Rape Prevention System

PSST Rape Prevention Personal Security System

This PSST system does NOT wait until AFTER a rape had begun but it (silently) preempts an attack.

A mathematical approach of generating hyperbolas and intersecting them can calculate very precise locations. A microwave-based Rape Prevention Personal Security System - PSST can use a very simple jewelry transmitter to locate a girl who feels she is in danger, almost instantly, within one foot location precision anywhere in a large city, and tell Police EXACTLY where to go to protect her.

Police can learn the Exact Location of a young lady in distress in under 1/4 second. The location accuracy is better than one-foot in all three directions anywhere in a city.

To best explain this concept and system, it is easiest to describe an analogy. Imagine that you camped overnight in the Grand Canyon, and you just had a cheap tape recorder with you, and a watch with a second hand. There happen to be flat areas on both side walls of the canyon, which make two echoes to your "Hello!" You go to sleep but leave your tape recorder running all night. Sometime during the night, a very valuable meteorite crashed SOMEWHERE in the Grand Canyon. In the morning, you can walk directly to it!

All you have is your recording, which has the noise of the crash of the impact of the meteorite, and then two echoes of that sound off the two reflective walls. Amazingly, that is all you need!

It turns out that the three sound paths to your recorder can be mathematically analyzed into being two different possible hyperbolic map paths, based on the time differences and the speed of sound. There is only ONE possible intersection point where the two hyperbolas intersect, and THAT is the EXACT location of where the meteorite crashed! Even with a cheap tape recorder, you will know, within a few inches, exactly where the valuable meteorite is waiting for you! Note that this is a meteorite with NO onboard electronics!

Rape Prevention city layout demo (if this 1980 DOS program should not display, you can use your DOS Prompt and type in http://mb-soft.com/hyperpg2.exe which should always work). In 1980, I discovered on local Gainesville, Florida TV news that the University of Florida would announce between five and eight rapes on Campus EVERY DAY. I found it incredibly depressing to watch the news, knowing that they were going to announce more rapes every day. This inspired me to try to find some way to help protect the Coeds on Campus, and I soon came up with this PSST system.

I designed an extremely simple and tiny (microwave) "jewelry transmitter" that only creates a single extremely brief beep, much like the extreme lack of technology of the canyon meteorite and the crash impact sound. I designed a "repeater station" which acts much like the echo wall of the canyon. I designed three separate "receiver antennas" which each first "hear" the signal from the "jewelry transmitter" and also then a moment later the signal that comes from the "repeater." All that is actually important is the TIME INTERVAL between those two received signals (in nano-seconds). Each receiving antenna merely receives two microwave radio signals, first directly from the girl's tiny jewelry transmitter and then the signal from the "repeater". Each receiver antenna then has the capability to create mathematical hyperbolas, somewhere on which the girl currently is. When the three sets of hyperbolas are then matched (in a Police Station) there is only one possible location where the girl could be. The actual moment of WHEN the signals were sent or received is irrelevant. The precise time as known by a jewelry transmitter or any of the three receivers is irrelevant. In this, this system is immensely different from how GPS works, which requires at least four satellites to all agree incredibly well as to what the time is (and each GPS satellite has to constantly be updating its computer clock for adequate accuracy). The GPS device must also precisely agree with all those satellites as to the precise time, and extensive calculation is then necessary to determine the precise location of each of the GPS satellites, since they are each orbiting the Earth at extremely high speed. The actual satellite-based GPS system requires around two minutes of calculations to determine the position of the GPS device, and even then, only to around the nearest hundred feet accuracy. Modern GPS devices also involve many LAND BASED GPS transmitters to do nearly all of the quick position location that GPS is famous for doing.

The PSST system does not need to know or determine such multitude of changing parameters. Even the fact that all computer clocks are constantly slowly changing due to temperature or humidity or barometric pressure, is irrelevant for the PSST system.

The woman's jewelry does not even give off any sound or any other indication for the attacker to be aware of, but a Police Car is certainly ALREADY on the way, BEFORE the attacker even has any chance to begin to harass her. He simply will not have time to actually DO anything that he intended to do to her.

