1240 these signals are picked up by a reader operable to receive low frequency radio signals below 450 kilohertz within range of the tag antenna 1180. The reader may be a handheld reader, such as a wand reader. The signals may also be picked up by a router 1190, or another tag in the network.
In step 1250 the reader, router 1190, or handheld reader transmits the data via a wireless connection to a computer. The data may be encrypted with known encryption methods.
In step 1260 the transmitted data, after it is decrypted, if necessary, is viewable through a computer. The data may be accessed from a database configured to process the tag data and displayed through a computer monitor, or a personal digital assistant (PDA) screen, a cell phone display, or any other display means according to advancing technology. The data may also be viewable via web browser. When the data is available on the Internet, it then becomes critical to safeguard the data, either by requiring a login and password, or using data encryption methods known in the art. In one embodiment, the login name may be the serial number of the weapon.
In step 1270, the data gathered from the tag 100 or all of the tags in the network may be compiled into a report such as that shown. The report may be confined to one particular weapon, showing event and time histories for that weapon, or it may report on some or all of the weapons within an inventory shelf or a network. The report may be produced daily, monthly, seasonally, or yearly. The report may be automatically generated or may be generated upon user request. Optionally, a report may be auto-generated according to data received from the tag 100 which meets a pre-determined condition. For example, a user might want a report on a particular weapon generated when an ammunition sensor registers that the weapon has been fired. The report may be viewable on the Internet and/or distributed to appropriate personnel.
The purpose of generating reports is to provide information which can be used for predicting future trends and/or improving a situation, and/or for analyzing performance. Information gathered from a report may indicate that a change is necessary. The change may be a change in the data entered into the tag 100, or the data collected by the tag 100, or the position and/or frequencies of the equipment used to read the tags 100. You will recall that RuBee® tags 100 are programmable, unlike RFID tags 100.
Therefore, in step 1280 information gathered from a report may be used to add to or change the programming of the tags. To implement this, a user would make any needed changes on a computer. The data is transmitted to a RuBee® router 1190 which in turn communicates with a radio tag 100 through an antenna (either the tag antenna directly or a field antenna). The modem 1120 of the tag 100, using the chipset 1125 transmits the signals to the processor 1110. The processor 1110 records the data and makes the necessary changes. Many other additions and modifications can be made to the data to assist an end user in monitoring and tracking weapons within a network.
1. A system for tracking weapon health, the system comprising:
- a low frequency networked radio tag coupled with the firearm, said radio tag configured to receive and send data signals, the radio tag comprising: a modern, a tag antenna operable at a low radio frequency not exceeding 300 kilohertz, a transceiver operatively connected to the tag antenna, said transceiver configured to transmit and receive data signals at the low radio frequency, a data storage device configured to store data comprising identification data for identifying the firearm and shot count data, a processor configured to process data received from the transceiver and the data storage device and to transmit data to cause said transceiver to emit an identification signal based upon the identification data stored in said data storage device, a shot count register operatively coupled with the processor for tracking a number of shots fired, wherein the shot count register is incremented each time a shot is fired, a plurality of cadence registers operatively coupled with the processor for tracking an interval between shots, a shot sensor for detecting when a shot has been fired from the firearm, a timing mechanism for recording time used to determine shot cadence, and a connector for a power source to power the processor and the transceiver;
- a reader configured to be in operative communication with the tag antenna; and
- a display configured to display data relating to weapon health.
2. A system according to claim 1, wherein data is displayed graphically.
3. A system according to claim 1, wherein data is displayed as a histogram.
4. A system according to claim 1, wherein data relating to weapon health includes shot count and interval history.
5. A system according to claim 1, wherein each shot fired is assigned a wear value based on the number of the shot.
6. A system according to claim 1, wherein each shot fired is assigned a wear value based on the cadence of the shot.
7. A system according to claim 1, further comprising a weapon health calculator configured to calculate weapon health based on usage of the firearm.
8. A system according to claim 7, wherein the weapon health calculator calculates barrel temperature.
9. A system according to claim 8, wherein the heat differential of each shot fired is a temperature gain, and the temperature gain decays at a rate dependent upon the different between a barrel temperature and ambient temperature over time.
10. A system according to claim 7, wherein the weapon health calculator is further configured to calculate Mean Kinetic Shot (MKS).
11. A system according to claim 7, wherein the weapon health calculator is further configured to calculate weapon health based on characteristics of the firearm.
12. A system according to claim 7, wherein the display is further configured to graphically display the calculated weapon health.
13. A method for determining firearm health, comprising:
- assigning a wear value to each shot fired from a firearm based on;
- graphically displaying the wear value of each shot over a selected time; and
- analyzing the display to determine whether performance of the firearm changed over the selected time.
14. A method according to claim 13, wherein the wear value is assigned based on cadence.
15. A method according to claim 13, wherein the wear value is assigned based on barrel temperature.
16. A method according to claim 15, wherein barrel temperature is calculated based on shot count and cadence.
17. A method according to claim 13 wherein the wear value is assigned based on shot count.
Filed: Apr 21, 2014
Publication Date: Mar 19, 2015
Applicant: Visible Assets, Inc. (Mississauga)
Inventors: M. Jason August (Toronto), Rod Gilchrist (Oakville), John Stevens (Stratham, NH), Florin Tarcoci (Cornwall), Paul Waterhouse (Selkirk)
Application Number: 14/257,951
International Classification: F41A 19/01 (20060101);