The PSST system operates vaguely similarly to an old and obsolete Coastal Navigation system called LORAN-C, with hyperbolic lines on navigation maps, but in one way it is exactly opposite of LORAN-C. That navigation system provided the results and the map lines ON BOARD THE BOAT to let the Captain know where he was. PSST does NOT tell the girl where she is. Instead it alerts a Local Police Station precisely where she is on a City Map. The Police then know EXACTLY where to send a Police Car to.

Even if the girl is in a moving vehicle, the PSST jewelry transmitter sends a repeated signal about once every second, and so the Police PSST Map shows the MOVEMENT of the vehicle, updated every second. Therefore Police would know what street the vehicle was driving down, at what speed and in what lane, and even where in the vehicle the girl happened to be. If the vehicle turns onto a different street, PSST would instantly know and so would the Police.

If the girl is in the bathroom of a seventh floor apartment, the Police would know what Floor to get off at from an elevator, and which apartment to immediately go to.

The extreme simplicity of the jewelry transmitter makes that part of the system simple and cheap to mass produce. When I presented this system to the Administration of the University of Florida in 1980, I wanted to charge each Coed $5 per month, in order to encourage some responsibility. The UF Executives and Police Department wanted to immediately give me a check for ALL 35,000 students (including all boys) and for all 12 months per year, due to their concern about possible lawsuits by some fearful male students.

Many additional details were involved. I insisted that each PSST renter bring it in to an Office that we would operate in Gainesville, once every three months, for two important purposes. We planned to have a special table where each jewelry transmitter would be placed on it and triggered. The entire PSST system would then be forced to react, and as long as it recognized the exact location as being on our table, the Police would not be alerted and yet the entire PSST system would be checked for proper operation, many times every day. This would also confirm that her specific jewelry transmitter was working fine and that its tiny battery did not yet need to be replaced.

The girls would get the reassurance in watching that their PSST device was working fine, and that we would constantly be checking that the entire system was properly operating, many times every day.

There are several web pages about the PSST system, with this primary one at http://mb-soft.com/psst/index.html

We are confident that PSST should ELIMINATE rape as an urban problem. Police would be alerted and on the way to save the girl, within a second, so that the attacker would only have a few seconds to try to do anything before a Police Car shows up! Other attempts to deal with this problem generally only react far too late, or they rely on a girl having the nerve to openly challenge a much bigger and stronger man, whether with an airhorn or karate or pepper spray. Girls know that such attempts at self protection might just anger the man into even worse reactions. PSST is VERY different in being totally silent and unnoticeable, and lightning fast and accurate where both she and, after a few newscast arrests, the attacker KNOWS that a Police Car will show up in moments. She might try to TALK to the attacker, to slow him down, even a few seconds, until the Police arrive, which figures to be far safer for her.

More specifically, each time the local Police arrest such an attacker, and it is made clear in the news report that NOTHING BAD HAD HAPPENED TO HER, it should not be long before the attackers REALIZE that there is NO POINT IN TRYING ON THIS CAMPUS, because they would KNOW that the Police would show up too soon. In fact, how could a possible attacker even know whether THIS girl even HAD a PSST jewelry device, on her finger or around her neck or wrist or ankle! Even girls who did not happen to have an actual PSST device, quite probably would become absolutely safe regarding ever being raped on that campus!

In my Meetings with the UF Administration, an elderly matron mentioned to me that SHE was often terrified and she intended to get one of the first PSST jewelry devices we would make available. Wow!

The PSST system needs to work at rather high radio frequency, at around 900 MHz or higher. When I was working with the University of Florida, the FCC authorized us to have a "clear channel frequency" for a two-year period during testing, with extended authorization expected later. The idea was to not have any other radio signal interfere with the very brief (less than a millionth of a second) PSST signal due to the extreme importance of ensuring that a young lady might be protected.

The PSST system also has a number of other beneficial functions, without any changes in any of the PSST equipment. For example, an elderly person might wear a necklace which included a PSST transmitter, but with an extra blip in the signal to identify it as an Elderly, one which REGULARLY sent out a signal once every hour. The Elderly wearer would NEVER have to press any button! The extreme precision of the location determination could sense when the necklace PSST transmitter happened to be at a location that was known to be at the bottom of a staircase, or within one foot height of any floor, to automatically notify a neighbor or an Ambulance. Several additional web pages briefly describe such additional benefits.

On a Different Subject, Lawn-Mowing:

An inexpensive ultrasonic audio version can locate a motorized lawn mower to within 1/8 inch precision, once every second. That is a simplified version of the full microwave-based Rape Prevention System

A much simpler, ultrasonic audio version of PSST can constantly (once every second) monitor the PRECISE (1/8" accuracy) location of a mechanical "clicker" or "chirper" mounted on a motorized lawnmower, so that a standard PC inside a house can monitor and control the movement of the lawnmower around the yard. This ultrasonic version can monitor the location of the mower once every second, to an X-Y position precision of better than 1/8", but only within the area of one yard. The PC could control the movement of the mower to avoid trees and flower beds, and such a mower might only cost less than $100 more than a conventional lawn mower (plus the existence of a generic PC in the house).

Yard layout for mower demo (if this should not display in some computers, you can use your DOS Prompt or Command Prompt and type in http://mb-soft.com/hyperpm2.exe which should always work).

Carl W. Johnson, Theoretical Physicist, Physics Degree from University of Chicago

There is a serious rape problem on American campuses and in American cities. Young women are having to experience an extremely traumatic experience far too often. I have heard figures where a co-ed student may have over a 25% chance of being raped during her 4-year college career.

I find that totally unacceptable. I know women that still carry the trauma of having been raped ten years after having been attacked. No one should have to go through that.

A device and system has been invented for rape prevention and personal safety and security. It is a small necklace, bracelet or other piece of jewelry which contains a tiny switch and a simple and tiny cel-phone-like microwave radio transmitter. If she presses her PSST device, it does not emit any sound so the rapist will not realize that help is coming. Seconds later, a Police Car would arrive! Her UNIQUE signal would send a very brief (just a few millionths of a second transmission) to each of four special receiving antennas and receivers in the University city. The PSST system detects and re-transmits one of those signals, so TWO brief signals arrive at each receiver antenna, only a few billionths of a second apart. That time delay is multiplied by the speed of light to know EXAXCTLY how far the girl was away when she triggered her PSST, WITHIN ONE FOOT. Some advanced mathematical analysis of hyperbolic patterns is then done in our computer, somewhat like the old Loran-C Coastal Navigation System, to determine WHERE SHE IS (X, Y, and Z, within one foot or better) and WHO SHE IS (so Police Officers could identify her instantly).

PSST is VERY inexpensive, and the piece of jewelry she would wear is small and simple to actuate. For college coeds, the transmitter could be rented for less than $5 per month! Within 1/4 of a second of her actuating the device, which is totally silent, the city's Police would know PRECISELY where she was (within about one foot or 1/3 meter!). This new system provides an immense amount of additional personal safety.

(For the record, the public version of the GPS technology is well known to only have an accuracy of around 80 feet or 25 meters, in any direction, so therefore location precision only can identify slightly less than an acre, or a portion of a city block where the girl might be. In addition, for GPS to work, the GPS device must first access at least four orbiting satellites which are each more than 22,000 miles away and then to receive complex data strings from each of them, and then the GPS device generally takes around twenty seconds to two minutes or longer before processing all that data. Modern GPS installations use many land-based transmitters (which are stationary and not orbiting the Earth at 17,000 mph. This PSST system is therefore FAR BETTER than any GPS device could ever be, in BOTH the amazing location precision and the lightning-fast speed of providing the information to Police.)

This PSST (PerSonal Security Transmitter) system is meant to be so accurate and so quick that the actual benefit is intended once a few attempts were made. Once attackers are stopped by Police near the very start of an attack (where the girl is hopefully still uninjured), and the local news media publicize it, our hope and intention is that potential attackers would be aware of that and not even try! If THEY become convinced that they WILL get caught, and before ever accomplishing their goal, we hope that most potential attackers are smart enough to realize that it is pointless to even try! THAT means PSST would then be the first true RAPE PREVENTION system.

The problem is much broader than just on college campuses. Women of all ages, in virtually all locations, now find it necessary to continually be alert to the possibility of this danger. Many have developed paranoid attitudes as a result of these fears.

Other aspects of modern society also represent potential danger for individuals. Robberies, car-jackings, rage, gang activities, and many other dangers, make all of our lives have some personal danger in them.

This concept was invented and Engineered in early 1980. This presentation was first placed on the Internet in May 1997.

Many different approaches have been tried to deal with this problem. In general, they have had limited value.

Currently, in my opinion, only MACE-type products and hand-held air-horn or siren-type devices have general benefit for the large numbers of coeds. All of the above are valuable, of course, but there still seems to be a need for additional safety. A MACE type product is really only useful if the young woman HAD ALREADY REALIZED potential danger and already had her hand on the device. That is often not the case in many real situations.

Actually, if I were to consider selling such devices, I might make it a very loud air-horn or siren-type noisemaker which the girl would be expected to THROW on the nearby ground. The impact with the ground would trigger an acceleration sensor inside it to make it start to make noise. The would-be rapist would suddenly have a new complication, that of a very loud noisemaker on the ground. WOULD he continue to try to rape the girl? Knowing that nearby people would certainly LOOK at what was going on? Or would he decide to try to pick up the noisemaker to try to disable or destroy it, in order to be able to continue with his attempt at rape? In any case, the girl MIGHT have a few seconds to try to run away, while the rapist was experiencing brief confusion. Best of all, rather than hurting the girl to try to get such a noisemaker from her, it is lying several feet away from her on the ground!

In addition, with the great increase of handguns, the large amounts of drug use (and purchase), and the frustration of many members of the lower classes with their lot in life, the crime rate in general is increasing at a rapid rate. Getting mugged for a few dollars is becoming far too common. In addition to the co-eds, it would be useful for the general populace to have available an inexpensive personal safety device.

I have invented a VERY inexpensive system to provide a great amount of additional personal safety. I call it the PerSonal Security Transmitter or PSST. It represents a wonderful advance over current approaches to personal safety. It is essentially an "instant locating" system for anyone in distress.

The simplest way to explain the unique operation of this system is with an analogy. Imagine that you are camping near the bottom of a large canyon, which has at least two specific flat areas of canyon walls that make excellent echoes. While you are sleeping, you have a standard tape recorder, with a conventional microphone, running. During the night, in the dark, a valuable meteorite lands SOMEWHERE in the canyon, creating a sound of impact and two distinct echoes off the walls. Your tape recorder therefore has the record of THREE sounds on it. The actual impact will always be the first, as that sound traveled directly from the impact site to the microphone. The other two sounds will be delayed, because those sounds necessarily have to travel longer paths, first from the impact site to the canyon wall and then from that wall to the microphone.

I discovered a mathematical way of analyzing the time separations of those three recorded sounds, to PRECISELY identify the location of the impact sound, probably within one foot of the exact impact location, even though it occurred in pitch blackness! At your leisure the next morning, you can play back the recording and very accurately determine the SEPARATION IN TIME of the three sounds recorded. It is irrelevant as to whatever the exact time of impact actually was. Even the quality of the recorder would not be that critical, regarding how constant its motor moves the recording tape, as the ONLY time intervals that need to be known are only fractions of a second apart. A little calculation and you could walk right to the meteorite! (Actually, with that single microphone and recorder, there is no way of knowing which reflected sound was the first, so there would be two mathematical solutions and therefore two possible actual impact locations. If you also had a second microphone and recorder, in any other location, it would then be easy to know which echo was the first, to eliminate that uncertainty.)

If you want more about this basic concept, we know the speed of sound, around 1100 feet per second, and we know the exact distance between the microphone and the canyon wall that reflected the sound. The time delay on the tape recorder between the actual (direct) sound and such an echo therefore tells us how many extra feet of path there was between the direct path and the (combined) reflected path segments. This is actually a simple mathematical problem which results in a solution that is a hyperbola of points that could possibly be where the source (impact) was. A similar analysis of the actual direct sound and the SECOND echo gives a mathematical solution of a different hyperbola. The meteorite IS lying at the point where the two curves cross! Simple!

Our PSST system essentially enables the Police to do the same, to locate a young woman very quickly and very accurately, generally WITHIN ONE FOOT PRECISION, and in a fraction of a second, after she triggered a simple and inexpensive hand-held (or smaller) transmitter.

A critical aspect of this system is that the sound/signal source is so simple. No advanced electronics of any sort are involved or necessary. The meteorite certainly did NOT contain any electronic devices! All it did was make a simple but sharply defined sound of impact! The PSST device the young woman has only needs to have the most primitive of electronic device, because of this unique method of analysis, which allows using a very simple, inexpensive transmitter.

As to the analysis of the time reception, several years after I invented PSST, I discovered that a standard coastal Marine Navigation system, called Loran-C, has used similar (but backwards!) methods for over forty years. The intersection of hyperbolic curves is a well proven method of position determination.

More information on the Rape prevention PSST System. That discussion presents a small (bicycle-handle-sized or smaller) device that would be RENTED to each coed for less than $5 per month, affordable to any student. The monitoring part of the system recognizes her signal in a tiny fraction of a second, and displays her EXACT location (within about one foot!) ANYWHERE in that city, within 1/4 second of her pressing the device's triggers. In other words, the Police would almost instantly know that she was in need of help, and her name and description would also be displayed on the computer monitor. Squad cars dispatched would know precisely where to look and who to look for. It is realistic that the Police car would arrive within two or three minutes of when she pressed the triggers. The Officers could even call out her name, as though they knew her personally! This should assure that the attacker could not progress very far in his efforts and it should almost guarantee that he will be apprehended.

The system also re-calculates her position every second that she has the transmitter activated. If a perpetrator is dragging her into bushes or has put her in a vehicle, the PSST system would be able to track her movement! With the amazing accuracy of location that PSST has, the system will be able to continuously determine what street such a vehicle was on, which lane it was in, and even how fast it was moving!

The local news media would quickly spread the word that virtually anyone who even TRIED to rape any girl would certainly get caught, without even being able to complete the act. This is actually our central premise, that soon after PSST was operational, most potential attackers wouldn't even try! Our whole goal is that the number of rape ATTEMPTS would drop to near zero! And all this would be for an expense to each student of less than $5 per month or $50 per year!

The PSST system is designed to have a number of safeguards so the system is not subject to a lot of false alarms or regarding lost or stolen transmitters. There would be little sense in installing such a system if the Police soon chose to not follow them up! Descriptions of these features are included in our discussion in the other pages in this site.

Auto thefts are also on the rise. The auto alarms that people install in their vehicles don't seem to even draw any attention any more. Walk down a street of any large city and you'll hear alarms activated but no one even looks or checks them out. An improved alarm system would be useful, especially if it would also help find stolen cars. Some such systems ARE currently available, but they are pretty expensive and they all depend on that city's police cars to be outfitted with very expensive locating equipment. Further information on the PSST-based Vehicle Security Version.

Home security systems and home fire alarms are useful, but their benefits could be increased if the signal was noticed and acted upon right away. Further information on the PSST-based Home Security Version.
Further information on the PSST-based Smoke/Fire Version.

Elderly people are at increased risk of injuries, illnesses and falls. If this should happen when and where they are alone, it might be a great deal of time before help arrives. Some limited systems do exist to alleviate the dangers but they are somewhat expensive and often require the user to stay close to their home or phone. An improved, economical system would be beneficial. Further information on the Elderly Version of PSST.

The PSST System is all of these, and more! There are even some applications that would benefit the Military during training maneuvers and during complex battlefield conditions. Further information on the PSST-based Military Version.

Please Click Here for more comprehensive information on the PSST System. That discussion focuses on the use as a Rape Prevention device, but all the characteristics and operations are the same for the other System applications as well.

A technical presentation provides an explanation of the design and theory on which the PSST System is based and for instructions on creating and installing a PSST installation. For more information yet, please e-mail to the address below.

We consider this to be a Public-Service and the pages of this site contain all the information necessary to design and install the whole rape-prevention and elderly-protection system at no charge. Regarding possible use of the concept for products manufactured for profit, for auto protection, fire safety, home security or the other applications, we would require a contractual agreement. ONLY the rape-prevention and the elderly-protection versions of the PSST invention concept are intended to be offered at no or minimal charge. An exception to this offer applies regarding companies which intend to manufacture and/or market PSST-based rape prevention or elderly protection systems for profit.

I first invented this system in 1980 in Gainesville, Florida, in response to daily television news reports of how many rapes occurred that day on the Campus of the University of Florida. I thought it extremely impressive that the U of F was so open and honest with a problem that all other Colleges pretended did not even exist, so I dedicated myself to trying to help U of F to solve their horrible situation. I found it incredibly depressing to hear about the three or five rapes reported ON THAT DAY. If 1500 rapes occurred on Campus every year, that was around 6,000 in a four-year degree program. I knew that University of Florida then had around 16,000 co-ed students on campus. I quickly calculated that in a four-year College attendance, it implied that more than 30% of those College coeds were likely to be raped. (Years later, other Universities later admitted having similar problems, and it seems universally accepted today that on most major College Campuses in the US, a young woman currently has about a 25% likelihood of being raped before Graduation.) That HAS TO BE considered absolutely unacceptable. How could parents send their daughters to College if they were aware of this horrible situation? Worse, NO ONE ELSE seems to have provided significant methods of providing safety for those millions of young women>

PSST certainly CAN provide that safety, and more! I have attempted many times over the years since 1980 to get the PSST system operational. Sadly, I do not personally have sufficient expertise in microwave electronic circuitry to be able to build the necessary electronic devices, and I have been amazed at how little interest anyone else seems to have about trying to stop such rapes from happening! I put these pages on the Internet in May 1997. In the years after that, at least FORTY different people have contacted me and insisted to me that THEY have the necessary expertise, and most have bragged that they could finalize the design and wire up prototypes "in a few days". Yet, absolutely NONE of them ever have! One man, who presented himself as an absolute expert in such circuitry, told me that he was just too busy to do that, even though he insisted that it would only take him a few days to do. He informed me that he would need me to personally pay him $40,000 PER DAY such that he would re-arrange his schedule to do the needed work. First, I do not happen to HAVE a few hundred thousand dollars lying around to give to him for maybe a week of effort. Second, I considered it outrageously arrogant that he feels that his talents are worth $40,000 per day. And third, I wonder if his attitude will change WHEN a daughter of his happens to get raped!

I do not know if any of those forty people might actually have had the expertise to solve the final (seemingly small) hurdles which are keeping PSST from becoming operational, since none have them have ever even spent a few minutes working on the concept. However, between the long-time successful operation of the Loran-C marine coastal navigation system (which proves the value in the intersection of two hyperbolas approach) and its remarkable similarity to PSST in many ways, AND these many people who insist that they could each have solved the remaining electronics issues "in a few days", I continue to be optimistic that EVENTUALLY someone will step forward to "waste a few days of their infinitely valuable time" to enable hundreds of thousands of young girls to avoid a clearly horrendous experience.

There HAVE BEEN several non-microwave-electronics-experts who have contacted me and wanted to help. In each of those cases, they were extremely optimistic that they fully understood the situation and could provide the needed solutions. But in each of those cases, they were not aware of the strange things that occur at microwave frequencies! In case you are such a person who wants to help, there is an analogy that is useful. You flip a wall light switch when you enter or leave a room, and an incandescent light bulb illuminates the room. From a human perspective, the room becomes lit or dark "immediately or instantly". That is not actually the case! When electricity is sent to that light bulb, it actually takes quite a few milliseconds (thousandths of a second) before the filament heats up and is giving off light. In fact, the room GRADUALLY brightens up, with even the color changing, from a very brief very faint red light through orange and then yellow to what we call white light. Why is this important here? If we ask WHEN did the room light up, the answer SEEMS to be obvious, as being at the INSTANT when we flipped the switch. But if we require a precision of time of the nearest thousandth of a second, this becomes a very difficult question! Do you say that the room is lit when it is fully bright? Or just bright enough to see anything? The easiest answer tends to be the instant when it is HALF-BRIGHT, as that is a time that is fairly easy to determine accurately. Still, there can be some variation of a few milliseconds one way or the other, because the filament does not always heat up the exact same way each time. If we tried to ask, tell me that time to the nearest millionth of a second, the answer is essentially meaningless, because of those variations.

In microwave electronics, when you or any circuit simply closes a switch, it might initially seem that it is an instantaneous event, but that is NOT true! There are very few electronic devices that have a response time of better than around one one-millionth of a second. Yes, for all practical situations, that seems fast enough. But it isn't for PSST. We need to know the time of such events far more accurately than that, on the order of the nearest billionth of a second. So, for traditional circuit components, which take a thousand times that long to turn on or turn off, we have a situation resembling the room light switch.

There ARE some solutions to this. GPS accomplishes it in an immensely complex way, where it creates an EPIC several times, which takes half an hour to describe! Loran-C clearly accomplishes this need as well, but by mathematical analysis. There are also aspects of cel-phone operation and even Police radar guns, where very accurate timing of signals is done. So THERE ARE PEOPLE WHO KNOW HOW TO DO THESE THINGS. I have just never found one who has any interest in trying to prevent rapes from happening!

(The Technical Description page in this site linked above discusses the exact microwave circuitry details that are required.)

In 2007, a new technology called ShotSpotter has started being used in Oakland, California and some other cities. It is NOT the same as PSST, and works on a somewhat different basic concept, but it has some similarities. That ShotSpotter system is designed to have audio microphones installed in many places in a city to listen for the sound of gunshots.

That system operates on AUDIO waves instead of radio waves, so the operation is based on waves traveling at the speed of sound, 1100 feet per second, rather than the PSST's being based on waves traveling at the speed of light, about a million times faster at 1,000,000,000 feet per second. Their system is actually based on the long-used triangulation method of locating a source, but they use aspects that are vaguely similar to aspects of PSST. Specifically, their microphone devices actually contains four separate microphones, spaced a few inches apart in a square (horizontal) array. Each microphone hears the sound of the gunshot at a slightly different time, due to their slightly different distances from the gunshot source. A microprocessor compares those timing differences and is able to determine the approximate DIRECTION of the source. The device also contains a GPS receiver, but NOT for any of the actual GPS capability! It only uses the extreme accuracy of the exact TIME which the GPS satellites provide.

When the calculated directions are compared between different receiver assemblies, the DIRECTION lines tend to cross somewhere, which indicates the approximate location of the gunshot source. When the reception TIME values are then applied, then very accurate DISTANCE values are calculated (but only when several receivers' results are compared). This refines the location to become very accurately known, often within a few feet.

The ShotSpotter technology is NOT actually that similar to PSST, as it is actually based on simple triangulation methods, rather than the more sophisticated hyperbolic analysis of PSST. Still, the inclusion of examining the exact TIMES OF SIGNAL RECEPTION (actually in two different ways!) is an indication that something vaguely similar to PSST has come into existence.

The Loran-C coastal marine navigation system has long been the most similar technology to PSST, except that it uses the method in a reverse or backwards manner! Loran-C is entirely based on the same method of determining hyperbolic solutions to signal reception times and then determining the intersection point of two such hyperbolae. (I was NOT aware of the existence of Loran-C when I invented PSST, and consider the successful operation of Loran-C to be a wonderful proof that PSST will work exactly as I had calculated). However, Loran-C is "backwards" in that a fixed-location transmitter on land creates the initial pulse and also the re-transmitted pulse, and the analysis of the signal reception times is done by the device which is in a specific moving boat (The boat skipper is then able to see where he is on a map, which has hyperbolic curves drawn across it). This is remarkably similar to the PSST method, except for the fact that our INITIAL pulse is generated by the (portable) hand-held PSST device, the repeater is at a fixed location (exactly like Loran-C) and the analysis of the signal reception times is done by receiving devices in fixed locations. (The girl does NOT need to know where she is, but the PSST approach provides the location-analysis result to the fixed system).

Much of the technology of Loran-C therefore seems to be 100% applicable to PSST! However, it appears that Loran-C has become a dinosaur system (due to the arrival of GPS devices) and it appears that there are no longer any technicians who seem to understand the workings of or the circuitry for Loran-C! It seems certain to me that the circuitry that Loran-C uses to generate the initial signal creates a pulse that is well-defined in time, possibly sufficiently to give the accuracy that PSST is capable of, the one-foot location precision. The Loran-C repeater tower is certainly essentially identical to what is needed for PSST. And the Loran-C receiver used in a boat certainly has all the circuitry to accurately determine the DIFFERENCE in the reception times of the signals from the initial and repeated signals, EXACTLY what the PSST receivers need to do.

This all implies to me that PSST should be able to be assembled and operational IN WEEKS, by essentially entirely using surplus Loran-C equipment. However, no one seems to be familiar with any of that technology or that equipment. I suspect that even the CIRCUIT DIAGRAMS of Loran-C transmitters, repeaters and receivers might be all that is needed to get PSST (finally) operational.

This has been immensely frustrating because I do not have the personal expertise in microwave electronics circuitry, and have been unable to find anyone who has such knowledge who seems remotely interested in stopping rapes from occurring!

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E-mail to: cj@mb-soft.com

C Johnson, Theoretical Physicist, Physics Degree from Univ of Chicago